bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel scheme for Dark Matter Annihilation Feedback in cosmological simulations
Authors: List Florian , Iwanus Nikolas , Elahi Pascal J , Lewis Geraint F 
Published: August 2019

ABSTRACT
We present a new self-consistent method for incorporating Dark Matter Annihilation Feedback (DMAF) in cosmological N-body simulations. The power generated by DMAF is evaluated at each dark matter (DM) particle which allows for flexible energy injection into the surrounding gas based on the specific DM annihilation model under consideration. Adaptive, individual time-steps for gas and DM particles are supported and a new time-step limiter, derived from the propagation of a Sedov–Taylor blast wave, is introduced. We compare this donor-based approach with a receiver-based approach used in recent studies and illustrate the differences by means of a toy example. Furthermore, we consider an isolated halo and a cosmological simulation and show that for these realistic cases, both methods agree well with each other. The extension of our implementation to scenarios such as non-local energy injection, velocity-dependent annihilation cross-sections, and DM decay is straightforward.
Evaluating the evidence of multipolar surface magnetic field in PSR J0108–1431
Authors: Arumugasamy Prakash , Mitra Dipanjan 
Published: August 2019

ABSTRACTPSR J0108–1431 is an old pulsar where the X-ray emission is expected to have a thermal component from the polar cap and a non-thermal component from the magnetosphere. Although the phase-integrated spectra are fit best with a single non-thermal component modelled with a power law (PL) of photon index Γ = 2.9, the X-ray pulse profiles do show the presence of phase-separated thermal and non-thermal components. The spectrum extracted from half the rotational phase away from the X-ray peak fits well with either a single blackbody (BB) or a neutron star atmosphere (NA) model, whereas the spectrum from the rest of the phase range is dominated by a PL. From Bayesian analysis, the estimated BB area is smaller than the expected polar cap area for a dipolar magnetic field with a probability of 86 per cent, whereas the area estimate from the NA model is larger with a probability of 80 per cent. Due to the ambiguity in the thermal emission model, the polar cap area cannot be reliably estimated and hence cannot be used to understand the nature of the surface magnetic field. Instead, we can infer the presence of multipolar magnetic field from the misalignment between the pulsar’s thermal X-ray peak and the radio emission peak. For J0108–1431, we estimated a phase-offset Δϕ > 0.1 between the thermal polar cap emission peak and the radio emission peak and argue that this is best explained by the presence of a multipolar surface magnetic field.
Universe opacity and Type Ia supernova dimming
Authors: Vavryčuk Václav 
Published: August 2019

ABSTRACT
In this paper, I revoke a debate about an origin of Type Ia supernova (SN Ia) dimming. I argue that except for a commonly accepted accelerating expansion of the Universe, a conceivable alternative for explaining this observation is universe opacity caused by light extinction by intergalactic dust, even though it is commonly assumed that this effect is negligible. Using data of the Union2.1 SN Ia compilation, I find that the standard Λ cold dark matter (ΛCDM) model and the opaque universe model fit the SN Ia measurements at redshifts z &lt; 1.4 comparably well. The optimum solution for the opaque universe model is characterized by the B-band intergalactic opacity $\lambda _{B} = 0.10 \pm 0.03 \, \mathrm{Gpc}^{-1}$ and the Hubble constant $H_0 = 68.0 \pm 2.5 \, \mathrm{km\, s^{-1}\, Mpc^{-1}}$. The intergalactic opacity is higher than that obtained from independent observations but still within acceptable limits. This result emphasizes that the issue of the accelerating expansion of the Universe as the origin of the SN Ia dimming is not yet definitely resolved. Obviously, the opaque universe model as an alternative to the ΛCDM model is attractive, because it avoids puzzles and controversies associated with dark energy and the accelerating expansion.
Aegialomys galapagoensis (Rodentia: Cricetidae)
Authors: Prado Joyce R , Percequillo Alexandre R 
Published: August 2019

