Percentile Plots Research Articles

Epithermal Ag–Au mineralization at Galim-Legalgorou, Cameroon Volcanic Line: insights from alteration mineralogy and mineral chemistry of electrum and sphalerite

The Galim-Legalgorou area, located along the north-western branch of the Cameroon Volcanic Line (CVL), is known for artisanal gold mining and primary gold exploration, but the style and origin of the mineralization has not been fully described in the scientific literature. The close spatial association of the mineralization with Tertiary volcanic rocks raises the question of whether or not this is an epithermal system in a region where all previously studied gold occurrences have been classified as orogenic. In this contribution, we use ore mineral and alteration assemblage and mineral microchemistry to constrain the origin and evolution of the mineralization. Gold is alloyed mainly with Ag (max. 53.1 wt%) and show fineness values that vary 379 and 721 with an average of 455. A cumulative percentile plot of Ag concentrations in the cores of all electrum particles, and the observed step-change from Au-rich cores to more Ag-rich mantles in zoned electrum particles, suggest that the mineralization was deposited by two distinct hydrothermal fluid influxes. The observed ore mineral association-electrum, Se/Tl-acanthite, pyrite, Fe-rich sphalerite, ± galena; the measured FeS contents of sphalerite (average 23.1 mol%), and the presence of colloform banded chalcedony and hydrothermal breccia are all consistent with features of low sulfidation epithermal deposits. This study, therefore, demonstrates for the first time, the presence of significant low sulfidation epithermal Ag–Au mineralization on the CVL, an intracontinental rift region only previously known for orogenic gold mineralization.Graphical

Coronary artery calcium score percentiles: data from a single center in Turkey.

The coronary artery calcium (CAC) score is used in decision-making for preventive medications in patients with borderline clinical risk scores. Both absolute and percentile CAC scores can be used; however, a percentile CAC score is especially useful in young patients and women. The aim of this study is to present CAC score percentiles across age categories in women and men using a large database. Bilkent City Hospital database was screened for patients who underwent CAC score measurements between January 2021 and March 2022. Of the 4,487 patients, 546 were excluded due to 1) a history of coronary stent implantation or bypass surgery or 2) missing information regarding a history of revascularization or calcium scores. Therefore, the final study population included 3,941 participants. The percentiles for age categories within each sex were tabulated, and percentile plots were created for each sex using locally weighted scatterplot smoothing regression. The proportion of men included in the study was higher compared with that of women (57.09% vs. 42.91%). The mean age was 52.20 ± 11.11 years, and it was higher in women than in men (54.07 ± 10.47 vs. 50.80 ± 11.37, respectively; P < 0.001). A zero CAC score was observed in 2,381 (60.42%) patients; the percentage was higher in women than in men (68.60% vs. 54.27%; P < 0.001). When the cut-off value for the high-risk category was taken as the 75th percentile, a non-zero CAC score directly assigned a patient into the high-risk category in women aged <55 years and men aged <45 years. Percentile plots were also provided for each sex. In this large-scale study, including patients referred for CAC scoring and/or coronary computed tomography angiography, CAC score percentiles were provided for women and men across the selected age categories which may be in therapeutic decision-making. As an approximate rule of thumb, a non-zero CAC score corresponds to the high-risk category in women aged <55 years and in men aged <45 years.

Percentiles of predicted 10-year cardiovascular disease risk by sex and age in Brazil and their association with estimated risk of long-term atherosclerotic events

