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Development of the 2025 Spring Melon (Cantaloupe) Crop
No full textThis article, published in the VegIPM Newsletter (Vol. 16, No. 11), documents mid-May melon development, noting that cooler conditions delayed maturity by calendar date but not by heat unit–based phenology benchmarks, validating the model’s reliability.Documents in the Arizona Pest Management Center collection are made available by the Arizona Pest Management Center (APMC) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact https://acis.cals.arizona.edu/about-us/arizona-pest-management-center
Urea Fertilizer Price Trends
No full textThis article, published in the VegIPM Newsletter (Vol. 16, No. 13), analyzes 2025 fertilizer market trends, noting sharp increases in urea and other nitrogen fertilizer prices linked to Middle East conflicts and global supply disruptions.Documents in the Arizona Pest Management Center collection are made available by the Arizona Pest Management Center (APMC) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact https://acis.cals.arizona.edu/about-us/arizona-pest-management-center
Mycorrhized Lygeum spartum is effective for the eco-restoration and phytoremediation of metal-contaminated soils in arid landscapes
No full textPlant species inhabiting industrial areas have evolved resilience in stressed environments and represent potential valuable resources for remediating polluted sites. However, data describing the potential of xeric plant species in sustainable green applications remain scarce. This study aims to evaluate the effectiveness of mycorrhiza-amended xeric plant species Lygeum spartum, in coping with arid conditions for phytoremediation and ecological restoration of degraded and contaminated lands. A six-month controlled pot experiment was conducted to assess leaf length, enzymatic activities, and secondary metabolites. Toxic metals and metalloids (TMMs) fate was evaluated using translocation factor (TF), bioaccumulation factor (BF) and removal efficiency (RE). Fungal inoculation positively impacted growth, increasing leaf size by 64.6 % and enhancing chlorophyll content - Chl a (0.73 mg g- 1 DW) and Chl b (0.64 mg g- 1 DW). Root uptake of Cd, Ni, Zn, Cu, Co, Cr and Pb was significantly enhanced in mycorrhizal plants (p < 0.05), and inoculation improved translocation of Zn, Cr and Co, with TFZn = 1.67, TFCr = 1.11 and TFCo = 1.05 respectively. Secondary metabolites included flavonoids, total phenols, glutathion-S-transferase, carotenoids, and antioxidants such as peroxidase (POD, 4.25 μmol min- 1 mg- 1 proteins), ascorbate peroxidase (APX, 2.14 μmol min- 1 mg- 1 proteins) and superoxide dismutase (SOD, 17.04 66 U mg- 1 protein). However, no improvement was observed in catalase activity or free radical scavenging potential. Therefore, xeric plant species amended with mycorrhiza are effective in TMM phytoremediation in arid environments and can be used for the restoration of degraded lands. Further, mycorrhiza could be used as sink cultures for the Phyto management and sustainable eco-restoration.University of Arizona24 month embargo; published 16 September 2025This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Essays on Information, Disclosure, and Search
No full textThis dissertation explores the incentives of manufacturers to communicate product attribute information to consumers strategically. Two essays examine how firms shape consumer knowledge and search behavior to create favorable competitive conditions, either in horizontal competition with rivals or in vertical relationships with suppliers.Essay 1 outlines how vertical interactions between the manufacturer and suppliers and the horizontal competition between suppliers determine a manufacturer’s incentives for information disclosure. Contrary to the classic literature on quality disclosure, which suggests that manufacturers of all quality levels should voluntarily disclose their private quality information to buyers, recent theoretical advances indicate that mechanisms such as vertical channel interactions may lead manufacturers to withhold high-quality levels. In contrast, empirical evidence and anecdotal observations show that many nonintegrated firms do disclose high-quality levels. This essay addresses this discrepancy by providing a theoretical explanation of how the nature and intensity of supplier-level competition influence manufacturers' incentives to disclose quality. I show that when suppliers are vertically differentiated, the manufacturer discloses all quality levels, regardless of the intensity of upstream competition. Moreover, when suppliers are homogeneous with asymmetric costs or horizontally differentiated, full disclosure can arise if competition is sufficiently intense. Otherwise, partial disclosure emerges, where the manufacturer discloses high and medium-low quality levels but avoids disclosing low and medium-high levels. Additionally, this essay identifies conditions under which channel instruments, such as side payments and pre-commitment to wholesale prices, can encourage manufacturers to disclose quality, thereby improving system profits. The results highlight the impact of disclosure on consumer welfare and product line decisions. Finally, in contrast with the channels’ literature, this essay demonstrates that when consumers are uncertain of quality, introducing upstream competition to a bilateral monopoly may hurt channel efficiency. Essay 2 provides a rationale for the use of product comparison tools and identifies the conditions under which this strategy is profitable. Some firms offer unbiased comparison tools on their websites, even when doing so reveals weaknesses in certain product attributes and risks losing customers already familiar with the firm. Using a game-theoretic framework, we conceptualize