AbstractAegialomys galapagoensis (Waterhouse, 1839) is a sigmodontine rodent commonly called the Galapagos rice rat. It is a medium-sized rodent, characterized by dense, soft, yellow or copper, weakly grizzled pelage; the dorsum is grayish or brownish and the ventral pelage is pale. It is endemic to the open habitats of the Galapagos Archipelago, occurring on three islands, Santa Fé Island (Barrington Island), San Cristóbal Island (Chatham Island), and Santiago Island (James Island). Restricted populations are considered a major threat to A. galapagoensis conservation throughout most of its range, as well as competition with Rattus rattus. A. galapagoensis is listed as “Vulnerable” by the International Union for Conservation of Nature and Natural Resources, and is listed as “Critically Endangered” on the Ecuador National list.
BioSeq-Analysis2.0: an updated platform for analyzing DNA, RNA and protein sequences at sequence level and residue level based on machine learning approaches
Authors: Liu Bin , Gao Xin , Zhang Hanyu 
Published: August 2019

Abstract
As the first web server to analyze various biological sequences at sequence level based on machine learning approaches, many powerful predictors in the field of computational biology have been developed with the assistance of the BioSeq-Analysis. However, the BioSeq-Analysis can be only applied to the sequence-level analysis tasks, preventing its applications to the residue-level analysis tasks, and an intelligent tool that is able to automatically generate various predictors for biological sequence analysis at both residue level and sequence level is highly desired. In this regard, we decided to publish an important updated server covering a total of 26 features at the residue level and 90 features at the sequence level called BioSeq-Analysis2.0 (http://bliulab.net/BioSeq-Analysis2.0/), by which the users only need to upload the benchmark dataset, and the BioSeq-Analysis2.0 can generate the predictors for both residue-level analysis and sequence-level analysis tasks. Furthermore, the corresponding stand-alone tool was also provided, which can be downloaded from http://bliulab.net/BioSeq-Analysis2.0/download/. To the best of our knowledge, the BioSeq-Analysis2.0 is the first tool for generating predictors for biological sequence analysis tasks at residue level. Specifically, the experimental results indicated that the predictors developed by BioSeq-Analysis2.0 can achieve comparable or even better performance than the existing state-of-the-art predictors.
The Role of Compensation in Nicotine Reduction
Authors: Benowitz Neal L , Donny Eric C , Edwards Kathryn C , Hatsukami Dorothy K , Smith Tracy T 
Published: August 2019

Abstract
The available research on switching from normal nicotine to very low nicotine content cigarettes shows minimal evidence of compensatory smoking. Mathematical estimations suggest that substantial compensation after switching to very low nicotine cigarettes would be impossible. It is likely that smokers who are unable to tolerate the extent of proposed nicotine reduction would switch to other sources of nicotine, rather than try to compensate by smoking more very low nicotine content cigarettes more intensely.
Effects of Cigarette Nicotine Content and Menthol Preference on Perceived Health Risks, Subjective Ratings, and Carbon Monoxide Exposure Among Adolescent Smokers
Authors: Denlinger-Apte Rachel L , Cassidy Rachel N , Colby Suzanne M , Sokolovsky Alexander W , Tidey Jennifer W 
Published: August 2019

Abstract

Introduction
Minimal research exists on adolescent smokers’ perceptions of very low-nicotine-content (VLNC) cigarettes. As approximately half of adolescent smokers prefer menthol cigarettes, it is important to consider the influence of menthol preference on VLNC cigarette perceptions and to what extent menthol preference may affect VLNC smoking behavior. This study examined the effects of cigarette nicotine content and menthol preference or menthol smoking on health risk perceptions, subjective ratings, and carbon monoxide (CO) boost in adolescent smokers.

Methods
Across two counterbalanced sessions, adolescent smokers sampled VLNC and normal nicotine content (NNC) research cigarettes following overnight abstinence. Cigarettes were mentholated or non-mentholated consistent with participants’ usual brand. In each session, participants smoked the research cigarette and then completed the Perceived Health Risk Scale and Cigarette Evaluation Scale. Breath CO readings were obtained pre- and post-smoking. Mixed-factor ANOVA tests compared outcomes with cigarette type (VLNC vs. NNC) as the within-subjects factor and menthol preference as the between-subjects factor.

