bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical impact of an anti-biofilm Hydrofiber dressing in hard-to-heal wounds previously managed with traditional antimicrobial products and systemic antibiotics
Authors: Metcalf Daniel G , Bowler Philip G
Published: January 2020

Background

Hard-to-heal wounds are often compromised by the presence of biofilm. This presents an infection risk, yet traditional antimicrobial wound care products and systemic antibiotics are often used despite the uncertainty of therapeutic success and wound progression. The aim of this study was to investigate the clinical impact of a next-generation anti-biofilm Hydrofiber wound dressing (AQUACEL Ag+ Extra[AQAg+ E]) in hard-to-heal wounds that had previously been treated unsuccessfully with traditional silver-, iodine- or polyhexamethylene biguanide (PHMB)-containing dressings and products and/or systemic antibiotics.

Methods

Clinical case study evaluations of the anti-biofilm dressing were conducted, where deteriorating or stagnant wounds were selected by clinicians and primary dressings were replaced by the anti-biofilm dressing for up to 4 weeks, or as deemed clinically appropriate, with monitoring via case report forms. The data was stratified for cases where traditional silver-, iodine- or PHMB-containing products, or systemic antibiotics, had been used prior to the introduction of the anti-biofilm dressing.

Results

Sixty-five cases were identified for inclusion, wounds ranging in duration from 1 week to 20 years (median: 12 months). In 47 (72%) cases the wounds were stagnant, while 15 (23%) were deteriorating; 3 wounds were not recorded. After an average of 4.2 weeks of management with the anti-biofilm dressing (range: 1–11 weeks), in 11 (17%) cases the wounds had healed (i.e. complete wound closure), 40 (62%) wounds improved, 9 (14%) wounds remained the same and 5 (8%) wounds deteriorated.

Conclusions

The introduction of this anti-biofilm dressing into protocols of care that had previously involved wound management with traditional antimicrobial products and/or antibiotics was shown to facilitate improvements in the healing status of most of these hard-to-heal wounds. Dressings containing proven anti-biofilm technology, in combination with antimicrobial silver and exudate management technology, appear to be an effective alternative to traditional antimicrobial products and antibiotics in the cases presented here. The use of antimicrobial wound dressings that contain anti-biofilm technology may have a key role to play in more effective wound management and antibiotic stewardship.
Impact of Diabetes and Low Body Mass Index on Tuberculosis Treatment Outcomes
Authors: Kornfeld Hardy , Sahukar Shruthi B , Procter-Gray Elizabeth , Kumar Nathella P , West Kim , Kane Kevin , Natarajan Mohan , Li Wenjun , Babu Subash , Viswanathan Vijay
Published: January 2020

Background

Diabetes was identified as a tuberculosis (TB) risk factor mostly in retrospective studies with limited assessments of metabolic variables. The prospective Effects of Diabetes on Tuberculosis Severity study compared adults with pulmonary TB in Chennai, India, who were classified as having either diabetes or a normal glucose tolerance at enrollment.

Methods

Baseline TB severity, sputum conversion, and treatment outcomes (cure, failure, death, or loss to follow-up) were compared between groups with respect to glycemic status and body mass index (BMI).

Results

The cohort of 389 participants included 256 with diabetes and 133 with a normal glucose tolerance. Low BMIs (<18.5 kg/m2) were present in 99 (74.4%) of nondiabetic participants and 85 (33.2%) of those with diabetes. Among participants with normal or high BMIs, rates of cure, treatment failure, or death did not vary by glycemic status. Participants with low BMIs had the highest radiographic severity of disease, the longest time to sputum culture conversion, and the highest rates of treatment failure and death. Among participants with low BMIs, poorly controlled diabetes (glycohemoglobin [HbA1c] ≥8.0%) was unexpectedly associated with better TB treatment outcomes. A high visceral adiposity index was associated with adverse outcomes and, despite an overall correlation with HbA1c, was elevated in some low-BMI individuals with normal glucose tolerance.

Conclusions

In this South Indian cohort, a low BMI was significantly associated with an increased risk for adverse TB treatment outcomes, while comorbid, poorly controlled diabetes lessened that risk. A high visceral adiposity index, either with or without dysglycemia, might reflect a novel TB susceptibility mechanism linked to adipose tissue dysfunction.
The sources of heterogeneity in firm performance: lessons from Italy1
Authors: Landini Fabio , Arrighetti Alessandro , Bartoloni Eleonora
Published: January 2020

An extensive body of literature documents large and persistent within-industry heterogeneity of firm performance. While some authors explain such evidence in terms of input misallocation, we provide an alternative analytical framework that integrates insights from resource-based and institutional approaches. We interpret firms’ behaviour as the result of the interaction among exogenous and endogenous factors. Exogenous factors, both supply and demand related, define the opportunity set that is available to firms. Endogenous factors reflect instead firm-specific interpretations of such set, which, combined with the available resources and capabilities, determine a firm’s strategic responses, which can be markedly heterogeneous. Whenever the diversity of firm conducts is associated with relatively small profit differentials, firm heterogeneity can persist. Evidence based on the evolution of labour productivity and profit dispersion in the Italian manufacturing sector between the 1990s and early 2000s provides support for our interpretative framework.
HSPMdb: a computational repository of heat shock protein modulators
Authors: Singh Prashant , Unik Breezy , Puri Anuradhika , Nagpal Gandharva , Singh Balvinder , Gautam Ankur , Sharma Deepak
Published: January 2020

