Category: Statistics

J Opt Soc Am A Opt Image Sci Vis. 2021 Jul 1;38(7):908-923. doi: 10.1364/JOSAA.413772.

ABSTRACT

It is well known that natural images possess statistical regularities that can be captured by bandpass decomposition and divisive normalization processes that approximate early neural processing in the human visual system. We expand on these studies and present new findings on the properties of space-time natural statistics that are inherent in motion pictures. Our model relies on the concept of temporal bandpass (e.g., lag) filtering in lateral geniculate nucleus (LGN) and area V1, which is similar to smoothed frame differencing of video frames. Specifically, we model the statistics of the differences between adjacent or neighboring video frames that have been slightly spatially displaced relative to one another. We find that when these space-time differences are further subjected to locally pooled divisive normalization, statistical regularities (or lack thereof) arise that depend on the local motion trajectory. We find that bandpass and divisively normalized frame differences that are displaced along the motion direction exhibit stronger statistical regularities than for other displacements. Conversely, the direction-dependent regularities of displaced frame differences can be used to estimate the image motion (optical flow) by finding the space-time displacement paths that best preserve statistical regularity.

PMID:34263746 | DOI:10.1364/JOSAA.413772

Appl Opt. 2021 Jul 1;60(19):5517-5522. doi: 10.1364/AO.424362.

ABSTRACT

In inertial confinement fusion (ICF) systems, a continuous phase plate is often used to generate a speckle pattern in order to reduce the growth of parametric instabilities. An analytic model based on the vector diffraction theory is proposed in order to analyze the characteristics of the speckle field generated under sharper focusing conditions. The statistical and spatial autocorrelation function of the speckle field are deduced and calculated. Results show that more accurate results can be achieved by vector theory than by scalar theory. Furthermore, since light-field components in different directions are involved in the vector diffraction integral, more comprehensive information on statistical characteristics of the speckle field can be discovered. Additionally, the impact of the speckle field on three waves plasma parametric instabilities are discussed. Results show that speckle field generated under sharp focusing conditions can efficiently increase the phase mismatch among the three waves and then limit the growth of the instability.

PMID:34263839 | DOI:10.1364/AO.424362

J Orthod. 2021 Jul 15:14653125211028862. doi: 10.1177/14653125211028862. Online ahead of print.

ABSTRACT

OBJECTIVE: To determine the degree to which the anteroposterior (AP) skeletal jaw relation can accurately be determined from a silhouetted clinical profile photograph and whether the level of agreement is influenced by patient vertical proportions.

DESIGN: Cross-sectional study.

SETTING: University Dental Hospital of Manchester, United Kingdom.

PARTICIPANTS: Specialist orthodontists.

METHOD: Eight specialist orthodontists assessed 37 silhouetted profile photographs of individuals aged 11-19 years and determined the class and severity of AP skeletal pattern. These assessments were compared to corresponding lateral cephalometric radiographs, where ANB values, supplemented by an Eastman Correction and a Wits Appraisal, where appropriate, were used for sagittal skeletal classification.

RESULTS: The agreement between silhouette and cephalometric AP determination yielded a weighted kappa score of 0.207 (95% confidence interval [CI] 0.135-0.278), which indicates only a fair level of agreement. The silhouetted sagittal skeletal pattern classification, along with severity, agreed with the lateral cephalometric radiograph in 29% of instances. Class III individuals were identified correctly 19.2% of the time. There was a statistically significant difference in kappa scores between the high angle (K= 0.439; 95% CI 0.310-0.568) and low angle (K = 0.068; 95% CI 0.007-0.130) patients (P < 0.001), as well as the high and average angle (K= 0.151; 95% CI 0.031-0.270) patients (P < 0.05).

CONCLUSION: AP skeletal pattern, as determined from a lateral cephalometric radiograph, has only a fair level of agreement to that from a silhouetted profile photograph. Vertical proportions were shown to have a significant effect on the determination of the sagittal skeletal pattern and class III skeletal patterns were shown to be the most difficult to identify from profile silhouettes.

PMID:34263691 | DOI:10.1177/14653125211028862

Subst Use Misuse. 2021 Jul 15:1-4. doi: 10.1080/10826084.2021.1949615. Online ahead of print.

ABSTRACT

BACKGROUND: The effects of cannabis use in vulnerable persons with schizophrenia or schizoaffective disorder, continues to be elucidated.

METHODS: We compared 55 cannabis-only users (Group 1) with 462 non-substance users (Group 2) on measures of length of stay and number of psychiatric hospitalizations with a primary discharge diagnosis of schizophrenia or schizoaffective disorder using the Wilcoxon-Mann-Whitney non-parametric test for non-normal distributions, analysis of variance (ANOVA), and Poisson regression analysis.

RESULTS: Group 1 had a mean length of stay of 6.15 days (sd = 5.32 days) and Group 2 had a mean length of stay of 8.66 days (sd = 11.14 days) (i.e. Wilcoxon-Mann-Whitney, p = .0347; log-transformed ANOVA, p = .0203). This difference was no longer statistically significant when controlling for three covariates (p = .1543). Poisson regressions for the mean number of admissions (1.84) were not statistically significant.

