Showing papers by "University of North Carolina at Wilmington published in 2021"

Comprehensive Stroke Care and Outcomes: Time for a Paradigm Shift.

Abstract: Worldwide, stroke is prevalent, costly, and disabling in >80 million survivors. The burden of stroke is increasing despite incredible progress and advancements in evidence-based acute care therapies and despite the substantial changes being made in acute care stroke systems, processes, and quality metrics. Although there has been increased global emphasis on the importance of postacute stroke care, stroke system changes have not expanded to include postacute care and outcome follow-up. Our objectives are to describe the gaps and challenges in postacute stroke care and suboptimal stroke outcomes; to report on stroke survivors' and caregivers' perceptions of current postacute stroke care and their call for improvements in follow-up services for recovery and secondary prevention; and, ultimately, to make the case that a paradigm shift is needed in the definition of comprehensive stroke care and the designation of Comprehensive Stroke Center. Three recommendations are made for a paradigm shift in comprehensive stroke care: (1) criteria should be established for designation of rehabilitation readiness for Comprehensive Stroke Centers, (2) The American Heart Association/American Stroke Association implement an expanded Get With The Guidelines-Stroke program and criteria for comprehensive stroke centers to be inclusive of rehabilitation readiness and measure outcomes at 90 days, and (3) a public health campaign should be launched to offer hopeful and actionable messaging for secondary prevention and recovery of function and health. Now is the time to honor the patients' and caregivers' strongest ask: better access and improved secondary prevention, stroke rehabilitation, and personalized care.

Overcoming Barriers to Technology Adoption When Fostering Entrepreneurship Among the Poor: The Role of Technology and Digital Literacy

Abstract: The adoption of new technologies can contribute to both efficiency and effectiveness and is a key source of long-term competitive advantage in entrepreneurial ventures. This is particularly relevant for poverty entrepreneurs. However, the literature on technology adoption and use in the poverty context is sparse, and is predominantly focused on developing economies. The current article seeks to address these shortcomings. We identify critical areas of typical ventures launched by the poor that are affected by technology. Attention is devoted to understanding technology as a product versus a process and what this distinction means for poverty entrepreneurs. We introduce a conceptual framework linking technology and digital literacy, technology adoption, and absorptive capacity to venture inputs and outputs. Dynamic interactions among these variables are explored. Implications for theory development and management practice, together with recommendations for future research, are provided.

Reference genome and demographic history of the most endangered marine mammal, the vaquita.

Abstract: The vaquita is the most critically endangered marine mammal, with fewer than 19 remaining in the wild. First described in 1958, the vaquita has been in rapid decline for more than 20 years resulting from inadvertent deaths due to the increasing use of large-mesh gillnets. To understand the evolutionary and demographic history of the vaquita, we used combined long-read sequencing and long-range scaffolding methods with long- and short-read RNA sequencing to generate a near error-free annotated reference genome assembly from cell lines derived from a female individual. The genome assembly consists of 99.92% of the assembled sequence contained in 21 nearly gapless chromosome-length autosome scaffolds and the X-chromosome scaffold, with a scaffold N50 of 115 Mb. Genome-wide heterozygosity is the lowest (0.01%) of any mammalian species analysed to date, but heterozygosity is evenly distributed across the chromosomes, consistent with long-term small population size at genetic equilibrium, rather than low diversity resulting from a recent population bottleneck or inbreeding. Historical demography of the vaquita indicates long-term population stability at less than 5,000 (Ne) for over 200,000 years. Together, these analyses indicate that the vaquita genome has had ample opportunity to purge highly deleterious alleles and potentially maintain diversity necessary for population health.

The recent emergence of Arctic Amplification

Abstract: Arctic Amplification is robustly seen in climate model simulations of future warming and in the paleoclimate record. Here, we show that in the instrumental record Arctic Amplification is only a rec...