Heat shock proteins (Hsp) are among highly conserved proteins across all domains of life. Though originally discovered as a cellular response to stress, these proteins are also involved in a wide range of cellular functions such as protein refolding, protein trafficking and cellular signalling. A large number of potential Hsp modulators are under clinical trials against various human diseases. As the number of modulators targeting Hsps is growing, there is a need to develop a comprehensive knowledge repository of these findings which is largely scattered. We have thus developed a web-accessible database, HSPMdb, which is a first of its kind manually curated repository of experimentally validated Hsp modulators (activators and inhibitors). The data was collected from 176 research articles and current version of HSPMdb holds 10 223 entries of compounds that are known to modulate activities of five major Hsps (Hsp100, Hsp90, Hsp70, Hsp60 and Hsp40) originated from 15 different organisms (i.e. human, yeast, bacteria, virus, mouse, rat, bovine, porcine, canine, chicken, Trypanosoma brucei and Plasmodium falciparum). HSPMdb provides comprehensive information on biological activities as well as the chemical properties of Hsp modulators. The biological activities of modulators are presented as enzymatic activity and cellular activity. Under the enzymatic activity field, parameters such as IC50, EC50, DC50, Ki and KD have been provided. In the cellular activity field, complete information on cellular activities (percentage cell growth inhibition, EC50 and GI50), type of cell viability assays and cell line used has been provided. One of the important features of HSPMdb is that it allows users to screen whether or not their compound of interest has any similarity with the previously known Hsp modulators. We anticipate that HSPMdb would become a valuable resource for the broader scientific community working in the area of chaperone biology and protein misfolding diseases. HSPMdb is freely accessible at http://bioinfo.imtech.res.in/bvs/hspmdb/index.php
Understanding the challenges of non-food industrial product contamination
Authors: Cunningham-Oakes Edward , Weiser Rebecca , Pointon Tom , Mahenthiralingam Eshwar
Published: January 2020

Preventing microbial contamination of non-food products is a major area of industrial microbiology where preservatives are used to stop microbial growth. However, microorganisms occasionally overcome product preservation, causing recalls and the implementation of multiple procedures to prevent further contamination. Correct reporting of microbial contamination in non-food industrial products is vital, especially if spoilage organisms are antimicrobial resistant and pose a health threat. Gram-negative bacteria such as Pseudomonas, Burkholderia and Enterobacteriaceae are frequently reported as non-food product contaminants, including species that overlap current antimicrobial resistance priorities. Historical analysis of recall databases highlighted that for greater than 15% of contamination incidents, the causative microbial agents are reported as unidentified. Here we review the current antimicrobial resistant bacterial species associated with non-food product contamination and evaluate recall reporting in Europe from 2005 to 2018. Our review shows that 49% of microbial contaminants are reported as unidentified despite frequent detection of antimicrobial resistant pathogens; in contrast, 98% of food-related microbial contaminants are classified. Recommendations to fill this microbial identification gap in non-food product recalls are made. Overall, reporting standards for microbial contamination in non-food products must be improved to enable surveillance and for understanding the risks associated with antimicrobial resistant microorganisms
Independent Transposon Exaptation Is a Widespread Mechanism of Redundant Enhancer Evolution in the Mammalian Genome
Authors: Barth Nicolai K H , Li Lifei , Taher Leila
Published: January 2020

Many regulatory networks appear to involve partially redundant enhancers. Traditionally, such enhancers have been hypothesized to originate mainly by sequence duplication. An alternative model postulates that they arise independently, through convergent evolution. This mechanism appears to be counterintuitive to natural selection: Redundant sequences are expected to either diverge and acquire new functions or accumulate mutations and become nonfunctional. Nevertheless, we show that at least 31% of the redundant enhancer pairs in the human genome (and 17% in the mouse genome) indeed originated in this manner. Specifically, for virtually all transposon-derived redundant enhancer pairs, both enhancer partners have evolved independently, from the exaptation of two different transposons. In addition to conferring robustness to the system, redundant enhancers could provide an evolutionary advantage by fine-tuning gene expression. Consistent with this hypothesis, we observed that the target genes of redundant enhancers exhibit higher expression levels and tissue specificity as compared with other genes. Finally, we found that although enhancer redundancy appears to be an intrinsic property of certain mammalian regulatory networks, the corresponding enhancers are largely species-specific. In other words, the redundancy in these networks is most likely a result of convergent evolution.
Spousal Influences on Monthly Disability in Late-Life Marriage in the Precipitating Events Project
Authors: Monin Joan K , Laws Holly , Gahbauer Evelyne , Murphy Terrence E , Gill Thomas M
Published: January 2020

Objectives

Few studies have examined spousal influences on disability in late-life marriage, and no prior study has examined these associations using monthly data. Drawing from interdependence theory, we hypothesized that one spouse currently having higher disability would be positively associated with their partner having higher disability in the next month. We also examined whether participants were at risk for increased disability when both spouses had higher prior disability. In addition, we examined gender differences in spousal associations.

Method

Data were from 37 married couples in the Precipitating Events Project, an ongoing longitudinal study of 754 initially nondisabled adults aged 70 years and older. Assessments included monthly disability (13 basic, instrumental, and mobility activities of daily living) and demographics.

