Tag: statistics

Proc Natl Acad Sci U S A. 2022 Nov;119(44):e2203468119. doi: 10.1073/pnas.2203468119. Epub 2022 Oct 24.

ABSTRACT

Sea ice decline in the North Atlantic and Nordic Seas has been proposed to contribute to the repeated abrupt atmospheric warmings recorded in Greenland ice cores during the last glacial period, known as Dansgaard-Oeschger (D-O) events. However, the understanding of how sea ice changes were coupled with abrupt climate changes during D-O events has remained incomplete due to a lack of suitable high-resolution sea ice proxy records from northwestern North Atlantic regions. Here, we present a subdecadal-scale bromine enrichment (Br_enr) record from the NEEM ice core (Northwest Greenland) and sediment core biomarker records to reconstruct the variability of seasonal sea ice in the Baffin Bay and Labrador Sea over a suite of D-O events between 34 and 42 ka. Our results reveal repeated shifts between stable, multiyear sea ice (MYSI) conditions during cold stadials and unstable, seasonal sea ice conditions during warmer interstadials. The shift from stadial to interstadial sea ice conditions occurred rapidly and synchronously with the atmospheric warming over Greenland, while the amplitude of high-frequency sea ice fluctuations increased through interstadials. Our findings suggest that the rapid replacement of widespread MYSI with seasonal sea ice amplified the abrupt climate warming over the course of D-O events and highlight the role of feedbacks associated with late-interstadial seasonal sea ice expansion in driving the North Atlantic ocean-climate system back to stadial conditions.

PMID:36279448 | DOI:10.1073/pnas.2203468119

Proc Natl Acad Sci U S A. 2022 Nov;119(44):e2208183119. doi: 10.1073/pnas.2208183119. Epub 2022 Oct 24.

ABSTRACT

The origin of methylmercury in pelagic fish remains unclear, with many unanswered questions regarding the production and degradation of this neurotoxin in the water column. We used mercury (Hg) stable isotope ratios of marine particles and biota to elucidate the cycling of methylmercury prior to incorporation into the marine food web. The Hg isotopic composition of particles, zooplankton, and fish reveals preferential methylation of Hg within small (< 53 µm) marine particles in the upper 400 m of the North Pacific Ocean. Mass-dependent Hg isotope ratios (δ²⁰²Hg) recorded in small particles overlap with previously estimated δ²⁰²Hg values for methylmercury sources to Pacific and Atlantic Ocean food webs. Particulate compound specific isotope analysis of amino acids (CSIA-AA) yield δ¹⁵N values that indicate more-significant microbial decomposition in small particles compared to larger particles. CSIA-AA and Hg isotope data also suggest that large particles (> 53 µm) collected in the equatorial ocean are distinct from small particles and resemble fecal pellets. Additional evidence for Hg methylation within small particles is provided by a statistical mixing model of even mass-independent (Δ²⁰⁰Hg and Δ²⁰⁴Hg) isotope values, which demonstrates that Hg within near-surface marine organisms (0-150 m) originates from a combination of rainfall and marine particles. In contrast, in meso- and upper bathypelagic organisms (200-1,400 m), the majority of Hg originates from marine particles with little input from wet deposition. The occurrence of methylation within marine particles is supported further by a correlation between Δ²⁰⁰Hg and Δ¹⁹⁹Hg values, demonstrating greater overlap in the Hg isotopic composition of marine organisms with marine particles than with total gaseous Hg or wet deposition.

PMID:36279440 | DOI:10.1073/pnas.2208183119

Proc Natl Acad Sci U S A. 2022 Nov 8;119(45):e2121092119. doi: 10.1073/pnas.2121092119. Epub 2022 Oct 24.

