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Pollination and Seed Production of \u3ci\u3eLavandula angustifolia\u3c/i\u3e Mill. (Lamiaceae)
Get PDFLavandula angustifolia Mill., lavender, is an aromatic plant in the Lamiaceae family. Lavender is an important economic plant that is cultivated throughout the world. Previous studies have shown that the primary pollinators of lavender in Europe and North Africa are bee species, specifically Bombus spp. However, similar studies have not been previously performed in North America. The current study, on cultivated population lavender (grown from seed) in Utah (USA), found a diverse community of bees visiting lavender over a 4-week sequential and successive blooming period. The observed and identified bees were distinguished across 8 genera and 12 species, of which 3 were species not native to North America. The most observed bees were Apis mellifera (88.3%), Bombus fervidus (4.2%), and B. huntii (3.7%). To investigate seed production and viability, lavender plants were either caged off and their access withheld from pollinators, or selectively granted access to various pollinators, to determine (1) if lavender is capable of self-pollination, (2) if pollination increases both the seed production rates and seed viability of lavender, and (3) which bee species are the most efficient pollinators of lavender. The findings from this study demonstrate the ecological interactions between pollinators both native and non-native to North America on lavender, a plant native to the Mediterranean region
Effects of Revegetation Approaches on Wetland Plant Community Reassembly Under Hydrologic Extremes
No full textActive revegetation is often necessary to recover native plant communities in disturbed or degraded wetlands. However, active revegetation has been pursued less in wetlands than other ecosystems and thus, there are few established best practices to guide implementation. Additionally, wetland revegetation is challenging due to dynamic hydrology becoming more extreme and high invasive plant propagule pressure that can limit native plant recruitment and favor invasive plant dominance. In this study, we tested the efficacy of varied revegetation approaches on native plant reassembly and invasion resistance in semi-arid wetlands subject to seasonal hydrologic fluctuations. In a Great Salt Lake wetland in Utah, USA, we introduced two functionally distinct native plant mixes, varied their method of introduction via seeding or planting, and varied their order of introduction over two planting dates. Unfortunately, there were no treatment effects on native or invasive cover, likely due to extreme drought in the first growing season followed by excessive flooding in the second. However, there were compositional shifts from drought-tolerant to flood-tolerant species throughout the study. Community compositional changes underscore the importance of including species with divergent and wide-ranging environmental tolerances in revegetation mixes to enhance native establishment across variable environmental conditions. This bet-hedging approach runs counter to the current focus on precision restoration—the method prioritizing the “right seed in the right place at the right time”—but may be an effective strategy to combat unpredictable conditions given increasingly extreme site conditions
The Memory-Keeping Daughter: Exploring Object Stories and Family Legacies From America\u27s Modern Wars
Get PDFThis essay demonstrates how wartime objects can have a special resonance in families as keepers of memory, and it especially explores the role of daughters of military participants in preserving the artifacts of their veteran fathers. Using several case studies from a recent public history project collecting objects and object stories in the American southwest, it argues that a focus on daughters as caretakers of family military history offers a new way to engage with descendants\u27 histories by showing how the work of such women can contribute to our understanding of modern war and its legacies
Comparative Analysis of Water-Induced Response in 3D-Printed SCF/ABS Composites Under Controlled Diffusion
Get PDFAdditive manufacturing (AM) or 3D printing of fiber-reinforced composites (FRCs) has garnered significant interests for its versatility in creating intricate parts and rapid prototyping due to cost-effectiveness. Although short fiber-reinforced thermoplastic composites are challenging to manufacture, their mechanical properties are enhanced. However, void formation during printing is a key issue, impacting mechanical properties and facilitating water ingress, affecting long-term durability. This work studies water diffusion characteristics and the associated hydro-aging of 3Dprinted short carbon fiber (SCF)/acrylonitrile butadiene styrene (ABS) composites with controlled water diffusion. Effects of material type (ABS and SCF/ABS), 3D printing path (horizontal and vertical filament orientation), and diffusion surface (uni-directional and bi-directional diffusion) on water diffusion coefficient and maximum water absorption level are characterized to ensure the long-term durability of 3D-printed ABS and SCF/ABS composites. Baseline representative volume element-based finite element (RVE-FE) diffusion models were developed based on microcomputed tomography (micro-CT) image analysis of each specimen to understand water diffusion characteristics. This work proves that the SCF/ABS composite is more resistive to hydro-aging than neat ABS due to the SCFs’ hydrophobic nature. SCF/ABS composites, while providing distinct advantages over pure ABS in terms of mechanical properties, could also be more effective against moist conditions
Do Firms Follow Through on Environmental Commitments? An Empirical Examination
Get PDFIn response to ever-increasing pressure from stakeholders to reduce the impact of their operations and supply chain on the natural environment, firms frequently make public commitments to improve environmental performance. However, the commitments are difficult to validate and thus of unknown quality. Understanding whether and when the commitments are valid proxies for action is essential because they are used by environmentally conscious stakeholders to assess firm environmental performance in anticipation of buying from, investing in, working for, or selling to a firm. Results from examining 442 U.S. manufacturing firms show that firms generally follow through on such commitments. Larger firms and firms with better environmental performance are more likely to follow through. However, firms tend not to follow through if they are experiencing negative environmental publicity or resource constraints at the time of the commitment. The results provide important insights for environmentally conscious stakeholders who use the commitments to determine whether to buy from, invest in, work for, or supply to a firm. The study also highlights the benefits to firm leaders of following through and provides input towards ideas that can increase follow-through. Finally, the study contributes to several streams of the research literature, including the literature evaluating environmental management, environment commitments, and environmental accidents
Neurocognitive Functioning in Adults With Trichotillomania: Predictors of Treatment Response and Symptom Severity in a Randomized Control Trial
No full textTrichotillomania (TTM) is associated with impairments in response inhibition and cognitive flexibility, but it is unclear how such impairments relate to treatment outcome. The present study examined pre-treatment response inhibition and cognitive flexibility as predictors of treatment outcome, change in these domains from pre- to post-treatment, and associations with TTM severity. Participants were drawn from a randomized controlled trial comparing acceptance-enhanced behavior therapy (AEBT) to psychoeducation and supportive therapy (PST) for TTM. Adults completed assessments at pre-treatment (n=88) and following 12 weeks of treatment (n=68). Response inhibition and cognitive flexibility were assessed using the Stop Signal Task and Object Alternation Task, respectively. Participants completed the MGH-Hairpulling Scale. Independent evaluators administered the NIMH-Trichotillomania Severity Scale and Clinical Global Impressions-Improvement Scale. Higher pre-treatment TTM severity was associated with poorer pre-treatment cognitive flexibility, but not response inhibition. Better pre-treatment response inhibition performance predicted positive treatment response and lower post-treatment TTM symptom severity, irrespective of treatment assignment. Cognitive flexibility did not predict treatment response. After controlling for age, neither neurocognitive variable changed during treatment. Response inhibition and cognitive flexibility appear uniquely related to hair pulling severity and treatment response in adults with TTM. Implications for treatment delivery and development are discussed