bluuebunny/crossref_metadata_2025 huggingface dataset:
Background Subtraction using Adaptive Singular Value Decomposition
Authors: Reitberger Günther , Sauer Tomas
Published: June 2020

An important task when processing sensor data is to distinguish relevant from irrelevant data. This paper describes a method for an iterative singular value decomposition that maintains a model of the background via singular vectors spanning a subspace of the image space, thus providing a way to determine the amount of new information contained in an incoming frame. We update the singular vectors spanning the background space in a computationally efficient manner and provide the ability to perform blockwise updates, leading to a fast and robust adaptive SVD computation. The effects of those two properties and the success of the overall method to perform a state-of-the-art background subtraction are shown in both qualitative and quantitative evaluations.
Surgical treatment of aggressive pituitary adenomas and pituitary carcinomas
Authors: Buchfelder Michael , Schlaffer Sven-Martin
Published: June 2020

Surgery of aggressive pituitary adenomas and pituitary carcinomas is part of the interdisciplinary management of these difficult to treat tumors. Invasion, giant size and unusual, asymmetric extent of these tumors frequently require modifications or extensions of the standard approaches for transsphenoidal and transcranial surgery. Frequently, only debulking procedures can be performed. In aggressive and hormone secreting adenomas, the remission rates achieved by surgery alone are relatively poor and adjuvant medical treatments or irradiation are needed. Safe resection of as much tumor as possible and symptomatic control is aimed at, rather than remission. Many procedures are required for rapid progression of lesions or recurrences, in order to extend the survival of the patients. Metastases of pituitary carcinomas within the cranial cavity or spine can be attacked. Since they can occur anywhere in the brain or spinal canal they require the entire battery of neurosurgical approaches. Unfortunately, in this group of pituitary tumors, the complication rates are higher than in primary operations of enclosed adenomas. The respective techniques with their facilities and limitations are reviewed in this article.
Estimation of intergenerational mobility in small samples: evidence from German survey data
Authors: Kyzyma Iryna , Groh-Samberg Olaf
Published: June 2020

Using data from the German socio-economic panel, this paper provides new evidence on intergenerational mobility in Germany by focusing on intergenerational association in ranks—i.e. positions, which parents and children occupy in their respective income distributions. We find that the association of children’s ranks with ranks of their fathers is about 0.242 for individual labor earnings and it is higher for sons than for daughters. It is also higher in East Germany compared to West Germany. The results further show that rank-based measures of mobility are less sensitive than conventional measures of intergenerational income elasticity to different methodological and sample specification choices, such as the stages of the life cycle when incomes of children and parents are measured, the number of years for which incomes are considered, the treatment of zero values in income variables and the choice of annual versus hourly earnings. Moreover, they are more robust for sub-group comparisons of intergenerational mobility (e.g. across gender and region). This evidence suggests that, similarly to large administrative datasets, rank-based measures of intergenerational mobility perform better than elasticity-based measures in small samples based on survey data.
Long-term monitoring of the recruitment and dynamics of large wood in Kamienica Stream, Polish Carpathians
Authors: Mikuś Paweł , Wyżga Barłomiej
Published: June 2020

Studies presenting long-term observations of the recruitment and mobility of large wood in mountain watercourses are scarce, but they can considerably contribute to the knowledge of river/riparian forest interactions and the assessment of flood hazard resulting from wood mobility during floods. Widespread dieback of riparian forest along the headwater course of Kamienica Stream in the Polish Carpathians, caused by bark beetle infestation of spruce trees, has raised concerns about potential increases of large wood recruitment to the stream and of the flood hazard to downstream valley reaches. In October 2009, 429 trees growing along three sections of the stream were tagged with numbered metal plates and monitored over 10 years to determine the timing and causes of their delivery to the channel and the lengths of their displacement during individual flood events. Moreover, in 2012 the mode of location of wood deposits and a degree of wood decay were determined in the second- to fourth-order stream reaches. The monitoring of tagged trees indicated that trees were recruited to the channel during highintensity meteorological and hydrological events, mostly as a result of bank erosion during floods or windthrow. With 22% of tagged trees recruited to the channel during 10 years, the rate of turnover of the riparian trees was estimated at 45 years. As the riparian area is overgrown with trees with ages up to ~160 years, the rate evidences substantial intensification of large wood recruitment to the channel in the recent period. Results of large wood inventory and the 10-year-long monitoring of tagged trees indicated variable mobility of large wood along the upper course of the stream. Wood mobility was negligible in the second-order stream reach, very small in the third-order reach, and greater, but still limited in the fourth-order reach. Wood is transported longer distances only during major floods. However, the advanced state of decay of most pieces leads to their disintegration during floods, precluding distant transport. Thus, large wood retained in the upper stream course does not constitute an important flood hazard to downstream, inhabited valley reaches.
Microbial Interaction Network Estimation via Bias-Corrected Graphical Lasso
Authors: Jiang Duo , Sharpton Thomas , Jiang Yuan
Published: June 2020

