High-precision handling processes are essential for various high-tech industries and are typically realized using specialized high precision robots. Articulated robots are rarely used for such tasks ...due to their low stiffness and accuracy stemming from their kinematic structure. This work presents a methodology for designing handling processes that maximise repeatability with articulated robots. By considering their kinematic structures’ highly pose dependent properties as well as sensitivity to external disturbances in every step of the processes design, significantly improved repeatability can be achieved. The applicability of the new methodology is verified experimentally using the example of handling of large silicon dies.
Purpose
The purpose was to evaluate the repeatability of a new swept-source optical biometer for measuring ocular biometric parameters.
Methods
Thirty subjects with healthy and phakic eyes were ...included in this study, and only one eye per participant was analysed. Each eye was measured five times with the IOLMaster 700 swept-source optical biometer (Carl Zeiss Meditec, Jena, Germany). Axial length (AL), anterior chamber depth (ACD), central corneal thickness (CCT), lens thickness (LT), white-to-white (WTW), and K1 and K2 keratometric readings were evaluated. The repeatability of swept-source biometry was evaluated on the basis of five measurements captured for each patient.
Results
The repeatability limits for the axial measurements AL, ACD, CCT, and LT were 0.03, 0.07, 0.004, and 0.11 mm, respectively. For the WTW distance and both keratometry readings, the repeatability limits were 0.20, 0.06, and 0.05 mm, respectively. The AL resulted in the lowest coefficient of variation, and the LT had the highest one. The spherical equivalent showed statistically significant negative correlations with the AL and ACD.
Conclusion
Swept-source optical biometry showed high repeatability performance for all biometric parameters in healthy eyes, where the correlation between the spherical equivalent and AL showed the strongest value.
Cardiac-related mortality is increasing in farmed salmon. Non-invasive tools for examining and screening for cardiac morphology and function are limited, and most common methodologies are lethal, ...time-consuming, and immobile. Echocardiography has previously been tested as a non-invasive, quick, and portable alternative, though its implementation is minimal. Improvements in echocardiographic techniques during the last decade have enabled more refined assessments of structure and function and hold potential for use in fish farms. Utilising a compact, transportable ultrasound system, we examined the applicability of echocardiography in Atlantic salmon (Salmo salar L.). Several protocols and projections were tested, and intra- and inter-variation for both operators (image acquisition) and observers (image analysis) were assessed. In addition, the accuracy of cardiac structure/function measurements was compared with standard methods. In general, high accuracy and reproducibility of cardiac dimensions and functional parameters were found within the same and between different observers analysing the same dataset (intra- and inter-observer). Measurements between recordings of the same operator (intra-operator) and between different operators (inter-operator) were less accurate and repeatable but comparable to observations in previous human and mammalian studies. Cardiac output was slightly higher when measured with echocardiography compared to transit time flow probe. Yet, a strong correlation exists between the two methods. Furthermore, morphology measured in excised hearts ex vivo was comparable to echocardiography measurements and strongly correlated. Thus, ultrasound presents a highly feasible, non-invasive, and swift alternative to current methods for detailed cardiac assessment of salmon hearts.
•Echocardiography is a non-invasive option for cardiac analysis in Atlantic salmon.•Intra- and inter-variability is comparable to human and mammalian studies.•Echocardiography yields measurements similar to invasive methods.
1. Repeatability represents a key parameter in ecological and evolutionary research. Repeatability is underpinned by developmental plasticity and genetic variation but may become biased upwards by ...repeatable differences in environments to which individuals respond plastically. The extent of upward bias caused by the latter mechanism (causing "pseudo-repeatability") is important yet rarely investigated in ecological research. 2. We repeatedly assayed a key behaviour (flight initiation distance) affecting longevity in a wild cricket population (Gryllus campestris). We used naturally moving, translocated and forced-stationary individuals to study bias in repeatability caused by spatial variability in environmental conditions. 3. Our experiments acknowledged that translocations might themselves bias repeatability estimates if animals respond to handling procedures (a necessary component of translocations). Individuals were, therefore, either (i) repeatedly translocated and assayed or (ii) assayed at multiple burrows as part of natural movements. This enabled estimation of behavioural variance attributable to individual, burrow and residual components within each treatment; comparison across treatments addressed whether translocations caused bias. We also calculated repeatability for individuals that were forced to be stationary to investigate whether this led to upward bias of repeatability. 4. For adult crickets, individual explained 17.8% versus 17.2%, and burrow 8.7% versus 10.3%, of the behavioural variance in translocated versus natural-movement treatments. Repeatability for forced-stationary adults was 31.1%, thereby demonstrating experimentally that certain study designs bias repeatability upwards. For translocated juveniles, individual explained 10.0% and burrow 6.0% of the variance, while in the natural-movement treatment, those components could not be separated as juveniles do not switch burrows. Translocations did not lead to detectable biases in behavioural mean or variance. 5. Repeatability was not biased for adults subjected to the natural-movement treatment because individuals were assayed under many different environments, facilitating the separation of individual from burrow effects. Upward bias would have occurred with less optimal sampling schemes: if individuals had been assayed repeatedly at the same burrow. We, therefore, recommend that translocation experiments are more commonly applied, particularly in stationary species, to ensure the unbiased estimation of repeatability.
