Comparison of two models of tethered motion

We consider a random walker whose motion is tethered around a focal point. We use two models that exhibit the same spatial dependence in the steady state but widely different dynamics. In one case, the walker is subject to a deterministic bias towards the focal point, while in the other case, it resets its position to the focal point at random times. The deterministic tendency of the biased walker makes the forays away from the focal point more unlikely when compared to the random nature of the returns of the resetting walker. This difference has consequences on the spatio-temporal dynamics at intermediate times. To show the differences in the two models, we analyze their probability distribution and their dynamics in presence and absence of partially or fully absorbing traps. We derive analytically various quantities: (i) mean first-passage times to one target, where we recover results obtained earlier by a different technique, (ii) splitting probabilities to either of two targets as well as survival probabilities when one or either target is partially absorbing. The interplay between confinement, diffusion and absorbing traps produces interesting non-monotonic effects in various quantities, all potentially accessible in experiments. The formalism developed here may have a diverse range of applications, from study of animals roaming within home ranges and of electronic excitations moving in organic crystals to developing efficient search algorithms for locating targets in a crowded environment.Comment: 26 pages, 7 figure

Crop diversification: Impact on weeds, soybean sudden death syndrome and crop productivity

Crop diversification has diminished in the USA during the past 50 years, and monocultures and short rotation sequences are currently the prevalent cropping systems (Brummer, 1998; Cook, 2006). Simplification of cropping systems has been accompanied by greater reliance on synthetic pesticides and fertilizers to manage weeds, diseases and soil fertility, creating concerns about contamination of underground and surface water by nitrogen, herbicides and soil sediment (Hartwig and Ammon, 2002). Learning how to reduce reliance on synthetic fertilizers and pesticides without compromising farm productivity and profitability is a key priority for Iowa and other parts of the U.S. Corn Belt (Gomez et al., 2012; Cruse et al., 2010). In this report we discuss the impacts of cropping system diversification on weed management, soybean productivity, sudden death syndrome, and root health, based on results from a long-term crop rotation study in Iowa

Energy and Economic Returns by Crop Rotation

Energy and economic returns are presented from 2006-2011 comparing three cropping systems at the ISU Marsden Farm: 2-year conventional corn-soybean rotation and 3- and 4-year rotations that add small grain, red clover and alfalfa

Do non-steroidal anti-inflammatory drugs provide a protective effect on developing Barrett’s esophagus and esophageal cancer? A systematic review and meta-analysis

This is a protocol of a systematic review

EFFICIENT UTILIZATION OF BARE METAL CORES WITH DYNAMIC MONITORING AND CALIBRATION

In existing cloud environments it is not possible to mix, on the same server at the same time, workloads that use part of a processor core, or that use cores on a best-effort basis, with workloads that must both be assigned to a single core and have that core dedicated to their use (i.e., nothing else runs on the core). To address these challenges and inefficiencies, techniques are presented herein that support a division of resources in a way that they can then be appropriately assigned to workloads. One logical pool of cores may be assigned for workloads requiring shared resources and another pool may be assigned for workloads requiring dedicated resources. The boundary between those pools may shift dynamically as, for example, additional resources are required

Is the research you value a waste of money?

Introduction and Hypothesis: Eighty-five percent of health research may be wasted, resulting in $170 billion annually in wasteful research spending worldwide. Given the increased use of randomized trials and their influence on medicine, one method to combat research waste is to conduct RCTs only when a systematic review (SR) suggests more data are needed or when no previous systematic reviews are identified. Here, we hypothesize SRs would be rarely cited as justification for conducting RCTs.Methods: We analysed RCTs published between 2016 and 2018 in New England Journal of Medicine, Lancet, and Journal of the American Medical Association. We performed duplicate and independent data extraction to ensure the accuracy and validity of our data. For each trial, we extracted whether SRs were cited as justification for conducting the clinical trial.Results: Our search retrieved 665 records, of which 628 were included. Overall, 706 SR's were cited in these 628 RCTs; of which, 318 were referenced in the introduction, 82 in the methods, and 306 in the discussion. 49 SRs were cited verbatim as justification for conducting the trial. RCTs published in Lancet were more likely to cite a SR as justification for conducting the trial.Conclusion: Very few clinical trials cite systematic reviews as the basis for undertaking the trial. We believe trialists should be required to present relevant systematic reviews to an ethics or peer review committee demonstrating an unmet need prior to initiating a trial. Eliminating research waste is both a scientific and ethical responsibility