A nuclear phylogenomic study of the angiosperm order Myrtales, exploring the potential and limitations of the universal Angiosperms353 probe set

Abstract: Premise To further advance the understanding of the species-rich, economically and ecologically important angiosperm order Myrtales in the rosid clade, comprising nine families, approximately 400 genera and almost 14,000 species occurring on all continents (except Antarctica), we tested the Angiosperms353 probe kit. Methods We combined high-throughput sequencing and target enrichment with the Angiosperms353 probe kit to evaluate a sample of 485 species across 305 genera (76% of all genera in the order). Results Results provide the most comprehensive phylogenetic hypothesis for the order to date. Relationships at all ranks, such as the relationship of the early-diverging families, often reflect previous studies, but gene conflict is evident, and relationships previously found to be uncertain often remain so. Technical considerations for processing HTS data are also discussed. Conclusions High-throughput sequencing and the Angiosperms353 probe kit are powerful tools for phylogenomic analysis, but better understanding of the genetic data available is required to identify genes and gene trees that account for likely incomplete lineage sorting and/or hybridization events.

The GlueX beamline and detector

Abstract: The GlueX experiment at Jefferson Lab has been designed to study photoproduction reactions with a 9-GeV linearly polarized photon beam. The energy and arrival time of beam photons are tagged using a scintillator hodoscope and a scintillating fiber array. The photon flux is determined using a pair spectrometer, while the linear polarization of the photon beam is determined using a polarimeter based on triplet photoproduction. Charged-particle tracks from interactions in the central target are analyzed in a solenoidal field using a central straw-tube drift chamber and six packages of planar chambers with cathode strips and drift wires. Electromagnetic showers are reconstructed in a cylindrical scintillating fiber calorimeter inside the magnet and a lead-glass array downstream. Charged particle identification is achieved by measuring energy loss in the wire chambers and using the flight time of particles between the target and detectors outside the magnet. The signals from all detectors are recorded with flash ADCs and/or pipeline TDCs into memories allowing trigger decisions with a latency of 3.3 μ s . The detector operates routinely at trigger rates of 40 kHz and data rates of 600 megabytes per second. We describe the photon beam, the GlueX detector components, electronics, data-acquisition and monitoring systems, and the performance of the experiment during the first three years of operation.

Rapid protein evolution, organellar reductions, and invasive intronic elements in the marine aerobic parasite dinoflagellate Amoebophrya spp

Abstract: Dinoflagellates are aquatic protists particularly widespread in the oceans worldwide. Some are responsible for toxic blooms while others live in symbiotic relationships, either as mutualistic symbionts in corals or as parasites infecting other protists and animals. Dinoflagellates harbor atypically large genomes (~ 3 to 250 Gb), with gene organization and gene expression patterns very different from closely related apicomplexan parasites. Here we sequenced and analyzed the genomes of two early-diverging and co-occurring parasitic dinoflagellate Amoebophrya strains, to shed light on the emergence of such atypical genomic features, dinoflagellate evolution, and host specialization. We sequenced, assembled, and annotated high-quality genomes for two Amoebophrya strains (A25 and A120), using a combination of Illumina paired-end short-read and Oxford Nanopore Technology (ONT) MinION long-read sequencing approaches. We found a small number of transposable elements, along with short introns and intergenic regions, and a limited number of gene families, together contribute to the compactness of the Amoebophrya genomes, a feature potentially linked with parasitism. While the majority of Amoebophrya proteins (63.7% of A25 and 59.3% of A120) had no functional assignment, we found many orthologs shared with Dinophyceae. Our analyses revealed a strong tendency for genes encoded by unidirectional clusters and high levels of synteny conservation between the two genomes despite low interspecific protein sequence similarity, suggesting rapid protein evolution. Most strikingly, we identified a large portion of non-canonical introns, including repeated introns, displaying a broad variability of associated splicing motifs never observed among eukaryotes. Those introner elements appear to have the capacity to spread over their respective genomes in a manner similar to transposable elements. Finally, we confirmed the reduction of organelles observed in Amoebophrya spp., i.e., loss of the plastid, potential loss of a mitochondrial genome and functions. These results expand the range of atypical genome features found in basal dinoflagellates and raise questions regarding speciation and the evolutionary mechanisms at play while parastitism was selected for in this particular unicellular lineage.

Modelling Tourism Resilience in Small Island States: A Tale of Two Countries

Abstract: The rising incidence and consequences of natural disasters, global economic crises, climate change, and socio-political upheavals have raised interest in resilience, particularly in small island ec...

Review of Methods to Equate Target Sets in the Adapted Alternating Treatments Design.

