bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanical analysis of lateral uplift of aluminum film scribed by grating
Authors: Lu Ji
Published: August 2020

During the diffraction grating scoring process, the stress change on the aluminum film greatly affects the groove morphology. In view of the current status of “trial and error” of grating scoring, in order to study the rule of lateral bulging of aluminum film in the process of grating scoring, this paper aims at the formation rule of groove topography during the process of grating scoring, which is affected by the change of the surface film material force. The slip line field theory and the speed upper limit field theory establish a simple model for the stress process of the material during the scoring process.
Cobalt and Nitrogen Co-Doped Electrospun Carbon Nanofibers as a Bifunctional Oxygen Electrocatalyst
Authors: Li T J , Wang H G
Published: August 2020

Nowadays, it is urgent to prepare a bifunctional electrocatalyst with effectively improve catalytic properties towards ORR and OER, replacing precious metals and commercial catalysts. Cobalt nitrogen co-doped carbon nanofibers (Co-N/CNFs) are successfully synthesized via solvothermal, pyrolysis of electrospun nanofibers containing cobalt phthalocyanine and melamine. The electrochemical characterization of Co-N/CNFs-800 is carried out using cyclic voltammetry, and Tafel studies compared with Pt/C and RuO2. The Co-N/CNFs-800 exhibits the higher ORR catalytic activity with half-wave potential (0.77 V) and the lower OER overpotential (370 mV). Furthermore, the activity parameter of Co-N/CNFs-800 (0.83 V) is much lower than that of Pt/C (0.95 V), and closer to RuO2 (0.82 V). This research opens an effective method to synthesize an excellent bifunctional electrocatalyst for ORR/OER.
On the best constant in the estimate related to 𝐻¹-𝐵𝑀𝑂 duality
Authors: Osękowski Adam
Published: August 2020

Let

I
⊂

R

I\subset \mathbb {R}

be an interval and let

f
f

,

φ
\varphi

be arbitrary elements of

H
1

(
I
)

H^1(I)

and

B
M
O
(
I
)

BMO(I)

, respectively, with

∫
I

φ
=
0

\int _I\varphi =0

. The paper contains the proof of the estimate
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="integral Underscript upper I Endscripts f phi less-than-or-equal-to StartRoot 2 EndRoot double-vertical-bar f double-vertical-bar Subscript upper H Sub Superscript 1 Subscript left-parenthesis upper I right-parenthesis Baseline double-vertical-bar phi double-vertical-bar Subscript upper B upper M upper O left-parenthesis upper I right-parenthesis Baseline comma">

∫
I

f
φ
≤

2

‖
f

‖

H
1

(
I
)

‖
φ

‖

B
M
O
(
I
)

,

\begin{equation*} \int _I f\varphi \leq \sqrt {2}\|f\|_{H^1(I)}\|\varphi \|_{BMO(I)}, \end{equation*}

and it is shown that

2

\sqrt {2}

cannot be replaced by a smaller universal constant. The argument rests on the existence of a special function enjoying appropriate size and concavity requirements.
The Euler-Jacobi formula and the planar quadratic-quartic polynomial differential systems
Authors: Llibre Jaume , Valls Claudia
Published: August 2020

The Euler-Jacobi formula provides an algebraic relation between the singular points of a polynomial vector field and their topological indices. Using this formula we obtain the configuration of the singular points together with their topological indices for the planar quadratic-quartic polynomial differential systems when these systems have eight finite singular points.
The algebra of recurrence relations for exceptional Laguerre and Jacobi polynomials
Authors: Durán Antonio
Published: August 2020

Exceptional Laguerre and Jacobi polynomials

p
n

(
x
)

p_n(x)

are bispectral, in the sense that as functions of the continuous variable

x
x

, they are eigenfunctions of a second order differential operator and as functions of the discrete variable

n
n

, they are eigenfunctions of a higher order difference operator (the one defined by any of the recurrence relations they satisfy). In this paper, under mild conditions on the sets of parameters, we characterize the algebra of difference operators associated to the higher order recurrence relations satisfied by the exceptional Laguerre and Jacobi polynomials.
Maximality and finiteness of type 1 subdiagonal algebras
Authors: Ji Guoxing
Published: August 2020

Let

A

\mathfrak A

be a type 1 subdiagonal algebra in a

σ
\sigma

-finite von Neumann algebra

M

\mathcal M

with respect to a faithful normal conditional expectation

Φ
\Phi

. We give necessary and sufficient conditions for which

A

\mathfrak A

is maximal among the

σ
\sigma

-weakly closed subalgebras of

M

\mathcal M

. In addition, we show that a type 1 subdiagonal algebra in a finite von Neumann algebra is automatically finite which gives a positive answer of Arveson’s finiteness problem in 1967 in type 1 case.
Counterexamples to the local-global principle for non-singular plane curves and a cubic analogue of Ankeny-Artin-Chowla-Mordell conjecture
Authors: Hirakawa Yoshinosuke , Shimizu Yosuke
Published: August 2020

In this article, we introduce a systematic and uniform construction of non-singular plane curves of odd degrees

n
≥
5

n \geq 5

which violate the local-global principle. Our construction works unconditionally for

n
n

divisible by

p

2

p^{2}

for some odd prime number

p
p

. Moreover, our construction also works for

n
n

divisible by some

p
≥
5

p \geq 5

which satisfies a conjecture on a

p
p

-adic property of the fundamental unit of

Q

(

p

1

/

3

)

\mathbb {Q}(p^{1/3})

and

Q

(
(
2
p

)

1

/

3

)

