bluuebunny/crossref_metadata_2025 huggingface dataset:
Pregnancy outcomes in women living with HIV and HIV‐negative women in South Africa: Cohort analysis based on bias‐corrected gestational age
Authors: Malaba Thokozile R. , Mukonda Elton , Matjila Mushi , Madlala Hlengiwe P. , Myer Landon , Newell Marie‐Louise ,   for the PIMS Study Group
Published: December 2021

Background

Antiretroviral therapy (ART) use during pregnancy may be associated with adverse outcomes, but findings have been inconsistent, at least in part due to unreliably estimated gestational age.

Objective

To quantify the association between HIV status, ART initiation timing and adverse birth outcomes, with reliably assessed gestational age at booking, in a public sector primary care facility in Cape Town, South Africa.

Methods

Pregnant women, HIV‐negative or living with HIV (WLHIV), were enrolled at first antenatal care visit and followed through delivery. Ultrasound‐assessed gestational age was deemed the gold standard. Based on quantitative bias analysis for outcome misclassification, gestational age by non‐ultrasound assessment was corrected using multiple overimputation, which deals with missing data and measurement error simultaneously. Using bias‐corrected gestational age, birth outcomes were compared between WLHIV and HIV‐negative women, and among WLHIV who initiated ART before versus during pregnancy, further divided into trimesters.

Results

Of 3952 women enrolled, 37% were WLHIV (mostly using tenofovir + emtricitabine + efavirenz). Last menstrual period (LMP)‐based gestational age was identified to be biased, and LMP measures were thus corrected using multiple overimputation. Comparing WLHIV and HIV‐negative women, adjusted risk ratio (aRR) of overall pregnancy loss was 1.26 (95% confidence interval [CI] 0.98, 1.61); aRR of preterm delivery was 1.02 (95% CI 0.88, 1.20); aRR of small for gestational age infants was 1.43 (95% CI 1.14, 1.80). Among WLHIV, outcomes were similar by ART initiation timing.

Conclusions

In this routine care cohort, risk of SGA, and possibly of pregnancy loss, was increased in WLHIV compared with HIV‐negative women, with no evidence of increased risk of preterm delivery. Further research is needed to improve mechanistic understanding of the contribution of ART to adverse birth outcomes to optimize treatment for pregnant WLHIV and ensure optimal maternal and infant outcomes.
Group B Streptococcus real‐time PCR may potentially reduce intrapartum maternal antibiotic treatment
Authors: Kugelman Nir , Kleifeld Shiran , Shaked‐Mishan Pninit , Assaf Wisam , Marom Inbal , Cohen Nadav , Gruber Maya , Lavie Ofer , Waisman Dan , Kedar Reuven , Bardicef Mordehai , Damti Amit
Published: December 2021

Background

Protocols for preventing early‐onset group B streptococcal (GBS) neonatal infection may result in unnecessary antibiotics administration. Real‐time polymerase chain reaction (PCR) can provide a result within 30–60 min and has been found to be specific and sensitive for defining intrapartum GBS status.

Objective

To evaluate whether implementation of GBS fast real‐time PCR to all women who require GBS prophylaxis may reduce the use of maternal prophylactic antibiotics.

Methods

This prospective cohort study included women admitted to a single delivery ward who required prophylactic antibiotics either due to a positive antepartum GBS culture screening performed at 35–37 weeks or due to an unknown GBS status with an intrapartum risk factor. All the women were tested by a double vaginal swab (real‐time PCR and culture) as soon as it became apparent, they required antibiotic prophylaxis and prior to its administration.

Results

Between May 2019 and August 2020, 303 women met eligibility criteria and were enrolled, but four were excluded from the analysis due to failed culture or PCR tests. Of 299 women included in the study, 208 (69.5%) and 180 (60.2%) women, showed no evidence of GBS on intrapartum culture or PCR, respectively. Of 89 GBS antepartum carriers, 43 (48.3%) and 32 (35.9%) had negative intrapartum culture and PCR results, respectively. Of the 210 women with risk factors, 165 (78.5%) were culture negative and 148 (70.4%) had a negative PCR. Using intrapartum culture as the gold standard, intrapartum GBS real‐time PCR was found to have a sensitivity of 97.8% (95% confidence interval [CI] 92.3, 99.7) and a specificity of 85.6% (95% CI 80.1, 90.1).

Conclusions

Compared with antepartum universal culture screening or intrapartum risk‐factor assessment, the need for maternal antibiotic treatment may be substantially reduced by implementation of intrapartum GBS real‐time PCR, without compromising the sensitivity of GBS detection.
Understanding the clinical characteristics of lesbian, gay, and bisexual military service members and adult beneficiaries within an inpatient psychiatric sample
Authors: Thompson Matthew F. , Luk Jeremy W. , LaCroix Jessica M. , Perera Kanchana U. , Goldston David B. , Weaver Jennifer J. , Soumoff Alyssa , Ghahramanlou‐Holloway Marjan
Published: December 2021

Background

Limited knowledge exists regarding targets for suicide‐focused care among high‐risk United States (U.S.) civilian and military sexual minorities.