ObjectiveExpressing the cardiovascular disease (CVD) risk in relation to peers may complement the estimation of absolute CVD risk. We aimed to determine 10-year CVD risk percentiles by sex and age in the Brazilian population and evaluate their association with estimated long-term atherosclerotic CVD (ASCVD) risk. MethodsA cross-sectional analysis of baseline data from the ELSA-Brasil study was conducted in individuals aged 40–74 years without prior ASCVD. Ten-year CVD risk and long-term ASCVD risk were estimated by the WHO risk score and the Multinational Cardiovascular Risk Consortium tool, respectively. Ten-year risk percentiles were determined by ranking the calculated risks within each sex and age group. ResultsTen-year CVD risk versus percentile plots were constructed for each sex and age group using data from 13,364 participants (55% females; median age, 52 [IQR, 46–59] years). Long-term ASCVD risk was calculated in 12,973 (97.1%) participants. Compared to individuals at the <25th risk percentile, those at the ≥75th percentile had a greater risk of being in the highest quartile of long-term risk (ORs [95% CIs] 6.57 [5.18–8.30] in females and 11.59 [8.42–15.96] in males) in regression models adjusted for age, race, education, and 10-year CVD risk. In both sexes, the association between risk percentile and long-term risk weakened after age 50. A tool for calculating 10-year CVD risk and the corresponding percentile is available at https://bit.ly/3CzPUi6. ConclusionsWe established percentiles of predicted 10-year CVD risk by sex and age in the Brazilian population, which independently reflect the estimated long-term ASCVD risk in younger individuals.

A longitudinal comparison of emotional, behavioral and attention problems in autistic and typically developing children.

Mental health problems are elevated in autistic individuals but there is limited evidence on the developmental course of problems across childhood. We compare the level and growth of anxious-depressed, behavioral and attention problems in an autistic and typically developing (TD) cohort. Latent growth curve models were applied to repeated parent-report Child Behavior Checklist data from age 2-10 years in an inception cohort of autistic children (Pathways, N = 397; 84% boys) and a general population TD cohort (Wirral Child Health and Development Study; WCHADS; N = 884, 49% boys). Percentile plots were generated to quantify the differences between autistic and TD children. Autistic children showed elevated levels of mental health problems, but this was substantially reduced by accounting for IQ and sex differences between the autistic and TD samples. There was small differences in growth patterns; anxious-depressed problems were particularly elevated at preschool and attention problems at late childhood. Higher family income predicted lower base-level on all three dimensions, but steeper increase of anxious-depressed problems. Higher IQ predicted lower level of attention problems and faster decline over childhood. Female sex predicted higher level of anxious-depressed and faster decline in behavioral problems. Social-affect autism symptom severity predicted elevated level of attention problems. Autistic girls' problems were particularly elevated relative to their same-sex non-autistic peers. Autistic children, and especially girls, show elevated mental health problems compared to TD children and there are some differences in predictors. Assessment of mental health should be integrated into clinical practice for autistic children.

A visualization tool for continuous reference intervals based on GAMLSS

Abstract Reference intervals are an important component in the interpretation of medical laboratory findings. Especially in children and adolescents, their limits sometimes can change very rapidly with age. We suggest continuous methods to better represent the age-dependent progression of reference intervals. The generalized additive models for location, scale, and shape parameters (GAMLSS) from the R package gamlss generates continuous percentile plots of laboratory values. A user-friendly Shiny application called AdRI_GAMLSS (Age-dependent Reference Intervals), available at github.com/SandraKla/AdRI_GAMLSS, has been developed for this purpose. Using alkaline phosphatase (ALP) as an example, we obtain different smoothed percentile curves depending on the model used. We demonstrate the superiority of continuously modeled reference intervals compared to fixed age groups and provide the Shiny application AdRI_GAMLSS to make the technique easily accessible to clinicians and other experts.

Refreshing the Perinatal Periods of Risk: A New Reference Group and Nationwide Large-County-Level Analyses.

