bluuebunny/crossref_metadata_2025 huggingface dataset:
Enabling Militarism? The Inclusion of Soldiers with Disabilities in the Israeli Military
Authors: Eastwood James
Published: September 2019

Soldiers are rarely imagined as having disabilities, other than when they are injured in war. Yet in recent years the Israeli military has devoted considerable resources to programs promoting the inclusion of soldiers with intellectual disabilities. This paper critically examines two such programs, arguing that they should prompt a reexamination of assumptions in both critical military studies and critical disability studies. These two fields are rarely placed in dialogue, especially in international relations. Yet this paper argues that they have productive insights to offer each other and suggests that the Israeli case raises important questions when their analytical frames are combined. First, the paper argues that this example complicates the category of soldier fitness in critical military studies and reveals that militarist distinctions between ability and disability can be destabilized in ways suggested elsewhere by critical disability studies. Second, however, the paper cautions that the emancipatory potential of alternative “crip” subjectivities explored in critical disability studies remains circumscribed by geopolitical processes (including neoliberalism, settler colonialism, and militarism), which international relations is well placed to analyze. These arguments are advanced by showing how these inclusionary programs for soldiers with disabilities are implicated in the debilitating violence of Israel's settler colonial project.
The effectiveness of repeating a social norm feedback intervention to high prescribers of antibiotics in general practice: a national regression discontinuity design
Authors: Ratajczak Michael , Gold Natalie , Hailstone Simon , Chadborn Tim
Published: September 2019

Objectives

Unnecessary antibiotic prescribing contributes to antimicrobial resistance. A randomized controlled trial in 2014–15 showed that a letter from England’s Chief Medical Officer (CMO) to high-prescribing GPs, giving feedback about their prescribing relative to the norm, decreased antibiotic prescribing. The CMO sent further feedback letters in succeeding years. We evaluated the effectiveness of the repeated feedback intervention.

Methods

Publicly available databases were used to identify GP practices whose antibiotic prescribing was in the top 20% nationally (the intervention group). In April 2017, GPs in every practice in the intervention group (n=1439) were sent a letter from the CMO. The letter stated that, ‘the great majority of practices in England prescribe fewer antibiotics per head than yours’. Practices in the control group received no communication (n=5986). We used a regression discontinuity design to evaluate the intervention because assignment to the intervention condition was exogenous, depending on a ‘rating variable’. The outcome measure was the average rate of antibiotic items dispensed from April 2017 to September 2017.

Results

The GP practices who received the letter changed their prescribing rates by −3.69% (95% CI=−2.29 to −5.10; P<0.001), representing an estimated 124 952 fewer antibiotic items dispensed. The effect is robust to different specifications of the model.

Conclusions

Social norm feedback from a high-profile messenger continues to be effective when repeated. It can substantially reduce antibiotic prescribing at low cost and on a national scale. Therefore, it is a worthwhile addition to antimicrobial stewardship programmes.
Metabolite Profiling of Ortho-, Meta- and Para-Fluorofentanyl by Hepatocytes and High-Resolution Mass Spectrometry
Authors: Gundersen Per Ole M , Åstrand Anna , Gréen Henrik , Josefsson Martin , Spigset Olav , Vikingsson Svante
Published: September 2019

New psychoactive substances are emerging on the illegal drug market. Synthetic opioids including fentanyl analogues are of special concern due to their high potency. This indicates the possibility of low drug concentrations in vivo and calls for sensitive analytical methods and identification of the most appropriate analytical targets. In this study the in vitro metabolism of ortho-, meta- and para-fluorofentanyl, three fluorinated derivatives of fentanyl, has been investigated using human hepatocytes and compared to the results from an authentic human urine sample. Based on knowledge on the metabolism of similar fentanyl analogues N-dealkylation and hydroxylation was hypothesized to be the most central pathways. The three fluorofentanyl isomers were incubated with pooled human hepatocytes at 1, 3 and 5 h. Liquid chromatography quadrupole time of flight mass spectrometry operating in data-dependent mode was used to analyse the hepatocyte samples, as well as the hydrolysed and non-hydrolysed authentic urine sample. Data were analysed by a targeted approach with a database of potential metabolites. The major metabolite formed in vitro was the N-dealkylation product norfluorofentanyl. In addition various hydroxylated metabolites, a N-oxide, dihydrodiol metabolites and a hydroxymethoxy metabolite were found. In total, 14 different metabolites were identified for each fluorofentanyl isomer. In the authentic urine sample, three metabolites were detected in addition to the ortho-fluorofentanyl parent compound, with hydroxymethoxy metabolite having the highest abundance followed by norfluorofentanyl and a metabolite hydroxylated on the ethylphenyl ring. This in vitro study showed that the metabolic pattern for ortho-, meta-, and para-fluorofentanyl was close to those previously reported for other fentanyl analogues. We suggest that the hydroxymethoxy metabolite and the metabolite hydroxylated on the ethylphenyl ring should be the metabolites primarily investigated in further studies to determine the most appropriate marker for intake of fluorofentanyl derivatives in urine drug screening for human subjects.
Determination of Ethyl Glucuronide and Ethyl Sulfate in Human Whole Blood and Vitreous Humor by LC–MS-MS and Applications to the Interpretation of Postmortem Ethanol Findings
Authors: Wang Hao , Li Beixu , Wang Fanglin , Chang Jing , Zhang Yunfeng , Rao Yulan
Published: September 2019