ABSTRACT

Animals migrate in response to seasonal environments, to reproduce, to benefit from resource pulses, or to avoid fluctuating hazards. Although climate change is predicted to modify migration, only a few studies to date have demonstrated phenological shifts in marine mammals. In the Arctic, marine mammals are considered among the most sensitive to ongoing climate change due to their narrow habitat preferences and long life spans. Longevity may prove an obstacle for species to evolutionarily respond. For species that exhibit high site fidelity and strong associations with migration routes, adjusting the timing of migration is one of the few recourses available to respond to a changing climate. Here, we demonstrate evidence of significant delays in the timing of narwhal autumn migrations with satellite tracking data spanning 21 y from the Canadian Arctic. Measures of migration phenology varied annually and were explained by sex and climate drivers associated with ice conditions, suggesting that narwhals are adopting strategic migration tactics. Male narwhals were found to lead the migration out of the summering areas, while females, potentially with dependent young, departed later. Narwhals are remaining longer in their summer areas at a rate of 10 d per decade, a similar rate to that observed for climate-driven sea ice loss across the region. The consequences of altered space use and timing have yet to be evaluated but will expose individuals to increasing natural changes and anthropogenic activities on the summering areas.

PMID:36279424 | DOI:10.1073/pnas.2121092119

Anesth Analg. 2022 Oct 24. doi: 10.1213/ANE.0000000000006219. Online ahead of print.

ABSTRACT

BACKGROUND: Although sugammadex is well known for its use in reducing the incidence of residual neuromuscular blockade, this has not always been translated to improved clinical measures of postoperative respiratory muscle strength. Expiratory muscles play an important role in airway clearance and inspiratory muscle capacity augmentation, yet they have not been well studied. Therefore, we tested the hypothesis on whether sugammadex could enhance expiratory muscle strength recovery more completely than neostigmine in the immediate postextubation period.

METHODS: Adult patients having microlaryngeal surgery under total intravenous anesthesia were randomized to receive sugammadex or neostigmine. The thickening fraction of internal oblique abdominal muscle (TFIO) and diaphragm excursion, respectively, reflecting expiratory and inspiratory muscle strength, were measured via ultrasonography at 3 time points: before induction (baseline), train-of-four ratio (TOFR) recovery to 0.9, and 30 minutes after postanesthesia care unit (PACU) arrival. The primary outcome was the change in TFIO from baseline to TOFR ≥0.9. The postoperative changes of diaphragm excursion from baseline, incidences of TFIO and diaphragm excursion returning to baseline levels, and the time from TOFR 0.9 to 0.95 and 1 were also measured.

RESULTS: Among 58 patients, a significant difference in the change in TFIO from baseline to TOFR ≥0.9 between the sugammadex and neostigmine groups was observed: mean ± standard deviation, 9% ± 6% vs 16% ± 9%; difference in means: -6% (95% confidence interval [CI], -10 to -2); and adjusted P =.005 (adjusting for imbalanced variables between 2 groups). Sugammadex resulted in smaller changes in diaphragm excursion from baseline to TOFR ≥0.9 compared with neostigmine: difference in means: -0.83 cm (99.4% CI, -1.39 to -0.28 cm; Bonferroni-corrected P < .001). After 30 minutes in the postanesthesia care unit (PACU),33% of patients reversed with sugammadex versus 14% of those receiving neostigmine reached baseline TFIO levels (99.4% CI, -14 to 52; Bonferroni-corrected P > .999). The incidences of TFIO and diaphragm excursion returning to baseline were relatively low (<40%) in both groups despite TOFR reaching 1. The median time from TOFR of 0.9 to 0.95 and to 1 among patients receiving sugammadex was 7 and 10× faster than those receiving neostigmine (0.3 vs 2 minutes, Bonferroni-corrected P = .003; 0.5 vs 5.3 minutes, Bonferroni-corrected P < .001, respectively).

CONCLUSIONS: Sugammadex provides a more complete recovery of expiratory muscle strength than neostigmine at TOFR ≥0.9. Our data suggest that the respiratory muscle strength might still be impaired despite TOFR reaching 1.

PMID:36279410 | DOI:10.1213/ANE.0000000000006219

J Phys Chem B. 2022 Oct 24. doi: 10.1021/acs.jpcb.2c04347. Online ahead of print.