\mathbb {Q}((2p)^{1/3})

. This conjecture is a natural cubic analogue of the classical Ankeny-Artin-Chowla-Mordell conjecture for

Q

(

p

1

/

2

)

\mathbb {Q}(p^{1/2})

and easily verified numerically.
Density behaviour related to Lévy processes
Authors: Chaumont Loïc , Małecki Jacek
Published: August 2020

Let

p
t

(
x
)

p_t(x)

,

f
t

(
x
)

f_t(x)

and

q
t
∗

(
x
)

q_t^*(x)

be the densities at time

t
t

of a real Lévy process, its running supremum and the entrance law of the reflected excursions at the infimum. We provide relationships between the asymptotic behaviour of

p
t

(
x
)

p_t(x)

,

f
t

(
x
)

f_t(x)

and

q
t
∗

(
x
)

q_t^*(x)

, when

t
t

is small and

x
x

is large. Then for large

x
x

, these asymptotic behaviours are compared to this of the density of the Lévy measure. We show in particular that, under mild conditions, if

p
t

(
x
)

p_t(x)

is comparable to

t
ν
(
x
)

t\nu (x)

, as

t
→
0

t\rightarrow 0

and

x
→
∞

x\rightarrow \infty

, then so is

f
t

(
x
)

f_t(x)

.
Ordinary families of Klingen Eisenstein series on symplectic groups
Authors: Liu Zheng
Published: August 2020

We construct

(
n
+
1
)

(n+1)

-variable Hida families of Klingen Eisenstein series on

Sp
⁡
(
2
n
+
2
)

\operatorname {Sp}(2n+2)

for

n
n

-variable Hida families on

Sp
⁡
(
2
n
)

\operatorname {Sp}(2n)

, and relate their images under the Siegel operator to

p
p

-adic

L
L

-functions. We also carry out some preliminary calculations of the non-degenerate Fourier coefficients of the constructed Klingen Eisenstein families.
Retinal Arteriolar Occlusions and Exudative Retinal Detachments in Malignant Hypertension: More Than Meets the Eye
Authors: de Nattes Tristan , Saad Rana , Buob David , Verney Charles , Doreille Alice , Luque Yosu , Mesnard Laurent , Pâques Michel , Rafat Cédric
Published: August 2020

BACKGROUND

Malignant hypertension is macrovascular and microvascular endothelial injury responsible for multiple organ damage. Considering the anatomical and functional homologies between the posterior pole of the eye and the kidney, ophthalmological explorations may inform clinicians on the mechanisms underpinning concurrent kidney injury in this condition. More specifically, we investigated whether the wall-to-lumen ratio (WLR) of retinal arterioles measured by adaptive optics ophthalmoscopy could be correlated to WLR of kidney arterioles as determined by pathology. We sought to estimate the incidence of retinal arteriole occlusion a supposedly uncommon complication of malignant hypertension.

METHODS

All patients hospitalized in our renal Intensive Care Unit for malignant hypertension between 2016 and 2019 were referred to ophthalmological examinations.

RESULTS

Twenty-seven patients were included. Median retinal WLR was 0.39 [0.31–0.47] and was correlated with initial systolic (r = 0.56, P = 0.003) and mean blood pressure (r = 0.46, P = 0.02) upon admission. The retinal WLR was not correlated to renal pathological findings, as assessed by juxtaglomerular WLR (r = 0.38, P = 0.2), ratio of glomerulosclerosis (r = −0.39, P = 0.2), or tubulointerstitial fibrosis (r = −0.45, P = 0.08). Retinal WLR was not associated with neurological or cardiovascular end-organ damage. Branch retinal artery occlusion was detected in 18.5% of patients and exudative retinal detachment (ERD) in 29.6% of patients, without any significant correlation with canonical signs of retinal hypertension including optic disc swelling.

CONCLUSIONS

In the setting of malignant hypertension, we failed to demonstrate a significant relationship between WLR and other meaningful end-organ injuries. However, branch retinal artery occlusion and ERD may have been hitherto underestimated.
Cluster-randomized Trial of Adjuvanted Versus Nonadjuvanted Trivalent Influenza Vaccine in 823 US Nursing Homes
Authors: McConeghy Kevin W , Davidson H Edward , Canaday David H , Han Lisa , Saade Elie , Mor Vince , Gravenstein Stefan
Published: August 2020

Background

Influenza leads in preventable infection-related hospitalization in nursing home (NH) residents. The adjuvanted trivalent influenza vaccine (aTIV) is more immunogenic than similarly dosed nonadjuvanted trivalent influenza vaccine (TIV), and observational studies suggest aTIV better prevents hospitalizations in older adults. We prospectively tested this in an NH setting.

Methods

NHs with ≥50 long-stay residents aged ≥65 years were randomized to offer aTIV or TIV for residents for the 2016–2017 influenza season. Using intent-to-treat resident-level analysis with Cox proportional hazards regression models adjusted for clustering by facility and a priori baseline covariates (eg, age, heart failure, and facility-level characteristics), we assessed relative aTIV:TIV effectiveness for hospitalization (ie, all-cause, respiratory, and pneumonia and influenza [P&I]).

Results

We randomized 823 NHs, housing 50 012 eligible residents, to aTIV or TIV. Residents were similar between groups by age (mean, ~79 years), heart failure, lung disease, and influenza and pneumococcal vaccine uptake, except aTIV homes housed fewer Black residents (14.5 vs 18.9%). Staff vaccine uptake was similar (~55%). P&I and all-cause resident hospitalization rates were lower (adjusted HR [aHR], .80 [95% CI, .66–.98; P = .03] and .94 [.89–.99; P = .02], respectively) for aTIV versus TIV, while the respiratory hospitalization rate was similar, in a season where vaccine effectiveness was considered poor.

