Researchers must make numerous choices when conducting factor analyses, each of which can have significant ramifications on the model results. They must decide on an appropriate sample size to ...achieve accurate parameter estimates and adequate power, a factor model and estimation method, a method for determining the number of factors and evaluating model fit, and a rotation criterion. Unfortunately, researchers continue to use outdated methods in each of these areas. The present article provides a current overview of these areas in an effort to provide researchers with up-to-date methods and considerations in both exploratory and confirmatory factor analysis. A demonstration was provided to illustrate current approaches. Choosing between confirmatory and exploratory methods is also discussed, as researchers often make incorrect assumptions about the application of each.
Exomoons represent an outstanding challenge in modern astronomy, with the potential to provide rich insights into planet formation theory and habitability. In this work, we stack the phase-folded ...transits of 284 viable moon hosting Kepler planetary candidates, in order to search for satellites. These planets range from Earth- to Jupiter-sized and from ∼0.1 to 1.0 au in separation-so-called "warm" planets. Our data processing includes two-pass harmonic detrending, transit timing variations, model selection, and careful data quality vetting to produce a grand light curve with an rms of 5.1 ppm. We find that the occurrence rate of Galilean analog moon systems for planets orbiting between ∼0.1 and 1.0 au can be constrained to be to 95% confidence for the 284 KOIs considered, with a 68.3% confidence interval of . A single-moon model of variable size and separation locates a slight preference for a population of short-period moons with radii ∼0.5 R⊕ orbiting at 5-10 planetary radii. However, we stress that the low Bayes factor of just 2 in this region means it should be treated as no more than a hint at this time. Splitting our data into various physically motivated subsets reveals no strong signal. The dearth of Galilean analogs around warm planets places the first strong constraint on exomoon formation models to date. Finally, we report evidence for an exomoon candidate Kepler-1625b I, which we briefly describe ahead of scheduled observations of the target with the Hubble Space Telescope.
Importance The rapid proliferation of COVID-19 has left governments scrambling, and several data aggregators are now assisting in the reporting of county cases and deaths. The different variables ...affecting reporting (e.g., time delays in reporting) necessitates a well-documented reliability study examining the data methods and discussion of possible causes of differences between aggregators. Objective To statistically evaluate the reliability of COVID-19 data across aggregators using case fatality rate (CFR) estimates and reliability statistics. Design, setting, and participants Cases and deaths were collected daily by volunteers via state and local health departments, as primary sources and newspaper reports, as secondary sources. In an effort to begin comparison for reliability statistical analysis, BroadStreet collected data from other COVID-19 aggregator sources, including USAFacts, Johns Hopkins University, New York Times, The COVID Tracking Project. Main outcomes and measures COVID-19 cases and death counts at the county and state levels. Results Lower levels of inter-rater agreement were observed across aggregators associated with the number of deaths, which manifested itself in state level Bayesian estimates of COVID-19 fatality rates. Conclusions and relevance A national, publicly available data set is needed for current and future disease outbreaks and improved reliability in reporting.
Finding a balance between the preservation of habitat, species and the sustainable development of human activities in Marine Protected Areas (MPAs) is made even more challenging in coastal areas ...where sediment dynamics entails naturally changing habitats. To achieve this goal, a solid knowledge base is needed, and reviews are essential. Starting from an extensive review of sediment dynamics and coastal evolution at three-time scales (from millenaries to events), in the Gironde and Pertuis Marine Park (GPMP, French Atlantic coast), we investigated the interactions between human activities, sediment dynamics and morphological evolution in the GPMP. Five activities were identified as having a maximum interaction with coastal dynamics: Land reclamation, shellfish farming, coastal defences, dredging and sand mining. In sheltered areas, where natural sediment fill occurs, land reclamation and shellfish farming increase sedimentation through a positive feedback mechanism, leading to instability. Natural coastal erosion and sediment fill in harbours and tidal channels are fought by coastal defences and dredging, respectively, creating negative feedback and stability. However, these activities also generate negative side effects such as upper beach erosion, pollution, and increased turbidity. Sand mining, mainly developed in submarine incised valleys, results in a deepening of the sea floor, which is naturally filled by sediments from surrounding areas, tending towards shoreface profile restoration. However, sand extraction exceeds natural renewal rates, and may impact the stability of coastal ecosystems in the long term. These activities are at the heart of environmental management and preservation issues. This review and a discussion of the interactions between human activities and coastal behaviour enabled us to make recommendations that could counteract instabilities and negative side effects. They mainly include depolderization, strategic retreat, optimization and sufficiency. Given the diversity of the coastal environments and human activities found in the GPMP, this work is transferable to many MPAs and coastal areas whose objective is to foster sustainable human activities compatible with habitat preservation.
