Category: Statistics

Am J Respir Crit Care Med. 2021 Nov 12. doi: 10.1164/rccm.202109-2096LE. Online ahead of print.

NO ABSTRACT

PMID:34767493 | DOI:10.1164/rccm.202109-2096LE

Phys Rev Lett. 2021 Oct 29;127(18):180602. doi: 10.1103/PhysRevLett.127.180602.

ABSTRACT

The statistical character of electron beams used in current technologies, as described by a stream of particles, is random in nature. Using coincidence measurements of femtosecond pulsed electron pairs, we report the observation of sub-Poissonian electron statistics that are nonrandom due to two-electron Coulomb interactions, and that exhibit an antibunching signal of 1 part in 4. This advancement is a fundamental step toward observing a strongly quantum degenerate electron beam needed for many applications, and in particular electron correlation spectroscopy.

PMID:34767409 | DOI:10.1103/PhysRevLett.127.180602

Phys Rev Lett. 2021 Oct 29;127(18):181102. doi: 10.1103/PhysRevLett.127.181102.

ABSTRACT

It was recently pointed out that very energetic subclasses of supernovae (SNe), like hypernovae and superluminous SNe, might host ultrastrong magnetic fields in their core. Such fields may catalyze the production of feebly interacting particles, changing the predicted emission rates. Here we consider the case of axionlike particles (ALPs) and show that the predicted large scale magnetic fields in the core contribute significantly to the ALP production, via a coherent conversion of thermal photons. Using recent state-of-the-art supernova (SN) simulations, including magnetohydrodynamics, we find that, if ALPs have masses m_{a}∼O(10) MeV, their emissivity in such rare but exciting conditions via magnetic conversions would be over 2 orders of magnitude larger than previously estimated. Moreover, the radiative decay of these massive ALPs would lead to a peculiar delay in the arrival times of the daughter photons. Therefore, high-statistics gamma-ray satellites can potentially discover MeV ALPs in an unprobed region of the parameter space and shed light on the magnetohydrodynamical nature of the SN explosion.

PMID:34767416 | DOI:10.1103/PhysRevLett.127.181102

Phys Rev Lett. 2021 Oct 29;127(18):180601. doi: 10.1103/PhysRevLett.127.180601.

ABSTRACT

Optical speckle fields with both non-Rayleigh statistics and nondiffracting characteristics in propagation are an important light source for many applications. However, tailoring either non-Rayleigh statistical speckles or nondiffracting speckles are only investigated independently in previous studies. Here, we report the first observation of optical speckles that remain diffraction-free over a long axial distance while keeping non-Rayleigh statistics simultaneously. We further show the enhancement of Anderson localization of light with the non-Rayleigh nondiffracting speckles. The work presented here provides a versatile framework for customizing optical fields with desired speckle patterns for applications in the fields of solid-state physics, cold atoms, and optical imaging.

PMID:34767403 | DOI:10.1103/PhysRevLett.127.180601

Phys Rev Lett. 2021 Oct 29;127(18):181101. doi: 10.1103/PhysRevLett.127.181101.

ABSTRACT

We resolve the fate of the two original apparent horizons during the head-on merger of two nonspinning black holes. We show that, following the appearance of the outer common horizon and subsequent interpenetration of the original horizons, they continue to exist for a finite period of time before they are individually annihilated by unstable marginally outer trapped surfaces (MOTSs). The inner common horizon vanishes in a similar, though independent, way. This completes the understanding of the analog of the event horizon’s “pair of pants” diagram for the apparent horizon. Our result is facilitated by a new method for locating MOTSs based on a generalized shooting method. We also discuss the role played by the MOTS stability operator in discerning which among a multitude of MOTSs should be considered as black hole boundaries.

PMID:34767408 | DOI:10.1103/PhysRevLett.127.181101

J Pediatr Endocrinol Metab. 2021 Nov 11. doi: 10.1515/jpem-2021-0449. Online ahead of print.

ABSTRACT

OBJECTIVES: Since the beginning of the COVID-19 pandemic, there has been a consistent decrease in the number of admissions to the emergency department, leading to a delay in the diagnosis of several pathologies. The time from onset of symptoms to the diagnosis of Type 1 diabetes is highly variable. This treatment delay can lead to the appearance of ketoacidosis.

