bluuebunny/crossref_metadata_2025 huggingface dataset:
A Review on Joint Optimization of Maintenance with Production Planning and Spare Part Inventory Management
Authors: Hwang J Q , Samat H A
Published: July 2019

In maintenance system, the increasing complexity of the manufacturing system and the joint optimization of maintenance is catching the attention of researches. Therefore, the aim of the paper is to review the literatures on joint optimization of maintenance with other interrelated functions in the manufacturing system. The classification is made based on the type of decision variables, which are production planning (production scheduling, lot sizing and buffer) and spare part inventory management. The relationships and dependencies are explain in the discussion to show the significance of the integrated model. Most studies considered two functions in their integrated model, which is either maintenance policy with production planning or maintenance policy with spare part management. It can be observe that research on optimization of more than two functions is still new and yet to be explore. Moreover, most researches focused at the decision-making phase without extensive discussion in various functions that might involve. The objective function which is the cost is also presented in the paper. The objective function is categorized into two criteria: maintenance related cost and also inventory and spare part related cost.
Development of the Ergonomic Wrist Posture Range for Indonesian in Typing Activity Using Electromyograph
Authors: Soewardi H , Zhafira N
Published: July 2019

Carpal Tunnel Syndrome (CTS) is one of the most common neuropathies which occurs due to repetitive activity of hand using non-neutral wrist posture whether in flexion, extension, or ulnar and radial. Even though this posture may be inevitable, however it should be confined in maximum range. Thus, this is very significant to develop the allowable of maximum deviation of wrist. Objective of this study is to determine the maximum range of wrist postures in such four motions with evaluating the muscle contraction at wrist. A case study applied is to type a manuscript using computer. Experimental study was conducted by using electromyograph to identify Maximum Voluntary Contraction (MVC) on Flexor Digitorum Superficialis (FDS) and Abductor Pollicis Brevis (APB). Ten healthy university students (5 females, 5 males) were participated with age between 20 to 23 years old. The statistical analysis was conducted to test the hypothesis. Result of this study shows that the suggested maximum wrist posture range is not greater than 30˚ extension, 20˚ flexion, 20˚ ulnar, and 20˚ radial, although the neutral posture of 0˚ was highly suggested. This guideline is proven to be valid for both male and female.
Template-free synthesis of Ta3N5 hollow nanospheres as a visible-light-driven photocatalyst
Authors: Wang Taifeng , Arakaki Atsushi , Kisailus David
Published: July 2019

Ultrathin mesoporous Ta3N5 hollow nanospheres were synthesized via a facile and orchestrated template-free solution-based synthesis followed by thermal nitridation. A systematic investigation of structural evolution with annealing revealed a progressive crystallization with concurrent development of mesoporosity and modification of chemical composition with nitridation time. Subsequent performance of as-prepared photocatalysts were evaluated by the degradation of methylene blue under visible light irradiation (λ > 400 nm). Ta3N5 hollow nanospheres exhibited higher photocatalytic activity than Ta3N5 nanorods or bulk Ta3N5, which can be attributed to their engineered structure as well as the oxygen and nitrogen content.
Associations Between Alcohol Policies and Adolescent Alcohol Use: A Pooled Analysis of GSHS and ESPAD Data
Authors: Noel Jonathan K
Published: July 2019

Aims

Alcohol-attributable harm remains high worldwide, and alcohol use among adolescents is particularly concerning. The purpose of this study is to determine the effect of national alcohol control policies on adolescent alcohol use in low-, middle- and high-income countries and improve on previous cross-national attempts to estimate the impact of alcohol policy on this population.

Methods

Data on adolescent (n = 277,110) alcohol consumption from 84 countries were pooled from the Global School-based Health Survey and the European School Survey Project on Alcohol and Other Drugs. Alcohol use measures included lifetime alcohol use, current (past 30 days) alcohol use and current (past 30 days) binge drinking. Information on national alcohol control policies was obtained from the World Health Organization’s Global Information System on Alcohol and Health and scored for effectiveness. Main effects were estimated using two-level, random intercept hierarchical linear models, and the models were adjusted for sex and age of the participants, and pattern of drinking score, gross domestic product based on purchasing power parity and study at the country level.

Results

Availability (OR [95% CI] = 0.991 [0.983, 0.999]), marketing (OR [95% CI] = 0.994 [0.988, 1.000]) and pricing (OR [95% CI] = 0.955 [0.918, 0.993]) policies were inversely associated with lifetime drinking status. Pricing policies were also inversely associated with current binge drinking status among current drinkers (OR [95% CI] = 0.939 [0.894, 0.986]). There were no associations between the included alcohol policies and current drinking status.