Abstract: The adapted alternating treatments design is a commonly used experimental design in skill acquisition research. This design allows for the evaluation of two or more independent variables on responding to unique target sets. Equating target sets is necessary to ensure a valid comparison of the independent variables. To date, there is little guidance on best practice when equating target sets and it is unclear how researchers have done so previously. We reviewed the reported methods used to equate target sets in articles published using the adapted alternating treatments design in five behavior-analytic journals. Just over half of the studies published using the adapted alternating treatments design reported any method to equate target sets and the methods varied considerably. Alternative methods, such as random assignment, were prevalent. Considerations for best practice and avenues for future research are discussed.

An Efficient WSN Based Solution for Border Surveillance

Abstract: Since a long time, the integrity of physical borders is seen as a challenging concern. Indeed, governments have to facilitate travelling and trade so that economies continue to grow while preventing the entry of dangerous entities. To this aim, several conventional techniques were enforced to secure borders in the recent past. However, due to the immensity of the area to be monitored, such solutions require an intensive human involvement and high maintenance costs. This advocated to use new technologies, such as Wireless Sensor Networks (WSN), to reduce the costs and improve the efficiency of the border surveillance system. Although using and combining these technologies has been already addressed in different existing solutions, it still some key points to be considered like energy efficiency, load balancing, and redundancy elimination. In this paper, we first propose a multilayer hybrid architecture based on cameras, scalar sensors, radars, and UAVs to design a border surveillance system. Then, a detailed deployment strategy is discussed. Finally, an activation scheduling strategy based on load balancing and energy saving is addressed. The simulation results show that our solution could not only detect the intrusion in border areas, but also outperforms the other solutions by managing efficiently the network and extending its lifetime.

Punctuated Orogeny During the Assembly of Asia: Tectonostratigraphic Evolution of the North China Craton and the Qilian Shan From the Paleoproterozoic to Early Paleozoic

Abstract: The assembling of the Eurasian continent occurred from the Proterozoic to the Mesozoic over a time span of nearly one billion years (Scotese & McKerrow, 1990; Şengör & Natal'in, 1996; Sone & Metcalfe, 2008; Yin & Nie, 1996). It was accomplished primarily by the closure of the Paleo-Asian and Tethyan ocean systems, involving cratonal blocks separated from the supercontinents Columbia, Rodinia, and Pangea (e.g., Badarch et al., 2002; Biske & Seltmann, 2010; Heubeck, 2001; Kusky et al., 2007; S. Li et al., 2018; Rogers & Santosh, 2002; Şengör & Natal'in, 1996; Stampfli & Borel, 2002; C. Wu et al., 2016a; Yin & Nie, 1996; G. C. Zhao et al., 2018; Zonenshain et al., 1990; Zuza & Yin, 2017) (Figure 1). The Paleo-Asian and the Tethyan oceanic domains are separated by the Tarim and North China cratons whose geologic histories are critical for deciphering the interactions of the two orogenic systems to the north and south. A major obstacle for establishing the geologic history of Tarim and North China cratons is that the two tectonic entities are currently bounded by Cenozoic structures along the southern margin of the Tian Shan and the northern margin of the Tibetan plateau (Figure 1). These structures have either reactivated or strongly modified the earlier tectonic configurations of the region (e.g., Yin & Nie, 1996). For example, Cenozoic structures that bound the southern margin of Tarim and North China cratons overprinted Mesozoic extensional basins (X. Chen et al., 2003; Vincent & Allen, 1999), an early Paleozoic arc-continent collision system (e.g., S. Song Abstract The Proterozoic-Phanerozoic evolution of the Tarim and North China cratons is integral to the construction of the Eurasian continent. Throughout the Paleozoic, these continents were bound by the Paleo-Asian and Tethyan Oceans to the north and south, respectively, and, thus, their paleogeography is critical to reconstructions of the oceanic domains. Specifically, it remains uncertain whether the Tarim and North China cratons were contiguous during the Paleozoic. Geologic observations from the Qilian Shan and Longshou Shan of western China provide valuable information regarding the paleotectonic relationships of these continents. Here we present detailed field, geochronological, and geochemical observations from key locations in the Qilian Shan and Longshou Shan to decipher complex relationships between the Kunlun-Qaidam, North China, and Tarim continents. Paleoproterozoic deformation might have been associated with the northern North China orogen, whereas a Neoproterozoic collisional orogen occurred between the Kunlun-Qaidam-South Tarim and the North China-North Tarim. Subsequent late Neoproterozoic rifting led to the opening of the Qilian ocean as an embayed marginal sea, and the PaleoAsian Ocean developed along the northern margin of the North China craton. South-dipping subduction, arc magmatism, slab rollback, and convergence between Kunlun-Qaidam and North China continued throughout the Early Silurian, which were recorded in the Qilian Shan and Longshou Shan regions. Our updated geotectonic framework requires reevaluation of previously published paleogeographic models, including ones that suggest the North China craton was affixed to Gondwana in the early Paleozoic. It is further considered a possible connection between the North China and southern Africa at ca. 2.05 Ga.

