Category: Statistics

Opt Lett. 2021 Jun 15;46(12):2824-2827. doi: 10.1364/OL.413102.

ABSTRACT

The instability of optical phase chaos synchronization between semiconductor lasers under master-slave open-loop configuration is investigated. The phase difference between the master and slave lasers is obtained and analyzed in experiment by heterodyne detection and Hilbert transform, and in simulation by solving the rate equations. The results show that the phase difference only maintains in a short duration time and then jumps to another value. A statistical analysis shows that both duration time and jumping values are random, proving that the phase chaos synchronization is unstable. A theoretical analysis shows that the instability of phase synchronization is caused by the jumping of the external cavity mode in the master laser.

PMID:34129550 | DOI:10.1364/OL.413102

PLoS One. 2021 Jun 15;16(6):e0251479. doi: 10.1371/journal.pone.0251479. eCollection 2021.

ABSTRACT

BACKGROUND: Smart devices (SDs) are widely used among adolescents. Numerous studies have recommended further research on this topic to find out the prevalence of SD overuse among school students and to what extent this is associated with psychological distress. The present study aimed to investigate the pattern of SD use among secondary and high school students in the state of Kuwait, as well as the possible associations with psychological problems, weight, physical activity, and school performance.

MATERIALS AND METHODS: The correlational study design aimed to survey students from public schools by using a questionnaire and valid instruments, which included: Smartphone Addiction Scale-Short Version (SAS-SV) and Stress, Anxiety, and Depression Scale-(DASS-21). Pearson’s correlation coefficient, t-tests, one-way ANOVA were applied to find associations or significant differences between the categorical variables, in which p < 0.05 was considered statistically significant.

RESULTS: The study included 1,993 students from secondary schools (48.9%) and high schools (51.1%), of which 47.5% were male and 52.5% were female. There were significant statistical differences in the pattern of use of SDs, addiction to SD use, stress, anxiety, and depression according to gender, school type, school performance, and sport engagement. In addition, there were positive correlations between students’ addiction to SD use and stress, anxiety, and depression.

CONCLUSIONS: The findings suggest that excessive SD use is associated with addiction among secondary and high school students. In addition, levels of stress, anxiety, and depression differ according to the number of hours of SD use. Strategies should be developed at the community and school levels to avoid the overuse of SDs among school-aged students.

PMID:34129598 | DOI:10.1371/journal.pone.0251479

IEEE Trans Image Process. 2021 Jun 15;PP. doi: 10.1109/TIP.2021.3087943. Online ahead of print.

ABSTRACT

In the low-photon imaging regime, noise in the image sensors is dominated by shot noise, best modeled statistically as Poisson distribution. In this work, we show that the Poisson likelihood function is very well matched with the Bayesian estimation of the “difference of log of contrast of pixel intensities.” More specifically, our work is rooted in statistical compositional data analysis, whereby we reinterpret the Aitchison geometry as a multi-resolution analysis in the log-pixel domain.We demonstrate that the difference-log-contrast has wavelet-like properties that correspond well with the human visual system, while being robust to illumination variations. We derive a denoising technique based on an approximate conjugate prior for the latent Aitchison variable that gives rise to an explicit minimum mean squared error estimation. The resulting denoising technique preserves image contrast details that are arguably more meaningful to human vision than the pixel intensity values themselves.

PMID:34129497 | DOI:10.1109/TIP.2021.3087943

J Hypertens. 2021 Jun 14. doi: 10.1097/HJH.0000000000002911. Online ahead of print.

ABSTRACT

AIM: Evidence on systolic dysfunction, as assessed by left ventricular (LV) mechanics, in hypertensive heart disease phenotyped by abnormal LV geometric patterns is still limited. Thus, we performed a systematic meta-analysis of 2D/3D speckle-tracking studies in order to provide an updated comprehensive information on this topic.

METHODS: The PubMed, OVID-MEDLINE, and Cochrane library databases were analyzed to search for articles published from the inception up to 31 January 2021. Studies were identified by using MeSH terms and crossing the following search items: ‘myocardial strain’, ‘left ventricular mechanics’, ‘speckle tracking echocardiography’, ‘systolic dysfunction’, ‘hypertensive heart disease’, ‘left ventricular hypertrophy’, left ventricular remodeling”, ‘concentric hypertrophy’, ‘eccentric hypertrophy’.