The Perinatal Periods of Risk approach (PPOR) is designed for use by communities to assess and address the causes of high fetal-infant mortality rates using vital records data. The approach is widely used by local health departments and their community and academic partners to inform and motivate systems changes. PPOR was developed and tested in communities based on data years from 1995 to 2002. Unfortunately, a national reference group has not been published since then, primarily due to fetal death data quality limitations. This paper assesses data quality and creates a set of unbiased national reference groups using 2014-2016 national vital records data. Phase 1 and Phase 2 analytic methods were used to divide excess mortality into six components and create percentile plots to summarize the distribution of 100 large US counties for each component. Eight states with poor fetal death data quality were omitted from the reference groups to reduce bias due to missing maternal demographic information. There are large Black-White disparities among reference groups with the same age and education restrictions, and these vary by component. PPOR results vary by region, maternal demographics, and county. The magnitude of excess mortality components varies widely across US counties. New national reference groups will allow more communities to do PPOR. Percentile plots of 100 large US counties provide an additional benchmark for new communities using PPOR and help emphasize problem areas and potential solutions.

Socio-economic segregation in European cities. A comparative study of Brussels, Copenhagen, Amsterdam, Oslo and Stockholm

ABSTRACT The purpose of this study is to compare socioeconomic segregation patterns and levels in Brussels, Copenhagen, Amsterdam, Oslo, and Stockholm with uniform measurements. Previous research has been hampered by conceptual and methodological shortcomings. We use harmonized datasets containing geocoded indicators based on a nearest-neighbors approach. Our analyses offer an unprecedented comparison of patterns and levels of socio-spatial inequalities in European capitals at multiple scales. Using maps, segregation indices and percentile plots, we find that for all cities, the segregation of the rich is much stronger than the segregation of the poor. Macro-scale poverty segregation is most prominent in Stockholm and Brussels, and quite low in Amsterdam, while macro-scale affluence segregation is most pronounced in Oslo. At micro-scales, Brussels and Stockholm stand out with very high local poverty concentrations, indicating high levels of polarization. We interpret differences in the light of spatial inequalities, welfare regimes, housing systems, migration and area-based interventions.

Effect of On-Street parking on pedestrian flow characteristics and level of service - an Indian viewpoint

Urbanization and automobile-oriented development have resulted in a significant increase in vehicular trips towards central business district (CBD) areas, consequently increasing the demand for on-street parking. In many Indian cities, on-street parking demand is regulated by an odd–even date on-street parking scheme. Under this scheme, sidewalks are subjected to fully and partially confined boundaries, affecting pedestrian movement and the level of service (LOS). Therefore, it becomes imperative to study the influence of on-street parking on pedestrian characteristics to design efficient pedestrian facilities. Pedestrian flow data were collected at three study sites in the CBD areas of three major metropolitan cities of Gujarat, India, using a videography technique. Investigation revealed an 18% reduction in walking speed for parking sidewalk face (PSF) compared to non-parking sidewalk face (NPSF), attributed to the variation in density and presence of parked vehicles. The influence of parked vehicles probed for a similar set of pedestrian densities revealed a 14% reduction in walking speed for PSF compared to NPSF. For the same geometric attributes of the sidewalk, PSF had a deteriorated pedestrian LOS at a given average condition, promulgating the need to develop separate LOS thresholds for PSF and NPSF. Based on the developed speed-density relationships for PSF and NPSF, the Monte-Carlo simulation was performed to facilitate the development of LOS thresholds. Based on the developed LOS thresholds and cumulative percentile plots, the study recommends LOS B as the design service level for sidewalks in the CBD area characterized by on-street parking.

Development and Validation of Automated Visual Field Report Extraction Platform Using Computer Vision Tools