Identifying the source of ethanol in a decedent remained a complicated problem for forensic toxicologists because of postmortem ethanol formation. As ethanol’s non-oxidative metabolites, ethyl glucuronide (EtG) and ethyl sulfate (EtS) have the potential to distinguish between antemortem ethanol consumption and postmortem ethanol formation, due to their high sensitivity and selectivity. In the current study, a simple and quick liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for the determination of EtG and EtS in human whole blood and vitreous humor (VH). A total of 20 μL of the sample was precipitated by methanol, and the analytes were detected by LC-MS/MS in a run of 6 min. This method achieved high sensitivity (limits of detection: 2 ng/mL for both EtG and EtS), with linearity in the range of 5–10,000 ng/mL in both whole blood and VH. Deviations in accuracy, inter- and intra-day precision were all lower than 15% at three quality control levels. Subsequently, this method was applied to 62 real forensic cases. Only blood samples were available in 52 cases. Paired blood and VH samples were present in 10 cases. The concentrations of EtG and EtS in blood were in the range of 0–22,264.8 ng/mL and 0–2,126.0 ng/mL, respectively. In one case with both blood and VH, the blood ethanol concentration was 1.22 mg/mL, with EtG and EtS both below limits of quantification (5 ng/mL) in VH, and no EtG and EtS found in whole blood. The results suggested that EtG and EtS were useful markers for the interpretation of ethanol resource in postmortem blood and VH.
The Establishment Risk of Lycorma delicatula (Hemiptera: Fulgoridae) in the United States and Globally
Authors: Wakie Tewodros T , Neven Lisa G , Yee Wee L , Lu Zhaozhi
Published: September 2019

Native to Asia, the spotted lanternfly, Lycorma delicatula (White), is an emerging pest of many commercially important plants in Korea, Japan, and the United States. Determining its potential distribution is important for proactive measures to protect commercially important commodities. The objective of this study was to assess the establishment risk of L. delicatula globally and in the United States using the ecological niche model MAXENT, with a focus on Washington State (WA), where large fruit industries exist. The MAXENT model predicted highly suitable areas for L. delicatula in Asia, Oceania, South America, North America, Africa, and Europe, but also predicted that tropical habitats are not suitable for its establishment, contrary to published information. Within the United States, the MAXENT model predicted that L. delicatula can establish in most of New England and the mid-Atlantic states, the central United States and the Pacific Coast states, including WA. If introduced, L. delicatula is likely to establish in fruit-growing regions of the Pacific Northwest. The most important environmental variables for predicting the potential distribution of L. delicatula were mean temperature of driest quarter, elevation, degree-days with a lower developmental threshold value of 11°C, isothermality, and precipitation of coldest quarter. Results of this study can be used by regulatory agencies to guide L. delicatula surveys and prioritize management interventions for this pest.
To fuse, Not to Fuse, or Simply Confuse? Assessing the Case for Normative Convergence Between Goods and Services Trade Law
Authors: Sauvé Pierre
Published: September 2019

Goods and services were separated (politically) at birth when the Uruguay Round of multilateral negotiations was launched. The goods and services divide reflected in today’s structure of global trade governance has increasingly come into question in a world of cross-border production networks. This begs the question of the desirability and political economy feasibility of fusing the law of goods and services trade into one undifferentiated whole. This paper asks whether the current architectures of multilateral and preferential trade governance are compatible with a world of trade in tasks; whether existing rules offer globally active firms a coherent structure for doing business in a predictable environment; whether it is feasible to redesign the structure and content of existing trade rules to align them to the reality of production fragmentation; and what steps can be envisaged to better align policy with market realities if restructuring prospects appear unfavorable. The paper argues that fusing trade disciplines for goods and services is neither needed nor feasible and may actually deflect attention from a number of worthwhile policy initiatives where more realistic (if never easily secured) prospects of generic rule-making may well exist.
Dramatic response of FOLFIRINOX regimen in a collision pancreatic adenocarcinoma patient with a germline BRCA2 mutation: a case report
Authors: Shimmura Hideki , Kuramochi Hidekazu , Jibiki Norie , Katagiri Satoshi , Nishino Takayoshi , Araida Tatsuo
Published: September 2019

Germline BRCA1 and BRCA2 mutations are the most common gene mutations in familial pancreatic adenocarcinoma. Several reports have demonstrated the utility of platinum-based chemotherapy for treating cancer patients who harbour a BRCA mutation. Here we discuss a 47-year-old Japanese female with no relevant past history who presented with epigastralgia and fever in September 2016. A computed tomography scan revealed a low-density, low-enhanced tumour 15 mm in diameter in the head of the pancreas. The pathological diagnosis was a ductal pancreatic carcinoma. A 6 mm low-enhanced metastatic tumour was also detected in segment 4 of the liver. Because she had early onset of the disease and a family history—her mother died of pancreatic adenocarcinoma at age 48—we considered a diagnosis of familial pancreatic adenocarcinoma. She received modified FOLFIRINOX. Two months after starting chemotherapy, she was diagnosed with an invasive ductal carcinoma in the right breast. FOLFIRINOX was continued for 8 cycles (4 months); the primary pancreatic adenocarcinoma shrank and the liver metastatic foci disappeared, but the size of the breast tumour increased. Total right breast excision and sentinel lymph node dissection were performed. FOLFIRINOX was continued and after 12 cycles (6 months), both her pancreatic adenocarcinoma and liver metastasis were no longer visible using imaging. Pancreatoduodenectomy was performed and the primary tumour had shrunk to 2.5 mm. Genetic testing revealed a germline BRCA2 mutation. The FOLFIRINOX regimen showed dramatic effects on the collision pancreatic but not on the breast cancer.
A review of changes to and clinical implications of the eighth TNM classification of hepatobiliary and pancreatic cancers
Authors: Ueno Makoto , Morizane Chigusa , Ikeda Masafumi , Okusaka Takuji , Ishii Hiroshi , Furuse Junji
Published: September 2019

