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Background Host RNA-dependent RNA polymerases (RDRs) 1 and 6 contribute to antiviral RNA silencing in plants. RDR6 is constitutively expressed and was previously shown to limit invasion of Nicotiana benthamiana meristem tissue by potato virus X and thereby inhibit disease development. RDR1 is inducible by salicylic acid (SA) and several other phytohormones. But although it contributes to basal resistance to tobacco mosaic virus (TMV) it is dispensable for SA-induced resistance in inoculated leaves. The laboratory accession of N. benthamiana is a natural rdr1 mutant and highly susceptible to TMV. However, TMV-induced symptoms are ameliorated in transgenic plants expressing Medicago truncatula RDR1. Results In MtRDR1 -transgenic N. benthamiana plants the spread of TMV expressing the green fluorescent protein (TMV.GFP) into upper, non-inoculated, leaves was not inhibited. However, in these plants exclusion of TMV.GFP from the apical meristem and adjacent stem tissue was greater than in control plants and this exclusion effect was enhanced by SA. TMV normally kills N. benthamiana plants but although MtRDR1 -transgenic plants initially displayed virus-induced necrosis they subsequently recovered. Recovery from disease was markedly enhanced by SA treatment in MtRDR1 -transgenic plants whereas in control plants SA delayed but did not prevent systemic necrosis and death. Following SA treatment of MtRDR1 -transgenic plants, extractable RDR enzyme activity was increased and Western blot analysis of RDR extracts revealed a band cross-reacting with an antibody raised against MtRDR1. Expression of MtRDR1 in the transgenic N. benthamiana plants was driven by a constitutive 35S promoter derived from cauliflower mosaic virus, confirmed to be non-responsive to SA. This suggests that the effects of SA on MtRDR1 are exerted at a post-transcriptional level. Conclusions MtRDR1 inhibits severe symptom development by limiting spread of virus into the growing tips of infected plants. Thus, RDR1 may act in a similar fashion to RDR6. MtRDR1 and SA acted additively to further promote recovery from disease symptoms in MtRDR1 -transgenic plants. Thus it is possible that SA promotes MtRDR1 activity and/or stability through post-transcriptional effects.

Extreme weather events (EWEs) are expected to increase in stochasticity, frequency, and intensity due to climate change. Documented effects of EWEs, such as droughts, hurricanes, and temperature extremes, range from shifting community stable states to species extirpations. To date, little attention has been paid to how populations resist and/or recover from EWEs through compensatory (behavioral, demographic, or physiological) mechanisms; limiting the capacity to predict species responses to future changes in EWEs. Here, we systematically reviewed the global variation in species’ demographic responses, resistance to, and recovery from EWEs across weather types, species, and biogeographic regions. Through a literature review and meta‐analysis, we tested the prediction that population abundance and probability of persistence will decrease in populations after an EWE and how compensation affects that probability. Across 524 species population responses to EWEs reviewed (27 articles), we noted large variation in responses, such that, on average, the effect of EWEs on population demographics was not negative as predicted. The majority of species populations (80.4%) demonstrated compensatory mechanisms during events to reduce their deleterious effects. However, for populations that were negatively impacted, the demographic consequences were severe. Nearly 20% of the populations monitored experienced declines of over 50% after an EWE, and 6.8% of populations were extirpated. Population declines were reflected in a reduction in survival. Further, resilience was not common, as 80.0% of populations that declined did not recover to before EWE levels while monitored. However, average monitoring time was only two years with over a quarter of studies tracking recovery for less than the study species generation time. We conclude that EWEs have positive and negative impacts on species demography, and this varies by taxa. Species population recovery over short‐time intervals is rare, but long‐term studies are required to accurately assess species resilience to current and future events. Extreme weather events (EWEs) are expected to increase in stochasticity, frequency, and intensity as a result of climate change. Through a literature review and meta‐analysis, we tested the prediction that population abundance and probability of persistence will decrease in populations after an EWE. Across 524 species responses to EWEs reviewed (27 articles), we noted large variation in responses, such that, on average, the effect of EWEs on population demographics was not negative as predicted.

Ecology and management programs designed to track population trends over time increasingly are using passive monitoring methods to estimate terrestrial mammal densities. Researchers use motion-sensing cameras in mammal studies because they are cost-effective and advances in statistical methods incorporate motion-sensing camera data to estimate mammal densities. Density estimation involving unmarked individuals, however, remains challenging and empirical tests of statistical models are relatively rare. We tested the random encounter and staying time model (REST), a new means of estimating the density of an unmarked population, using human volunteers and simulated camera surveys. The REST method produced unbiased estimates of density, regardless of changes in human abundance, movement rates, home range sizes, or simulated camera effort. These advances in statistical methods when applied to motion-sensing camera data provide innovative avenues of large-mammal monitoring that have the potential to be applied to a broad spectrum of conservation and management studies, provided assumptions for the REST method are rigorously tested and met.