Conclusions

aTIV was more effective than TIV in preventing all-cause and P&I hospitalization from NHs during an A/H3N2-predominant season when TIV was relatively ineffective.

Clinical Trials Registration

NCT02882100.
Tap Water Avoidance Decreases Rates of Hospital-onset Pulmonary Nontuberculous Mycobacteria
Authors: Baker Arthur W , Stout Jason E , Anderson Deverick J , Sexton Daniel J , Smith Becky , Moehring Rebekah W , Huslage Kirk , Hostler Christopher J , Lewis Sarah S
Published: August 2020

We analyzed the impact of a hospital tap water avoidance protocol on respiratory isolation of nontuberculous mycobacteria (NTM). After protocol implementation, hospital-onset episodes of respiratory NTM isolation on high-risk units decreased from 41.0 to 9.9 episodes per 10 000 patient-days (incidence rate ratio, 0.24; 95% confidence interval, .17–.34; P < .0001).
Cryptococcal Antigen in Serum and Cerebrospinal Fluid for Detecting Cryptococcal Meningitis in Adults Living With Human Immunodeficiency Virus: Systematic Review and Meta-Analysis of Diagnostic Test Accuracy Studies
Authors: Temfack Elvis , Rim Jean Joel Bigna , Spijker Rene , Loyse Angela , Chiller Tom , Pappas Peter G , Perfect John , Sorell Tania C , Harrison Thomas S , Cohen Jérémie F , Lortholary Olivier
Published: August 2020

Cryptococcal antigen (CrAg) detection could direct the timely initiation of antifungal therapy. We searched MEDLINE and Embase for studies where CrAg detection in serum/cerebrospinal fluid (CSF) and CSF fungal culture were done on adults living with human immunodeficiency virus (HIV) who had suspected cryptococcal meningitis (CM). With Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2), we evaluated the risk of bias in 11 included studies with 3600 participants, and used a random-effects meta-analysis to obtain summary sensitivity and specificity of serum and CSF CrAg, as well as agreement between CSF CrAg and CSF culture. Summary sensitivity and specificity of serum CrAg were 99.7% (97.4–100) and 94.1% (88.3–98.1), respectively, and summary sensitivity and specificity of CSF CrAg were 98.8% (96.2–99.6) and 99.3% (96.7–99.9), respectively. Agreement between CSF CrAg and CSF culture was 98% (97–99). In adults living with HIV who have CM symptoms, serum CrAg negativity may rule out CM, while positivity should prompt induction antifungal therapy if lumbar puncture is not feasible. In a first episode of CM, CSF CrAg positivity is diagnostic.
Randomized comparison of oesophageal protection with a temperature control device: results of the IMPACT study
Authors: Leung Lisa W M , Bajpai Abhay , Zuberi Zia , Li Anthony , Norman Mark , Kaba Riyaz A , Akhtar Zaki , Evranos Banu , Gonna Hanney , Harding Idris , Sohal Manav , Al-Subaie Nawaf , Louis-Auguste John , Hayat Jamal , Gallagher Mark M
Published: August 2020

Aims 

Thermal injury to the oesophagus is an important cause of life-threatening complication after ablation for atrial fibrillation (AF). Thermal protection of the oesophageal lumen by infusing cold liquid reduces thermal injury to a limited extent. We tested the ability of a more powerful method of oesophageal temperature control to reduce the incidence of thermal injury.

Methods and results 

A single-centre, prospective, double-blinded randomized trial was used to investigate the ability of the ensoETM device to protect the oesophagus from thermal injury. This device was compared in a 1:1 randomization with a control group of standard practice utilizing a single-point temperature probe. In the protected group, the device maintained the luminal temperature at 4°C during radiofrequency (RF) ablation for AF under general anaesthesia. Endoscopic examination was performed at 7 days post-ablation and oesophageal injury was scored. The patient and the endoscopist were blinded to the randomization. We recruited 188 patients, of whom 120 underwent endoscopy. Thermal injury to the mucosa was significantly more common in the control group than in those receiving oesophageal protection (12/60 vs. 2/60; P = 0.008), with a trend toward reduction in gastroparesis (6/60 vs. 2/60, P = 0.27). There was no difference between groups in the duration of RF or in the force applied (P value range= 0.2–0.9). Procedure duration and fluoroscopy duration were similar (P = 0.97, P = 0.91, respectively).

Conclusion 

Thermal protection of the oesophagus significantly reduces ablation-related thermal injury compared with standard care. This method of oesophageal protection is safe and does not compromise the efficacy or efficiency of the ablation procedure.
Bacterial community dynamics across developmental stages of fungal fruiting bodies
Authors: Gohar Daniyal , Pent Mari , Põldmaa Kadri , Bahram Mohammad
Published: August 2020

Increasing evidence suggest that bacteria form diverse communities in various eukaryotic hosts, including fungi. However, little is known about their succession and the functional potential at different host development stages. Here we examined the effect of fruiting body parts and developmental stages on the structure and potential function of fungus-associated bacterial communities. Using high-throughput sequencing, we characterized bacterial communities and their associated potential functions in fruiting bodies from ten genera belonging to four major mushroom-forming orders and three different developmental stages of a model host species Cantharellus cibarius. Our results demonstrate that bacterial community structure differs between internal and external parts of the fruiting body but not between inner tissues. The structure of the bacterial communities showed significant variation across fruiting body developmental stages. We provide evidence that certain functional groups, such as those related to nitrogen fixation, persist in fruiting bodies during the maturation, but are replaced by putative parasites/pathogens afterwards. These data suggest that bacterial communities inhabiting fungal fruiting bodies may play important roles in their growth and development.
Tissue-based Gene Expression as Potential Biomarkers for IBD Course
Authors: Haberman Yael
Published: August 2020