Purpose

This study aimed to understand the demographic and clinical characteristics of a suicidal sexual minority sample, psychiatrically hospitalized in military treatment facilities, to advance future targeted care for this vulnerable subgroup.

Methods

Secondary analysis of baseline data from a multisite psychotherapy randomized controlled trial was performed comparing those who self‐identified as lesbian, gay, or bisexual (LGB; n = 39) to heterosexual participants (n = 170).

Results

LGB participants were more likely than heterosexual participants to be younger, female, never married, and enlisted rank. LGB participants reported significantly lower family support, higher perceived burdensomeness, lower acquired capability for suicide, and were twice as likely to report that they could not control their suicidal thoughts. LGB and heterosexual participants reported similar levels of other suicide risk indicators and similar lifetime suicidal ideation and attempt histories.

Conclusions

Compared to heterosexual participants, LGB participants reported increased risk indicators for suicide yet similar lifetime suicidal ideation and attempt histories. Suicide prevention programs should address the unique needs of this vulnerable subgroup. Interventions targeting family support, perceived burdensomeness, and controllability of suicidal thoughts may be promising.
Ash and biochar amendment of coarse sandy soil for growing crops under drought conditions
Authors: Bruun Esben W. , Müller‐Stöver Dorette , Pedersen Betina Nørgaard , Hansen Line Vinther , Petersen Carsten Tilbæk
Published: December 2021

Appropriate soil amendments may increase plant available water and crop yields on coarse sandy soils under drought conditions. In this study, we applied straw ash or straw biochar from gasification to a Danish coarse sandy subsoil to assess the effects on soil water retention, evapotranspiration and crop yields. Spring barley (2016, 2017) and winter wheat (2018) were grown over three years in columns containing 25cm of organic matter‐rich topsoil, 80 cm of amended coarse sandy soil (1.5%, 3%, 6% wt. ash or 1% wt. biochar or control soil) and 45 cm of un‐amended subsoil. Precipitation, evaporative demands and soil moisture were recorded across the growth seasons, with 2018 having severe drought conditions. This year evapotranspiration levels increased with increasing ash and biochar content (by 54% and 33% for the 6% ash‐ and 1% biochar‐amended soils, respectively), and plant dry matter increased by 18% in both the 1% biochar‐ and 6% ash‐treated soils compared to the untreated control. A linear relationship was established between in situ field capacity and ash dosage (R2 = .96), showing an increase of 2.2% per percentage (wt.) of ash added, while the 1% biochar treatment increased the capacity by 3.5%, indicating a higher efficiency than for ash. However, we did not find significant positive effects on grain yields. The results show that ash and biochar have the potential to significantly increase soil water retention, evapotranspiration and total dry matter yield in drought conditions, but that this may not correspond to an increase in grain yield.
The relationship between equine pastern dermatitis, meteorological factors, and the skin microbiota
Authors: Kaiser‐Thom Sarah , Hilty Markus , Ramseyer Alessandra , Epper Pascale , Gerber Vinzenz
Published: December 2021

Background

Equine pastern dermatitis (EPD) is a multifactorial syndrome, with prolonged exposure to moisture assumed to be a predisposing or primary factor.

Hypothesis/Objectives

To examine the course of EPD lesion severity, changes in bacterial skin microbiota, and the influence of meteorological factors.

Animals

Prospective, longitudinal cohort study over a one‐year period, with six Franches‐Montagnes stallions, four affected by EPD and two unaffected, that were kept under the same conditions.

Methods and materials

Pasterns were scored for lesion severity and sampled once a month for 12 consecutive months. Lesion severity, the skin microbiota and meteorological factors were examined for associations.

Results

EPD lesions tended to worsen in autumn and at the beginning of spring. The relationship between lesion severity and the meteorological factor precipitation was not clearly evident; high scores were preceded by both low or high rates of precipitation. Microbiota in affected pasterns appeared to have experienced a reduction in alpha diversity. Beta diversity analyses demonstrated that bacterial community structures were altered in affected versus unaffected pasterns, and that alterations were more pronounced with higher EPD scores (P = 0.005). Meteorological factors also had considerable influences on the bacterial composition, whereby these influences appeared to be more marked in the affected pasterns (P = 0.001, F = 3.19) than in unaffected ones (P = 0.005, F = 1.83).