Results

As hypothesized, higher disability in one spouse was positively associated with higher subsequent disability in their partner. Also, wives with higher disability were especially vulnerable to subsequent increased disability when husbands had higher disability.

Discussion

Incorporating a spouse’s current disability level in modeling older adults’ subsequent disability provides additional predictive information. Wives with greater disability may be at a particularly high risk of accelerated decline when their husbands have greater disability.
On the importance of benchmarking algorithms under realistic noise conditions
Authors: Birnie Claire , Chambers Kit , Angus Doug , Stork Anna L
Published: January 2020

Testing with synthetic data sets is a vital stage in an algorithm’s development for benchmarking the algorithm’s performance. A common addition to synthetic data sets is White, Gaussian Noise (WGN) which is used to mimic noise that would be present in recorded data sets. The first section of this paper focuses on comparing the effects of WGN and realistic modelled noise on standard microseismic event detection and imaging algorithms using synthetic data sets with recorded noise as a benchmark. The data sets with WGN underperform on the trace-by-trace algorithm while overperforming on algorithms utilizing the full array. Throughout, the data sets with realistic modelled noise perform near identically to the recorded noise data sets. The study concludes by testing an algorithm that simultaneously solves for the source location and moment tensor of a microseismic event. Not only does the algorithm fail to perform at the signal-to-noise ratios indicated by the WGN results but the results with realistic modelled noise highlight pitfalls of the algorithm not previously identified. The misleading results from the WGN data sets highlight the need to test algorithms under realistic noise conditions to gain an understanding of the conditions under which an algorithm can perform and to minimize the risk of misinterpretation of the results.
The static and time-dependent signature of ocean–continent and ocean–ocean subduction: the case studies of Sumatra and Mariana complexes
Authors: Marotta A M , Restelli F , Bollino A , Regorda A , Sabadini R
Published: January 2020

The anomalous density structure at subduction zones, both in the wedge and in the upper mantle, is analysed to shed light on the processes that are responsible for the characteristic gravity fingerprints of two types of subduction: ocean–continent and ocean–ocean. Our modelling is then performed within the frame of the EIGEN-6C4 gravitational disturbance pattern of two subductions representative of the above two types, the Sumatra and Mariana complexes, finally enabling the different characteristics of the two patterns to be observed and understood on a physical basis, including some small-scale details. A 2-D viscous modelling perpendicular to the trench accounts for the effects on the gravity pattern caused by a wide range of parameters in terms of convergence velocity, subduction dip angle and lateral variability of the crustal thickness of the overriding plate, as well as compositional differentiation, phase changes and hydration of the mantle. Plate coupling, modelled within a new scheme where the relative velocity at the plate contact results self-consistently from the thermomechanical evolution of the system, is shown to have an important impact on the gravity signature. Beyond the already understood general bipolar fingerprint of subduction, perpendicular to the trench, we obtain the density and gravity signatures of the processes occurring within the wedge and mantle that are responsible for the two different gravity patterns. To be compliant with the geodetic EIGEN-6C4 gravitational disturbance and to compare our predictions with the gravity at Sumatra and Mariana, we define a model normal Earth. Although the peak-to-peak gravitational disturbance is comparable for the two types of subductions, approximately 250 mGal, from both observations and modelling, encompassing the highest positive maximum on the overriding plates and the negative minimum on the trench, the trough is wider for the ocean–ocean subduction: approximately 300 km compared to approximately 180 km for the ocean–continent subduction. Furthermore, the gravitational disturbance pattern is more symmetric for the ocean–ocean subduction compared to the ocean–continent subduction in terms of the amplitudes of the two positive maxima over the overriding and subducting plates. Their difference is, for the ocean–ocean type, approximately one half of the ocean–continent one. These different characteristics of the two types of subductions are exploited herein in terms of the different crustal thicknesses of the overriding plate and of the different dynamics in the wedge and in the mantle for the two types of subduction, in close agreement with the gravity data.
The earliest arbitration treaty? A reassessment of the Anglo-Norman treaty of 991*
Authors: Benham Jenny
Published: January 2020

Concluded at Rouen in March 991, the Anglo-Norman treaty has traditionally occupied a very small corner of the huge historiography for King Æthelred’s reign as one of the first of the king’s failures to deal with the threat of renewed viking raids. This article is an attempt to rethink the place and importance of this treaty in the scholarly literature by looking at it from the perspective of how diplomacy was practised in the earlier middle ages. It reveals the treaty as the earliest arbitration treaty in the medieval West and offers alternative ways of viewing the immediate context and circumstances of the negotiations, as well as the persistence of important diplomatic practices across a long period.
Retinal degeneration in mice expressing the constitutively active G90D rhodopsin mutant
Authors: Colozo Alejandro T , Vasudevan Sreelakshmi , Park Paul S-H
Published: January 2020

