Tag: statistics

JCO Oncol Pract. 2022 Oct 10:OP2200300. doi: 10.1200/OP.22.00300. Online ahead of print.

ABSTRACT

PURPOSE: Individuals diagnosed with cancer age between 15 and 39 years (adolescents and young adults [AYAs]) have not seen improvement in survival compared with children or older adults; clinical trial accrual correlates with survival. Unique unmet needs among AYAs related to psychosocial support and fertility preservation (FP) are associated with health-related quality of life.

METHODS: We enhanced existing structures and leveraged faculty/staff across pediatric/adult oncology to create novel teams focused on AYA (age 15-39 years) care at a single center, with minimal dedicated staff and no change to revenue streams. We aimed to influence domains shown to drive survival and health-related quality of life: clinical trial enrollment, physician/staff collaboration, psychosocial support, and FP. We captured metrics 3 months after patients presented to the institution and compared them before/after Program implementation using descriptive statistics.

RESULTS: Among 139 AYAs (age 15-39 years) from the pre-Program era (January 2016-February 2019: adult, n = 79; pediatric, n = 60), and 279 from the post-Program era (February 2019-March 2022: adult, n = 215; pediatric, n = 64), there was no change in clinical trial enrollment(P ≥ .3), whereas there was an increase in the proportion of AYAs referred for supportive care and psychology (pediatric: P ≤ .02; adult: P ≤ .001); whose oncologists discussed FP (pediatric: 15% v 52%, P < .0001; adult: 37% v 50%, P = .0004); and undergoing FP consults (pediatric: 8% v39%, P < .0001; adult 23% v 38%, P = .02).

CONCLUSION: This team-based framework has effected change in most targeted domains. To affect all domains and design optimal interventions, it is crucial to understand patient-level and facility-level barriers/facilitators to FP and clinical trial enrollment.

PMID:36215685 | DOI:10.1200/OP.22.00300

Eur J Public Health. 2022 Oct 10:ckac115. doi: 10.1093/eurpub/ckac115. Online ahead of print.

ABSTRACT

BACKGROUND: Effectiveness of tobacco taxation can be undermined through smokers applying price-minimizing behaviours rather than quitting or reducing consumption. Common price-minimizing strategies are buying cheaper tobacco [discount brands or roll-your-own (RYO) tobacco], bulk buying and cross-border purchasing. This study analyses trends in and factors associated with such behaviours in four European countries from 2006 to 2020.

METHODS: Data came from adult smokers participating in the International Tobacco Control (ITC) Surveys conducted between 2006 and 2020 in England (9 waves, n = 768-4149), France (4 waves, n = 1415-1735), Germany (5 waves, n = 513-1515) and the Netherlands (10 waves, n = 1191-2177). Country-specific generalized estimating equation regression models were fit to assess trends in smoking RYO tobacco, discount brands, bulk buying and cross-border purchasing within the European Union.

RESULTS: Buying discount brands or RYO tobacco was the most common strategy in all countries, except France. Except for buying discount brands, estimates of price-minimizing behaviours were highest in France (2019: RYO = 27.2%, discount brands = 17.3%, bulk buying = 34.1%, cross-border purchasing = 34.2%), and lowest in Germany (2018: RYO = 18.6%, discount brands = 43.7%, bulk buying = 8.0%, cross-border purchasing = 9.8%). Direction and magnitude of trends differed by country, and behaviour. Young smokers were less likely to buy in bulk. Low-income and low-education smokers were more likely to purchase RYO tobacco or discount brands. The association with discount brands was not found for French low-income smokers.

CONCLUSIONS: Smoking cheaper tobacco is the most prevalent price-minimizing strategy in three countries (England, Germany and Netherlands), and more prevalent among low-income individuals. Harmonizing prices across products and countries would reduce switching to cheaper tobacco.

PMID:36215655 | DOI:10.1093/eurpub/ckac115

J Opt Soc Am A Opt Image Sci Vis. 2022 Aug 1;39(8):1360-1370. doi: 10.1364/JOSAA.461542.

ABSTRACT

Metrics of color-difference formula improvement (i.e., standardized residual sum of squares and Pearson product moment correlation) are shown to convey the same information. Furthermore, each metric has two computational forms that assume different linear data models, specifically, with or without an ordinate intercept. It is essential to choose a computational form that matches the data model. We recommend explicitly declaring whether or not the data have been centered, i.e., by subtracting the mean value from each datum, to match the intercept-free data model. Statistical testing of the metrics assumes independent, normally distributed randomness of residuals from the data model, and homogeneous variance. Procedures consistent with these assumptions include robust statistical tests, homogenizing data transformations, and meta-analysis.

