bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence of childhood mental disorders in high-income countries: a systematic review and meta-analysis to inform policymaking
Authors: Barican Jenny Lou , Yung Donna , Schwartz Christine , Zheng Yufei , Georgiades Katholiki , Waddell Charlotte
Published: July 2021

Question

Mental disorders typically start in childhood and persist, causing high individual and collective burdens. To inform policymaking to address children’s mental health in high-income countries we aimed to identify updated data on disorder prevalence.

Methods

We identified epidemiological studies reporting mental disorder prevalence in representative samples of children aged 18 years or younger—including a range of disorders and ages and assessing impairment (searching January 1990 through February 2021). We extracted associated service-use data where studies assessed this. We conducted meta-analyses using a random effects logistic model (using R metafor package).

Findings

Fourteen studies in 11 countries met inclusion criteria, published from 2003 to 2020 with a pooled sample of 61 545 children aged 4–18 years, including eight reporting service use. (All data were collected pre-COVID-19.) Overall prevalence of any childhood mental disorder was 12.7% (95% CI 10.1% to 15.9%; I2=99.1%). Significant heterogeneity pertained to diagnostic measurement and study location. Anxiety (5.2%), attention-deficit/hyperactivity (3.7%), oppositional defiant (3.3%), substance use (2.3%), conduct (1.3%) and depressive (1.3%) disorders were the most common. Among children with mental disorders, only 44.2% (95% CI 37.6% to 50.9%) received any services for these conditions.

Conclusions

An estimated one in eight children have mental disorders at any given time, causing symptoms and impairment, therefore requiring treatment. Yet even in high-income countries, most children with mental disorders are not receiving services for these conditions. We discuss the implications, particularly the need to substantially increase public investments in effective interventions. We also discuss the policy urgency, given the emerging increases in childhood mental health problems since the onset of the COVID-19 pandemic (PROSPERO CRD42020157262).
BET 1: The Ottawa Subarachnoid Hemorrhage Clinical Decision Rule shows high sensitivity but limited evidence of patient benefit
Authors: Law Dorothy , Hirst Robert , Horner Daniel
Published: July 2021

A short-cut review of the literature was carried out to examine the diagnostic test characteristics and potential patient benefits through the use of the Ottawa Subarachnoid Haemorrhage Clinical Decision Rule. Nine papers were identified as suitable for inclusion using the reported search strategy. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of the best papers are tabulated. It is concluded that the Ottawa Clinical Decision Rule has a high sensitivity for the diagnosis of subarachnoid haemorrhage; however, there is limited robust evidence of international generalisability and no evidence of improved patient outcomes following implementation. Further prospective research is required in populations with variable prevalence to evaluate the safety and effectiveness of this intervention, compared with routine evaluation strategies.
Next-generation sequencing of bile cell-free DNA for the early detection of patients with malignant biliary strictures
Authors: Arechederra Maria , Rullán María , Amat Irene , Oyon Daniel , Zabalza Lucia , Elizalde Maria , Latasa M Ujue , Mercado Maria R , Ruiz-Clavijo David , Saldaña Cristina , Fernández-Urién Ignacio , Carrascosa Juan , Jusué Vanesa , Guerrero-Setas David , Zazpe Cruz , González-Borja Iranzu , Sangro Bruno , Herranz Jose M , Purroy Ana , Gil Isabel , Nelson Leonard J , Vila Juan J , Krawczyk Marcin , Zieniewicz Krzysztof , Patkowski Waldemar , Milkiewicz Piotr , Cubero Francisco Javier , Alkorta-Aranburu Gorka , G Fernandez-Barrena Maite , Urman Jesus M , Berasain Carmen , Avila Matias A
Published: July 2021

Objective

Despite significant progresses in imaging and pathological evaluation, early differentiation between benign and malignant biliary strictures remains challenging. Endoscopic retrograde cholangiopancreatography (ERCP) is used to investigate biliary strictures, enabling the collection of bile. We tested the diagnostic potential of next-generation sequencing (NGS) mutational analysis of bile cell-free DNA (cfDNA).

Design

A prospective cohort of patients with suspicious biliary strictures (n=68) was studied. The performance of initial pathological diagnosis was compared with that of the mutational analysis of bile cfDNA collected at the time of first ERCP using an NGS panel open to clinical laboratory implementation, the Oncomine Pan-Cancer Cell-Free assay.

Results

An initial pathological diagnosis classified these strictures as of benign (n=26), indeterminate (n=9) or malignant (n=33) origin. Sensitivity and specificity of this diagnosis were 60% and 100%, respectively, as on follow-up 14 of the 26 and eight of the nine initially benign or indeterminate strictures resulted malignant. Sensitivity and specificity for malignancy of our NGS assay, herein named Bilemut, were 96.4% and 69.2%, respectively. Importantly, one of the four Bilemut false positives developed pancreatic cancer after extended follow-up. Remarkably, the sensitivity for malignancy of Bilemut was 100% in patients with an initial diagnosis of benign or indeterminate strictures. Analysis of 30 paired bile and tissue samples also demonstrated the superior performance of Bilemut.

