HASTY, the Arabidopsis EXPORTIN5 ortholog, regulates cell-to-cell and vascular microRNA movement.

Plant microRNAs (miRNAs) guide cytosolic post-transcriptional gene silencing of sequence-complementary transcripts within the producing cells, as well as in distant cells and tissues. Here, we used an artificial miRNA-based system (amiRSUL) in Arabidopsis thaliana to explore the still elusive mechanisms of inter-cellular miRNA movement via forward genetics. This screen identified many mutant alleles of HASTY (HST), the ortholog of mammalian EXPORTIN5 (XPO5) with a recently reported role in miRNA biogenesis in Arabidopsis. In both epidermis-peeling and grafting assays, amiRSUL levels were reduced much more substantially in miRNA-recipient tissues than in silencing-emitting tissues. We ascribe this effect to HST controlling cell-to-cell and phloem-mediated movement of the processed amiRSUL, in addition to regulating its biogenesis. While HST is not required for the movement of free GFP or siRNAs, its cell-autonomous expression in amiRSUL-emitting tissues suffices to restore amiRSUL movement independently of its nucleo-cytosolic shuttling activity. By contrast, HST is dispensable for the movement and activity of amiRSUL within recipient tissues. Finally, HST enables movement of endogenous miRNAs that display mostly unaltered steady-state levels in hst mutant tissues. We discuss a role for HST as a hitherto unrecognized regulator of miRNA movement in relation to its recently assigned nuclear function at the nexus of MIRNA transcription and miRNA processing.

Genetic architecture of dispersal and local adaptation drives accelerating range expansions.

Contemporary evolution has the potential to significantly alter biotic responses to global change, including range expansion dynamics and biological invasions. Models predicting range dynamics often make highly simplifying assumptions about the genetic architecture underlying relevant traits. However, genetic architecture defines evolvability and higher-order evolutionary processes, which determine whether evolution will be able to keep up with environmental change or not. Therefore, we here study the impact of the genetic architecture of dispersal and local adaptation, two central traits of high relevance for range expansions, on the dynamics and predictability of invasion into an environmental gradient, such as temperature. In our theoretical model we assume that dispersal and local adaptation traits result from the products of two noninteracting gene-regulatory networks (GRNs). We compare our model to simpler quantitative genetics models and show that in the GRN model, range expansions are accelerating and less predictable. We further find that accelerating dynamics in the GRN model are primarily driven by an increase in the rate of local adaptation to novel habitats which results from greater sensitivity to mutation (decreased robustness) and increased gene expression. Our results highlight how processes at microscopic scales, here within genomes, can impact the predictions of large-scale, macroscopic phenomena, such as range expansions, by modulating the rate of evolution.

In planta dynamics, transport biases, and endogenous functions of mobile siRNAs in Arabidopsis.

In RNA interference (RNAi), small interfering RNAs (siRNAs) produced from double-stranded RNA guide ARGONAUTE (AGO) proteins to silence sequence-complementary RNA/DNA. RNAi can propagate locally and systemically in plants, but despite recent advances in our understanding of the underlying mechanisms, basic questions remain unaddressed. For instance, RNAi is inferred to diffuse through plasmodesmata (PDs), yet how its dynamics in planta compares with that of established symplastic diffusion markers remains unknown. Also is why select siRNA species, or size classes thereof, are apparently recovered in RNAi recipient tissues, yet only under some experimental settings. Shootward movement of endogenous RNAi in micro-grafted Arabidopsis is also yet to be achieved, while potential endogenous functions of mobile RNAi remain scarcely documented. Here, we show (i) that temporal, localized PD occlusion in source leaves' companion cells (CCs) suffices to abrogate all systemic manifestations of CC-activated mobile transgene silencing, including in sink leaves; (ii) that the presence or absence of specific AGOs in incipient/traversed/recipient tissues likely explains the apparent siRNA length selectivity observed upon vascular movement; (iii) that stress enhancement allows endo-siRNAs of a single inverted repeat (IR) locus to translocate against the shoot-to-root phloem flow; and (iv) that mobile endo-siRNAs generated from this locus have the potential to regulate hundreds of transcripts. Our results close important knowledge gaps, rationalize previously noted inconsistencies between mobile RNAi settings, and provide a framework for mobile endo-siRNA research.