comparison tools as a strategic means of influencing the consumer search process by disclosing competing products’ attributes. The model considers manufacturer comparative disclosure and consumer search as two parallel information channels. Contrary to the expectations of regulators and policymakers, this essay shows that comparison tools can decrease competition and lead to higher market prices. It argues that by increasing consumer knowledge about competing products, comparison tools enable marketers to segment the market more effectively based on consumer fit, resulting in less elastic demand. Surprisingly, when firms are symmetric in quality, mutual comparison not only benefits them but also may increase consumer welfare. With firms asymmetric in quality, mutual comparison benefits those with closer quality levels; however, when the quality gap is wide, only the lower-quality firm benefits from comparison. The findings suggest that comparison by a higher-quality product is more likely to be profitable if it is more familiar to consumers or if consumer search costs are higher.Release after 09/15/202
From Design to Production for Metal Additive Manufacturing: A Dual Focus on Model-Based Design Guidance and Workforce Preparedness
No full textEffective use of additive manufacturing (AM) design freedom and rapid manufacturing capabilities requires designers to promptly address geometry-related quality issues, such as distortion, to ensure part accuracy. To date, AM part design has been a challenging and expensive process, given the complexity and cost of the AM process, the design freedom, and the limited availability of AM data. As a result, ensuring part design for improved quality hinders the broader adoption of AM technologies and may discourage designers from engaging with AM. The trial-and-error design process, based on time-consuming simulations, experiments, and ad-hoc rules, highlights the need for more efficient, data-driven design frameworks. Data-driven models can provide faster predictions of AM process-induced distortion, generate design guidelines by analyzing critical geometric features, and perform design compensation based on these distortion predictions. My research has three distinct aims focused on improving AM design processes and preparation of students for AM: (1) compensate part designs for minimizing part quality issues for the metal AM process, particularly laser powder bed fusion (LPBF), (2) efficiently predict AM part quality and provide design modifications based on the critical geometric features, and (3) explore engineering students experience in engineering, their engineering identity formation and engagement in makerspace to provide a scalable solution that increase students engagement in design and making activities like AM. To address the first aim, a key dimensional characteristics-based geometry compensation integrated remanufacturing framework for reverse engineering (RE) and AM was proposed. The proposed two distortion compensation algorithms utilized the 3D CAD model and the STL model. Findings indicated that STL-based compensation underperformed the CAD-based approach. The deviation distributions of the four remanufactured parts (two case study parts with two compensation methods) and their corresponding nominal geometries had mean values ranging from 30.0 μm to 48.9 μm and standard deviations ranging from 66.2 μm to 78.6 μm. The second aim is to develop a machine learning-based geometry-driven distortion risk (low, medium, or high risk) prediction model for a broad range of axisymmetric geometries. This model identified critical geometric features of parts that contribute to geometrical deviations and quality prediction, and provided targeted design modification recommendations for parts based on their predicted quality measures. This approach can deliver fast and high-quality predictions for a wide range of parts. Shape descriptors accurately classified distortion risk (with an accuracy of 86.4% for 81 test parts) and recommended design modifications to reduce distortion risks based on the key geometric feature trends for distortion risk classes. The third aim of understanding diverse students' engagement in making, makerspaces, and engineering, as well as their engineering identity formation, revealed emergent themes on making. For example, men and womxn (students who identified as women as one of their gender identities) may hold differing perspectives or exhibit varying interests in makerspace engagement, with men focused on specific technologies in the makerspace, while womxn are focused on space, community, and projects, and students feel more like engineers by the end of the semester. These findings can help develop more inclusive and engaging engineering courses, as well as support the development of the AM curriculum. The ML-based part distortion prediction and design recommendation, as well as the geometric feature-based design compensation model and the exploration of differences in engineering students' experiences and engagement in design and manufacturing, can support the broader goal of transitioning seamlessly from design and geometry capture to AM parts with reduced distortion. Model-based methods can capture the interactions among geometric features that impact part distortions, providing accurate and rapid predictions of distortion, design modifications, and compensation. Taken together, this dissertation reinforces the need for model-based methods and workforce training on design for quality that ensures both design intent and part quality in metal AM.Release after 08/22/202
FROM SUB-MEGAPIXEL TO MULTI-MEGAPIXEL RESOLUTION: A SCALABLE DMD-PLM HYBRID ToF SOLID-STATE LIDAR WITH DIFFRACTIVE AND HOLOGRAPHIC BEAM STEERING WITH CROSSTALK MITIGATION
