SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Limit

226

BACKGROUND TO THE DEBATE: Tobacco continues to kill millions of people around the world each year and its use is increasing in some countries, which makes the need for new, creative, and radical efforts to achieve the tobacco control endgame vitally important. One such effort is discussed in this PLOS Medicine Debate, where Simon Chapman presents his proposal for a “smoker’s license” and Jeff Collin argues against. Chapman sets out a case for introducing a smart card license for smokers designed to limit access to tobacco products and encourage cessation. Key elements of the smoker’s license include smokers setting daily limits, financial incentives for permanent license surrender, and a test of health risk knowledge for commencing smokers. Collin argues against the proposal, saying that it would shift focus away from the real vector of the epidemic-the tobacco industry-and that by focusing on individuals it would censure victims, increase stigmatization of smokers, and marginalize the poor.

Concepts: Tobacco, English-language films, Vector space, Proposal, Focusing, Limit, Limit of a sequence, Ryan Reynolds

193

BACKGROUND TO THE DEBATE: Tobacco continues to kill millions of people around the world each year and its use is increasing in some countries, which makes the need for new, creative, and radical efforts to achieve the tobacco control endgame vitally important. One such effort is discussed in this PLOS Medicine Debate, where Simon Chapman presents his proposal for a “smoker’s license” and Jeff Collin argues against. Chapman sets out a case for introducing a smart card license for smokers designed to limit access to tobacco products and encourage cessation. Key elements of the smoker’s license include smokers setting daily limits, financial incentives for permanent license surrender, and a test of health risk knowledge for commencing smokers. Collin argues against the proposal, saying that it would shift focus away from the real vector of the epidemic-the tobacco industry-and that by focusing on individuals it would censure victims, increase stigmatization of smokers, and marginalize the poor.

Concepts: Tobacco, English-language films, Vector space, Proposal, Focusing, Limit, Limit of a sequence, Ryan Reynolds

48

During the Paris Conference in 2015, nations of the world strengthened the United Nations Framework Convention on Climate Change by agreeing to holding “the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C"1. However, "pre-industrial” was not defined. Here we investigate the implications of different choices of the pre-industrial baseline on the likelihood of exceeding these two temperature thresholds. We find that for the strongest mitigation scenario RCP2.6 and a medium scenario RCP4.5 the probability of exceeding the thresholds and timing of exceedance is highly dependent on the pre-industrial baseline, for example the probability of crossing 1.5°C by the end of the century under RCP2.6, varies from 61% to 88% depending on how the baseline is defined. In contrast, in the scenario with no mitigation, RCP8.5, both thresholds will almost certainly be exceeded by the middle of the century with the definition of the pre-industrial baseline of less importance. Allowable carbon emissions for threshold stabilisation are similarly highly dependent on the pre-industrial baseline. For stabilisation at 2°C, allowable emissions decrease by as much as 40% when earlier than 19th century climates are considered as a baseline.

Concepts: Climate, Weather, Definition, Climate change, United Nations, Limit, Global warming, Thresholds

30

The Internet and social media have enabled the mobilization of large crowds to achieve time-critical feats, ranging from mapping crises in real time, to organizing mass rallies, to conducting search-and-rescue operations over large geographies. Despite significant success, selection bias may lead to inflated expectations of the efficacy of social mobilization for these tasks. What are the limits of social mobilization, and how reliable is it in operating at these limits? We build on recent results on the spatiotemporal structure of social and information networks to elucidate the constraints they pose on social mobilization. We use the DARPA Network Challenge as our working scenario, in which social media were used to locate 10 balloons across the United States. We conduct high-resolution simulations for referral-based crowdsourcing and obtain a statistical characterization of the population recruited, geography covered, and time to completion. Our results demonstrate that the outcome is plausible without the presence of mass media but lies at the limit of what time-critical social mobilization can achieve. Success relies critically on highly connected individuals willing to mobilize people in distant locations, overcoming the local trapping of diffusion in highly dense areas. However, even under these highly favorable conditions, the risk of unsuccessful search remains significant. These findings have implications for the design of better incentive schemes for social mobilization. They also call for caution in estimating the reliability of this capability.

Concepts: United States, Geography, Reliability, Media, Limit, Crowd, Mass media, Media bias

28

The paper investigates approaches for loosely coupled GPS/INS integration. Error performance is calculated using a reference trajectory. A performance improvement can be obtained by exploiting additional map information (for example, a road boundary). A constrained solution has been developed and its performance compared with an unconstrained one. The case of GPS outages is also investigated showing how a Kalman filter that operates on the last received GPS position and velocity measurements provides a performance benefit. Results are obtained by means of simulation studies and real data.