Conclusions

Strong availability, marketing and pricing policies can significantly and practically impact adolescent alcohol consumption.
Evolution of increased vigour associated with allopolyploidization in the newly formed invasive species Salsola ryanii
Authors: Welles Shana R , Ellstrand Norman C
Published: July 2019

A correlation between allopolyploidization and increased fitness is an explanation for the importance of allopolyploidy throughout evolution, specifically plant evolution. Although many authors have suggested correlation between allopolyploidy and increased fitness, common garden comparisons testing hypotheses about fitness shifts associated with allopolyploidy are lacking. In this study, we test the theory that allopolyploidy is associated with increased fitness in the newly formed allopolyploid weed Salsola ryanii. We conducted a common garden comparison over 2 years to determine how different fitness correlates (plant volume, plant mass and estimated seed number) of the newly formed allopolyploid species S. ryanii compares to its progenitors (S. tragus and S. australis) at a site within the range of all the newly formed allopolyploid and both of its progenitors. We document an increase in above-ground plant mass and above-ground volume in the newly formed allopolyploid compared to its progenitors. Plant mass and volume of the newly formed allopolyploid relative to its progenitors was dependent on year. The results of this study support the hypothesis that allopolyploidization is associated with increased growth, which is consistent with predictions that allopolyploid lineages experience vigour due to fixed heterozygosity.
Winter corticosterone and body condition predict breeding investment in a nonmigratory bird
Authors: Montreuil-Spencer Chloé , Schoenemann Kelsey , Lendvai Ádám Z , Bonier Frances
Published: July 2019

Reproduction is an energetically demanding life history stage that requires costly physiological and behavioral changes, yet some individuals will invest more into reproduction and breed more successfully than others. To understand variation in reproductive investment, previous studies have evaluated factors during breeding, but conditions outside of this life history stage may also play a role. Using a free-ranging population of black-capped chickadees (Poecile atricapillus), we assessed the repeatability of plastic traits relating to energetic condition (circulating initial corticosterone concentrations and body condition) during the nonbreeding season and evaluated whether these traits predicted reproductive investment in the subsequent breeding season. We found that initial corticosterone concentrations and an index of body condition, but not fat score, were moderately repeatable over a 1-week period in winter. This trait repeatability supports the interpretation that among-individual variation in these phenotypic traits could reflect an intrinsic strategy to cope with challenging conditions across life history stages. We found that females with larger fat reserves during winter laid eggs sooner and tended to spend more time incubating their eggs and feeding their offspring. In contrast, we found that females with higher residual body mass delayed breeding, after controlling for the relationship between fat score and timing of breeding. Additionally, females with higher initial corticosterone in winter laid lighter eggs. Our findings suggest that conditions experienced outside of the breeding season may be important factors explaining variation in reproductive investment.
Snapchat’s Dialectics of Socialization: Revisiting the Theory of the Spectacle for a Critical Political Economy of Social Media
Authors: Briziarelli Marco
Published: July 2019

In this paper, I use the online app Snapchat as a prism through which I illustrate a “spectacular” power of current informational/communicative capitalism: the ability to subsume and integrate a broad range of practices into a holistic socialization process that operates both at the level of media platform structures and at the level of subjectivization mechanisms. I advance this argument by historicizing Guy Debord’s notion of the Spectacle via Autonomist Marxism and Voloshinov’s materialist semiotics. Shedding light on the tensions inhabiting the post-Fordist labor process its users are involved in—such as autonomy/heteronomy, sociability/alienation, and display/concealment—I show how Snapchat points to a Spectacle that consistently operates through a dialectic of socialization, which enables and compels, consorts and estranges, and deceives and exhibits.
The Clinical Picture and Severity of Invasive Meningococcal Disease Serogroup W Compared With Other Serogroups in the Netherlands, 2015–2018
Authors: Loenenbach Anna D , van der Ende Arie , de Melker Hester E , Sanders Elisabeth A M , Knol Mirjam J
Published: July 2019

Background

An increase in invasive meningococcal disease (IMD) serogroup W (IMD-W) cases caused by sequence type-11 clonal complex (cc11) was observed from October 2015 in the Netherlands. We compared the clinical picture and disease outcome of IMD-W cases with other serogroups, adjusting for host characteristics.

Methods

We included IMD cases reported from January 2015 to June 2018 in the Netherlands and assessed clinical manifestation and symptoms at disease onset and calculated case fatality rates (CFRs). We used logistic regression to compare clinical manifestations and mortality of IMD-W with IMD caused by meningococci serogroup B, Y, or C, adjusting for age, gender, and comorbidities.

Results

A total of 565 IMD cases were reported, of which 204 were IMD-W, 270 IMD-B, 63 IMD-Y, and 26 IMD-C. Most IMD-W isolates belonged to cc11 (93%; 175/188). Compared with other serogroups, IMD-W patients were diagnosed more often with septicemia (46%) or pneumonia (12%) and less often with meningitis (17%, P < .001). IMD-W cases presented more often with respiratory symptoms (45%, P < .001); 16% of IMD-W patients presented with diarrhea without IMD-specific symptoms (P = .061). The CFR for IMD-W was 16% (32/199, P < .001). The differences between IMD-W and other serogroups remained after adjusting for age, gender, and comorbidities.