Hepatobiliary and pancreatic cancers have poor outcomes. Clinical staging is useful for predicting survival and selecting treatment options. The 8th edition of tumor-node metastasis (TNM) was published in 2016 and came into effect from 2018. Regarding liver cancer (hepatocellular carcinoma), tumour size and vascular invasion were more emphasized adding numbers. Tumour size was included for intrahepatic cholangiocarcinoma. T2 for gallbladder cancer was divided into two categories based on the side of invasion, and lymph node metastasis was classified according to the number of lymph nodes, not the site. The N category for perihilar cholangiocarcinoma was changed to the same as that for gallbladder cancer (total number of regional lymph nodes). The depth of tumour invasion using cut-off values of 5 and 12 mm was adopted as the T category for distal cholangiocarcinoma. The N category was also changed (the total number of regional lymph nodes). Regarding cancer of the ampulla of Vater, the T category was classified in more detail and the N category was also changed to the total number of regional lymph nodes. T1 for pancreatic cancer was separated into T1 subcategories (T1a, T1b and T1c) based on cut-off values of 5 and 10 mm. T1–T3 were classified with cut-off values of ≤2 cm, >2 to 4 cm and >4 cm. Furthermore, the N category was changed to the total number of regional lymph nodes. Although there are limitations due to treatment decisions only being based on imaging interpretation, this classification predicts the prognosis of patients more accurately than the previous edition.
Building Institutional Trust Through Service Experiences—Private Versus Public Provision Matter
Authors: Berg Monika , Johansson Tobias
Published: September 2019

Welfare service experiences are known to shape citizens' trust in public institutions and their support of the welfare state. But, there is poor understanding of how this relationship is shaped in systems of mixed provision, that is, welfare states that use public in-house as well as contracted private providers for publically funded services. Drawing on the notion of system trust this article provides a theoretical account of how mixed-provision welfare systems condition the relationship between service experience and trust, affecting the legitimacy of the state. Utilizing a randomized vignette experiment with participants in a general citizen survey in Sweden, we investigate whether it matters for the formation of institutional trust if the welfare service is provided by a public or third-party private provider. The main result show that the spillover of trust from positive service experiences with the provider to trust in public institutions is higher in cases of public service provision. Thus, the possibility of using welfare services to build trust in the welfare system seems to be greater when public provision is used.
Symptom Profiles of CD and ODD Among Youth With Perinatally Acquired HIV
Authors: Osigwe Ijeoma , Gadow Kenneth D , Nachman Sharon , Drabick Deborah A G
Published: September 2019

Objective

Youth with perinatally acquired human immunodeficiency virus (PHIV) face increased risk for conduct disorder (CD) and oppositional defiant disorder (ODD) symptoms, and heterogeneous findings indicate that there may be subgroups of youth with PHIV differing in the quality and/or frequency of symptoms. The present study examined symptom profiles of CD and ODD among youth with PHIV and whether profiles differed in terms of parent–child and family correlates.

Methods

Participants included 314 youth with PHIV, aged 6–17 years (M = 12.88 years, SD = 3.08; 51% male; 85% Black or Latinx), and their caregivers who were recruited from 29 clinics in the US involved in the International Maternal Pediatrics Adolescent AIDS Clinical Trials (IMPAACT) Group’s P1055 study. Caregivers reported on youth CD and ODD symptoms, parent–child interactions, and family environment.

Results

Latent class analysis indicated that a four-class model (i.e., moderate CD/high ODD, high ODD, moderate ODD, low CD/ODD) best fit the data. Ancillary analyses to validate these classes revealed differences for family cohesion and conflict; and child-centeredness, detachment, guilt-induced control, and consistency in parent–child interactions. The low CD/ODD class generally differed from other classes with additional differentiation between some higher risk profiles.