Conclusion

Implementation of Bilemut at the initial diagnostic stage for biliary strictures can significantly improve detection of malignancy, reduce delays in the clinical management of patients and assist in selecting patients for targeted therapies.
Effect of whole-body resistance training at different load intensities on circulating inflammatory biomarkers, body fat, muscular strength, and physical performance in postmenopausal women
Authors: Carneiro Marcelo A.S. , Oliveira Júnior Gersiel N. de , de Sousa Jairo F.R. , Orsatti Claudio L. , Murta Eddie F.C. , Michelin Márcia A. , Cyrino Edilson S. , Orsatti Fábio L.
Published: July 2021

The primary purpose of this study was to identify the impact of whole-body resistance training (RT) at different load intensities on adipokines, adhesion molecules, and extracellular heat shock proteins in postmenopausal women. As secondary purpose, we analyzed the impact of RT at different load intensities on body fat, muscular strength, and physical performance. Forty participants were randomized into lower-load intensity RT (LIRT, n = 20, 30–35 repetition maximum in the first set of each exercise) or higher-load intensity RT (HIRT, n = 20, 8–12 repetition maximum in the first set of each exercise). Adipokines (adiponectin and leptin), adhesion molecules (MCP-1 and ICAM-1), extracellular heat shock proteins (HO-1 and eHSP60), body fat, muscular strength (1RM), and physical performance [400-meter walking test (400-M) and 6-minute walking test (6MWT)] were analyzed at baseline and after 12-weeks RT. There was a significant time-by-group interaction for eHSP60 (P = 0.049) and 400-M (P = 0.003), indicating superiority of HIRT (d = 0.47 and 0.55). However, both groups similarly improved adiponectin, ICAM-1, HO-1, body fat, 1RM, and 6MWT (P < 0.05). Our study suggests that load intensity does not seem to determine the RT effect on several obesity-related pro-inflammatory and chemotactic compounds, body fat, 1RM, and 6MWT in postmenopausal women, although a greater improvement has been revealed for eHSP60 and 400-M in HIRT.

Novelty: Higher-load intensity resistance training improves eHSP60 and 400-M in postmenopausal women. Resistance training improves the inflammatory profile, body fat, muscle strength, and 6MWT, regardless of load intensity.
Dlx5promotes cancer progression through regulation ofCCND1in oral squamous cell carcinoma (OSCC)
Authors: Zhang Jianfei , Wu Jinyang , Chen Yang , Zhang Wenbin
Published: July 2021

Genetic studies have revealed a critical role of the distal-less homeobox gene 5 (Dlx5) in the pathogenesis of ovarian cancer, lung cancer, and T-cell lymphoma; however, the role and underlying mechanisms of Dlx5 in oral squamous cell carcinoma (OSCC) are largely unknown. In this study, we demonstrated that Dlx5 is up-regulated in OSCC tissues and cell lines, compared with their control groups. The results from our immunohistochemistry (IHC) analyses show that high expression levels of Dlx5 correlated with advanced TNM stages (P = 0.0001), lymph node metastasis (P = 0.0049), poor cellular differentiation (P = 0.0491), location of the tumors (P = 0.0132), and poor prognosis for the patient. We also demonstrated that knockdown of Dlx5 inhibited the viability, proliferation, and colony formation of OSCC cell lines CAL-27 and WSU-HN6 cells, probably by blocking cell cycle in the G1 phase. Furthermore, we revealed that Dlx5 exerts its biological functions via direct regulation of CCND1 in CAL-27 and WSU-HN6 cells. Ultimately, we have demonstrated that silencing of Dlx5 inhibits the growth of xenograft tumors in vivo, and that Dlx5 affects the progression of OSCC both in vitro and in vivo via directly regulating CCND1, providing a potential diagnostic biomarker and therapeutic target for OSCC.
Evaluation of design methods for side-resistance-only rock-socketed piles
Authors: Johnston Ian W.
Published: July 2021

The ability of three methods to predict the load–settlement response of rock-socketed piles was examined in a recent paper. The piles considered were complete piles in which both the side and base of the piles contribute to the total resistance. For a range of reasons, it is sometimes necessary to consider rock-socketed piles for which the resistance is provided only by the side of the socket. This paper extends the earlier paper by comparing predictions for side-resistance-only piles with the load–settlement response of a suite of full-scale side-resistance-only pile tests. Only two of the methods of the earlier paper are used for this comparison, as the third method could not decouple the two components of resistance. It is demonstrated that one of the methods produces reasonable predictions of performance, whereas the other appears to underpredict performance.
Effect of oregano oil and cranberry pulp supplementation in finishing pigs on the physicochemical quality of fresh loin during storage
Authors: Fortier M.P. , Guay F. , Saucier L.
Published: July 2021

