A scaled difference test statistic \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$\tilde{T}{}_{d}$\end{document} that can be computed from standard software of structural equation models (SEM) by hand calculations was proposed in Satorra and Bentler (Psychometrika 66:507–514, 2001). The statistic \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$\tilde{T}_{d}$\end{document} is asymptotically equivalent to the scaled difference test statistic \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$\bar{T}_{d}$\end{document} introduced in Satorra (Innovations in Multivariate Statistical Analysis: A Festschrift for Heinz Neudecker, pp. 233–247, 2000), which requires more involved computations beyond standard output of SEM software. The test statistic \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$\tilde{T}_{d}$\end{document} has been widely used in practice, but in some applications it is negative due to negativity of its associated scaling correction. Using the implicit function theorem, this note develops an improved scaling correction leading to a new scaled difference statistic \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$\bar{T}_{d}$\end{document} that avoids negative chi-square values.

A family of scaling corrections aimed to improve the chi-square approximation of goodness-of-fit test statistics in small samples, large models, and nonnormal data was proposed in Satorra and Bentler (1994). For structural equations models, Satorra-Bentler's (SB) scaling corrections are available in standard computer software. Often, however, the interest is not on the overall fit of a model, but on a test of the restrictions that a null model say M0 implies on a less restricted one M1. If T0 and T1 denote the goodness-of-fit test statistics associated to M0 andM1, respectively, then typically the difference Td=T0−T1 is used as a chi-square test statistic with degrees of freedom equal to the difference on the number of independent parameters estimated under the models M0 andM1. As in the case of the goodness-of-fit test, it is of interest to scale the statistic Td in order to improve its chi-square approximation in realistic, that is, nonasymptotic and nonormal, applications. In a recent paper, Satorra (2000) shows that the difference between two SB scaled test statistics for overall model fit does not yield the correct SB scaled difference test statistic. Satorra developed an expression that permits scaling the difference test statistic, but his formula has some practical limitations, since it requires heavy computations that are not available in standard computer software. The purpose of the present paper is to provide an easy way to compute the scaled difference chi-square statistic from the scaled goodness-of-fit test statistics of models M0 and M1. A Monte Carlo study is provided to illustrate the performance of the competing statistics.

Dairy foods offer essential nutrients and bioactive compounds crucial for growth and development(1), as such they are an important component of a balanced diet. However, despite their benefits, the consumption of dairy has declined in recent years, especially among adolescents(2–4). In this regard, this study aims to evaluate the nutritional contribution of dairy intakes to the diets of adolescents in Ireland.

Analyses were based on data from the nationally representative National Teens’ Food Survey II (NTFS II; 2019-2020) in Ireland (www.iuna.net) (n = 428; 13-18yrs, 50% female). Food and beverage intake data were collected using a four-day weighed food diary. Dairy intake was classified as the intake of milk, yogurt and cheese and calcium fortified non-dairy alternatives in line with the Irish food based dietary guidelines. Whole foods that contain milk, cheese and yogurt and any relevant dairy components of composite dishes were included in the estimation of dairy intakes. Diet quality was assessed using the Diet Quality Index for Adolescents(5). Descriptive statistics and covariateadjusted univariate general linear models were used to analyse dietary intakes. Trend analysis was conducted to identify patterns in nutrient intakes and anthropometric measurements across tertiles of dairy intake.

Overall, 98% of Irish adolescents consumed dairy products and the mean daily total dairy intake was 245 ± 227 g/d, with males having higher intakes per day compared to females (319 ± 272g/d vs 171 ± 152g/d respectively). The average daily servings of dairy were 1.9 servings/d, with only 4% of teenagers achieving the recommended intake of 5 servings of dairy per day. Dairy contributed to the majority of nutrients investigated and was a high contributor to intakes of micronutrients calcium (36%), vitamin B12 (31%) and iodine (49%). Higher consumers of dairy had significantly greater mean daily intakes of protein, total sugar, saturated fat, trans fat, folate, vitamin B12, calcium, iodine, magnesium, potassium, and phosphorus compared to those in the lowest tertile of dairy intake (p <0.001). Higher consumers of dairy also had an overall higher diet quality compared to low consumers (48.0 versus 39.4%; p <0.001). No differences were noted in body weight, body mass index, percentage body fat or waist and hip circumference across tertiles of dairy consumption.

