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Niche Conservatism and Sympatric Parallel Evolution May Help to Maintain Eight Nascent Tree Taxa Along a Sharp Elevation Gradient
No full textPatterns of niche partitioning among closely related taxa, such as those in incipient adaptive radiations, can provide clues into how niches are created, partitioned, and integrated over ecological and evolutionary time scales. Hawaiian Metrosideros is a ~3-MYO adaptive radiation of trees that dominates the Hawaiian Islands in continuous stands within islands and allows examination of niche partitioning at the early stages of adaptive radiation. We monitored growth and survivorship over 2 years of seedlings derived from open-pollinated fruits of eight Metrosideros taxa distributed along the elevation gradient of Koʻolau Volcano, Oʻahu, under four combinations of light and phosphorus. We included four glabrous taxa, representing mixed lineages and four pubescent taxa, representing a single, Oʻahu-endemic lineage and tested hypotheses of differentiation among taxa and between glabrous and pubescent groups. Variation among taxa in response to light and phosphorus was modest, with high-elevation taxa showing relatively greater niche partitioning (per Pianka\u27s Index). Patterns of growth rate variation (plasticity) along the elevation gradient in response to light and phosphorus were similar between the glabrous and pubescent groups, with low-elevation taxa showing high and low plasticity to light and phosphorus, respectively. Patterns of survivorship across light and phosphorus treatments were highly concordant within the recently evolved pubescent lineage. Both growth rates and survivorship rates suggested the conservation of contrasting light niches within glabrous and pubescent groups. Finally, the retention of taxon-diagnostic phenotypes despite 2 years of growth under contrasting environments implied significant heritable differentiation among the eight taxa, despite the likely presence of hybrids in the open-pollinated seedlings. The coexistence of eight predominantly infraspecific tree taxa within the confines of Metrosideros forest on Koʻolau Volcano appears to result from a combination of niche conservatism within the glabrous and pubescent groups and sympatric parallel evolution between these groups along elevation gradients. The modest niche partitioning among taxa by light and phosphorus, especially at middle elevations, suggests that additional environmental factors contribute to local adaptation in these trees. Results of this study suggest that both stabilizing and diversifying processes contribute to the early stages of adaptive radiation in trees
Poly(pyridinium salt)s Containing 9,9-Bis(4- aminophenyl)fluorene Moieties with Various Organic Counterions Exhibiting Both Lyotropic Liquid-Crystalline and Light-Emitting Properties
No full textMain-chain conjugated and non-conjugated polyelectrolytes are an important class of materials that have many technological applications ranging from fire-retardant materials to carbon-nanotube composites, nonlinear optical materials, electrochromic materials for smart windows, and optical sensors for biomolecules. Here, we describe a series of poly(pyridinium salt)s-fluorene containing 9,9-bis(4-aminophenyl)fluorene moieties with various organic counterions that were synthesized using ring-transmutation polymerization and metathesis reactions, which are non-conjugated polyelectrolytes. Their chemical structures were characterized by Fourier transform infrared (FTIR), proton (1H) and fluorine 19 (19F) nuclear magnetic resonance (NMR) spectrometers, and elemental analysis. They exhibited polyelectrolytic behavior in dimethyl sulfoxide. Their lyotropic liquid-crystalline phases were examined by polarizing optical microscopy (POM) and small angle X-ray scattering (SAXS) studies. Their emission spectra exhibited a positive solvatochromism on changing the polarity of solvents. They emitted greenish-yellow lights in polar organic solvents. They formed aggregates in polar aprotic and protic solvents with the addition of water (v/v, 0–90%), whose λem peaks were blue shifted
“The Technology We’ve Been Forced to Use”: Impact of Online Service Delivery for Kinship Families During the COVID-19 Pandemic
No full textPurpose: The COVID-19 pandemic rapidly changed the service landscape for both professionals and families. Kinship families, who often navigate multiple systems concurrently with higher service needs, were among the most vulnerable. This study explores kinship caregivers’ and child welfare professionals’ perceptions of changes in service delivery during the pandemic, specifically the sudden shift to virtual platforms.
