Time Discrepancy Research Articles

Diatom-inferred centennial-millennial postglacial climate change in the Pacific Northwest of North America

A diatom record from Moss Lake, Washington, USA spans the last 14,500 cal year and revealed Holocene climate change in the Pacific Northwest (PNW), including evidence for periodicities related to ocean-atmosphere teleconnections and/or variations in solar output. Three main climate phases were identified: (i) Late Pleistocene to early Greenlandian (until 10,800 cal year BP, spanning GI-1, GS-1), with a cold climate and low diatom abundance; (ii) early Greenlandian to Northgrippian (10,800–7500 cal year BP), shifting to a warmer climate; and (iii) late Northgrippian and Meghalayan from 7500 cal year BP onwards, with a cooler, moist climate. These climate shifts are in good agreement with the pollen record from the same core and other regional studies. Fluctuations in Discostella pseudostelligera and Aulacoseira taxa suggest climate cycles of different frequency and amplitude throughout the record. Spectral and wavelet analyses revealed periodicities of approximately 1400 and 400–500 years. We interpret the ~ 1400-year and ~ 400–500-year cycles to reflect alternating periods of enhanced (and reduced) convective mixing in the water column, associated with increased (and decreased) storms, resulting from ocean–atmosphere teleconnections in the wider Pacific region. The ~ 1400-year periodicity is evident throughout the Late Pleistocene and late Northgrippian/Meghalayan, reflecting high-amplitude millennial shifts from periods of stable thermal stratification of the water column (weak wind intensity) to periods of convective mixing (high wind intensity). The millennial cycle diminishes during the Greenlandian, in association with the boreal summer insolation maximum, consistent with suppression of ENSO-like dynamics by enhanced trade winds. Ocean–atmosphere teleconnection suppression is recorded throughout the PNW, but there is a time discrepancy with other records, some that reveal suppression during the Greenlandian and others during the Northgrippian, suggesting endogenic processes may also modulate the Moss Lake diatom record. The large amplitude of millennial variability indicated by the lake data suggests that regional climate in the PNW was characterised over the longer term by shifting influences of ocean–atmosphere dynamics and that an improved understanding of the external forcing is necessary for understanding past and future climate conditions in western North America.

A Generalized Conditional Gradient Method for Dynamic Inverse Problems with Optimal Transport Regularization

We develop a dynamic generalized conditional gradient method (DGCG) for dynamic inverse problems with optimal transport regularization. We consider the framework introduced in Bredies and Fanzon (ESAIM: M2AN 54:2351–2382, 2020), where the objective functional is comprised of a fidelity term, penalizing the pointwise in time discrepancy between the observation and the unknown in time-varying Hilbert spaces, and a regularizer keeping track of the dynamics, given by the Benamou–Brenier energy constrained via the homogeneous continuity equation. Employing the characterization of the extremal points of the Benamou–Brenier energy (Bredies et al. in Bull Lond Math Soc 53(5):1436–1452, 2021), we define the atoms of the problem as measures concentrated on absolutely continuous curves in the domain. We propose a dynamic generalization of a conditional gradient method that consists of iteratively adding suitably chosen atoms to the current sparse iterate, and subsequently optimizing the coefficients in the resulting linear combination. We prove that the method converges with a sublinear rate to a minimizer of the objective functional. Additionally, we propose heuristic strategies and acceleration steps that allow to implement the algorithm efficiently. Finally, we provide numerical examples that demonstrate the effectiveness of our algorithm and model in reconstructing heavily undersampled dynamic data, together with the presence of noise.

Mass Transfer as an Explanation for the Lifetime Travel Time Discrepancy in IT Librae