Inflammatory bowel diseases (IBDs) are highly heterogeneous in disease phenotype, behavior, and response to therapy. Diagnostic and therapeutic decisions in IBD are based primarily on clinical and endoscopic severity and histopathologic analysis of intestinal biopsies. With this approach, however, only a minority of patients experience durable remission. This may be due to substantial heterogeneity in disease pathogenicity that is not accounted for by current classification systems. Patients can present with similar clinical and endoscopic severity and receive similar therapy but show divergent response ranging from mucosal/transmural healing to nonresponse. Using mucosal biopsy samples that are already obtained as part of the clinical practice to support the diagnosis and state-of-the-art high throughput sequencing approaches can detect the widest range in host gene expression in the actual lining of the affected gut. These analyses can better dissect disease heterogeneity and guide potential treatment response. Here we review studies that use gut tissue–based gene expression profiles to predict disease outcome in IBD.
The Role of the Private Sector in Supporting Malaria Control in Resource Development Settings
Authors: Jones Robert T , Tusting Lucy S , Smith Hugh M P , Segbaya Sylvester , Macdonald Michael B , Bangs Michael J , Logan James G
Published: August 2020

Industrial operations of the private sector, such as extraction, agriculture, and construction, can bring large numbers of people into new settlement areas and cause environmental change that promotes the transmission of vector-borne diseases. Industry-related workers and communities unduly exposed to infection risk typically lack the knowledge and means to protect themselves. However, there is a strong business rationale for protecting local resident employees through integrated vector control programs, as well as an ethical responsibility to care for these individuals and the affected communities. We discuss the role and challenges of the private sector in developing malaria control programs, which can include extensive collaborations with the public sector that go on to form the basis of national vector control programs or more broadly support local healthcare systems.
Opioid Use Disorder and Associated Infectious Disease: The Role of the Laboratory in Addressing Health Disparities
Authors: Farnsworth Christopher W , Lloyd Matthew , Jean Sophonie
Published: August 2020

Background

Opioid use disorder, defined as a pattern of problematic opioid use leading to clinically significant impairment, has resulted in considerable morbidity and mortality throughout the world. This is due, at least in part, to the marginalized status of patients with opioid use disorder, limiting their access to appropriate laboratory testing, diagnosis, and treatment. Infections have long been associated with illicit drug use and contribute considerably to morbidity and mortality. However, barriers to testing and negative stigmas associated with opioid use disorder present unique challenges to infectious disease testing in this patient population.

Content

This review addresses the associations between opioid use disorder and infectious organisms, highlighting the health disparities encountered by patients with opioid use disorder, and the important role of laboratory testing for diagnosing and managing these patients.

Infections are among the most frequent and adverse complications among patients with opioid use disorder. As a result of health disparities and systemic biases, patients that misuse opioids are less likely to receive laboratory testing and treatment. However, laboratories play a crucial in identifying patients that use drugs illicitly and infections associated with illicit drug use.
Survival in patients with glioblastoma at a first progression does not correlate with isocitrate dehydrogenase (IDH)1 gene mutation status
Authors: Tabei Yusuke , Kobayashi Keiichi , Saito Kuniaki , Shimizu Saki , Suzuki Kaori , Sasaki Nobuyoshi , Shiokawa Yoshiaki , Nagane Motoo
Published: August 2020

Backgrounds

Mutations in the isocitrate dehydrogenase (IDH)1 gene are favourable prognostic factors in newly diagnosed diffuse gliomas, whereas it remains controversial in the recurrent glioblastoma setting.

Methods

A total of 171 patients with newly diagnosed glioblastoma, either ‘primary’ glioblastoma or ‘secondary’ glioblastoma, treated at Kyorin University Hospital or Japanese Red Cross Medical Center from 2000 to 2015 were included. Patients with confirmed IDH1 status and O6-methylguanine-DNA methyltransferase promoter methylation status were retrospectively analysed for overall survival from the initial diagnosis (n = 147) and after the first progression (n = 122).

Results

IDH1 mutation but not IDH2 was noted in 19 of 147 patients with glioblastoma (12.9%). In patients with ‘primary’ glioblastoma (n = 136), median overall survival after the first progression was 13.5 and 10.5 months for mutant IDH1 and wild-type IDH1 glioblastoma, respectively (P = 0.747). Multivariate analysis revealed O6-methylguanine-DNA methyltransferase promoter methylation, and Karnofsky Performance status 60 or higher, were independent prognostic factors for better overall survival after the first progression. When ‘primary’ glioblastoma and ‘secondary’ glioblastoma were combined, median overall survival from the first progression was not significantly different between the mutant IDH1 group (10.1 months) and wild-type IDH1 group (10.5 months) (P = 0.559), whereas median overall survival from the initial diagnosis was significantly different (47.5 months vs.18.3 months, respectively; P = 0.035).

