391 research outputs found
To 'Vape' or Smoke? A Discrete Choice Experiment among Adult Smokers
A growing share of the United States population uses e-cigarettes. In response, policymakers are considering regulating e-cigarettes, or have already done so, due to concerns regarding e-cigarettes' public health impact. However, there is currently little population-based evidence to inform these regulatory choices. More information is needed on how policy-relevant factors will likely drive smokers' decision to use e-cigarettes. To provide this information we conduct an online survey and discrete choice experiment to investigate how adult tobacco cigarette smokers' demand for cigarette type varies by four policy-relevant attributes: 1) whether e-cigarettes are considered healthier than tobacco cigarettes, 2) the effectiveness of e-cigarettes as a cessation device, 3) bans on use in public places such as bars and restaurants, and 4) price. Overall, we find that the demand for e-cigarettes is motivated more by smokers' health concerns than by the desire to avoid smoking bans or higher prices. However, results from latent class models reveal three distinct groups of smokers, those who prefer: tobacco cigarettes, e-cigarettes, and using both products. Each group responds differently to the cigarette attributes suggesting that policies will have different impacts across the groups
Long-term no-till and stover retention each decrease the global warming potential of irrigated continuous corn
Over the last 50 years, the most increase in cultivated land area globally has been due to a doubling of irrigated land. Long-term agronomic management impacts on soil organic carbon (SOC) stocks, soil greenhouse gas (GHG) emissions, and global warming potential (GWP) in irrigated systems, however, remain relatively unknown. Here, residue and tillage management effects were quantified by measuring soil nitrous oxide (N2O) and methane (CH4) fluxes and SOC changes (ΔSOC) at a long-term, irrigated continuous corn (Zea mays L.) system in eastern Nebraska, USA. Management treatments began in 2002, and measured treatments included no or high stover removal (0 or 6.8 Mg DM ha-1 yr-1, respectively) under no-till (NT) or conventional disk tillage (CT) with full irrigation (n = 4). Soil N2O and CH4 fluxes were measured for five crop-years (2011 to 2015), and ΔSOC was determined on an equivalent-mass basis to ~30 cm soil depth. Both area- and yield-scaled soil N2O emissions were greater with stover retention compared to removal and for CT compared to NT, with no interaction between stover and tillage practices. Methane comprise
Twelve Years of Stover Removal Increases Soil Erosion Potential without Impacting Yield
Corn (Zea mays L.) stover (non-grain aboveground biomass) in the US Corn Belt is used increasingly for livestock grazing and co-feed and for cellulosic bioenergy production. Continuous stover removal, however, could alter long-term agricultural productivity by affecting soil organic C (SOC) and soil physical properties, indicators of soil fertility and erosion potential. In this study, we showed that 12 consecutive yr of 55% stover removal did not affect mean grain yields at any N fertilizer rate (4.5, 6.3, and 6.0 Mg ha−1 for 60, 120, and 180 kg N ha−1 yr−1, respectively) in a marginally productive, rainfed continuous corn system under no-till (NT). Although SOC increased in the top 30 cm of all soils since 1998 (0.54–0.79 Mg C ha−1 yr−1), stover removal tended to limit SOC gains compared with no removal. Near-surface soils (0–5-cm depth) were more sensitive to stover removal and showed a 41% decrease in particulate organic matter stocks, smaller mean weight diameter of dry soil aggregates, and lower abundance of water-stable soil aggregates compared with soils with no stover removal. Increasing N fertilizer rate mitigated losses in total water-stable aggregates in near-surface soils related to stover removal. Collectively, however, our results indicated soil structure losses in surface soils due to lower C inputs. Despite no effect on crop yields and overall SOC gains with time using NT management, annually removing stover for 12 yr resulted in a higher risk of wind and water erosion at this NT continuous corn site in the western Corn Belt
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Acceptance criteria for heat exchanger head staybolts