In recent years, it has been argued that the effect of predator fear exacts a greater demographic toll on prey populations than the direct killing of prey. However, efforts to quantify the effects of fear have primarily relied on experiments that replace predators with predator cues. Interpretation of these experiments must consider two important caveats: (1) the magnitude of experimenter-induced predator cues may not be realistically comparable to those of the prey’s natural sensory environment, and (2) given functional predators are removed from the treatments, the fear effect is measured in the absence of any consumptive effects, a situation which never occurs in nature. We contend that demographic consequences of fear in natural populations may have been overestimated because the intensity of predator cues applied by experimenters in the majority of studies has been unnaturally high, in some instances rarely occurring in nature without consumption. Furthermore, the removal of consumption from the treatments creates the potential situation that individual prey in poor condition (those most likely to contribute strongly to the observed fear effects via starvation or reduced reproductive output) may have been consumed by predators in nature prior to the expression of fear effects, thus confounding consumptive and fear effects. Here, we describe an alternative treatment design that does not utilize predator cues, and in so doing, better quantifies the demographic effect of fear on wild populations. This treatment substitutes the traditional cue experiment where consumptive effects are eliminated and fear is simulated with a design where fear is removed and consumptive effects are simulated through the experimental removal of prey. Comparison to a natural population would give a more robust estimate of the effect of fear in the presence of consumption on the demographic variable of interest. This approach represents a critical advance in quantifying the mechanistic pathways through which predation structures ecological communities. Discussing the merits of both treatments will motivate researchers to go beyond simply describing the existence of fear effects and focus on testing their true magnitude in wild populations and natural communities.

Although Three-dimensional (3D) printers have legitimate applications in various fields, they also present opportunities for misuse by criminals who can infringe upon intellectual property rights, manufacture counterfeit medical products, or create unregulated and untraceable firearms. The rise of affordable 3D printers for general consumers has exacerbated these concerns, making it increasingly vital for digital forensics investigators to identify and analyze vital artifacts associated with 3D printing. In our study, we focus on the identification and analysis of digital forensic artifacts related to 3D printing stored in both Linux and Windows operating systems. We create five distinct scenarios and gather data, including random-access memory (RAM), configuration data, generated files, residual data, and network data, to identify when 3D printing occurs on a device. Furthermore, we utilize the 3D printing slicing software Ultimaker Cura version 5.7 and RepetierHost version 2.3.2 to complete our experiments. Additionally, we anticipate that criminals commonly engage in anti-forensics and recover valuable evidence after uninstalling the software and deleting all other evidence. Our analysis reveals that each data type we collect provides vital evidence relating to 3D printing forensics.

Researchers have investigated career and technical student organizations (CTSOs) at the secondary level (Kosloski & Ritz, 2014; Russell et al., 2009; Stanislawski & Haltinner, 2009; Threeton & Pellock, 2010), but the value of CTSOs is unknown at the postsecondary level. This dissertation study focused on SkillsUSA, a CTSO available across the United States with participants at middle school, high school, and postsecondary levels for students enrolled in technical, skilled, and service occupation training programs (SkillsUSA, 2017). The study investigated how SkillsUSA participation influenced community college students’ preparedness for the workforce and connection to campus. The study also explored the influence of SkillsUSA participation on alumni’s program of study and career endeavors. A theoretical framework based on constructivism and the Psychology of Working Theory (Duffy et al., 2016) guided this work. This study used a qualitative case study approach to explore SkillsUSA chapters at two different community colleges in North Carolina. Data were gathered from interest questionnaires, interviews, and documents. Observations, field notes, and resumes provided additional context for the study. Findings revealed that while hometowns impacted access to job opportunities and industries, SkillsUSA participation influenced students’ work choices, initiative, and confidence in overcoming obstacles. Participants also reported support from peers, advisors, and the institutions. The study also provided evidence that while SkillsUSA participation did not influence all community college alumni to pursue a career and technical education (CTE) field, alumni gained more knowledge about CTE fields and considered themselves to be advocates for CTE. Findings also suggested that alumni were able to apply lessons they learned from SkillsUSA into work or educational settings. Understanding the experiences of these SkillsUSA members is of interest to community college administrators and practitioners; local, state, and federal policymakers and lawmakers; SkillsUSA chapters and advisors; CTE professional association representatives; CTSOs, students and families; and industry and employment professionals.

Old Farmer Humpkins gathered his pumpkins Info a heap by the banks of a river. Chanticleer Dorking that way was stalking Like a drum major, with plumes all...