Abstract The eclipsing binary IT Librae is an unusual system of two B-type stars that is situated about 1 kpc above the Galactic plane. The binary was probably ejected from its birthplace in the disk, but the implied time of flight to its current location exceeds the evolutionary lifetime of the primary star. Here we present a study of new high-dispersion spectroscopy and an exquisite light curve from the Kepler K2 mission in order to determine the system properties and resolve the timescale discrepancy. We derive a revised spectroscopic orbit from radial-velocity measurements and determine the component effective temperatures through comparison of reconstructed and model spectra (T 1 = 23.8 ± 1.8 kK, T 2 = 13.7 ± 2.5 kK). We use the Eclipsing Light Curve code to model the K2 light curve, and from the inclination of the fit we derive the component masses (M 1 = 9.6 ± 0.6 M ⊙, M 2 = 4.2 ± 0.2 M ⊙) and mean radii (R 1 = 6.06 ± 0.16 R ⊙, R 2 = 5.38 ± 0.14 R ⊙). The secondary star is overluminous for its mass and appears to fill its Roche lobe. This indicates that IT Librae is a post-mass-transfer system in which the current secondary was the mass donor star. The current primary star was rejuvenated by mass accretion, and its evolutionary age corresponds to the time since the mass transfer stage. Consequently, the true age of the binary is larger than the ejection time of flight, thus resolving the timescale discrepancy.

Pre-Sleep Cognitive Arousal Is Negatively Associated with Sleep Misperception in Healthy Sleepers during Habitual Environmental Noise Exposure: An Actigraphy Study.

Specific noises (e.g., traffic or wind turbines) can disrupt sleep and potentially cause a mismatch between subjective sleep and objective sleep (i.e., “sleep misperception”). Some individuals are likely to be more vulnerable than others to noise-related sleep disturbances, potentially as a result of increased pre-sleep cognitive arousal. The aim of the present study was to examine the relationships between pre-sleep cognitive arousal and sleep misperception. Sixteen healthy sleepers participated in this naturalistic, observational study. Three nights of sleep were measured using actigraphy, and each 15-s epoch was classified as sleep or wake. Bedside noise was recorded, and each 15-s segment was classified as containing noise or no noise and matched to actigraphy. Participants completed measures of habitual pre-sleep cognitive and somatic arousal and noise sensitivity. Pre-sleep cognitive and somatic arousal levels were negatively associated with subjective–objective total sleep time discrepancy (p < 0.01). There was an association between sleep/wake and noise presence/absence in the first and last 90 min of sleep (p < 0.001). These results indicate that higher levels of habitual pre-sleep arousal are associated with a greater degree of sleep misperception, and even in healthy sleepers, objective sleep is vulnerable to habitual bedside noise.

Survival time discrepancy among under-five-year children of rural parts of Ethiopia.

Background: Ethiopia is ranked as the fifth of heavy under-five death burdened countries with the highest burden in its rural areas. This study aimed to identify the determinants of under-five deaths in rural parts of Ethiopia. Study Design: A population-based cross-sectional study. Methods: The data for this study was extracted from the 2016 Ethiopian Demographic and Health Survey. Descriptive analysis, non-parametric estimation, and Cox proportional hazards regression model were used to examine the determinants of under-five mortality.Results: A total of 7301 under-five eligible children from rural areas were involved in this survey, and 6.5% of the cases were passed away before reaching their fifth birthday. Male children’s death accounted for 59.7% of the death rate in the participants. An estimated median survival time was 31 months [95% CI: 30-32]. About 83% of children’s death occurred among children delivered at home. Cox proportional hazard regression model revealed that gender, delivery-place, family-size, mother’s education, number of children, contraceptive use, and source of drinking water had significant effects on survival time of underfive children. Under-five mortality was significantly fewer in female children (HR = 0.728; 95% CI: 0.606- 0.875, P = 0.001), children delivered at health facilities (HR = 0.738; 95% CI: 0.572-0.951, P = 0.019), and those from secondary and above educated mothers (HR = 0.464; 95% CI: 0.301-0.714, P = 0.001), compared to the reference category.Conclusion: Significant risk factors were associated with under-five mortality in rural areas. Delivering in health facilities, uses of contraceptives, mother’s education, and improvement of infrastructures should be areas of concern to decrease under-five children’s deaths.

Sex Moderates the Relationship between Perceptual-Motor Function and Single-Leg Squatting Mechanics.