Conclusions

The atypical presentation and severe outcome among IMD-W cases could not be explained by age, gender, and comorbidities. Almost all our IMD-W cases were caused by cc11. More research is needed to identify the bacterial factors involved in clinical presentation and severity of IMD-W cc11.
Labour market deregulation, taxation and labour productivity in a Marxian–Kaldorian perspective: the case of Italy
Authors: Forges Davanzati Guglielmo , Giangrande Nicolò
Published: July 2019

This paper deals with the Italian recession in a theoretical framework which combines Marxian and Kaldorian elements. The interpretation proposed of the slow rate of growth of the Italian economy in the last decades is based on the view that the implementation of a liberal agenda (mainly in the form of increasing labour market deregulation and increasing taxation on labour) has generated increasing income inequality and the reduction of the growth rate. The basic idea, derived from Kaldor, is that the decline of labour share, the increasing precariousness and measures of fiscal consolidation have reduced domestic demand with negative effects on the level of employment and the growth of labour productivity. Moreover, the increase in public debt involves increasing taxation (mainly on labour), which, in turn, contributes to the reduction of the rate of growth of labour productivity via the deterioration of the quality of the workforce.
Reinterventions after freestyle stentless aortic valve replacement: an assessment of procedural risks
Authors: Schneider Adriaan W , Hazekamp Mark G , Versteegh Michel I M , de Weger Arend , Holman Eduard R , Klautz Robert J M , Bruggemans Eline F , Braun Jerry
Published: July 2019

OBJECTIVES

Repeat aortic valve interventions after previous stentless aortic valve replacement (AVR) are considered technically challenging with an increased perioperative risk, especially after full-root replacement. We analysed our experience with reinterventions after stentless AVR.

METHODS

A total of 75 patients with previous AVR using a Freestyle stentless bioprosthesis (31 subcoronary, 15 root-inclusion and 29 full-root replacement) underwent reintervention in our centre from 1993 until December 2018. Periprocedural data were retrospectively collected from the department database and follow-up data were prospectively collected.

RESULTS

Median age was 62 years (interquartile range 47–72 years). Indications for reintervention were structural valve deterioration (SVD) in 47, non-SVD in 13 and endocarditis in 15 patients. Urgent surgery was required in 24 (32%) patients. Reinterventions were surgical AVR in 16 (21%), root replacement in 51 (68%) and transcatheter AVR in 8 (11%) patients. Early mortality was 9.3% (n = 7), but decreased to zero in the past decade in 28 patients undergoing elective reoperation. Per indication, early mortality was 9% for SVD, 8% for non-SVD and 13% for endocarditis. Aortic root replacement had the lowest early mortality rate (6%), followed by surgical AVR (13%) and transcatheter AVR (25%, 2 patients with coronary artery obstruction). Pacemaker implantation rate was 7%. Overall survival rate at 10 years was 69% (95% confidence interval 53–81%).

CONCLUSIONS

Repeat aortic valve interventions after stentless AVR carry an increased, but acceptable, early mortality risk. Transcatheter valve-in-valve procedures after stentless AVR require careful consideration of prosthesis leaflet position to prevent obstruction of the coronary arteries.
Academic salaries and public evaluation of university research: Evidence from the UK Research Excellence Framework
Authors: De Fraja Gianni , Facchini Giovanni , Gathergood John
Published: July 2019

We study the effects of public evaluation of university research on the pay structures of academic departments. A simple equilibrium model of university pay determination shows how the pay–performance relationship can be explained by the incentives inherent in the research evaluation process. We then analyse the pay–performance relationship using data on the salary of all UK university full professors, matched to the performance of their departments from the 2014 UK government evaluation of research, the Research Excellence Framework (REF). A cross sectional empirical analysis shows that both average pay level and pay inequality in a department are positively related to performance. It also shows that the pay–performance relationship is driven by a feature of the research evaluation that allows academics to transfer the affiliation of published research across universities. To assess the effect of the REF on pay structure, we take advantage of the time dimension of our data and of inherent uncertainty in the evaluation of the performance of academic departments generated by the rules of the exercise. Our results indicate that higher achieving departments benefit from increased subsequent hiring and higher professorial salaries with the salary benefits of REF performance concentrated among the highest paid professors.
Atrial high-rate episodes: prevalence, stroke risk, implications for management, and clinical gaps in evidence
Authors: Bertaglia Emanuele , Blank Benjamin , Blomström-Lundqvist Carina , Brandes Axel , Cabanelas Nuno , Dan G -Andrei , Dichtl Wolfgang , Goette Andreas , de Groot Joris R , Lubinski Andrzej , Marijon Eloi , Merkely Béla , Mont Lluis , Piorkowski Christopher , Sarkozy Andrea , Sulke Neil , Vardas Panos , Velchev Vasil , Wichterle Dan , Kirchhof Paulus
Published: July 2019

Self-terminating atrial arrhythmias are commonly detected on continuous rhythm monitoring, e.g. by pacemakers or defibrillators. It is unclear whether the presence of these arrhythmias has therapeutic consequences. We sought to summarize evidence on the prevalence of atrial high-rate episodes (AHREs) and their impact on risk of stroke. We performed a comprehensive, tabulated review of published literature on the prevalence of AHRE. In patients with AHRE, but without atrial fibrillation (AF), we reviewed the stroke risk and the potential risk/benefit of oral anticoagulation. Atrial high-rate episodes are found in 10–30% of AF-free patients. Presence of AHRE slightly increases stroke risk (0.8% to 1%/year) compared with patients without AHRE. Atrial high-rate episode of longer duration (e.g. those >24 h) could be associated with a higher stroke risk. Oral anticoagulation has the potential to reduce stroke risk in patients with AHRE but is associated with a rate of major bleeding of 2%/year. Oral anticoagulation is not effective in patients with heart failure or survivors of a stroke without AF. It remains unclear whether anticoagulation is effective and safe in patients with AHRE. Atrial high-rate episodes are common and confer a slight increase in stroke risk. There is true equipoise on the best way to reduce stroke risk in patients with AHRE. Two ongoing trials (NOAH-AFNET 6 and ARTESiA) will provide much-needed information on the effectiveness and safety of oral anticoagulation using non-vitamin K antagonist oral anticoagulants in patients with AHRE.
Effect of ancient grains and grain-free carbohydrate sources on extrusion parameters and nutrient utilization by dogs
Authors: Pezzali Julia Guazzelli , Aldrich Charles Gregory
Published: July 2019