The second stage of labor.

The second stage of labor extends from complete cervical dilatation to delivery. During this stage, descent and rotation of the presenting part occur as the fetus passively negotiates its passage through the birth canal. Generally, descent begins during the deceleration phase of dilatation as the cervix is drawn upward around the fetal presenting part. The most common means of assessing the normality of the second stage of labor is to measure its duration, but progress can be more meaningfully gauged by measuring the change in fetal station as a function of time. Accurate clinical identification and evaluation of differences in patterns of fetal descent are necessary to assess second stage of labor progress and to make reasoned judgments about the need for intervention. Three distinct graphic abnormalities of the second stage of labor can be identified: protracted descent, arrest of descent, and failure of descent. All abnormalities have a strong association with cephalopelvic disproportion but may also occur in the presence of maternal obesity, uterine infection, excessive sedation, and fetal malpositions. Interpretation of the progress of fetal descent must be made in the context of other clinically discernable events and observations. These include fetal size, position, attitude, and degree of cranial molding and related evaluations of pelvic architecture and capacity to accommodate the fetus, uterine contractility, and fetal well-being. Oxytocin infusion can often resolve an arrest or failure of descent or a protracted descent caused by an inhibitory factor, such as a dense neuraxial block. It should be used only if thorough assessment of fetopelvic relationships reveals a low probability of cephalopelvic disproportion. The value of forced Valsalva pushing, fundal pressure, and routine episiotomy has been questioned. They should be used selectively and where indicated.

Biodiversity increases and decreases ecosystem stability.

Losses and gains in species diversity affect ecological stability1-7 and the sustainability of ecosystem functions and services8-13. Experiments and models have revealed positive, negative and no effects of diversity on individual components of stability, such as temporal variability, resistance and resilience2,3,6,11,12,14. How these stability components covary remains poorly understood15. Similarly, the effects of diversity on overall ecosystem stability16, which is conceptually akin to ecosystem multifunctionality17,18, remain unknown. Here we studied communities of aquatic ciliates to understand how temporal variability, resistance and overall ecosystem stability responded to diversity (that is, species richness) in a large experiment involving 690 micro-ecosystems sampled 19 times over 40 days, resulting in 12,939 samplings. Species richness increased temporal stability but decreased resistance to warming. Thus, two stability components covaried negatively along the diversity gradient. Previous biodiversity manipulation studies rarely reported such negative covariation despite general predictions of the negative effects of diversity on individual stability components3. Integrating our findings with the ecosystem multifunctionality concept revealed hump- and U-shaped effects of diversity on overall ecosystem stability. That is, biodiversity can increase overall ecosystem stability when biodiversity is low, and decrease it when biodiversity is high, or the opposite with a U-shaped relationship. The effects of diversity on ecosystem multifunctionality would also be hump- or U-shaped if diversity had positive effects on some functions and negative effects on others. Linking the ecosystem multifunctionality concept and ecosystem stability can transform the perceived effects of diversity on ecological stability and may help to translate this science into policy-relevant information.

A review of combined functional neuroimaging and motion capture for motor rehabilitation.