With the increasing availability of microbiome 16S data, network estimation has become a useful approach to studying the interactions between microbial taxa. Network estimation on a set of variables is frequently explored using graphical models, in which the relationship between two variables is modeled via their conditional dependency given the other variables. Various methods for sparse inverse covariance estimation have been proposed to estimate graphical models in the high-dimensional setting, including graphical lasso. However, current methods do not address the compositional count nature of microbiome data, where abundances of microbial taxa are not directly measured, but are reflected by the observed counts in an error-prone manner. Adding to the challenge is that the sum of the counts within each sample, termed “sequencing depth,” is an experimental technicality that carries no biological information but can vary drastically across samples. To address these issues, we develop a new approach to network estimation, called BC-GLASSO (bias-corrected graphical lasso), which models the microbiome data using a logistic normal multinomial distribution with the sequencing depths explicitly incorporated, corrects the bias of the naive empirical covariance estimator arising from the heterogeneity in sequencing depths, and builds the inverse covariance estimator via graphical lasso. We demonstrate the advantage of BC-GLASSO over current approaches to microbial interaction network estimation under a variety of simulation scenarios. We also illustrate the efficacy of our method in an application to a human microbiome data set.
Thermochemical equilibrium study of ash transformation during combustion and gasification of sewage sludge mixtures with agricultural residues with focus on the phosphorus speciation
Authors: Hannl Thomas Karl , Sefidari Hamid , Kuba Matthias , Skoglund Nils , Öhman Marcus
Published: June 2020

The necessity of recycling anthropogenically used phosphorus to prevent aquatic eutrophication and decrease the economic dependency on mined phosphate ores encouraged recent research to identify potential alternative resource pools. One of these resource pools is the ash derived from the thermochemical conversion of sewage sludge. This ash is rich in phosphorus, although most of it is chemically associated in a way where it is not plant available. The aim of this work was to identify the P recovery potential of ashes from sewage sludge co-conversion processes with two types of agricultural residues, namely wheat straw (rich in K and Si) and sunflower husks (rich in K), employing thermodynamic equilibrium calculations. The results indicate that both the melting behavior and the formation of plant available phosphates can be enhanced by using these fuel blends in comparison with pure sewage sludge. This enhanced bioavailability of phosphates was mostly due to the predicted formation of K-bearing phosphates in the mixtures instead of Ca/Fe/Al phosphates in the pure sewage sludge ash. According to the calculations, gasification conditions could increase the degree of slag formation and enhance the volatilization of K in comparison with combustion conditions. Furthermore, the possibility of precipitating phosphates from ash melts could be shown. It is emphasized that the results of this theoretical study represent an idealized system since in practice, non-equilibrium influences such as kinetic limitations and formation of amorphous structures may be significant. However, applicability of thermodynamic calculations in the prediction of molten and solid phases may still guide experimental research to investigate the actual phosphate formation in the future.
Are we generating more assessments without added value? Surgical trainees’ perceptions of and receptiveness to cross-specialty assessment
Authors: Burm Sarah , Sebok-Syer Stefanie S. , Van Koughnett Julie Ann , Watling Christopher J.
Published: June 2020

Introduction Competency-based medical education (CBME) hinges on robust assessment. However, integrating regular workplace-based assessment within demanding and sometimes chaotic clinical environments remains challenging. Many faculty lack assessment expertise, and some programs lack the infrastructure and faculty numbers to fulfill CBME’s mandate. Recognizing this, we designed and implemented an assessment innovation that trains and deploys a cadre of faculty to assess in specialties outside their own. Specifically, we explored trainees’ perceptions of and receptiveness to this novel assessment approach.

Methods Within Western University’s Surgical Foundations program, 27 PGY‑1 trainees were formatively assessed by trained non-surgeons on a basic laparoscopic surgical skill. These assessments did not impact trainees’ progression. Four focus groups were conducted to gauge residents’ sentiments about the experience of cross-specialty assessment. Data were then analyzed using a thematic analysis approach.

Results While a few trainees found the experience motivating, more often trainees questioned the feedback they received and the practicality of this assessment approach to advance their procedural skill acquisition. What trainees wanted were strategies for improvement, not merely an assessment of performance.

Discussion Trainees’ trepidation at the idea of using outside assessors to meet increased assessment demands appeared grounded in their expectations for assessment. What trainees appeared to desire was a coach—someone who could break their performance into its critical individual components—as opposed to an assessor whose role was limited to scoring their performance. Understanding trainees’ receptivity to new assessment approaches is crucial; otherwise training programs run the risk of generating more assessments without added value.
Single-source-precursor synthesis and phase evolution of SiC-TaC-C ceramic nanocomposites containing core-shell structured TaC@C nanoparticles
Authors: Yu Zhaoju , Yang Yujing , Mao Kangwei , Feng Yao , Wen Qingbo , Riedel Ralf
Published: June 2020