Conclusions and clinical relevance

Our study provides preliminary observations of the relationships between lesion severity, meteorological factors and cutaneous bacteria. The population was too small to draw firm conclusions, and further studies on environmental factors and the involvement of bacteria in this multifactorial disease are needed.
Conceptualising Open Science in the 21st Century
Authors: Ashepet Mercy Gloria , Bossuyt Ignace , Brookhuis Hein , Constantin Cristian , Fedele Marta , Goel Naina , Pizzolato Daniel , Van Even Priscilla , Mendes Ana Barbosa , Snick Anne
Published: December 2021

Open Science that is adaptive to the complexity of the 21st century is emerging in transdisciplinary institutions outside of academia. Despite its growing popularity and plurality as a movement, the scope in which Open Science is practiced and discussed inside academia is still mostly
restricted to the scientific community and fragmented between disciplinary silos. Researchers and policymakers promoting Open Science often focus on knowledge translation and still recognise experts and academia as the main producers of knowledge, essentially closing the research process to
non-researchers and preventing other perspectives from being integrated into knowledge production. Our aim with this project was to adopt a systems perspective to understand how Open Science can address the challenges in the current knowledge production system. Open discussions among the team
members revealed distinct understandings of what constitutes Open Science. Thus, during our process we collated these many defi nitions of Open Science and extracted the dimensions that underlie such definitions and mapped how these dimensions could be interconnected in a more comprehensive
conceptualisation of Open Science. Future iterations of the challenge could build on our reflections and explore how these Open Science dimensions translate into scientific practice and how researchers can be encouraged to reflect on Open Science in a more systems-oriented way. Our findings
have been summarised in a small video.
Aliasing-free broadband direction of arrival estimation using a frequency-difference technique
Authors: Yang Long , Wang Yong , Yang Yixin
Published: December 2021

When the intersensor spacing of a uniform linear array (ULA) is larger than the half-wavelength of an incident narrowband signal, spatial aliasing is generated. For broadband signals, the broadband spatial spectrum is still affected as a result of the spatial aliasing in each frequency bin. In this paper, an aliasing-free broadband direction-of-arrival (DOA) estimation algorithm for ULAs is proposed. First, an array output is constructed with a given Gaussian random sequence from the direction ϑ. Then, a frequency-difference (FD) operation is conducted, which multiplies the array observation in the frequency bin f by the conjugate form of the constructed array output in the frequency bin f+Δf. Thus, an equivalent array output at a desired frequency Δf is obtained, whose wavelength is equal to twice the intersensor spacing. In this manner, an aliasing-free spatial spectrum in the FD domain is achieved. Scanning the direction ϑ, the DOA of signals is finally estimated based on the difference between the peaks in the aliasing-free spatial spectrum and direction ϑ. The proposed method can achieve a satisfactory estimation even in a strong interference environment. The simulations and experimental results are included to demonstrate the superiority of the proposed method.
Differences in Sport Management Doctoral Students’ Experiences With Gender Microaggressions and Stereotype Threat by Gender
Authors: Williams Sarah B. , Taylor Elizabeth A. , Christopher Greenwell T. , Burpo Brigitte M.
Published: December 2021

Not unlike the sport industry, the majority of sport management students in the United States are White, middle-class males. As women in male-dominated academic departments experience gender harassment more frequently than women in balanced or female-dominated departments, the purpose of this study was to explore the experiences of sport management doctoral students with gender microaggressions and stereotype threat by gender to examine if such experiences occur at this stage in academia. The results indicate that female students experience gender microaggressions of being excluded, being treated like a second-class citizen, and being placed in restrictive roles by program faculty due to their gender more frequently than male students. This study provides clarity into issues affecting female doctoral student progression postgraduation in sport management. In addition, this study provides context around the student experience in doctoral programs across male-dominated academic disciplines.
Frenkel biexcitons in hybrid HJ photophysical aggregates
Authors: Gutiérrez-Meza Elizabeth , Malatesta Ravyn , Li Hongmo , Bargigia Ilaria , Srimath Kandada Ajay Ram , Valverde-Chávez David A. , Kim Seong-Min , Li Hao , Stingelin Natalie , Tretiak Sergei , Bittner Eric R. , Silva-Acuña Carlos
Published: December 2021

Bound primary photoexcitation pairs are characterized in semiconductor polymers.
A biopolymer hydrogel electrostatically reinforced by amino-functionalized bioactive glass for accelerated bone regeneration
Authors: Ding Xinxin , Shi Junyu , Wei Jianxu , Li Yuan , Wu Xiangbing , Zhang Yi , Jiang Xue , Zhang Xiaomeng , Lai Hongchang
Published: December 2021

A hydrogel with improved interfacial compatibility was formed to promote osteogenesis by establishing electrostatic bonds.
Regulation of myelination by microglia
Authors: Santos Erin N. , Fields R. Douglas
Published: December 2021

Healthy white matter development requires microglial modification of oligodendrocyte populations and myelin membrane.
Organic neuromorphic electronics for sensorimotor integration and learning in robotics
Authors: Krauhausen Imke , Koutsouras Dimitrios A. , Melianas Armantas , Keene Scott T. , Lieberth Katharina , Ledanseur Hadrien , Sheelamanthula Rajendar , Giovannitti Alexander , Torricelli Fabrizio , Mcculloch Iain , Blom Paul W. M. , Salleo Alberto , van de Burgt Yoeri , Gkoupidenis Paschalis
Published: December 2021

A robot learns to follow a path to exit a maze through sensorimotor learning that is induced by an organic neuromorphic circuit.
Stressing the personal benefits of the covid-19 vaccine might encourage more people to accept it
Authors: Saul Helen , Gursul Deniz
Published: December 2021

The study

Freeman D, Loe BS, Yu LM, et al. Effects of different types of written vaccination information on COVID-19 vaccine hesitancy in the UK (OCEANS-III): a single-blind, parallel-group, randomised controlled trial.Lancet Public Health2021;6:416-27.

