Comparison of force variables and dynamic strength index between age groups in elite young Brazilian football goalkeepers.

Introduction: The application of muscle force is a determinant of football success as it is inherent to the motor control and sport. The aims of this study are: (1) to describe force variables Isometric Maximal Force (IMF), Concentric Peak Force (CPPF), and Dynamic Strength Index (DSI) in football goalkeepers from different age groups; (2) to compare these variables' behavior between those groups. Methods: The sample was formed by 19 youth players (15.97 ± 1.55 years old) from a first-division Brazilian football team. The CPPF and IMF variables were obtained through the Countermovement jump and isometric squat tests, respectively. For data collection, a force plate (Cefise, Brazil) was used with an acquisition frequency of 600 Hz and mono-axial. The DSI was calculated using the ratio between CPPF and IMF. For data analysis, the sample was separated into clusters by age. After the grouping, a descriptive analysis of the data and a comparison between the groups with p < 0.05. Results: The sample was grouped into three groups (GA, GB, and GC) and one of the individuals did not enter the group, totaling 18 individuals in the analyzed sample. The comparison between the ages of the groups showed a significant difference and small and moderate effect size (ES), validating the cluster strategy. The CPPF and IMF variables showed increased values according to chronological age. CPPF showed a significant difference between GA-GB, (ES = very large) GA-GC (ES = very large), and GB-GC (ES = moderate). The IMF variable had significant differences between GA-GB (ES = moderate) and GA-GC (ES = very large). However, DSI showed significant differences only between GA GB (ES = small) and GB-GC (ES = very large). Conclusions: The CPPF and IMF variables had constant increases and distinct values with an increase according to age, and this did not occur for DSI. The difference between CPPF and IMF compared to DSI bring to light the variability in dynamics and proportionality between muscular force in the concentric phase and maximal force in the isometric regime during the developmental process over chronological age in soccer goalkeepers.

Qualitative analysis of the most locally relevant runoff and erosion parameters for constructing Brazilian scenarios.

Estimating exposure is one of the most important steps in an environmental risk analysis of crop-protection products to nontarget organisms. Regulatory agencies such as the US Environmental Protection Agency (USEPA), Pest Management Regulatory Agency (PMRA), and European Food Safety Authority (EFSA) all use mathematical exposure models in their regulatory assessment process. Brazil has been discussing the adoption of the Pesticide in Water Calculator (PWC) to be applied in aquatic pesticide risk assessment. Therefore, a qualitative sensitivity analysis (Morris OAT method) was performed to understand which are the most important local parameters in the PWC to estimate environmental concentrations in surface water (EECSW ). In addition, an exercise made up of two corn scenarios in two Brazilian regions was developed (Uberlândia [UDI] and Arapoti [ARA]). Two herbicides with different soil-binding properties and modes of action were selected to estimate the EECSW . The results demonstrated that the parameters of importance were different for each site, probably the result of different soil characteristics and meteorological patterns. This outcome suggests that regulatory agencies should consider developing more than one scenario to account for different agricultural regions. For Herbicide 1, the EECSW for UDI were similar to US scenarios, whereas for ARA they were lower. For Herbicide 2, the EECSW for the UDI site was higher than most of the US scenarios, whereas at the ARA site, EECs were similar to four US scenarios and lower than the other six. Local data were used as a refinement, resulting in the decrease in the EECSW for both herbicides in the UDI site. For the ARA site, Herbicide 1 displayed a similar EECSW value, whereas for Herbicide 2, it was lower after the refinement. Overall, these results demonstrated the importance of developing local scenarios to provide more realism to estimate pesticide exposure from its agricultural use and may help regulators to determine and recommend mitigations regarding the use of crop-protection products. Integr Environ Assess Manag 2023;19:1374-1384. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Are standard aquatic test species and methods adequate surrogates for use in environmental risk assessment of pesticides in tropical environments?

In regulatory risk assessment, surrogate species of fish, aquatic invertebrates, and primary producers are tested to assess toxicity and subsequently the risk of pesticides to freshwater biota. This study evaluates whether the standard, surrogate test species (mostly temperate in latitudinal distribution) used in many parts of the world are suitable surrogates for first-tier risk assessments involving tropical freshwater biota. Data for the toxicity of pesticides to tropical fish, invertebrates, and primary producer species were extracted from the USEPA ECOTOX database and peer-reviewed literature. For each pesticide, the most sensitive regulatory endpoint extracted from the US Environmental Protection Agency (USEPA) and European Food Safety Authority (EFSA) dossiers for freshwater fish, invertebrates, and primary producers was selected. The ratios of the endpoint for tropical species and for the most sensitive regulatory endpoint for the appropriate taxonomic group were determined. A value >1 indicates that the tropical species is less sensitive than the respective standard regulatory species. Tropical fish species were less sensitive than standard fish species in 84% of the comparisons, and in 93.5% of the comparisons, tropical fish were less or similarly sensitive (within a factor of 5). For aquatic invertebrates, 78.1% of the evaluated tropical species were less sensitive than standard species and 93.3% of tropical invertebrates species were less or similarly sensitive. For primary producers, 96% of tropical species were less sensitive than standard test species. Overall, standard species used globally were more sensitive or similarly sensitive compared to tropical species in more than 93% of the cases. In conclusion, the data show that freshwater toxicity data for pesticides from tests using standard test species, tested according to international accepted guidelines, are appropriate for use in first-tier risk assessments for tropical environments. Integr Environ Assess Manag 2023;19:202-212. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Pseudoreplication and the usage of biomarkers in ecotoxicological bioassays.