Conclusions

Findings suggest that homogeneous classes of CD/ODD symptoms can be identified among youth with PHIV, and these profiles differ in terms of family processes, consistent with previous work among chronically ill youth.
Towards a ‘client professionalization’ process? The case of the institutionalization of executive coaching in France
Authors: Salman Scarlett
Published: September 2019

Drawing on the ‘corporate professionalization’ model (Kipping, Kirkpatrick, and Muzio 2006; Muzio et al. 2011) of new strategies adopted by managerial occupations, this article explores professionalization processes taking into account the role of the client. Based on an analysis of the professionalization of executive coaching, it demonstrates the influence of the client organizations in such processes, at a collective and institutional level. This influence tends to favor new professionalization strategies of differentiation, regulation, and dissemination. The article suggests that this influence does not necessarily limit the power of corporate professionals, at least in the institutionalization phase, especially if we redefine power as consisting ‘not in restriction and exclusion, but in extension and linking’ (Eyal 2013: 876). Framed primarily to analyze corporate occupations practiced by independent professionals, the ‘client professionalization’ model suggests better taking into account the influence of client organizations in further research on professionalization processes, in line with the research conducted on ‘client capture’ (Leicht and Fennell 2001; Dinovitzer, Gunz, and Gunz, 2014). By studying an emergent corporate profession that is practiced by self-employed, solo practitioners and freelancers, which have been largely overlooked in the literature, this article contributes overall to a more diverse understanding of corporate professions and the ways in which they professionalize.
Radon (222Rn) concentrations in the touristic Jumandy cave in the Amazon region of Ecuador
Authors: García Paz Felipe Alejandro , Gonzalez Romero Yasser Alejandro , Zalakeviciute Rasa
Published: September 2019

This work consists of the detection and quantification of the concentration levels of radioactive gas radon-222 (222Rn) of natural origin, as well as the determination of the critical points and the estimation of the effective dose absorbed by the tourists and guides inside the Jumandy cavern in Napo, Ecuador. According to the feasibility map of uranium of Ecuador, the study area is located in one of the top-priority areas for obtaining uranium, suggesting possible radioactivity in this unstudied region. The measurements were carried out from July to October of 2017, in three different monitoring points inside the cavern. The average radon concentrations measured in the cavern exceeded the maximum recommended environmental level by a factor of 28, and the effective dose absorbed by the guides exceeded the recommended maximum by a f actor of 10. Meteorological parameters such as temperature and relative humidity have an impact on the 222Rn concentrations in different parts of the cave.
Does mentoring make immigrants more desirable? A conjoint analysis
Authors: Weiss Akiva , Tulin Marina
Published: September 2019

High levels of immigration to Germany have led to increased interests in integration programs. Yet, it is unclear to what extent immigrant participation in integration programs affects attitudes toward immigrants among the host population. This article measures which immigrant attributes German respondents find desirable, and how these features interact with participation in a mentoring program with a local mentor. Mentoring is often employed to aid immigrant integration and typically focuses on psychosocial, social capital, and employment-related goals. Our results show that Germans prefer traits conducive to gainful employment. While migrant ethnicity had no significant effect, migrant religion was salient. Muslim immigrants were preferred less than immigrants of other religions, and this effect was stronger among respondents living in areas with higher support for far-right politics. Participation in a mentoring program increased migrant desirability both directly and indirectly by mitigating the negative effects of having lower levels of education, little work experience, not speaking German and being Muslim.
Numerical simulations of the emerging plasma blob into a solar coronal hole
Authors: Navarro Anamaría , Murawski K , Wójcik D , Lora-Clavijo F D
Published: September 2019

We numerically simulate emergence of a magnetic plasma blob into a solar coronal hole. This blob may be associated with granulation and therefore it has a weak magnetic field. Two-dimensional simulations are performed using the magnus code which solves magnetohydrodynamic equations, taking into account magnetic resistivity and thermal conduction. As a result of the interaction of the emerging blob with the ambient plasma, the magnetic lines experience reconnection with the blob getting flattened and deformed with time. Additionally, this process launches a vertical outflow of hot plasma and the chromosphere in its response increases its temperature. We perform parametric studies by varying the magnitude of the magnetic field of the blob and observing the net heating of the chromosphere. These studies are inspired by realistic simulations of granulation made with the use of two-fluid joanna code. In these simulations a number of magnetic blobs are detected in the convection zone and in the photosphere. From the numerical results, we conclude that as a result of granulation operating in a solar quiet region the emerging blob may trigger very complex dynamics in the upper regions of the solar atmosphere, and the associated outflows may be a source of heating of the chromosphere and possibly the solar corona.
Balmer breaks in simulated galaxies at z>6
Authors: Binggeli Christian , Zackrisson Erik , Ma Xiangcheng , Inoue Akio K , Vikaeus Anton , Hashimoto Takuya , Mawatari Ken , Shimizu Ikkoh , Ceverino Daniel
Published: September 2019

Photometric observations of the spectroscopically confirmed z ≈ 9.1 galaxy MACS1149-JD1 have indicated the presence of a prominent Balmer break in its spectral energy distribution, which may be interpreted as due to very large fluctuations in its past star formation activity. In this paper, we investigate to what extent contemporary simulations of high-redshift galaxies produce star formation rate variations sufficiently large to reproduce the observed Balmer break of MACS1149-JD1. We find that several independent galaxy simulations are unable to account for Balmer breaks of the inferred size, suggesting that MACS1149-JD1 either must be a very rare type of object or that our simulations are missing some key ingredient. We present predictions of spectroscopic Balmer break strength distributions for z ≈ 7–9 galaxies that may be tested through observations with the upcoming James Webb Space Telescope and also discuss the impact that various assumptions on dust reddening, Lyman continuum leakage and deviations from a standard stellar initial mass function would have on the results.
Dark matter and no dark matter: on the halo mass of NGC 1052
Authors: Forbes Duncan A , Alabi Adebusola , Brodie Jean P , Romanowsky Aaron J
Published: September 2019