To read the full NIHR Alert, go to:https://evidence.nihr.ac.uk/alert/stressing-personal-benefits-of-covid-vaccine-could-reduce-hesitancy
Artificial intelligence and inflammatory bowel disease: practicalities and future prospects
Authors: Brooks-Warburton Johanne , Ashton James , Dhar Anjan , Tham Tony , Allen Patrick B , Hoque Sami , Lovat Laurence B , Sebastian Shaji
Published: December 2021

Artificial intelligence (AI) is an emerging technology predicted to have significant applications in healthcare. This review highlights AI applications that impact the patient journey in inflammatory bowel disease (IBD), from genomics to endoscopic applications in disease classification, stratification and self-monitoring to risk stratification for personalised management. We discuss the practical AI applications currently in use while giving a balanced view of concerns and pitfalls and look to the future with the potential of where AI can provide significant value to the care of the patient with IBD.
New bright soliton solutions for Kadomtsev–Petviashvili–Benjamin–Bona–Mahony equations and bidirectional propagation of water wave surface
Authors: Saha Ray S. , Singh Shailendra
Published: December 2021

The governing equations for fluid flows, i.e. Kadomtsev–Petviashvili–Benjamin–Bona–Mahony (KP-BBM) model equations represent a water wave model. These model equations describe the bidirectional propagating water wave surface. In this paper, an auto-Bäcklund transformation is being generated by utilizing truncated Painlevé expansion method for the considered equation. This paper determines the new bright soliton solutions for [Formula: see text] and [Formula: see text]-dimensional nonlinear KP-BBM equations. The simplified version of Hirota’s technique is utilized to infer new bright soliton solutions. The results are plotted graphically to understand the physical behavior of solutions.
Nonlinear dynamical study to time fractional Dullian–Gottwald–Holm model of shallow water waves
Authors: Younis M. , Seadawy Aly R. , Sikandar I. , Baber M. Z. , Ahmed N. , Rizvi S. T. R. , Althobaiti Saad
Published: December 2021

This paper studies the exact traveling wave solutions to the nonlinear Dullin–Gottwald–Holm model which has the application in shallow-water waves in which the fractional derivative is considered in the sense of conformable derivative. Diverse exact solutions in hyperbolic, trigonometric and plane wave forms are obtained using two integration norms. For this purpose [Formula: see text]-expansion method and reccati mapping techniques are used. The 3D plots and their corresponding contour graphs are also depicted. Being concise and straightforward, the calculations demonstrate the effectiveness and convenience of the method for solving other nonlinear partial differential equations.
G-family polynomials
Authors: Brown Madeline , Nelson Sam
Published: December 2021

We introduce two notions of quandle polynomials for [Formula: see text]-families of quandles: the quandle polynomial of the associated quandle and a [Formula: see text]-family polynomial with coefficients in the group ring of [Formula: see text]. As an application we define image subquandle polynomial enhancements of the [Formula: see text]-family counting invariant for trivalent spatial graphs and handlebody-links. We provide examples to show that the new enhancements are proper.
MODELING LIFETIME EXPECTED CREDIT LOSSES ON BANK LOANS
Authors: CHELLATHURAI THAMAYANTHI
Published: December 2021

The guidelines of various Accounting Standards require every financial institution to measure lifetime expected credit losses (LECLs) on every instrument, and to determine at each reporting date if there has been a significant increase in credit risk since its inception. This paper models LECLs on bank loans given to a firm that has promised to repay debt at multiple points over the lifetime of the contract. The LECL can be written as a sum of ECLs (estimated at reporting date) incurred at debt repayment times. The ECL at any debt repayment time can be written as a product of the probability of default (PD), the expected value of loss given default and the exposure at default. We derive a stochastic dynamical equation for the value of the firm’s asset by incorporating the dynamics of the factors. Also, we show how the LECL and the term structure of the PD can be estimated by solving a Black–Scholes–Merton like partial differential equation. As an illustration, we present the numerical results for the various credit loss indicators of a fictitious firm when the dynamics of the short-term interest rate is characterized by a Cox–Ingersoll–Ross mean-reverting process.
The domination monoid in o-minimal theories
Authors: Mennuni Rosario
Published: December 2021

We study the monoid of global invariant types modulo domination-equivalence in the context of o-minimal theories. We reduce its computation to the problem of proving that it is generated by classes of 1-types. We show this to hold in Real Closed Fields, where generators of this monoid correspond to invariant convex subrings of the monster model. Combined with [C. Ealy, D. Haskell and J. Maríková, Residue field domination in real closed valued fields, Notre Dame J. Formal Logic 60(3) (2019) 333–351], this allows us to compute the domination monoid in the weakly o-minimal theory of Real Closed Valued Fields.
Normalized solutions to a Schrödinger–Bopp–Podolsky system under Neumann boundary conditions
Authors: Afonso Danilo G. , Siciliano Gaetano
Published: December 2021