Growing evidence suggests that individual variation in learning is ubiquitous, but why this is the case and what the consequences are is still a subject of much debate and research. One key set of ...explanations for variation in learning behaviour is that it relates to variation in animal personality traits. If personality traits affect how an individual interacts with its environment or processes information, this could directly affect performance in learning tasks. While this idea is generally well supported, there are inconsistent results on the relationships between specific personality traits and performance on different learning tasks, highlighting the need to measure multiple personality traits and to quantify different aspects of learning in the same individuals. We examined the relationship between three putative personality traits – aggression, latency to emerge from a shelter and time to contact a novel object – and learning speed in both initial and reversal olfactory learning in the house cricket, Acheta domesticus. Crickets were assayed for each personality trait, then tested for their speed to associate an odour with a water reward. Both aggression and latency to emerge were significantly repeatable, but only latency to emerge was related to learning speed, with individuals that took longer to emerge from the shelter requiring fewer trials to reach the learning criterion for both the initial and reversal learning experiments. We also identified sex differences in learning speed in the different experiments. Thus, our results provide some support for a relationship between personality and learning in an invertebrate.
•Individuals vary in learning ability, and personality may explain why this is.•Aggression and latency to emerge were repeatable personality traits in crickets.•Crickets successfully learned and reversal learned an olfactory association.•Learning speed was associated with latency to emerge.•Personality affects individual variation in learning speed in crickets.
To develop 3D T1ρ and T2 imaging based on the same sequence structure on MR systems from multiple vendors, and to evaluate intra-site repeatability and inter-site inter-vendor reproducibility of T1ρ ...and T2 measurements of knee cartilage.
3D magnetization-prepared angle-modulated partitioned k-space spoiled gradient echo snapshots (3D MAPSS) were implemented on MR systems from Siemens, GE and Philips. Phantom and human subject data were collected at four sites using 3T MR systems from the three vendors with harmonized protocols. Phantom data were collected by means of different positioning of the coil. Volunteers were scanned and rescanned after repositioning. Two traveling volunteers were scanned at all sites. Data were transferred to one site for centralized processing.
Intra-site average coefficient of variations (CVs) ranged from 1.09% to 3.05% for T1ρ and 1.78–3.30% for T2 in phantoms, and 1.60–3.93% for T1ρ and 1.44–4.08% for T2 in volunteers. Inter-site average CVs were 5.23% and 6.45% for MAPSS T1ρ and T2, respectively in phantoms, and 8.14% and 10.06% for MAPSS T1ρ and T2, respectively, In volunteers.
This study showed promising results of multi-site, multi-vendor reproducibility of T1ρ and T2 values in knee cartilage. These quantitative measures may be applied in large-scale multi-site, multi-vendor trials with controlled sequence structure and scan parameters and centralized data processing.
Many interest point detectors have been designed so far to work in two dimensional (2-D) images. However, expansion of these detectors into the third dimension for three dimensional (3-D) images can ...refine their representational power. This paper presents how the Harris corner, LoG filtering-based blob, and salient regions detectors can be expanded to find interest points in volumetric images handling multiple slices collectively. Performances of 2-D and 3-D detector implementations were assessed both qualitatively and quantitatively with value combinations of different parameters using metrics such as F1-score, localization error, and repeatability in binary images of twenty 3-D object models from the Princeton Shape Benchmark (PSB). Computation of F1-score and localization error depended on some manually marked ground truth points, while repeatability measurement was according to the proximity of the detected point sets. The 3-D detectors were evaluated as more successful in capturing distinctive and sparse interest points on 3-D object surfaces in qualitative analyses. Despite having greater computational complexities, most of the 3-D detectors yielded better average F1-score, localization accuracy, and repeatability given uniqueness constraint on the matched points in quantitative analyses. Therefore, the 3-D detectors appear preferable when longer working durations or sparser representations would not constitute any disadvantage.