Results
Participants (N = 50) were M = 17.7 years old, smoked M = 8.2 cigarettes/day, and 56% typically smoked menthol cigarettes. Participants reported lower risk of developing lung cancer, other cancers, emphysema, bronchitis, and heart disease (ps ≤ .05) when smoking VLNC cigarettes relative to NNC cigarettes. Perceived risk of addiction and stroke did not differ by nicotine content. Menthol preference or menthol smoking did not moderate risk perceptions, subjective ratings, or CO boost.

Conclusions
Adolescents may incorrectly perceive that VLNC cigarettes are less harmful products. Health communication campaigns could help to correct VLNC misperceptions and potentially minimize unintended consequences of a nicotine reduction policy.
Biochemical Verification of Tobacco Use and Abstinence: 2019 Update
Authors: Benowitz Neal L , Bernert John T , Foulds Jonathan , Hecht Stephen S , Jacob Peyton , Jarvis Martin J , Joseph Anne , Oncken Cheryl , Piper Megan E 
Published: August 2019

AbstractBackgroundThe changing prevalence and patterns of tobacco use, the advent of novel nicotine delivery devices, and the development of new biomarkers prompted an update of the 2002 Society for Research on Nicotine and Tobacco (SRNT) report on whether and how to apply biomarker verification for tobacco use and abstinence.MethodsThe SRNT Treatment Research Network convened a group of investigators with expertise in tobacco biomarkers to update the recommendations of the 2002 SNRT Biochemical Verification Report.ResultsBiochemical verification of tobacco use and abstinence increases scientific rigor and is recommended in clinical trials of smoking cessation, when feasible. Sources, appropriate biospecimens, cutpoints, time of detection windows and analytic methods for carbon monoxide, cotinine (including over the counter tests), total nicotine equivalents, minor tobacco alkaloids, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol are reviewed, as well as biochemical approaches to distinguishing cigarette smoking from use of electronic nicotine delivery devices (ENDS).ConclusionsRecommendations are provided for whether and how to use biochemical verification of tobacco use and abstinence. Guidelines are provided on which biomarkers to use, which biospecimens to use, optimal cutpoints, time windows to detection, and methodology for biochemical verifications. Use of combinations of biomarkers is recommended for assessment of ENDS use.ImplicationsBiochemical verification increases scientific rigor, but there are drawbacks that need to be assessed to determine whether the benefits of biochemical verification outweigh the costs, including the cost of the assays, the feasibility of sample collection, the ability to draw clear conclusions based on the duration of abstinence, and the variability of the assay within the study population. This paper provides updated recommendations from the 2002 SRNT report on whether and how to use biochemical markers in determining tobacco use and abstinence.
Research on Behavioral Discrimination of Nicotine May Inform FDA Policy on Setting a Maximum Nicotine Content in Cigarettes
Authors: Perkins Kenneth A 
Published: August 2019

Abstract

Introduction
The Food and Drug Administration may set a maximum nicotine content in cigarettes to minimize smoking’s addictiveness. Our recent research may indirectly support setting levels applicable to the population of dependent smokers below 1 mg/g (mg nicotine/g of tobacco filler).

Methods
Using a within-subjects design in laboratory-based studies totaling 61 nontreatment seeking adult dependent smokers, Spectrum research cigarettes with nicotine contents ranging from 1.3 to 17 mg/g (just one per session) were compared with the lowest content available, 0.4 mg/g. Identified for each participant was the smallest difference in nicotine content, or “threshold,” between cigarettes that still supported behavioral discrimination (ie, ability to objectively distinguish their difference). The next lower nicotine content cigarette, not discriminated (by definition), was labeled their “subthreshold.” Subjective perceptions and choice behavior were also assessed.