Oregano oil and cranberry pulp supplements were added to the diets of finishing pigs to determine their effects on the meat quality of fresh loins during storage. Two and three levels of oregano oil (250 and 500 mg·kg−1) and cranberry pulp (5, 10, and 20 g·kg−1) were tested, according to a factorial experimental design. The loin meat was vacuum packed and analyzed at 0 (after the 24 h chilling period post slaughter), 23, 45, and 60 d of storage. Samples were repackaged under aerobic conditions after 0 or 23 d and analyzed after 4, 8, and 12 d. Oregano and cranberry supplements did not affect lipid oxidation (microgram of malondialdehyde equivalent per kilogram of meat) during anaerobic or aerobic storage. On day 0, the fatty acid profile of the loin samples demonstrated that the addition of cranberries at a dose of 10 g·kg−1 was associated with a lower percentage of saturated fatty acids (P = 0.04; 42.97% vs. 40.99%) and a trend for a higher percentage of monounsaturated fatty acids (P = 0.06; 47.26% vs. 46.09%). Considering the result obtained, feeding pigs with oregano and cranberry supplements had a limited effect on meat quality parameters measured during storage.
Toxicity of silver nanoparticles on endometrial receptivity in female mice
Authors: Ajdary Marziyeh , Eghbali Sahar , Mahabadi Vahid Pirhajati , Keyhanfar Fariborz , Varma Rajender S.
Published: July 2021

Nanoparticles (NPs) have many toxic effects on fertility and can prevent successful implantation by affecting the maternal uterine tissue. Herein, by deploying 30 female NMRI mice, the effect of silver NPs on the endometrium and implantation has been investigated. Using spherical silver NPs of a diameter of 18–30 nm at doses of 2 and 4 mg/kg, mice in two groups were treated. Then, female mice mated with male mice. Endometrial tissue was extracted 4.5 days later. On the fourth day of pregnancy, the mice were anesthetized and blood samples were taken from the heart; furthermore, endometrial tissue was isolated and used for molecular tests, inductively coupled plasma, and examination of pinopods. The results revealed that the levels of interleukin 6 (IL-6) and IL-1β and the accumulation of NPs in endometrial tissue in the group receiving NPs at a dose of 4 mg/kg had a major increase relative to the other two groups (p < 0.05); the group receiving a dose of 4 mg/kg exhibited a decrease in pinopods and microvillus compared with the other two groups. According to the results, NPs can reach the endometrium, suggesting that caution should be exercised due to serious exposure to NPs throughout pregnancy.
Fluctuations and phases in baryonic matter
Authors: Brandes Len , Kaiser Norbert , Weise Wolfram
Published: July 2021

The phase structure of baryonic matter is investigated with focus on the role of fluctuations beyond the mean-field approximation. The prototype test case studied is the chiral nucleon-meson model, with added comments on the chiral quark-meson model. Applications to nuclear matter include the liquid-gas phase transition. Extensions to high baryon densities are performed for both nuclear and neutron matter. The role of vacuum fluctuations is systematically explored. It is pointed out that such fluctuations tend to stabilize the hadronic phase characterized by spontaneously broken chiral symmetry, shifting the chiral restoration transition to very high densities. This stabilization effect is shown to be further enhanced by additional dynamical fluctuations treated with functional renormalisation group methods.
Test of gravitational red-shift based on tri-frequency combination of microwave frequency links
Authors: Sun Xiao , Shen Wen-Bin , Shen Ziyu , Cai Chenghui , Xu Wei , Zhang Pengfei
Published: July 2021

Over the decades, testing gravitational red-shift (GRS) based on microwave links has made great process, including the GPA experiment, the planned Atomic Clock Ensemble in Space mission, and the China Space Station (CSS). Until now, the formulations of microwave links are almost all based on the time comparison. However, there are advantages of using frequency comparison instead of time comparison to test GRS. Here we develop a tri-frequency combination method based on the measurements of the frequency shifts of three independent microwave links between a space station and a ground station. Aiming at the frequency links’ accuracy of $$3\times 10^{-16}$$

3
×

10

-
16

, we should consider various effects, including the Doppler effect, second-order Doppler effect, atmospheric frequency shift, tidal effects, refraction caused by the atmosphere, and Shapiro effect, with accuracy levels of tens of centimeters. The CSS will complete construction in 2022, and the formulation proposed in this study will enable us to test GRS at an accuracy level of at least $$2\times 10^{-6}$$

2
×

10

-
6

, which is one order higher than the present accuracy level of $$7\times 10^{-5}$$

7
×

10

-
5

.
Prospecting black hole thermodynamics with fractional quantum mechanics
Authors: Jalalzadeh S. , da Silva F. Rodrigues , Moniz P. V.
Published: July 2021

This paper investigates whether the framework of fractional quantum mechanics can broaden our perspective of black hole thermodynamics. Concretely, we employ a space-fractional derivative (Riesz in Acta Math 81:1, 1949) as our main tool. Moreover, we restrict our analysis to the case of a Schwarzschild configuration. From a subsequently modified Wheeler–DeWitt equation, we retrieve the corresponding expressions for specific observables. Namely, the black hole mass spectrum, M, its temperature T, and entropy, S. We find that these bear consequential alterations conveyed through a fractional parameter, $$\alpha $$
α
. In particular, the standard results are recovered in the specific limit $$\alpha =2$$

α
=
2

. Furthermore, we elaborate how generalizations of the entropy-area relation suggested by Tsallis and Cirto (Eur Phys J C 73:2487, 2013) and Barrow (Phys Lett B 808:135643, 2020) acquire a complementary interpretation in terms of a fractional point of view. A thorough discussion of our results is presented.
Sasakians and the geometry of a mass term
Authors: Nair V. P.
Published: July 2021

