Tag: statistics

Neural Netw. 2021 Aug 26;144:164-175. doi: 10.1016/j.neunet.2021.08.024. Online ahead of print.

ABSTRACT

Modern feedforward convolutional neural networks (CNNs) can now solve some computer vision tasks at super-human levels. However, these networks only roughly mimic human visual perception. One difference from human vision is that they do not appear to perceive illusory contours (e.g. Kanizsa squares) in the same way humans do. Physiological evidence from visual cortex suggests that the perception of illusory contours could involve feedback connections. Would recurrent feedback neural networks perceive illusory contours like humans? In this work we equip a deep feedforward convolutional network with brain-inspired recurrent dynamics. The network was first pretrained with an unsupervised reconstruction objective on a natural image dataset, to expose it to natural object contour statistics. Then, a classification decision head was added and the model was finetuned on a form discrimination task: squares vs. randomly oriented inducer shapes (no illusory contour). Finally, the model was tested with the unfamiliar “illusory contour” configuration: inducer shapes oriented to form an illusory square. Compared with feedforward baselines, the iterative “predictive coding” feedback resulted in more illusory contours being classified as physical squares. The perception of the illusory contour was measurable in the luminance profile of the image reconstructions produced by the model, demonstrating that the model really “sees” the illusion. Ablation studies revealed that natural image pretraining and feedback error correction are both critical to the perception of the illusion. Finally we validated our conclusions in a deeper network (VGG): adding the same predictive coding feedback dynamics again leads to the perception of illusory contours.

PMID:34500255 | DOI:10.1016/j.neunet.2021.08.024

Arch Oral Biol. 2021 Sep 3;131:105253. doi: 10.1016/j.archoralbio.2021.105253. Online ahead of print.

ABSTRACT

OBJECTIVE: This retrospective radiographic controlled study investigates the dental phenotype in patients with Crouzon syndrome to determine if differences are observed as suggested by the FGFR2^C342Y/+ Crouzon mouse models, and whether these models could be of interest to study the role of this mutation in tooth development.

DESIGN: We assessed dental phenotype using dedicated linear measurements in 22 children with Crouzon syndrome and compared tooth morphology in both primary and permanent dentitions to an age-matched control group. Descriptive statistics were performed with “Sex” and “Age” as covariates for the permanent tooth models and “Sex” only for the primary tooth models, to take into account potential confounding factors.

RESULTS: We showed that permanent but not primary tooth dimensions were globally reduced in Crouzon syndrome, without microdontia. In permanent dentition, crown height, mesiodistal and faciolingual cervical diameters were reduced by 6.3%, 5.7% and 5.5% respectively (p < 0.05).

CONCLUSION: Our results underline the implication of Fibroblast Growth Factor Receptor 2 (FGFR2) in dental development of humans and contribute to support FGFR2^C342Y/+ Crouzon mouse models as partial replicas of this condition, including in the oral region.

PMID:34500259 | DOI:10.1016/j.archoralbio.2021.105253

Drug Alcohol Depend. 2021 Sep 1;228:109007. doi: 10.1016/j.drugalcdep.2021.109007. Online ahead of print.

ABSTRACT

BACKROUND: Research suggests that the social media platforms popular on college campuses may reflect, reinforce, and even exacerbate heavy drinking practices among students. The present study was designed to directly examine: (1) whether exposure to alcohol-related content on social media diminishes the efficacy of a traditional web-based personalized normative feedback (PNF) alcohol intervention among first-year drinkers; and (2) if social media inspired features and digital game mechanics can be integrated into a PNF intervention to combat social media-based alcohol influence and increase efficacy.

METHOD: Alcohol experienced first-year college students (N = 223) completed a pre-survey that assessed exposure to alcohol-related content and social media and were randomized to 1 of 3 web-based alcohol PNF conditions (traditional, gamified only, or social media inspired gamified). One month later, participants’ alcohol consumption was reassessed.

RESULTS: Among participants who received traditional PNF, social media-based alcohol exposure interacted with pre-intervention drinking such that traditional PNF was less effective in reducing drinking among heavier drinkers reporting greater exposure to alcohol-related social media content. Further, when regression models compared the efficacy of all three conditions, the social media inspired gamified PNF condition was significantly more effective in reducing drinking than was traditional PNF among moderate and heavy drinkers reporting greater exposure to alcohol on social media.

CONCLUSION: Although additional research is needed, these findings suggest that representing the population of students on whom normative statistics are based with social media-like user avatars and profiles may enhance the degree to which alcohol PNF is relatable and believable among high-risk students.

PMID:34500245 | DOI:10.1016/j.drugalcdep.2021.109007

Virology. 2021 Sep 3;563:88-97. doi: 10.1016/j.virol.2021.08.015. Online ahead of print.

