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Monitoring diseases within tree canopies is challenging due to their inaccessibility and the complexity of canopy ecosystems. Here, we explore the potential of stemflow sampling as a novel, ground-based method for detecting and monitoring canopy-associated pathogens. In a case study focused on Litylenchus crenatae ssp. mccannii (LCM), the nematode associated with Beech Leaf Disease (BLD), we collected stemflow samples from 18 Fagus grandifolia Ehrh. (American beech) trees across 12 storm events. eDNA assays detected LCM presence in 7 of those storms, with quantitative PCR-derived gene concentrations ranging from 80 to 158,000 copies mL−1. Higher detections and concentrations coincided with leaf senescence and bud formation periods, and they correlated conditionally with event rainfall amount and pre-storm changes in relative humidity. Although based on a single site and season, these findings demonstrate the potential for stemflow sampling to capture a pathogen’s eDNA (i.e., canopy distress signals) at ground level. This method could complement traditional monitoring, offering another affordable, non-invasive tool for pathogen detection. Additional validation, particularly regarding live versus dead organisms and across varied site conditions, will be essential to evaluate the breadth of value stemflow eDNA offers for canopy disease management and ecological research. 

Abstract The episodic flanker task is an episodic version of the Eriksen and Eriksen (Perception & Psychophysics, 16(1), 143–149, 1974) perceptual flanker task, showing the same compatibility and distance effects. Subjects are presented with a list followed by a probe display in which one item is cued. The task, to indicate whether the probed letter appeared in the same position in the memory list, requires focusing attention on a single item in memory. The probe display contains flanking items to be ignored. They aresameas the memory list ordifferent.Sameflankers are compatible with “yes” responses and incompatible with “no” responses.Differentflankers are incompatible with “yes” responses and compatible with “no” responses. Previously, we presented multiple flankers in the probe, allowing a global matching strategy. Here, we report two episodic flanker experiments with just one flanker in the probe to encourage focusing sharply on the target. We found flanker compatibility effects in both experiments when a single flanker appeared immediately adjacent to the target. Experiment 2 varied the distance between the flanker and the target in the probe and the memory list and found the compatibility effect in response time only when the flanker was immediately adjacent to the target in both the probe and the memory list. The effect in accuracy also appeared when the flanker was two positions away in both the probe and the memory list. These results show that attention is focused sharply on elements of a memory structure during retrieval, suggesting that memory retrieval is perceptual attention turned inward. 

Abstract We report 10 experiments exploring the proposition that memory retrieval is perceptual attention turned inward. The experiments adapt the Eriksen and Eriksen perceptual flanker effect to a memory task in which subjects must decide whether a cued item in a probe display appeared in the same position in a memory list. Previous research with thisepisodic flanker taskfound distance and compatibility effects like those in the perceptual flanker task, suggesting that the same attentional spotlight is turned inward in memory retrieval. The previous experiments used lists of six consonants. The experiments reported here were designed to generalize the results to a broader range of conditions, from letters to words, colors, and pictures, and from set size 6 to set sizes of 4 and 5. Experiments 1–4 varied distance and set size with lists of four, five, or six letters, words, colors, and pictures, respectively. The distance effect was observed with all materials and all set sizes. Experiments 5–8 varied compatibility by presenting context items in the probe that were either the same as the memory list (and therefore compatible with “yes” responses and incompatible with “no” responses) or different from the memory list (and therefore incompatible with “yes” responses and compatible with “no” responses). We found compatibility effects with all materials and all set sizes. These results support the proposition that memory retrieval is attention turned inward. Turned inward or outward, attention is a general process that applies the same computations to different kinds of materials. 

Low-density meter-scale plasma waveguides produced in meter-scale supersonic gas jets have paved the way for recent demonstrations of all-optical multi-gigaelectronvolt laser wakefield acceleration (LWFA). This paper reviews recent advances by the University of Maryland, which have enabled these results, focusing on the development of elongated supersonic gas jets up to ∼1 m in length, experimental and simulation studies of plasma waveguide formation, and a new three-stage model for relativistic pulse propagation dynamics in these waveguides. We also present results from recent LWFA experiments conducted at the Laboratory for Advanced Lasers and Extreme Photonics at Colorado State University demonstrating high charge, low divergence electron bunches to ∼10 GeV, with laser-to-electron beam efficiency of at least ∼30%. 