Conclusions

These results suggest that IDH1 mutation may not be a prognostic factor for survival at the first progression of patients with ‘primary’ glioblastoma and pretreated ‘secondary’ glioblastoma, and further warrant investigation in prospective studies.
Incidence Trends and Burden of Human Papillomavirus-Associated Cancers Among Women in the United States, 2001-2017
Authors: Deshmukh Ashish A , Suk Ryan , Shiels Meredith S , Damgacioglu Haluk , Lin Yueh-Yun , Stier Elizabeth A , Nyitray Alan G , Chiao Elizabeth Y , Nemutlu Gizem S , Chhatwal Jagpreet , Schmeler Kathleen , Sigel Keith , Sonawane Kalyani
Published: August 2020

Human papillomavirus (HPV)-associated anal and oropharyngeal cancer incidence has increased in recent years among US women. However, trends in incidence and burden (annual number of cases) of noncervical HPV-associated cancers relative to cervical cancer remain unclear. Using the 2001-2017 US cancer statistics dataset, we evaluated contemporary incidence trends and burden (annual number of cases) of HPV-associated cancers among women by anatomic site, race or ethnicity, and age. Overall, cervical cancer incidence plateaued among White women but continued to decline among Black and Hispanic women. Anal cancer incidence surpassed cervical cancer incidence among White women aged 65-74 years of age (8.6 and 8.2 per 100 000 in 2015) and 75 years or older (6.2 and 6.0 per 100 000 in 2014). The noncervical cancer burden (n  =  11 871) surpassed the cervical cancer burden (n  =  11 527) in 2013. Development of efficacious screening strategies for noncervical cancers and continued improvement in cervical cancer prevention are needed to combat HPV-associated cancers among women.
Illness-Related Parenting Stress and Maladjustment in Congenital Heart Disease: Mindfulness as a Moderator
Authors: Bishop Meredith , Cohen Lindsey L , Robbertz Abigail S
Published: August 2020

Objective

Congenital heart disease (CHD) is characterized by structural defects to the heart or the coronary blood vessels and often requires surgical repair. Raising an infant or toddler with CHD can be challenging and lead to high parenting stress and maladjustment. The parenting literature suggests that mindfulness may buffer parenting stress. The purpose of this study was to examine whether mindfulness might moderate the relationship between illness-related parenting stress and maladjustment in parents of infants and toddlers with CHD.

Methods

Parents of infants and toddlers with CHD attending an outpatient clinic provided background information and completed measures of illness-related parenting stress, mindfulness, and maladjustment.

Results

Results indicated that illness-related parenting stress was associated with maladjustment, and mindfulness moderated this relationship. Specifically, illness-related parenting stress was related to maladjustment at low and average levels of mindfulness; at high mindfulness, there was no association between illness-related parenting stress and maladjustment.

Conclusions

Consistent with the broader literatures, our sample of parents of infants and toddlers with CHD reported high illness-related parenting stress and maladjustment. Building on other studies demonstrating the benefits of mindful parenting, our results suggest that engaging in mindfulness might thwart the association between illness-related parenting stress and maladjustment in parents of infants and toddlers with CHD.
Convective differential rotation in stars and planets – I. Theory
Authors: Jermyn Adam S , Chitre Shashikumar M , Lesaffre Pierre , Tout Christopher A
Published: August 2020

We derive the scaling of differential rotation in both slowly and rapidly rotating convection zones using order of magnitude methods. Our calculations apply across stars and fluid planets and all rotation rates, as well as to both magnetized and purely hydrodynamic systems. We find shear |R∇Ω| of order the angular frequency Ω for slowly rotating systems with Ω ≪ |N|, where N is the Brünt–Väisälä frequency, and find that it declines as a power law in Ω for rapidly rotating systems with Ω ≫ |N|. We further calculate the meridional circulation rate and baroclinicity and examine the magnetic field strength in the rapidly rotating limit. Our results are in general agreement with simulations and observations and we perform a detailed comparison with those in a companion paper.
The absolute proper motions of the Arches and Quintuplet clusters
Authors: Libralato Mattia , Fardal Mark , Lennon Daniel , van der Marel Roeland P , Bellini Andrea
Published: August 2020

Arches and Quintuplet are two young, massive clusters projected near the Galactic Centre. To date, studies focused on understanding their origin have been based on proper motions (PMs) derived in the clusters’ reference frames and required some assumptions about their 3D motion. In this paper, we combine public PM catalogues of these clusters with the Gaia DR2 catalogue and, for the first time, transform the relative PMs of the Arches and Quintuplet clusters on to an absolute reference system. We find that the absolute PM of the Arches is (μαcos δ, μδ) = (−1.45 ± 0.23, −2.68 ± 0.14) mas yr−1 and that of the Quintuplet is (μαcos δ, μδ) = (−1.19 ± 0.09, −2.66 ± 0.18) mas yr−1. These values suggest that these systems are moving almost parallel to the Galactic plane. A measurement of the clusters’ distances is still required to meaningfully constrain the clusters’ orbits and shed light on the origin of the Arches and Quintuplet.
Cosmic flows in the nearby Universe: new peculiar velocities from SNe and cosmological constraints
Authors: Boruah Supranta S , Hudson Michael J , Lavaux Guilhem
Published: August 2020