A novel single-source-precursor for SiC-TaC-C nanocomposites was successfully synthesized by the chemical reaction between a polycarbosilane (allylhydridopolycarbosilane, AHPCS) and tantalum(V) chloride (TaCl5), which was confirmed by Fourier transform infrared spectra (FTIR) measurement. After pyrolysis of the resultant single-source-precursors at 900 °C, amorphous ceramic powders were obtained. The 900 °C ceramics were annealed at different temperatures in the range of 1200–1600 °C to gain SiC-TaC-C nanocomposites. The phase evolution of ceramic nanocomposites was investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results indicate that the TaC starts to crystallize at lower temperature than the β-SiC. It is particularly worth pointing out that the unique core-shell structured TaC@C nanoparticles werein-situformed and homogeneously distributed in the ceramic matrix after annealing at 1400 °C. Even at a high temperature of 1600 °C, the grain sizes of β-SiC and TaC are smaller than 30 nm, fulfilling the definition of nanocomposites. The present study related to SiC-TaC-C nanocomposites paves a new road for enriching ultra-high temperature ceramic family suitable for structural/functional applications in harsh environment.
Review of research on high-speed railway subgrade settlement in soft soil area
Authors: Zhou Shunhua , Wang Binglong , Shan Yao
Published: June 2020

Construction issues of high-speed rail infrastructures have been increasingly concerned worldwide, of which the subgrade settlement in soft soil area becomes a particularly critical problem. Due to the high compressibility and low permeability of soft soil, the post-construction settlement of the subgrade is extremely difficult to control in these regions, which seriously threatens the operation safety of high-speed trains. In this work, the significant issues of high-speed railway subgrades in soft soil regions are discussed. The theoretical and experimental studies on foundation treatment methods for ballasted and ballastless tracks are reviewed. The settlement evolution and the settlement control effect of different treatment methods are highlighted. Control technologies of subgrade differential settlement are subsequently briefly presented. Settlement calculation algorithms of foundations reinforced by different treatment methods are discussed in detail. The defects of existing prediction methods and the challenges faced in their practical applications are analyzed. Furthermore, the guidance on future improvement in control theories and technologies of subgrade settlement for high-speed railway lines and the corresponding challenges are provided.
Is the Motor Impairment in Attention Deficit Hyperactivity Disorder (ADHD) a Co-Occurring Deficit or a Phenotypic Characteristic?
Authors: Farran Emily K. , Bowler Aislinn , D’Souza Hana , Mayall Leighanne , Karmiloff-Smith Annette , Sumner Emma , Brady Daniel , Hill Elisabeth L.
Published: June 2020

Objectives

Motor difficulties are often reported in individuals with attention deficit hyperactivity disorder (ADHD). The aims of this study are to detail the motor profile of children with ADHD and to determine whether the motor impairment present in a large proportion of children with ADHD represents a phenotypic characteristic of ADHD or a co-occurring deficit.

Methods

Participants with ADHD (N = 51; age 8 to 15 years) and typically developing (TD) motor matched control children (N = 75; age 4 to 11 years) completed the largest battery of assessments of motor function that have been used with this population to date, as well as a measure of inhibition as a behavioural measure of ADHD characteristics. Parents/caregivers also completed questionnaires relating to ADHD symptomology and a retrospective report of their child’s motor milestone achievement.

Results

A motor deficit was observed in 47% of our ADHD sample. Few relationships were observed between ADHD core characteristics and motor competence. Furthermore, there was an uneven profile of motor performance across different motor tasks, relative to the TD children. Interestingly, it appears that motor milestone achievement is not delayed in ADHD.

Conclusions

Our findings suggest that the motor deficit observed in ADHD is not inherent to ADHD. The motor deficit observed in some children with ADHD does not represent a simple delay in development and is not observed in infancy with respect to reaching motor milestones.
Understanding current practice of opioid use disorder management in emergency departments across Canada: A cross-sectional study
Authors: Hoyeck Patricia , Wiercigroch David , Clarke Cara , Moineddin Rahim , Sheikh Hasan , Hulme Jennifer
Published: June 2020

Objective

Opioid-related deaths are increasing at alarming rates in Canada, with a 34% increase from 2016 to 2017. Patients with opioid use disorder often visit emergency departments (ED), presenting an opportunity to engage patients in treatment. Buprenorphine-naloxone is first-line treatment for opioid use disorder, but current management in the ED is unknown. This study aimed to characterize opioid use disorder management in the ED.

Methods

We conducted a cross-sectional study of emergency physicians across Canada. A survey was circulated electronically to the Canadian Association of Emergency Physicians members. Participants were asked about their current management practices, satisfaction, and helpfulness of resources. SAS (version 9.4) was used for statistical analysis. We dichotomized Likert-scale responses to approximate relative risk ratios via a log binomial analysis.

Results

The survey was completed by 179 participants for a response rate of 11.1%; 143 (79.9%) physicians treated patients with opioid use disorder more than once a week. Only 7% (n = 13) of respondents always/often gave buprenorphine in the ED. Referral to an addiction clinic where patients were seen quickly was deemed the most helpful (90.5%, n = 162). Physicians who reported satisfaction with opioid use disorder management were four times more likely to prescribe buprenorphine in the ED or as an outpatient script (RR = 4.41, CI = 2.33–8.33, p < 0.01; RR = 4.51, CI = 2.21–9.22, p < 0.01).

