Wastewater-based epidemiology in hazard forecasting and early-warning systems for global health risks.

With the advent of the SARS-CoV-2 pandemic, Wastewater-Based Epidemiology (WBE) has been applied to track community infection in cities worldwide and has proven succesful as an early warning system for identification of hotspots and changingprevalence of infections (both symptomatic and asymptomatic) at a city or sub-city level. Wastewater is only one of environmental compartments that requires consideration. In this manuscript, we have critically evaluated the knowledge-base and preparedness for building early warning systems in a rapidly urbanising world, with particular attention to Africa, which experiences rapid population growth and urbanisation. We have proposed a Digital Urban Environment Fingerprinting Platform (DUEF) - a new approach in hazard forecasting and early-warning systems for global health risks and an extension to the existing concept of smart cities. The urban environment (especially wastewater) contains a complex mixture of substances including toxic chemicals, infectious biological agents and human excretion products. DUEF assumes that these specific endo- and exogenous residues, anonymously pooled by communities' wastewater, are indicative of community-wide exposure and the resulting effects. DUEF postulates that the measurement of the substances continuously and anonymously pooled by the receiving environment (sewage, surface water, soils and air), can provide near real-time dynamic information about the quantity and type of physical, biological or chemical stressors to which the surveyed systems are exposed, and can create a risk profile on the potential effects of these exposures. Successful development and utilisation of a DUEF globally requires a tiered approach including: Stage I: network building, capacity building, stakeholder engagement as well as a conceptual model, followed by Stage II: DUEF development, Stage III: implementation, and Stage IV: management and utilization. We have identified four key pillars required for the establishment of a DUEF framework: (1) Environmental fingerprints, (2) Socioeconomic fingerprints, (3) Statistics and modelling and (4) Information systems. This manuscript critically evaluates the current knowledge base within each pillar and provides recommendations for further developments with an aim of laying grounds for successful development of global DUEF platforms.

Effects of lip revision surgery in cleft lip/palate patients.

The decision for lip revision surgery in patients with repaired cleft lip/palate is based on surgeons' subjective evaluation of lip disability. An objective evaluation would be highly beneficial for the assessment of surgical outcomes. In this study, the effects of lip revision on circumoral movements were objectively quantified. The hypothesis was that lip revision increases scarring and impairment. The study was a non-randomized clinical trial that included patients with cleft lip who had revision, patients with cleft lip who did not, and non-cleft control individuals. Three-dimensional facial movements were measured. Revision patients were measured before and after surgery. Other individuals were measured at similar intervals. Regression models were fit to summary measurements, and changes were modeled. Patients with repaired cleft lip/palate had fewer mean movements than control individuals. Lip revision did not worsen mean movements; however, individual patients' movements varied from 'improvement' to 'no change' to 'worse' relative to those of control individuals.

Three dimensional analysis of facial movement in normal adults: influence of sex and facial shape.

The aim of this study was to quantify facial movements in a sample of normal adults and to investigate the influence of sex and facial shape on these movements. The study sample consisted of 50 healthy adult subjects, 25 males and 25 females (age: mean = 27.3 years; range = 23-39 years). A video-based tracking system was used to track small-diameter retroreflective markers positioned at specific facial sites. Subjects were instructed to make 7 maximum facial animations from rest, and the facial movements for each animation were characterized as the vectors of maximum displacement. Hotelling's T2 was used to test for significant sex differences in facial movements. In order to determine the effects of facial shape on facial movements, an index of facial shape was first calculated for each subject, and then a mixed-model ANOVA was used with facial shape (index), sex, and the interaction between facial shape and sex as fixed effects and subject as a random effect. The results demonstrated specific movement patterns for each animation. In general, males had larger movements than females and facial shape had a small but significant effect on facial movements. By comparing patient movements with the data from this large normative sample, the utility of this method to assess region-specific movement deficits was demonstrated.

Three-dimensional nasolabial displacement during movement in repaired cleft lip and palate patients.

The objective of this study was two-fold: (1) to explore the suitability of a novel modified Procrustes fit method to adjust data for head motion during instructed facial movements, and (2) to compare the adjusted data among repaired unilateral (n = 4) and bilateral (n = 5) cleft lip and palate patients and noncleft control subjects (n = 50). Using a video-based tracking system, three-dimensional displacement of 14 well-defined nasolabial landmarks was measured during four set facial animations without controlling for head motion. The modified Procrustes fit method eliminated the contributions of head motion by matching the most stable landmarks of each video-recorded frame of the face during function to frames at rest. Its effectiveness was found to approximate that of a previous method (i.e., use of a maxillary occlusal splint to which stable dentition-based markers were attached). Data from both the unilateral and bilateral cleft lip and palate patients fell outside the normal range of maximum displacements and of asymmetry, and individual patients demonstrated greater right-versus-left asymmetry in maximum displacement than did individual noncleft subjects. It is concluded that the modified Procrustes fit method is fast, is easy to apply, and allows subjects to move the head naturally without the inconvenience of a splint while facial movement data are being collected. Results obtained using this method support the view that facial movements in cleft patients may be severely hampered and that assessment of facial animation should be strongly considered when contemplating surgical lip revisions.

Stature, age, and gender effects on reach motion postures.