Rhodopsin is the G protein-coupled receptor in rod photoreceptor cells that initiates vision upon photon capture. The light receptor is normally locked in an inactive state in the dark by the covalently bound inverse agonist 11-cis retinal. Mutations can render the receptor active even in the absence of light. This constitutive activity can desensitize rod photoreceptor cells and lead to night blindness. A G90D mutation in rhodopsin causes the receptor to be constitutively active and leads to congenital stationary night blindness, which is generally thought to be devoid of retinal degeneration. The constitutively active species responsible for the night blindness phenotype is unclear. Moreover, the classification as a stationary disease devoid of retinal degeneration is also misleading. A transgenic mouse model for congenital stationary night blindness that expresses the G90D rhodopsin mutant was examined to better understand the origin of constitutive activity and the potential for retinal degeneration. Heterozygous mice for the G90D mutation did not exhibit retinal degeneration whereas homozygous mice exhibited progressive retinal degeneration. Only a modest reversal of retinal degeneration was observed when transducin signaling was eliminated genetically, indicating that some of the retinal degeneration occurred in a transducin-independent manner. Biochemical studies on purified rhodopsin from mice indicated that multiple species can potentially contribute to the constitutive activity causing night blindness.
A Novel Synthetic Interfering Peptide Tat-3L4F Attenuates Olanzapine-Induced Weight Gain Through Disrupting Crosstalk Between Serotonin Receptor 2C and Protein Phosphatase and Tensin Homolog in Rats
Authors: Wang Yewei , Wang Dandan , Chen Yan , Fang Xinyu , Yu Lingfang , Zhang Chen
Published: January 2020

Background

Accompanied with profound efficacy, atypical antipsychotics (AAPs) contribute to metabolic adverse effects with few effective strategies to attenuate. Serotonin 5-HT2C receptor (HTR2C) plays a critical role in hyperphagia and weight gain induced by AAPs, and expression of phosphatase tensin homolog (PTEN) in the hypothalamus also affects feeding behavior and weight change. Moreover, PTEN has a physical crosstalk between PTEN and a region in the third intracellular loop (3L4F) of the HTR2C. Tat-3L4F has the property to disrupt crosstalk between PTEN and HTR2C. This is the first study to our knowledge to investigate the effect of Tat-3L4F on olanzapine-induced metabolic abnormalities and PTEN/ phosphatidylinositol 3-kinase/protein kinase B expression in the hypothalamus in rats.

Methods

The effects of Tat-3L4F were investigated through measuring body weight, food intake, and blood glucose. In addition, PTEN/phosphatidylinositol 3-kinase/protein kinase B level in the hypothalamus was detected by immunofluorescence assay and western blot. Metabolites in the liver tissue were detected by liquid chromatography-mass spectrometry and analyzed by multivariate analyses and pairwise comparison.

Results

Our results showed that hyperphagia and weight gain were evident in the olanzapine alone–fed rats but was attenuated after Tat-3L4F treatment. In addition, oral glucose tolerance test indicated blood glucose at 120 minutes was higher in the olanzapine alone–treated group than in groups treated with vehicle and olanzapine + Tat-3L4F (10 μmol kg−1 per day). Furthermore, compared with olanzapine alone treatment, treatment with Tat-3L4F (10 μmol kg−1 per day) significantly inhibited PTEN expression in the hypothalamus. The olanzapine alone–treated group had the highest bile acid level, followed by the olanzapine with Tat-3L4F (1 μmol kg−1) group, olanzapine with Tat-3L4F (10 μmol kg−1) group, and vehicle group.

Conclusions

Our present results reveal that Tat-3L4F is a potential pharmacological strategy for suppressing hyperphagia and weight gain induced by olanzapine, which acts through disrupting crosstalk between HTR2C and PTEN as a result of PTEN downregulation in the hypothalamus.
Non-Commutative Crepant Resolutions for Some Toric Singularities I
Authors: Špenko Špela , Van den Bergh Michel
Published: January 2020

We give a criterion for the existence of noncommutative crepant resolutions (NCCRs) for certain toric singularities. In particular, we recover Broomhead’s result that a three-dimensional toric Gorenstein singularity has an NCCR. Our result also yields the existence of an NCCR for a four-dimensional toric Gorenstein singularity, which is known to have no toric NCCR.
The Lazarus Effect and the Labour Market: Evidence from At-Scale Antiretroviral Therapy in Zambia
Authors: Wilson Nicholas
Published: January 2020

Between 2000 and 2015, access to life-saving antiretroviral therapy (ART) in sub-Saharan Africa increased from virtually 0% to approximately 40% coverage. Despite the promise of ART to improve health, a variety of supply- and demand-side factors suggest at-scale ART may not improve employment outcomes. To measure the causal effect of ART on employment outcomes, I use triple-difference regression analysis, exploiting spatial, temporal and demographic variation in intensity of ART exposure during scale-up in Zambia. My results suggest that local ART introduction increased employment of likely HIV+ adults by eight percentage points, or approximately 15% relative to the sample mean. Cash employment and employment for no pay—the first and second largest employment categories in Zambia, respectively—each comprised roughly one-half of the employment gains. Temporal and spatial heterogeneity analyses support a causal interpretation of the results. These findings appear to be the first at-scale quasi-experimental evidence suggesting that ART, the single largest item in many countries’ foreign health aid budgets, can improve employment outcomes among the targeted.
Structure of HIRAN domain of human HLTF bound to duplex DNA provides structural basis for DNA unwinding to initiate replication fork regression
Authors: Hishiki Asami , Sato Mamoru , Hashimoto Hiroshi
Published: January 2020