BACKGROUND: Technological advancements in functional neuroimaging and motion capture have led to the development of novel methods that facilitate the diagnosis and rehabilitation of motor deficits. These advancements allow for the synchronous acquisition and analysis of complex signal streams of neurophysiological data (e.g., EEG, fNIRS) and behavioral data (e.g., motion capture). The fusion of those data streams has the potential to provide new insights into cortical mechanisms during movement, guide the development of rehabilitation practices, and become a tool for assessment and therapy in neurorehabilitation. RESEARCH OBJECTIVE: This paper aims to review the existing literature on the combined use of motion capture and functional neuroimaging in motor rehabilitation. The objective is to understand the diversity and maturity of technological solutions employed and explore the clinical advantages of this multimodal approach. METHODS: This paper reviews literature related to the combined use of functional neuroimaging and motion capture for motor rehabilitation following the PRISMA guidelines. Besides study and participant characteristics, technological aspects of the used systems, signal processing methods, and the nature of multimodal feature synchronization and fusion were extracted. RESULTS: Out of 908 publications, 19 were included in the final review. Basic or translation studies were mainly represented and based predominantly on healthy participants or stroke patients. EEG and mechanical motion capture technologies were most used for biomechanical data acquisition, and their subsequent processing is based mainly on traditional methods. The system synchronization techniques at large were underreported. The fusion of multimodal features mainly supported the identification of movement-related cortical activity, and statistical methods were occasionally employed to examine cortico-kinematic relationships. CONCLUSION: The fusion of motion capture and functional neuroimaging might offer advantages for motor rehabilitation in the future. Besides facilitating the assessment of cognitive processes in real-world settings, it could also improve rehabilitative devices' usability in clinical environments. Further, by better understanding cortico-peripheral coupling, new neuro-rehabilitation methods can be developed, such as personalized proprioceptive training. However, further research is needed to advance our knowledge of cortical-peripheral coupling, evaluate the validity and reliability of multimodal parameters, and enhance user-friendly technologies for clinical adaptation.

Simulating room transfer functions between transducers mounted on audio devices using a modified image source method.

The image source method (ISM) is often used to simulate room acoustics due to its ease of use and computational efficiency. The standard ISM is limited to simulations of room impulse responses between point sources and omnidirectional receivers. In this work, the ISM is extended using spherical harmonic directivity coefficients to include acoustic diffraction effects. These effects occur in practice when transducers are mounted on audio devices of finite spatial extent, e.g., modern smart speakers with loudspeakers and microphones. The proposed method is verified using finite element simulations of various loudspeaker and microphone configurations in a shoebox-shaped room. It is shown that the accuracy of the proposed method is related to the sizes, shapes, number, and positions of the devices inside a room. A simplified version of the proposed method, which can significantly reduce computational effort, is also presented. The proposed method and its simplified version can simulate room transfer functions more accurately than currently available image source methods and can aid the development and evaluation of speech and acoustic signal processing algorithms, including speech enhancement, acoustic scene analysis, and acoustic parameter estimation.

Eco-evolution from deep time to contemporary dynamics: The role of timescales and rate modulators.

Eco-evolutionary dynamics, or eco-evolution for short, are often thought to involve rapid demography (ecology) and equally rapid heritable phenotypic changes (evolution) leading to novel, emergent system behaviours. We argue that this focus on contemporary dynamics is too narrow: Eco-evolution should be extended, first, beyond pure demography to include all environmental dimensions and, second, to include slow eco-evolution which unfolds over thousands or millions of years. This extension allows us to conceptualise biological systems as occupying a two-dimensional time space along axes that capture the speed of ecology and evolution. Using Hutchinson's analogy: Time is the 'theatre' in which ecology and evolution are two interacting 'players'. Eco-evolutionary systems are therefore dynamic: We identify modulators of ecological and evolutionary rates, like temperature or sensitivity to mutation, which can change the speed of ecology and evolution, and hence impact eco-evolution. Environmental change may synchronise the speed of ecology and evolution via these rate modulators, increasing the occurrence of eco-evolution and emergent system behaviours. This represents substantial challenges for prediction, especially in the context of global change. Our perspective attempts to integrate ecology and evolution across disciplines, from gene-regulatory networks to geomorphology and across timescales, from today to deep time.

Landscape Structure Affects Metapopulation-Scale Tipping Points.

AbstractEven when environments deteriorate gradually, ecosystems may shift abruptly from one state to another. Such catastrophic shifts are difficult to predict and sometimes to reverse (so-called hysteresis). While well studied in simplified contexts, we lack a general understanding of how catastrophic shifts spread in realistically spatially structured landscapes. For different types of landscape structures, including typical terrestrial modular and riverine dendritic networks, we here investigate landscape-scale stability in metapopulations whose patches can locally exhibit catastrophic shifts. We find that such metapopulations usually exhibit large-scale catastrophic shifts and hysteresis and that the properties of these shifts depend strongly on the metapopulation spatial structure and on the population dispersal rate: an intermediate dispersal rate, a low average degree, or a riverine spatial structure can largely reduce hysteresis size. Our study suggests that large-scale restoration is easier with spatially clustered restoration efforts and in populations characterized by an intermediate dispersal rate.