To examine the isolated and combined effects of sex and perceptual-motor function on single-leg squatting mechanics in males and females. We employed a cross-sectional design in a research laboratory. Fifty-eight females (22.2 ± 3.5 yrs, 1.60 ± .07 m, 64.1 ± 13.0 kg) and 35 males (23.5 ± 5.0 yrs, 1.80 ± .06m, 84.7 ± 15.3 kg) free from time-loss injury in the six months prior, vertigo, and vestibular conditions participated in this study. Independent variables were sex, perceptual-motor metrics (reaction time, efficiency index, conflict discrepancy), and interaction effects. Dependent variables were peak frontal plane angles of knee projection, ipsilateral trunk flexion, and contralateral pelvic drop during single-leg squatting. After accounting for the sex-specific variance and perceptual-motor function effects on frontal plane squatting kinematics, female sex amplified the associations of: higher reaction time, lower efficiency index, and higher conflict discrepancy with greater right ipsilateral peak trunk lean (R2 = .13; p = .05); higher reaction time, lower efficiency index, and higher conflict discrepancy with decreased right contralateral pelvic drop (R2 = .22; p < .001); higher reaction time and lower conflict discrepancy with greater right frontal plane knee projection angle (R2 = .12; p = .03); and higher reaction time with greater left frontal plane knee projection angle (R2 = .22; p < .001). Female sex amplified the relationship between perceptual-motor function and two-dimensional frontal plane squatting kinematics. Future work should determine the extent to which perceptual-motor improvements translate to safer movement strategies.

Detecting Developers’ Task Switches and Types

Developers work on a broad variety of tasks during their workdays and constantly switch between them. While these task switches can be beneficial, they can also incur a high cognitive burden on developers, since they have to continuously remember and rebuild the task context–the artifacts and applications relevant to the task. Researchers have therefore proposed to capture task context more explicitly and use it to provide better task support, such as task switch reduction or task resumption support. Yet, these approaches generally require the developer to <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">manually</i> identify task switches. Automatic approaches for predicting task switches have so far been limited in their accuracy, scope, evaluation, and the time discrepancy between predicted and actual task switches. In our work, we examine the use of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">automatically</i> collected computer interaction data for detecting developers’ task switches as well as task types. In two field studies–a 4h observational study and a multi-day study with experience sampling–we collected data from a total of 25 professional developers. Our study results show that we are able to use temporal and semantic features from developers’ computer interaction data to detect task switches and types in the field with high accuracy of 84 percent and 61 percent respectively, and within a short time window of less than 1.6 minutes on average from the actual task switch. We discuss our findings and their practical value for a wide range of applications in real work settings.

The effect of the transdiagnostic sleep and circadian intervention (TranS-C) on actigraphic estimates of sleep and rest-activity rhythms in adolescents with an evening circadian preference

BackgroundThis study evaluates whether the Transdiagnostic Sleep and Circadian Intervention for Youth (TranS-C) improves objective sleep and rest-activity rhythms in a sample of youth with an evening circadian preference (ECP). MethodsYouth with an ECP aged 10-18 years were randomized to receive 6 sessions of TranS-C (n = 60) or Psychoeducation (PE; n = 58). For one week prior to beginning treatment and within 2 weeks of completing treatment, participants wore an actiwatch to assess objective sleep and rest-activity rhythms. ResultsAmong TranS-C participants, there were significant pre-post improvements in weeknight total sleep time (TST), weekend TST, and weeknight-weekend discrepancy in TST and sleep offset time. These changes were not significant in PE. There was no significant treatment by time interactions for the sleep or rest-activity outcomes. ConclusionsFor youth with an ECP, TranS-C improves select objective sleep but not rest-activity outcomes, though compared to PE, these benefits did not reach statistical significance.

Smartphone Addiction Proneness Is Associated With Subjective-Objective Sleep Discrepancy in Patients With Insomnia Disorder.

