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The loss of methyl bromide led to vegetable growers relying more heavily on herbicides to control weeds. Although herbicides can be effective, limited options in vegetable production challenge growers. Identifying new, effective tools to be applied over plastic mulch prior to planting for improved weed control with minimal crop injury would be beneficial. The objective of these experiments was to evaluate the persistence of preplant applications of glyphosate (1,125 or 2,250 g ae ha-1) plus 2,4-D (1,065 or 2,130 g ae ha-1) or dicamba (560 g ae ha-1) over plastic mulch using analytical techniques and subsequent squash and watermelon response. Glyphosate and 2,4-D were not analytically detected at damaging concentrations on plastic mulch when at least 3.5 cm of rainfall was received after application and before planting. Additionally, bioassay results for squash and watermelon supported analytical results with less than 10% visual injury for either crop, with no growth or yield suppression observed. In contrast, dicamba concentrations on plastic mulch, regardless of rainfall amount or time between application and planting, remained at damaging levels. Squash yields were reduced by dicamba applied 1 to 30 days before planting while watermelon was more resilient. 2,4-D plus glyphosate applied preplant over plastic mulch can provide an additional herbicide option for vegetable growers. Additional research is needed to understand the impact of residual activity of 2,4-D when transplants land directly in holes present in plastic mulch at the time of application. The relationship of dicamba with plastic mulch is complex as the herbicide cannot be easily removed by rainfall. Thus, dicamba should not be included in a weed management system in plasticulture vegetable production.
Pilot programs are integral to catalyzing and accelerating research at Clinical and Translational Science Award (CTSA) hubs. However, little has been published about the structure and operationalization of pilot programs or how they impact the translational research enterprise at CTSAs. The North Carolina Translational and Clinical Science Institute (NC TraCS), the CTSA hub at the University of North Carolina at Chapel Hill (UNC-CH) conducted an evaluation case study to describe the pilot program structure, assess process outcomes, and provide a framework for other institutions to utilize for the evaluation of their respective pilot programs.
We describe the operationalization of our pilot program, the evaluation framework utilized to evaluate the program, and how we analyzed available data to understand how our pilot funding opportunities were utilized by investigators. We calculated application volumes and funding rates by investigator position title and pilot application type. We also reviewed feedback provided by pilot Principal Investigators (PIs) to understand how many pilot projects were completed, NC TraCS service utilization, and barriers to research. Limited data on publications and subsequent funding was also reviewed.
Between 2009 and 2019 the NC TraCS Pilot Program received 2343 applications and funded 933 projects, ranging from $2000 to $100,000 in amount, with an overall funding rate of 39.8%. Utilization of NC TraCS services had positive impacts on both resubmission funding and project completion rates.
This process evaluation indicates that the program is being operationalized in a way that successfully fulfills the program mission while meeting the needs of a diverse group of researchers.
This work investigated the photophysical pathways for light absorption, charge generation, and charge separation in donor–acceptor nanoparticle blends of poly(3-hexylthiophene) and indene-C60-bisadduct. Optical modeling combined with steady-state and time-resolved optoelectronic characterization revealed that the nanoparticle blends experience a photocurrent limited to 60% of a bulk solution mixture. This discrepancy resulted from imperfect free charge generation inside the nanoparticles. High-resolution transmission electron microscopy and chemically resolved X-ray mapping showed that enhanced miscibility of materials did improve the donor–acceptor blending at the center of the nanoparticles; however, a residual shell of almost pure donor still restricted energy generation from these nanoparticles.
The Tennessee Department of Health (TDH) investigated a hepatitis A virus (HAV) outbreak to identify risk factors for infection and make prevention recommendations.
Healthcare workers (HCWs) or patients with laboratory-confirmed acute HAV infection during October 1, 2018–January 10, 2019.
HCWs with suspected or confirmed hepatitis A infections were interviewed to assess their exposures and activities. Patient medical records and hospital administrative records were reviewed to identify common exposures. We conducted a site investigation to assess knowledge of infection control practices among HCWs. Serum specimens from ill persons were tested for HAV RNA by polymerase chain reaction (PCR) and genotyped.
We identified 6 HCWs and 2 patients with laboratory-confirmed HAV infection. All cases likely resulted from exposure to a homeless patient with a history of recreational substance use and undiagnosed HAV infection. Breaches in hand hygiene and use of standard precautions were identified. HAV RNA was detected in 7 serum specimens and all belonged to an identical strain of HAV genotype 1b.