Materials and Methods: To understand participants’ experiences, focus groups with protocols shaped by initial Delphi Rounds were implemented with 25 kinship caregivers and 34 child welfare professionals from a national sample.
Results: Caregiver and professionals shared themes related to how COVID-19 precautions impacted service delivery; kinship families’ access to, knowledge, and use of technology; and benefits and challenges for implementing virtual support.
Discussion: Based on findings shared by participants, a model illustrating influencing factors for online service delivery was created highlighting technological capital, client factors, provider factors, and service type as key components. Implications of implementing online supports in practice are discussed, including technology access, training in social work education, and future research areas.
Conclusion: Despite the many adversities the COVID-19 pandemic presented for professionals and kinship families, this unprecedented time also paved the way for us think differently about service accessibility and the benefits and challenges of online supports, especially in a world that is quickly moving toward automation. Considering both families’ and professionals’ perspectives is key to integrating virtual supports into the current service delivery landscape in equitable and effective ways
Contribution of Various Factors On the Rate of Traffic Accidents in the Us
No full textBackground:
Until 2020, the number of traffic accidents has been steadily decreasing. After 2020, the number started increasing until 2022, then started s lowly decreasing again. Most drivers aren’t fully aware of the reason behind all of these accidents.https://oasis.library.unlv.edu/durep_lightning/1043/thumbnail.jp
Sweet Snacks Effects on Hispanic/Latino Childhood Obesity
No full textBackground:
Obesity rates in children has become a growing concern in the Hispanic/Latino community in Nevada. This study examines the availability of sweet snacks in the home and its association with children\u27s dietary behavior.
Methods:
Data was analyzed from a survey of 155 Latina mothers using logistic regression while controlling for income, education, and acculturation. The survey was conducted in Nevada, between October 2022 and March 2024.
Results:
The frequency of keeping sweets in the home was significantly associated with children\u27s consumption of various sweets. For every increase in keeping sweets at home, the odds of children consuming: • Chocolate and other candy increased by 67% (p \u3c 0.01) • Muffins/donuts increased by 40% (p \u3c 0.05) • Cookies, cakes, pies, and other desserts increased by 49% (p \u3c 0.01)https://oasis.library.unlv.edu/durep_lightning/1047/thumbnail.jp
The Influence of Money in Politics
No full textMoney plays a powerful role in shaping political outcomes by significantly influencing who gets elected and which policies are prioritized. Campaign financing, which includes donations from individuals, corporations, and Political Action Committees (PACs), often determines a candidate\u27s visibility, resources, and ability to compete effectively. Those with greater financial backing tend to dominate media coverage and reach more voters, which can tip the scales in elections.https://oasis.library.unlv.edu/durep_podium/1062/thumbnail.jp
Gambling-Related User-Generated Content: An In-Depth Analysis of Slot Machine Vlogs on YouTube
No full textThe growing popularity of social media platforms has transformed how gambling content reaches audiences, with gambling vlogs now attracting millions of viewers outside traditional marketing channels. Despite their reach and potential influence, these user-generated videos remain understudied in gambling research. This study sought to analyze slot machine vlogs by examining their portrayal of gambling experiences, assessing viewer engagement patterns, and identifying the video features associated with higher engagement metrics. Using a comprehensive mixed-methods approach, I analyzed 170 popular YouTube slot machine vlogs and 43,837 viewer comments through advanced analytical techniques. Latent Dirichlet Allocation topic modeling identified four themes in gambling portrayal, with betting strategies and game mechanics dominating the narratives. A targeted term detection approach found that responsible gambling (RG) messaging appeared in only 9.41% of videos, while binary logistic regression analyses indicated that these RG-inclusive videos were associated with higher engagement metrics. Viewer comment analysis using SentiStrength showed predominantly neutral-to-positive sentiment, and comment topic modeling uncovered five distinct engagement themes ranging from technical discussions to community building. The study contributes to gambling literature through its comprehensive analysis of an influential yet previously underexamined medium while developing methodological frameworks applicable to video content analysis in broader hospitality research. The findings offer actionable implications across the gambling ecosystem: content creators gain strategies for optimizing audience engagement, gambling operators receive guidance on partnership selection, and platforms obtain recommendations for developing policies that balance user engagement with RG practices