A gauge-invariant mass term for nonabelian gauge fields in two dimensions can be expressed as the Wess–Zumino–Witten (WZW) action. Hard thermal loops in the gauge theory in four dimensions at finite temperatures generate a screening mass for some components of the gauge field. This can be expressed in terms of the WZW action using the bundle of complex structures (for Euclidean signature) or the bundle of lightcones over Minkowski space. We show that a dynamically generated mass term in three dimensions can be put within the same general framework using the bundle of Sasakian structures.
Low-scale minimal linear seesaw model for neutrino mass and flavor mixing
Authors: Matute Ernesto A.
Published: July 2021

We consider an extension of the Standard Model with three right-handed (RH) neutrinos and a Dirac pair of extra sterile neutrinos, odd under a discrete [Formula: see text] symmetry, in order to have left–right symmetry in the neutrino content and obtain tiny neutrino masses from the latter ones only. Our working hypothesis is that the heavy RH neutrinos do not influence phenomenology at low energies. We use the usual high-scale seesaw to suppress all of the mass terms involving RH neutrinos and a low-scale minimal variant of the linear seesaw led by the Dirac mass of the extra sterile neutrinos to provide the small mass of active neutrinos. One of the active neutrinos is massless, which fixes the mass of the other two on the basis of a soft breaking of the [Formula: see text] symmetry. The mixing between the extra neutrinos makes for a particle that effectively behaves like a Dirac sterile neutrino with mass around the GeV level.
SBFE Virtual Particle Boundary: A New Non-Reflecting Boundary in SPH
Authors: Zhao Zibin , Li S. M. , Zhang Hao , Yin Yihui
Published: July 2021

Smoothed Particle Hydrodynamics (SPH) has outstanding advantages in dealing with nonlinear problems. However, it is difficult to find an efficient and accurate non-reflecting boundary for SPH. In this paper, the scaled boundary finite element (SBFE) virtual particle boundary is proposed to model the non-reflecting characteristics of the boundary in SPH. It is implemented by 2–4 layers of SBFE virtual particles whose pressure and velocity are calculated by the Lagrange interpolation from the nearby SBFE nodes. The SBFE virtual particle boundary can effectively and accurately simulate the transmission process of pressure waves on the boundary, and eliminate the influence of the reflecting waves on pressure and velocity fields.
Euploid Day-5 Blastocysts Versus Euploid Day-6 Blastocysts — Will the Reproductive Outcomes Differ? An Observational Study
Authors: Rao Durga Gedela , Mantravadi Krishna Chaitanya , Sharanappa Vijay Kumar
Published: July 2021

Background and objective: Day-5 blastocyst embryos are usually chosen for assisted reproductive therapy. We compared the reproductive outcomes of the euploid blastocysts developed on Day 5 versus Day 6.

Methods: This single-center, retrospective observational study analyzed patients aged 25–45 years, who underwent intracytoplasmic sperm injection from December 2014 to November 2018. Depending on the day of trophectoderm biopsy, patients were categorized into Day-5 and Day-6 groups. Percentages of euploid embryos were calculated for both groups, and elective single euploid blastocysts were transferred in a frozen embryo transfer (FET) cycles. The study endpoints were the comparisons of the reproductive outcomes including clinical pregnancy rate (CPR), implantation rate (IR), miscarriage rate (MR), and live birth rate (LBR) between Day-5 and Day-6 euploid FET groups.

Results: A total of 801 embryos from 184 patients were evaluated [Day 5 ([Formula: see text]); Day 6 ([Formula: see text]); 42.45% were euploid] with the rate of euploidy in Day-5 and Day-6 groups at 42.52% and 40.62%, respectively. A total of 126 patients underwent FET with 126 elective single euploid embryos (Day 5: 117; Day 6: 9). For Day-5 versus Day-6 groups, a significantly higher IR (61.54% vs. 44.44%; [Formula: see text]), CPR (61.54% vs. 44.44%; [Formula: see text]), and LBR (61.54% vs. 33.33%; [Formula: see text]) were reported. Multivariate analysis on ANOVA suggested, comparable pregnancy rates at Day 5 and Day 6 ([Formula: see text]).

Conclusions: Day-5 euploid blastocysts seem to offer better reproductive outcomes than Day-6 euploid blastocysts. Further research is recommended to evaluate the reproductive outcomes of Day-6 blastocysts.
System Characterization and Adaptive Tracking Control of Quadrotors under Multiple Operating Conditions
Authors: Sheng Yu , Tao Gang
Published: July 2021