Purpose: To introduce and validate hvf_extraction_script, an open-source software script for the automated extraction and structuring of metadata, value plot data, and percentile plot data from Humphrey visual field (HVF) report images.Methods: Validation was performed on 90 HVF reports over three different report layouts, including a total of 1,530 metadata fields, 15,536 value plot data points, and 10,210 percentile data points, between the computer script and four human extractors, compared against DICOM reference data. Computer extraction and human extraction were compared on extraction time as well as accuracy of extraction for metadata, value plot data, and percentile plot data.Results: Computer extraction required 4.9-8.9 s per report, compared to the 6.5-19 min required by human extractors, representing a more than 40-fold difference in extraction speed. Computer metadata extraction error rate varied from an aggregate 1.2-3.5%, compared to 0.2-9.2% for human metadata extraction across all layouts. Computer value data point extraction had an aggregate error rate of 0.9% for version 1, <0.01% in version 2, and 0.15% in version 3, compared to 0.8-9.2% aggregate error rate for human extraction. Computer percentile data point extraction similarly had very low error rates, with no errors occurring in version 1 and 2, and 0.06% error rate in version 3, compared to 0.06-12.2% error rate for human extraction.Conclusions: This study introduces and validates hvf_extraction_script, an open-source tool for fast, accurate, automated data extraction of HVF reports to facilitate analysis of large-volume HVF datasets, and demonstrates the value of image processing tools in facilitating faster and cheaper large-volume data extraction in research settings.

Understanding stream bank erosion and deposition in Iowa, USA: A seven year study along streams in different regions with different riparian land-uses

Agricultural activities such as row-cropping and grazing, have accelerated stream bank erosion. Accelerated stream bank erosion increases nonpoint source pollutants in aquatic ecosystems, significantly degrading them. Mitigating stream bank erosion is a priority worldwide, especially in agricultural watersheds. The objective of this study was to analyze the impacts of riparian land-use management on stream bank erosion and deposition, along with analyzing its temporal and spatial patterns. The study was conducted in three regions of Iowa (central, northeast and southeast) along 30 stream reaches adjacent to seven different riparian land-uses. The riparian land-uses were riparian forest buffers, grass filters, pastures with the cattle excluded from the stream, intensive rotational grazing, rotational grazing, continuous grazing and row crop fields. Seasonal erosion and deposition data (Spring, Summer and Autumn) were collected along these reaches for 5 years and yearly for the following two years. To analyze the data, conventional statistical methods (ANOVA and Tukey's test) along with innovative techniques (percentile plots, cumulative erosion curves and bubble charts) were utilized. Based on the analysis, of this extensive in time (seven years) and large in size (1500 pins measured 17 times in three regions) field dataset, major results were obtained in regard to stream bank erosion in Iowa, USA. Stream banks exhibited high year-to-year variation in erosion and deposition showcasing the need for long-term datasets to better understand stream bank erosion and deposition. Seasonal erosion, also had high variability with Spring recording the most erosion followed by Summer and Autumn. Certain seasons exhibited high stream bank erosion indicating that managers need to focus on these seasons, to reduce erosion effectively. In addition, seasonal measurements can highlight depositional events that might be masked with annual measurements. Riparian land-uses significantly impacted stream bank erosion. Riparian forest buffers and grass filters significantly mitigated stream bank erosion while traditional agricultural practices like continuous grazing and row-crop agriculture had accelerated stream bank erosion. Finally, the percentile plots, cumulative erosion curves and bubble charts captured some stream bank responses that would have been unnoticed using conventional statistical methods, allowing decision makers, stakeholders and the general public, to support and approve measures to mitigate this environmental problem. Nature-based solutions utilizing riparian perennial vegetation can sustainably mitigate stream bank erosion.

Normal axillary thickness thresholds as a metric for nutritional status of children