ObjectiveSubjective reports of patients with insomnia often show a discrepancy with their objective assessments of sleep. We aimed to assess subjective-objective sleep discrepancy in subjects with insomnia disorder as well as the psychological factors associated with the discrepancy. MethodsThis study is a secondary analysis of the baseline data of a randomized controlled study on 110 adults aged 18 years to 59 years with insomnia disorder. Subjective reports on sleep and the objective measures acquired by an overnight polysomnography were used to measure the sleep discrepancy. Smartphone Addiction Proneness Scale (SAPS), Center for Epidemiologic Studies Depression Scale (CES-D), beck anxiety inventory (BAI), and Global Assessment of Recent Stress (GARS) were used to evaluate the psychological factors associated with the sleep discrepancy. ResultsMean total sleep time (TST) discrepancy of the participants was -81.65±97.41 minutes. Multivariable logistic regression analyses revealed that age (adjusted OR=1.07, 95% CI=1.01–1.13, p=0.027), years of education (adjusted OR=0.69, 95% CI=0.48–0.91, p=0.017), and smartphone addiction proneness (adjusted OR=1.14, 95% CI=1.04–1.27, p=0.008) were independent predictors of TST misperception. Mean sleep onset latency (SOL) discrepancy of the participants was 41.28±45.01 minutes. Only anxiety was an independent predictor of SOL misperception (adjusted OR=1.16, 95% CI=1.05–1.31, p=0.006). ConclusionThe present study provides empirical evidence to increase our understanding of the various factors that are associated with subjective-objective sleep discrepancy. Screening insomnia patients with smartphone addiction proneness may help predict the potential discrepancy between the patients’ subjective reports and objective measures of sleep duration.

Pure laparoscopic versus open right hepatectomy in living liver donors: bench-surgery time and graft weight discrepancy

Kwangpyo Hong, Suk Kyun Hong, Eui Soo Han, Sanggyun Suh, Su young Hong, Jeong-Moo Lee, YoungRok Choi, Nam-Joon Yi, Kwang-Woong Lee, Kyung-Suk Suh. Korean J Transplant 2021;35:142. https://doi.org/10.4285/ATW2021.OP-1170

A Novel Approach to Assessment of Perceptual-Motor Efficiency and Training-Induced Improvement in the Performance Capabilities of Elite Athletes

Standard clinical assessments of mild traumatic brain injury are inadequate to detect subtle abnormalities that can be revealed by sophisticated diagnostic technology. An association has been observed between sport-related concussion (SRC) and subsequent musculoskeletal injury, but the underlying neurophysiological mechanism is not currently understood. A cohort of 16 elite athletes (10 male, 6 female), which included nine individuals who reported a history of SRC (5 male, 4 female) that occurred between 4 months and 8 years earlier, volunteered to participate in a 12-session program for assessment and training of perceptual-motor efficiency. Performance metrics derived from single- and dual-task whole-body lateral and diagonal reactive movements to virtual reality targets in left and right directions were analyzed separately and combined in various ways to create composite representations of global function. Intra-individual variability across performance domains demonstrated very good SRC history classification accuracy for the earliest 3-session phase of the program (Reaction Time Dispersion AUC = 0.841; Deceleration Dispersion AUC = 0.810; Reaction Time Discrepancy AUC = 0.825, Deceleration Discrepancy AUC = 0.794). Good earliest phase discrimination was also found for Composite Asymmetry between left and right movement directions (AUC = 0.778) and Excursion Average distance beyond the minimal body displacement necessary for virtual target deactivation (AUC = 0.730). Sensitivity derived from Youden's Index for the 6 global factors ranged from 67 to 89% and an identical specificity value of 86% for all of them. Median values demonstrated substantial improvement from the first 3-session phase to the last 3-session phase for Composite Asymmetry and Excursion Average. The results suggest that a Composite Asymmetry value ≥ 0.15 and an Excursion Average value ≥ 7 m, provide reasonable qualitative approximations for clinical identification of suboptimal perceptual-motor performance. Despite acknowledged study limitations, the findings support a hypothesized relationship between whole-body reactive agility performance and functional connectivity among brain networks subserving sensory perception, cognitive decision-making, and motor execution. A complex systems approach appears to perform better than traditional data analysis methods for detection of subtle perceptual-motor impairment, which has the potential to advance both clinical management of SRC and training for performance enhancement.

Characteristics and publication discrepancies of foot & ankle surgery-related clinical trials