No full textThis thesis discusses a novel hybrid optical LiDAR architecture that employs Texas Instruments’ Digital Micromirror Devices (DMDs) for coarse beam and image steering, a Phase Light Modulator (PLM) for fine field of view steering in a Time-of-Flight (ToF) solid-state LiDAR with contiguous panoramic LiDAR scanning and higher resolution imaging.By synchronizing the laser pulse to the dynamic tilt movement of the micromirrors on the DMD, a blazed grating condition can be satisfied, and light is diffracted and steered into one of the several diffraction orders with high diffraction efficiency. By employing Computer Generated Holograms (CGHs) on the PLM, the micro-mirrors’ height on the PLM can be modulated based on the hologram’s parameters, and a variety of grating patterns can be created for controlled image and/or field of view steering. There are multiple hierarchies of FoVs in this paper. For simplicity, the system’s total field of view is defined as the FOV of the system, the subdivisions of FOVs from the diffractive beam steering by DMDs are termed as ‘Sub-FOV’, and the finer FOVs within the sub-FOV of the DMD are termed as ‘Sub-Sub-FOV’. The proposed DMD-PLM Hybridized scanning and solid-state flash LiDAR architecture utilizes a near-infrared nanosecond pulsed laser, two synchronized DMDs (one for ‘Transmitter’ and the other for ‘Receiver’) for coarse sub-FOV beam steering, a PLM for finer sub-sub-FOV steering, and a Multi-Pixel Photon Counter (MPPC) to capture two-dimensional ToF LiDAR images. The experimental results demonstrate that the proposed LiDAR architecture increases the effective pixel count by 9-fold in a single sub-FOV by employing PLM sub-sub-FOV steering. There are seven diffraction orders from the DMDs used for coarse steering in the experiment, and each DMD order’s sub-FOV carries 9 sub-sub-FOVs from the PLM fine steering. Therefore, there is a 9-fold increase in the effective pixel count of the original LiDAR architecture, which only employed DMDs for the beam and image steering [2]. An addition of a holographic-based FOV steering PLM increases the pixel resolution by multiple folds in the LiDAR imaging by fine steering into the sub-FOV regions. With advantages, there exist some challenges in this hybrid LiDAR as well. There is the presence of the strong specular reflections at the 0th order due to the cover glass reflection from both the DMDs and PLM, as well as PLM’s 0th order interference with its higher orders from PLM’s MEMS mirror due to non-linearity and truncated phase modulation in the infrared region. The protective cover glass layer of both the DMDs and PLM is VIS/UV coated but not coated for infrared, causing strong Fresnel reflection at the 0th order. This unmodulated reflection introduces crosstalk between the 0th order and higher orders, making it difficult to distinguish higher-order diffraction images from the zeroth-order image. To mitigate this issue, a physical Fourier mask is applied to block the cover glass reflection from the transmitter-DMD, while a polarization-selective Fourier filtering technique is used to suppress the PLM’s cover-glass reflection and its zeroth order. This thesis presents a further advancement in the hybridized scanning and flash LiDAR architecture described by Chan (2023) [2]. The proposed new architecture enables an n²-fold enhancement in pixel resolution over Chan’s architecture of DMD-only based LiDAR by employing phase modulation with a PLM to perform sub-sub-FOV steering within each DMD’s sub-FOV. Along with the pixel resolution enhancement, this new architecture addresses the crosstalk issues caused by the cover glass specular reflection, beam spilling on adjacent orders, and gaps in beam steering and LiDAR imaging, utilizing a paraxial raytrace model for illumination design of the transmitter and contiguous receiver FOV design. Both the theoretical formulation and experimental validation of the resolution enhancement mechanism are provided. The crosstalk suppression techniques are effectively handled using Fourier-domain masking for DMD’s cover-glass reflection and polarization-selective filtering for the PLM’s cover glass and 0th order. The system is further supported by an analytical first-order model for contiguous, gap-free LiDAR imaging, and also demonstrates foveated scanning capabilities. These advancements offer significant potential for high-resolution, compact, and adaptive LiDAR systems in applications such as autonomous driving, robotics, and 3D mapping
Mobility Behavior and Urban Planning Challenges of Formal and Informal Transportation Systems in San Martín de Porres, Lima, Peru, 2025
No full textSustainable Built Environments Senior Capstone ProjectThe San Martín de Porres district, located in northern Lima, Peru, faces limitations on urban mobility due to uncontrolled urban growth, centralized opportunities, and the ineffective coexistence of formal and informal transport systems. The study analyzes how these factors affect citizens’ mobility behavior and how the lack of integration between the two transport systems affects the efficiency of the north-south transition in Gerardo Unger Avenue. The mixed-methods approach included participant observation, surveys, and document analysis to identify mobility patterns, inequities in accessibility, and high dependence on the north-south route. The data collection found that travel choices and mobility behavior depend on estimated travel times, perceived security, historical events, and cost-benefit alternatives. Urban mobility in northern Lima requires Transit-Oriented Development (TOD) strategies, the reorganization of road space, and urban design to support the coexistence of formal and informal transportation. It also proposes a multimodal mobility hub model that can be replicated according to uncontrolled urban growth. The model promotes equitable mobility, local development, and environmental improvements in complex urban contexts like northern Lima.This item is part of the Sustainable Built Environments collection. For more information, contact http://sbe.arizona.edu