The peculiar velocity field offers a unique way to probe dark matter density field on large scales at low redshifts. In this work, we have compiled a new sample of 465 peculiar velocities from low redshift ($z$ < 0.067) Type Ia supernovae. We compare the reconstructed velocity field derived from the 2M++ galaxy redshift compilation to the supernovae, the SFI++ and the 2MTF Tully–Fisher distance catalogues. We used a forward method to jointly infer the distances and the velocities of distance indicators by comparing the observations to the reconstruction. Comparison of the reconstructed peculiar velocity fields to observations allows us to infer the cosmological parameter combination fσ8, and the bulk flow velocity arising from outside the survey volume. The residual bulk flow arising from outside the 2M++ volume is inferred to be $171^{+11}_{-11}$ km s−1 in the direction l = 301° ± 4° and b = 0° ± 3°. We obtain fσ8 = 0.400 ± 0.017, equivalent to S8 ≈ σ8(Ωm/0.3)0.55 = 0.776 ± 0.033, which corresponds to an approximately $4{{\ \rm per\ cent}}\,$ statistical uncertainty on the value of fσ8. Our inferred value is consistent with other low redshift results in the literature.
Galaxy properties in the cosmic web of EAGLE simulation
Authors: Xu Wenxiao , Guo Qi , Zheng Haonan , Gao Liang , Lacey Cedric , Gu Qing , Liao Shihong , Shao Shi , Mao Tianxiang , Zhang Tianchi , Chen Xuelei
Published: August 2020

We investigate the dependence of the galaxy properties on cosmic web environments using the most up-to-date hydrodynamic simulation: Evolution and Assembly of Galaxies and their Environments (EAGLE). The baryon fractions in haloes and the amplitudes of the galaxy luminosity function decrease going from knots to filaments to sheets to voids. Interestingly, the value of L* varies dramatically in different cosmic web environments. At z = 0, we find a characteristic halo mass of $10^{12}\, {\rm h}^{-1}\rm M_{\odot }$, below which the stellar-to-halo mass ratio is higher in knots, while above which it reverses. This particular halo mass corresponds to a characteristic stellar mass of $1.8\times 10^{10} \,{\rm h}^{-1}\rm M_{\odot }$. Below the characteristic stellar mass, central galaxies have redder colours, lower sSFRs, and higher metallicities in knots than those in filaments, sheets and voids, while above this characteristic stellar mass, the cosmic web environmental dependences either reverse or vanish. Such dependences can be attributed to the fact that the active galaxy fraction decreases along voids, sheets, filaments, and knots. The cosmic web dependences get weaker towards higher redshifts for most of the explored galaxy properties and scaling relations, except for the gas metallicity versus stellar mass relation.
Exoplanet validation with machine learning: 50 new validated Kepler planets
Authors: Armstrong David J , Gamper Jevgenij , Damoulas Theodoros
Published: August 2020

Over 30 per cent of the $\sim$4000 known exoplanets to date have been discovered using ‘validation’, where the statistical likelihood of a transit arising from a false positive (FP), non-planetary scenario is calculated. For the large majority of these validated planets calculations were performed using the vespa algorithm. Regardless of the strengths and weaknesses of vespa, it is highly desirable for the catalogue of known planets not to be dependent on a single method. We demonstrate the use of machine learning algorithms, specifically a Gaussian process classifier (GPC) reinforced by other models, to perform probabilistic planet validation incorporating prior probabilities for possible FP scenarios. The GPC can attain a mean log-loss per sample of 0.54 when separating confirmed planets from FPs in the Kepler Threshold-Crossing Event (TCE) catalogue. Our models can validate thousands of unseen candidates in seconds once applicable vetting metrics are calculated, and can be adapted to work with the active Transiting Exoplanet Survey Satellite (TESS) mission, where the large number of observed targets necessitate the use of automated algorithms. We discuss the limitations and caveats of this methodology, and after accounting for possible failure modes newly validate 50 Kepler candidates as planets, sanity checking the validations by confirming them with vespa using up to date stellar information. Concerning discrepancies with vespa arise for many other candidates, which typically resolve in favour of our models. Given such issues, we caution against using single-method planet validation with either method until the discrepancies are fully understood.
Swift unveils the orbital period of IGR J18214-1318
Authors: Cusumano G , D’Aì A , Segreto A , La Parola V , Del Santo M
Published: August 2020

We analysed 13 yr of the Neil Gehrels Swift Observatory survey data collected on the high-mass X-ray binary IGR J18214-1318. Performing the timing analysis, we detected a periodic signal of 5.42 d. From the companion star characteristics, we derived an average orbital separation of $\sim 41 \rm R_{\odot }\simeq 2 R_{\star }$. The spectral type of the companion star (O9) and the tight orbital separation suggest that IGR J18214-1318 is a wind-accreting source with eccentricity lower than 0.17. The intensity profile folded at the orbital period shows a deep minimum compatible with an eclipse of the source by the companion star. In addition, we report on the broad-band 0.6–100 keV spectrum using data from XMM–Newton, NuSTAR, and Swift, applying self-consistent physical models. We find that the spectrum is well fitted either by a pure thermal Comptonization component, or, assuming that the source is a neutron star accreting above the critical regime, by a combined thermal and bulk motion Comptonization model. In both cases, the presence of a local neutral absorption (possibly related to the thick wind of the companion star) is required.
Testing an indirect method for identifying galaxies with high levels of Lyman continuum leakage
Authors: Yamanaka Satoshi , Inoue Akio K , Yamada Toru , Zackrisson Erik , Iwata Ikuru , Micheva Genoveva , Mawatari Ken , Hashimoto Takuya , Kubo Mariko
Published: August 2020