Conclusion

This study found that buprenorphine is not frequently prescribed in the ED setting, which is incongruent with the 2018 guidelines. Care coordination and on-site support were helpful to ED physicians. Hospitals should use knowledge translation strategies to improve the care of patients with an opioid use disorder.
“Do Not Do Abroad What You Would Not Do at Home?”: An Exploration of the Rationales for Extraterritorial Criminal Jurisdiction over a State’s Nationals
Authors: MÉGRET FRÉDÉRIC
Published: June 2020

Compared to universal jurisdiction, active nationality jurisdiction remains one of the least understood and written about forms of extraterritorial criminal jurisdiction. This article seeks to offer a normative account of the exercise of criminal jurisdiction by states over their nationals for crimes committed abroad such as sexual offences against minors, bribery of foreign public officials, or medical “circumvention” tourism. It highlights all of the reasons that militate against such assertions of jurisdiction as a matter of policy and law. It goes on to argue that the assertion of criminal jurisdiction over nationals for crimes committed abroad must be understood beyond its permissibility under international law as a modality that manifests the interests of the state of nationality, the territorial (host) state on occasion, the relevant individuals, and, increasingly, the international community.
Landau–Kelly representation of statistical thermodynamics of a quantum plasma and electron emission from metals
Authors: Tsintsadze L. N. , Peradze G. M. , Tsintsadze N. L.
Published: June 2020

We have investigated the influence of a strong magnetic field on various aspects of a quantum Fermi plasma. Due to the strong magnetic field, the distribution function becomes anisotropic. First, we consider non-degenerate quantum, Landau and Kelly distribution function. It was found that the adiabatic equation is similar to the adiabatic equation for a Maxwell distribution function, when we include the magnetic field in the energy expression. Using the Kelly distribution for a degenerate, quantum Fermi gas, parallel and perpendicular components of the pressure were derived. It was found that perpendicular component of pressure never becomes zero and three-dimensional system always stay three-dimensional. Lastly, we investigated electron emission from metals and have shown the influence of the magnetic field. We calculated thermionic emission, the so-called Richardson effect. In addition, we investigate the influence of external electromagnetic radiation on the electron current density (Hallwachs effect) from metals.
Carrying a patibulum: A Reassessment of Non-Christian Latin Sources
Authors: van Wingerden Ruben
Published: June 2020

That Jesus carried the horizontal bar of the cross, also named patibulum, is often assumed, and argued by John Granger Cook. Gunnar Samuelsson disagrees, however, and argued that we grope in the dark about the exact nature of the σταυρός that Jesus carried. Both major crucifixion scholars refer in their argumentation to Latin sources in which a patibulum is carried. But these sources have not been thoroughly assessed on their own. In this article the eight Latin sources mentioned in support of the ancient practice are analysed. It is argued that only four of these sources should be counted as referring to ‘traditional’ cross-bearing practices.
Documenting the acquisition of indigenous languages
Authors: PYE Clifton
Published: June 2020

The outstanding property of human language is its diversity, and yet acquisition data is only available for three percent of the world's 6000+ spoken languages. Due to the rapid pace of language loss, it may not be possible to document how children acquire half of the world's indigenous languages in as little as two decades. This loss permanently diminishes the scope of acquisition theory by removing its empirical base. In the face of pervasive language loss, the question of how best to document the language of the last children to acquire indigenous languages assumes critical importance. A collaborative effort by researchers is required to identify the most efficient procedures for documenting children's language, and share them worldwide. This paper makes the case for documenting diversity and outlines steps needed to accomplish this goal.
Where Does Open Science Lead Us During a Pandemic? A Public Good Argument to Prioritize Rights in the Open Commons
Authors: CAPPS BENJAMIN
Published: June 2020

During the 2020 COVID-19 pandemic, open science has become central to experimental, public health, and clinical responses across the globe. Open science (OS) is described as an open commons, in which a right to science renders all possible scientific data for everyone to access and use. In this common space, capitalist platforms now provide many essential services and are taking the lead in public health activities. These neoliberal businesses, however, have a problematic role in the capture of public goods. This paper argues that the open commons is a community of rights, consisting of people and institutions whose interests mutually support the public good. If OS is a cornerstone of public health, then reaffirming the public good is its overriding purpose, and unethical platforms ought to be excluded from the commons and its benefits.
Relation of visceral fat and haemodynamics in adults with Fontan circulation
Authors: Lubert Adam M. , Alsaied Tarek , Trout Andrew T. , Dillman Jonathan R. , Goldstein Bryan H.
Published: June 2020