CONCLUSIONS: Cannabis use may not be a good predictor of length of stay, once covariates are considered, and mean number of hospitalizations in hospitalized patients with schizophrenia or schizoaffective disorder.

PMID:34263706 | DOI:10.1080/10826084.2021.1949615

Ann Palliat Med. 2021 Jun 21:apm-21-194. doi: 10.21037/apm-21-194. Online ahead of print.

ABSTRACT

BACKGROUND: Mindfulness-based stress reduction (MBSR) intervention has been extensively applied in cancer patients for relieving symptom burden and its effectiveness has also been demonstrated. However, the effectiveness of MBSR on psychological and physical functions in lung cancer patients has not yet been determined. The aim of the present systematic review and meta-analysis seeks to determine the role of MBSR in lung cancer patients.

METHODS: A systematic search of PubMed, EMBASE, Cochrane Library, and China National Knowledgement Infrastructure (CNKI) will be carried out from their inception until to December 30, 2020. Studies investigating the comparative effects between MBSR and control groups on psychological and physical outcomes will be documented. Data concerning studies, patient characteristics, and outcomes will be extracted. Methodological quality of each eligible randomized controlled trial (RCT) will be assessed individually by two investigators independently using criteria recommended in the Cochrane Handbook for Systematic Reviews of Interventions 5.1.0. Meanwhile, Newcastle-Ottawa Quality Assessment Scale (NOS) will be used to assess methodological quality of non-randomized studies. All statistical analyses will be performed with RevMan and STATA softwares.

DISCUSSION: The role of MBSR in lung cancer patients has not yet been demonstrated. This systematic review and meta-analysis will further determine the effectiveness of MBSR on psychological and physical outcomes and QoL among lung cancer patients, which will provide golden references for developing psychological interventions in order to improve patient care and designing future studies to bridge the gap between research findings and clinical practice.

TRIAL REGISTRATION: We registered the protocol of this systematic review and meta-analysis in Open Science Framework (OSF) platform with a registration DOI of 10.17605/OSF.IO/MWVBQ (available from: https:// osf.io/mwvbq).

PMID:34263645 | DOI:10.21037/apm-21-194

Psychol Health Med. 2021 Jul 15:1-8. doi: 10.1080/13548506.2021.1954669. Online ahead of print.

ABSTRACT

To investigate the sleep quality and mental health status of healthcare professionals during the outbreak of coronavirus disease 2019 (COVID-19) in order to promote timely intervention and treatment. An Questionnaire Star of WeChat online survey was conducted at Hwamei Hospital, University of Chinese Academy of Sciences, NingBo, China. The questionnaire consisted of two parts including sociodemographic characteristics, and the Pittsburgh Sleep Quality Index (PSQI), the Generalized Anxiety Disorder (GAD-7) scale, a depression screening scale (Patient Health Questionnaire-9 [PHQ-9]) so as to investigate the sleep quality and mental health status of healthcare professionals during the outbreak of COVID-19.The data were analyzed with the t-test, χ² test, one-way analysis of variance (ANOVA) and Pearson correlation, P < 0.05 was considered statistically significant. The mean score of PSQI is 5.8 ± 3.7 and the incidence of sleep disorders was 28.8% among the healthcare professionals and was related to occupation, title, education level, role and some underlying diseases. The positive rates for anxiety and depression among the healthcare professionals were 33.2% and 39.4% according to the GAD-7 and PHQ-9. Mental health status was related to occupation, education level, role and some underlying diseases. During the COVID-19 outbreak, sleep quality was significantly correlated with anxiety and depression among the healthcare professionals. The incidences of sleep disorder, anxiety and depression among healthcare professionals have been high. Furthermore, these disorders are interrelated and require timely intervention and treatment.

PMID:34263682 | DOI:10.1080/13548506.2021.1954669

Clin Linguist Phon. 2021 Jul 15:1-19. doi: 10.1080/02699206.2021.1941263. Online ahead of print.

ABSTRACT

The purpose of the current research was to compare the lexical-grammatical skills of two-year-old children with and without repaired cleft palate (CP), accounting for the effect of variables such as vocabulary size at 18 months of age, maternal education level, and gender. Participants included 52 children with CP and 25 typically developing (TD) children. The CDI-WS was employed to measure vocabulary and grammatical skills. Significant differences were observed between the CP and TD groups with respect to the number of words, word forms (irregular nouns and verbs), word endings (overuse of plural (-s) and past tense (-ed) markers), the mean number of morphemes in their three longest utterances (M3L), and sentence complexity. In addition, compared to TD children, significantly smaller proportions of children with CP were observed to use words to talk about past and future events or use words to talk about an absent object. The difference between the CP and TD groups in terms of the size of vocabulary at 24 months of age remained statistically significant in the multivariable model. Among all predictors, the size of vocabulary at 18 months of age was identified as the most robust precursor of lexical and grammatical skills at 24 months of age. Gender was identified as a predictor of the M3L measure as an index for syntactic ability.