In this paper, we study a Schrödinger–Bopp–Podolsky (SBP) system of partial differential equations in a bounded and smooth domain of [Formula: see text] with a nonconstant coupling factor. Under a compatibility condition on the boundary data we deduce existence of solutions by means of the Ljusternik–Schnirelmann theory.
A State-of-the-Art Review on FRF-Based Structural Damage Detection: Development in Last Two Decades and Way Forward
Authors: Das Saranika , Roy Koushik
Published: December 2021

Vibration-based damage detection techniques receive wide attention of the research community in recent years to overcome the limitations of conventional structural health monitoring methods. The modal parameters, namely, natural frequencies, mode shapes, transmissibility, frequency response function (FRF), and other damage sensitive features are usually employed to identify damage in a structure. The main objective of this review is to generate a detailed understanding of FRF-based techniques and to study their performance in terms of advantage, accuracy, and limitations in structural damage detection. This paper also reviews various approaches to develop methodologies in terms of efficiency and computational time. The study observed that excitation frequency, location of application of excitation, type of sensor, number of measurement locations, noise contamination in FRF data, selection of frequency range for simulation, weighting and numerical techniques to solve the over-determined set of equations influence the effectiveness of damage identification procedure. Limitations and future prospects have also been addressed in this paper. The content of this paper aims to guide researchers in developing formulations, updating models, and improving results in the field of FRF-based damage identification.
The second moment of Sn(t) on the Riemann hypothesis
Authors: Chirre Andrés , Quesada-Herrera Oscar E.
Published: December 2021

Let [Formula: see text] be the argument of the Riemann zeta-function at the point [Formula: see text]. For [Formula: see text] and [Formula: see text] define its antiderivatives as [Formula: see text] where [Formula: see text] is a specific constant depending on [Formula: see text] and [Formula: see text]. In 1925, Littlewood proved, under the Riemann Hypothesis (RH), that [Formula: see text] for [Formula: see text]. In 1946, Selberg unconditionally established the explicit asymptotic formulas for the second moments of [Formula: see text] and [Formula: see text]. This was extended by Fujii for [Formula: see text], when [Formula: see text]. Assuming the RH, we give the explicit asymptotic formula for the second moment of [Formula: see text] up to the second-order term, for [Formula: see text]. Our result conditionally refines Selberg’s and Fujii’s formulas and extends previous work by Goldston in [Formula: see text], where the case [Formula: see text] was considered.
Experimental Performance Analysis of R1234yf in an Air-Conditioning System as Substitute of R134a
Authors: Medany M. M. , Morsi M. El , El-Sayed A. R.
Published: December 2021

In this work, R1234yf is tested in an air-conditioning system as a proposed alternative to R134a. The system is tested at 30, 35, 40, 45 and 50[Formula: see text]Hz evaporator fan frequency to cool the air entering into the evaporator section at a fixed temperature of 35∘C. The system is charged with 600, 700, 800, 1000 and 1200[Formula: see text]g of each refrigerant. The charge mass of 800 grams gives the best performance for both refrigerants. Also, R1234yf has higher COP, exergetic efficiency, second law efficiency, and lower compressor power consumption. Both refrigerants operate at a moderate range of compressor discharge temperature of 85∘C.
A Geometric Complementarity-Based Tool for Protein–Protein Docking
Authors: Sunny Sharon , Jayaraj P. B.
Published: December 2021

The computationally hard protein–protein complex structure prediction problem is continuously fascinating to the scientific community due to its biological impact. The field has witnessed the application of geometric algorithms, randomized algorithms, and evolutionary algorithms to name a few. These techniques improve either the searching or scoring phase. An effective searching strategy does not generate a large conformation space that perhaps demands computational power. Another determining factor is the parameter chosen for score calculation. The proposed method is an attempt to curtail the conformations by limiting the search procedure to probable regions. In this method, partial derivatives are calculated on the coarse-grained representation of the surface residues to identify the optimal points on the protein surface. Contrary to the existing geometric-based algorithms that align the convex and concave regions of both proteins, this method aligns the concave regions of the receptor with convex regions of the ligand only and thus reduces the size of conformation space. The method’s performance is evaluated using the 55 newly added targets in Protein–Protein Docking Benchmark v 5 and is found to be successful for around 47% of the targets.
Spatial-temporal motion control via composite cam-follower mechanisms
Authors: Cheng Yingjie , Sun Yucheng , Song Peng , Liu Ligang
Published: December 2021