RESULTS: Overall, data of 267 normotensive controls and 712 hypertensive patients (234 normal geometry, 97 LV concentric remodeling, 176 eccentric LVH, and 205 concentric LVH) from eight studies were considered. Pooled ejection fraction was similar in normotensives and in the whole group of hypertensive patients: (SMD 0.037 ± 0.05, confidence interval (CI): 0.14/0.07, P = 0.51) as well as in hypertensive subgroups. LVMI, and E/e’ gradually increased from hypertensive patients with normal geometry and concentric remodeling, to patients with eccentric and concentric LVH. LV global longitudinal strain (GLS) was lower in all hypertensive groups compared with normotensive controls, in particular, in the eccentric (SMD 1.14 ± 0.22, CI: 0.69/1.59, P < 0.0001) and concentric LVH group (SMD 1.37 ± 0.21, CI: 0.95/1.79, P < 0.0001). The meta-analysis restricted to hypertensive patients showed that GLS gradually deteriorated from hypertensive patients with normal LV geometry, across those with concentric remodeling, to participants with eccentric and concentric LVH (-19.5 ± 0.6 versus -18.8 ± 0.73 versus -17.6 ± 0.66 versus -16.5 ± 0.6%, P < 0.001 for trend). Statistical significance was reached when GLS of the concentric and eccentric LVH group but not the concentric remodeling was compared with the normal geometry one.

CONCLUSION: The present meta-analysis confirms that GLS performs better than ejection fraction in identifying systolic dysfunction in the hypertension setting. More importantly, it suggests that this occurs in patients with altered LV structure and geometry, such as LVH.

PMID:34128494 | DOI:10.1097/HJH.0000000000002911

Radiat Prot Dosimetry. 2021 Jun 15:ncab088. doi: 10.1093/rpd/ncab088. Online ahead of print.

ABSTRACT

X-ray usage in medical diagnosis could have hurtful effects for both patient and medical imaging wards’ personnel as a result of failure to follow radiation protection (RP) principles (shielding, distance and time) by radiographers. This cross-sectional descriptive-analytical study was carried out by valid and reliable online questionnaire, which was completed by 103 radiographers. Data were analyzed by using descriptive statistics (mean, standard deviation and frequency) and analytical statistics (Pearson’s correlation coefficient test, Student’s independent t-test and analysis of variance test) in the Statistical Package for Social Sciences version 20 (sig: P < 0.05). The study’s response rate was 67.32%. The mean scores of participants’ total, RP and device knowledge were 42.76, 42.86 and 42.72 out of 100, respectively. Work experience and age of participants were significantly related to device and total knowledge (P < 0.01). Results revealed an undesirable level of participants’ awareness, indicating the necessity of holding training courses, especially for less experienced radiographers.

PMID:34128525 | DOI:10.1093/rpd/ncab088

J Forensic Sci. 2021 Jun 15. doi: 10.1111/1556-4029.14776. Online ahead of print.

ABSTRACT

The purpose of the present study is to investigate dynamics underlying drug abuse and identify statistical correlations/patterns of forensic findings and sociodemographic factors in a population of illicit substance users. The following long-term studies were conducted: (a) a retrospective autopsy cohort study on autopsy incidents with available toxicological screening results (N = 482) in investigation of any possible forensic associations of exposure to illicit drugs; and (b) a cross-sectional study on a sample of arrested drug law offenders with available toxicological screening results (N = 195) as well as cluster analysis in order to possibly identify user profiles. Although outside the scope of the present study, ethanol was generally considered to be the main substance of abuse, as more than half of the premature deaths reported tested positive on the ethanol toxicology screen. Cannabis and opioid use was associated with unintentional causes of death, while an association of deliberate self-harm was noted with opioid and benzodiazepine use. Both cannabis and opioid use correlated with significantly younger ages (more than a decade) of premature death. Most frequently, an onset of substance use was reported in the early 20s with cannabis use. Although 65.3% of the subjects were diagnosed as dependent and unable to eliminate substance use on their own, only 7.7% of the subjects in the users’ population had ever accessed appropriate support through rehabilitation programs.

PMID:34128547 | DOI:10.1111/1556-4029.14776

J Sports Sci. 2021 Jun 15:1-7. doi: 10.1080/02640414.2021.1935672. Online ahead of print.

ABSTRACT

The aim of the present study was to evaluate the impact of Ramadan fasting on sleep quality and daytime sleepiness in team sport referees. Seventy-eight male amateur team sport referees (age: 31.1 ± 10.8 years) participated in this study. Participants responded to the Arabic version of the Pittsburgh Sleep Quality Index (PSQI) and the Epworth sleepiness scale (ESS) questionnaires before (10-days prior) and during (last 7-days) the month of Ramadan.PSQI and ESS scores increased significantly during Ramadan (both p < .001, ES = 0.56 and 0.54, respectively) with 83.3% of participants scoring ≥5 in the PSQI. The percentage of participants suffering from severe excessive daytime sleepiness (ESS score ≥ 16) was 3.8% before vs. 7.7% during Ramadan (p < 0.001). Sleep duration decreased by ~ 1 h during Ramadan (p < .001, ES = 0.61) and was associated with a delay in bedtime of ~ 2 h (p < 0.001, ES = 0.7) and of wake-up time of ~ 1 h (p < 0.001, ES = 0.5). The score for daytime dysfunction and subjective sleep perception, as components of the PSQI, increased (both p < 0.001; ES = 0.79, ES = 0.57, respectively), whereas the score for the use of sleep medication decreased during vs. before Ramadan (p = 0.041, ES = 0.47). Ramadan fasting impaired sleep quality and increased daytime sleepiness in team sport referees. Future studies, using objective assessment tools, are warranted.