The aim of this study was to evaluate the impact of ancient grain and grain-free carbohydrate sources on extrusion process, nutrient utilization, and palatability by dogs. Two maintenance dog diets were formulated with same proportions of carbohydrates: 1) ancient grain diet (AG) with spelt, millet, and sorghum; and 2) grain-free diet (GF) which had potato, peas, and tapioca starch. Experimental diets were extruded over 5 replicates in a completely randomized experimental design. Digestibility was carried out with 12 dogs in a switch-back experimental design. The GF diet required 22.6 and 25.9% more (P < 0.05) specific mechanical energy and in-barrel moisture input, respectively, than AG to produce kibbles out of the extruder with similar bulk density (P > 0.05). After drying, GF kibbles were less dense and more expanded, but harder than AG kibbles (P < 0.05). Dogs preferred GF over AG in the palatability assessment of uncoated kibbles. Apparent nutrient digestibility of dry matter, organic matter, gross energy, crude protein, and crude fat were not affected by treatment (P > 0.05). However, total dietary fiber (TDF) digestibility was 31.9% greater for dogs fed GF (P < 0.05). Moreover, wet fecal output was higher, and fecal dry matter was lower for dogs under GF (P < 0.05). The results demonstrated that GF and AG diets behaved differently during extrusion, but were similarly utilized by dogs, with exception of TDF. Thus, fiber content of grain-free diets should be monitored to maximize fecal quality.
Bupenorphine in Wisconsin Drivers: Concerns for Impairment?
Authors: Edwards Lorrine D
Published: July 2019

Opinions vary on whether buprenorphine can cause impairment in drivers. Relatively little information on the observed effects of buprenorphine, outside a laboratory or a controlled driving course, exist in the literature. The Wisconsin State Laboratory of Hygiene monitored the detection of buprenorphine and its pharmacologically active metabolite, norbuprenorphine (NBUP), in Wisconsin drivers over a 2-year period. A total of 204 individuals (78 females and 126 males) were driving under the influence of buprenorphine and/or NBUP. Concentrations in whole blood (ng/mL) ranged (mean) from 0.6 to 14 (2.0) and 0.5 to 20 (2.1) for buprenorphine and NBUP, respectively. Poly-substance use is extremely prevalent in Wisconsin operating while intoxicated casework, so prevalent that only four of the previously described cases had buprenorphine and/or NBUP as the only drug(s) detected. This paper summarizes and highlights the case histories and observed impairments of those four cases. Law enforcement (LE) made contact with three of the four subjects due to either a crash or poor/reckless driving. Police reports and observations made by LE, including drug recognition expert (DRE) evaluations, were collected. Physical and behavioral observations made by LE varied and included a combination of narcotic analgesic, central nervous system depressant- and stimulant-like effects. Impaired balance and lack of coordination during the administration of the Standardized Field Sobriety Tests were documented by the arresting officers and/or the DRE. While the number of buprenorphine-only cases reported here is limited, the results demonstrate the complex paradigm associated with forensic interpretation of buprenorphine in driving under the influence of drugs casework and the frequency of poly-substance administration in Wisconsin drivers.
Measuring Aging and Identifying Aging Phenotypes in Cancer Survivors
Authors: Guida Jennifer L , Ahles Tim A , Belsky Daniel , Campisi Judith , Cohen Harvey Jay , DeGregori James , Fuldner Rebecca , Ferrucci Luigi , Gallicchio Lisa , Gavrilov Leonid , Gavrilova Natalia , Green Paige A , Jhappan Chamelli , Kohanski Ronald , Krull Kevin , Mandelblatt Jeanne , Ness Kirsten K , O’Mara Ann , Price Nathan , Schrack Jennifer , Studenski Stephanie , Theou Olga , Tracy Russell P , Hurria Arti
Published: July 2019

Observational data have shown that some cancer survivors develop chronic conditions like frailty, sarcopenia, cardiac dysfunction, and mild cognitive impairment earlier and/or at a greater burden than similarly aged individuals never diagnosed with cancer or exposed to systemic or targeted cancer therapies. In aggregate, cancer- and treatment-related physical, cognitive, and psychosocial late- and long-term morbidities experienced by cancer survivors are hypothesized to represent accelerated or accentuated aging trajectories. However, conceptual, measurement, and methodological challenges have constrained efforts to identify, predict, and mitigate aging-related consequences of cancer and cancer treatment. In July 2018, the National Cancer Institute convened basic, clinical, and translational science experts for a think tank titled “Measuring Aging and Identifying Aging Phenotypes in Cancer Survivors.” Through the resulting deliberations, several research and resource needs were identified, including longitudinal studies to examine aging trajectories that include detailed data from before, during, and after cancer treatment; mechanistic studies to elucidate the pathways that lead to the emergence of aging phenotypes in cancer survivors; long-term clinical surveillance to monitor survivors for late-emerging effects; and tools to integrate multiple data sources to inform understanding of how cancer and its therapies contribute to the aging process. Addressing these needs will help expand the evidence base and inform strategies to optimize healthy aging of cancer survivors.
Review on global change status and its impacts on the Tibetan Plateau environment
Authors: Latif Aamir , Ilyas Sana , Zhang Yangjian , Xin Yuqin , Zhou Lin , Zhou Quan
Published: July 2019