Association of Heavy Drinking With Deviant Fiber Tract Development in Frontal Brain Systems in Adolescents.

Abstract: Importance Maturation of white matter fiber systems subserves cognitive, behavioral, emotional, and motor development during adolescence. Hazardous drinking during this active neurodevelopmental period may alter the trajectory of white matter microstructural development, potentially increasing risk for developing alcohol-related dysfunction and alcohol use disorder in adulthood. Objective To identify disrupted adolescent microstructural brain development linked to drinking onset and to assess whether the disruption is more pronounced in younger rather than older adolescents. Design, Setting, and Participants This case-control study, conducted from January 13, 2013, to January 15, 2019, consisted of an analysis of 451 participants from the National Consortium on Alcohol and Neurodevelopment in Adolescence cohort. Participants were aged 12 to 21 years at baseline and had at least 2 usable magnetic resonance diffusion tensor imaging (DTI) scans and up to 5 examination visits spanning 4 years. Participants with a youth-adjusted Cahalan score of 0 were labeled as no-to-low drinkers; those with a score of greater than 1 for at least 2 consecutive visits were labeled as heavy drinkers. Exploratory analysis was conducted between no-to-low and heavy drinkers. A between-group analysis was conducted between age- and sex-matched youths, and a within-participant analysis was performed before and after drinking. Exposures Self-reported alcohol consumption in the past year summarized by categorical drinking levels. Main Outcomes and Measures Diffusion tensor imaging measurement of fractional anisotropy (FA) in the whole brain and fiber systems quantifying the developmental change of each participant as a slope. Results Analysis of whole-brain FA of 451 adolescents included 291 (64.5%) no-to-low drinkers and 160 (35.5%) heavy drinkers who indicated the potential for a deleterious association of alcohol with microstructural development. Among the no-to-low drinkers, 142 (48.4%) were boys with mean (SD) age of 16.5 (2.2) years and 149 (51.2%) were girls with mean (SD) age of 16.5 (2.1) years and 192 (66.0%) were White participants. Among the heavy drinkers, 86 (53.8%) were boys with mean (SD) age of 20.1 (1.5) years and 74 (46.3%) were girls with mean (SD) age of 20.5 (2.0) years and 142 (88.8%) were White participants. A group analysis revealed FA reduction in heavy-drinking youth compared with age- and sex-matched controls (t154 = –2.7,P = .008). The slope of this reduction correlated with log of days of drinking since the baseline visit (r156 = –0.21, 2-tailedP = .008). A within-participant analysis contrasting developmental trajectories of youths before and after they initiated heavy drinking supported the prediction that drinking onset was associated with and potentially preceded disrupted white matter integrity. Age-alcohol interactions (t152 = 3.0,P = .004) observed for the FA slopes indicated that the alcohol-associated disruption was greater in younger than older adolescents and was most pronounced in the genu and body of the corpus callosum, regions known to continue developing throughout adolescence. Conclusions and Relevance This case-control study of adolescents found a deleterious association of alcohol use with white matter microstructural integrity. These findings support the concept of heightened vulnerability to environmental agents, including alcohol, associated with attenuated development of major white matter tracts in early adolescence.

Anxiety, job satisfaction, supervisor support and turnover intentions of mid-career nurses: A structural equation model analysis

Abstract: Aims To explore the effects of four predictors of anxiety (work constraints, work/family conflict, verbal abuse and negative team orientation) among nurses and their subsequent effects on job satisfaction and turnover intentions; and to examine the moderating effect of supervisor support on the relationship between job satisfaction and turnover intentions. Background Work-related anxiety is a well-known predictor of employee burnout. Research suggests the prevalence of stress in the workplace varies by occupation, with stress among nurses one of the highest. Methods We employed data from the 2015 national survey of licensed registered nurses (n=1,080). We assessed the conceptual model using partial least squares structural equation modeling (PLS-SEM). Results Work constraints, work/family conflict, and negative team orientation lead to anxiety, which diminished job satisfaction and ultimately increased turnover intentions. Supervisor support weakened the job dissatisfaction-turnover relationship. Conclusions These findings suggest that the common experiences reported by health care professionals lead to anxiety and ultimately turnover intentions and emphasize the role of supervisor support. Implications for nursing management The supervisor's role is crucial to the implications of workplace-generated anxiety for nurse job satisfaction and turnover intentions. As such, nurse managers need to develop tangible strategies to help nurses navigate these contextual constraints.