MFGAT: Map-Free Trajectory Prediction with Graph Attention Networks for Autonomous Vehicles
No full textAccurate trajectory prediction is a key component for ensuring safe and efficient navigation of autonomous vehicles in complex traffic scenarios. While traditional methods rely heavily on high-definition (HD) maps, these approaches face significant challenges, including high costs, limited availability, and susceptibility to rapid obsolescence. This thesis proposes an end-to-end, map-free trajectory prediction model that leverages Graph Attention Networks (GAT) to dynamically capture spatial-temporal interactions among road agents, eliminating the need for HD maps.The research introduces UNLVTraj, a novel LiDAR-based dataset collected around the University of Nevada, Las Vegas campus, specifically along Cottage Grove Street, Harmon Avenue, and Maryland Parkway. This dataset captures diverse traffic scenarios with annotated trajectories, addressing a gap in existing resources by providing realistic, campus-specific interactions for validation. The proposed model combines GAT with Temporal Convolutional Networks (TCN) and a sequence-to-sequence framework, enabling adaptive weighting of agent interactions to enhance prediction accuracy. Experimental results demonstrate the model’s effectiveness across different environments. On the ApolloScape benchmark, the model achieves a 5.98% reduction in Average Displacement Error (ADE) and a 6.76% reduction in Final Displacement Error (FDE) compared to baseline method. Evaluations on the UNLVTraj dataset further validate its robustness in predicting trajectories for heterogeneous agents, even in unstructured, map-free settings. By offering a scalable, cost-effective solution and a publicly available dataset, this work supports future research in map-free navigation
The Roles of OprF in Pseudomonas aeruginosa Biofilms
No full textMany bacteria form multicellular communities known as biofilms. Biofilms contain bacterial cells and a protective extracellular biofilm matrix. This matrix contains exopolysaccharides, extracellular DNA (eDNA), membrane vesicles, and proteins. The matrix proteins are far less characterized than other extracellular biofilm components. In biofilms formed by the model organism Pseudomonas aeruginosa, the protein OprF is abundant in the cellular outer membrane and the extracellular matrix. In my dissertation research, I have presented data supporting the hypothesis that the OprF protein significantly affects P. aeruginosa biofilms. By examining various strain backgrounds and the nutrient-dependent effects of glucose and sodium chloride, I demonstrate that the roles of OprF are condition-dependent. Furthermore, the data confirm that these effects are not due to OprF-dependent differences in the number or morphology of cells in P. aeruginosa biofilms, nor are the nutrient-dependent effects due to differences in media osmolarity or metal concentrations. The research highlights the impact of the OprF protein on late-stage static biofilms via the loss of eDNA from the biofilm matrix. In contrast, I clarify that levels of the P. aeruginosa exopolysaccharide Psl are unaffected by a loss of OprF, and that OprF-dependent biofilm defects are not affected by Pseudomonas Quinolone Signaling molecules. I hypothesize that OprF is impacting P. aeruginosa biofilm eDNA levels via two possible mechanisms: 1) by retaining eDNA in the matrix, or 2) by affecting intracellular pathways involved in cell lysis, which produces eDNA. Future transcriptomic analysis of P. aeruginosa biofilm cells with and without OprF, for which I have optimized RNA extraction, will help elucidate any intracellular effects of OprF
The Development of Violin Art in China and the Exchange of Eastern and Western Elements: A Case Study of Fritz Kreisler\u27s Tambourin Chinois