Motion control, both on the trajectory and timing, is crucial for mechanical automata to perform functionalities such as walking and entertaining. We present
composite cam-follower mechanisms
that can control their spatial-temporal motions to exactly follow trajectories and timings specified by users, and propose a computational technique to model, design, and optimize these mechanisms. The building blocks of our mechanisms are a new kind of cam-follower mechanism with a modified joint, in which the follower can perform spatial motion on a planar, cylindrical, or spherical surface controlled by the 3D cam's profile. We parameterize the geometry of these cam-follower mechanisms, formulate analytical equations to model their kinematics and dynamics, and present a method to combine multiple cam-follower mechanisms into a working mechanism. Taking this modeling as a foundation, we propose a computational approach to designing and optimizing the geometry and layout of composite cam-follower mechanisms, with an objective of performing target spatial-temporal motions driving by a small motor torque. We demonstrate the effectiveness of our technique by designing different kinds of personalized automata and showing results not attainable by conventional mechanisms.
HyperNeRF
Authors: Park Keunhong , Sinha Utkarsh , Hedman Peter , Barron Jonathan T. , Bouaziz Sofien , Goldman Dan B , Martin-Brualla Ricardo , Seitz Steven M.
Published: December 2021

Neural Radiance Fields (NeRF) are able to reconstruct scenes with unprecedented fidelity, and various recent works have extended NeRF to handle dynamic scenes. A common approach to reconstruct such non-rigid scenes is through the use of a learned deformation field mapping from coordinates in each input image into a canonical template coordinate space. However, these deformation-based approaches struggle to model changes in topology, as topological changes require a discontinuity in the deformation field, but these deformation fields are necessarily continuous. We address this limitation by lifting NeRFs into a higher dimensional space, and by representing the 5D radiance field corresponding to each individual input image as a slice through this "hyper-space". Our method is inspired by level set methods, which model the evolution of surfaces as slices through a higher dimensional surface. We evaluate our method on two tasks: (i) interpolating smoothly between "moments", i.e., configurations of the scene, seen in the input images while maintaining visual plausibility, and (ii) novel-view synthesis at fixed moments. We show that our method, which we dub
HyperNeRF
, outperforms existing methods on both tasks. Compared to Nerfies, HyperNeRF reduces average error rates by 4.1% for interpolation and 8.6% for novel-view synthesis, as measured by LPIPS. Additional videos, results, and visualizations are available at hypernerf.github.io.
Intuitive and efficient roof modeling for reconstruction and synthesis
Authors: Ren Jing , Zhang Biao , Wu Bojian , Huang Jianqiang , Fan Lubin , Ovsjanikov Maks , Wonka Peter
Published: December 2021

We propose a novel and flexible roof modeling approach that can be used for constructing planar 3D polygon roof meshes. Our method uses a graph structure to encode roof topology and enforces the roof validity by optimizing a simple but effective planarity metric we propose. This approach is significantly more efficient than using general purpose 3D modeling tools such as 3ds Max or SketchUp, and more powerful and expressive than specialized tools such as the straight skeleton. Our optimization-based formulation is also flexible and can accommodate different styles and user preferences for roof modeling. We showcase two applications. The first application is an interactive roof editing framework that can be used for roof design or roof reconstruction from aerial images. We highlight the efficiency and generality of our approach by constructing a mesh-image paired dataset consisting of 2539 roofs. Our second application is a generative model to synthesize new roof meshes from scratch. We use our novel dataset to combine machine learning and our roof optimization techniques, by using transformers and graph convolutional networks to model roof topology, and our roof optimization methods to enforce the planarity constraint.
Ships, splashes, and waves on a vast ocean
Authors: Huang Libo , Qu Ziyin , Tan Xun , Zhang Xinxin , Michels Dominik L. , Jiang Chenfanfu
Published: December 2021

The simulation of large open water surface is challenging using a uniform volumetric discretization of the Navier-Stokes equations. Simulating water splashes near moving objects, which height field methods for water waves cannot capture, necessitates high resolutions. Such simulations can be carried out using the Fluid-Implicit-Particle (FLIP) method. However, the FLIP method is not efficient for the long-lasting water waves that propagate to long distances, which require sufficient depth for a correct dispersion relationship. This paper presents a new method to tackle this dilemma through an efficient hybridization of volumetric and surface-based advection-projection discretizations. We design a hybrid time-stepping algorithm that combines a FLIP domain and an adaptively remeshed Boundary Element Method (BEM) domain for the incompressible Euler equations. The resulting framework captures the detailed water splashes near moving objects with the FLIP method, and produces convincing water waves with correct dispersion relationships at modest additional costs.
Differentiable transient rendering
Authors: Yi Shinyoung , Kim Donggun , Choi Kiseok , Jarabo Adrian , Gutierrez Diego , Kim Min H.
Published: December 2021