Replication fork regression is a mechanism to rescue a stalled fork by various replication stresses, such as DNA lesions. Helicase-like transcription factor, a SNF2 translocase, plays a central role in the fork regression and its N-terminal domain, HIRAN (HIP116 and Rad5 N-terminal), binds the 3’-hydroxy group of single-stranded DNA. Furthermore, HIRAN is supposed to bind double-stranded DNA (dsDNA) and involved in strand separation in the fork regression, whereas structural basis for mechanisms underlying dsDNA binding and strand separation by HIRAN are still unclear. Here, we report the crystal structure of HIRAN bound to duplex DNA. The structure reveals that HIRAN binds the 3’-hydroxy group of DNA and unexpectedly unwinds three nucleobases of the duplex. Phe-142 is involved in the dsDNA binding and the strand separation. In addition, the structure unravels the mechanism underlying sequence-independent recognition for purine bases by HIRAN, where the N-glycosidic bond adopts syn conformation. Our findings indicate direct involvement of HIRAN in the fork regression by separating of the daughter strand from the parental template.
Bicarbonate enhances the inflammatory response by activating JAK/STAT signalling in LPS + IFN-γ-stimulated macrophages
Authors: Kawakami Tomoya , Koike Atsushi , Maehara Toko , Hayashi Tetsuya , Fujimori Ko
Published: January 2020

Macrophages, which develop by changing their functions according to various environmental conditions and stimuli, defend against the pathogens and play roles in homoeostasis and disease states. Bicarbonate (HCO3−) is important in the maintenance of intracellular and extracellular pH in the body. However, the effects of bicarbonate on macrophage function have not been examined. In this study, we investigated the effects of bicarbonate on macrophage activation in lipopolysaccharide (LPS) and interferon (IFN)-γ (LPS + IFN-γ)-stimulated murine macrophage-like RAW264.7 cells. The expression of the interleukin (IL)-6, inducible nitric oxide (NO) synthase and cyclooxygenase-2 genes was enhanced by sodium bicarbonate (NaHCO3) in a concentration-dependent manner in LPS + IFN-γ-stimulated RAW264.7 cells. The production of IL-6, NO2− and prostaglandin E2 was also increased by treatment with NaHCO3 in these cells. Moreover, NaHCO3-mediated elevation of inflammatory gene expression was abrogated by solute carrier (SLC) transporter inhibitors. Furthermore, its NaHCO3-mediated activation was negated by a JAK inhibitor , tofacitinib. NaHCO3-enhanced phosphorylation of STAT1, and its enhancement was abrogated by pre-treating with SLC transporter inhibitors in LPS + IFN-γ-stimulated RAW264.7 cells. In addition, similar results were obtained in murine bone marrow-derived macrophages. These results indicate that bicarbonate enhanced the inflammatory response through the JAK/STAT signalling in LPS + IFN-γ-stimulated macrophages.
“Homes away from Home” and “Happy Prisoners”: Disabled Veterans, Space, and Masculinity in Britain, 1944–19501
Authors: Anderson Julie
Published: January 2020

This article examines the changing nature of home for disabled ex-servicemen in the Second World War. It explores the function of institutional and domestic space in the restoration of traditional male roles. Masculine activities were encouraged in the long-stay institution, as men attempted to overcome their disability and be found suitable to resume a place in a traditional domestic home. Owing to war damage, finding housing was particularly challenging for disabled men, but a combination of the influence of the British Legion, donations from the public, and their preference to memorialize the war through the building of homes increased the possibility of living in a traditional domestic space. The building, alteration, and occupation of homes reinforced certain modes of behavior and expectations of disabled veterans, cementing the central, traditional role of men in postwar Britain. Importantly, freedom from institutional living came through traditional relationships with women and the production of children. This analysis of the home in its many configurations offers insight into disabled ex-servicemen, demonstrating that the institutional and domestic spaces that constitute home are as important in understanding masculinity as other traditionally gendered spaces such as the workplace.
Same same, but different: growth responses of primary and lateral roots
Authors: Waidmann Sascha , Sarkel Elizabeth , Kleine-Vehn Jürgen
Published: January 2020

The root system architecture describes the shape and spatial arrangement of roots within the soil. Its spatial distribution depends on growth and branching rates as well as directional organ growth. The embryonic primary root gives rise to lateral (secondary) roots, and the ratio of both root types changes over the life span of a plant. Most studies have focused on the growth of primary roots and the development of lateral root primordia. Comparably less is known about the growth regulation of secondary root organs. Here, we review similarities and differences between primary and lateral root organ growth, and emphasize particularly how external stimuli and internal signals differentially integrate root system growth.
Advance Research Directives: Legal and Ethical Issues and Insights from a National Survey of Dementia Researchers in Australia
Authors: Ries Nola M , Mansfield Elise , Sanson-Fisher Rob
Published: January 2020