IntroductionChildhood pneumonia is a major cause of death in the 3rd world, and undernourishment increases the severity of the condition. We considered axillary thickness as a simple measurement to evaluate nutritional status that can be performed simultaneously with lung ultrasound. Our goal was to determine the distribution of axillary thickness in a cohort of children to determine a threshold for malnutrition. MethodsClinical databases were scanned to identify chest computed tomograms (CT) in children between the ages of 0 and 5 years with non-debilitating disease. The bilateral axillary thicknesses of the cohort were determined using equivalent width, and these measurements were segmented by age, sex, and laterality to determine cutoff thresholds. Data was evaluated using single factor analysis of variance (ANOVA) and 5th percentile analysis to determine the lower bound thresholds of axillary thickness. Results247 scans met inclusion criteria. ANOVA demonstrated no significant differences in the mean measurements in the 5 groups (p = 0.377). 95% confidence limits on the 5th percentile plots showed an axillary thickness of 1.5 cm was a reasonable threshold for malnutrition detection for all age groups and sexes except for males between 0 and 1 years old where a 1.1 cm threshold may be required. DiscussionCT scans of the chests in a cohort of children without debilitating disease revealed a remarkably uniform axillary thickness threshold for malnutrition assessment of 1.5 cm. This suggests that there may be a threshold for nutritional assessment for children undergoing lung ultrasound scans for childhood pneumonia.

Dose Selection Process for Younger Children Participating in a Phase 3 Study to Evaluate the Efficacy and Safety of Rivipansel (GMI-1070) in the Treatment of Vaso-Occlusive Crisis in Hospitalized Patients with Sickle Cell Disease

Background: Rivipansel is a pan-selectin inhibitor in development for the treatment of sickle cell disease (SCD) vaso-occlusive crisis (VOC). A single phase 3 study was planned to evaluate the efficacy and safety of rivipansel (GMI-1070) in the treatment of VOC in hospitalized patients with SCD. Selection of the dose to be used in this phase 3 study was based on the efficacy, safety, and pharmacokinetic (PK) results from the rivipansel phase 2 study. Modeling and Simulation (M&S) was used to determine the dosing for adults and children aged >6 years with SCD. To ensure that the predicted drug exposure is actually achieved in patients aged 6-11 years (cohort 2), we conducted a blinded review of the PK data obtained from several subjects enrolled in cohort 2. The methodology for this evaluation is presented here.Methods: Pharmacokinetic data for 109 subjects receiving doses of 2 to 40 mg/kg in 4 previous studies (3 Phase 1 and 1 Phase 2) were integrated to build a 3-compartment model, which was used to perform simulations to aid dose selection. As rivipansel is almost entirely renally excreted, the simulations of clearance considered renal function as well as hyperfiltration, as this type of altered renal filtration is common in SCD patients. This model allowed for scaling of the PK exposure from the model developed in adults and older children (aged 12-17 years) (Tammara BK, Harnisch LO. CPT Pharmacometrics Syst Pharmacol 2017;6:845-54) into the model for younger children (aged 6-11 years). Simulations from the model in the adult and pediatric population are presented in Figure 1.To confirm the predicted exposure in cohort 2, in particular their average concentration at steady-state (Cavg,ss), age- and weight-dependent cumulative distribution functions (CDFs) of parameters in the population PK model (eg, CL Vss) were derived for the first 6 actively treated children. During this blinded review, concentration time profiles for these children were generated and empirical Bayesian estimates (EBEs) for their corresponding Cavg,ss were derived. The percentiles in which the EBEs fell within the simulated CDFs from the model were used to guide decisions for a potential dose adjustment. This process is outlined in the flow chart in Figure 2 and in the percentile plot diagram shown in Figure 3.Results: The PK data from the Phase 2 study supported fixed flat dosing for patient aged 12 years and older. Pharmacokinetic M&S predicted that a loading dose of 1680 mg followed by a maintenance dose of 840 mg every 12 hours would result in exposures similar to those observed with the lower dose used in the Phase 2 study, such that a minimum plasma concentration >10 μg/mL would be maintained throughout the dosing interval. For patients in cohort 2, weight-based dosing was considered, as it is the most conservative approach, given that children in this age range have not been studied previously. For each dosing regimen tested, the simulated demographic target distribution in pediatric SCD patients was used to derive concentration-time profiles. A summary of the Cavg,ss distribution across different ages is shown in Figure 1. The simulations showed that for children aged 6-11 years, a 40-mg/kg loading dose (maximum 1680 mg) followed by 20 mg/kg every 12 hours (maximum 840 mg) would likely result in concentrations similar to those observed with the 20/10 mg/kg dosing used in adults in the Phase 2 study. To confirm the validity of the exposure predictions, PK assessments were performed in the Phase 3 study and a blinded interim analysis of pediatric exposures was conducted.Conclusions: A population PK model for rivipansel has been developed, applicable to the whole target SCD population of adults and children older than 12 years. Its applicability in children aged 6-11 years is under investigation as part of the ongoing Phase 3 study, and interim assessments of the PK exposure have been done in small cohorts of 6 patients. The corresponding decision framework has been implemented, exercised successfully, with the results of potential dose adaptations to be published once the Phase 3 study has been concluded. [Display omitted] DisclosuresTammara:Pfizer Inc.: Employment. Shafer:Pfizer Inc.: Employment. Harnisch:Pfizer Inc.: Employment.