In summary, while almost all Irish adolescents consumed dairy, only 4% achieved the recommended 5 servings of dairy per day. In those consuming higher amounts of dairy, a significantly higher diet quality was observed. While this study offers valuable insights into adolescents’ intake of dairy products, its cross-sectional nature highlights the need for continued monitoring of dairy consumption patterns and nutrient intakes in this population, particularly due to the observed decline in dairy consumption noted in this age group across Europe.

Objectives: Activities that require active thinking, like occupations, may influence cognitive function and its change over time. Associations between retirement and dementia risk have been reported, however the role of retirement age in these associations is unclear. We assessed associations of occupation and retirement age with cognitive decline in the US community-based Atherosclerosis Risk in Communities (ARIC)cohort.

Methods: We included 14,090 ARIC participants, followed for changes in cognition during up to 21 years. Information on current or most recent occupation was collected at ARIC baseline (1987–1989; participants aged 45–64 years) and categorized according to the 1980 US Census protocols and the Nam-Powers-Boyd occupational status score. Follow-up data on retirement was collected during 1999–2007 and classified as retired versus not retired at age 70. Trajectories of global cognitive factor scores from ARIC visit 2 (1990–1992) to visit 5 (2011–2013) were presented, and associations with occupation and age at retirement were studied using generalized estimating equation models, stratified by race and sex, and adjusted for demographics andcomorbidities.

Results: Mean age (SD) at first cognitive assessment was 57.0 (5.72) years. Higher occupational status and white- collar occupations were significantly associated with higher cognitive function at baseline. Occupation was associated with cognitive decline over 21 years only in women, and the direction of the effect on cognitive function differed between black and white women: in white women, the decline in cognitive function was greater in homemakers and low status occupations, whereas in black women, less decline was found in homemakers and low (compared to high) occupational status. Interestingly, retirement on or before age 70 was associated with less 21-year cognitive decline in all race-sex strata, except for blackwomen.

Conclusions: Associations between occupation, retirement age and cognitive function substantially differed by race and sex. Further research should explore reasons for the observed associations and race-sex differences.

The Asian tapir Tapirus indicus is the only tapir species in Southeast Asia. It is declining across its range and is categorized as Endangered on the IUCN Red List. The forests of Sumatra are critical to Asian tapir conservation as they contain some of the last remaining populations of the species, yet conservation efforts are hindered by a lack of information on habitat suitability. We collated camera-trap data from nine landscapes across 69,500 km2 of Sumatran rainforest to help predict suitable habitat for Asian tapirs on the island. Predictions from Bayesian occupancy models demonstrated that tapir occupancy was greatest in forests below 600 m elevation and exclusively in forests with high aboveground biomass. Forests around the Barisan Mountains on the west of Sumatra provide the most suitable habitat for the species. Only 36% of the most critical habitat (i.e. 80th percentile of predicted occupancy values, or above) for tapirs is formally protected for conservation, with much of the remainder found in forests allocated to watershed protection (35%) or logging (23%). We highlight several key areas in Sumatra where tapir conservation could be bolstered, such as by leveraging existing conservation efforts for other charismatic flagships species on the island.