BackgroundTrial registration can provide more reliable study designs, however, the final publications are not exempt from bias. This study aimed to show the characteristics of foot & ankle surgery-related clinical trials registered in ClinicalTrials.gov (CTG) and analyze possible risk factors that can lead to discrepancies between the original trial registry and published results. MethodsFoot & ankle surgery-related randomized controlled studies registered in CTG with an anticipated completion date until 2018 were extracted. 157 trials were found eligible for final analysis and corresponding publications were investigated through literature databases. Discrepancies between trial registries and published results were analyzed. Results67.5% of trials were registered whether during the trial period or after completion. 46.5% were funded by industry. 54.8% of trials were reported to be completed. The results of 66 (42%) trials were published in a journal. There was a sample size discrepancy in 57.6%, follow-up time discrepancy in 28.8%, primary outcome discrepancy in 45.5%, and inclusion/exclusion criteria discrepancy in 89.4% of registries. Sample size, inclusion/exclusion criteria discrepancies were significantly more in trials funded by industry (p = 0.024, 0.001, 0.037, respectively). Industry-funded studies reported positive results more frequently (p = 0.011). ConclusionOnly 42% of all registered foot & ankle surgery-related studies had the chance to be published. The majority of studies presented discrepancies in sample size, outcome assessment method, follow-up time, or inclusion/exclusion criteria. Industry-funded studies showed a higher rate of discrepancies and were more inclined towards reporting positive results indicating a risk of bias in assessments. Level of clinical evidenceLevel 3.

Quality assurance data for regional drip-and-ship strategies- gearing up the transfer process

BackgroundStroke patients with large vessel occlusion (LVO) require endovascular therapy (EVT) provided by comprehensive stroke centers (CSC). One strategy to achieve fast stroke symptom ‘onset to treatment’ times (OTT) is the preclinical selection of patients with severe stroke for direct transport to CSC. Another is the optimization of interhospital transfer workflow. Our aim was to investigate the dynamics of the OTT of ‘drip-and-ship’ patients as well as the current ‘door-in-door-out’ time (DIDO) and its determinants at representative regional German stroke units.MethodsWe determined the numbers of all EVT treatments, ‘drip-and-ship’ and ‘direct-to-center’ patients and their median OTT from the mandatory quality assurance registry of the federal state of Hesse, Germany (2012–2019). Additionally, we captured process time stamps from primary stroke centers (PSC) in a consecutive registry of patients referred for EVT in our regional stroke network over a 3 months period.ResultsAlong with an increase of the EVT rate, the proportion of drip-and-ship patients grew steadily from 19.4% in 2012 to 31.3% in 2019. The time discrepancy for the median OTT between ‘drip-and-ship’ and ‘direct-to-center’ patients continuously declined from 173 to 74 min. The largest share of the DIDO (median 92, IQR 69–110) is spent with the organization of EVT and consecutive patient transfer.Conclusions‘Drip-and-ship’ patients are an important and growing proportion of stroke patients undergoing EVT. The discrepancy in OTT for EVT between ‘drip-and-ship’ and ‘direct-to-center’ patients has been reduced considerably. Further optimization of the DIDO primarily aiming at the processes after the detection of LVO is urgently needed to improve stroke patient care.

Excess returns in Public-Private Partnerships: Do governments pay too much?

We study the optimal design of Public-Private Partnerships (PPPs) when there is unobservable action on the private party's side. We show that if the private party does not have negotiating power over the project's surplus, then no inefficient delays are attributable to the moral hazard issue. However, if the private party has negotiating power, then the first-best timing is not guaranteed. The time discrepancy is shown to be costly in terms of overall project efficiency. The explicit consideration of the private party's negotiating power can explain empirical evidence that private parties in PPPs tend to reap excess returns. These results are discussed in light of the COVID-19 pandemic and its implications for PPPs.

Population dynamic regulators in an empirical predator-prey system

Capelin (Mallotus villosus) is a short-lived (1–4 years) fish species, that plays a crucial role by dominating the intermediate trophic level in the Barents Sea. Several episodes of extreme biomass decline (collapse) have been observed during the last three decades. We postulate that these collapses might be regulated by food availability (bottom-up effect) and/or by time discrepancy between capelin feeding and abundance of its prey (match-mismatch hypothesis). This paper investigates our postulate using a model consisting of a set of coupled differential equations to describe the predator-prey system, with a single delay term, τ, in description of the predator dynamics. We derive theoretical conditions on τ, as well as determine how changes in these conditions define different stability regimes of the system. Unconstrained optimization is used to calculate optimal model parameters by fitting the predator-prey model to empirical data. The optimization results are combined with those from the theoretical analysis, to make inference about the empirical system stability. Our results show that Hopf bifurcation occurs in the predatory-prey system when τ exceeds a theoretically derived value τ∗>0. This value represents the critical time for prey availability in advance of the optimal predator growth period.Set into an ecological context, our findings provide mathematical evidence for validity of the match-mismatch hypothesis and a bottom-up effect for capelin.