Being overweight is associated with reduced functional capacity in Fontan patients. Increased adiposity leads to accumulation of epicardial and intra-abdominal visceral fat, which produce proinflammatory cytokines and may affect endothelial function. This retrospective study to evaluate the association between visceral fat and Fontan haemodynamics included 23 Fontan patients >18 years old with MRI and catheterization data available. Epicardial fat volume indexed to body surface area was measured by cardiac MRI, and intra-abdominal visceral fat thickness and subcutaneous fat thickness were derived from abdominal MRI. Stepwise regression models were used to determine univariable and multivariable associations between fat measures and haemodynamics. Mean age was 28.2 ± 9.5 years and body mass index was 26 ± 4 kg/m2. Mean central venous pressure was 13 ± 3 mmHg and pulmonary vascular resistance index was 1.23WU·m2 (interquartile range: 0.95–1.56). Epicardial fat volume was associated with age (r2 = 0.37, p = 0.002), weight (r2 = 0.26, p = 0.013), body mass index (r2 = 0.27, p = 0.011), and intra-abdominal visceral fat (r2 = 0.30, p = 0.018). Subcutaneous fat thickness did not relate to these measures. There was modest correlation between epicardial fat volume and pulmonary vascular resistance (r2 = 0.27, p = 0.02) and a trend towards significant correlation between intra-abdominal fat thickness and pulmonary vascular resistance (r2 = 0.21, p = 0.06). Subcutaneous fat thickness was not associated with Fontan haemodynamics. In multivariable analysis, including age and visceral fat measures, epicardial fat was independently correlated with pulmonary vascular resistance (point estimate 0.13 ± 0.05 per 10 ml/m2 increase, p = 0.03). In conclusion, in adults with Fontan circulation, increased visceral fat is associated with higher pulmonary vascular resistance. Excess visceral fat may represent a therapeutic target to improve Fontan haemodynamics.
Understanding galaxy formation in the reionization era using the FIRE simulations
Authors: Ma Xiangcheng
Published: June 2020

We present a suite of high-resolution cosmological zoom-in simulations of galaxies at z⩾ 5using the state-of-the-art models for the multi-phase ISM, star formation, and stellar feedback from the FIRE project. We present a series of key results from these simulations, including the stellar mass–halo mass relation, the ultraviolet luminosity functions, dust attenuation and dust temperatures, the ubiquitous formation of bound star clusters, morphology and clumpiness, and the escape fractions of ionizing photons from high-redshift galaxies. We discuss how different simulations in the literature agree and disagree and what observations are most useful for testing the models in the era of ALMA and JWST.
Resolving distant, dusty galaxies using observations and simulations
Authors: Cochrane R. K.
Published: June 2020

Spatially resolved studies of galaxies in the high-redshift Universe have traditionally been reliant on data at rest-frame optical and UV wavelengths, which can be biased towards the least dust-obscured galaxies. For several years now, we have been able to resolve and probe the morphology of longer-wavelength emission from distant galaxies with ALMA, and a number of recent ALMA studies were presented at the IAU Symposium No. 352. These included our study of the resolved multi-wavelength emission of galaxies at z ∼ 2. As part of the SHiZELS collaboration, we are mapping the Hα emission line (from SINFONI/VLT), UV continuum (from HST), and the far-infrared (from ALMA) emission from a small sample of Hα-selected galaxies. In this proceedings paper, we showcase the high quality of our data, and the spectacular structures displayed by one of our most dusty sources. We also provide an overview of some highly complementary simulation-based work, using galaxies drawn from the FIRE-2 zoom-in cosmological hydrodynamical simulations. Using sophisticated radiative transfer techniques, we have derived predictions for the spatially-resolved emission of a sample of star-forming galaxies, from rest-frame far-ultraviolet to the far-infrared. For both observed and simulated galaxies, emission maps show striking differences with wavelength, with the same galaxy appearing clumpy and extended in the far-ultraviolet yet compact at far-infrared wavelengths.
Near-IR spectroscopic studies of galaxies at z ∼ 1–3
Authors: Shivaei Irene
Published: June 2020

ISM comprises multiple components, including molecular, neutral, and ionized gas, and dust, which are related to each other mainly through star formation – some are fuel for star formation (molecular gas) while some are the products of it (ionized gas, dust). To fully understand the physics of star formation and its evolution throughout cosmic time, it is crucial to measure and observe different ISM components of galaxies out to high redshifts. I will review the current status of near-IR studies of galaxies during the peak of star formation activity (z ∼ 1 – 3). Using rest-frame optical emission lines, we measure dust, star formation, and gaseous properties of galaxies. JWST will advance such studies by probing lower luminosities and higher redshifts, owing to its significantly higher sensitivity. Incorporating ALMA observations of cold dust and molecular gas at z > 1 will give us a nearly complete picture of the ISM in high-redshift galaxies over a large dynamic range in mass.
Towards the first radio galaxies
Authors: Matute Israel , Afonso Jose , Bizzocchi Luca , Pappalardo Cirino , Messias Hugo , Amarantidis Stergios
Published: June 2020

Powerful AGN have been detected up to very high redshifts (z ∼ 6–8), well within the Epoch of Reionization (EoR), but the lack of powerful radio-galaxies among such sources strongly disagrees with the expectations based on the known radio population up to z ∼ 5. Our group has been pursuing a detailed analysis of the faintest population of radio sources detected in the deepest fields searching for clues of these first radio galaxies. This paper describes our strategy and presents a highly confident candidate. The results, once follow-up of all candidates is completed, will have significant implications for the upcoming generation of all-sky deep radio surveys such as ASKAP-EMU, Westerbork-WODAN, and SKA itself.
Unveiling the most luminous Lyman-α emitters in the epoch of reionisation
Authors: Matthee Jorryt , Sobral David
Published: June 2020