A hepatitis A outbreak among hospital patients and HCWs resulted from exposure to a single patient with undiagnosed HAV infection. Breakdowns in infection control practices contributed to the outbreak. The likelihood of nosocomial transmission can be reduced with proper hand hygiene, standard precautions, and routine disinfection. During community outbreaks, medical providers can better prevent ongoing transmission by including hepatitis A in the differential diagnosis among patients with a history of recreational substance use and homelessness.
Radiocarbon (14C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric 14C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international 14C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable 14C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the 14C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine 14C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.
Early researchers of radiocarbon levels in Southern Hemisphere tree rings identified a variable North-South hemispheric offset, necessitating construction of a separate radiocarbon calibration curve for the South. We present here SHCal20, a revised calibration curve from 0–55,000 cal BP, based upon SHCal13 and fortified by the addition of 14 new tree-ring data sets in the 2140–0, 3520–3453, 3608–3590 and 13,140–11,375 cal BP time intervals. We detail the statistical approaches used for curve construction and present recommendations for the use of the Northern Hemisphere curve (IntCal20), the Southern Hemisphere curve (SHCal20) and suggest where application of an equal mixture of the curves might be more appropriate. Using our Bayesian spline with errors-in-variables methodology, and based upon a comparison of Southern Hemisphere tree-ring data compared with contemporaneous Northern Hemisphere data, we estimate the mean Southern Hemisphere offset to be 36 ± 27 14C yrs older.
The scope and scale of wildlife crimes around the world have risen in intensity and complexity, yet current enforcement strategies have often not delivered desired effects on illegal activities, even within protected areas. Tackling the array of illegal activities by emphasizing law enforcement above other options is challenging and potentially unsustainable. We explored the potential for social norms, community regulations and socioeconomic factors to promote compliance with wildlife laws by interviewing 334 respondents in 28 villages that share boundaries with protected areas in Nigeria. Using an anonymous direct questioning approach, we recorded a high prevalence of non-compliance behaviours in all studied communities. Injunctive norms (i.e., perceptions of acceptable behaviour within a social group) significantly predicted compliance, as respondents with no complicit friends or family members were more likely to comply with wildlife regulations. Perceived likelihood of community-level sanctions played a more salient role than the fear of arrest by rangers in influencing compliance. In addition, non-compliance increased with number of dependents, but reduced with average monthly household income. Our study demonstrates that clear knowledge of the social norms that drive local behaviour as well as the authorities that enforce them is integral to understanding the forces that drive community involvement and participation in conservation. Incorporating local communities in planning enforcement interventions may help protect threatened species and landscapes.
To enhance the performance evaluation of Clinical and Translational Science Award (CTSA) hubs, we examined the utility of advanced bibliometric measures that go beyond simple publication counts to demonstrate the impact of translational research output.
The sampled data included North Carolina Translational and Clinical Science Institute (NC TraCS)-supported publications produced between September 2008 and March 2017. We adopted advanced bibliometric measures and a state-of-the-art bibliometric network analysis tool to assess research productivity, citation impact, the scope of research collaboration, and the clusters of research topics.
Totally, 754 NC TraCS-supported publications generated over 24,000 citation counts by April 2017 with an average of 33 cites per article. NC TraCS-supported research papers received more than twice as many cites per year as the average National Institute of Health-funded research publications from the same field and time. We identified the top productive researchers and their networks within the CTSA hub. Findings demonstrated the impact of NC TraCS in facilitating interdisciplinary collaborations within the CTSA hub and across the CTSA consortium and connecting researchers with right peers and organizations.
Both improved bibliometrics measures and bibliometric network analysis can bring new perspectives to CTSA evaluation via citation influence and the scope of research collaborations.
Shared patient–clinician decision-making is central to choosing between medical treatments. Decision support tools can have an important role to play in these decisions. We developed a decision support tool for deciding between nonsurgical treatment and surgical total knee replacement for patients with severe knee osteoarthritis. The tool aims to provide likely outcomes of alternative treatments based on predictive models using patient-specific characteristics. To make those models relevant to patients with knee osteoarthritis and their clinicians, we involved patients, family members, patient advocates, clinicians, and researchers as stakeholders in creating the models.
Stakeholders were recruited through local arthritis research, advocacy, and clinical organizations. After being provided with brief methodological education sessions, stakeholder views were solicited through quarterly patient or clinician stakeholder panel meetings and incorporated into all aspects of the project.