Percentile reference curves for normal pancreatic dimensions in Indian children

Objectives:This study aims at determining the normal pancreatic dimensions in pediatric age groups considering demographic parameters and thus developing percentile reference curves for normal pancreatic dimensions in Indian children.Setting and Design:It is a cross-sectional study.Materials and Methods:A hospital-based cross-sectional study was planned at a children hospital during July 2016–December 2017, in which the pancreatic dimensions of 1078 normal children in the age range of 1 month to 19 years were obtained through abdominal ultrasonography (USG). The demographic details like age and gender were obtained for each child.Statistical Analysis Used:Percentile reference curves were obtained with reference to age for each gender type independently. Generalized additive models for location, scale, and shape were used to obtain percentile plots for each pancreatic part.Results:The mean age of children was 6.65 ± 4.43 years and the male-to-female ratio was 1.63:1. The head, body, and tail dimensions increased with the age. For head, up to 25th percentile, the curves were similar for both genders, while subsequent curves were higher in males as compared to females. Similar was the observation for body of pancreas. For tail, up to 75th percentile, the curves were similar for both genders.Conclusion:The normal ranges can be supportive in diagnosis of illness related to pancreas. The dimensions within 5–95th percentile along with iso-echogenicity can be regarded as normal, while the dimensions beyond these limits along with change of echogenicity can be suspected for pancreatic disorders.

Evaluation of the Turkish Highway Network Analysis With Traffic Data

As a complex geospatial structure, Turkish national highway transportation network is studied by the means of network science. We used the dataset retrieved from the KGM (Karayollari Genel Mudurlugu) maps with a hand-driven process. The dataset labels the junctions in the map as nodes, and the roads between these junctions as edges. We outlined the statistical properties of the Turkish highway transportation network by the means of eigenvector, betweenness, closeness centrality, modularity and eccentricity measures, while comparative percentile plots between these measures are also performed. We investigated the correlation of these parameters with the traffic volume, and outlined that only eccentricity measure is correlated with the traffic volume. We also investigated the degree correlations of the network and found that the network displays disassortative mixing behavior, meaning that nodes with high degrees tend to connect with lower degree nodes, and vice versa. This property is consistent with the recent studies of transportation networks, as well as various types of real networks like Internet, World-Wide Web, protein interactions, neural network etc.

A Tale of Two Soundscapes: Comparing the Acoustic Characteristics of Urban Versus Pristine Coastal Dolphin Habitats in Western Australia