The NGC 1052 group, and in particular the discovery of two ultra-diffuse galaxies with very low internal velocity dispersions, has been the subject of much attention recently. Here we present radial velocities for a sample of 77 globular clusters associated with NGC 1052 obtained on the Keck telescope. Their mean velocity and velocity dispersion are consistent with that of the host galaxy. Using a simple tracer mass estimator, we infer the enclosed dynamical mass and dark matter fraction of NGC 1052. Extrapolating our measurements with a Navarro–Frenk–White (NFW) mass profile we infer a total halo mass of 6.2(±0.2) × 1012 M⊙. This mass is fully consistent with that expected from the stellar mass–halo mass relation, suggesting that NGC 1052 has a normal dark matter halo mass (i.e. it is not deficient in dark matter in contrast to two ultra-diffuse galaxies in the group). We present a phase-space diagram showing the galaxies that lie within the projected virial radius (390 kpc) of NGC 1052. Finally, we briefly discuss the two dark matter-deficient galaxies (NGC 1052-DF2 and NGC 1052-DF4) and consider whether modified Newtonian dynamics (MOND) can account for their low observed internal velocity dispersions.
Halo exclusion criteria impacts halo statistics
Authors: García Rafael , Rozo Eduardo
Published: September 2019

Every halo-finding algorithm must make a critical yet relatively arbitrary choice: it must decide which structures are parent haloes, and which structures are subhaloes of larger haloes. We refer to this choice as percolation. We demonstrate that the choice of percolation impacts the statistical properties of the resulting halo catalogue. Specifically, we modify the halo-finding algorithm rockstar to construct three different halo catalogues from the same simulation data, each with identical mass definitions, but different choice of percolation. The resulting haloes exhibit significant differences in both halo abundance and clustering properties. Differences in the halo mass function reach 6 per cent for haloes of mass $10^{13}\ h^{-1}\ {\rm {\rm M}_{\odot }}$, larger than the few per cent precision necessary for current cluster abundance experiments such as the Dark Energy Survey. Comparable differences are observed in the large-scale clustering bias, while differences in the halo–matter correlation function reach 30 per cent on translinear scales. These effects can bias weak-lensing estimates of cluster masses at a level comparable to the statistical precision of current state-of-the-art experiments.
Discovery of recombining plasma inside the extended gamma-ray supernova remnant HB9
Authors: Sezer A , Ergin T , Yamazaki R , Sano H , Fukui Y
Published: September 2019

We present the results from the Suzaku X-ray Imaging Spectrometer observation of the mixed-morphology supernova remnant (SNR) HB9 (G160.9+2.6). We discovered recombining plasma (RP) in the western Suzaku observation region and the spectra here are well described by a model having collisional ionization equilibrium (CIE) and RP components. On the other hand, the X-ray spectra from the eastern Suzaku observation region are best reproduced by the CIE and non-equilibrium ionization model. We discuss possible scenarios to explain the origin of the RP emission based on the observational properties and concluded that the rarefaction scenario is a possible explanation for the existence of RP. In addition, the gamma-ray emission morphology and spectrum within the energy range of 0.2–300 GeV are investigated using 10 yr of data from the Fermi Large Area Telescope (LAT). The gamma-ray morphology of HB9 is best described by the spatial template of radio continuum emission. The spectrum is well fit to a log-parabola function and its detection significance was found to be 25σ. Moreover, a new gamma-ray point source located just outside the south-east region of the SNR’s shell was detected with a significance of 6σ. We also investigated the archival H i and CO data and detected an expanding shell structure in the velocity range of $-10.5$ and $+1.8$ km s−1 that is coinciding with a region of gamma-ray enhancement at the southern rim of the HB9 shell.
The amplitude of the kilohertz quasi-periodic oscillations in 4U 1636–53 in the frequency-energy space
Authors: Ribeiro Evandro M , Méndez Mariano , de Avellar Marcio G B , Zhang Guobao , Karpouzas Konstantinos
Published: September 2019

We present for the neutron-star low-mass X-ray binary 4U 1636–53, and for the first time for any source of kilohertz quasi-periodic oscillations (kHz QPOs), the two-dimensional behaviour of the fractional rms amplitude of the kHz QPOs in the parameter space defined by QPO frequency and photon energy. We find that the rms amplitude of the lower kHz QPO increases with energy up to $\sim \!\!12$ keV and then decreases at higher energies, while the rms amplitude of the upper kHz QPO either continues increasing or levels off at high energies. The rms amplitude of the lower kHz QPO increases and then decreases with frequency, peaking at $\sim \!\!760$ Hz, while the amplitude of the upper kHz QPO decreases with frequency, with a local maximum at around $\sim \!\!770$ Hz, and is consistent with becoming zero at the same QPO frequency, $\sim \!\!1400$ Hz, in all energy bands, thus constraining the neutron-star mass at $M_{NS} \le 1.6 \, \mathrm{M}_{\odot }$, under the assumption that this QPO reflects the Keplerian frequency at the inner edge of the accretion disc. We show that the slope of the rms energy spectrum is connected to the changing properties of the kHz QPOs in different energy bands as its frequencies change. Finally, we discuss a possible mechanism responsible for the radiative properties of the kHz QPOs and, based on a model in which the QPO arises from oscillations in a Comptonizing cloud of hot electrons, we show that the properties of the kHz QPOs can constrain the thermodynamic properties of the inner accretion flow.
Orphaned exomoons: Tidal detachment and evaporation following an exoplanet–star collision
Authors: Martinez Miguel A S , Stone Nicholas C , Metzger Brian D
Published: September 2019