Results
Thresholds varied widely among all 61 smokers but, importantly, fewer than 7% of smokers could discriminate the two lowest, 1.3 versus 0.4 mg/g nicotine, meaning more than 90% could not do so. Moreover, we found a consistent association between their nicotine discrimination threshold and their subjective perceptions and subsequent reinforcement behavior later in the session. Specifically, a participant’s discrimination threshold cigarette was also more highly rated and preferred (ie, self-administered), whereas their subthreshold cigarette was rated similarly to the 0.4 mg/g and not preferred.

Conclusions
Cigarette nicotine content below the threshold for perceiving nicotine’s effects (ie, its discriminability) in nearly all smokers from a no nicotine comparison is likely below 1.0 mg/g, or less than or equal to 10% of that in typical commercial cigarettes.

Implications
Cigarettes with nicotine contents able to be discriminated (threshold) are also reinforcing, and those unable to be discriminated are not reinforcing, as anticipated. Yet, research explicitly comparing cigarettes with contents below 1.0 mg/g versus no nicotine (ie, a “placebo”) is needed with larger samples. Results may confirm what nicotine content lower than 1.0 mg/g is below the threshold for discrimination (and self-administration) in the vast majority (&gt;95%) of adult dependent smokers as well as teens beginning to smoke. Identifying that content would strongly support the Food and Drug Administration policy to establish a maximum nicotine content in cigarettes that will not maintain dependence.
Potential Moderating Effects of Psychiatric Diagnosis and Symptom Severity on Subjective and Behavioral Responses to Reduced Nicotine Content Cigarettes
Authors: Gaalema Diann E , Tidey Jennifer W , Davis Danielle R , Sigmon Stacey C , Heil Sarah H , Stitzer Maxine L , Desarno Michael J , Diaz Valeria , Hughes John R , Higgins Stephen T 
Published: August 2019

Abstract

Introduction
Given FDA’s authority to implement a cigarette nicotine reduction policy, possible outcomes of this regulation must be examined, especially among those who may be most affected, such as those with comorbid psychiatric disorders.

Methods
In this secondary analysis of a multisite, randomized, clinical laboratory study, we used analyses of variance to examine the effects of nicotine dose (0.4, 2.4, 5.2, and 15.8 mg/g of tobacco), depressive and anxiety diagnoses (depression only, anxiety only, both, or neither), and depressive and anxiety symptom severity on cigarette choice, smoke exposure, craving, and withdrawal across three vulnerable populations: socioeconomically disadvantaged women of reproductive age, opioid-dependent individuals, and those with affective disorders (n = 169).

Results
Diagnosis and symptom severity largely had no effects on smoking choice, total puff volume, or CO boost. Significant main effects on craving and withdrawal were observed, with higher scores in those with both anxiety and depression diagnoses compared with depression alone or no diagnosis, and in those with more severe depressive symptoms (p’s &lt; .001). These factors did not interact with nicotine dose. Cigarettes with &lt;15.8 mg/g nicotine were less reinforcing, decreased total puff volume, and produced significant but lower magnitude and shorter duration reductions in craving and withdrawal than higher doses (p’s &lt; .01).

Conclusions
Reducing nicotine dose reduced measures of cigarette addiction potential, with little evidence of moderation by either psychiatric diagnosis or symptom severity, providing evidence that those with comorbid psychiatric disorders would respond to a nicotine reduction policy similarly to other smokers.

Implications
Thus far, controlled studies in healthy populations of smokers have demonstrated that use of very low nicotine content cigarettes reduces cigarette use and dependence without resulting in compensatory smoking. These analyses extend those findings to a vulnerable population of interest, those with comorbid psychiatric disorders. Cigarettes with very low nicotine content were less reinforcing, decreased total puff volume, and produced significant but lower magnitude and shorter duration reductions in craving and withdrawal than higher doses. These nicotine dose effects did not interact with psychiatric diagnosis or mood symptom severity suggesting that smokers in this vulnerable population would respond to a nicotine reduction strategy similarly to other smokers.
Effects of Framing Nicotine Reduction in Cigarettes on Anticipated Tobacco Product Use Intentions and Risk Perceptions Among US Adult Smokers
Authors: Popova Lucy , Owusu Daniel , Nyman Amy L , Weaver Scott R , Yang Bo , Huang Jidong , Ashley David L 
Published: August 2019

Abstract

Introduction
In 2017, the US Food and Drug Administration (FDA) proposed lowering the amount of nicotine in combusted cigarettes to minimally addictive levels. If used, to encourage cessation and maximize the benefits of this action, the FDA needs to determine the most effective way to communicate to the public the practical impact of this nicotine tobacco product standard.