Underwater noise environments are increasingly being considered in marine spatial planning and habitat quality assessments. Although the overall aim of regulation is to quieten anthropogenically noise-rich habitats whilst maintaining pristine habitats free of man-made noise, effective management plans require knowledge upon which to base decisions. This is particularly true for managers of acoustically specialised species. This study aimed to compare the acoustic environment of coastal dolphins in two locations within Western Australia by comparing a ‘pristine’ habitat (Roebuck Bay) with an ‘urban’ habitat (Fremantle Inner Harbour). Autonomous underwater acoustic recorders collected approximately 940 and 1080 h of data from these two sites, respectively. Additionally, in Roebuck Bay opportunistic in situ recordings with concurrent visual observations were collected in the presence of two dolphin species. Acoustic data were assessed via weekly spectrograms, power spectrum density percentile plots and probability densities, octave band levels, broadband noise levels, and generalised estimating equations. Results indicated that the two sites had highly contrasting acoustic environments. In Roebuck Bay, the local soundscape was dominated by biotic sounds, with only sporadic vessel noise. However, in Fremantle Inner Harbour, anthropogenic noise was prevalent. On average, Roebuck Bay was 20 dB quieter than the Fremantle Inner Harbour over the frequency band 10 Hz–11 kHz. Dolphin communications had a greater potential to be masked in Fremantle Inner Harbour than in Roebuck Bay based on elevated anthropogenic noise levels. If noise levels were to increase in Roebuck Bay, coastal dolphins may show behavioural and/or acoustical responses as observed at other locations.

Uncovering the differences in linguistic network dynamics of book and social media texts.

Complex network studies span a large variety of applications including linguistic networks. To investigate the differences in book and social media texts in terms of linguistic typology, we constructed both sequential and sentence collocation networks of book, Facebook and Twitter texts with undirected and weighted edges. The comparisons are performed using the basic parameters like average degree, modularity, average clustering coefficient, average path length, diameter, average link weight etc. We also presented the distribution graphs for node degrees, edge weights and maximum degree differences of the pairing nodes. The degree difference occurrences are furtherly detailed with the grayscale percentile plots with respect to the edge weights. We linked the network analysis with linguistic aspects like word and sentence length distributions. We concluded that linguistic typology demonstrates a formal usage in book that slightly deviates to informal in Twitter. Facebook interpolates between these media by the means of network parameters, while the informality of Twitter is mostly influenced by the character limitations.

Underwater Sound in an Urban Estuarine River: Sound Sources, Soundscape Contribution, and Temporal Variability

Human waterborne activities emit noise into the marine environment. This is of particular concern with regard to the potential impact on marine fauna such as cetaceans due to their acoustic specialisations. The Swan-Canning River system in Western Australia is home to a resident community of Indo-Pacific bottlenose dolphins (Tursiops aduncus), but is also a site regularly used for various human activities. As underwater noise levels increasingly become considered as an indicator of habitat quality, there is a need to characterise the soundscapes of such areas with regard to their cetacean fauna. This study aimed to provide a description of a site within the river system known as “The Narrows”. Acoustic data were collected over a six-week period with an autonomous underwater acoustic recorder. These data were analysed using a combination of weekly spectrograms, power spectral density percentile plots, 1/3 octave band levels, and generalised estimating equations to identify prominent soundscape contributors and investigate temporal patterns in their occurrence. The soundscape was found to be strongly influenced by wind, snapping shrimp, and vessel traffic, with the sounds of bridge traffic, waves, fish, machinery, dolphins, and precipitation also contributing to the acoustic environment. Furthermore, three of these sound sources (boats, waves, and fish) were found to vary at a range of temporal scales. These results take a vital step in characterising the acoustic habitat of this river system, highlighting the need to consider temporal patterns when assessing the composition of underwater soundscapes.

A 4-year prospective study of the progression of periodontal disease in a rural Chinese population