APPROACHES TO AGRICULTURAL ENTERPRISES POSITIONING

With the development of market economic relations and the intensification of competition in Ukraine, the problem of adequate positioning of enterprises among competitors, as well as in the consumers` minds becomes relevant. The author summarizes scientific approaches of foreign and domestic scientists to the interpretation of the concept of "positioning", which are reflected in the following: F. Kotler (positioning as a way of identifying goods), J. Trout, E. Reiss (as a certain position of the enterprise among competing goods), Belyaeva N.S. (as an element of the enterprise strategic management system). Three basic components to understanding the essence of positioning are generalized and allocated: positioning as a concept that defines the ideological aspect in its definition (ideas and views), which are the basis of the enterprise product proposal; positioning as a strategy that involves the development of a competitive position of the enterprise product and the relevant marketing complex; positioning as a set of actions that characterizes a set of measures, specific ways to convey the position to the target segment in the implementation of marketing programs; so it is a set of tools to help forming a brand image that should strongly differ from competitors. Due to the fact that the agricultural component is important to the Ukrainian economy development, it is necessary to ensure the effective positioning of agricultural enterprises in foreign markets, which is the source of their sustainable competitive advantage. The opinions of Ukrainian scientists on the agricultural enterprises products positioning were summarized: Kozak L.V., who proposes strategies for the agricultural enterprises development; Kosharna P.S., who offers strategic tools for the agricultural enterprises; Artyukhova K.V. and Bondarenko V.V., who substantiate the necessary market position of agricultural enterprises. Approaches and factors for positioning of agricultural products that should be taken into account in the foreign economic activity of enterprises such as planning, staff, practice, partners that can strengthen opportunities, positioning, protection are analyzed. Peculiarities of agricultural enterprises products positioning were determined: production seasonality, high level of natural and climatic conditions dependence, role and value of products, variety of management organizational forms, time discrepancy in finished products growing and manufacturing, level of state participation in agro-industrial complex development. The author has formed a structural and logistical scheme of agricultural enterprises product positioning, which has the following main elements: purpose, means, conditions of activity, support (including the development of enterprise products positioning strategy) and marketing tools. The main marketing tools that must be used in positioning the products of agricultural enterprises include: the type of product, its quality, functional properties, type of packaging, guarantees; price formation conditions; logistics sales channels used in the delivery of products to the customer; products promotion; qualification of the personnel carrying out marketing support of agricultural enterprises production.

Comparison of tibial plateau fracture surgical outcomes between young and elderly patients: are outcomes really poorer in the elderly?

Several studies have reported that total knee arthroplasty (TKA) is a suitable solution to treat elderly patients with complex tibial plateau fractures. The purpose of the present study was to compare surgical treatment outcomes after open reduction internal fixation (ORIF) between elderly and younger patients. We reviewed patients with plateau fracture (OTA/AO classification types 41B and 41C) who underwent ORIF at two academic trauma centers between November 2006 and October 2019. Of the 341 patients, 76 were ultimately included in the younger group (< 60years old) and 77 in the elderly group (≥ 60years). The average follow-up was 24months (range 12-96months). The primary outcome was any common complication of plateau fracture, namely post-traumatic arthritis and alignment change. Conversion to TKA, Reduction loss, coronal malalignment, non-union, union time, infection, and limb length discrepancy (LLD) were also assessed. The elderly group had a significantly higher prevalence of diabetes, but there were no other significant differences between the groups in terms of patient demographics, fracture characteristics, and operation characteristics. We detected no differences between the groups in terms of post-traumatic arthritis (p = 0.216), alignment change (p = 0.093), conversion to TKA (p = 0.681), reduction loss (p = 0.079), coronal malalignment (p = 0.484), non-union rate (p = 0.719), infection (p = 0.063), LLD (p = 0.154), or time to union (p = 0.513). Logistic regression analysis revealed that age > 60years was not associated with treatment failure, defined as either post-traumatic arthritis greater than grade II or non-union (p = 0.468). OTA/AO classification type 41C2 (p = 0.019), type 41C3 (p = 0.008), and malreduction (p = 0.050) were significant risk factors for failure. Age ≥ 60years is not an independent risk factor of poor radiographic outcome and high complication rate in tibial plateau fractures. This indicates that ORIF is still a good solution to treat elderly patients, similar to their younger counterparts.