METHODS: Retrospective study of inaugural Type 1 diabetes cases, from March 2016 to March 2021. The pandemic group was considered between March 2020 to March 2021, and the remaining period was considered as pre-pandemic. Clinical variables were analysed: duration of symptoms, weight loss and value of ketonemia and glycated haemoglobin on admission. The mean differences were considered statistically significant at p<0.05.

RESULTS: 103 inaugural episodes of Type 1 diabetes were registered. The pandemic group had a lower mean age when compared to pre-pandemic group, and 51.7% of the episodes had ketoacidosis with a higher relative risk of ketoacidosis and severe ketoacidosis, when compared the pandemic with pre-pandemic group, there was a longer symptom evolution time (34 vs. 20 days), greater weight loss occurred (9.5% vs. 6.3%), the pH and HCO₃^– values were lower (7.30 vs. 7.36 and 16.43 vs. 20.71 mmol/L respectively) and ketonemia was higher (5.9 vs. 2.3 mmol/L).

CONCLUSIONS: The COVID-19 pandemic caused a delay in the diagnosis of Type 1 diabetes, greater length of disease, greater weight loss, higher ketonemia and lower pH and HCO₃^–. There was greater ketoacidosis relative risk in pandemic group when compared to pre-pandemic group.

PMID:34766743 | DOI:10.1515/jpem-2021-0449

Obes Rev. 2021 Nov 12:e13383. doi: 10.1111/obr.13383. Online ahead of print.

ABSTRACT

We conducted a systematic review and meta-analysis of the associations between prenatal exposure to persistent organic pollutants (POPs) and childhood obesity. We focused on organochlorines (dichlorodiphenyltrichloroethane [DDT], dichlorodiphenyldichloroethylene [DDE], hexachlorobenzene [HCB], and polychlorinated biphenyls [PCBs]), perfluoroalkyl and polyfluoroalkyl substances (PFAS), and polybrominated diphenyl ethers (PBDEs) that are the POPs more widely studied in environmental birth cohorts so far. We search two databases (PubMed and Embase) through July/09/2021 and identified 33 studies reporting associations with prenatal organochlorine exposure, 21 studies reporting associations with prenatal PFAS, and five studies reporting associations with prenatal PBDEs. We conducted a qualitative review. Additionally, we performed random-effects meta-analyses of POP exposures, with data estimates from at least three prospective studies, and BMI-z. Prenatal DDE and HCB levels were associated with higher BMI z-score in childhood (beta: 0.12, 95% CI: 0.03, 0.21; I² : 28.1% per study-specific log increase of DDE and beta: 0.31, 95% CI: 0.09, 0.53; I² : 31.9% per study-specific log increase of HCB). No significant associations between PCB-153, PFOA, PFOS, or pentaPBDEs with childhood BMI were found in meta-analyses. In individual studies, there was inconclusive evidence that POP levels were positively associated with other obesity indicators (e.g., waist circumference).

PMID:34766696 | DOI:10.1111/obr.13383

J Esthet Restor Dent. 2021 Nov 12. doi: 10.1111/jerd.12833. Online ahead of print.

ABSTRACT

OBJECTIVE: This study aimed to evaluate the fracture strength and failure modes of different core techniques in teeth with simulated coronal destruction.

MATERIALS AND METHODS: Forty teeth were endodontically prepared and the specimens were divided into four experimental groups (n = 10) according to the core composition: Filtek One Bulk Fill-FOBF, Filtek Z350 XT-FZ350 (standard group), Filtek Bulk Fill Flow-FBFF, and LuxaCore Z-LCZ. CAD/CAM Monolithic zirconia crowns were obtained and cemented with RelyX U200. After storage in distilled water at 37°C for 48 h, the specimens were subjected to thermal cycling and to compressive strength mechanical tests. Statistical analyses (α = 0.05) were performed by non-parametric Kruskal-Wallis, Dunn post hoc, and Fisher’s exact tests.

RESULTS: No significant differences (p > 0.05) were observed among FOBF, FZ350, and FBFF (mean ranks = 20.30, 12.20, and 23.20, respectively). LCZ (mean rank = 26.30) produced results similar to those of FOBF and FBFF (p > 0.05) and higher than those of FZ350 (p = 0.042). The most frequent type of failure was irreparable, regardless of the experimental condition. The lowest percentages of reparable fractures were produced by FOBF group (10%).