ABSTRACT

Nanoconfined fluids exhibit remarkably different thermodynamic behavior compared to the bulk phase. These confinement effects render predictions of thermodynamic quantities of nanoconfined fluids challenging. In particular, confinement creates a spatially varying density profile near the wall that is primarily responsible for adsorption and capillary condensation behavior. Significant fluctuations in thermodynamic quantities, inherent in such nanoscale systems, coupled to strong fluid-wall interactions give rise to this near-wall density profile. Empirical models have been proposed to explain and model these effects, yet no first-principles based formulation has been developed. We present a statistical mechanics framework that embeds such a coupling to describe the effect of the fluid-wall interaction in amplifying the near-wall density behavior for compressible gases at elevated pressures such as pressurized methane in confinement. We show that the proposed theory predicts accurately the adsorbed layer thickness as obtained with small-angle neutron scattering measurements. Furthermore, the predictions of density under confinement from the proposed theory are shown to be in excellent agreement with available experimental and atomistic simulations data for a range of temperatures for nanoconfined methane. While the framework is presented for evaluating the near-wall density, owing to its rigorous foundation in statistical mechanics, the proposed theory can also be generalized for predicting phase-transition and nonequilibrium transport of nanoconfined fluids.

PMID:36279403 | DOI:10.1021/acs.jpcb.2c04347

Environ Sci Technol. 2022 Oct 24. doi: 10.1021/acs.est.2c05872. Online ahead of print.

ABSTRACT

The benchmark dose (BMD) methodology has significantly advanced the practice of dose-response analysis and created substantial opportunities to enhance the plausibility of BMD estimation by synthesizing dose-response information from different sources. Particularly, integrating existing toxicological information via prior distribution in a Bayesian framework is a promising but not well-studied strategy. The study objective is to identify a plausible way to incorporate toxicological information through informative prior to support BMD estimation using dichotomous data. There are four steps in this study: determine appropriate types of distribution for parameters in common dose-response models, estimate the parameters of the determined distributions, investigate the impact of alternative strategies of prior implementation, and derive endpoint-specific priors to examine how prior-eliciting data affect priors and BMD estimates. A plausible distribution was estimated for each parameter in the common dichotomous dose-response models using a general database. Alternative strategies for implementing informative prior have a limited impact on BMD estimation, but using informative prior can significantly reduce uncertainty in BMD estimation. Endpoint-specific informative priors are substantially different from the general one, highlighting the necessity for guidance on prior elicitation. The study developed a practical way to employ informative prior and laid a foundation for advanced Bayesian BMD modeling.

PMID:36279400 | DOI:10.1021/acs.est.2c05872

Vopr Kurortol Fizioter Lech Fiz Kult. 2022;99(5):28-36. doi: 10.17116/kurort20229905128.

ABSTRACT

Secondary focal lesions of the musculoskeletal system that occur with residual brucellosis are characterized by a variety of localizations and simultaneous damage to several groups of joints, a deterioration in the quality of life and a high percentage of disability in people of working age. At present, there are many different schemes for the treatment and rehabilitation of developed residual brucellosis, in which, in addition to the “basic” course, including systemic anti-inflammatory therapy, much attention is paid to physiotherapeutic procedures, but the choice of the most effective treatment tactics remains an unresolved problem.

PURPOSE OF THE STUDY: To determine the effectiveness of the use of options for non-drug methods of treatment in the complex rehabilitation of patients with residual brucellosis with lesions of musculoskeletal system.

MATERIAL AND METHODS: Study included 140 patients treated for osteoarthritis of brucellosis etiology, who were divided into three groups matched by age, gender, average duration and stage of the disease, place of residence. Patients of all groups received standard medical treatment and different sets of physiotherapeutic procedures: in the 1st group (45 patients) – electrophoresis of novocaine on the knee joints, therapeutic massage of the cervical-collar zone; in the 2nd group (45 patients) – magnetotherapy on the area of the knee joints, sinusoidal modulated currents (SMC) on the shoulder joints, decimeter wave therapy of the lumbosacral zone (DMW-therapy); in the 3rd group (50 patients) – magnetic laser therapy on the shoulder, elbow, knee joints, therapeutic massage of the lumbosacral zone. Complaints, clinical symptoms, goniometry results, and blood parameters were assessed: ESR, C-reactive protein, fibrinogen, before the start of treatment, immediately after the course of rehabilitation, and after 6 and 12 months. At the same time, testing was carried out according to the SF-36 Health Status Survey questionnaire to monitor the quality of life.