This paper presents an adaptive controller design framework with input compensation for quadrotor systems, which deals with different system operating conditions with a uniform update law for the controller parameters. The motivation of the work is to handle the situation that existing adaptive control schemes are either restricted to the system equilibrium as the hover condition or unable to deal with the diverse system uncertainties which cause system interactor matrix and high-frequency gain matrix to change. An adaptive control scheme equipped with an input compensator is constructed to make the system to have a uniform interactor matrix and a consistent pattern of the gain matrix signs over different operating conditions, which are key prior design conditions for model reference adaptive control applied to quadrotor systems. To deal with the uncertain system high-frequency gain matrix, a gain matrix decomposition technique is employed to parametrize an error system model in terms of the gain parameters and tracking errors, for the design of an adaptive parameter update law with reduced system knowledge. It is ensured that all closed-loop system signals are bounded, and the system output tracks a reference output asymptotically despite the system parameter uncertainties and the uncertain offsets at non-equilibrium operating conditions. The proposed scheme expands the capacity of adaptive control for quadrotors to operate at multiple operating conditions in the presence of system uncertainties. Simulation results of a quadrotor with the proposed adaptive control scheme are presented to show the desired system performance.
Decentralized MPC-Based Trajectory Generation for Multiple Quadrotors in Cluttered Environments
Authors: Wang Xinyi , Xi Lele , Chen Yizhou , Lai Shupeng , Lin Feng , Chen Ben M.
Published: July 2021

Challenges in motion planning for multiple quadrotors in complex environments lie in overall flight efficiency and the avoidance of obstacles, deadlock, and collisions among themselves. In this paper, we present a gradient-free trajectory generation method for multiple quadrotors in dynamic obstacle-dense environments with the consideration of time consumption. A model predictive control (MPC)-based approach for each quadrotor is proposed to achieve distributed and asynchronous cooperative motion planning. First, the motion primitives of each quadrotor are formulated as the boundary state constrained primitives (BSCPs) which are constructed with jerk limited trajectory (JLT) generation method, a boundary value problem (BVP) solver, to obtain time-optimal trajectories. They are then approximated with a neural network (NN), pre-trained using this solver to reduce the computational burden. The NN is used for fast evaluation with the guidance of a navigation function during optimization to guarantee flight safety without deadlock. Finally, the reference trajectories are generated using the same BVP solver. Our simulation and experimental results demonstrate the superior performance of the proposed method.
Approaches for Multilingual Phone Recognition in Code-switched and Non-code-switched Scenarios Using Indian Languages
Authors: E. Manjunath K. , M. Srinivasa Raghavan K. , Rao K. Sreenivasa , Jayagopi Dinesh Babu , Ramasubramanian V.
Published: July 2021

In this study, we evaluate and compare two different approaches for multilingual phone recognition in code-switched and non-code-switched scenarios. First approach is a front-end Language Identification (LID)-switched to a monolingual phone recognizer (LID-Mono), trained individually on each of the languages present in multilingual dataset. In the second approach, a
common multilingual phone-set
derived from the International Phonetic Alphabet (IPA) transcription of the multilingual dataset is used to develop a Multilingual Phone Recognition System (Multi-PRS). The bilingual code-switching experiments are conducted using Kannada and Urdu languages. In the first approach, LID is performed using the state-of-the-art i-vectors. Both monolingual and multilingual phone recognition systems are trained using Deep Neural Networks. The performance of LID-Mono and Multi-PRS approaches are compared and analysed in detail. It is found that the performance of Multi-PRS approach is superior compared to more conventional LID-Mono approach in both code-switched and non-code-switched scenarios. For code-switched speech, the effect of length of segments (that are used to perform LID) on the performance of LID-Mono system is studied by varying the window size from 500 ms to 5.0 s, and full utterance. The LID-Mono approach heavily depends on the accuracy of the LID system and the LID errors cannot be recovered. But, the Multi-PRS system by virtue of not having to do a front-end LID switching and designed based on the
common multilingual phone-set
derived from several languages, is not constrained by the accuracy of the LID system, and hence performs effectively on code-switched and non-code-switched speech, offering low Phone Error Rates than the LID-Mono system.
AMP
Authors: Peng Xue Bin , Ma Ze , Abbeel Pieter , Levine Sergey , Kanazawa Angjoo
Published: July 2021

Synthesizing graceful and life-like behaviors for physically simulated characters has been a fundamental challenge in computer animation. Data-driven methods that leverage motion tracking are a prominent class of techniques for producing high fidelity motions for a wide range of behaviors. However, the effectiveness of these tracking-based methods often hinges on carefully designed objective functions, and when applied to large and diverse motion datasets, these methods require significant additional machinery to select the appropriate motion for the character to track in a given scenario. In this work, we propose to obviate the need to manually design imitation objectives and mechanisms for motion selection by utilizing a fully automated approach based on adversarial imitation learning. High-level task objectives that the character should perform can be specified by relatively simple reward functions, while the low-level style of the character's behaviors can be specified by a dataset of unstructured motion clips, without any explicit clip selection or sequencing. For example, a character traversing an obstacle course might utilize a task-reward that only considers forward progress, while the dataset contains clips of relevant behaviors such as running, jumping, and rolling. These motion clips are used to train an adversarial motion prior, which specifies style-rewards for training the character through reinforcement learning (RL). The adversarial RL procedure automatically selects which motion to perform, dynamically interpolating and generalizing from the dataset. Our system produces high-quality motions that are comparable to those achieved by state-of-the-art tracking-based techniques, while also being able to easily accommodate large datasets of unstructured motion clips. Composition of disparate skills emerges automatically from the motion prior, without requiring a high-level motion planner or other task-specific annotations of the motion clips. We demonstrate the effectiveness of our framework on a diverse cast of complex simulated characters and a challenging suite of motor control tasks.
Revisiting integration in the material point method
Authors: Fei Yun (Raymond) , Guo Qi , Wu Rundong , Huang Li , Gao Ming
Published: July 2021