Travelling with a parasite: the evolution of resistance and dispersal syndromes during experimental range expansion.

Rapid evolutionary change during range expansions can lead to diverging range core and front populations, with the emergence of dispersal syndromes (coupled responses in dispersal and life-history traits). Besides intraspecific effects, range expansions may be impacted by interspecific interactions such as parasitism. Yet, despite the potentially large impact of parasites imposing additional selective pressures on the host, their role on range expansions remains largely unexplored. Using microcosm populations of the ciliate Paramecium caudatum and its bacterial parasite Holospora undulata, we studied experimental range expansions under parasite presence or absence. We found that the interaction of range expansion and parasite treatments affected the evolution of host dispersal syndromes. Namely, front populations showed different associations of population growth parameters and swimming behaviours than core populations, indicating divergent evolution. Parasitism reshaped trait associations, with hosts evolved in the presence of the parasite exhibiting overall increased resistance and reduced dispersal. Nonetheless, when comparing infected range core and front populations, we found a positive association, suggesting joint evolution of resistance and dispersal at the front. We conclude that host-parasite interactions during range expansions can change evolutionary trajectories; this in turn may feedback on the ecological dynamics of the range expansion and parasite epidemics.

Racial and ethnic disparities in major adverse limb events persist for chronic limb threatening ischemia despite presenting limb threat severity after peripheral vascular intervention.

OBJECTIVE: Racial and ethnic disparities have been well-documented in the outcomes for chronic limb threatening ischemia (CLTI). One purported explanation has been the disease severity at presentation. We hypothesized that the disparities in major adverse limb events (MALE) after peripheral vascular intervention (PVI) for CLTI would persist despite controlling for disease severity at presentation using the WIfI (Wound, Ischemia, foot Infection) stage. METHODS: The Vascular Quality Initiative PVI dataset (2016-2021) was queried for CLTI. Patients were excluded if they were missing the WIfI stage. The primary end point was the incidence of 1-year MALE, defined as major amputation (through the tibia or fibula or more proximally) or reintervention (endovascular or surgical) of the initial treatment limb. A multivariate hierarchical Fine-Gray analysis was performed, controlling for hospital variation, competing risk of death, and presenting WIfI stage, to assess the independent association of Black/African American race and Latinx/Hispanic ethnicity with MALE. A Cox proportional hazard regression model was used for the 1-year survival analysis. RESULTS: Overall, 47,830 patients (60%) had had WIfI scores reported (73% White, 20% Black, and 7% Latinx). The 1-year unadjusted cumulative incidence of MALE was 13.1% (95% confidence interval [CI], 12.6%-13.5%) for White, 14.3% (95% CI, 13.5%-15.3%) for Black, and 17.0% (95% CI, 15.3%-18.9%) for Latinx patients. On bivariate analysis, the occurrence of MALE was significantly associated with younger age, Black race, Latinx ethnicity, coronary artery disease, cerebrovascular disease, congestive heart failure, hypertension, diabetes, dialysis, intervention level, any prior minor or major amputation, and WIfI stage (P < .001). The cumulative incidence of 1-year MALE increased by increasing WIfI stage: stage 1, 11.7% (95% CI, 10.9%-12.4%); stage 2, 12.4% (95% CI, 11.8%-13.0%); stage 3, 14.8% (95% CI, 13.8%-15.8%); and stage 4, 15.4% (95% CI, 14.3%-16.6%). The cumulative incidence also increased by intervention level: inflow, 10.7% (95% CI, 9.8%-11.7%), femoropopliteal, 12.3% (95% CI, 11.7%-12.9%); and infrapopliteal, 14.1% (95% CI, 13.5%-14.8%). After adjustment for WIfI stage only, Black race (subdistribution hazard ratio [SHR], 1.30; 95% CI, 1.17-1.44; P < .001) and Latinx ethnicity (SHR, 1.58; 95% CI, 1.37-1.81; P < .001) were associated with an increased 1-year hazard of MALE compared with White race. On adjusted multivariable analysis, MALE disparities persisted for Black/African American race (SHR, 1.12; 95% CI, 1.01-1.25; P = .028) and Latinx/Hispanic ethnicity (SHR, 1.34; 95% CI, 1.16-1.54; P < .001) compared with White race. CONCLUSIONS: Black/African American and Latinx/Hispanic patients had a higher associated hazard of MALE after PVI for CLTI compared with White patients despite an adjustment for WIfI stage at presentation. These results suggest that disease severity at presentation does not account for disparities in outcomes. Further work should focus on better understanding the underlying mechanisms for disparities in historically marginalized racial and ethnic groups presenting with CLTI.