PMID:34128455 | DOI:10.1080/02640414.2021.1935672

Elife. 2021 Jun 15;10:e66398. doi: 10.7554/eLife.66398.

ABSTRACT

We previously reported xanthohumol (XN), and its synthetic derivative tetrahydro-XN (TXN), attenuates high-fat diet (HFD)-induced obesity and metabolic syndrome in C57Bl/6J mice. The objective of the current study was to determine the effect of XN and TXN on lipid accumulation in the liver. Non-supplemented mice were unable to adapt their caloric intake to 60% HFD, resulting in obesity and hepatic steatosis; however, TXN reduced weight gain and decreased hepatic steatosis. Liver transcriptomics indicated that TXN might antagonize lipogenic PPARγ actions in vivo. XN and TXN inhibited rosiglitazone-induced 3T3-L1 cell differentiation concomitant with decreased expression of lipogenesis-related genes. A peroxisome proliferator activated receptor gamma (PPARγ) competitive binding assay showed that XN and TXN bind to PPARγ with an IC₅₀ similar to pioglitazone and 8-10 times stronger than oleate. Molecular docking simulations demonstrated that XN and TXN bind in the PPARγ ligand-binding domain pocket. Our findings are consistent with XN and TXN acting as antagonists of PPARγ.

PMID:34128467 | DOI:10.7554/eLife.66398

Blood Press Monit. 2021 Jun 10. doi: 10.1097/MBP.0000000000000553. Online ahead of print.

ABSTRACT

OBJECTIVE: To propose and validate a new method for estimating cardiac output based on the total arterial compliance (Ct) formula that does not need an arterial waveform and to apply it to brachial oscillometric blood pressure measurements (OBPMs).

METHODS: One hundred subjects with normal heart anatomy and function were included. Reference values for cardiac output were measured with echocardiography, and Ct was calculated with a two-element Windkessel model. Then, a statistical model of arterial compliance (Ce) was used to estimate cardiac output. Finally, the measured and estimated cardiac output values were compared for accuracy and reproducibility.

RESULTS: The model was derived from the data of 70 subjects and prospectively tested with the data from the remaining 30 individuals. The mean age of the whole group was 43.4 ± 12.8 years, with 46% women. The average blood pressure (BP) was 107.1/65.0 ± 15.0/9.6 mmHg and the average heart rate was 67.7 ± 11.4 beats/min. The average Ct was 1.39 ± 0.27 mL/mmHg and the average cardiac output was 5.5 ± 1.0 L/min. The mean difference in the cardiac output estimated by the proposed methodology vs. that measured by Doppler echocardiography was 0.022 L/min with an SD of 0.626 L/min. The intraclass correlation coefficient was 0.93, and the percentage error was 19%.

CONCLUSION: Cardiac output could be reliably and noninvasively obtained with brachial OBPMs through a novel method for estimating Ct without the need for an arterial waveform. The new method could identify hemodynamic factors that explain BP values in an ambulatory care setting.

PMID:34128491 | DOI:10.1097/MBP.0000000000000553

Vet Pathol. 2021 Jun 15:3009858211022696. doi: 10.1177/03009858211022696. Online ahead of print.

ABSTRACT

Sarcoids are the most common cutaneous tumor of equids and are caused by bovine papillomavirus (BPV). Different clinical subtypes of sarcoids are well characterized clinically but not histologically, and it is not known whether viral activity influences the clinical or histological appearance of the tumors. The aim of this study was to verify whether the development of different clinical types of sarcoids or the presence of certain histological features were associated with BPV distribution within the tumor. The presence of BPV was assessed by polymerase chain reaction (PCR) and visualized in histological sections by chromogenic in situ hybridization (CISH) in 74 equine sarcoids. Furthermore, to better characterize the molecular features of neoplastic cells, immunohistochemistry for S100, smooth muscle actin-α (αSMA), and fibroblast-associated protein-α (FAPα) was performed. The presence of BPV was confirmed in all tissues examined by either or both PCR and CISH (72/74, 97% each). Of 70/74 CISH-positive cases, signal distribution appeared as either diffuse (61/70, 87%) or subepithelial (9/70, 13%); the latter was more frequently observed in the verrucous subtype. However, no statistically significant association was found between clinical subtypes and specific histological features or hybridization pattern. Moreover, CISH signal for BPV was not detected in the epidermis overlying sarcoids nor in the tissue surrounding the neoplasms. By immunohistochemistry, αSMA confirmed the myofibroblastic differentiation of neoplastic cells in 28/74 (38%) sarcoids. Using tissue microarrays, FAPα labelling was observed in neoplastic fibroblasts of all sarcoids, suggesting this marker as a potential candidate for the immunohistochemical diagnosis of sarcoids.

PMID:34128437 | DOI:10.1177/03009858211022696