Methods
Data were collected in 2018 from a nationally representative, online probability sample of 1198 adult smokers (aged ≥18 years old) in the United States. Smokers were randomly assigned one of five versions of the question regarding what they would most likely do if nicotine in cigarettes was reduced (nicotine levels were reduced by 95%; the government reduced nicotine levels by 95%; cigarettes were no longer addictive; cigarettes no longer relieved cravings; cigarettes were changed so that you would be able to quit more easily). Effects of framing on anticipated tobacco use intentions and perceived risk of very low nicotine cigarettes (VLNCs) were evaluated with multinomial logistic regressions.

Results
Framing the nicotine tobacco product standard as cigarettes no longer relieved cravings resulted in the highest proportion of smokers reporting they intend to quit in response to this standard (43.9%), lowest proportions reporting anticipated intentions to continue using combusted tobacco products (45.3%), and lowest proportion believing that VLNCs are less harmful than regular cigarettes (26%).

Conclusions
Different frames of nicotine reduction in cigarettes differentially affected smokers’ anticipated tobacco use intentions and perceived risk of VLNCs. Presenting reduction as making cigarettes unable to relieve cravings might be particularly effective at motivating cessation.
Exposure to a Tobacco-Specific Carcinogen Among Adolescent Smokeless Tobacco Users in Rural California, United States
Authors: Chaffee Benjamin W , Jacob Peyton , Couch Elizabeth T , Benowitz Neal L 
Published: August 2019

Abstract

Introduction
Approximately the same percentage of male high school students in the United States currently uses conventional smokeless tobacco as smokes cigarettes, resulting in toxin exposure.

Methods
This study assessed tobacco product use (smokeless, combustible, and electronic cigarettes) and nicotine and carcinogen exposures in a sample of 594 male rural high school baseball players—a population traditionally at risk for smokeless tobacco use. Salivary specimens were assayed for cotinine (a biomarker of nicotine exposure) and urine specimens for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL, a biomarker of the carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) using liquid chromatography–tandem mass spectrometry.

Results
The prevalence of past 30-day use of any tobacco product was 29%. Past 7-day smokeless tobacco use (prevalence: 13%) was associated with the highest levels of cotinine and NNAL observed in the sample, whether smokeless tobacco was used exclusively (geometric means: cotinine 11.1 ng/mL; NNAL 31.9 pg/mg-creatinine) or in combination with combustible products (geometric means: cotinine 31.6 ng/mL; NNAL 50.0 pg/mg creatinine). Cotinine and NNAL levels were incrementally higher in each increasing category of smokeless tobacco use frequency. However, observed levels were lower than previously reported for adults, likely reflecting less smokeless use per day among adolescents.

Conclusions
Based on these biomarker observations, adolescents who use conventional smokeless tobacco products are exposed to substantial levels of nicotine and NNK. Although exposed to lower levels than adult smokeless users, the findings are concerning given the young age of the sample and tendency for smokeless tobacco users to increase use intensity over time.

Implications
This study demonstrates that adolescents using smokeless tobacco are exposed to levels of nicotine and NNK that increase with use frequency and that exceed exposures among peers using other tobacco products. Youth smokeless tobacco use in the United States has not declined along with youth smoking prevalence, giving greater importance to this health concern. To reduce youth (and adult) exposures, needed actions include effective smokeless tobacco use prevention, potentially in combination with reducing the levels of harmful and potentially harmful chemicals in smokeless tobacco products currently popular among adolescents.