No full textThe Violin, often regarded as one of the most expressive and versatile instruments in the world, holds a central place in both Western and non-Western musical traditions. Its wide dynamic range, tonal flexibility, and unmatched capacity for nuanced expression have allowed it to transcend cultural boundaries and play a key role in the development of diverse musical genres. From classical symphonies and chamber music to folk, jazz, and even popular music, the violin\u27s distinctive voice can be heard shaping the sonic identity of cultures across the globe. In the context of Chinese music, the violin\u27s influence has grown significantly since its introduction to China in 1673, when it was introduced to China. Initially, Chinese composers and musicians primarily focused on replicating Western works, as the instrument was largely viewed through a Western classical lens. However, over time, with the dedication and innovation of numerous Chinese composers and performers, such as Li Zili (b.1938), Xiao Youmei (1884-1940), Ma Sicong (1912-1987) and Yang Baozhi (b. 1935), the violin has become deeply embedded in China\u27s own musical evolution. These pioneers began to create original violin works that reflected the distinctive elements of Chinese folk music, tonal systems, and performance practices, leading to the emergence of a uniquely Chinese violin repertoire. The development of this repertoire marked an important step in the violin\u27s localization, contributing greatly to the nationalization of violin artistry in China.As a core instrument in the Western classical tradition, the violin has evolved not only as a vehicle for virtuosic display but also as a conduit for artistic and cultural exchange. Its adaptability has facilitated the integration of various musical elements from around the world, particularly in the 20th and 21st centuries, with the development of violin artistry, an increasing number of Western composers have begun to infuse their compositions with non-Western musical elements. As the number of Chinese violin compositions grew, so did the interest of Western composers in the distinctive characteristics of Chinese musical idioms. Many Western composers began to incorporate elements of Chinese music into their violin works, such as pentatonic scales, Chinese melodic ornamentation, and unique timbral effects. Prominent examples include Gustav Mahler\u27s Das Lied von der Erde, where Mahler incorporates Chinese poetry and utilizes pentatonic scales to evoke Eastern aesthetics, and Fritz Kreisler\u27s Tambourin Chinois, which employs Chinese-inspired melodic motifs and rhythms to create an exotic soundscape. Furthermore, Chinese-American composers such as Chou Wenchung (1923-2019) and Tan Dun (b.1957) have been at the forefront of integrating Eastern musical elements into Western music. Chou Wen-chung, one of the earliest composers to introduce Eastern melodies and rhythms into contemporary Western music, is known for his works such as Landscapes (1949) and Eternal Pine (1948), which seamlessly blend Chinese musical concepts with Western compositional techniques. Similarly, Tan Dun, a prolific composer, has gained international recognition for his works that bridge Eastern and Western musical traditions. His Ghost Opera (1994) and Crouching Tiger, Hidden Dragon (2000) are prime examples of his unique approach to merging traditional Chinese instruments and musical elements with Western orchestral music. This exchange of ideas between Chinese and Western traditions has enriched the global violin repertoire, creating a new, hybrid musical language that is representative of deeper cross-cultural dialogue. The integration of Chinese musical elements in Western violin music not only highlights the versatility of the instrument but also fosters a greater appreciation for the cultural synthesis that can be achieved through music. Given this background, this paper will explore the utilization, integration, and performance techniques of Chinese musical elements in violin repertoire, examining how these elements have been adopted and adapted within both Chinese and Western musical contexts. A central focus will be on Fritz Kreisler\u27s Tambourin Chinois, a seminal work that exemplifies the incorporation of Chinese musical motifs into Western violin literature. By analyzing this piece, the study illustrates the ways in which Western composers have engaged with Chinese musical aesthetics, integrating pentatonic scales, modal harmonies, and characteristic rhythms into their compositions. The research highlights how the violin serves as a bridge, not only between musical traditions but also between cultures, fostering a deeper appreciation for the rich diversity of global music