The Tibetan Plateau (TP) holds fundamental ecological and environmental significances to China and Asia. The TP also lies in the core zone of the belt and road initiative. To protect the TP environment, a comprehensive screening on current ecological research status is entailed. The teased out research gap can also be utilized as guidelines for the recently launched major research programs, i.e. the second TP scientific expedition and silk and belt road research plan. The findings showed that the TP has experienced significant temperature increase at a rate of 0.2°C per decade since 1960s. The most robust warming trend was found in the northern plateau. Precipitation also exhibited an increasing trend but with high spatial heterogeneity. Changing climates have caused a series of environmental consequences, including lake area changes, glacier shrinkage, permafrost degradation and exacerbated desertification. The rising temperature is the main reason behind the glaciers shrinkage, snow melting, permafrost degradation and lake area changes on the TP and neighboring regions. The projected loss of glacial area on the plateau is estimated to be around 43% by 2070 and 75% by the end of the century. Vegetation was responsive to the changed environments, varied climates and intensified human activities by changing phenology and productivity. Future global change study should be more oriented toward integrating various research methods and tools, and synthesizing diverse subjects of water, vegetation, atmosphere and soil.
The global South as a solution to cope with the crisis: Following the transnational itineraries of the precarised Spaniards towards Algeria
Authors: Cabezón-Fernández María-Jesús , Sempere-Souvannavong Juan-David
Published: July 2019

The rising economies in the global South have been a destination of expatriates, businessmen, and high-skilled migrants during the bonanza times. A move to these places was seen as cosmopolitan way to improve professional careers by acquiring international experience or higher quality of education. However, in the post-crisis context after the crash of 2008, the needs of the Southern European populace have changed due to the precarisation of their social contexts in terms of economic insecurity which instead have been pushed them to seek job opportunities across borders to avoid unemployment. In this article, we shed light on the transnational strategies performed by the precarised Spaniards moving to Algeria to cope with the constraints that the crisis initiated in their day-to-day needs. In doing so, under the lens of the transnational theory and the mobility turn, we performed multi-sited fieldwork between 2012 and 2016, based on in-depth interviews with participant observation of Spaniards who have developed a transnational strategy between both countries since 2005 to 2016. The goal of this longitudinal methodology was to identify how the effects of the crisis have encouraged the evolution of these transnational itineraries attending to the particular tensions when moving to this country culturally different in the other side of the Mediterranean. Through three specific cases, we show how these Spaniards reshaped their trajectories from short-term mobilities, punctual and voluntarily planned and scheduled, to circular mobilities, perceived as an imposition by the social context without the possibility to decide when to come back home.
Biofluorescent Worlds – II. Biological fluorescence induced by stellar UV flares, a new temporal biosignature
Authors: O'Malley-James Jack T , Kaltenegger Lisa
Published: July 2019

Our first targets in the search for signs of life are orbiting nearby M stars, such as the planets in the Proxima Centauri, Ross-128, LHS-1140, and TRAPPIST-1 systems. Future ground-based discoveries, and those from the TESS mission, will provide additional close-by targets. However, young M stars tend to be very active, flaring frequently and causing UV fluxes on the surfaces of HZ planets to become biologically harmful. Common UV-protection methods used by life (e.g. living underground, or underwater) would make a biosphere harder to detect. However, photoprotective biofluorescence, ‘up-shifting’ UV to longer, safer wavelengths, could increase a biosphere's detectability. Here we model intermittent emission at specific wavelengths in the visible spectrum caused by biofluorescence as a new temporal biosignature for planets around active M stars. We use the absorption and emission characteristics of common coral fluorescent pigments and proteins to create model spectra and colours for an Earth-like planet in such a system, accounting for different surface features, atmospheric absorption, and cloud cover. We find that for a cloud-free planet biofluorescence could induce a temporary change in brightness that is significantly higher than the reflected flux alone, causing up to two orders-of-magnitude change in planet–star contrast, compared to a non-fluorescent state, if the surface is fully covered by a highly efficient fluorescent biosphere. Hence, UV-flare induced biofluorescence presents previously unexplored possibilities for a new temporal biosignature that could be detectable by instruments like those planned for the extremely large telescope and could reveal hidden biospheres.
Mass transport in galaxy discs limits black hole growth to sub-Eddington rates
Authors: Eastwood Daniel S , Khochfar Sadegh , Trew Arthur
Published: July 2019