PMID:36215579 | DOI:10.1364/JOSAA.461542

J Nucl Med. 2022 Sep 2:jnumed.122.264424. doi: 10.2967/jnumed.122.264424. Online ahead of print.

ABSTRACT

Objective: To determine the negative predictive value (NPV) of a 12-14 week post-treatment PET/CT for 2-year progression-free survival (PFS) and locoregional control (LRC) in patients with p16-positive locoregionally advanced oropharyngeal cancer (LA-OPC). Study was a secondary endpoint in NRG-HN002, a non-comparative phase II trial in p16-positive LA-OPC, stage T1-T2, N1-N2b or T3, N0-N2b (AJCC, 7th ed.) and ≤ 10 pack-year smoking. Patients were randomized in a 1:1 ratio to reduced-dose IMRT with or without cisplatin. Methods: PET/CT scans were reviewed centrally. Tumor response evaluations for the primary site, right neck, and left neck were carried out using a 5-point ordinal scale (Hopkins Criteria). Overall scores were then assigned as ‘Negative,’ Positive,’ or ‘Indeterminate’. Patients with a ‘Negative’ score for all three evaluation sites were given an overall score of ‘Negative.’ The hypotheses were NPV for PFS and LRC at two years post-treatment ≤ 90% vs >90% (1-sided alpha 0.10). Results: There were 316 patients enrolled, of whom 306 were randomized and eligible. Of these, 131 (42.8%) patients consented to a post-therapy PET/CT, and 117 (89.3%) patients were eligible for PET/CT analysis. The median time from the end of treatment to PET/CT scan was 94 days (range 52-139). Estimated 2-year PFS and LRC rates in the analysis subgroup were 91.3% (95% confidence interval CI [84.6, 95.8%]) and 93.8% (95% CI [87.6, 97.5%]), respectively. Post-treatment scans were negative for residual tumor for 115 patients (98.3%) and positive for two patients (1.7%). NPV for 2-year PFS was 92.0% (90% lower confidence bound [LCB] 87.7%; P = 0.30) and for LRC was 94.5% (90% LCB 90.6%; P = 0.07). Conclusion: In the context of deintensification with reduced-dose radiation, the NPV of a 12-14 week post-therapy PET/CT for 2-year LRC is estimated to be > 90%, similar to that reported for patients receiving standard chemoradiation. However, there is insufficient evidence to conclude that the NPV is > 90% for PFS.

PMID:36215572 | DOI:10.2967/jnumed.122.264424

J Opt Soc Am A Opt Image Sci Vis. 2022 Oct 1;39(10):1857-1865. doi: 10.1364/JOSAA.470040.

ABSTRACT

A narrow beam propagating through the disordered optical fiber first undergoes diffusive broadening, until its width becomes comparable to the localization length. The study of numerical algorithms and statistical methods in the simulation analysis process of disordered optical fibers demonstrates that the influence of polarization characteristics and transverse grids on calculation errors is critical for statistical numerical simulation in disordered systems. We performed a detailed numerical analysis of the effect of different design parameters in disordered fibers on the localization effect-that is, the localization length, including the refractive index contrast, feature size, and fill-fraction. The results show that the optimal fill-fraction is 50%, and that higher refractive index contrast and larger feature size relative to the wavelength both result in a smaller effective beam width. Finally, numerical evidence is also provided that optical images can be transported via transverse Anderson localization.

PMID:36215558 | DOI:10.1364/JOSAA.470040

J Opt Soc Am A Opt Image Sci Vis. 2022 Jun 1;39(6):B65-B77. doi: 10.1364/JOSAA.450595.

ABSTRACT

Predicting the quality of natural images without using a reference image has always been a challenging task. Numerous approaches have been proposed in the past, but they mainly focused on spatial and frequency domain degradations like blur, noise, and compression. Image quality metrics (IQMs) in literature perform with quite a high accuracy for such types of degraded images. However, their performances are not good on the images modified in the color domain. In this study, psychophysical experiments were conducted to assess the quality of the color domain images. A new dataset was developed for this purpose. Additionally, a second dataset consisting of color domain modified images from the three previously published datasets were used in the psychophysical experiments. The newly developed dataset was then used to develop three IQMs based on absolute values, relative values, and statistical analysis of image color appearance attributes. Their performances were then evaluated together with five spatial domain IQMs from the literature using cross-database evaluation methodology. The results showed that the color-domain IQMs outperformed the other models. The absolute and relative attributes-based models, when combined, achieved the best performance. The present results suggest that more effort is needed to improve the performance of color domain IQMs for image quality estimation.

PMID:36215544 | DOI:10.1364/JOSAA.450595

J Opt Soc Am A Opt Image Sci Vis. 2022 Jun 1;39(6):1104-1110. doi: 10.1364/JOSAA.457223.