Gravitational perturbations on an exoplanet from a massive outer body, such as the Kozai–Lidov mechanism, can pump the exoplanet’s eccentricity up to values that will destroy it via a collision or strong interaction with its parent star. During the final stages of this process, any exomoons orbiting the exoplanet will be detached by the star’s tidal force and placed into orbit around the star. Using ensembles of three- and four-body simulations, we demonstrate that while most of these detached bodies either collide with their star or are ejected from the system, a substantial fraction, $\sim 10{{\ \rm per\ cent}}$, of such ‘orphaned’ exomoons (with initial properties similar to those of the Galilean satellites in our own Solar system) will outlive their parent exoplanet. The detached exomoons generally orbit inside the ice line, so that strong radiative heating will evaporate any volatile-rich layers, producing a strong outgassing of gas and dust, analogous to a comet’s perihelion passage. Small dust grains ejected from the exomoon may help generate an opaque cloud surrounding the orbiting body but are quickly removed by radiation blow-out. By contrast, larger solid particles inherit the orbital properties of the parent exomoon, feeding an eccentric disc of solids that drains more gradually on to the star via Poynting–Robertson drag, and which could result in longer time-scale dimming of the star. For characteristic exomoon evaporation times of ∼105–106 yr, attenuation of the stellar light arising from one or more out-gassing exomoons provides a promising explanation for both the dipping and secular dimming behaviour observed from KIC 8462852  (Boyajian’s Star).
Collision excitation of sodium cyanide molecule by helium at low temperature
Authors: Gharbi C , Ajili Y , Ben Abdallah D , Mogren Al Mogren M , Hochlaf M
Published: September 2019

Cyanides/isocyanides are the most common metal-containing molecules in interstellar medium. In this work, quantum scattering calculations were carried out to determine the rotational (de-)excitation cross-sections of the most stable form of the sodium cyanide molecule, t-NaCN, in collision with the helium atom. Rate coefficients for the first 43 rotational levels (up to ${j_{{K_a}{K_c}}}$ = 63,3) of NaCN were determined for kinetic temperatures ranging from 1 to 30 K. Prior to that, we constructed a new three-dimensional potential energy surface (3D-PES) for the t-NaCN–He interacting system. These electronic structure computations are done at the CCSD(T)-F12/aug-cc-pVTZ level of theory. Computations show the dominance of Δj = ΔKc = −1 transitions, which is related to the dissymmetric shape of the t-NaCN–He 3D-PES. The NaCN–He rate coefficients are of the same order of magnitude (∼10−11 cm3.s−1) as those of other metal CN-containing molecules such as MgCN and AlCN in collision with He. This work is a contribution for understanding and modelling the abundances and chemistry of nitriles in astrophysical media.
Diffuse ionized gas and its effects on nebular metallicity estimates of star-forming galaxies
Authors: Vale Asari N , Couto G S , Cid Fernandes R , Stasińska G , de Amorim A L , Ruschel-Dutra D , Werle A , Florido T Z
Published: September 2019

We investigate the impact of the diffuse ionized gas (DIG) on abundance determinations in star-forming (SF) galaxies. The DIG is characterized using the H α equivalent width (WH α). From a set of 1 409 SF galaxies from the Mapping Nearby Galaxies at APO (MaNGA) survey, we calculate the fractional contribution of the DIG to several emission lines using high-S/N data from SF spaxels (instead of using noisy emission-lines in DIG-dominated spaxels). Our method is applicable to spectra with observed WH α ≳ 10 Å (which are not dominated by DIG emission). Since the DIG contribution depends on galactocentric distance, we provide DIG-correction formulae for both entire galaxies and single aperture spectra. Applying those to a sample of $\, \gt 90\, 000$ SF galaxies from the Sloan Digital Sky Survey, we find the following. (1) The effect of the DIG on strong-line abundances depends on the index used. It is negligible for the ([O iii]/H β)/([N ii]/H α) index, but reaches ∼0.1 dex at the high-metallicity end for [N ii]/H α. (2) This result is based on the ∼kpc MaNGA resolution, so the real effect of the DIG is likely greater. (3) We revisit the mass–metallicity–star formation rate (SFR) relation by correcting for the DIG contribution in both abundances and SFR. The effect of DIG removal is more prominent at higher stellar masses. Using the [N ii]/Hα index, O/H increases with SFR at high stellar mass, contrary to previous claims.
The origin of parity changes in the solar cycle
Authors: Hazra Soumitra , Nandy Dibyendu
Published: September 2019