Advance research directives (ARDs) are a means by which people can document their wishes about research participation in the event of future incapacity. ARDs have been endorsed in some ethics guidelines and position statements, however, formal legal recognition is limited. A few empirical studies have investigated the views of researchers and other stakeholders on ARDs and tested strategies to implement such directives. To further knowledge in this area, we undertook a survey of dementia researchers in Australia (n= 63) to examine their views on ARDs. Most of the survey respondents (>80%) thought ARDs would promote autonomy in decision-making and enable opportunities for people with cognitive impairment to be included in research. Respondents indicated concern about directives not being available when needed (71%) and that ethics committees would not accept ARDs (60%). Few respondents had used ARDs, but a majority (from 57–80%) would be willing to offer ARDs for a range of research activities, such as observing behaviour and taking measures, blood samples or scans. Nearly all respondents (92%) agreed that current dissent should override prior wishes stated in an ARD. The survey findings are contextualised with attention to ethics guidelines, laws and practices to support advance research planning.
Globular cluster ejection, infall, and the host dark matter halo of the Pegasus dwarf galaxy
Authors: Leaman Ryan , Ruiz-Lara Tomás , Cole Andrew A , Beasley Michael A , Boecker Alina , Fahrion Katja , Bianchini Paolo , Falcón-Barroso Jesus , Webb Jeremy , Sills Alison , Mastrobuono-Battisti Alessandra , Neumayer Nadine , Sippel Anna C
Published: January 2020

Recent photometric observations revealed a massive, extended (MGC ≳ 105 M⊙; Rh ∼ 14 pc) globular cluster (GC) in the central region (D3D ≲ 100 pc) of the low-mass (M* ∼ 5 × 106 M⊙) dwarf irregular galaxy Pegasus. This massive GC offers a unique opportunity to study star cluster inspiral as a mechanism for building up nuclear star clusters, and the dark matter (DM) density profile of the host galaxy. Here, we present spectroscopic observations indicating that the GC has a systemic velocity of ΔV = 3 ± 8 km s−1 relative to the host galaxy, and an old, metal-poor stellar population. We run a suite of orbital evolution models for a variety of host potentials (cored to cusped) and find that the GC’s observed tidal radius (which is ∼3 times larger than the local Jacobi radius), relaxation time, and relative velocity are consistent with it surviving inspiral from a distance of Dgal ≳ 700 pc (up to the maximum tested value of Dgal = 2000 pc). In successful trials, the GC arrives to the galaxy centre only within the last ∼1.4 ± 1 Gyr. Orbits that arrive in the centre and survive are possible in DM haloes of nearly all shapes, however to satisfy the GC’s structural constraints a galaxy DM halo with mass MDM ≃ 6 ± 2 × 109 M⊙, concentration c ≃ 13.7 ± 0.6, and an inner slope to the DM density profile of −0.9 ≤ γ ≤ −0.5 is preferred. The gas densities necessary for its creation and survival suggest the GC could have formed initially near the dwarf’s centre, but then was quickly relocated to the outskirts where the weaker tidal field permitted an increased size and relaxation time – with the latter preserving the former during subsequent orbital decay.
Negative dynamical friction on compact objects moving through dense gas
Authors: Gruzinov Andrei , Levin Yuri , Matzner Christopher D
Published: January 2020

An overdense wake is created by a gravitating object moving through a gaseous medium, and this wake pulls back on the object and slows it down. This is conventional dynamical friction in a gaseous medium. We argue that if the object drives a sufficiently powerful outflow, the wake is destroyed and instead an extended underdense region is created behind the object. In this case the overall gravitational force is applied in the direction of the object’s motion, producing a negative dynamical friction (NDF). Black holes in dense gas drive powerful outflows and may experience the NDF, although extensive numerical work is probably needed to demonstrate or refute this conclusively. NDF may be important for stellar-mass black holes and neutron stars inside ‘common envelopes’ in binary systems, for stellar mass black holes inside active galactic nucleus discs, or for massive black holes growing through super-Eddington accretion in early Universe.
Baryon acoustic oscillations signature in the three-point angular correlation function from the SDSS-DR12 quasar survey
Authors: de Carvalho E , Bernui A , Xavier H S , Novaes C P
Published: January 2020

The clustering properties of the Universe at large scales are currently being probed at various redshifts through several cosmological tracers and with diverse statistical estimators. Here we use the three-point angular correlation function (3PACF) to probe the baryon acoustic oscillation (BAO) features in the quasars catalogue from the Sloan Digital Sky Survey Data Release 12, with mean redshift $\overline{z} = 2.225$, detecting the BAO imprint with a statistical significance of $2.9 \sigma$, obtained using lognormal mocks. Following a quasi-model-independent approach for the 3PACF, we find the BAO transversal signature for triangles with sides θ1 = $1{^{\circ}_{.}}0$ and θ2 = $1{^{\circ}_{.}}5$ and the angle between them of α = 1.59 ± 0.17 rad, a value that corresponds to the angular BAO scale $\theta_{\rm BAO}=1{^{\circ}_{.}}82 \pm 0{^{\circ}_{.}}21$, in excellent agreement with the value found in a recent work ($\theta_{\rm BAO}=1{^{\circ}_{.}}77 \pm 0{^{\circ}_{.}}31$) applying the two-point angular correlation function (2PACF) to similar data. Moreover, we performed two types of test: one to confirm the robustness of the BAO signal in the 3PACF through random displacements in the data set, and the other to verify the suitability of our random samples, a null test that in fact does not show any signature that could bias our results.
Type Ic supernova of a 22 M⊙ progenitor
Authors: Teffs Jacob , Ertl Thomas , Mazzali Paolo , Hachinger Stephan , Janka Thomas
Published: January 2020