Distant luminous Lyman-α emitters are excellent targets for detailed observations of galaxies in the epoch of reionisation. Spatially resolved observations of these galaxies allow us to simultaneously probe the emission from young stars, partially ionised gas in the interstellar medium and to constrain the properties of the surrounding hydrogen in the circumgalactic medium. We review recent results from (spectroscopic) follow-up studies of the rest-frame UV, Lyman-α and [CII] emission in luminous galaxies observed ∼500 Myr after the Big Bang with ALMA, HST/WFC3 and VLT/X-SHOOTER. These galaxies likely reside in early ionised bubbles and are complex systems, consisting of multiple well separated and resolved components where traces of metals are already present.
Luminous and dark matter density profiles in the inner regions of a group-scale lens at z = 0.6
Authors: Tergolina Mônica , Furlanetto Cristina , Trevisan Marina
Published: June 2020

Density profiles of galaxy groups can provide an insight on how large-scale structure in the Universe formed and evolved, since galaxy groups bridge the gap between individual galaxies and galaxy clusters. Studying the galaxy group that is gravitational lensing HELMS18, a submillimeter galaxy at z = 2.39 from the Herschel’s HerMES Large Mode Survey (HELMS), we aim to probe the total density profile by combining strong gravitational lensing with kinematics of the centrally-located galaxies and kinematics of the group members. We have high-resolution data of HELMS18 obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) and multi-object spectroscopic data of the group members from Gemini-GMOS. Our main goal is to match these observations to probe the DM and stellar density profiles and to establish a complete description of this galaxy group.
Connecting black holes and galaxies in faint radio populations at cosmic noon
Authors: Alberts Stacey , Rujopakarn Wiphu , Rieke George H.
Published: June 2020

We leverage new ultra-deep, high resolution, multi-frequency radio imaging at 6 and 3 GHz with the unique datasets available in the GOODS-S/HUDF region in order to assess the AGN fraction in a faint radio-selected sample. For AGN identification, we adopt a multi-wavelength approach, combining X-ray and (mid-)infrared (IR) selections with radio identification such as X-ray to radio excess, flat radio spectral slopes, and the radio-IR correlation. We identify AGN in 43% of our radio sample, yielding an AGN source density of ∼ 1 arcmin−2. This AGN fraction is likely underestimated, as 1) our shallower 3 GHz data is biased against flat radio spectrum sources and 2) all of our selections may be biased against the most heavily obscured AGN. The James Webb Space Telescope’s Mid-Infrared Instrument (MIRI) will address the latter issue and we briefly outline our Cycle 1 Guaranteed Time Observation (GTO) program to search for heavily obscured AGN.
Synthetic nebular emission lines of simulated galaxies over cosmic time
Authors: Hirschmann Michaela
Published: June 2020

This article presents an up-dated analysis of synthetic optical and UV emission lines of simulated galaxies over cosmic time. The strong emission lines are derived from self-consistently coupling novel spectral models accounting for nebular emission from young stars, AGN and Post-AGB stars to cosmological zoom-in as well as large-scale simulations. Investigating the evolution of optical line-ratios in the BPT diagrams, the simulations can successfully reproduce the observed trend of [OIII]/Hβ ratio increasing from low to high redshifts, due to evolving star formation rate and gas metallicity. Standard selection criteria in the BPT diagrams can appropriately distinguish the main ionising source(s) of galaxies at low redshifts, but they are less reliable for metal-poor galaxies, dominating the early Universe. To robustly classify the ionising radiation of such metal-poor galaxies, diagnostic diagrams based on luminosity ratios of UV lines are discussed. The novel interface between simulations and observations is potentially important for the interpretation of high-quality spectra of very distant galaxies to be gathered by next-generation telescopes, such as the James Webb Space Telescope.
Measuring the stellar initial mass function
Authors: Hopkins Andrew
Published: June 2020

The birth of stars and the formation of galaxies are cornerstones of modern astrophysics. While much is known about how galaxies globally and their stars individually form and evolve, one fundamental property that affects both remains elusive. This is problematic because this key property, the stellar initial mass function (IMF), is a key tracer of the physics of star formation that underpins almost all of the unknowns in galaxy and stellar evolution. It is perhaps the greatest source of systematic uncertainty in star and galaxy evolution. The past decade has seen a growing number and variety of methods for measuring or inferring the shape of the IMF, along with progressively more detailed simulations, paralleled by refinements in the way the concept of the IMF is applied or conceptualised on different physical scales. This range of approaches and evolving definitions of the quantity being measured has in turn led to conflicting conclusions regarding whether or not the IMF is universal. Here I summarise the growing wealth of approaches to our understanding of this fundamental property that defines so much of astrophysics, and highlight the importance of considering potential IMF variations, reinforcing the need for measurements to quantify their scope and uncertainties carefully. I present a new framework to aid the discussion of the IMF and promote clarity in the further development of this fundamental field.
ALMA reveals large molecular gas reservoirs in recently-quenched galaxies
Authors: Suess Katherine
Published: June 2020