Concepts: Estimation theory, Signal processing, Derivative, Solution, Kalman filter, Filtering problem, Limit, Wiener filter

26

Abstract A sensitive and effective method has been developed for the rapid determination of polysorbate-80 content in therapeutic monoclonal antibody (mAb) products. The method is based on the detection of the fluorescence emission of 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid dipotassium salt (bis-ANS) enhanced by the presence of polysorbate-80. The developed method includes two approaches. One requires removal of the mAb from solution prior to analysis, while the other requires only simple sample dilution. The limits of detection and quantitation, calculated from the calibration curve generated in the absence of mAb-A, were 1.5 and 4.7 parts per million, respectively. Given the comparable linear range and linearity of the linear line between the solutions, with or without mAb, the limit of detection and quantitation is assumed to be similar. The dilution method is not only fast and simple in terms of sample preparation, but it is also particularly useful for analyzing the level of polysorbate-80 contained in highly concentrated mAb products. However, given that this method does require availability of polysorbate-80-free materials of mAb for preparation of calibration standards, the protein removal method may be useful for the cases where appropriate protein materials for standard preparation are limited or unavailable.

Concepts: Monoclonal antibodies, Monoclonal antibody therapy, Concentration, Analytical chemistry, Standard, Linear equation, Limited, Limit

22

We evaluated the effects of Bacillus anthracis surrogates, low surface concentrations, surface materials, and assay methods on false-negative rate (FNR) and limit of detection (LOD95 ) for recovering Bacillus spores using a macrofoam-swab sampling procedure.

Concepts: Rates, Assay, Bacillus, Bacillus thuringiensis, Limit, Bacillus anthracis, Bacillaceae, Bacilli

20

Flavour ingredients are an essential part of e-liquids. Their responsible selection and inclusion levels in e-liquids must be guided by toxicological principles. We propose an approach to the screening and toxicological risk assessment of flavour ingredients for e-liquids. The screening involves purity requirements and avoiding ingredients that are carcinogenic, mutagenic or toxic to reproduction. Additionally, owing to the uncertainties involved in potency determination and the derivation of a tolerable level for respiratory sensitisation, we propose excluding respiratory sensitisers. After screening, toxicological data on the ingredients should be reviewed. Inhalation-specific toxicological issues, for which no reliable safe levels can currently be derived, can lead to further ingredient exclusions. We discuss the use of toxicological thresholds of concern for flavours that lack inhalation data suitable for quantitative risk assessment. Higher toxicological thresholds of concern are suggested for flavour ingredients (170 or 980μg/day) than for contaminant assessment (1.5μg/day). Analytical detection limits for measurements of potential reaction and thermal breakdown products in vaping aerosol, should be informed by the contaminant threshold. This principle leads us to recommend 5ng/puff as an appropriate limit of detection for untargeted aerosol measurements.

Concepts: Cancer, Measurement, Toxicology, Detection limit, Uncertainty, Risk assessment, Limit, Thresholds

16

Fisheries management systems around the world are highly diverse in their design, operation, and effectiveness at meeting objectives. A variety of management institutions, strategies, and tactics are used across disparate regions, fishing fleets, and taxonomic groups. At a global level, it is unclear which particular management attributes have greatest influence on the status of fished populations, and also unclear which external factors affect the overall success of fisheries management systems. We used expert surveys to characterize the management systems by species of 28 major fishing nations and examined influences of economic, geographic, and fishery-related factors. A Fisheries Management Index, which integrated research, management, enforcement, and socioeconomic attributes, showed wide variation among countries and was strongly affected by per capita gross domestic product (positively) and capacity-enhancing subsidies (negatively). Among 13 management attributes considered, three were particularly influential in whether stock size and fishing mortality are currently in or trending toward desirable states: extensiveness of stock assessments, strength of fishing pressure limits, and comprehensiveness of enforcement programs. These results support arguments that the key to successful fisheries management is the implementation and enforcement of science-based catch or effort limits, and that monetary investment into fisheries can help achieve management objectives if used to limit fishing pressure rather than enhance fishing capacity. Countries with currently less-effective management systems have the greatest potential for improving long-term stock status outcomes and should be the focus of efforts to improve fisheries management globally.

Concepts: Taxonomy, Affect, Per Capita, Taxonomic rank, Fisheries, Limit, Overfishing, Fishery

8

Blocking PD-1 can re-invigorate exhausted CD8 T cells (TEX) and improve control of chronic infections and cancer. However, whether blocking PD-1 can reprogram TEX into durable memory T cells (TMEM) is unclear. We found that re-invigoration of TEX in mice by PD-L1 blockade caused minimal memory development. After blockade, re-invigorated TEX became re-exhausted if antigen remained high, and failed to become TMEM upon antigen clearance. TEX acquired an epigenetic profile distinct from effector (TEFF) and TMEM cells that was minimally remodeled following PD-L1 blockade. This suggests TEX are a distinct lineage of CD8 T cells. Nevertheless, PD-1 pathway blockade resulted in transcriptional rewiring and re-engagement of effector circuitry in the TEX epigenetic landscape. These data indicate that epigenetic fate inflexibility may limit current immunotherapies.

Concepts: Protein, Gene, Gene expression, T cell, T cells, Major histocompatibility complex, Cytotoxic T cell, Limit