Pseudoreplication is a widely discussed topic in the scientific community. Its principal critique concerns the lack of independence in flawed experimental designs and the use of inferential statistics to test the hypothesis of such experiments. Thirty years after its appearance, it remains misunderstood by many researchers, including ecotoxicologists. In the present study, we try to clarify some of its concepts by filling in what seems to be a gap in the terminology of manipulative experiments. We propose the term "experimental medium" to refer strictly to the relevant spatial scale of the experiment to preserve the specificity of the experimental and observational units and to display pseudoreplication as a kind of misinterpretation and/or misanalysis of inferential statistics. A classification of the types of experimental designs in ecotoxicology is offered, and the problems in using inferential statistics in suboptimal designs are discussed. We hope to shed some light on such a classic topic for ecotoxicologists. Environ Toxicol Chem 2017;36:2868-2874. © 2017 SETAC.

Investigation of potential artefactual changes in measurements of impedance changes during evoked activity: implications to electrical impedance tomography of brain function.

Electrical impedance tomography (EIT) could provide images of fast neural activity in the adult human brain with a resolution of 1 ms and 1 mm by imaging impedance changes which occur as ion channels open during neuronal depolarization. The largest changes occur at dc and decrease rapidly over 100 Hz. Evoked potentials occur in this bandwidth and may cause artefactual apparent impedance changes if altered by the impedance measuring current. These were characterized during the compound action potential in the walking leg nerves of Cancer pagurus, placed on Ag/AgCl hook electrodes, to identify how to avoid artefactual changes during brain EIT. Artefact-free impedance changes (δZ) decreased with frequency from -0.045 ± 0.01% at 225 Hz to -0.02 ± 0.01% at 1025 Hz (mean ± 1 SD, n = 24 in 12 nerves) which matched changes predicted by a finite element model. Artefactual δZ reached c.300% and 50% of the genuine membrane impedance change at 225 Hz and 600 Hz respectively but decreased with frequency of the applied current and was negligible above 1 kHz. The proportional amplitude (δZ (%)) of the artefact did not vary significantly with the amplitude of injected current of 5-20 µA pp. but decreased significantly from -0.09 ± 0.024 to -0.03 ± 0.023% with phase of 0 to 45°. For fast neural EIT of evoked activity in the brain, artefacts may arise with applied current of >10 µA. Independence of δZ with respect to phase but not the amplitude of applied current controls for them; they can be minimized by randomizing the phase of the applied measuring current and excluded by recording at >1 kHz.

Differential reward coding in the subdivisions of the primate caudate during an oculomotor task.

The basal ganglia play a pivotal role in reward-oriented behavior. The striatum, an input channel of the basal ganglia, is composed of subdivisions that are topographically connected with different cortical and subcortical areas. To test whether reward information is differentially processed in the different parts of the striatum, we compared reward-related neuronal activity along the dorsolateral-ventromedial axis in the caudate nucleus of monkeys performing an asymmetrically rewarded oculomotor task. In a given block, a target in one position was associated with a large reward, whereas the other target was associated with a small reward. The target position-reward value contingency was switched between blocks. We found the following: (1) activity that reflected the block-wise reward contingency emerged before the appearance of a visual target, and it was more prevalent in the dorsal, rather than central and ventral, caudate; (2) activity that was positively related to the reward size of the current trial was evident, especially after reward delivery, and it was more prevalent in the ventral and central, rather than dorsal, caudate; and (3) activity that was modulated by the memory of the outcomes of the previous trials was evident in the dorsal and central caudate. This multiple reward information, together with the target-direction information, was represented primarily by individual caudate neurons, and the different reward information was represented in caudate subpopulations with distinct electrophysiological properties, e.g., baseline firing and spike width. These results suggest parallel processing of different reward information by the basal ganglia subdivisions defined by extrinsic connections and intrinsic properties.

Encoding of social state information by neuronal activities in the macaque caudate nucleus.