Each of the six primary coolant loop systems of the Savannah River Site production reactors contains two parallel single-pass heat exchangers to transfer heat from the primary coolant (D{sub 2}O) to the secondary cooling water (H{sub 2}O). The configuration of the heat exchangers includes a plenary space defined by the heat exchanger tubesheet and the heat exchanger head at both the heat exchanger inlet and outlet to the primary piping. The primary restraint of the heat exchanger head (Type 304 stainless steel) is provided by 84 staybolts (Type 303 stainless steel) which attach to the tubesheet. The staybolts were cap seal-welded in the mid-1960's and are immersed in moderator. Access to inspect the staybolts is limited to a recently-developed ultrasonic technique shooting a beam through the staybolt assembly. Acceptance Criteria to allow disposition of flaws detected by UT inspection have been developed. The structural adequacy to protect against collapse loading of the head is demonstrated by finite element analysis of the head assembly and fracture analysis of flaw postulates in the staybolts. Both normal operation and normal operation plus seismic loading conditions were considered. Several bounding cases containing various configurations of nonactive (exceeding critical flaw size) staybolts were analyzed. The model of the head assembly can be applied to evaluate any active staybolt configurations based on the results from future inspections. 9 refs
Cost-Effectiveness of Peer-Delivered Interventions for Cocaine and Alcohol Abuse among Women: A Randomized Controlled Trial
<div><h3>Aims</h3><p>To determine whether the additional interventions to standard care are cost-effective in addressing cocaine and alcohol abuse at 4 months (4 M) and 12 months (12 M) from baseline.</p> <h3>Method</h3><p>We conducted a cost-effectiveness analysis of a randomized controlled trial with three arms: (1) NIDA's Standard intervention (SI); (2) SI plus a Well Woman Exam (WWE); and, (3) SI, WWE, plus four Educational Sessions (4ES).</p> <h3>Results</h3><p>To obtain an additional cocaine abstainer, WWE compared to SI cost 3,611 at 12 M. Per additional alcohol abstainer, WWE compared to SI cost 7,223 at 4 M and 12 M, respectively. At 12 M, 4ES was dominated (more costly and less effective) by WWE for abstinence outcomes.</p> <h3>Conclusions</h3><p>To our knowledge, this is the first cost-effectiveness analysis simultaneously examining cocaine and alcohol abuse in women. Depending on primary outcomes sought and priorities of policy makers, peer-delivered interventions can be a cost-effective way to address the needs of this growing, underserved population.</p> <h3>Trial Registration</h3><p>ClinicalTrials.gov <a href="http://www.clinicaltrials.gov/ct2/show/NCT01235091">NCT01235091</a></p> </div
Comparing Skill Acquisition Under Varying Onsets of Differential Reinforcement: A Preliminary Analysis
The purpose of the current study was to evaluate the effect of implementing differential reinforcement at different times relative to the onset of teaching new skills to learners with autism spectrum disorder. Specifically, we first determined the most efficient differential reinforcement arrangement for each participant. Using the most efficient arrangement, we evaluated if differential reinforcement from the immediate onset, early onset, or late onset is the most efficient for learners to acquire a new skill. Three children diagnosed with autism spectrum disorder who have a history of receiving intervention based on the principles of applied behavior analysis participated in this study. The immediate onset of differential reinforcement resulted in the most efficient instruction in 6 of 7 comparisons. The results are discussed in light of previous studies and suggestions for future research are provided
Prime movers : mechanochemistry of mitotic kinesins
Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation
Nitrosylation of Myoglobin and Nitrosation of Cysteine by Nitrite in a Model System Simulating Meat Curing
Demand is growing for meat products cured without the addition of sodium nitrite. Instead of the direct addition of nitrite to meat in formulation, nitrite is supplied by bacterial reduction of natural nitrate often added as vegetable juice/powder. However, the rate of nitrite formation in this process is relatively slow, and the total ingoing nitrite is typically less than in conventional curing processes. The objective of this study was to determine the impact of the rate of addition of nitrite and the amount of nitrite added on nitrosylation/nitrosation reactions in a model meat curing system. Myoglobin was preferentially nitrosylated as no decrease in sulfhydryl groups was found until maximum nitrosylmyoglobin color was achieved. The cysteine–myoglobin model retained more sulfhydryl groups than the cysteine-only model (p \u3c 0.05). The rate of nitrite addition did not alter nitrosylation/nitrosation reactions (p \u3e 0.05). These data suggest that the amount of nitrite but not the rate of addition impacts the nitrosylation/nitrosation reactions this syste
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