Udder conformation is directly related to milk yield, cow health, workability, and welfare. Automatic milking systems (AMS, also known as milking robots) have become popular worldwide, and the number ...of dairy farms adopting these systems have increased considerably over the past years. In each milking visit, AMS record the location of the 4 teats as Cartesian coordinates in a xyz plan, which can then be used to derive udder conformation traits. AMS generate a large amount of per milking visit data for individual cows, which contribute to an accurate assessment of important traits such as udder conformation without the addition of human classifier errors (in subjective scoring systems). Therefore, the primary objectives of this study were to estimate genomic-based genetic parameters for udder conformation traits derived from AMS records in North American Holstein cattle and to assess the genetic correlation between the derived traits for evaluating the feasibility of multi-trait genomic selection for breeding cows that are more suitable for milking in AMS. The Cartesian teat coordinates measured during each milking visit were collected by 36 milking robots in 4,480 Holstein cows from 2017 to 2021, resulting in 5,317,488 records. A total of 4,118 of these Holstein cows were also genotyped for 57,600 single nucleotide polymorphisms. Five udder conformation traits were derived: udder balance (UB, mm), udder depth (UD, mm), front teat distance (FTD, mm), rear teat distance (RTD, mm), and distance front-rear (DFR, mm). In addition, 2 traits directly related to cow productivity in the system were added to the study: daily milk yield (DY) and milk electroconductivity (EC; as an indicator of mastitis). Variance components and genetic parameters for UB, UD, FTD, RTD, DFR, DY, and EC were estimated based on repeatability animal models. The estimates of heritability (±standard error, SE) for UB, UD, FTD, RTD, DFR, DY, and EC were 0.41 ± 0.02, 0.79 ± 0.01, 0.53 ± 0.02, 0.40 ± 0.02, 0.65 ± 0.02, 0.20 ± 0.02, and 0.46 ± 0.02, respectively. The repeatability estimates (±SE) for UB, UD, FTD, RTD, and DFR were 0.82 ± 0.01, 0.93 ± 0.01, 0.87 ± 0.01, 0.83 ± 0.01, and 0.88 ± 0.01, respectively. The strongest genetic correlations were observed between the FTD and RTD (0.54 ± 0.03), UD and DFR (−0.47 ± 0.03), DFR and FTD (0.32 ± 0.03), and UD and FTD (−0.31 ± 0.03). These results suggest that udder conformation traits derived from Cartesian coordinates from AMS are moderately to highly heritable. Furthermore, the moderate genetic correlations between these traits should be considered when developing selection sub-indexes. The most relevant genetic correlations between traits related to cow milk productivity and udder conformation traits were between UD and EC (−0.25 ± 0.03) and between DFR and DY (0.30 ± 0.04), in which both genetic correlations are favorable. These findings will contribute to the design of genomic selection schemes for improving udder conformation in North American Holstein cattle, especially in precision dairy farms.
The coefficient of determination R2 quantifies the proportion of variance explained by a statistical model and is an important summary statistic of biological interest. However, estimating R2 for ...generalized linear mixed models (GLMMs) remains challenging. We have previously introduced a version of R2 that we called for Poisson and binomial GLMMs, but not for other distributional families. Similarly, we earlier discussed how to estimate intra-class correlation coefficients (ICCs) using Poisson and binomial GLMMs. In this paper, we generalize our methods to all other non-Gaussian distributions, in particular to negative binomial and gamma distributions that are commonly used for modelling biological data. While expanding our approach, we highlight two useful concepts for biologists, Jensen's inequality and the delta method, both of which help us in understanding the properties of GLMMs. Jensen's inequality has important implications for biologically meaningful interpretation of GLMMs, whereas the delta method allows a general derivation of variance associated with non-Gaussian distributions. We also discuss some special considerations for binomial GLMMs with binary or proportion data. We illustrate the implementation of our extension by worked examples from the field of ecology and evolution in the R environment. However, our method can be used across disciplines and regardless of statistical environments.
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