Participating in each aspect of the research from determining the outcomes of interest to providing input on the design of the user interface displaying outcome predications, 86% (12/14) of stakeholders remained engaged throughout the project. Stakeholder engagement ensured that the prediction models that form the basis of the Knee Osteoarthritis Mathematical Equipoise Tool and its user interface were relevant for patient–clinician shared decision-making.
Methodological research has the opportunity to benefit from stakeholder engagement by ensuring that the perspectives of those most impacted by the results are involved in study design and conduct. While additional planning and investments in maintaining stakeholder knowledge and trust may be needed, they are offset by the valuable insights gained.
Late Holocene sediment deposits in Pine Island Bay, West Antarctica, are hypothesized to be linked to intensive meltwater drainage during the retreat of the paleo-Pine Island Ice Stream after the Last Glacial Maximum. The uppermost sediment units show an abrupt transition from ice-proximal debris to a draped silt during the late Holocene, which is interpreted to coincide with rapid deglaciation. The small scale and fine sorting of the upper unit could be attributed to origins in subglacial meltwater; however the thickness and deposition rate for this unit imply punctuated- rather than continuous-deposition. This, combined with the deposit's location seaward of large, bedrock basins, has led to the interpretation of this unit as the result of subglacial lake outbursts in these basins. However, the fine-scale sorting of the silt unit is problematic for this energetic interpretation, which should mobilize and deposit a wider range of sediment sizes. To resolve this discrepancy, we present an alternative mechanism in which the silt was sorted by a distributed subglacial water system, stored in bedrock basins far inland of the grounding line, and subsequently eroded at higher flow speeds during retreat. We demonstrate that this mechanism is physically plausible given the subglacial conditions during the late Holocene. We hypothesize that similar silt units observed elsewhere in Antarctica downstream of bedrock basins could be the result of the same mechanism.
The theory of reflectance and emittance spectroscopy is based on the fundamental principles of radiative transfer (the propagation of energy in the form of electromagnetic radiation) in particulate media. This chapter outlines key models for radiative transfer in particulate media that can be forward-modeled to predict reflectance and emittance spectra or inverted to obtain the abundance of geologic materials from remote observations. The models are rooted in the optical properties of geologic materials, namely the complex index of refraction, and the scattering of light controlled by particulate texture, shape, and size. The chapter is divided into reflectance modeling and emittance modeling because of the key difference in the origin of the electromagnetic radiation: external to the grain’s surface and internal to the grain’s surface, though the principles are common across this division. The key models presented for reflectance spectroscopy are the Hapke model for scattering and reflectance and the Shkuratov model for reflectance. For emittance spectroscopy, the Hapke model forms the backbone upon which hybrid models incorporating Mie T-matrix concepts are integrated.
Bone healing is an important survival mechanism, allowing vertebrates to recover from injury and disease. Here we describe newly recognized paleopathologies in the hindlimbs of the early tetrapods Crassigyrinus scoticus and Eoherpeton watsoni from the early Carboniferous of Cowdenbeath, Scotland. These pathologies are among the oldest known instances of bone healing in tetrapod limb bones in the fossil record (about 325 Ma). X-ray microtomographic imaging of the internal bone structure of these lesions shows that they are characterized by a mass of trabecular bone separated from the shaft's trabeculae by a layer of cortical bone. We frame these paleopathologies in an evolutionary context, including additional data on bone healing and its pathways across extinct and extant sarcopterygians. These data allowed us to synthesize information on cell-mediated repair of bone and other mineralized tissues in all vertebrates, to reconstruct the evolutionary history of skeletal tissue repair mechanisms. We conclude that bone healing is ancestral for sarcopterygians. Furthermore, other mineralized tissues (aspidin and dentine) were also capable of healing and remodeling early in vertebrate evolution, suggesting that these repair mechanisms are synapomorphies of vertebrate mineralized tissues. The evidence for remodeling and healing in all of these tissues appears concurrently, so in addition to healing, these early vertebrates had the capacity to restore structure and strength by remodeling their skeletons. Healing appears to be an inherent property of these mineralized tissues, and its linkage to their remodeling capacity has previously been underappreciated.