Supermassive black holes (SMBHs) observed to have masses of $M_\bullet \sim 10^9 \, \mathrm{M_\odot }$ at z ≳ 6, <1 Gyr after the big bang, are thought to have been seeded by massive black holes that formed before growing concurrently with the formation of their host galaxies. We model analytically the idealized growth of seed black holes, fed through gas inflow from growing proto-galaxy discs. The inflow depends on the disc gravitational stability and thus varies with black hole and disc mass. We find that for a typical host halo, the efficiency of angular momentum transport, as parametrized by the disc viscosity, is the limiting factor in determining the inflow rate and the black hole accretion rate. For our fiducial case, we find an upper black hole mass estimate of $M_\bullet \sim 1.8 \times 10^7 \, \mathrm{M_{\odot }}$ at z = 6. Only in the extreme case of ∼1016 M⊙ haloes at z = 6 produces SMBH masses of ∼109 M⊙. However, the number density of such haloes is many orders of magnitude below the estimated 1 Gpc−3 of SMBHs at z = 6, indicating that viscosity driven accretion is too inefficient to feed the growth of seeds into $M_\bullet \sim 10^9 \, \mathrm{M_\odot }$ SMBHs by z ∼ 6. We demonstrate that major mergers are capable of resolving the apparent discrepancy in black hole mass at z = 6, with some dependence on the exact choice of orbital parameters of the merger.
Massive neutrinos leave fingerprints on cosmic voids
Authors: Kreisch Christina D , Pisani Alice , Carbone Carmelita , Liu Jia , Hawken Adam J , Massara Elena , Spergel David N , Wandelt Benjamin D
Published: July 2019

Do void statistics contain information beyond the tracer 2-point correlation function? Yes! As we vary the sum of the neutrino masses, we find void statistics contain information absent when using just tracer 2-point statistics. Massive neutrinos uniquely affect cosmic voids. We explore their impact on void clustering using both the DEMNUni and MassiveNuS simulations. For voids, neutrino effects depend on the observed void tracers. As the neutrino mass increases, the number of small voids traced by cold dark matter particles increases and the number of large voids decreases. Surprisingly, when massive, highly biased, haloes are used as tracers, we find the opposite effect. The scale at which voids cluster, as well as the void correlation, is similarly sensitive to the sum of neutrino masses and the tracers. This scale-dependent trend is not due to simulation volume or halo density. The interplay of these signatures in the void abundance and clustering leaves a distinct fingerprint that could be detected with observations and potentially help break degeneracies between different cosmological parameters. This paper paves the way to exploit cosmic voids in future surveys to constrain the mass of neutrinos.
Fast likelihood-free cosmology with neural density estimators and active learning
Authors: Alsing Justin , Charnock Tom , Feeney Stephen , Wandelt Benjamin
Published: July 2019

Likelihood-free inference provides a framework for performing rigorous Bayesian inference using only forward simulations, properly accounting for all physical and observational effects that can be successfully included in the simulations. The key challenge for likelihood-free applications in cosmology, where simulation is typically expensive, is developing methods that can achieve high-fidelity posterior inference with as few simulations as possible. Density-estimation likelihood-free inference (DELFI) methods turn inference into a density estimation task on a set of simulated data-parameter pairs, and give orders of magnitude improvements over traditional Approximate Bayesian Computation approaches to likelihood-free inference. In this paper we use neural density estimators (NDEs) to learn the likelihood function from a set of simulated datasets, with active learning to adaptively acquire simulations in the most relevant regions of parameter space on-the-fly. We demonstrate the approach on a number of cosmological case studies, showing that for typical problems high-fidelity posterior inference can be achieved with just $\mathcal {O}(10^3)$ simulations or fewer. In addition to enabling efficient simulation-based inference, for simple problems where the form of the likelihood is known, DELFI offers a fast alternative to MCMC sampling, giving orders of magnitude speed-up in some cases. Finally, we introduce pydelfi – a flexible public implementation of DELFI with NDEs and active learning – available at https://github.com/justinalsing/pydelfi.
Maximally rotating supermassive stars at the onset of collapse: effects of gas pressure
Authors: Dennison Kenneth A , Baumgarte Thomas W , Shapiro Stuart L
Published: July 2019

The ‘direct collapse’ scenario has emerged as a promising evolutionary track for the formation of supermassive black holes early in the Universe. In an idealized version of such a scenario, a uniformly rotating supermassive star spinning at the mass-shedding (Keplerian) limit collapses gravitationally after it reaches a critical configuration. Under the assumption that the gas is dominated by radiation pressure, this critical configuration is characterized by unique values of the dimensionless parameters J/M2 and Rp/M, where J is the angular momentum, Rp the polar radius, and M the mass. Motivated by a previous perturbative treatment, we adopt a fully non-linear approach to evaluate the effects of gas pressure on these dimensionless parameters for a large range of masses. We find that gas pressure has a significant effect on the critical configuration even for stellar masses as large as $M \simeq 10^6 \, \mathrm{M}_{\odot }$. We also calibrate two approximate treatments of the gas pressure perturbation in a comparison with the exact treatment, and find that one commonly used approximation in particular results in increasing deviations from the exact treatment as the mass decreases, and the effects of gas pressure increase. The other approximation, however, proves to be quite robust for all masses $M \gtrsim 10^4 \, \mathrm{M}_{\odot }$.
Crust cooling of the neutron star in Aql X-1: different depth and magnitude of shallow heating during similar accretion outbursts
Authors: Degenaar N , Ootes L S , Page D , Wijnands R , Parikh A S , Homan J , Cackett E M , Miller J M , Altamirano D , Linares M
Published: July 2019