Recent differentiable rendering techniques have become key tools to tackle many inverse problems in graphics and vision. Existing models, however, assume steady-state light transport, i.e., infinite speed of light. While this is a safe assumption for many applications, recent advances in ultrafast imaging leverage the wealth of information that can be extracted from the exact time of flight of light. In this context, physically-based transient rendering allows to efficiently simulate and analyze light transport considering that the speed of light is indeed finite. In this paper, we introduce a novel differentiable transient rendering framework, to help bring the potential of differentiable approaches into the transient regime. To differentiate the transient path integral we need to take into account that scattering events at path vertices are no longer independent; instead, tracking the time of flight of light requires treating such scattering events at path vertices jointly as a multidimensional, evolving manifold. We thus turn to the generalized transport theorem, and introduce a novel
correlated importance
term, which links the time-integrated contribution of a path to its light throughput, and allows us to handle discontinuities in the light and sensor functions. Last, we present results in several challenging scenarios where the time of flight of light plays an important role such as optimizing indices of refraction, non-line-of-sight tracking with nonplanar relay walls, and non-line-of-sight tracking around two corners.
Fast volume rendering with spatiotemporal reservoir resampling
Authors: Lin Daqi , Wyman Chris , Yuksel Cem
Published: December 2021

Volume rendering under complex, dynamic lighting is challenging, especially if targeting real-time. To address this challenge, we extend a recent direct illumination sampling technique, spatiotemporal reservoir resampling, to multi-dimensional path space for volumetric media.

By fully evaluating just a single path sample per pixel, our volumetric path tracer shows unprecedented convergence. To achieve this, we properly estimate the chosen sample's probability via approximate perfect importance sampling with spatiotemporal resampling. A key observation is recognizing that applying cheaper, biased techniques to approximate scattering along candidate paths (during resampling) does not add bias when shading. This allows us to combine transmittance evaluation techniques: cheap approximations where evaluations must occur many times for reuse, and unbiased methods for final, per-pixel evaluation.

With this reformulation, we achieve low-noise, interactive volumetric path tracing with arbitrary dynamic lighting, including volumetric emission, and maintain interactive performance even on high-resolution volumes. When paired with denoising, our low-noise sampling helps preserve smaller-scale volumetric details.
Human dynamics from monocular video with dynamic camera movements
Authors: Yu Ri , Park Hwangpil , Lee Jehee
Published: December 2021

We propose a new method that reconstructs 3D human motion from in-the-wild video by making full use of prior knowledge on the laws of physics. Previous studies focus on reconstructing joint angles and positions in the body local coordinate frame. Body translations and rotations in the global reference frame are partially reconstructed only when the video has a static camera view. We are interested in overcoming this static view limitation to deal with dynamic view videos. The camera may pan, tilt, and zoom to track the moving subject. Since we do not assume any limitations on camera movements, body translations and rotations from the video do not correspond to absolute positions in the reference frame. The key technical challenge is inferring body translations and rotations from a sequence of 3D full-body poses, assuming the absence of root motion. This inference is possible because human motion obeys the law of physics. Our reconstruction algorithm produces a control policy that simulates 3D human motion imitating the one in the video. Our algorithm is particularly useful for reconstructing highly dynamic movements, such as sports, dance, gymnastics, and parkour actions.
Rendering with style
Authors: Chandran Prashanth , Winberg Sebastian , Zoss Gaspard , Riviere Jérémy , Gross Markus , Gotardo Paulo , Bradley Derek
Published: December 2021

For several decades, researchers have been advancing techniques for creating and rendering 3D digital faces, where a lot of the effort has gone into geometry and appearance capture, modeling and rendering techniques. This body of research work has largely focused on facial skin, with much less attention devoted to peripheral components like hair, eyes and the interior of the mouth. As a result, even with the best technology for facial capture and rendering, in most high-end productions a lot of artist time is still spent modeling the missing components and fine-tuning the rendering parameters to combine everything into photo-real digital renders. In this work we propose to combine incomplete, high-quality renderings showing only facial skin with recent methods for neural rendering of faces, in order to automatically and seamlessly create photo-realistic full-head portrait renders from captured data without the need for artist intervention. Our method begins with traditional face rendering, where the skin is rendered with the desired appearance, expression, viewpoint, and illumination. These skin renders are then projected into the latent space of a pre-trained neural network that can generate arbitrary photo-real face images (StyleGAN2). The result is a sequence of realistic face images that match the identity and appearance of the 3D character at the skin level, but is completed naturally with synthesized hair, eyes, inner mouth and surroundings. Notably, we present the first method for
multi-frame consistent
projection into this latent space, allowing photo-realistic rendering and preservation of the identity of the digital human over an animated performance sequence, which can depict different expressions, lighting conditions and viewpoints. Our method can be used in new face rendering pipelines and, importantly, in other deep learning applications that require large amounts of realistic training data with ground-truth 3D geometry, appearance maps, lighting, and viewpoint.
Physical light-matter interaction in hermite-gauss space
Authors: Steinberg Shlomi , Yan Ling-Qi
Published: December 2021