How to identify win–win interventions that benefit human health and conservation

Abstract: To reach the Sustainable Development Goals, we may need to act on synergies between some targets while mediating trade-offs between other targets. But what, exactly, are synergies and trade-offs, and how are they related to other outcomes, such as ‘win–win’ solutions? Finding limited guidance in the existing literature, we developed an operational method for distinguishing win–wins from eight other possible dual outcomes (lose–lose, lose–neutral and so on). Using examples related to human health and conservation, we illustrate how interdisciplinary problem-solvers can use this framework to assess relationships among targets and compare multi-target interventions that affect people and nature. Reaching the Sustainable Development Goals requires recognizing trade-offs and synergies among targets. Focusing on conservation and human health, this Perspective suggests how to productively distinguish win–wins from other outcomes.

Role of silicon in the development of complex crystal shapes in coccolithophores.

Abstract: The development of calcification by the coccolithophores had a profound impact on ocean carbon cycling, but the evolutionary steps leading to the formation of these complex biomineralized structures are not clear. Heterococcoliths consisting of intricately shaped calcite crystals are formed intracellularly by the diploid life cycle phase. Holococcoliths consisting of simple rhombic crystals can be produced by the haploid life cycle stage but are thought to be formed extracellularly, representing an independent evolutionary origin of calcification. We use advanced microscopy techniques to determine the nature of coccolith formation and complex crystal formation in coccolithophore life cycle stages. We find that holococcoliths are formed in intracellular compartments in a similar manner to heterococcoliths. However, we show that silicon is not required for holococcolith formation and that the requirement for silicon in certain coccolithophore species relates specifically to the process of crystal morphogenesis in heterococcoliths. We therefore propose an evolutionary scheme in which the lower complexity holococcoliths represent an ancestral form of calcification in coccolithophores. The subsequent recruitment of a silicon-dependent mechanism for crystal morphogenesis in the diploid life cycle stage led to the emergence of the intricately shaped heterococcoliths, enabling the formation of the elaborate coccospheres that underpin the ecological success of coccolithophores.

Impacts of tourism on support for conservation, local livelihoods, and community resilience around Maasai Mara National Reserve, Kenya

Abstract: The tourism enterprise-based approach to conservation can diversify livelihood opportunities in and around protected areas while incentivizing conservation support and building community resilience...

Understanding how and when personal values foster entrepreneurial behavior: A humane perspective

Abstract: This study aims to examine the role of entrepreneurial intentions and motivations in the interplay between humane-oriented personal values and entrepreneurial behavior. Using data from 593 individu...

Evidence That Microorganisms at the Animal-Water Interface Drive Sea Star Wasting Disease.

Abstract: Sea star wasting (SSW) disease describes a condition affecting asteroids that resulted in significant Northeastern Pacific population decline following a mass mortality event in 2013. The etiology of SSW is unresolved. We hypothesized that SSW is a sequela of microbial organic matter remineralization near respiratory surfaces, one consequence of which may be limited O2 availability at the animal-water interface. Microbial assemblages inhabiting tissues and at the asteroid-water interface bore signatures of copiotroph proliferation before SSW onset, followed by the appearance of putatively facultative and strictly anaerobic taxa at the time of lesion genesis and as animals died. SSW lesions were induced in Pisaster ochraceus by enrichment with a variety of organic matter (OM) sources. These results together illustrate that depleted O2 conditions at the animal-water interface may be established by heterotrophic microbial activity in response to organic matter loading. SSW was also induced by modestly (∼39%) depleted O2 conditions in aquaria, suggesting that small perturbations in dissolved O2 may exacerbate the condition. SSW susceptibility between species was significantly and positively correlated with surface rugosity, a key determinant of diffusive boundary layer thickness. Tissues of SSW-affected individuals collected in 2013-2014 bore δ15N signatures reflecting anaerobic processes, which suggests that this phenomenon may have affected asteroids during mass mortality at the time. The impacts of enhanced microbial activity and subsequent O2 diffusion limitation may be more pronounced under higher temperatures due to lower O2 solubility, in more rugose asteroid species due to restricted hydrodynamic flow, and in larger specimens due to their lower surface area to volume ratios which affects diffusive respiratory potential.