We still do not understand the physical mechanisms that are responsible for suppressing star formation in galaxies. Observations of post-starburst galaxies, whose spectra indicate that an intense period of star formation was followed by rapid quenching, are the ideal sample to probe the quenching process. We have conducted an ALMA survey of CO(2-1) in 13 of these recently- quenched galaxies at z ∼ 0.7 – high enough redshift that these galaxies likely just concluded their primary epoch of star formation, but low enough redshift for follow-up observations to be feasible. Our observations reveal a stunning diversity of molecular gas properties: despite a uniform optical selection and low apparent SFRs, the detected galaxies span a factor of > 30 in CO luminosity and have inferred gas fractions ranging from < 1% to 20%. These observations indicate that quenching does not require the total removal or depletion of molecular gas. No current models of the quenching process can fully explain our results.
Connecting observations of the first galaxies and the Epoch of Reionisation
Authors: Mutch Simon
Published: June 2020

Dwarf galaxies are thought to be dominant contributors of ionizing photons during the Epoch of Reionisation (EoR). Our knowledge of the statistics of these high redshift galaxies is constantly improving and will take yet another important step forward with the launch of JWST. At the same time, the upper limits on the EoR 21cm power spectrum are continually falling, with a firm measurement from SKA-low being a certainty in coming years. In order to maximise what we can learn from these two complimentary observational datasets, we need to be able to model them together, self-consistently. In this talk, I will present insights into the connection between galaxy formation and the EoR gained from the DRAGONS suite of semi-analytic and hydrodynamic galaxy formation simulations. Using these we find that the steep faint end slope of the high- redshift galaxy UV luminosity function extends well beyond current observational limits, indicating that only ∼ 50% of the ionising photons available for reionisation have been observed at z < 7. I will also discuss the relative contribution of quasars to reionisation and present constraints on ionising escape fraction models.
The brightest galaxies in the dark ages: Galaxies’ dust continuum emission out to the reionization era
Authors: Casey Caitlin
Published: June 2020

Though half of cosmic starlight is absorbed by dust and reradiated at long wavelengths (3μ m – 3 mm), constraints on the infrared through millimeter galaxy luminosity function (the ‘IRLF’) are poor in comparison to the rest-frame ultraviolet and optical galaxy luminosity function, particularly at z ⩾ 2.5. Here we present a backward evolution model for interpreting number counts, redshift distributions, and cross-band flux density correlations in the infrared and submillimeter sky, from 70μm – 2 mm, using a model for the IRLF out to the epoch of reionization. Mock submillimeter maps are generated by injecting sources according to the prescribed IRLF and flux densities drawn from model spectral energy distributions that mirror the distribution of SEDs observed in 0 < z 0 < 5 dusty star-forming galaxies (DSFGs). We explore two extreme hypothetical case-studies: a dust-poor early Universe model, where DSFGs contribute negligibly (< 10%) to the integrated star-formation rate density at z > 4, and an alternate dust-rich early Universe model, where DSFGs dominate > 90% of z > 4 star-formation. We find that current submm/mm datasets do not clearly rule out either of these extreme models. We suggest that future surveys at 2 mm – both from ALMA and single-dish facilities – will be crucial to measuring the IRLF beyond z > 4.
Nine Outstanding Questions of Solar Wind Physics
Authors: Viall Nicholeen M. , Borovsky Joseph E.
Published: June 2020

In situ measurements of the solar wind have been available for almost 60 years, and in that time plasma physics simulation capabilities have commenced and ground‐based solar observations have expanded into space‐based solar observations. These observations and simulations have yielded an increasingly improved knowledge of fundamental physics and have delivered a remarkable understanding of the solar wind and its complexity. Yet there are longstanding major unsolved questions. Synthesizing inputs from the solar wind research community, nine outstanding questions of solar wind physics are developed and discussed in this commentary. These involve questions about the formation of the solar wind, about the inherent properties of the solar wind (and what the properties say about its formation), and about the evolution of the solar wind. The questions focus on (1) origin locations on the Sun, (2) plasma release, (3) acceleration, (4) heavy‐ion abundances and charge states, (5) magnetic structure, (6) Alfven waves, (7) turbulence, (8) distribution‐function evolution, and (9) energetic‐particle transport. On these nine questions we offer suggestions for future progress, forward looking on what is likely to be accomplished in near future with data from Parker Solar Probe, from Solar Orbiter, from the Daniel K. Inouye Solar Telescope (DKIST), and from Polarimeter to Unify the Corona and Heliosphere (PUNCH). Calls are made for improved measurements, for higher‐resolution simulations, and for advances in plasma physics theory.
A Persistent Kuroshio in the Glacial East China Sea and Implications for Coral Paleobiogeography
Authors: Vogt‐Vincent N. S. , Mitarai S.
Published: June 2020