Hydrodynamic plasma waveguides initiated by optical field ionization have recently become a key component of multi-GeV laser wakefield accelerators. Here, we present the most complete and accurate experimental and simulation-based characterization to date, applicable to current multi-GeV experiments and future 100 GeV-scale laser plasma accelerators. Crucial to the simulations is the correct modeling of intense Bessel beam interaction with meter-scale gas targets, the results of which are used as initial conditions for hydrodynamic simulations. The simulations are in good agreement with our experiments measuring evolving plasma and neutral hydrogen density profiles using two-color short pulse interferometry, enabling realistic determination of the guided mode structure for application to laser-driven plasma accelerator design. Published by the American Physical Society2024 

Historically, research in engineering education has taken a deficit-oriented perspective by focusing on the dearth of People of Color (POC) in engineering as a supply issue while ignoring the false narratives and discourses that dominate engineering education and research which exclude POC from the start. Recently, asset-based approaches have gained more traction in the field but too often miss a critical consideration: the hegemony of Whiteness in engineering. This theoretical paper is a deeper exploration of two crucial concepts that underpin the hegemonic discourse of Whiteness: meritocracy and colorblindness. We begin with a brief review of Whiteness studies which views Whiteness as the symbolic and structural white dominance and perceived superiority that marginalizes and oppresses POC and elevates white people to the top of the racial hierarchy (Matias & Newlove, 2017; McIntyre, 2002); a false ideal, guided by a historical mechanism of power, and the product of privileged social positions that benefits white people (DuBois, 1999). The purpose of this paper provides a critical perspective on how Whiteness tends to be at the foundations of these problematic narratives and discourses. The concept of meritocracy asserts that individuals are rewarded based solely on their individual effort, implying that people attain what they deserve in life through their hard work and determination. Conversely, those that are not successful are responsible for their lot in life. However, this belief in meritocracy overlooks the complex web of institutional and systemic variables that play a pivotal role in shaping life outcomes. A colorblind ideology fortifies the myth of meritocracy because it shifts the focus away from understanding how institutions perpetuate the normalized standard of white supremacy and racism, and instead places the responsibility for combating racism and white supremacy on individuals. This perspective bestows privileges upon white individuals as acts of merit if these privileges were earned solely through merit, rather than acknowledging that they are a product of a system that perpetuates advantages like a well-oiled assembly line. Meritocracy and colorblindness form a self-reinforcing cycle—a colorblind discourse in engineering education dominated by Whiteness willfully ignores the hierarchical positioning of racialized groups, fostering the misguided belief that success is determined by inherent merits. In reality, these merits are not objective or universal, but rather intangible attributes granted primarily to those who occupy the upper rungs of the hierarchical ladder within a colorblind society dominated by Whiteness and those who align with such an ideology. This theoretical paper begins to question the ways pedagogy and research are conducted in engineering education that traditionally exclude POC identities under the veil of equality, not equity. This ontological and epistemological shift is possible by questioning the very foundation that colorblindness and merit are built upon. The foundation of this work stems from an NSF grant to uncover the scripts of Whiteness in engineering education while devising a structured environment to help build individual and institutional racial literacy. 

Position-specific intrusions of items from prior lists are rare but important phenomena that distinguish broad classes of theory in serial memory. They are uniquely predicted by position coding theories, which assume items on all lists are associated with the same set of codes representing their positions. Activating a position code activates items associated with it in current and prior lists in proportion to their distance from the activated position. Thus, prior list intrusions are most likely to come from the coded position. Alternative “item dependent” theories based on associations between items and contexts built from items have difficulty accounting for the position specificity of prior list intrusions. We tested the position coding account with a position-cued recognition task designed to produce prior list interference. Cuing a position should activate a position code, which should activate items in nearby positions in the current and prior lists. We presented lures from the prior list to test for position-specific activation in response time and error rate; lures from nearby positions should interfere more. We found no evidence for such interference in 10 experiments, falsifying the position coding prediction. We ran two serial recall experiments with the same materials and found position-specific prior list intrusions. These results challenge all theories of serial memory: Position coding theories can explain the prior list intrusions in serial recall and but not the absence of prior list interference in cued recognition. Item dependent theories can explain the absence of prior list interference in cued recognition but cannot explain the occurrence of prior list intrusions in serial recall. 

Evidence-accumulation models (EAMs) are powerful tools for making sense of human and animal decision-making behavior. EAMs have generated significant theoretical advances in psychology, behavioral economics, and cognitive neuroscience and are increasingly used as a measurement tool in clinical research and other applied settings. Obtaining valid and reliable inferences from EAMs depends on knowing how to establish a close match between model assumptions and features of the task/data to which the model is applied. However, this knowledge is rarely articulated in the EAM literature, leaving beginners to rely on the private advice of mentors and colleagues and inefficient trial-and-error learning. In this article, we provide practical guidance for designing tasks appropriate for EAMs, relating experimental manipulations to EAM parameters, planning appropriate sample sizes, and preparing data and conducting an EAM analysis. Our advice is based on prior methodological studies and the our substantial collective experience with EAMs. By encouraging good task-design practices and warning of potential pitfalls, we hope to improve the quality and trustworthiness of future EAM research and applications.