ABSTRACT

Color theory is based on the exclusive activation of cones. However, since the discovery of melanopsin expressing cells in the human retina, evidence of its intrusion in brightness and color vision is increasing. We aimed to assess if differences between peripheral or large field and foveal color matches can be accounted for by melanopsin activation or rod intrusion. Photopic color matches by young observers showed that differences between extrafoveal and foveal results cannot be explained by rod intrusion. Furthermore, statistical analyses on existing color-matching functions suggest a role of melanopsin activation, particularly, in large field S fundamentals.

PMID:36215541 | DOI:10.1364/JOSAA.457223

J Opt Soc Am A Opt Image Sci Vis. 2022 Jun 1;39(6):1014-1024. doi: 10.1364/JOSAA.451074.

ABSTRACT

In an actual scene, underwater optical wireless communication (UOWC) transceivers may not be perfectly aligned from the start due to imprecise operation or disturbances such as water flow, and thus outdated pointing errors can no longer reliably reflect precise channel conditions. In this paper, for the first time, to our knowledge, we formulate a comprehensive misalignment errors model by taking into account both random jitter and initial misalignment errors. Furthermore, we deduce an effective receiving area due to the deflection of the receiver with three rotation angles in three-dimensional space. Moreover, we also apply the above findings to the composite fading channel model, which is more accurate and practical than the previous. Finally, we develop closed-form results for the bit error rate (BER) in terms of the Meijer G-function of UOWC systems. The performance is also analyzed by the multiplicative statistical channel model. Results demonstrate that comprehensive misalignment errors exacerbate performance degradation in terms of both average BER and outage probability, compared to pointing errors considering only random jitter. It indicates that the initial misalignment errors are not negligible, and analyzing scenes with comprehensive misalignment errors is of great importance in practice.

PMID:36215531 | DOI:10.1364/JOSAA.451074

Proc Natl Acad Sci U S A. 2022 Oct 18;119(42):e2205772119. doi: 10.1073/pnas.2205772119. Epub 2022 Oct 10.

ABSTRACT

The power grid is going through significant changes with the introduction of renewable energy sources and the incorporation of smart grid technologies. These rapid advancements necessitate new models and analyses to keep up with the various emergent phenomena they induce. A major prerequisite of such work is the acquisition of well-constructed and accurate network datasets for the power grid infrastructure. In this paper, we propose a robust, scalable framework to synthesize power distribution networks that resemble their physical counterparts for a given region. We use openly available information about interdependent road and building infrastructures to construct the networks. In contrast to prior work based on network statistics, we incorporate engineering and economic constraints to create the networks. Additionally, we provide a framework to create ensembles of power distribution networks to generate multiple possible instances of the network for a given region. The comprehensive dataset consists of nodes with attributes, such as geocoordinates; type of node (residence, transformer, or substation); and edges with attributes, such as geometry, type of line (feeder lines, primary or secondary), and line parameters. For validation, we provide detailed comparisons of the generated networks with actual distribution networks. The generated datasets represent realistic test systems (as compared with standard test cases published by Institute of Electrical and Electronics Engineers (IEEE)) that can be used by network scientists to analyze complex events in power grids and to perform detailed sensitivity and statistical analyses over ensembles of networks.

PMID:36215503 | DOI:10.1073/pnas.2205772119

Proc Natl Acad Sci U S A. 2022 Oct 18;119(42):e2204405119. doi: 10.1073/pnas.2204405119. Epub 2022 Oct 10.

ABSTRACT

Ecosystems are complex systems of various physical, biological, and chemical processes. Since ecosystem dynamics are composed of a mixture of different levels of stochasticity and nonlinearity, handling these data is a challenge for existing methods of time series-based causal inferences. Here, we show that, by harnessing contemporary machine learning approaches, the concept of Granger causality can be effectively extended to the analysis of complex ecosystem time series and bridge the gap between dynamical and statistical approaches. The central idea is to use an ensemble of fast and highly predictive artificial neural networks to select a minimal set of variables that maximizes the prediction of a given variable. It enables decomposition of the relationship among variables through quantifying the contribution of an individual variable to the overall predictive performance. We show how our approach, EcohNet, can improve interaction network inference for a mesocosm experiment and simulated ecosystems. The application of the method to a long-term lake monitoring dataset yielded interpretable results on the drivers causing cyanobacteria blooms, which is a serious threat to ecological integrity and ecosystem services. Since performance of EcohNet is enhanced by its predictive capabilities, it also provides an optimized forecasting of overall components in ecosystems. EcohNet could be used to analyze complex and hybrid multivariate time series in many scientific areas not limited to ecosystems.

PMID:36215500 | DOI:10.1073/pnas.2204405119