The prevalence of childhood obesity is increasing globally(1). While BMI is commonly used to define obesity, it is unable to differentiate between fat and muscle mass, leading to calls to measure body composition specifically(2). While several tools are available to assess body composition in infancy, it is unclear if they are directly comparable. Among a subset of healthy infants born to mothers participating in a randomised controlled trial of a preconception and antenatal nutritional supplement(3), measurements were made at ages 6 weeks (n = 58) and 6 months (n = 70) using air displacement plethysmography (ADP), whole-body dual-energy X-ray absorptiometry (DXA), and bioelectrical impedance spectroscopy (BIS). Estimates of percentage fat mass (%FM) were compared using Cohen’s kappa statistic (κ) and Bland-Altman analysis (4,5). There was none to weak agreement when comparing tertiles of %FM (κ = 0.15–0.59). When comparing absolute values, the bias (i.e., mean difference) was smallest when comparing BIS to ADP at 6 weeks (+1.7%). A similar bias was observed at 6 months when comparing DXA to ADP (+1.8%). However, when comparing BIA to DXA at both ages, biases were much larger (+7.6% and +4.7% at 6 weeks and 6 months, respectively). Furthermore, there was wide interindividual variance (limits of agreement [LOA] i.e., ± 1.96 SD) for each comparison. At 6 weeks, LOA ranged from ± 4.8 to ± 6.5% for BIA vs. DXA and BIA vs. ADP, respectively. At 6 months, LOA were even wider, ranging from ± 7.3 to ± 8.1% (DXA vs. ADP and BIA vs. DXA, respectively). Proportional biases were apparent when comparing BIS to the other tools at both ages, with BIS generally overestimating %FM more among infants with low adiposity. In addition to differences according to tool type, within-tool factors impacted body composition estimation. For ADP measurements, the choice of FFM density reference (Fomon vs. Butte) had minimal impact; however, choice of DXA software version (GE Lunar enCORE basic vs. enhanced) and BIS analysis approach (empirical equation vs. mixture theory prediction) led to very different estimates of body composition. In conclusion, when comparing body composition assessment tools in infancy, there was limited agreement between three commonly used tools. Therefore, researchers and clinicians must be cautious when conducting longitudinal analyses or when comparing findings across studies, as estimates are not comparable across tools.

OBJECTIVES/GOALS: We designed the Biocascade Exhaled Breath Sampler (BEBS) to characterize viral aerosol shedding among individuals with influenza and other respiratory virus infections. We first aimed to test the BEBS on volunteer COVID-19 cases and report the aerodynamic size distribution of exhaled breath aerosol particles carrying SARS-CoV-2 RNA. METHODS/STUDY POPULATION: From June 15 through December 15, 2022, we recruited 27 PCR-confirmed COVID-19 cases from a college campus and the surrounding community to provide 30-minute breath samples into a well-validated Gesundheit-II (G-II) exhaled breath aerosol sampler. Among these individuals, 17 provided an additional exhaled breath sample into the newly designed BEBS. We quantified samples for viral RNA using reverse transcription digital polymerase chain reaction (RT-dPCR) and determined the viral RNA copies collected within two aerosol size fractions (≤5 µm and >5 µm in diameter) from the G-II, and four aerosol size fractions (<1.15 µm, 1.15–3.2 µm, 3.3–8.2 µm, and >8.2 µm) from the BEBS. RESULTS/ANTICIPATED RESULTS: Individuals with a SARS-CoV-2 Omicron BA.4 or BA.5 infection shed virus in aerosols at an average rate of 7.5x103 RNA copies per 30-minute G-II sample, with 78% of the total RNA in aerosols ≤5 µm in diameter. Among the BEBS samples, 10% of the total viral RNA was detected in aerosols <1.15 µm, 43% in 1.15–3.2 µm, 37% in 3.3–8.2 µm, and 10% in the >8.2 µm size fraction. Based on viral RNA loads, our results indicate that exhaled aerosols ≤3.2 µm contribute the majority of SARS-CoV-2 inhalation exposure. DISCUSSION/SIGNIFICANCE: Our data provide additional evidence that respirable aerosols contribute to the spread of SARS-CoV-2. Thus, our data suggest that mitigation measures designed to reduce infectious aerosol inhalation, such as ventilation and the use of air cleaners and respirators, are needed to control the spread.