Structured discharge documentation reduces sex-based disparities in statin prescription in vascular surgery patients.

OBJECTIVE: Perioperative statin use has been shown to improve survival in vascular surgery patients. In 2018, the Northern California Vascular Study Group implemented a quality initiative focused on the use of a SmartText in the discharge summary. We hypothesized that structured discharge documentation would decrease sex-based disparities in evidence-based medical therapy. METHODS: A retrospective analysis was conducted using Vascular Quality Initiative eligible cases at a single institution. Open or endovascular procedures in the abdominal aorta or lower extremity arteries from 2016 to 2021 were included. Bivariate analysis identified factors associated with statin use and sex. Multivariate logistic regression was performed with the end point of statin prescription at discharge and aspirin prescription at discharge. An interaction term assessed the differential impact of the initiative on both sexes. Analysis was then stratified by prior aspirin or statin prescription. An interrupted time series analysis was used to evaluate the trend in statin prescription over time. RESULTS: Overall, 866 patients were included, including 292 (34%) female and 574 (66%) male patients. Before implementation, statins were prescribed in 77% of male and 62% of female patients (P < .01). After implementation, there was no statistically significant difference in statin prescription (91% in male vs 92% in female patients, P = .68). Female patients saw a larger improvement in the adjusted odds of statin prescription compared with male patients (odds ratio: 3.1, 95% confidence interval: 1.1-8.6, P = .04). For patients not prescribed a statin preoperatively, female patients again saw an even larger improvement in the odds of being prescribed a statin at discharge (odds ratio: 6.4, 95% confidence interval: 1.8-22.7, P < .01). Interrupted time series analysis demonstrated a sustained improvement in the frequency of prescription for both sexes over time. The unadjusted frequency of aspirin prescription also improved by 3.5% in male patients vs 5.5% in female patients. For patients not prescribed an aspirin preoperatively, we found that the frequency of aspirin prescription significantly improved for both male (19% increase, P = .006) and female (31% increase, P = .001) patients. There was no significant difference in the perioperative outcomes between male and female patients before and after standardized discharge documentation. CONCLUSIONS: A simple, low-cost regional quality improvement initiative eliminated sex-based disparities in statin prescription at a single institution. These findings highlight the meaningful impact of regional quality improvement projects. Future studies should examine the potential for structured discharge documentation to improve patient outcomes and reduce disparities.

Evolution of thermal performance curves: A meta-analysis of selection experiments.

Temperatures are increasing due to global changes, putting biodiversity at risk. Organisms are faced with a limited set of options to cope with this situation: adapt, disperse or die. We here focus on the first possibility, more specifically, on evolutionary adaptations to temperature. Ectotherms are usually characterized by a hump-shaped relationship between fitness and temperature, a non-linear reaction norm that is referred to as thermal performance curve (TPC). To understand and predict impacts of global change, we need to know whether and how such TPCs evolve. Therefore, we performed a systematic literature search and a statistical meta-analysis focusing on experimental evolution and artificial selection studies. This focus allows us to directly quantify relative fitness responses to temperature selection by calculating fitness differences between TPCs from ancestral and derived populations after thermal selection. Out of 7561 publications screened, we found 47 studies corresponding to our search criteria representing taxa across the tree of life, from bacteria, to plants and vertebrates. We show that, independently of species identity, the studies we found report a positive response to temperature selection. Considering entire TPC shapes, adaptation to higher temperatures traded off with fitness at lower temperatures, leading to niche shifts. Effects were generally stronger in unicellular organisms. By contrast, we do not find statistical support for the often discussed "Hotter is better" hypothesis. While our meta-analysis provides evidence for adaptive potential of TPCs across organisms, it also highlights that more experimental work is needed, especially for under-represented taxa, such as plants and non-model systems.