RESULTS: The applied scheme of drug treatment in combination with magnetic laser therapy and therapeutic massage in the 3rd group made it possible to achieve a significant reduction in arthralgic syndrome, a statistically significant increase in the range of motion in the joints, positive dynamics of laboratory data and an improvement in the psychological state and quality of life of patients compared to other observation groups.

CONCLUSION: The results of the study indicate the high efficiency of magnetic laser therapy in the complex treatment of patients with residual brucellosis with lesions of the musculoskeletal system.

PMID:36279374 | DOI:10.17116/kurort20229905128

IEEE Trans Vis Comput Graph. 2022 Oct 24;PP. doi: 10.1109/TVCG.2022.3216712. Online ahead of print.

ABSTRACT

Image-warping, a per-pixel deformation of one image into another, is an essential component in immersive visual experiences such as virtual reality or augmented reality. The primary issue with image warping is disocclusions, where occluded (and hence unknown) parts of the input image would be required to compose the output image. We introduce a new image warping method, Metameric image inpainting – an approach for hole-filling in real-time with foundations in human visual perception. Our method estimates image feature statistics of disoccluded regions from their neighbours. These statistics are inpainted and used to synthesise visuals in real-time that are less noticeable to study participants, particularly in peripheral vision. Our method offers speed improvements over the standard structured image inpainting methods while improving realism over colour-based inpainting such as push-pull. Hence, our work paves the way towards future applications such as depth image-based rendering, 6-DoF 360 rendering, and remote render-streaming.

PMID:36279345 | DOI:10.1109/TVCG.2022.3216712

IEEE Trans Neural Netw Learn Syst. 2022 Oct 24;PP. doi: 10.1109/TNNLS.2022.3213522. Online ahead of print.

ABSTRACT

Real-world data usually present long-tailed distributions. Training on imbalanced data tends to render neural networks perform well on head classes while much worse on tail classes. The severe sparseness of training instances for the tail classes is the main challenge, which results in biased distribution estimation during training. Plenty of efforts have been devoted to ameliorating the challenge, including data resampling and synthesizing new training instances for tail classes. However, no prior research has exploited the transferable knowledge from head classes to tail classes for calibrating the distribution of tail classes. In this article, we suppose that tail classes can be enriched by similar head classes and propose a novel distribution calibration (DC) approach named as label-aware DC (). transfers the statistics from relevant head classes to infer the distribution of tail classes. Sampling from calibrated distribution further facilitates rebalancing the classifier. Experiments on both image and text long-tailed datasets demonstrate that significantly outperforms existing methods. The visualization also shows that provides a more accurate distribution estimation.

PMID:36279339 | DOI:10.1109/TNNLS.2022.3213522

IEEE Trans Neural Netw Learn Syst. 2022 Oct 24;PP. doi: 10.1109/TNNLS.2022.3213518. Online ahead of print.

ABSTRACT

The finite inverted beta mixture model (IBMM) has been proven to be efficient in modeling positive vectors. Under the traditional variational inference framework, the critical challenge in Bayesian estimation of the IBMM is that the computational cost of performing inference with large datasets is prohibitively expensive, which often limits the use of Bayesian approaches to small datasets. An efficient alternative provided by the recently proposed stochastic variational inference (SVI) framework allows for efficient inference on large datasets. Nevertheless, when using the SVI framework to address the non-Gaussian statistical models, the evidence lower bound (ELBO) cannot be explicitly calculated due to the intractable moment computation. Therefore, the algorithm under the SVI framework cannot directly use stochastic optimization to optimize the ELBO, and an analytically tractable solution cannot be derived. To address this problem, we propose an extended version of the SVI framework with more flexibility, namely, the extended SVI (ESVI) framework. This framework can be used in many non-Gaussian statistical models. First, some approximation strategies are applied to further lower the ELBO to avoid intractable moment calculations. Then, stochastic optimization with noisy natural gradients is used to optimize the lower bound. The excellent performance and effectiveness of the proposed method are verified in real data evaluation.

PMID:36279334 | DOI:10.1109/TNNLS.2022.3213518