The structure and composition of the crust of neutron stars plays an important role in their thermal and magnetic evolution, hence in setting their observational properties. One way to study the properties of the crust of a neutron star, is to measure how it cools after it has been heated during an accretion outburst in a low-mass X-ray binary (LMXB). Such studies have shown that there is a tantalizing source of heat, of currently unknown origin, that is located in the outer layers of the crust and has a strength that varies between different sources and different outbursts. With the aim of understanding the mechanism behind this ‘shallow heating’, we present Chandra and Swift observations of the neutron star LMXB Aql X-1, obtained after its bright 2016 outburst. We find that the neutron star temperature was initially much lower, and started to decrease at much later time, than observed after the 2013 outburst of the source, despite the fact that the properties of the two outbursts were very similar. Comparing our data to thermal evolution simulations, we infer that the depth and magnitude of shallow heating must have been much larger during the 2016 outburst than during the 2013 one. This implies that basic neutron star parameters that remain unchanged between outbursts do not play a strong role in shallow heating. Furthermore, it suggests that outbursts with a similar accretion morphology can give rise to very different shallow heating. We also discuss alternative explanations for the observed difference in quiescent evolution after the 2016 outburst.
Kelvin–Helmholtz instability in self-gravitating streams
Authors: Aung Han , Mandelker Nir , Nagai Daisuke , Dekel Avishai , Birnboim Yuval
Published: July 2019

Self-gravitating gaseous filaments exist on many astrophysical scales, from sub-pc filaments in the interstellar medium to Mpc scale streams feeding galaxies from the cosmic web. These filaments are often subject to Kelvin–Helmholtz Instability (KHI) due to shearing against a confining background medium. We study the non-linear evolution of KHI in pressure-confined self-gravitating gas streams initially in hydrostatic equilibrium, using analytic models and hydrodynamic simulations, not including radiative cooling. We derive a critical line mass, or mass per unit length, as a function of the stream Mach number and density contrast with respect to the background, μcr(Mb, δc) ≤ 1, where μ = 1 is normalized to the maximal line mass for which initial hydrostatic equilibrium is possible. For μ < μcr, KHI dominates the stream evolution. A turbulent shear layer expands into the background and leads to stream deceleration at a similar rate to the non-gravitating case. However, with gravity, penetration of the shear layer into the stream is halted at roughly half the initial stream radius by stabilizing buoyancy forces, significantly delaying total stream disruption. Streams with μcr < μ ≤ 1 fragment and form round, long-lived clumps by gravitational instability (GI), with typical separations roughly eight times the stream radius, similar to the case without KHI. When KHI is still somewhat effective, these clumps are below the spherical Jeans mass and are partially confined by external pressure, but they approach the Jeans mass as μ → 1 and GI dominates. We discuss potential applications of our results to streams feeding galaxies at high redshift, filaments in the ISM, and streams resulting from tidal disruption of stars near the centres of massive galaxies.
Low-frequency radio study of MACS clusters at 610 and 235 MHz using the GMRT
Authors: Paul Surajit , Salunkhe Sameer , Datta Abhirup , Intema Huib T
Published: July 2019

Studies have shown that mergers of massive galaxy clusters produce shocks and turbulence in the intracluster medium, these events possibly creating radio relics, as well as radio haloes. Here we present Giant Metrewave Radio Telescope (GMRT) dual-band (235- and 610-MHz) radio observations of four such clusters from the MAssive Cluster Survey (MACS) catalogue. We report the discovery of a very faint, diffuse, elongated radio source with a projected size of about 0.5 Mpc in cluster MACSJ0152.5−2852. We also confirm the presence of a radio-relic-like source (about 0.4 Mpc, previously reported at 325 MHz) in cluster MACSJ0025.4−1222. Proposed relics in both these clusters are found apparently inside the virial radius, instead of at their usual peripheral location, while no radio haloes are detected. These high-redshift clusters (z = 0.584 and 0.413) are among the earliest merging systems detected from cluster radio emission. In cluster MACSJ1931.8-2635, we found a radio mini-halo and an interesting highly bent pair of radio jets. Also, we present here a maiden study of low-frequency (GMRT 235- and 610-MHz) spectral and morphological signatures of the previously known radio cluster MACSJ0014.3−3022 (Abell 2744). This cluster hosts a relatively flat spectrum ($\alpha ^{610}_{235}\sim -1.15$), giant (∼1.6 Mpc each) halo–relic structure and a nearby high-speed ($1769\pm ^{148}_{359}$ km s−1) merger shock ($\mathcal {M}=2.02\pm ^{0.17}_{0.41}$) originating from a possible second merger in the cluster.
A multiwavelength study of the debris disc around 49 Cet
Authors: Pawellek Nicole , Moór Attila , Milli Julien , Kóspál Ágnes , Olofsson Johan , Ábrahám Péter , Keppler Miriam , Kral Quentin , Pohl Adriana , Augereau Jean-Charles , Boccaletti Anthony , Chauvin Gaël , Choquet Élodie , Engler Natalia , Henning Thomas , Langlois Maud , Lee Eve J , Ménard François , Thébault Philippe , Zurlo Alice
Published: July 2019