The material point method (MPM) recently demonstrated its efficacy at simulating many materials and the coupling between them on a massive scale. However, in scenarios containing debris, MPM manifests more dissipation and numerical viscosity than traditional Lagrangian methods. We have two observations from carefully revisiting existing integration methods used in MPM. First, nearby particles would end up with smoothed velocities without recovering momentum for each particle during the particle-grid-particle transfers. Second, most existing integrators assume continuity in the entire domain and advect particles by directly interpolating the positions from deformed nodal positions, which would trap the particles and make them harder to separate. We propose an integration scheme that corrects particle positions at each time step. We demonstrate our method's effectiveness with several large-scale simulations involving brittle materials. Our approach effectively reduces diffusion and unphysical viscosity compared to traditional integrators.
MOCCA
Authors: Wang Ziqi , Song Peng , Pauly Mark
Published: July 2021

We present a computational framework for modeling and optimizing complex assemblies using cone joints. Cone joints are integral joints that generalize traditional single-direction joints such as mortise and tenon joints to support a general cone of directions for assembly. This additional motion flexibility not just reduces the risk of deadlocking for complex joint arrangements, but also simplifies the assembly process, in particular for automatic assembly by robots. On the other hand, compared to planar contacts, cone joints restrict relative part movement for improved structural stability. Cone joints can be realized in the form of curved contacts between associated parts, which have demonstrated good mechanical properties such as reduced stress concentration. To find the best trade-off between assemblability and stability, we propose an optimization approach that first determines the optimal motion cone for each part contact and subsequently derives a geometric realization of each joint to match this motion cone. We demonstrate that our approach can optimize cone joints for assemblies with a variety of geometric forms, and highlight several application examples.
Pareto gamuts
Authors: Makatura Liane , Guo Minghao , Schulz Adriana , Solomon Justin , Matusik Wojciech
Published: July 2021

Manufactured parts are meticulously engineered to perform well with respect to several conflicting metrics, like weight, stress, and cost. The best achievable trade-offs reside on the
Pareto front
, which can be discovered via performance-driven optimization. The objectives that define this Pareto front often incorporate assumptions about the
context
in which a part will be used, including loading conditions, environmental influences, material properties, or regions that must be preserved to interface with a surrounding assembly. Existing multi-objective optimization tools are only equipped to study one context at a time, so engineers must run independent optimizations for each context of interest. However, engineered parts frequently appear in many contexts: wind turbines must perform well in many wind speeds, and a bracket might be optimized several times with its bolt-holes fixed in different locations on each run. In this paper, we formulate a framework for variable-context multi-objective optimization. We introduce the
Pareto gamut
, which captures Pareto fronts over a range of contexts. We develop a global/local optimization algorithm to discover the Pareto gamut directly, rather than discovering a single fixed-context "slice" at a time. To validate our method, we adapt existing multi-objective optimization benchmarks to contextual scenarios. We also demonstrate the practical utility of Pareto gamut exploration for several engineering design problems.
A fitted radiance and attenuation model for realistic atmospheres
Authors: Wilkie Alexander , Vevoda Petr , Bashford-Rogers Thomas , Hošek Lukáš , Iser Tomáš , Kolářová Monika , Rittig Tobias , Křivánek Jaroslav
Published: July 2021

We present a fitted model of sky dome radiance and attenuation for realistic terrestrial atmospheres. Using scatterer distribution data from atmospheric measurement data, our model considerably improves on the visual realism of existing analytical clear sky models, as well as of interactive methods that are based on approximating atmospheric light transport. We also provide features not found in fitted models so far: radiance patterns for post-sunset conditions, in-scattered radiance and attenuation values for finite viewing distances, an observer altitude resolved model that includes downward-looking viewing directions, as well as polarisation information. We introduce a fully spherical model for in-scattered radiance that replaces the family of hemispherical functions originally introduced by Perez et al., and which was extended for several subsequent analytical models: our model relies on reference image compression via tensor decomposition instead.
Codimensional incremental potential contact
Authors: Li Minchen , Kaufman Danny M. , Jiang Chenfanfu
Published: July 2021