Type Ic supernovae (SNe Ic) are a sub-class of core-collapse SNe that exhibit no helium or hydrogen lines in their spectra. Their progenitors are thought to be bare carbon–oxygen cores formed during the evolution of massive stars that are stripped of their hydrogen and helium envelopes sometime before collapse. SNe Ic present a range of luminosities and spectral properties, from luminous GRB-SNe with broad-lined spectra to less luminous events with narrow-line spectra. Modelling SNe Ic reveals a wide range of both kinetic energies, ejecta masses, and 56Ni masses. To explore this diversity and how it comes about, light curves and spectra are computed from the ejecta following the explosion of an initially 22 M⊙ progenitor that was artificially stripped of its hydrogen and helium shells, producing a bare CO core of ∼5 M⊙, resulting in an ejected mass of ∼4 M⊙, which is an average value for SNe Ic. Four different explosion energies are used that cover a range of observed SNe. Finally, 56Ni and other elements are artificially mixed in the ejecta using two approximations to determine how element distribution affects light curves and spectra. The combination of different explosion energy and degree of mixing produces spectra that roughly replicate the distribution of near-peak spectroscopic features of SNe Ic. High explosion energies combined with extensive mixing can produce red, broad-lined spectra, while minimal mixing and a lower explosion energy produce bluer, narrow-lined spectra.
Deep learning dark matter map reconstructions from DES SV weak lensing data
Authors: Jeffrey Niall , Lanusse François , Lahav Ofer , Starck Jean-Luc
Published: January 2020

We present the first reconstruction of dark matter maps from weak lensing observational data using deep learning. We train a convolution neural network with a U-Net-based architecture on over 3.6 × 105 simulated data realizations with non-Gaussian shape noise and with cosmological parameters varying over a broad prior distribution. We interpret our newly created dark energy survey science verification (DES SV) map as an approximation of the posterior mean P(κ|γ) of the convergence given observed shear. Our DeepMass1 method is substantially more accurate than existing mass-mapping methods. With a validation set of 8000 simulated DES SV data realizations, compared to Wiener filtering with a fixed power spectrum, the DeepMass method improved the mean square error (MSE) by 11 per cent. With N-body simulated MICE mock data, we show that Wiener filtering, with the optimal known power spectrum, still gives a worse MSE than our generalized method with no input cosmological parameters; we show that the improvement is driven by the non-linear structures in the convergence. With higher galaxy density in future weak lensing data unveiling more non-linear scales, it is likely that deep learning will be a leading approach for mass mapping with Euclid and LSST.
BAL and non-BAL quasars: continuum, emission, and absorption properties establish a common parent sample
Authors: Rankine Amy L , Hewett Paul C , Banerji Manda , Richards Gordon T
Published: January 2020

Using a sample of ≃144 000 quasars from the Sloan Digital Sky Survey Data Release 14, we investigate the outflow properties, evident in both absorption and emission, of high-ionization broad absorption line (BAL) and non-BAL quasars with redshifts 1.6 ≲ $z$ ≤ 3.5 and luminosities 45.3 erg s−1 < log10(Lbol) < 48.2 erg s−1. Key to the investigation is a continuum and emission-line reconstruction scheme, based on mean-field independent component analysis, that allows the kinematic properties of the C iv λ1550 emission line to be compared directly for both non-BAL and BAL quasars. C iv emission blueshift and equivalent width (EW) measurements are thus available for both populations. Comparisons of the emission-line and BAL trough properties reveal strong systematic correlations between the emission and absorption properties. The dependence of quantitative outflow indicators on physical properties such as quasar luminosity and luminosity relative to Eddington luminosity is also shown to be essentially identical for the BAL and non-BAL populations. There is an absence of BALs in quasars with the hardest spectral energy distributions (SEDs), revealed by the presence of strong He ii λ1640 emission, large C iv λ1550 emission EW, and no measurable blueshift. In the remainder of the C iv emission blueshift versus EW space, BAL and non-BAL quasars are present at all locations; for every BAL quasar, it is possible to identify non-BAL quasars with the same emission-line outflow properties and SED hardness. The co-location of BAL and non-BAL quasars as a function of emission-line outflow and physical properties is the key result of our investigation, demonstrating that (high-ionization) BALs and non-BALs represent different views of the same underlying quasar population.
Quasi-periodic behaviour in the optical and γ-ray light curves of blazars 3C 66A and B2 1633+38
Authors: Otero-Santos J , Acosta-Pulido J A , Becerra González J , Raiteri C M , Larionov V M , Peñil P , Smith P S , Ballester Niebla C , Borman G A , Carnerero M I , Castro Segura N , Grishina T S , Kopatskaya E N , Larionova E G , Morozova D A , Nikiforova A A , Savchenko S S , Troitskaya Yu V , Troitsky I S , Vasilyev A A , Villata M
Published: January 2020