Using a sample of galaxies at z ≈ 3 with detected Lyman Continuum (LyC) leakage in the SSA22 field, we attempt to verify a proposed indirect method for identifying cases with high LyC escape fraction fesc based on measurements of the H β equivalent width (EW) and the β slope of the UV continuum. To this end, we present Keck/MOSFIRE H β emission line flux measurements of LyC galaxies (LCGs) at spectroscopic redshifts zspec ∼ 3.3, Lyman break galaxies (LBGs) at photometric redshifts zphot = 2.7–3.7, and Ly α emitters at zphot = 3.1. We also reconfirm the spectroscopic redshifts and measure the H β emission-line fluxes from two LCGs and six LBGs. For the LCG in our sample with the most extreme fesc, as revealed by the direct detection of LyC photons, we find that the EW(H β)–β method gives a broadly consistent estimate for fesc, although the error bars remain very large. We also discuss how a combination of fesc measurements based on direct and indirect methods can shed light on the LyC escape mechanism and the anisotropy of the leakage.
An eclipsing M-dwarf close to the hydrogen burning limit from NGTS
Authors: Acton Jack S , Goad Michael R , Casewell Sarah L , Vines Jose I , Burleigh Matthew R , Eigmüller Philipp , Nielsen Louise D , Gänsicke Boris T , Bayliss Daniel , Bouchy François , Bryant Edward M , Gill Samuel , Gillen Edward , Günther Maximilian N , Jenkins James S , McCormac James , Moyano Maximiliano , Raynard Liam R , Tilbrook Rosanna H , Udry Stéphane , Watson Christopher A , West Richard G , Wheatley Peter J
Published: August 2020

We present the discovery of NGTS J0930−18, an extreme mass ratio eclipsing M-dwarf binary system with an early M-dwarf primary and a late M-dwarf secondary close to the hydrogen burning limit. Global modelling of photometry and radial velocities reveals that the secondary component (NGTS J0930−18 B) has a mass of M* = $0.0818 ^{+0.0040}_{-0.0015}$ M⊙ and radius of R* = $0.1059 ^{+0.0023}_{-0.0021}$ R⊙, making it one of the lowest mass stars with direct mass and radius measurements. With a mass ratio of q = $0.1407 ^{+0.0065}_{-0.017}$, NGTS J0930−18 has the lowest mass ratio of any known eclipsing M-dwarf binary system, posing interesting questions for binary star formation and evolution models. The mass and radius of NGTS J0930−18 B is broadly consistent with stellar evolutionary models. NGTS J0930−18 B lies in the sparsely populated mass radius parameter space close to the substellar boundary. Precise measurements of masses and radii from single lined eclipsing binary systems of this type are vital for constraining the uncertainty in the mass–radius relationship – of importance due to the growing number of terrestrial planets being discovered around low-mass stars.
Gas trapping of hot dust around main-sequence stars
Authors: Pearce Tim D , Krivov Alexander V , Booth Mark
Published: August 2020

In 2006, Vega was discovered to display excess near-infrared (NIR) emission. Surveys now detect this phenomenon for one fifth of main-sequence stars, across various spectral types and ages. The excesses are interpreted as populations of small, hot dust grains very close to their stars, which must originate from comets or asteroids. However, the presence of such grains in copious amounts is mysterious, since they should rapidly sublimate or be blown out of the system. Here, we investigate a potential mechanism to generate excesses: dust migrating inwards under radiation forces sublimates near the star, releasing modest quantities of gas that then traps subsequent grains. This mechanism requires neither specialized system architectures nor high dust supply rates, and could operate across diverse stellar types and ages. The model naturally reproduces many features of inferred dust populations, in particular their location, preference for small grains, steep size distribution, and dust location scaling with stellar luminosity. For Sun-like stars, the mechanism can produce ${2.2 \; \mu {\rm m}}$ excesses that are an order of magnitude larger than those at ${8.5 \; \mu {\rm m}}$, as required by observations. However, for A-type stars the simulated NIR excesses were only twice those in the mid-infrared; grains would have to be 5–10 times smaller than those trapped in our model to be able to explain observed NIR excesses around A stars. Further progress with any hot dust explanation for A stars requires a means for grains to become very hot without either rapidly sublimating or being blown out of the system.
On the precision of full-spectrum fitting of simple stellar populations – I. Well-sampled populations
Authors: Asa’d Randa , Goudfrooij Paul
Published: August 2020

We investigate the precision of the ages and metallicities of 21 000 mock simple stellar populations (SSPs) determined through full-spectrum fitting. The mock SSPs cover an age range of 6.8 < log (age/yr) < 10.2, for three wavelength ranges in the optical regime, using both Padova and MIST isochrone models. Random noise is added to the model spectra to achieve S/N ratios between 10 and 100 per wavelength pixel. We find that for S/N ≥ 50, this technique can yield ages of SSPs to an overall precision of ∆log (age/yr)∼01 for ages in the ranges 7.0 ≤ log (age/yr) ≤ 8.3 and 8.9 ≤ log (age/yr) ≤ 9.4. For the age ranges of 8.3 ≤ log (age/yr) ≤ 8.9 and log (age/yr) ≥ 9.5, which have significant flux contributions from asymptotic giant branch and red giant branch stars, respectively, the age uncertainty rises to about ±0.3 dex. The precision of age and metallicity estimation using this method depends significantly on the S/N and the wavelength range used in the fitting. We quantify the systematic differences in age predicted by the MIST and Padova isochrone models, due to their different assumptions about stellar physics in various important (i.e. luminous) phases of stellar evolution, which needs to be taken in consideration when comparing ages of star clusters obtained using these popular models. Knowing the strengths and limitations of this technique is crucial in interpreting the results obtained for real star clusters and for deciding the optimal instrument set-up before performing the observations.
Formation of superstrong horizontal magnetic field in delta-type sunspot in radiation magnetohydrodynamic simulations
Authors: Hotta H , Toriumi S
Published: August 2020