Cross sectional analysis of gender and geographic representation in case study TWD-A

Background: The scientific community should be at the forefront of diversity, equity, and inclusion. However, research suggests that there are wide disparities regarding gender and geography (Lariviere et al. 2013). The National Institutes of Health uses taxpayer money to review and determine who and what projects to fund. We are studying the representation of two subsets of researchers funded by the National Institutes of Health: gender and geography. Therefore, the purpose of this study was to investigate the disparities in gender and geography in the TWD-A case study from the National Institutes of Health.Methods: Our team obtained the rosters for the TWD-A National Institutes of Health study section panels for all meetings held in 2016 and 2021 from the institution’s website. We intended to evaluate data from 2011 but there was no meeting roster available. We extracted the study section members' names, degrees, city, and state of residence; we then used a pilot test to google form for data extraction. Gender was determined through website searches of their respective institutions and if it could not be determined through that mechanism, we used genderize.io to determine gender. A probability value of 0.6 or higher was accepted for gender determination.Results: Initially, female and male representation was nearly equal and eventually became equal by the final year. In 2016 there were 29 total participants in the meetings with 16 (55%) males, and 13 (45%) females. In 2021, there were 28 participants with 14 (50%) males and 14 (50%) females present. We also investigated representation across four regions: West, Midwest, Northeast, and South. In 2016, 16 states were represented; the West and Northeast regions had the highest representation with 8 (30%) participants. The South was less represented with 7 (26%) participants and the Midwest even more so with 4 (15%) participants. Regional participation increased in 2021 with a total of 19 states being represented. We found that the Midwest and West had the most representatives with 7 (27%) participants each while the South and Northeast had 6 (23%) participants each.Conclusions: Our findings suggest that the NIH has improved gender representation within the TWD-A case study. We also found that while geographical representation improved over time, many states remain underrepresented

An Autonomous Agent Framework for Constellation Missions: A Use Case for Predicting Atmospheric CO\u3csub\u3e2\u3c/sub\u3e

Distributed systems missions (DSM), also known as swarm or constellation missions, is an upcoming class of mission design that is changing the current landscape.Swarms enable multipoint observations and higher fidelity science data collection. Autonomy is a critical feature that DSM will require in order to run successfully, especially beyond earth-centric missions and in dynamic environments due to increased delays between ground and space

Contribution of thirdhand smoke to overall tobacco smoke exposure in pediatric patients: study protocol.

BackgroundThirdhand smoke (THS) is the persistent residue resulting from secondhand smoke (SHS) that accumulates in dust, objects, and on surfaces in homes where tobacco has been used, and is reemitted into air. Very little is known about the extent to which THS contributes to children's overall tobacco smoke exposure (OTS) levels, defined as their combined THS and SHS exposure. Even less is known about the effect of OTS and THS on children's health. This project will examine how different home smoking behaviors contribute to THS and OTS and if levels of THS are associated with respiratory illnesses in nonsmoking children.MethodsThis project leverages the experimental design from an ongoing pediatric emergency department-based tobacco cessation trial of caregivers who smoke and their children (NIHR01HD083354). At baseline and follow-up, we will collect urine and handwipe samples from children and samples of dust and air from the homes of smokers who smoke indoors, have smoking bans or who have quit smoking. These samples will be analyzed to examine to what extent THS pollution at home contributes to OTS exposure over and above SHS and to what extent THS continues to persist and contribute to OTS in homes of smokers who have quit or have smoking bans. Targeted and nontargeted chemical analyses of home dust samples will explore which types of THS pollutants are present in homes. Electronic medical record review will examine if THS and OTS levels are associated with child respiratory illness. Additionally, a repository of child and environmental samples will be created.DiscussionThe results of this study will be crucial to help close gaps in our understanding of the types, quantity, and clinical effects of OTS, THS exposure, and THS pollutants in a unique sample of tobacco smoke-exposed ill children and their homes. The potential impact of these findings is substantial, as currently the level of risk in OTS attributable to THS is unknown. This research has the potential to change how we protect children from OTS, by recognizing that SHS and THS exposure needs to be addressed separately and jointly as sources of pollution and exposure.Trial registrationClinicalTrials.gov Identifier: NCT02531594 . Date of registration: August 24, 2015