The rapid adoption of software to simulate human reach motions in the design of vehicle interiors and manufacturing and office workstations has required a sophisticated understanding of human motions. This paper describes how more than 3,000 right-arm reaching motions of a diverse group of participants were captured and statistically modeled. The results demonstrate that stature and age have a larger effect than does gender on reach motion postures for motions chosen by the participants while reaching to targets placed throughout a typical automobile interior. We propose that these methods, models, and results can assist the further development of human motion simulation software for ergonomic purposes, such as for the design or evaluation of vehicle interiors or industrial workplaces, to ensure that various population groups are physically accommodated.

Rectifying postures reconstructed from joint angles to meet constraints.

Postures are often described and modeled using angles between body segments rather than joint coordinates. Models can be used to predict these angles as a function of anthropometry and postural requirements. Postural representation, however, requires the joint coordinates. The use of conventional forward kinematics to derive joint coordinates from predicted angles may violate task constraints, such as the placement of a hand on a target or a foot on a pedal. Errors arise because the anthropometry or other motion characteristics of a subject, for which the prediction is to be made, may differ from the data from which the prediction model was derived. We describe how to rectify model-predicted postures to exactly satisfy such task constraints. We require that the model used for predicting the angles also produce estimates of the variation in these predictions. We show how to alter the initial angle predictions, with the amount of perturbation at each angle dependent on the accuracy of its estimation, so as to exactly satisfy the joint coordinate constraints. Finally, we show in an empirical example that this correction usually produces better overall predictions of posture than those obtained initially.

Sensitivity of a method for the analysis of facial mobility. I. Vector of displacement.

OBJECTIVE: (1) To determine which facial landmarks show the greatest movement during specific facial animations and (2) to determine the sensitivity of our instrument in using these landmarks to detect putatively abnormal facial movements. DESIGN: Movements of an array of skin-based landmarks on five healthy human subjects (2 men and 3 women; mean age, 27.6 years; range, 26 to 29 years) were observed during the execution of specific facial animations. To investigate the instrument sensitivity, we analyzed facial movements during maximal smile animations in six patients with different types of functional problems. In parallel, a panel was asked to view video recordings of the patients and to rate the degree of motor impairment. Comparisons were made between the panel scores and those of the measurement instrument. RESULTS: Specific regions of the face display movement that is representative of specific animations. During the smile animation, landmarks on the mid- and lower facial regions demonstrated the greatest movement. A similar pattern of movement was seen during the cheek puff animation, except that the infraorbital and chin regions demonstrated minimal movement. For the grimace and eye closure animations, the upper, mid-facial, and upper-lip regions exhibited the greatest movement. During eye opening, the upper and mid-facial regions, excluding the upper lip and cheek, moved the most, and during lip purse, markers on the mid- and lower face demonstrated the most movement. We used the smile-sensitive landmarks to evaluate individuals with functional impairment and found good agreement between instrument rankings based on the data from these landmarks and the panel rankings. CONCLUSION: The present method of three-dimensional tracking has the potential to detect and characterize a range of clinically significant functional deficits.

Sensitivity of a method for the analysis of facial mobility. II. Interlandmark separation.

OBJECTIVE: This study demonstrates a method of quantifying facial movements based on distortions of the skin surface. DESIGN: Landmarks were identified on the faces of five healthy human subjects (2 men and 3 women; mean age, 27.6 years; range, 26 to 29 years), and the distortions were characterized by changes in the separation between 20 pairs of landmark distances during specific maximal facial animations: smile, lip purse, cheek puff, grimace, eye closure, and eye opening. Data were recorded with a video-based tracking system for a period of 3 seconds at a sampling rate of 60 Hz or frames per second. For each subject, we analyzed the change in the separation of 20 pairs of landmarks, of which the majority were bilaterally symmetrical and functionally active. RESULTS: Characteristic patterns of movement emerged for each animation. We found that smiling involved movements of the lateral orbital, circumoral, and chin regions; grimacing involved the inner orbital, lateral orbital, lateral nasal, and upper-lip regions; eye closure involved the inner orbital, lateral orbital, and, to a lesser degree, lateral nasal regions; eye opening involved the inner and lateral orbital regions; cheek puffing involved the cheek and lower-lip regions; and the lip purse animation involved the nasolabial, cheek, commissure, and lip regions. CONCLUSION: This measurement of distortion provided a quantitative estimate of facial movement, and this approach is especially applicable to patients with unilateral problems in which the patient can serve as his or her own control.

Distribution of the admixture test for the detection of linkage under heterogeneity.

The admixture test for the detection of linkage under heterogeneity is considered. We show that the null distribution of this test statistic has half its weight concentrated on zero and the other half on a complicated distribution that can be approximated by max (X1,X2) where X1 and X2 are independent X1(2) variables. We also investigate the stability of the size of the test for small samples. The power of this test to detect linkage, when heterogeneity is present, can be substantially greater than the standard test that assumes homogeneity. Even when heterogeneity is not present, the test is only slightly less powerful than the homogeneous test. This would suggest the use of the admixture test in preference to the homogeneous test if the presence of heterogeneity is at all suspected.

Improved sib-pair linkage test for disease susceptibility loci.

An improved sib-pair test for linkage is introduced which is superior to the previously proposed tests. The test is derived from the standard chi-squared goodness of fit statistic by restricting the alternative hypothesis to the genetically possible. Critical values are given and exact power comparisons are made with the previously proposed tests. The new test is shown to be more powerful for finite samples as well as being asymptotically uniformly most powerful.