The Kuroshio Current is a major hydrographical feature of the modern East China Sea, but it has been suggested that its flow was diverted to the east of the Ryukyu Arc at the Last Glacial Maximum. Shoaling of the Yonaguni Depression has also been proposed as a cause of Kuroshio Current diversion which, while unlikely to have been significant at the Last Glacial Maximum, may have been an important consideration further back in time. Using an ensemble of high‐resolution ocean simulations with climatic boundary conditions emulating those of the Last Glacial Maximum, we present the first regional state estimates of the glacial East China Sea which are both physically consistent and compatible with sea surface temperature proxy compilations. We find that while the Kuroshio Current transport in the East China Sea is slightly reduced at the Last Glacial Maximum, its path is relatively unchanged, with limited sensitivity to glacioeustatic sea level change, glacial‐interglacial changes in climate, and tectonic shoaling of the Yonaguni Depression. Simulations with the best model‐proxy agreement predict only limited contraction of the reef front at the Last Glacial Maximum, and strong surface currents associated with the glacial Kuroshio may have maintained or even improved long‐distance coral larval dispersal along the Ryukyu Arc, suggesting that conditions may have enabled coral reefs in this region to remain widespread throughout the last glacial. Further field studies investigating whether this is genuinely the case will provide insights into how the coral reef front responds to long‐term environmental change.
Direct nanoscopic observation of plasma waves in the channel of a graphene field-effect transistor
Authors: Soltani Amin , Kuschewski Frederik , Bonmann Marlene , Generalov Andrey , Vorobiev Andrei , Ludwig Florian , Wiecha Matthias M. , Čibiraitė Dovilė , Walla Frederik , Winnerl Stephan , Kehr Susanne C. , Eng Lukas M. , Stake Jan , Roskos Hartmut G.
Published: June 2020

Plasma waves play an important role in many solid-state phenomena and devices. They also become significant in electronic device structures as the operation frequencies of these devices increase. A prominent example is field-effect transistors (FETs), that witness increased attention for application as rectifying detectors and mixers of electromagnetic waves at gigahertz and terahertz frequencies, where they exhibit very good sensitivity even high above the cut-off frequency defined by the carrier transit time. Transport theory predicts that the coupling of radiation at THz frequencies into the channel of an antenna-coupled FET leads to the development of a gated plasma wave, collectively involving the charge carriers of both the two-dimensional electron gas and the gate electrode. In this paper, we present the first direct visualization of these waves. Employing graphene FETs containing a buried gate electrode, we utilize near-field THz nanoscopy at room temperature to directly probe the envelope function of the electric field amplitude on the exposed graphene sheet and the neighboring antenna regions. Mapping of the field distribution documents that wave injection is unidirectional from the source side since the oscillating electrical potentials on the gate and drain are equalized by capacitive shunting. The plasma waves, excited at 2 THz, are overdamped, and their decay time lies in the range of 25–70 fs. Despite this short decay time, the decay length is rather long, i.e., 0.3-0.5 μm, because of the rather large propagation speed of the plasma waves, which is found to lie in the range of 3.5–7 × 106 m/s, in good agreement with theory. The propagation speed depends only weakly on the gate voltage swing and is consistent with the theoretically predicted $$\frac{1}{4}$$

1

4

power law.
Maternal cariprazine exposure inhibits embryonic and postnatal brain cholesterol biosynthesis
Authors: Genaro-Mattos Thiago C. , Anderson Allison , Allen Luke B. , Tallman Keri A. , Porter Ned A. , Korade Zeljka , Mirnics Károly
Published: June 2020

Cariprazine (CAR) is a strong inhibitor of the Dhcr7 enzyme, the last enzyme in the cholesterol biosynthesis pathway. We assessed the effects of CAR on maternally exposed Dhcr7+/− and wild-type mouse offspring, and tested the biochemical effects of CAR in human serum samples. Dhcr7+/− and wild-type time-pregnant mice were exposed to vehicle or 0.2 mg/kg CAR from E12 to E19. Levels of CAR, CAR metabolites, sterols, and oxysterols were measured in the brain of maternally exposed offspring at various time points using LC-MS/MS. Embryonic exposure to CAR significantly increased levels of 7-DHC in all organs of exposed embryos, with a particularly strong effect in the brain. Detectable levels of CAR and elevated 7-DHC were observed in the brain of newborn pups 14 days after drug exposure. In addition, CAR altered sterol metabolism in all animals analyzed, with the strongest effect on the brain of Dhcr7+/− pups born to Dhcr7+/− dams. Furthermore, CAR elevated toxic oxysterols in the brain of maternally exposed Dhcr7+/− offspring to levels approaching those seen in a mouse model of Smith–Lemli–Opitz syndrome. Finally, we observed that patients taking CAR have elevated 7-DHC in their serum. In summary, maternal DHCR7 heterozygosity, combined with offspring DHCR7 heterozygosity might represent a vulnerability factor to medications that interfere with sterol biosynthesis. Due to the conserved sterol biosynthesis between mice and humans, we suggest that the 1–3% of patient population with single-allele DHCR7 mutations might not be ideal candidates for CAR use, especially if they are nursing, pregnant or plan to become pregnant.