Accommodation of India–Asia convergence via strike-slip faulting and block rotation in the Qilian Shan fold–thrust belt, northern margin of the Tibetan Plateau

Abstract: Existing models of intracontinental deformation have focused on plate-like rigid body motion v. viscous-flow-like distributed deformation. To elucidate how plate convergence is accommodated by intracontinental strike-slip faulting and block rotation within a fold–thrust belt, we examine the Cenozoic structural framework of the central Qilian Shan of northeastern Tibet, where the NW-striking, right-slip Elashan and Riyueshan faults terminate at the WNW-striking, left-slip Haiyuan and Kunlun faults. Field- and satellite-based observations of discrete right-slip fault segments, releasing bends, horsetail termination splays and off-fault normal faulting suggest that the right-slip faults accommodate block rotation and distributed west–east crustal stretching between the Haiyuan and Kunlun faults. Luminescence dating of offset terrace risers along the Riyueshan fault yields a Quaternary slip rate of c. 1.1 mm a−1, which is similar to previous estimates. By integrating our results with regional deformation constraints, we propose that the pattern of Cenozoic deformation in northeastern Tibet is compatible with west–east crustal stretching/lateral displacement, non-rigid off-fault deformation and broad clockwise rotation and bookshelf faulting, which together accommodate NE–SW India–Asia convergence. In this model, the faults represent strain localization that approximates continuum deformation during regional clockwise lithospheric flow against the rigid Eurasian continent. Supplementary material: Luminescence dating procedures and protocols is available at https://doi.org/10.17605/OSF.IO/CR9MN Thematic collection: This article is part of the Fold-and-thrust belts and associated basins collection available at: https://www.lyellcollection.org/cc/fold-and-thrust-belts

Deep Learning Techniques for Behavioral Malware Analysis in Cloud IaaS

Abstract: This chapter focuses on online malware detection techniques in cloud IaaS using machine learning and discusses comparative analysis on the performance metrics of various deep learning models.

Low bee visitation rates explain pollinator shifts to vertebrates in tropical mountains.

Abstract: Evolutionary shifts from bee to vertebrate pollination are common in tropical mountains. Reduction in bee pollination efficiency under adverse montane weather conditions was proposed to drive these shifts. Although pollinator shifts are central to the evolution and diversification of angiosperms, we lack experimental evidence of the ecological processes underlying such shifts. Here, we combine phylogenetic and distributional data for 138 species of the Neotropical plant tribe Merianieae (Melastomataceae) with pollinator observations of 11 and field pollination experiments of six species to test whether the mountain environment may indeed drive such shifts. We demonstrate that shifts from bee to vertebrate pollination coincided with occurrence at high elevations. We show that vertebrates were highly efficient pollinators even under the harsh environmental conditions of tropical mountains, whereas bee pollination efficiency was lowered significantly through reductions in flower visitation rates. Furthermore, we show that pollinator shifts in Merianieae coincided with the final phases of the Andean uplift and were contingent on adaptive floral trait changes to alternative rewards and mechanisms facilitating pollen dispersal. Our results provide evidence that abiotic environmental conditions (i.e. mountain climate) may indeed reduce the efficiency of a plant clade's ancestral pollinator group and correlate with shifts to more efficient new pollinators.