Social animals adjust their behavior according to social relationships and momentary circumstances. Dominant-submissive relationships modulate, but do not completely determine, their competitive behaviors. For example, a submissive monkey's decision to retrieve food depends not only on the presence of dominant partners but also on their observed behavior. Thus, behavioral expression requires a dynamic evaluation of reward outcome and momentary social states. The neural mechanisms underlying this evaluation remain elusive. The caudate nucleus (CN) plays a pivotal role in representing reward expectation and translating it into action selection. To investigate whether their activities encode social state information, we recorded from CN neurons in monkeys while they performed a competitive food-grab task against a dominant competitor. We found two groups of CN neurons: one primarily responded to reward outcome, while the other primarily tracked the monkey's social state. These social state-dependent neurons showed greater activity when the monkeys freely retrieved food without active challenges from the competitor and reduced activity when the monkeys were in a submissive state due to the competitor's active behavior. These results indicate that different neuronal activities in the CN encode social state information and reward-related information, which may contribute to adjusting competitive behavior in dynamic social contexts.

Higher-order interactions characterized in cortical activity.

In the cortex, the interactions among neurons give rise to transient coherent activity patterns that underlie perception, cognition, and action. Recently, it was actively debated whether the most basic interactions, i.e., the pairwise correlations between neurons or groups of neurons, suffice to explain those observed activity patterns. So far, the evidence reported is controversial. Importantly, the overall organization of neuronal interactions and the mechanisms underlying their generation, especially those of high-order interactions, have remained elusive. Here we show that higher-order interactions are required to properly account for cortical dynamics such as ongoing neuronal avalanches in the alert monkey and evoked visual responses in the anesthetized cat. A Gaussian interaction model that utilizes the observed pairwise correlations and event rates and that applies intrinsic thresholding identifies those higher-order interactions correctly, both in cortical local field potentials and spiking activities. This allows for accurate prediction of large neuronal population activities as required, e.g., in brain-machine interface paradigms. Our results demonstrate that higher-order interactions are inherent properties of cortical dynamics and suggest a simple solution to overcome the apparent formidable complexity previously thought to be intrinsic to those interactions.

Hierarchical interaction structure of neural activities in cortical slice cultures.

Recent advances in the analysis of neuronal activities suggest that the instantaneous activity patterns can be mostly explained by considering only first-order and pairwise interactions between recorded elements, i.e., action potentials or local field potentials (LFP), and do not require higher-than-pairwise-order interactions. If generally applicable, this pairwise approach greatly simplifies the description of network interactions. However, an important question remains: are the recorded elements the units of interaction that best describe neuronal activity patterns? To explore this, we recorded spontaneous LFP peak activities in cortical organotypic cultures using planar, integrated 60-microelectrode arrays. We compared predictions obtained using a pairwise approach with those using a hierarchical approach that uses two different spatial units for describing the activity interactions: single electrodes and electrode clusters. In this hierarchical model, short-range interactions within each cluster were modeled by pairwise interactions of electrode activities and long-range interactions were modeled by pairwise interactions of cluster activities. Despite the relatively low number of parameters used, the hierarchical model provided a more accurate description of the activity patterns than the pairwise model when applied to ensembles of 10 electrodes. Furthermore, the hierarchical model was successfully applied to a larger-scale data of approximately 60 electrodes. Electrode activities within clusters were highly correlated and spatially contiguous. In contrast, long-range interactions were diffuse, suggesting the presence of higher-than-pairwise-order interactions involved in the LFP peak activities. Thus, the identification of appropriate units of interaction may allow for the successful characterization of neuronal activities in large-scale networks.

A greedy algorithm for supervised discretization.

We present a greedy algorithm for supervised discretization using a metric defined on the space of partitions of a set of objects. This proposed technique is useful for preparing the data for classifiers that require nominal attributes. Experimental work on decision trees and naïve Bayes classifiers confirm the efficacy of the proposed algorithm.

Deciphering gene expression profiles generated from DNA microarrays and their applications in oral medicine.

Genome-wide monitoring of gene expression profiles using DNA microarrays provides a unique approach to exploring the biological processes underlying oral diseases and disorders by providing a comprehensive survey of a cell's or tissue's transcriptional mapping. This revolutionary technology allows for the simultaneous assessment of the transcription levels of tens of thousands of genes, and of their relative expression between normal and diseased cells. As microarray data analysis evolves, there is a widespread hope that microarrays will significantly impact our ability to explore the genetic changes associated with disease etiology and development, ultimately leading to the discovery of new biomarkers for disease diagnosis and prognosis prediction as well as new therapeutic tools. The goal of this manuscript is to review 2 of the most commonly used microarray technologies, provide an overview of data analyses involved in a typical microarray experiment, and comment upon the application of microarrays to oral medicine.