We report on quasi-periodic variability found in two blazars included in the Steward Observatory Blazar Monitoring data sample: the BL Lac object 3C 66A and the Flat Spectrum Radio Quasar B2 1633+38. We collect optical photometric and polarimetric data in V and R bands of these sources from different observatories: St. Petersburg University, Crimean Astrophysical Observatory, WEBT–GASP, Catalina Real-Time Transient Survey, Steward Observatory, STELLA Robotic Observatory, and Katzman Automatic Imaging Telescope. In addition, an analysis of the γ-ray light curves from Fermi–LAT is included. Three methods are used to search for any periodic behaviour in the data: the Z-transform Discrete Correlation Function, the Lomb–Scargle periodogram and the Weighted Wavelet Z-transform. We find pieces of evidence of possible quasi-periodic variability in the optical photometric data of both sources with periods of ∼3 yr for 3C 66A and ∼1.9 yr for B2 1633+38, with significances between 3σ and 5σ. Only B2 1633+38 shows evidence of this behaviour in the optical polarized data set at a confidence level of 2σ–4σ. This is the first reported evidence of quasi-periodic behaviour in the optical light curve of B2 1633+38. Also, a hint of quasi-periodic behaviour is found in the γ-ray light curve of B2 1633+38 with a confidence level ≥2σ, while no periodicity is observed for 3C 66A in this energy range. We propose different jet emission models that could explain the quasi-periodic variability and the differences found between these two sources.
High-redshift JWST predictions from IllustrisTNG: dust modelling and galaxy luminosity functions
Authors: Vogelsberger Mark , Nelson Dylan , Pillepich Annalisa , Shen Xuejian , Marinacci Federico , Springel Volker , Pakmor Rüdiger , Tacchella Sandro , Weinberger Rainer , Torrey Paul , Hernquist Lars
Published: January 2020

The James Webb Space Telescope (JWST) promises to revolutionize our understanding of the early Universe, and contrasting its upcoming observations with predictions of the Λ cold dark matter model requires detailed theoretical forecasts. Here, we exploit the large dynamic range of the IllustrisTNG simulation suite, TNG50, TNG100, and TNG300, to derive multiband galaxy luminosity functions from z = 2 to z = 10. We put particular emphasis on the exploration of different dust attenuation models to determine galaxy luminosity functions for the rest-frame ultraviolet (UV), and apparent wide NIRCam bands. Our most detailed dust model is based on continuum Monte Carlo radiative transfer calculations employing observationally calibrated dust properties. This calibration results in constraints on the redshift evolution of the dust attenuation normalization and dust-to-metal ratios yielding a stronger redshift evolution of the attenuation normalization compared to most previous theoretical studies. Overall we find good agreement between the rest-frame UV luminosity functions and observational data for all redshifts, also beyond the regimes used for the dust model calibrations. Furthermore, we also recover the observed high-redshift (z = 4–6) UV luminosity versus stellar mass relation, the H α versus star formation rate relation, and the H α luminosity function at z = 2. The bright end (MUV > −19.5) cumulative galaxy number densities are consistent with observational data. For the F200W NIRCam band, we predict that JWST will detect ∼80 (∼200) galaxies with a signal-to-noise ratio of 10 (5) within the NIRCam field of view, $2.2\times 2.2 \, {\rm arcmin}^{2}$, for a total exposure time of $10^5\, {\rm s}$ in the redshift range z = 8 ± 0.5. These numbers drop to ∼10 (∼40) for an exposure time of $10^4\, {\rm s}$.
Tidal disruption of planetary bodies by white dwarfs I: a hybrid sph-analytical approach
Authors: Malamud Uri , Perets Hagai B
Published: January 2020

We introduce a new hybrid method to perform high-resolution tidal disruption simulations, at arbitrary orbits. An sph code is used to simulate tidal disruptions only in the immediate spatial domain of the star, namely, where the tidal forces dominate over gravity, and then during the fragmentation phase in which the emerging tidal stream may collapse under its own gravity to form fragments. Following each hydrodynamical simulation, an analytical treatment is then applied to instantaneously transfer each fragment back to the tidal sphere for its subsequent disruption, in an iterative process. We validate the hybrid model by comparing it to both an analytical impulse approximation model of single tidal disruptions, as well as full-scale sph simulations spanning the entire disc formation. The hybrid simulations are essentially indistinguishable from the full-scale sph simulations, while computationally outperforming their counterparts by orders of magnitude. Thereby our new hybrid approach uniquely enables us to follow the long-term formation and continuous tidal disruption of the planet/planetesimal debris, without the resolution and orbital configuration limitation of previous studies. In addition, we describe a variety of future directions and applications for our hybrid model, which is in principle applicable to any star, not merely white dwarfs.
Tidal disruption of planetary bodies by white dwarfs – II. Debris disc structure and ejected interstellar asteroids
Authors: Malamud Uri , Perets Hagai B
Published: January 2020

We make use of a new hybrid method to simulate the long-term, multiple-orbit disc formation through tidal disruptions of rocky bodies by white dwarfs, at high-resolution and realistic semimajor axis. We perform the largest yet suite of simulations for dwarf and terrestrial planets, spanning four orders of magnitude in mass, various pericentre distances, and semimajor axes between 3 and 150 au. This large phase space of tidal disruption conditions has not been accessible through the use of previous codes. We analyse the statistical and structural properties of the emerging debris discs, as well as the ejected unbound debris contributing to the population of interstellar asteroids. Unlike previous tidal disruption studies of small asteroids which form ring-like structures on the original orbit, we find that the tidal disruption of larger bodies usually forms dispersed structures of interlaced elliptic eccentric annuli on tighter orbits. We characterize the (typically power law) size distribution of the ejected interstellar bodies as well as their composition, rotation velocities, and ejection velocities. We find them to be sensitive to the depth (impact parameter) of the tidal disruption. Finally, we briefly discuss possible implications of our results in explaining the peculiar variability of Tabby’s star, the origin of the transit events of ZTF J0139+5245 and the formation of a planetary core around SDSS J1228+1040.