The latent phase of labor.

The latent phase of labor extends from the initiation of labor to the onset of the active phase. Because neither margin is always precisely identifiable, the duration of the latent phase often can only be estimated. During this phase, the cervix undergoes a process of rapid remodeling, which may have begun gradually weeks before. As a consequence of extensive changes in its collagen and ground substance, the cervix softens, becomes thinner and dramatically more compliant, and may dilate modestly. All of these changes prepare the cervix for the more rapid dilatation that will occur during the active phase to follow. For the clinician, it is important to recognize that the latent phase may normally extend for many hours. The normal limit for the duration of the latent phase should be considered to be approximately 20 hours in a nullipara and 14 hours in a multipara. Factors that have been associated with a prolonged latent phase include deficient prelabor or intrapartum cervical remodeling, excessive maternal analgesia or anesthesia, maternal obesity, and chorioamnionitis. Approximately 10% of women with a prolonged latent phase are actually in false labor, and their contractions eventually abate spontaneously. The management of a prolonged latent phase involves either augmenting uterine activity with oxytocin or providing a sedative-induced period of maternal rest. Both are equally effective in advancing the labor to active phase dilatation. A very long latent phase may be a harbinger of other labor dysfunctions.

The active phase of labor.

The active phase of labor begins at various degrees of dilatation when the rate of dilatation transitions from the relatively flat slope of the latent phase to a more rapid slope. No diagnostic manifestations demarcate its onset, other than accelerating dilatation. It ends with apparent slowing of dilatation, a deceleration phase, which is usually short in duration and frequently undetected. Several aberrant labor patterns can be detected during the active phase, including protracted dilatation, arrest of dilatation, prolonged deceleration phase and failure of descent. Underlying factors may include cephalopelvic disproportion, excessive neuraxial block, poor uterine contractility, fetal malpositions, malpresentations, uterine infection, maternal obesity, advanced maternal age and previous cesarean delivery. When an active-phase disorder is identified, cesarean delivery is justifiable if there is compelling clinical evidence of disproportion. A prolonged deceleration disorder is strongly associated with disproportion and second stage abnormalities. Shoulder dystocia may occur if vaginal delivery eventuates. This review discusses several issues raised by the introduction of new clinical practice guidelines for labor management.

Dysfunctional labor and delivery: adverse effects on offspring.

There is no doubt that parturition can produce fetal and neonatal adversity, but the frequency with which this occurs is uncertain, particularly in modern healthcare settings. Moreover, there is a paucity of recent studies in this area. Substantial challenges impede epidemiologic study of the effect of parturition on offspring. Randomized trials would be ethically fraught. Therefore, large observational samples with detailed data concerning labor and delivery events are needed. Importantly, long-term follow-up of infants is necessary to reach reliable conclusions. Few such data sets exist, and it is difficult, expensive, and time-consuming to create and to study them. Reports of immediate newborn condition in relation to the antecedent labor are helpful, but this evidence is an imperfect predictor of long-term neurologic status. In this review, we endeavor to summarize existing information about the relationship between objectively defined abnormalities of labor progress and long-term disability in offspring. The only data available are from collected experiential information on outcomes stratified according to labor and delivery events. Most studies do not ensure against confounding by the many concurrent conditions that may affect outcome, or use inconsistent criteria to define abnormal labor. According to the best available evidence, dysfunctional labor patterns are potentially associated with poor outcomes for surviving infants. The question of whether these adverse effects can be mitigated by early diagnosis and expeditious management deserves to be answered, but cannot be at this time. In the absence of more conclusive results from well-designed studies, we can conclude that the best interests of offspring are served by adhering to evidence-based paradigms for the prompt identification and treatment of dysfunctional labor patterns.