CONCLUSIONS: The use of bulk fill materials, including the “core-and-post” LCZ dual-cure resin composite, did not impair the fracture strength of endodontically treated teeth with coronal destruction.

CLINICAL SIGNIFICANCE: Resin composite bulk fill materials that can be used as a core-and-post cementation in an only stage are interesting, since they enable clinicians to work with one only material, and avoid several materials interfaces, technical sensitivity, and longer chair-time due to multistep procedures.

PMID:34766704 | DOI:10.1111/jerd.12833

J Nurs Scholarsh. 2021 Nov 12. doi: 10.1111/jnu.12730. Online ahead of print.

ABSTRACT

PURPOSE: This study aimed to investigate the predictors of self-care behavior among homebound older adults using the Health Empowerment theory as a framework.

DESIGN: This was a cross-sectional, predictive correlational study.

METHODS: Sixty-eight participants were randomly selected from five Hong Kong community centers from May 21, 2020 through July 20, 2020. Self-care behaviors were assessed using the Chinese version of Partners in Health. Self-efficacy, eHealth literacy, and perceived social support were assessed as potential predictors of self-care behaviors. A multiple linear regression analysis was adopted to examine the predictive effects.

RESULTS: The age of the sample ranged from 61 to 85 years (mean = 71.7, SD = 6.0). Participants who reported having sufficient or more than sufficient financial resources had better self-care behaviors than those who claimed to have insufficient financial resources (F = 5.08, p = 0.009). Statistically significant correlations were found between the participants’ eHealth literacy (r = 0.54, p < 0.001), perceived social support (r = 0.60, p < 0.001), and self-care behaviors. eHealth literacy (β = 0.13, p = 0.007) and perceived social support (β = 0.13, p < 0.001) were significant predictors of self-care behaviors. Collectively, the three variables accounted for 41% of the variances in self-care behaviors.

CONCLUSIONS: The findings in this study suggest that eHealth literacy and perceived social support are two key factors that predicted the self-care behaviors of this vulnerable population.

CLINICAL RELEVANCE: In this technological era, the use of eHealth, together with enhanced social support, can lead to better self-care among older adults, particularly those who are homebound.

PMID:34766694 | DOI:10.1111/jnu.12730

J Med Virol. 2021 Nov 12. doi: 10.1002/jmv.27450. Online ahead of print.

ABSTRACT

Patients with COVID-19 may recurrence positive for SARS-CoV-2 RNA after being cured and discharged from hospital. The aim of this study was to explore independent influencing factors as markers for predicting positive SARS-CoV-2 RNA recurrence. The study included 601 COVID-19 patients who were cured and discharged from the Public and Health Clinic Centre of Chengdu from January 2020 to March 2021, and the recurrence positive of patients within 6 weeks after SARS-CoV-2 RNA turned negative was followed up. We used propensity score matching to eliminate the influence of confounding factors, and multivariate Logistic regression analysis was used to determine the independent influencing factors for positive SARS-CoV-2 RNA recurrence. Multivariate Logistic regression showed that the elevated serum potassium (OR=6.537,95% CI:1.864-22.931,P=0.003), elevated blood chlorine (OR=1.169,95% CI:1.032-1.324,P=0.014) and elevated CD3⁺ CD4⁺ count (OR=1.003,95% CI:1.001-1.004,P<0.001) were identified as independent risk factors for positive SARS-CoV-2 RNA recurrence (P< 0.05).The difference in virus shedding duration (OR=1.049, 95% CI:1.000-1.100, P=0.05) was borderline statistically significant. For sensitivity analysis, we included virus shedding duration as a categorical variable in the model again, and found that the OR value related to recurrence positive increased with delayed virus shedding duration, and the trend test showed a statistical difference (P trend=0.03). Meanwhile, shortening of activated partial prothrombinase time (OR=0.908,95% CI:0.824-1.000, P=0.049) was identified as an independent protection factor for SARS-CoV-2 RNA recurrence positive.We have identified independent factors that affect the recurrence of SARS-CoV-2 RNA positive. It is recommended that doctors pay attention to these indicators when first admitted to the hospital. This article is protected by copyright. All rights reserved.

PMID:34766661 | DOI:10.1002/jmv.27450