We extend the incremental potential contact (IPC) model [Li et al. 2020a] for contacting elastodynamics to resolve systems composed of codimensional degrees-of-freedoms in arbitrary combination. This enables a unified, interpenetration-free, robust, and stable simulation framework that couples codimension-0,1,2, and 3 geometries seamlessly with frictional contact. Extending the IPC model to thin structures poses new challenges in computing strain, modeling thickness and determining collisions. To address these challenges we propose three corresponding contributions. First, we introduce a
C
2
constitutive barrier model that directly enforces strain limiting as an energy potential while preserving rest state. This provides energetically-consistent strain limiting models (both isotropic and anisotropic) for cloth that enable strict satisfaction of strain-limit inequalities with direct coupling to both elastodynamics and contact via minimization of the incremental potential. Second, to capture the geometric thickness of codimensional domains we extend the IPC model to directly enforce distance offsets. Our treatment imposes a strict guarantee that mid-surfaces (respectively mid-lines) of shells (respectively rods) will not move closer than applied thickness values, even as these thicknesses become characteristically small. This enables us to account for thickness in the contact behavior of codimensional structures and so robustly capture challenging contacting geometries; a number of which, to our knowledge, have not been simulated before. Third, codimensional models, especially with modeled thickness, mandate strict accuracy requirements that pose a severe challenge to all existing continuous collision detection (CCD) methods. To address these limitations we develop a new, efficient, simple-to-implement
additive CCD
(ACCD) method that applies conservative advancement [Mirtich 1996; Zhang et al. 2006] to iteratively refine a lower bound for deforming primitives, converging to time of impact. In combination these contributions enable
codimensional
IPC (C-IPC). We perform extensive benchmark experiments to validate the efficacy of our method in capturing intricate behaviors of thin-structure contact and resulting bulk effects. In our experiments C-IPC obtains feasible, convergent, and so artifact-free solutions for all time steps, across all tested examples - producing robust simulations. We test C-IPC across extreme deformations, large time steps, and exceedingly close contact over all possible pairings of codimensional domains. Finally, with our strain-limit model, we confirm C-IPC guarantees non-intersection and strain-limit satisfaction for all reasonable (and well below - verified down to 0.1%) strain limits throughout all time steps.
Interactive modelling of volumetric musculoskeletal anatomy
Authors: Abdrashitov Rinat , Bang Seungbae , Levin David , Singh Karan , Jacobson Alec
Published: July 2021

We present a new approach for modelling musculoskeletal anatomy. Unlike previous methods, we do not model individual muscle shapes as geometric primitives (polygonal meshes, NURBS etc.). Instead, we adopt a volumetric segmentation approach where every point in our volume is assigned to a muscle, fat, or bone tissue. We provide an interactive modelling tool where the user controls the segmentation via muscle curves and we visualize the muscle shapes using volumetric rendering. Muscle curves enable intuitive yet powerful control over the muscle shapes. This representation allows us to automatically handle intersections between different tissues (muscle-muscle, muscle-bone, and muscle-skin) during the modelling and automates computation of muscle fiber fields. We further introduce a novel algorithm for converting the volumetric muscle representation into tetrahedral or surface geometry for use in downstream tasks. Additionally, we introduce an interactive skeleton authoring tool that allows the users to create skeletal anatomy starting from only a skin mesh using a library of bone parts.
The shape matching element method
Authors: Trusty Ty , Chen Honglin , Levin David I. W.
Published: July 2021

We introduce a new method for direct physics-based animation of volumetric curved models, represented using NURBS surfaces. Our technical contribution is the Shape Matching Element Method (SEM). SEM is a completely meshless algorithm, the first to simultaneously be robust to gaps and overlaps in geometry, be compatible with standard constitutive models and time integration schemes, support contact and frictional interactions and to preserve feature correspondence during simulation which enables editable simulated output. We demonstrate the efficacy of our algorithm by producing compelling physics-based animations from a variety of curved input models.
Dynamic closest color warping to sort and compare palettes
Authors: kim Suzi , Choi Sunghee
Published: July 2021

A color palette is one of the simplest and most intuitive descriptors that can be extracted from images or videos. This paper proposes a method to assess the similarity between color palettes by sorting colors. While previous palette similarity measures compare only colors without considering the overall palette combination, we sort palettes to minimize the geometric distance between colors and align them to share a common color tendency. We propose dynamic closest color warping (DCCW) to calculate the minimum distance sum between colors and the graph connecting the colors in the other palette. We evaluate the proposed palette sorting and DCCW with several datasets and demonstrate that DCCW outperforms previous methods in terms of accuracy and computing time. We validate the effectiveness of the proposed sorting technique by conducting a perceptual study, which indicates a clear preference for the results of our approach. We also demonstrate useful applications enabled by DCCW, including palette interpolation, palette navigation, and image recoloring.
Fast linking numbers for topology verification of loopy structures
Authors: Qu Ante , James Doug L.
Published: July 2021

It is increasingly common to model, simulate, and process complex materials based on loopy structures, such as in yarn-level cloth garments, which possess topological constraints between inter-looping curves. While the input model may satisfy specific topological linkages between pairs of closed loops, subsequent processing may violate those topological conditions. In this paper, we explore a family of methods for efficiently computing and verifying linking numbers between closed curves, and apply these to applications in geometry processing, animation, and simulation, so as to verify that topological invariants are preserved during and after processing of the input models. Our method has three stages: (1) we identify potentially interacting loop-loop pairs, then (2) carefully discretize each loop's spline curves into line segments so as to enable (3) efficient linking number evaluation using accelerated kernels based on either counting projected segment-segment crossings, or by evaluating the Gauss linking integral using direct or fast summation methods (Barnes-Hut or fast multipole methods). We evaluate CPU and GPU implementations of these methods on a suite of test problems, including yarn-level cloth and chainmail, that involve significant processing: physics-based relaxation and animation, user-modeled deformations, curve compression and reparameterization. We show that topology errors can be efficiently identified to enable more robust processing of loopy structures.
Only a matter of style
Authors: Alaluf Yuval , Patashnik Or , Cohen-Or Daniel
Published: July 2021