Experimental evolution of dispersal: Unifying theory, experiments and natural systems.

Dispersal is a central life history trait that affects the ecological and evolutionary dynamics of populations and communities. The recent use of experimental evolution for the study of dispersal is a promising avenue for demonstrating valuable proofs of concept, bringing insight into alternative dispersal strategies and trade-offs, and testing the repeatability of evolutionary outcomes. Practical constraints restrict experimental evolution studies of dispersal to a set of typically small, short-lived organisms reared in artificial laboratory conditions. Here, we argue that despite these restrictions, inferences from these studies can reinforce links between theoretical predictions and empirical observations and advance our understanding of the eco-evolutionary consequences of dispersal. We illustrate how applying an integrative framework of theory, experimental evolution and natural systems can improve our understanding of dispersal evolution under more complex and realistic biological scenarios, such as the role of biotic interactions and complex dispersal syndromes.

Identification of High-Reliability Regions of Machine Learning Predictions Based on Materials Chemistry.

Progress in the application of machine learning (ML) methods to materials design is hindered by the lack of understanding of the reliability of ML predictions, in particular, for the application of ML to small data sets often found in materials science. Using ML prediction for transparent conductor oxide formation energy and band gap, dilute solute diffusion, and perovskite formation energy, band gap, and lattice parameter as examples, we demonstrate that (1) construction of a convex hull in feature space that encloses accurately predicted systems can be used to identify regions in feature space for which ML predictions are highly reliable; (2) analysis of the systems enclosed by the convex hull can be used to extract physical understanding; and (3) materials that satisfy all well-known chemical and physical principles that make a material physically reasonable are likely to be similar and show strong relationships between the properties of interest and the standard features used in ML. We also show that similar to the composition-structure-property relationships, inclusion in the ML training data set of materials from classes with different chemical properties will not be beneficial for the accuracy of ML prediction and that reliable results likely will be obtained by ML model for narrow classes of similar materials even in the case where the ML model will show large errors on the data set consisting of several classes of materials.

From temporal to spatial topography: hierarchy of neural dynamics in higher- and lower-order networks shapes their complexity.

The brain shows a topographical hierarchy along the lines of lower- and higher-order networks. The exact temporal dynamics characterization of this lower-higher-order topography at rest and its impact on task states remains unclear, though. Using 2 functional magnetic resonance imaging data sets, we investigate lower- and higher-order networks in terms of the signal compressibility, operationalized by Lempel-Ziv complexity (LZC). As we assume that this degree of complexity is related to the slow-fast frequency balance, we also compute the median frequency (MF), an estimation of frequency distribution. We demonstrate (i) topographical differences at rest between higher- and lower-order networks, showing lower LZC and MF in the former; (ii) task-related and task-specific changes in LZC and MF in both lower- and higher-order networks; (iii) hierarchical relationship between LZC and MF, as MF at rest correlates with LZC rest-task change along the lines of lower- and higher-order networks; and (iv) causal and nonlinear relation between LZC at rest and LZC during task, with MF at rest acting as mediator. Together, results show that the topographical hierarchy of lower- and higher-order networks converges with their temporal hierarchy, with these neural dynamics at rest shaping their range of complexity during task states in a nonlinear way.

Online reverberation time and clarity estimation in dynamic acoustic conditions.

Previously proposed methods for estimating acoustic parameters from reverberant, noisy speech signals exhibit insufficient performance under changing acoustic conditions. A data-centric approach is proposed to overcome the limiting assumption of fixed source-receiver transmission paths. The obtained solution significantly enlarges the scope of potential applications for such estimators. The joint estimation of reverberation time RT60 and clarity index C50 in multiple frequency bands is studied with a focus on dynamic acoustic environments. Three different convolutional recurrent neural network architectures are considered to solve the tasks of single-band, multi-band, and multi-task parameter estimation. A comprehensive performance evaluation is provided that highlights the benefits of the proposed approach.