Determination of variation uncertainty in runoff time series at multi-temporal scales

Abstract In order to survey the possible periodic, uncertainty and common features in runoff with multi-temporal scales, the empirical mode decomposition (EMD) method combined with the set pair analysis (SPA) method was applied, with data observed at Zhangjiashan hydrological station. The results showed that the flood season and annual runoff time series consisted of four intrinsic mode function (IMF) components, and the non-flood season time series exhibited three IMF components. Moreover, based on the different coupled set pairs from the time series, the identity, discrepancy, and contrary of different periods at multi-temporal scales were determined by the SPA method. The degree of connection μ between the flood season and annual runoff periods were the highest, with 0.94, 0.77, 0.7 and 0.73, respectively, and the μ between the flood periods and the non-flood periods were the lowest, with 0.66, 0.46, 0.24 and 0.24, respectively. Third, the maximum μ of each SPA appeared in the first mode function. In general, the different extractive periods decomposed by the EMD method reflected the average state of Jinghe River. Results also verified that runoff suffered from seasonal and periodic fluctuations, and fluctuations in the short-term corresponded to the most important variable. Therefore, the conclusions drawn in this study can improve water resources regulation and planning.

Generalizing HMMs to Continuous Time for Fast Kinetics: Hidden Markov Jump Processes

The hidden Markov model (HMM) is a framework for time series analysis widely applied to single-molecule experiments. Although initially developed for applications outside the natural sciences, the HMM has traditionally been used to interpret signals generated by physical systems, such as single molecules, evolving in a discrete state space observed at discrete time levels dictated by the data acquisition rate. Within the HMM framework, transitions between states are modeled as occurring at the end of each data acquisition period and are described using transition probabilities. Yet, whereas measurements are often performed at discrete time levels in the natural sciences, physical systems evolve in continuous time according to transition rates. It then follows that the modeling assumptions underlying the HMM are justified if the transition rates of a physical process from state to state are small as compared to the data acquisition rate. In other words, HMMs apply to slow kinetics. The problem is, because the transition rates are unknown in principle, it is unclear, a priori, whether the HMM applies to a particular system. For this reason, we must generalize HMMs for physical systems, such as single molecules, because these switch between discrete states in “continuous time”. We do so by exploiting recent mathematical tools developed in the context of inferring Markov jump processes and propose the hidden Markov jump process. We explicitly show in what limit the hidden Markov jump process reduces to the HMM. Resolving the discrete time discrepancy of the HMM has clear implications: we no longer need to assume that processes, such as molecular events, must occur on timescales slower than data acquisition and can learn transition rates even if these are on the same timescale or otherwise exceed data acquisition rates.

Federated Learning With a Drone Orchestrator: Path Planning for Minimized Staleness

In this paper, we investigate the problem of scheduling transmissions for spatially scattered nodes that contribute to a collaborative federated learning (FL) algorithm via wireless links provided by a drone. In the considered system, the drone acts as an orchestrator, coordinating the transmissions and the learning schedule within a predefined deadline. The actual schedule is reflected in a planned path: as the drone traverses it, it controls the distance and thereby the data rate to each node. Hence, the model is structured such that the drone orchestrator uses the path (trajectory) as its only tool to achieve fairness in terms of learning <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">staleness</i> , which reflects the learning time discrepancy among the nodes. Using the number of learning epochs performed at each learner as a performance indicator, we combine the average number of epochs computed and staleness into a balanced optimization criterion that is agnostic to the underlying FL implementation. We consider two methods for solving the complex trajectory planning optimization problem for static nodes: (1) successive convex programming (SCP) and (2) deep reinforcement learning (RL). Considering the proposed criterion, both methods are compared in three specific scenarios with few nodes. The results show that drone-orchestrated FL outperforms an immobile deployment by providing improvements in the range of 57% to 87.7%. Additionally, RL-guided trajectories are generally superior to SCP provided ones for complex node arrangements.