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•Complex interactions occur between sedimentary coastal ecosystems and human activities.•Deep knowledge of sediment dynamic is needed to manage human activities and sedimentary coastal ecosystems preservation.•Our main recommendation is to reduce instabilities (positive feed-back) and negative side effects.•Ecosystem-based solutions are strongly recommended.
•A total of 3,274 participants was included in this study. 23.67% of the participants met the criteria for a depressive episode.•Higher age, spirituality, social support, resiliency, and quality of ...life were associated with less depressive symptoms during COVID-19 quarantine in Brazil.•Quarantine length; mental health treatment; chronic disease; age; sex; lower levels of spirituality, social support, resilience, quality of life, physical exercise, and education; and unpaid occupation were found to be predictors of depressive symptoms during COVID-19 quarantine in Brazil.
In early 2020, Sars-Cov-2 was identified in China as a new coronavirus. Due to its transmission, Sars-Cov-2 has spread rapidly across the world. In the early stage of the disease outbreak, psychiatric symptoms have been reported, including depressive symptoms. In this study, we assessed the prevalence of depressive symptoms in quarantine and its association with sociodemographic variables and known protective factors for depression, such as spirituality, social support, resilience, and quality of life.
A cross-sectional web-based questionnaire was distributed via social media. The instruments consisted of the 8-item EUROHIS-QOL, PHQ-9, Social Support Questionnaire, WHOQoL-SRPB, and CD-RISC.
A total of 3,274 participants were included in this study. 23.67% of the participants met the criteria for a depressive episode. Higher age, spirituality, social support, resiliency, and quality of life were associated with less depressive symptoms. Quarantine length; mental health treatment; chronic disease; age; sex; lower levels of spirituality, social support, resilience, quality of life, physical exercise, and education; and unpaid occupation were found to be predictors of depressive symptoms during COVID-19 quarantine.
The data are limited to the pandemic initial period, the sample isn't random and the use of self-reported questionnaires are some limitations of our study. Conclusions: During the initial phase of the COVID-19 outbreak in Brazil, quarantine time, treatment for mental health, chronic illness, lower levels of education, and unpaid occupation were positively associated with depressive symptoms. Age, sex, spirituality, social support, resilience, quality of life, and physical exercise showed a negative relationship with depressive symptoms.
Oxidative stress is an established dementia pathway, but it is unknown if the use of antioxidant supplements can prevent dementia.
To determine if antioxidant supplements (vitamin E or selenium) used ...alone or in combination can prevent dementia in asymptomatic older men.
The Prevention of Alzheimer's Disease by Vitamin E and Selenium (PREADViSE) trial began as a double-blind randomized clinical trial in May 2002, which transformed into a cohort study from September 2009 to May 2015. The PREADViSE trial was ancillary to the Selenium and Vitamin E Cancer Prevention Trial (SELECT), a randomized clinical trial of the same antioxidant supplements for preventing prostate cancer, which closed in 2009 owing to findings from a futility analysis. The PREADViSE trial recruited 7540 men, of whom 3786 continued into the cohort study. Participants were at least 60 years old at study entry and were enrolled at 130 SELECT sites, and Cox proportional hazards models were used in a modified intent-to-treat analysis to compare hazard rates among the study arms.
Participants were randomized to vitamin E, selenium, vitamin E and selenium, or placebo. While taking study supplements, enrolled men visited their SELECT site and were evaluated for dementia using a 2-stage screen. During the cohort study, men were contacted by telephone and assessed using an enhanced 2-stage cognitive screen. In both phases, men were encouraged to visit their physician if the screen results indicated possible cognitive impairment.
Dementia case ascertainment relied on a consensus review of the cognitive screens and medical records for men with suspected dementia who visited their physician for an evaluation or by review of all available information, including a functional assessment screen.