ABSTRACT

Two experimental challenge studies were conducted to evaluate the pathogenesis of a porcine parainfluenza virus type 1 (PPIV-1) isolate. Four-week-old conventional (CON) pigs were challenged in Study 1 and six-week-old caesarean derived/colostrum deprived (CDCD) pigs were challenged in Study 2. Results indicate that PPIV-1 shedding and replication occur in the upper and lower respiratory tracts of CON and CDCD pigs as detected by RT-qPCR and immunohistochemistry. Mild macroscopic lung lesions were observed in CON pigs but not in CDCD pigs. Microscopic lung lesions were mild and consisted of peribronchiolar lymphocytic cuffing and epithelial proliferation in CON and CDCD pigs. Serum neutralizing antibodies were detected in the CON and CDCD pigs by 14 and 7 days post inoculation, respectively. This study provides evidence that in spite of PPIV-1 infection and replication in challenged swine, significant clinical respiratory disease was not observed.

PMID:34500147 | DOI:10.1016/j.virol.2021.08.015

Placenta. 2021 Sep 4;114:83-89. doi: 10.1016/j.placenta.2021.09.001. Online ahead of print.

ABSTRACT

INTRODUCTION: Research into the role of ultrasound elastography to assess compromised placental tissue is ongoing. There is particular interest in evaluating its potential in the investigation of changes associated with uteroplacental dysfunction. To date, there is limited data on how different maternal and fetal considerations, such as advancing gestational age, amniotic fluid Index (AFI) and maternal body mass index (BMI) may influence shear wave velocity (SWV) measurements. This study aimed to evaluate longitudinal changes in SWV throughout gestation and model these changes with other developing fetal and maternal physiological and biological characteristics.

METHODS: The study utilised 238 singleton pregnancies and collected longitudinal data at repeated intervals in the 3rd trimester representing 629 individual data points. Linear mixed model regression analysis was used to identify significant predictors for SWV.

RESULTS: From a total of ten variables selected for modelling, only gestational age, AFI, BMI, and sample depth were found to be significant predictors of placental SWV, and gestational age and AFI were found to have only a minimal impact on SWV.

DISCUSSION: Sophisticated statistical modelling demonstrates that many of the expected maternal and fetal changes in the 3rd trimester have no or minimal impact on placental SWV. Understanding which factors influence placental SWV is essential to ascertain the technique’s utility in managing pregnancies complicated by placental dysfunction in the future.

PMID:34500214 | DOI:10.1016/j.placenta.2021.09.001

J Contam Hydrol. 2021 Sep 3;243:103887. doi: 10.1016/j.jconhyd.2021.103887. Online ahead of print.

ABSTRACT

Future changes in drought events are critical for risk assessment and associated policymaking. In this study, the future changes in meteorological droughts in Henan Province, China are explored. Random forests downscaling model is first constructed based on ERA5 reanalysis data and meteorological observations. The model is validated using evaluation indices such as R² and RMSE, and is shown to be able to capture the relationship between large-scale predictors and monthly precipitation. The validated random forests downscaling model is driven by multiple global climate models (GCMs) from the Phase 6 of the Coupled Model Intercomparison Project (CMIP6) under three emission scenarios for projecting three future drought characteristics (duration, frequency, and intensity). Results show that drought frequency decreases in most areas of Henan while drought duration and intensity increase in various degrees. Some differences are also observed among different emission scenarios, especially under SSP2-4.5, where the magnitudes of changes in drought duration and intensity are lower relative to other scenarios. The decrease in drought frequency in most areas is found to be caused by increases in monthly mean precipitation in this study. Changes in drought duration and intensity are related to a combination of increases in precipitation mean and variability.

PMID:34500145 | DOI:10.1016/j.jconhyd.2021.103887

J Vet Emerg Crit Care (San Antonio). 2021 Sep 9. doi: 10.1111/vec.13138. Online ahead of print.

ABSTRACT

OBJECTIVE: To report the rate of fluid production at the time of removal of thoracostomy tubes placed intraoperatively and to determine the association of this rate with specific patient factors, surgical factors, or clinical diagnosis. The secondary objective was to determine whether identification of pleural effusion within 2 weeks of thoracostomy tube removal was associated with the same variables.

DESIGN: Retrospective study.

SETTING: University teaching hospital.

ANIMALS: One hundred eighty-five client-owned dogs with thoracostomy tubes placed intraoperatively between January 2010 and March 2017.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: Thoracostomy tubes were removed at a median fluid production of 0.09 mL/kg/h (range, 0-7.0 m L/kg/h). Median fluid production at the time of thoracostomy tube removal was significantly higher in dogs with preoperative pleural effusion compared to dogs without preoperative pleural effusion (0.21 vs 0.05 mL/kg/h; P = 0.0001) and in dogs that had a median sternotomy compared to dogs that had a lateral thoracotomy (0.14 vs 0.09 mL/kg/h; P = 0.04). Of the 169 dogs available for follow-up, 12 (7.1%) had pleural effusion within 2 weeks of removal of the thoracostomy tube. Detection of pleural effusion during the follow-up period was significantly associated with the presence of preoperative pleural effusion (P = 0.0019) and the diagnosis (P = 0.01). A greater proportion of dogs with a lung lobe torsion (4/9, 44.4%) and idiopathic chylothorax (2/7, 28.5%) had pleural effusion within 2 weeks compared to other diagnoses. Reintervention was performed in 4.7% of dogs.