Late Mesozoic–Cenozoic cooling history of the northeastern Tibetan Plateau and its foreland derived from low-temperature thermochronology

Abstract: The growth history and formation mechanisms of the Cenozoic Tibetan Plateau are the subject of an intense debate with important implications for understanding the kinematics and dynamics of large-scale intracontinental deformation. Better constraints on the uplift and deformation history across the northern plateau are necessary to address how the Tibetan Plateau was constructed. To this end, we present updated field observations coupled with low-temperature thermochronology from the Qaidam basin in the south to the Qilian Shan foreland in the north. Our results show that the region experienced a late Mesozoic cooling event that is interpreted as a result of tectonic deformation prior to the India-Asia collision. Our results also reveal the onset of renewed cooling in the Eocene in the Qilian Shan region along the northern margin of the Tibetan Plateau, which we interpret to indicate the timing of initial thrusting and plateau formation along the plateau margin. The interpreted Eocene thrusting in the Qilian Shan predates Cenozoic thrust belts to the south (e.g., the Eastern Kunlun Range), which supports out-ofsequence rather than northward-migrating thrust belt development. The early Cenozoic deformation exploited the south-dipping early Paleozoic Qilian suture zone as indicated by our field mapping and the existing geophysical data. In the Miocene, strike-slip faulting was initiated along segments of the older Paleozoic suture zones in northern Tibet, which led to the development of the Kunlun and Haiyuan left-slip transpressional systems. Late Miocene deformation and uplift of the Hexi corridor and Longshou Shan directly north of the Qilian Shan thrust belt represent the most recent phase of outward plateau growth.

Atmospheric Deposition and Annual Flux of Legacy Perfluoroalkyl Substances and Replacement Perfluoroalkyl Ether Carboxylic Acids in Wilmington, NC, USA

Abstract: Wet deposition and dry deposition of legacy per- and polyfluoroalkyl substances (PFAS) and perfluoroalkyl ether carboxylic acids (PFECAs) were assessed on the southeastern coast of the United States, specifically, in Wilmington, NC, which is located 110 km from a fluorochemical manufacturer. Analytes were quantified by liquid chromatography coupled to electrospray ionization with triple-quadrupole mass spectrometry. Total concentrations of six PFAS compounds ranged from below the method quantification limit to 110 ng L–¹ by wet deposition, and total fluxes of 0.3–29 ng m–² day–¹ by dry deposition were found. The estimated annual flux of all six PFAS was 30 μg m–² by wet deposition and 1.4 μg m–² by dry deposition, indicating that PFAS are more effectively removed from the atmosphere by wet deposition. There was a significant rainout/washout effect observed in our data, but there was no impact of the origin of the air mass on concentration or flux, suggesting that the incorporation of PFAS into rainwater is a relatively local phenomenon. This study shows the first direct evidence of PFECAs in wet and dry deposition. The data suggest that the particle-bound and gas-phase PFAS that may have undergone long-range transport can be incorporated into raindrops and removed rapidly.

Sensitivity of sand lance to shifting prey and hydrography indicates forthcoming change to the northeast US shelf forage fish complex

Abstract: Northern sand lance (Ammodytes dubius) and Atlantic herring (Clupea harengus) represent the dominant lipid-rich forage fish species throughout the Northeast US shelf and are critical prey for numerous top predators. However, unlike Atlantic herring, there is little research on sand lance or information about drivers of their abundance. We use intra-annual measurements of sand lance diet, growth, and condition to explain annual variability in sand lance abundance on the Northeast US Shelf. Our observations indicate that northern sand lance feed, grow, and accumulate lipids in the late winter through summer, predominantly consuming the copepod Calanus finmarchicus. Sand lance then cease feeding, utilize lipids, and begin gonad development in the fall. We show that the abundance of C. finmarchicus influences sand lance parental condition and recruitment. Atlantic herring can mute this effect through intra-guild predation. Hydrography further impacts sand lance abundance as increases in warm slope water decrease overwinter survival of reproductive adults. The predicted changes to these drivers indicate that sand lance will no longer be able to fill the role of lipid-rich forage during times of low Atlantic herring abundance—changing the Northeast US shelf forage fish complex by the end of the century.

Instructor Social Presence and Connectedness in a Quick Shift from Face-to-Face to Online Instruction

Abstract: During the first weeks of the COVID-19 pandemic, instructors at a southeastern university had one week to convert their current face-to-face courses to an online format, under a time frame that did not allow for a “well-designed” online course. The current study investigates how some instructors were able to maintain social presence in the transition to the online environment, and the instructional practices they used to support those continued connections. In a cross-sectional survey of undergraduate and graduate students (N = 432 ) conducted during the last week of the Spring 2020 semester, we asked students to focus on a class that was successful in keeping them in touch with their instructor, content, and peers . Analyses of the data revealed four major themes: connectedness, instructor responsiveness and coaching, online learning best practices such as chunking materials, and empathic facilitation.