The mean (SD) baseline age of the 7540 participants was 67.5 (5.3) years, with 3936 (52.2%) reporting a college education or better, 754 (10.0%) reporting black race, and 505 (6.7%) reporting Hispanic ethnicity. Dementia incidence (325 of 7338 men 4.4%) was not different among the 4 study arms. A Cox model, which adjusted incidence for participant demographic information and baseline self-reported comorbidities, yielded hazard ratios of 0.88 (95% CI, 0.64-1.20) for vitamin E, 0.83 (0.60-1.13) for selenium, and 1.00 (0.75-1.35) for the combination compared with placebo.
Neither supplement prevented dementia. To our knowledge, this is the first study to investigate the long-term association of antioxidant supplement use and dementia incidence among asymptomatic men.
This text addresses the strongly coupled issues of the nature of the ground state and properties of dense (quark) matter, as well as the matter composition of a compact star. The calculations are ...physically motivated, helping the reader to 'learn by doing'.
Mount Elbrus, Europe's tallest and largely glaciated volcano, is made of silicic lavas and is known for Holocene eruptions, but the size and state of its magma chamber remain poorly constrained. We ...report high spatial resolution U-Th-Pb zircon ages, co-registered with oxygen and hafnium isotopic values, span ~ 0.6 Ma in each lava, documenting magmatic initiation that forms the current edifice. The best-fit thermochemical modeling constrains magmatic fluxes at 1.2 km
/1000 year by hot (900 °C), initially zircon-undersaturated dacite into a vertically extensive magma body since ~ 0.6 Ma, whereas a volcanic episode with eruptible magma only extends over the past 0.2 Ma, matching the age of oldest lavas. Simulations explain the total magma volume of ~ 180 km
, temporally oscillating δ
O and εHf values, and a wide range of zircon age distributions in each sample. These data provide insights into the current state (~ 200 km
of melt in a vertically extensive system) and the potential for future activity of Elbrus calling for much-needed seismic imaging. Similar zircon records worldwide require continuous intrusive activity by magmatic accretion of silicic magmas generated at depths, and that zircon ages do not reflect eruption ages but predate them by ~ 10
to 10
years reflecting protracted dissolution-crystallization histories.
The aim of this study was to determine whether virtual surgical planning (VSP) is an accurate method for positioning the maxilla when compared to conventional articulator model surgery (CMS), through ...the superimposition of computed tomography (CT) images. This retrospective study included the records of 30 adult patients submitted to bimaxillary orthognathic surgery. Two groups were created according to the treatment planning performed: CMS and VSP. The treatment planning protocol was the same for all patients. Pre- and postoperative CT images were superimposed and the linear distances between upper jaw reference points were measured. Measurements were then compared to the treatment planning, and the difference in accuracy between CMS and VSP was determined using the t-test for independent samples. The success criterion adopted was a mean linear difference of <2mm. The mean linear difference between planned and obtained movements for CMS was 1.27±1.05mm, and for VSP was 1.20±1.08mm. With CMS, 80% of overlapping reference points had a difference of <2mm, while for VSP this value was 83.6%. There was no statistically significant difference between the two techniques regarding accuracy (P>0.05).
Despite the broad literature base on factor analysis best practices, research seeking to evaluate a measure's psychometric properties frequently fails to consider or follow these recommendations. ...This leads to incorrect factor structures, numerous and often overly complex competing factor models and, perhaps most harmful, biased model results. Our goal is to demonstrate a practical and actionable process for factor analysis through (a) an overview of six statistical and psychometric issues and approaches to be aware of, investigate, and report when engaging in factor structure validation, along with a flowchart for recommended procedures to understand latent factor structures; (b) demonstrating these issues to provide a summary of the updated Posttraumatic Stress Disorder Checklist (PCL-5) factor models and a rationale for validation; and (c) conducting a comprehensive statistical and psychometric validation of the PCL-5 factor structure to demonstrate all the issues we described earlier. Considering previous research, the PCL-5 was evaluated using a sample of 1,403 U.S. Air Force remotely piloted aircraft operators with high levels of battlefield exposure. Previously proposed PCL-5 factor structures were not supported by the data, but instead a bifactor model is arguably more statistically appropriate.
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