CONCLUSIONS: Thoracostomy tubes were removed at pleural fluid production rates that frequently exceeded current veterinary guidelines. However, the fluid production rate at the time of thoracostomy tube removal was not associated with the detection of pleural effusion within 2 weeks of thoracostomy tube removal, and the overall need for reintervention following thoracostomy tube removal was low (4.7%).

PMID:34499801 | DOI:10.1111/vec.13138

Environ Microbiol. 2021 Sep 9. doi: 10.1111/1462-2920.15765. Online ahead of print.

ABSTRACT

Global warming affects the aquatic ecosystems, accelerating pathogenic microorganisms’ and toxic microalgae’s growth and spread in marine habitats, and in bivalve molluscs. New parasite invasions are directly linked to oceanic warming. Consumption of pathogen-infected molluscs impacts human health at different rates, depending, inter alia, on the bacteria taxa. It is therefore necessary to monitor microbiological and chemical contamination of food. Many global cases of poisoning from bivalve consumption can be traced back to Mediterranean regions. This paper’s aim is to examine the marine bivalve’s infestation rate within the scope of climate change, as well as to evaluate the risk posed by climate change to bivalve welfare and public health. Biological and climatic data literature review was performed from international scientific sources, Greek authorities and State organizations. Focusing on Greek aquaculture and bivalve fisheries, high risk index pathogenic parasites and microalgae were observed during summer months, particularly in Thermaikos Gulf. Considering the climate models that predict further temperature increases, it seems that marine organisms will be subjected in the long-term to higher temperatures. Due to the positive linkage between temperature and microbial load, the marine areas most affected by this phenomenon are characterized as “high risk” for consumer health. This article is protected by copyright. All rights reserved.

PMID:34499795 | DOI:10.1111/1462-2920.15765

J Vet Emerg Crit Care (San Antonio). 2021 Sep 9. doi: 10.1111/vec.13135. Online ahead of print.

ABSTRACT

OBJECTIVE: To develop a population-derived, parsimonious, and objective risk stratification model for dogs following trauma and compare its predictive performance to the animal trauma triage (ATT) score.

DESIGN: Observational cohort study using data from the American College of Veterinary Emergency and Critical Care Veterinary Committee on Trauma (VetCOT) trauma registry acquired between September 2013 and October 2017.

SETTING: Nine Level I and Level II veterinary trauma centers.

ANIMALS: Nine hundred eighty-four dogs assessed within 24 h of traumatic injury.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: Patient mortality was 10.8%. The VetCOT model was constructed based on 4 variables: plasma lactate and ionized calcium obtained within 6 h of admission, and presence or absence of clinical signs consistent with either head or spinal trauma. The VetCOT score had good discriminatory performance (AUROC = 0.87, 95% CI = 0.83-0.91) comparable to that of the 6 variable ATT score for the same population (area under the receiver operator characteristic [AUROC] = 0.87; 95% CI, 0.84-0.90). No statistical difference in discriminatory performance between the 2 scores was identified (P = 0.98). The VetCOT score showed good calibration on this population (Hosmer-Lemeshow test P = 0.93), whereas the ATT score failed to calibrate (P = 0.02) due to overprediction of mortality at low scores. Sensitivity and specificity for outcome of the VetCOT score at a risk probability cutoff of 0.5 for this population were 28.97% and 97.95%, respectively.

CONCLUSIONS: The VetCOT score is a more parsimonious model with comparable discriminatory performance and superior calibration to the ATT score for risk stratification in dogs following trauma. Further prospective validation studies are required to confirm the discriminatory performance of the VetCOT score.

PMID:34499798 | DOI:10.1111/vec.13135

Am J Hum Biol. 2021 Sep 9:e23679. doi: 10.1002/ajhb.23679. Online ahead of print.

ABSTRACT

BACKGROUND: Digit ratio (2D:4D), a putative marker of prenatal testosterone, is a negative correlate of sports, athletic, and fitness performance.

OBJECTIVES: To describe the relationship between 2D:4D and vertical jump performance in athletes.

METHODS: Sixty-one Division I American Football players from a Midwestern U.S. university had their 2D:4D measured digitally and their vertical jump performance measured using jump mechanography. The primary outcome was jump height, with secondary outcomes depicting jump execution also recorded. Linear relationships between 2D:4D and vertical jump performance were quantified using partial correlations adjusted for age, height, mass, and ethnicity.

RESULTS: 2D:4D was a statistically significant weak negative correlate of jump height (partial r [95% confidence interval]: -0.26 [-0.48, -0.01]), indicating that athletes with lower 2D:4Ds (i.e., relatively longer 4th digits) jumped higher. Relationships with jump execution variables were negligible to weak and negative, but not statistically significant.

CONCLUSIONS: The significant relationship between 2D:4D and jump height probably reflects both the long-term organizational and short-term activational benefits of testosterone. Therefore, 2D:4D may be a useful indicator of explosive strength among young athletes.

PMID:34499783 | DOI:10.1002/ajhb.23679