Although sunspots have been systematically observed on the Sun’s surface over the last four centuries, their magnetic properties have been revealed and documented only since the early 1900s. Sunspots typically appear in pairs of opposite magnetic polarities which have a systematic orientation. This polarity orientation is opposite across the equator – a trend that has persisted over the last century. Taken together with the configuration of the global poloidal field of the Sun – this phenomena is consistent with the dipolar parity state of an underlying magnetohydrodynamic dynamo. Although transient hemispheric asymmetry in sunspot emergence is observed, a global parity shift has never been observed. We simulate hemispheric asymmetry through introduction of random fluctuations in a computational dynamo model of the solar cycle and demonstrate that changes in parity are indeed possible in long-term simulations covering thousands of years. Quadrupolar modes are found to exist over significant fraction of the simulated time. In particular, we find that a parity shift in the underlying nature of the sunspot cycle is more likely to occur when sunspot activity dominates in any one hemisphere for a time which is significantly longer than the cycle period. We establish causal pathways connecting hemispheric asymmetry to parity flips mediated via a decoupling of the dynamo cycle period across the two solar hemispheres. Our findings indicate that the solar cycle may have resided in quadrupolar parity states in the past, and provides a possible pathway for predicting parity flips in the future.
Soft X-ray heating as a mechanism of optical continuum generation in solar-type star superflares
Authors: Nizamov Bulat A
Published: September 2019

Superflares on the solar-type stars observed by Kepler demonstrate the contrast in the optical continuum of the order 0.1–1 per cent. The mechanism of formation of this radiation is not firmly established. We consider a model where the stellar atmosphere is irradiated by the soft X-rays emitted from the flaring loop filled with the hot plasma. This radiation heats a large area beneath the loop. Subsequent cooling due to h− and hydrogen free–bound emission can contribute to the observed enhanced continuum. We solve the equations of radiative transfer, statistical equilibrium, ionization balance, and radiative equilibrium in the model atmosphere illuminated by the soft X-rays; compute the temperature and the electron density in the atmosphere; and find the emergent radiation. We found that a flare loop of the length ∼1010 cm and plasma density 1012 cm−3 at the temperature T = 20 MK can provide the contrast in the Kepler bandpass of 0.1 and 0.8 per cent if the heated region covers ∼1 and 10 per cent of the visible stellar surface, respectively. The required emission measure is of the order of 1055 cm−3.
Magnetic field, activity, and companions of V410 Tau
Authors: Yu L , Donati J-F , Grankin K , Collier Cameron A , Moutou C , Hussain G , Baruteau C , Jouve L , MaTYSSE collaboration the
Published: September 2019

We report the analysis, conducted as part of the MaTYSSE programme, of a spectropolarimetric monitoring of the ∼0.8 Myr, ∼1.4 M⊙ disc-less weak-line T Tauri star V410 Tau with the ESPaDOnS instrument at the Canada–France–Hawaii Telescope and NARVAL at the Télescope Bernard Lyot, between 2008 and 2016. With Zeeman-Doppler Imaging, we reconstruct the surface brightness and magnetic field of V410 Tau, and show that the star is heavily spotted and possesses a ∼550 G relatively toroidal magnetic field. We find that V410 Tau features a weak level of surface differential rotation between the equator and pole ∼5 times weaker than the solar differential rotation. The spectropolarimetric data exhibit intrinsic variability, beyond differential rotation, which points towards a dynamo-generated field rather than a fossil field. Long-term variations in the photometric data suggest that spots appear at increasing latitudes over the span of our data set, implying that, if V410 Tau has a magnetic cycle, it would have a period of more than 8 yr. Having derived raw radial velocities (RVs) from our spectra, we filter out the stellar activity jitter, modelled either from our Doppler maps or using Gaussian process regression. Thus filtered, our RVs exclude the presence of a hot Jupiter-mass companion below ∼0.1 au, which is suggestive that hot Jupiter formation may be inhibited by the early depletion of the circumstellar disc, which for V410 Tau may have been caused by the close (few tens of au) M dwarf stellar companion.
Gas accretion as fuel for residual star formation in Galaxy Zoo elliptical galaxies
Authors: Davis Timothy A , Young Lisa M
Published: September 2019

In this letter we construct a large sample of early-type galaxies (ETGs) with measured gas-phase metallicities from the Sloan Digital Sky Survey and Galaxy Zoo in order to investigate the origin of the gas that fuels their residual star formation. We use this sample to show that star-forming elliptical galaxies have a substantially different gas-phase metallicity distribution from spiral galaxies, with ≈7.4 per cent having a very low gas-phase metallicity for their mass. These systems typically have fewer metals in the gas phase than they do in their stellar photospheres, which strongly suggests that the material fuelling their recent star formation was accreted from an external source. We use a chemical evolution model to show that the enrichment time-scale for low-metallicity gas is very short, and thus that cosmological accretion and minor mergers are likely to supply the gas in ≳ 37 per cent of star-forming ETGs, in good agreement with estimates derived from other independent techniques.
METTL15 introduces N4-methylcytidine into human mitochondrial 12S rRNA and is required for mitoribosome biogenesis
Authors: Haute Lindsey Van , Hendrick Alan G , D’Souza Aaron R , Powell Christopher A , Rebelo-Guiomar Pedro , Harbour Michael E , Ding Shujing , Fearnley Ian M , Andrews Byron , Minczuk Michal
Published: September 2019