We perform a series of radiative magnetohydrodynamic simulations to understand the amplification mechanism of the exceptionally strong horizontal magnetic field in delta-type sunspots. In the simulations, we succeed in reproducing the delta-type sunspot and resulting strong magnetic field exceeding 6000 G in a light bridge between the positive and negative polarities. Our conclusions in this study are summarized as follows: (1) The essential amplification mechanism of the strong horizontal magnetic field is the shear motion caused by the rotation of two spots. (2) The strong horizontal magnetic field remains the force-free state. (3) The peak strength of the magnetic fields does not depend on the spatial resolution, top boundary condition, or Alfvén speed limit. The origin of the rotating motion is rooted in the deep convection zone. Therefore, the magnetic field in the delta-spot light bridge can be amplified to the superequipartition values in the photosphere.
Magnetizing the circumgalactic medium of disc galaxies
Authors: Pakmor Rüdiger , van de Voort Freeke , Bieri Rebekka , Gómez Facundo A , Grand Robert J J , Guillet Thomas , Marinacci Federico , Pfrommer Christoph , Simpson Christine M , Springel Volker
Published: August 2020

The circumgalactic medium (CGM) is one of the frontiers of galaxy formation and intimately connected to the galaxy via accretion of gas on to the galaxy and gaseous outflows from the galaxy. Here, we analyse the magnetic field in the CGM of the Milky Way-like galaxies simulated as part of the auriga project that constitutes a set of high-resolution cosmological magnetohydrodynamical zoom simulations. We show that before z = 1 the CGM becomes magnetized via galactic outflows that transport magnetized gas from the disc into the halo. At this time, the magnetization of the CGM closely follows its metal enrichment. We then show that at low redshift an in situ turbulent dynamo that operates on a time-scale of Gigayears further amplifies the magnetic field in the CGM and saturates before z = 0. The magnetic field strength reaches a typical value of $0.1\, \mu \mathrm{ G}$ at the virial radius at z = 0 and becomes mostly uniform within the virial radius. Its Faraday rotation signal is in excellent agreement with recent observations. For most of its evolution, the magnetic field in the CGM is an unordered small-scale field. Only strong coherent outflows at low redshift are able to order the magnetic field in parts of the CGM that are directly displaced by these outflows.
A magnetar parallax
Authors: Ding H , Deller A T , Lower M E , Flynn C , Chatterjee S , Brisken W , Hurley-Walker N , Camilo F , Sarkissian J , Gupta V
Published: August 2020

XTE J1810−197 (J1810) was the first magnetar identified to emit radio pulses, and has been extensively studied during a radio-bright phase in 2003–2008. It is estimated to be relatively nearby compared to other Galactic magnetars, and provides a useful prototype for the physics of high magnetic fields, magnetar velocities, and the plausible connection to extragalactic fast radio bursts. Upon the rebrightening of the magnetar at radio wavelengths in late 2018, we resumed an astrometric campaign on J1810 with the Very Long Baseline Array, and sampled 14 new positions of J1810 over 1.3 yr. The phase calibration for the new observations was performed with two-phase calibrators that are quasi-colinear on the sky with J1810, enabling substantial improvement of the resultant astrometric precision. Combining our new observations with two archival observations from 2006, we have refined the proper motion and reference position of the magnetar and have measured its annual geometric parallax, the first such measurement for a magnetar. The parallax of 0.40 ± 0.05 mas corresponds to a most probable distance $2.5^{\, +0.4}_{\, -0.3}$ kpc for J1810. Our new astrometric results confirm an unremarkable transverse peculiar velocity of ≈200 $\rm km~s^{-1}$ for J1810, which is only at the average level among the pulsar population. The magnetar proper motion vector points back to the central region of a supernova remnant (SNR) at a compatible distance at ≈70 kyr ago, but a direct association is disfavoured by the estimated SNR age of ∼3 kyr.
The impact of tidal disruption events on galactic habitability
Authors: Pacetti E , Balbi A , Lingam M , Tombesi F , Perlman E
Published: August 2020

Tidal disruption events (TDEs) are characterized by the emission of a short burst of high-energy radiation. We analyse the cumulative impact of TDEs on galactic habitability using the Milky Way as a proxy. We show that X-rays and extreme ultraviolet radiation emitted during TDEs can cause hydrodynamic escape and instigate biological damage. By taking the appropriate variables into consideration, such as the efficiency of atmospheric escape and distance from the Galactic centre, we demonstrate that the impact of TDEs on galactic habitability is comparable to that of active galactic nuclei. In particular, we show that planets within distances of ∼0.1–1 kpc could lose Earth-like atmospheres over the age of the Earth, and that some of them might be subject to biological damage once every ≳ 104 yr. We conclude by highlighting potential ramifications of TDEs and argue that they should be factored into future analyses of inner galactic habitability.
Compressing combined probes: redshift weights for joint lensing and clustering analyses
Authors: Ruggeri Rossana , Blake Chris
Published: August 2020

Combining different observational probes, such as galaxy clustering and weak lensing, is a promising technique for unveiling the physics of the Universe with upcoming dark energy experiments. Whilst this strategy significantly improves parameter constraints, decreasing the degeneracies of individual analyses and controlling the systematics, processing data from tens of millions of galaxies is not a trivial task. In this work, we derive and test a new compressed statistic for joint clustering and lensing data analysis, maximizing the scientific return and decreasing the computational cost. Our approach compresses the data by up-weighting the components most sensitive to the parameters of interest, with no loss of information, taking into account information from the cross-correlation between the two probes. We derive optimal redshift weights which may be applied to individual galaxies when testing a given statistic and cosmological model.