Our purpose in this paper is two-fold: introduce a computationally-tractable decomposition of the coherence properties of light; and, present a general-purpose light-matter interaction framework for partially-coherent light. In a recent publication, Steinberg and Yan [2021] introduced a framework that generalises the classical radiometry-based light transport to physical optics. This facilitates a qualitative increase in the scope of optical phenomena that can be rendered, however with the additional expressibility comes greater analytic difficulty: This coherence of light, which is the core quantity of physical light transport, depends initially on the characteristics of the light source, and mutates on interaction with matter and propagation. Furthermore, current tools that aim to quantify the interaction of partially-coherent light with matter remain limited to specific materials and are computationally intensive. To practically represent a wide class of coherence functions, we decompose their modal content in Hermite-Gauss space and derive a set of light-matter interaction formulae, which quantify how matter scatters light and affects its coherence properties. Then, we model matter as a locally-stationary random process, generalizing the prevalent deterministic and stationary stochastic descriptions. This gives rise to a framework that is able to formulate the interaction of arbitrary partially-coherent light with a wide class of matter. Indeed, we will show that our presented formalism unifies a few of the state-of-the-art scatter and diffraction formulae into one cohesive theory. This formulae include the sourcing of partially-coherent light, scatter by rough surfaces and microgeometry, diffraction grating and interference by a layered structure.
A material point method for nonlinearly magnetized materials
Authors: Sun Yuchen , Ni Xingyu , Zhu Bo , Wang Bin , Chen Baoquan
Published: December 2021

We propose a novel numerical scheme to simulate interactions between a magnetic field and nonlinearly magnetized objects immersed in it. Under our nonlinear magnetization framework, the strength of magnetic forces is effectively saturated to produce stable simulations without requiring any parameter tuning. The mathematical model of our approach is based upon Langevin's nonlinear theory of paramagnetism, which bridges microscopic structures and macroscopic equations after a statistical derivation. We devise a hybrid Eulerian-Lagrangian numerical approach to simulating this strongly nonlinear process by leveraging the discrete material points to transfer both material properties and the number density of magnetic micro-particles in the simulation domain. The magnetic equations can then be built and solved efficiently on a background Cartesian grid, followed by a finite difference method to incorporate magnetic forces. The multi-scale coupling can be processed naturally by employing the established particle-grid interpolation schemes in a conventional MLS-MPM framework. We demonstrate the efficacy of our approach with a host of simulation examples governed by magnetic-mechanical coupling effects, ranging from magnetic deformable bodies to magnetic viscous fluids with nonlinear elastic constitutive laws.
Police Violence and Public Health
Authors: DeVylder Jordan E. , Anglin Deidre M. , Bowleg Lisa , Fedina Lisa , Link Bruce G.
Published: December 2021

Despite their enormous potential impact on population health and health inequities, police violence and use of excessive force have only recently been addressed from a public health perspective. Moving to change this state of affairs, this article considers police violence in the USA within a social determinants and health disparities framework, highlighting recent literature linking this exposure to mental health symptoms, physical health conditions, and premature mortality. The review demonstrates that police violence is common in the USA; is disproportionately directed toward Black, Latinx, and other marginalized communities; and exerts a significant and adverse effect on a broad range of health outcomes. The state-sponsored nature of police violence, its embedding within a historical and contemporary context of structural racism, and the unique circumstances of the exposure itself make it an especially salient and impactful form of violence exposure, both overlapping with and distinct from other forms of violence. We conclude by noting potential solutions that clinical psychology and allied fields may offer toalleviate the impact of police violence, while simultaneously recognizing that a true solution to this issue requires a drastic reformation or replacement of the criminal justice system, as well as addressing the broader context of structural and systemic racism in the USA.
Progesterone-dependent and progesterone-independent modulation of luminal epithelial transcription to support pregnancy in cattle
Authors: Martins Thiago , Sponchiado Mariana , Silva Felipe A. C. C. , Estrada-Cortés Eliab , Hansen Peter J. , Peñagaricano Francisco , Binelli Mario
Published: December 2021

In cattle, starting 4–5 days after estrus, preimplantation embryonic development occurs in the confinement of the uterine lumen. Cells in the endometrial epithelial layer control the molecular traffic to and from the lumen and, thereby determine luminal composition. Starting early postestrus, endometrial function is regulated by sex steroids, but the effects of progesterone on luminal cells transcription have not been measured in vivo. The first objective was to determine the extent to which progesterone controls transcription in luminal epithelial cells 4 days (D4) after estrus. The second objective was to discover luminal transcripts that predict pregnancy outcomes when the effect of progesterone is controlled. Endometrial luminal epithelial cells were collected from embryo transfer recipients on D4 using a cytological brush and their transcriptome was determined by RNASeq. Pregnancy by embryo transfer was measured on D30 (25 pregnant and 18 nonpregnant). Progesterone concentration on D4 was associated positively ( n = 182) and negatively ( n = 58) with gene expression. Progesterone-modulated transcription indicated an increase in oxidative phosphorylation, biosynthetic activity, and proliferation of epithelial cells. When these effects of progesterone were controlled, different genes affected positively ( n = 22) and negatively ( n = 292) odds of pregnancy. These set of genes indicated that a receptive uterine environment was characterized by the inhibition of phosphoinositide signaling and innate immune system responses. A panel of 25 genes predicted the pregnancy outcome with sensitivity and specificity ranging from 64%–96% and 44%–83%, respectively. In conclusion, in the early diestrus, both progesterone-dependent and progesterone-independent mechanisms regulate luminal epithelial transcription associated with pregnancy outcomes in cattle.