ObjectivesThe natural progression of periodontitis in the Chinese population is not well researched. We investigated the progression of periodontal disease over 4 years in 15–44-year-old Chinese villagers with no access to regular dental care. MethodsIn 1992, 486 villagers were enrolled, and in 1996, 413 villagers were re-examined. Probing depth (PD) and clinical attachment level (CAL) were examined at six sites per tooth. Sites with ΔCAL ≥3mm were defined as active sites. Cross-sectional and longitudinal analyses were performed using means and percentile plots. ResultsThe mean CAL increased by 0.26mm over 4 years. The incidence of periodontitis (at least one site with CAL ≥3mm) was 8%. The incidence of periodontitis among those with no periodontal disease at baseline was 44.9%. Seventy-eight percent of the subjects had at least one active site. In the 15–24-year group, 244 of 401 active sites had gingival recession, while only 51 active sites had both gingival recession and deeper pockets. In the 25–34-year and 35–44-year groups, almost one-third of the active sites (329/1087) and more than one-third of the active sites (580/1312) respectively had a combination of gingival recession and deeper pockets. ConclusionsIn this study, we demonstrated that in Chinese population without regular dental care, both the initiation of periodontitis and progression of previously existed periodontitis contributed to the natural progression of periodontitis and periodontal pocketing played a greater role with age increasing. Clinical significanceThis rare study reports the natural progression of periodontal disease in a group of Chinese villagers (15–44 years) with virtually no access to regular dental care.

Estimating and evaluating Value‐at‐Risk forecasts based on realized variance: empirical evidence from ICE Brent Crude oil futures

AbstractThis paper is the first to use the concept of realized volatility to forecast Value‐at‐Risk (VaR) for ICE Brent Crude oil futures. We examine sensitivities in the VaR forecasts across intra‐daily sampling frequency used to calculate realized volatility. We evaluate the VaR forecasts using Christoffersen's test for conditional coverage on quantiles of particular interest. Additionally, we examine a percentile–percentile plot of the VaR forecasts for all percentiles. The main empirical results show that very good VaR forecasts can be obtained using Gaussian critical values in combination with volatility forecasts based on realized volatility. An examination of the sampling frequency suggests that the most accurate VaR forecasts are obtained with a sampling frequency of between 1 and 10 min. This has important implications for practitioners operating in the financial oil sector.

Structural Growth Trajectories and Rates of Change in the First 3 Months of Infant Brain Development

The very early postnatal period witnesses extraordinary rates of growth, but structural brain development in this period has largely not been explored longitudinally. Such assessment may be key in detecting and treating the earliest signs of neurodevelopmental disorders. To assess structural growth trajectories and rates of change in the whole brain and regions of interest in infants during the first 3 months after birth. Serial structural T1-weighted and/or T2-weighted magnetic resonance images were obtained for 211 time points from 87 healthy term-born or term-equivalent preterm-born infants, aged 2 to 90 days, between October 5, 2007, and June 12, 2013. We segmented whole-brain and multiple subcortical regions of interest using a novel application of Bayesian-based methods. We modeled growth and rate of growth trajectories nonparametrically and assessed left-right asymmetries and sexual dimorphisms. Whole-brain volume at birth was approximately one-third of healthy elderly brain volume, and did not differ significantly between male and female infants (347 388 mm3 and 335 509 mm3, respectively, P = .12). The growth rate was approximately 1%/d, slowing to 0.4%/d by the end of the first 3 months, when the brain reached just more than half of elderly adult brain volume. Overall growth in the first 90 days was 64%. There was a significant age-by-sex effect leading to widening separation in brain sizes with age between male and female infants (with male infants growing faster than females by 200.4 mm3/d, SE = 67.2, P = .003). Longer gestation was associated with larger brain size (2215 mm3/d, SE = 284, P = 4×10-13). The expected brain size of an infant born one week earlier than average was 5% smaller than average; at 90 days it will not have caught up, being 2% smaller than average. The cerebellum grew at the highest rate, more than doubling in 90 days, and the hippocampus grew at the slowest rate, increasing by 47% in 90 days. There was left-right asymmetry in multiple regions of interest, particularly the lateral ventricles where the left was larger than the right by 462 mm3 on average (approximately 5% of lateral ventricular volume at 2 months). We calculated volume-by-age percentile plots for assessing individual development. Normative trajectories for early postnatal brain structural development can be determined from magnetic resonance imaging and could be used to improve the detection of deviant maturational patterns indicative of neurodevelopmental disorders.