8,336 research outputs found
MODELING ALTERNATIVE POLICIES FOR GHG MITIGATION FROM FORESTRY AND AGRICULTURE
A key consideration for development of energy and climate policy affecting the forestry and agricultural sectors is that the selection of specific mechanisms implemented to achieve bioenergy production and/or greenhouse gas (GHG) mitigation targets may have substantial effects on landowner incentives to adopt alternative practices. For instance, the prices of allowances and offsets are expected to diverge under some policies being considered where there is a binding cap on the quantity of offsets from the agricultural and forest sectors. In addition, provisions that limit or exclude specific practices from receiving carbon payments will affect the quantity and cost of GHG mitigation opportunities available. In this study, the recently updated Forest and Agriculture Sector Optimization Model with GHGs (FASOMGHG) was used to estimate GHG mitigation potential for private land in the contiguous U.S. under a variety of GHG price policies. Model scenarios suggest that U.S. forestry and agriculture could provide mitigation of 200 – 1000 megatons carbon dioxide equivalent per year (Mt CO2e/year) at carbon prices of 50/tCO2e. Binding limits on offsets have increasingly large effects on both the total magnitude and distribution of GHG mitigation across options over time. In addition, discounting or excluding payments for forest sinks can reduce annualized land-based mitigation potential 37-90 percent relative to the full eligibility scenario whereas discounting or excluding agricultural practices reduces mitigation potential by less than 10 percent.Climate policy, energy policy, FASOMGHG, GHG mitigation, Agricultural and Food Policy, Environmental Economics and Policy, Resource /Energy Economics and Policy, C61, Q42, Q54,
Assessing adolescents' critical health literacy: How is trust in government leadership associated with knowledge of COVID-19?
This study explored relations between COVID-19 news source, trust in COVID-19 information source, and COVID-19 health literacy in 194 STEM-oriented adolescents and young adults from the US and the UK. Analyses suggest that adolescents use both traditional news (e.g., TV or newspapers) and social media news to acquire information about COVID-19 and have average levels of COVID-19 health literacy. Hierarchical linear regression analyses suggest that the association between traditional news media and COVID-19 health literacy depends on participants' level of trust in their government leader. For youth in both the US and the UK who used traditional media for information about COVID-19 and who have higher trust in their respective government leader (i.e., former US President Donald Trump and UK Prime Minister Boris Johnson) had lower COVID-19 health literacy. Results highlight how youth are learning about the pandemic and the importance of not only considering their information source, but also their levels of trust in their government leaders
Using highly variable warfarin dosing to identify patients at risk for adverse events
<p>Abstract</p> <p>Background</p> <p>Patients who receive highly variable doses of warfarin may be at risk for poor anticoagulation control and adverse events. However, we lack a system to identify patients with the highest dose variability. Our objectives were to develop a scoring system to identify patients with high dose variability, and to validate this new measure by demonstrating that patients so identified have poor anticoagulation control and higher rates of adverse events (criterion validity).</p> <p>Methods</p> <p>We used a database of over 4, 000 patients who received oral anticoagulation in community practice between 2000-2002. We reviewed the charts of 168 patients with large warfarin dose variation and agreed on 18 risk factor definitions for high dose variability. We identified 109 patients with the highest dose variability (cases), as measured by coefficient of variation (CoV, SD/mean). We matched each case to two controls with low dose variability. Then, we examined all 327 charts, blinded to case/control status, to identify the presence or absence of the 18 risk factors for dose variability. We performed a multivariable analysis to identify independent predictors of high CoV. We also compared anticoagulation control, as measured by percent time in therapeutic range (TTR), and rates of adverse events between groups.</p> <p>Results</p> <p>CoV corresponded with other measures of anticoagulation control. TTR was 53% among cases and 79% among controls (p < 0.001). CoV also predicted adverse events. Six cases experienced a major hemorrhage versus 1 control (p < 0.001) and 3 cases had a thromboembolic event versus 0 control patients (p = 0.04). Independent predictors of high dose variability included hospitalization (OR = 21.3), decreased oral intake (OR = 12.2), use of systemic steroids (OR = 6.1), acetaminophen (OR = 4.0) and antibiotics (OR = 2.7; p < 0.05 for all).</p> <p>Conclusion</p> <p>CoV can be used to identify patients at risk for poor anticoagulation control and adverse events. This new measure has the potential to identify patients at high risk before they suffer adverse events.</p
Ice nucleation and overseeding of ice in volcanic clouds
Water is the dominant component of volcanic gas emissions, and water phase transformations, including the formation of ice, can be significant in the dynamics of volcanic clouds. The effectiveness of volcanic ash particles as ice-forming nuclei (IN) is poorly understood and the sparse data that exist for volcanic ash IN have been interpreted in the context of meteorological, rather than volcanic clouds. In this study, single-particle freezing experiments were carried out to investigate the effect of ash particle composition and surface area on water drop freezing temperature. Measured freezing temperatures show only weak correlations with ash IN composition and surface area. Our measurements, together with a review of previous volcanic ash IN measurements, suggest that fine-ash particles (equivalent diameters between approximately 1 and 1000 μm) from the majority of volcanoes will exhibit an onset of freezing between ∼250–260 K. In the context of explosive eruptions where super-micron particles are plentiful, this result implies that volcanic clouds are IN-rich relative to meteorological clouds, which typically are IN-limited, and therefore should exhibit distinct microphysics. We can expect that such “overseeded” volcanic clouds will exhibit enhanced ice crystal concentrations and smaller average ice crystal size, relative to dynamically similar meteorological clouds, and that glaciation will tend to occur over a relatively narrow altitude range
A sabre-tooth felid from Coopers Cave (Gauteng, South Africa) and its implications for Megantereon (Felidae: Machairodontinae) taxonomy
Metrical and morphological analysis of a new sabre-tooth felid mandible recovered from the Plio-Pleistocene hominid-bearing site of
Coopers, South Africa, indicates that it can be assigned to the genus Megantereon, though it is by some measures the smallest individual
of this taxon yet described. Comparison of morphological variability within this genus to that found within four extant, medium-sized
felid species (Acinonyx jubatus, Neofelis nebulosa, Panthera pardus and P. uncia) and the extinct genus Smilodon (sister taxon of Megantereon)
provides confirmation of the suggestion by Martínez-Navarro&Palmqvist (1995, 1996) that Megantereon is a geographically polymorphic
genus comprised of at least two species: M. cultridens (Cuvier, 1824) of North America and Europe and M. whitei (Broom, 1937) of Africa
and Europe.Duke University’s
Undergraduate Research Support Office, Howard Hughes Program and Department
of Biological Anthropology and Anatomy; the Palaeo-Anthropology Scientific
Trust (PAST); the National Geographic Society; and the Wenner-Gren
Foundation (grant 6914 to D.J.D.