Fundamental Limits of Covert Communication and Entanglement Generation over Quantum Channels
No full textWe establish the fundamental limits of covert communication over quantum channels, focusing on both finite-dimensional classical-quantum (CQ) channels and the infinite-dimen\-sional lossy thermal-noise bosonic channel. For general memoryless CQ channels, we characterize when covert communication is possible and prove a square root law (SRL): at most bits can be reliably transmitted covertly over uses of the channel where is the channel-dependent covert capacity. We derive a single-letter expression for and show that the required pre-shared secret key also scales as under mild conditions. We also identify and characterize corner cases where either constant-rate or zero-rate covert communication is possible. For the bosonic channel, we prove that the SRL holds and derive exact covert capacities under different resource assumptions. In particular, we show that the covert secrecy and covert entanglement generation capacities both equal the covert classical capacity without entanglement-assistance, , and show that the required pre-shared classical secret key scales as . We also find that quadrature phase-shift keying (QPSK) achieves the optimal covert capacity, outperforming binary modulation in contrast to the classical channel setting. When Alice and Bob instead share entanglement, the covert classical capacity improves to , though this scaling is sensitive to noise in the entangled resource. Finally, we propose a practical covert transceiver and simulate its performance compared to recently experimentally-tested transceivers under realistic conditions.Release after 06/16/202
Preserving Urban Green Spaces: The Role of Environmental Awareness in the Conservation of Parks in Cedros de Villa, Lima, Peru
No full textSustainable Built Environments Senior Capstone ProjectIn Cedros de Villa, Lima, neighbourhood parks provide important spaces for recreation, social interaction, and environmental quality; however, many parks currently show signs of deterioration and receive uneven maintenance. Although residents express concern for these spaces, they do not effectively conserve them, which raises doubts about how much environmental awareness actually contributes to the protection of urban green areas. The study used a qualitative methodology that combined perception analysis, online and interactive surveys, systematic observation of four parks, and six semi-structured interviews with key agents. The observations focused on physical conditions and maintenance, while the surveys and interviews explored levels of awareness, participation, and management limitations. The results show that residents demonstrate a moderate level of environmental awareness, reflected in emotional attachment and small individual care actions. However, weak community organization, a lack of technical guidance, budget restrictions, and reactive municipal management limit effective conservation. These factors reveal a clear knowledge–action gap between residents’ concern for the parks and sustained collective maintenance. The moderate environmental awareness of residents influences their attitudes and intentions to care for the parks, but it is not sufficient to ensure long-term conservation. Sustainable preservation requires combined support from institutions, organized community participation, technical assistance, and participatory, maintenance-oriented park design.This item is part of the Sustainable Built Environments collection. For more information, contact http://sbe.arizona.edu
Advancing Quantitative Abdominal MRI: Methods for Highly Accelerated T2 Mapping with Radial Turbo Spin-Echo Sequences
No full textMagnetic resonance imaging (MRI) is an especially powerful medical imaging modality due to its ability to provide excellent soft tissue contrast without the use of ionizing radiation. Drawbacks to MRI include its long acquisition times and resulting sensitivity to motion, which creates challenges in abdominal imaging, where respiratory motion is a concern. Although MRI is inherently a qualitative modality, meaning conventional clinical images have relative image intensity values that lack physical units, quantitative MRI (qMRI) has emerged as a method for using MRI to measure biomarkers within the body. qMRI typically involves fitting multiple MR images of different contrasts of the same anatomy to a physical model, further exacerbating the limitation of sensitivity to motion and slow acquisitions. T2 is one of the main parameters that controls contrast of conventional MRI, and the parameter values have been shown to hold significant clinical utility in diagnosing liver disease. The radial turbo spin-echo (RADTSE) sequence is ideally suited for T2 mapping of the abdomen due to its robustness to motion, ability to reconstruct a time series of co-registered images of different contrasts to fit to a T2 map, and its ability to be accelerated simply by collecting less data, which shifts the burden to the image reconstruction process to create high-quality images from incomplete datasets. We aim to improve highly accelerated abdominal T2 mapping using RADTSE via three main avenues. First, we develop pulse sequences that sample data more efficiently and strategically. Second, we improve the image reconstruction process using deep learning and other advanced methods to obtain high-quality images from sparse datasets. Finally, we make the parameter estimation process more robust and statistically interpretable to ensure T2 measurements are more reliable to be used for clinical decisions