In a multiwavelength study of thermal emission and scattered light images we analyse the dust properties and structure of the debris disc around the A1-type main-sequence star 49 Cet. As a basis for this study, we present new scattered light images of the debris disc known to possess a high amount of both dust and gas. The outer region of the disc is revealed in former coronagraphic H-band and our new Y-band images from the Very Large Telescope SPHERE instrument. We use the knowledge of the disc’s radial extent inferred from ALMA observations and the grain size distribution found by spectral energy distribution fitting to generate semidynamical dust models of the disc. We compare the models to scattered light and thermal emission data and find that a disc with a maximum surface density at 110 au and shallow edges can describe both the thermal emission and the scattered light observations. This suggests that grains close to the blow-out limit and large grains stem from the same planetesimal population and are mainly influenced by radiation pressure. The influence of inward transport processes could not be analysed in this study.
CTCF cooperates with CtIP to drive homologous recombination repair of double-strand breaks
Authors: Hwang Soon Young , Kang Mi Ae , Baik Chul Joon , Lee Yejin , Hang Ngo Thanh , Kim Byung-Gyu , Han Joo Seok , Jeong Jae-Hoon , Park Daechan , Myung Kyungjae , Lee Jong-Soo
Published: July 2019

The pleiotropic CCCTC-binding factor (CTCF) plays a role in homologous recombination (HR) repair of DNA double-strand breaks (DSBs). However, the precise mechanistic role of CTCF in HR remains largely unclear. Here, we show that CTCF engages in DNA end resection, which is the initial, crucial step in HR, through its interactions with MRE11 and CtIP. Depletion of CTCF profoundly impairs HR and attenuates CtIP recruitment at DSBs. CTCF physically interacts with MRE11 and CtIP and promotes CtIP recruitment to sites of DNA damage. Subsequently, CTCF facilitates DNA end resection to allow HR, in conjunction with MRE11–CtIP. Notably, the zinc finger domain of CTCF binds to both MRE11 and CtIP and enables proficient CtIP recruitment, DNA end resection and HR. The N-terminus of CTCF is able to bind to only MRE11 and its C-terminus is incapable of binding to MRE11 and CtIP, thereby resulting in compromised CtIP recruitment, DSB resection and HR. Overall, this suggests an important function of CTCF in DNA end resection through the recruitment of CtIP at DSBs. Collectively, our findings identify a critical role of CTCF at the first control point in selecting the HR repair pathway.
A hidden human proteome encoded by ‘non-coding’ genes
Authors: Lu Shaohua , Zhang Jing , Lian Xinlei , Sun Li , Meng Kun , Chen Yang , Sun Zhenghua , Yin Xingfeng , Li Yaxing , Zhao Jing , Wang Tong , Zhang Gong , He Qing-Yu
Published: July 2019

It has been a long debate whether the 98% ‘non-coding’ fraction of human genome can encode functional proteins besides short peptides. With full-length translating mRNA sequencing and ribosome profiling, we found that up to 3330 long non-coding RNAs (lncRNAs) were bound to ribosomes with active translation elongation. With shotgun proteomics, 308 lncRNA-encoded new proteins were detected. A total of 207 unique peptides of these new proteins were verified by multiple reaction monitoring (MRM) and/or parallel reaction monitoring (PRM); and 10 new proteins were verified by immunoblotting. We found that these new proteins deviated from the canonical proteins with various physical and chemical properties, and emerged mostly in primates during evolution. We further deduced the protein functions by the assays of translation efficiency, RNA folding and intracellular localizations. As the new protein UBAP1-AST6 is localized in the nucleoli and is preferentially expressed by lung cancer cell lines, we biologically verified that it has a function associated with cell proliferation. In sum, we experimentally evidenced a hidden human functional proteome encoded by purported lncRNAs, suggesting a resource for annotating new human proteins.
Influenza and vaccination: beliefs and practices of local authority staff
Authors: Mc Conalogue D , Verle N , Ellis H , Scott S
Published: July 2019

Background

Influenza causes large outbreaks every year. Professionals outside healthcare, including social care staff and non-care giving roles, have a key role in protecting their clients and sustaining operational productivity through influenza vaccination. There has been little research on non-healthcare staff working with vulnerable people and those working in non-caregiving settings regarding influenza and influenza vaccination.

Aims

To understand the practices, experiences, perceptions and motivations of local authority staff regarding influenza and influenza vaccination.

Methods

Semi-structured focus groups were carried out with local authority staff in Gloucestershire. Transcripts were thematically analysed.

Results

Participants tended to perceive influenza as a serious illness, where a person had a specific risk factor or during pandemics. They did not feel vulnerable unless they had previous experience of infection or had an underlying health condition. Motivation to vaccinate was based on previous experience of influenza, where they had a close family member at risk or when working directly with vulnerable clients. Beliefs about negative side effects of the vaccine were the strongest reason for vaccine refusal. Ease of access to vaccination through on-site clinics is key to uptake. Management are perceived as key motivators or blockers to vaccine uptake.

Conclusions

Workers outside healthcare settings do not feel vulnerable to influenza and have low motivation to vaccinate, unless they have previous experience of infection or an underlying health condition. Vaccination programmes must proactively address workers’ beliefs and motivations to ensure their participation in flu vaccination programmes.