PMID:34263689 | DOI:10.1080/02699206.2021.1941263

Ann Palliat Med. 2021 Jul 6:apm-21-959. doi: 10.21037/apm-21-959. Online ahead of print.

ABSTRACT

BACKGROUND: One-stop hybrid coronary revascularization (HCR) combines coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) procedures simultaneously. Acute kidney injury (AKI) is a common complication after CABG or PCI. This study explored the risk factors for developing AKI after one-stop HCR.

METHODS: A total of 123 consecutive patients who underwent one-stop HCR between April 2018 and November 2020 were included in this single-center retrospective study. Postoperative AKI was observed in 11 patients (the AKI group), and 112 patients did not develop postoperative AKI (the non-AKI group). Baseline characteristics and perioperative variables were extracted from the electronic medical records and statistically analyzed.

RESULTS: Postoperative AKI occurred in 11 (8.9%) patients. Compared to patients who did not develop AKI, patients in the AKI group were older (71.0±9.5 vs. 64.1±9.2 years, P=0.019), had higher preoperative creatinine levels (92.6±16.8 vs. 69.8±14.4 mmol/L, P<0.001), experienced a greater volume of postoperative drainage on the first day [850 mL (410, 1,500) vs. 500 mL (321, 700), P=0.045], had a higher proportion of chronic renal insufficiency (eGFR <60 mL/min/1.73 m2 ) (36.4% vs. 7.1%, P=0.012), and had more perioperative transfusions (63.6% vs. 22.3%, P=0.007). Multivariate logistics analyses revealed that advanced age [odds ratio (OR) 5.44, P=0.014] and perioperative transfusions (OR 4.62, P=0.028) were independent risk factors for developing AKI after one-stop HCR.

CONCLUSIONS: One-stop HCR did not increase the incidence of postoperative AKI in our center. Advanced age (≥75 years) and perioperative transfusions were independent risk factors for developing AKI after onestop HCR. Further studies need to be conducted to confirm the risk factors of AKI after HCR procedures.

PMID:34263638 | DOI:10.21037/apm-21-959

Ann Palliat Med. 2021 Jul 14:apm-21-712. doi: 10.21037/apm-21-712. Online ahead of print.

ABSTRACT

BACKGROUND: The aim of this review was to explore the quality assessment checklists development methods in previous researches using standardized patients (SPs), as well as to propose an evidence-based checklist development procedure for quality assessment of common conditions in primary health care (PHC) settings.

METHODS: We conducted a systematic review of studies that described checklist development method and extracted the methodology in terms of the developer, the basis and processes. Based on that, we formulated the development procedure according to the recommendations of the WHO Handbook for Guideline Development.

RESULTS: We identified a total of 13 articles, and proposed the following five key steps: (I) Forming a multidisciplinary team; (II) Selecting and evaluating relevant references; (III) Extracting medical information and forming the basic items; (IV) Clinical expert consensus on the items; and (V) Pre-testing the item pool and determining final items.

CONCLUSIONS: SP has been proven to be an effective method to assess performance in practice. There are still some deficiencies in the developing of case-specific checklists using SPs. To ensure the validity and reliability of checklists, the development processes need to be more standardized and procedural.

PMID:34263643 | DOI:10.21037/apm-21-712

Ann Palliat Med. 2021 Jul 5:apm-21-956. doi: 10.21037/apm-21-956. Online ahead of print.

ABSTRACT

BACKGROUND: Palliative radiation therapy is essential to the care of patients with advanced cancer. Unfortunately, despite their benefits, the principles of palliative radiation therapy and palliative and supportive care are underrepresented in radiation oncology residency curricula. In this study, we attempted to identify areas of emphasis for future palliative radiation therapy curricula by examining the relevant questions posted to theMednet.

METHODS: Questions tagged with both “Palliation” and “Radiation Oncology” or “General Radiation Oncology” that were posted to theMednet on or before January 7, 2020 were included in this analysis. The questions were grouped thematically, and subthemes within each broader thematic group were identified. Among the thematic groups, variations in social engagement metrics were assessed using the Kruskal-Wallis Test and non-parametric analysis of variance.

RESULTS: A total of 4,188 questions tagged with the terms “Radiation Oncology,” “General Radiation Oncology,” or “Palliation” and posed between 2012 and 2020 were identified. Of these, 161 questions satisfied our inclusion criteria. Upon examination of the identified questions, eight thematic groups and several subthemes were identified, representing areas of possible emphasis for future palliative radiation therapy curricula. Among questions in different thematic groups, however, there were no statistically significant differences in any of the examined social engagement metrics.

CONCLUSIONS: We found many common question themes and subthemes in our examination of the palliative radiation oncology questions posted to theMednet. Our findings suggest that several opportunities for education exist for radiation oncology residents in regards to palliative and supportive care and palliative radiation therapy.

PMID:34263626 | DOI:10.21037/apm-21-956