The teenage years represent a crucial period of physical and cognitive growth and development with sufficient micronutrient intakes necessary to meet high nutritional requirements. This review examines current micronutrient intakes in teenagers in the Western world in the context of public health implications including the prevalence of inadequate intakes and risk of excessive intakes. Intakes of vitamins A, D, E and C, folate, calcium, iron, magnesium, zinc and potassium in teenagers are low when compared to generally accepted recommendations, while there is little risk of excessive micronutrient intakes based on current dietary patterns. Therefore, strategies should focus on increasing micronutrient intakes in order to decrease the risk of negative impacts resulting from these low intakes. These strategies should be mindful of guidance towards an environmentally sustainable diet whilst ensuring that nutrient intakes in teenagers are not further negatively impacted. In order to identify, implement and monitor the effectiveness of such strategies, intakes of micronutrients should be continually monitored in nationally representative samples of the population for all age groups including this vulnerable cohort of teenagers.

Radiocarbon (14C) dating of sediment deposition around Antarctica is often challenging due to heterogeneity in sources and ages of organic carbon in the sediment. Chemical and thermochemical techniques have been used to separate organic carbon when microfossils are not present. These techniques generally improve on bulk sediment dates, but they necessitate assumptions about the age spectra of specific molecules or compound classes and about the chemical heterogeneity of thermochemical separations. To address this, the Rafter Radiocarbon Laboratory has established parallel ramped pyrolysis oxidation (RPO) and ramped pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) systems to thermochemically separate distinct carbon fractions, diagnose the chemical composition of each fraction, and target suitable RPO fractions for radiocarbon dating. Three case studies of sediment taken from locations around Antarctica are presented to demonstrate the implementation of combined RPO-AMS and Py-GC-MS to provide more robust age determination in detrital sediment stratigraphy. These three depositional environments are good examples of analytical and interpretive challenges related to oceanographic conditions, carbon sources, and other factors. Using parallel RPO-AMS and Py-GC-MS analyses, we reduce the number of radiocarbon measurements required, minimize run times, provide context for unexpected 14C ages, and better support interpretations of radiocarbon measurements in the context of environmental reconstruction.

Mineralogical and geochemical variations among the Carboniferous and Cretaceous sedimentary kaolin deposits from Sinai provided an opportunity to examine the effect of the source area on compositions of the deposits. The Carboniferous kaolin deposits are mineralogically and geochemically heterogeneous. The Khaboba and Hasbar deposits consist of kaolinite, quartz, anatase, illite, chlorite, zircon, and leucoxene. The shale-normalized rare earth element (REE) patterns of the Khaboba deposit showed a slight LREE over HREE enrichment ((La/Yb)SN = 1.19–1.51) with a MREE depletion (Gd/Gd*SN = 0.51–0.75), while the Hasbar kaolin had a MREE enrichment. The Abu Natash kaolin deposit consisted of kaolinite, anatase, and a little quartz with larger TiO2, Cr, and V and smaller Zr and Nb contents compared to other Carboniferous deposits. The shale-normalized REE patterns of the Abu Natash deposit exhibited a positive Eu anomaly (Eu/Eu*SN = 1.28–1.40) and a MREE enrichment (Gd/Gd*SN = 1.41–2.05). The Cretaceous deposits were relatively homogeneous in terms of mineralogical composition and geochemistry and are composed of kaolinite, quartz, anatase, rutile, zircon, and leucoxene. The Cretaceous kaolin deposits showed mostly flat shale-normalized REE patterns with a variable LREE depletion.

The presence of illite and chlorite, the absence of rutile, large Zr and Nb contents, and the REE patterns suggested a component of weathered low-grade metasediments as a source for the Carboniferous deposits in the Khaboba and Hasbar areas, while the large Ti, Cr, and V, and small quartz contents indicated mafic source rocks for the Abu Natash deposit. The abundance of high-Cr rutile and the absence of illite and chlorite, and large Zr, Ti, Cr, and V contents suggested a mixture of medium- to high-grade metamafic and granitic rocks as source rocks for the Cretaceous kaolin deposits. The occurrence of alkaline rocks in the source of the deposits studied was identified by high-Nb contents and the presence of bastnaesite. The mineralogical and geochemical heterogeneity and lesser maturity of the Carboniferous deposits suggested local sources for each deposit and their deposition in basins close to the sources. The mineralogical and geochemical homogeneity and maturity of the Cretaceous deposits, on the other hand, indicated common sources for all deposits and their deposition in relatively remote basins.