Loss of KLP-19 polar ejection force causes misorientation and missegregation of holocentric chromosomes
Holocentric chromosomes assemble kinetochores along their length instead of at a focused spot. The elongated expanse of an individual holocentric kinetochore and its potential flexibility heighten the risk of stable attachment to microtubules from both poles of the mitotic spindle (merotelic attachment), and hence aberrant segregation of chromosomes. Little is known about the mechanisms that holocentric species have evolved to avoid this type of error. Our studies of the influence of KLP-19, an essential microtubule motor, on the behavior of holocentric Caenorhabditis elegans chromosomes suggest that it has a major role in combating merotelic attachments. Depletion of KLP-19, which associates with nonkinetochore chromatin, allows aberrant poleward chromosome motion during prometaphase, misalignment of holocentric kinetochores, and multiple anaphase chromosome bridges in all mitotic divisions. Time-lapse movies of GFP-labeled mono- and bipolar spindles demonstrate that KLP-19 generates a force on relatively stiff holocentric chromosomes that pushes them away from poles. We hypothesize that this polar ejection force minimizes merotelic misattachment by maintaining a constant tension on pole–kinetochore connections throughout prometaphase, tension that compels sister kinetochores to face directly toward opposite poles
STEM gender stereotypes from early childhood through adolescence at informal science centers.
Stereotypes about science, technology, engineering and mathematics (STEM) are associated with reduced STEM engagement amongst girls and women. The present study examined these stereotypes from early childhood through adolescence within informal science learning sites (ISLS; science museums, zoos, aquariums). Further, the study explored whether interactions with male or female educators influenced STEM stereotypes. Participants (n = 997, female = 572) were ISLS visitors in the UK and USA who either interacted with an educator, or no educator. With age participants were more likely to report that "both boys and girls" are "usually", "should" be, and "can" be good at STEM. Independent of age, male participants reported that their own gender group "should" be good at STEM. Educator interactions did not influence stereotype responses. These results highlight early childhood as a key developmental window in which to challenge ideas about who can and should be proficient in STEM
Anticoagulant Prescribing for Non-Valvular Atrial Fibrillation in the Veterans Health Administration
Background: Direct acting oral anticoagulants (DOACs) theoretically could contribute to addressing underuse of anticoagulation in non-valvular atrial fibrillation (NVAF). Few studies have examined this prospect, however. The potential of DOACs to address underuse of anticoagulation in NVAF could be magnified within a healthcare system that sharply limits patients\u27 exposure to out-of-pocket copayments, such as the Veterans Health Administration (VA).
Methods and Results: We used a clinical data set of all patients with NVAF treated within VA from 2007 to 2016 (n=987 373). We examined how the proportion of patients receiving any anticoagulation, and which agent was prescribed, changed over time. When first approved for VA use in 2011, DOACs constituted a tiny proportion of all prescriptions for anticoagulants (2%); by 2016, this proportion had increased to 45% of all prescriptions and 67% of new prescriptions. Patient characteristics associated with receiving a DOAC, rather than warfarin, included white race, better kidney function, fewer comorbid conditions overall, and no history of stroke or bleeding. In 2007, before the introduction of DOACs, 56% of VA patients with NVAF were receiving anticoagulation; this dipped to 44% in 2012 just after the introduction of DOACs and had risen back to 51% by 2016.
Conclusions: These results do not suggest that the availability of DOACs has led to an increased proportion of patients with NVAF receiving anticoagulation, even in the context of a healthcare system that sharply limits patients\u27 exposure to out-of-pocket copayments
Selectron Mass Reconstruction and the Resolution of the Linear Collider Detector
We have used ISAJET and the JAS LCD fast simulation to explore the precision of Snowmass Point SPS1a selectron mass reconstruction for the Silicon Detector concept. Simulating collisions at E_cm = 1 TeV, we have found that most of the information constraining the selectron mass is carried in the forward (|cos(theta)| \u3e 0.8) region. We have also found that, for a beam energy spread of 1% (conventional RF design), detector resolution limitations compromise the selectron mass reconstruction only in the forward region. However, for a beam energy spread of less than 0.2% (superconducting RF design), the detector resolution compromises the selectron mass reconstruction over the full angular region
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