Modern clientelist exchange is typically carried out by intermediaries—party activists, employers, local strongmen, traditional leaders, and the like. Politicians use such brokers to mobilize voters, yet little about their relative effectiveness is known. The authors argue that broker effectiveness depends on their leverage over clients and their ability to monitor voters. They apply their theoretical framework to compare two of the most common brokers worldwide, party activists and employers, arguing the latter enjoy numerous advantages along both dimensions. Using survey-based framing experiments in Venezuela and Russia, the authors find voters respond more strongly to turnout appeals from employers than from party activists. To demonstrate mechanisms, the article shows that vulnerability to job loss and embeddedness in workplace social networks make voters more responsive to clientelist mobilization by their bosses. The results shed light on the conditions most conducive to effective clientelism and highlight broker type as important for understanding why clientelism is prevalent in some countries but not others.
The results of Bayesian analysis using 43 new high-precision AMS radiocarbon dates on maize, faunal remains, and ceramic residues from 18 precontact Iroquoian village sites in Northern New York are presented. Once thought to span AD 1350–1500, the period of occupation suggested by the modeling is approximately AD 1450–1510. This late placement now makes clear that Iroquoians arrived in the region approximately 100 years later than previously thought. This result halves the time in which population growth and significant changes in settlement occurred. The new chronology allows us to better match these events within a broader Northeast temporal framework.
In preparation for a multisite antibiotic stewardship intervention, we assessed knowledge and attitudes toward management of asymptomatic bacteriuria (ASB) plus teamwork and safety climate among providers, nurses, and clinical nurse assistants (CNAs).
Prospective surveys during January–June 2018.
All acute and long-term care units of 4 Veterans’ Affairs facilities.
The survey instrument included 2 previously tested subcomponents: the Kicking CAUTI survey (ASB knowledge and attitudes) and the Safety Attitudes Questionnaire (SAQ).
A total of 534 surveys were completed, with an overall response rate of 65%. Cognitive biases impacting management of ASB were identified. For example, providers presented with a case scenario of an asymptomatic patient with a positive urine culture were more likely to give antibiotics if the organism was resistant to antibiotics. Additionally, more than 80% of both nurses and CNAs indicated that foul smell is an appropriate indication for a urine culture. We found significant interprofessional differences in teamwork and safety climate (defined as attitudes about issues relevant to patient safety), with CNAs having highest scores and resident physicians having the lowest scores on self-reported perceptions of teamwork and safety climates (P < .001). Among providers, higher safety-climate scores were significantly associated with appropriate risk perceptions related to ASB, whereas social norms concerning ASB management were correlated with higher teamwork climate ratings.
Our survey revealed substantial misunderstanding regarding management of ASB among providers, nurses, and CNAs. Educating and empowering these professionals to discourage unnecessary urine culturing and inappropriate antibiotic use will be key components of antibiotic stewardship efforts.
This research investigates two factors influencing the ability of tree-ring data to provide accurate 14C calibration information: the fitness and rigor of the statistical model used to combine the data into a curve; and the accuracy, precision and reproducibility of the component 14C data sets. It presents a new Bayesian spline method for calibration curve construction and tests it on extant and new Southern Hemisphere (SH) data sets (also examining their dendrochronology and pretreatment) for the post-Little Ice Age (LIA) interval AD 1500–1950. The new method of construction allows calculation of component data offsets, permitting identification of laboratory and geographic biases. Application of the new method to the 10 suitable SH 14C data sets suggests that individual offset ranges for component data sets appear to be in the region of ± 10 yr. Data sets with individual offsets larger than this need to be carefully assessed before selection for calibration purposes. We identify a potential geographical offset associated with the Southern Ocean (high latitude) Campbell Island data. We test the new methodology for wiggle-matching short tree-ring sequences and use an OxCal simulation to assess the likely precision obtainable by wiggle-matching in the post-LIA interval.
We consider peeling of an elastic sheet away from an elastic substrate through propagation of a fluid-filled crack along the interface between the two. The peeling is driven by a bending moment applied to the sheet and is resisted by viscous flow towards the crack tip and by the toughness of any bonding between the sheet and the substrate. Travelling-wave solutions are determined using lubrication theory coupled to the full equations of elasticity and fracture. The propagation speed
is the sheet’s thickness,
its plane-strain modulus,
the fluid viscosity,
the applied bending moment and
the sheet’s curvature due to bending; and the prefactor depends on the dimensionless toughness. If the toughness is small then there is a region of dry shear failure ahead of the fluid-filled region. The expressions for the propagation speed have been used to derive new similarity solutions for the spread of an axisymmetric fluid-filled blister in a variety of regimes: constant-flux injection resisted by elastohydrodynamics in the tip leads to spread proportional to
for peeling-by-bending, gravitational spreading and peeling-by-pulling, respectively.