Post-transcriptional RNA modifications, the epitranscriptome, play important roles in modulating the functions of RNA species. Modifications of rRNA are key for ribosome production and function. Identification and characterization of enzymes involved in epitranscriptome shaping is instrumental for the elucidation of the functional roles of specific RNA modifications. Ten modified sites have been thus far identified in the mammalian mitochondrial rRNA. Enzymes responsible for two of these modifications have not been characterized. Here, we identify METTL15, show that it is the main N4-methylcytidine (m4C) methyltransferase in human cells and demonstrate that it is responsible for the methylation of position C839 in mitochondrial 12S rRNA. We show that the lack of METTL15 results in a reduction of the mitochondrial de novo protein synthesis and decreased steady-state levels of protein components of the oxidative phosphorylation system. Without functional METTL15, the assembly of the mitochondrial ribosome is decreased, with the late assembly components being unable to be incorporated efficiently into the small subunit. We speculate that m4C839 is involved in the stabilization of 12S rRNA folding, therefore facilitating the assembly of the mitochondrial small ribosomal subunits. Taken together our data show that METTL15 is a novel protein necessary for efficient translation in human mitochondria.
The human Shu complex functions with PDS5B and SPIDR to promote homologous recombination
Authors: Martino Julieta , Brunette Gregory J , Barroso-González Jonathan , Moiseeva Tatiana N , Smith Chelsea M , Bakkenist Christopher J , O’Sullivan Roderick J , Bernstein Kara A
Published: September 2019

RAD51 plays a central role in homologous recombination during double-strand break repair and in replication fork dynamics. Misregulation of RAD51 is associated with genetic instability and cancer. RAD51 is regulated by many accessory proteins including the highly conserved Shu complex. Here, we report the function of the human Shu complex during replication to regulate RAD51 recruitment to DNA repair foci and, secondly, during replication fork restart following replication fork stalling. Deletion of the Shu complex members, SWS1 and SWSAP1, using CRISPR/Cas9, renders cells specifically sensitive to the replication fork stalling and collapse caused by methyl methanesulfonate and mitomycin C exposure, a delayed and reduced RAD51 response, and fewer sister chromatid exchanges. Our additional analysis identified SPIDR and PDS5B as novel Shu complex interacting partners and genetically function in the same pathway upon DNA damage. Collectively, our study uncovers a protein complex, which consists of SWS1, SWSAP1, SPIDR and PDS5B, involved in DNA repair and provides insight into Shu complex function and composition.
HIF-transcribed p53 chaperones HIF-1α
Authors: Madan Esha , Parker Taylor M , Pelham Christopher J , Palma Antonio M , Peixoto Maria L , Nagane Masaki , Chandaria Aliya , Tomás Ana R , Canas-Marques Rita , Henriques Vanessa , Galzerano Antonio , Cabral-Teixeira Joaquim , Selvendiran Karuppaiyah , Kuppusamy Periannan , Carvalho Carlos , Beltran Antonio , Moreno Eduardo , Pati Uttam K , Gogna Rajan
Published: September 2019

Chronic hypoxia is associated with a variety of physiological conditions such as rheumatoid arthritis, ischemia/reperfusion injury, stroke, diabetic vasculopathy, epilepsy and cancer. At the molecular level, hypoxia manifests its effects via activation of HIF-dependent transcription. On the other hand, an important transcription factor p53, which controls a myriad of biological functions, is rendered transcriptionally inactive under hypoxic conditions. p53 and HIF-1α are known to share a mysterious relationship and play an ambiguous role in the regulation of hypoxia-induced cellular changes. Here we demonstrate a novel pathway where HIF-1α transcriptionally upregulates both WT and MT p53 by binding to five response elements in p53 promoter. In hypoxic cells, this HIF-1α-induced p53 is transcriptionally inefficient but is abundantly available for protein-protein interactions. Further, both WT and MT p53 proteins bind and chaperone HIF-1α to stabilize its binding at its downstream DNA response elements. This p53-induced chaperoning of HIF-1α increases synthesis of HIF-regulated genes and thus the efficiency of hypoxia-induced molecular changes. This basic biology finding has important implications not only in the design of anti-cancer strategies but also for other physiological conditions where hypoxia results in disease manifestation.
Dynamical ensemble of the active state and transition state mimic for the RNA-cleaving 8–17 DNAzyme in solution
Authors: Ekesan Şölen , York Darrin M
Published: September 2019

We perform molecular dynamics simulations, based on recent crystallographic data, on the 8–17 DNAzyme at four states along the reaction pathway to determine the dynamical ensemble for the active state and transition state mimic in solution. A striking finding is the diverse roles played by Na+ and Pb2+ ions in the electrostatically strained active site that impact all four fundamental catalytic strategies, and share commonality with some features recently inferred for naturally occurring hammerhead and pistol ribozymes. The active site Pb2+ ion helps to stabilize in-line nucleophilic attack, provides direct electrostatic transition state stabilization, and facilitates leaving group departure. A conserved guanine residue is positioned to act as the general base, and is assisted by a bridging Na+ ion that tunes the pKa and facilitates in-line fitness. The present work provides insight into how DNA molecules are able to solve the RNA-cleavage problem, and establishes functional relationships between the mechanism of these engineered DNA enzymes with their naturally evolved RNA counterparts. This adds valuable information to our growing body of knowledge on general mechanisms of phosphoryl transfer reactions catalyzed by RNA, proteins and DNA.