The task of age transformation illustrates the change of an individual's appearance over time. Accurately modeling this complex transformation over an input facial image is extremely challenging as it requires making convincing, possibly large changes to facial features and head shape, while still preserving the input identity. In this work, we present an image-to-image translation method that learns to directly encode real facial images into the latent space of a pre-trained unconditional GAN (e.g., StyleGAN) subject to a given aging shift. We employ a pre-trained age regression network to explicitly guide the encoder in generating the latent codes corresponding to the desired age. In this formulation, our method approaches the continuous aging process as a regression task between the input age and desired target age, providing fine-grained control over the generated image. Moreover, unlike approaches that operate solely in the latent space using a prior on the path controlling age, our method learns a more disentangled, non-linear path. Finally, we demonstrate that the end-to-end nature of our approach, coupled with the rich semantic latent space of StyleGAN, allows for further editing of the generated images. Qualitative and quantitative evaluations show the advantages of our method compared to state-of-the-art approaches. Code is available at our project page: https://yuval-alaluf.github.io/SAM.
Deep relightable appearance models for animatable faces
Authors: Bi Sai , Lombardi Stephen , Saito Shunsuke , Simon Tomas , Wei Shih-En , Mcphail Kevyn , Ramamoorthi Ravi , Sheikh Yaser , Saragih Jason
Published: July 2021

We present a method for building high-fidelity animatable 3D face models that can be posed and rendered with novel lighting environments in real-time. Our main insight is that relightable models trained to produce an image lit from a single light direction can generalize to natural illumination conditions but are computationally expensive to render. On the other hand, efficient, high-fidelity face models trained with point-light data do not generalize to novel lighting conditions. We leverage the strengths of each of these two approaches. We first train an expensive but
generalizable model
on point-light illuminations, and use it to generate a training set of high-quality synthetic face images under natural illumination conditions. We then train an
efficient model
on this augmented dataset, reducing the generalization ability requirements. As the efficacy of this approach hinges on the quality of the synthetic data we can generate, we present a study of lighting pattern combinations for dynamic captures and evaluate their suitability for learning generalizable relightable models. Towards achieving the best possible quality, we present a novel approach for generating dynamic relightable faces that exceeds state-of-the-art performance. Our method is capable of capturing subtle lighting effects and can even generate compelling near-field relighting despite being trained exclusively with far-field lighting data. Finally, we motivate the utility of our model by animating it with images captured from VR-headset mounted cameras, demonstrating the first system for face-driven interactions in VR that uses a photorealistic relightable face model.
ManipNet
Authors: Zhang He , Ye Yuting , Shiratori Takaaki , Komura Taku
Published: July 2021

Natural hand manipulations exhibit complex finger maneuvers adaptive to object shapes and the tasks at hand. Learning dexterous manipulation from data in a brute force way would require a prohibitive amount of examples to effectively cover the combinatorial space of 3D shapes and activities. In this paper, we propose a hand-object spatial representation that can achieve generalization from limited data. Our representation combines the global object shape as voxel occupancies with local geometric details as samples of closest distances. This representation is used by a neural network to regress finger motions from input trajectories of wrists and objects. Specifically, we provide the network with the current finger pose, past and future trajectories, and the spatial representations extracted from these trajectories. The network then predicts a new finger pose for the next frame as an autoregressive model. With a carefully chosen hand-centric coordinate system, we can handle single-handed and two-handed motions in a unified framework. Learning from a small number of primitive shapes and kitchenware objects, the network is able to synthesize a variety of finger gaits for grasping, in-hand manipulation, and bimanual object handling on a rich set of novel shapes and functional tasks. We also demonstrate a live demo of manipulating virtual objects in real-time using a simple physical prop. Our system is useful for offline animation or real-time applications forgiving to a small delay.
Designing an encoder for StyleGAN image manipulation
Authors: Tov Omer , Alaluf Yuval , Nitzan Yotam , Patashnik Or , Cohen-Or Daniel
Published: July 2021

Recently, there has been a surge of diverse methods for performing image editing by employing pre-trained unconditional generators. Applying these methods on real images, however, remains a challenge, as it necessarily requires the inversion of the images into their latent space. To successfully invert a real image, one needs to find a latent code that reconstructs the input image accurately, and more importantly, allows for its meaningful manipulation. In this paper, we carefully study the latent space of StyleGAN, the state-of-the-art unconditional generator. We identify and analyze the existence of a distortion-editability tradeoff and a distortion-perception tradeoff within the StyleGAN latent space. We then suggest two principles for designing encoders in a manner that allows one to control the proximity of the inversions to regions that StyleGAN was originally trained on. We present an encoder based on our two principles that is specifically designed for facilitating editing on real images by balancing these tradeoffs. By evaluating its performance qualitatively and quantitatively on numerous challenging domains, including cars and horses, we show that our inversion method, followed by common editing techniques, achieves superior real-image editing quality, with only a small reconstruction accuracy drop.