Nanoplastics and biota behaviour: known effects, environmental relevance, and research needs

Behaviour is increasingly recognized as a sensitive screening tool to detect the effects of environmental disturbances on biota, resulting from molecular, biochemical, and physiological processes. In this sense, several (eco)toxicological studies have been assessing and reporting the behavioural effects of xenobiotics, even at very low doses. Different behavioural endpoints may help to estimate more accurately the impact of nanoplastics (NPLs) in fitness-related behaviours and, therefore, should be included in environmentally relevant exposure scenarios. This paper presents a critical review of current scientific knowledge regarding tested behavioural endpoints on freshwater organisms exposed to NPLs, findings’ environmental relevance and research needs. Overall, the limited number of studies addressed only 3 types of polymers, with spherical polystyrene (PS) being the most studied, but all identified behaviour as a sensitive endpoint to NPLs exposure, with potential effects on populations. However, applied methodologies differ making comparison of effects between different sizes or polymers difficult.publishe

Noise-robust method for image segmentation

Segmentation of noisy images is one of the most challenging problems in image analysis and any improvement of segmentation methods can highly influence the performance of many image processing applications. In automated image segmentation, the fuzzy c-means (FCM) clustering has been widely used because of its ability to model uncertainty within the data, applicability to multi-modal data and fairly robust behaviour. However, the standard FCM algorithm does not consider any information about the spatial linage context and is highly sensitive to noise and other imaging artefacts. Considering above mentioned problems, we developed a new FCM-based approach for the noise-robust fuzzy clustering and we present it in this paper. In this new iterative algorithm we incorporated both spatial and feature space information into the similarity measure and the membership function. We considered that spatial information depends on the relative location and features of the neighbouring pixels. The performance of the proposed algorithm is tested on synthetic image with different noise levels and real images. Experimental quantitative and qualitative segmentation results show that our method efficiently preserves the homogeneity of the regions and is more robust to noise than other FCM-based methods

The holographic superconductors in higher-dimensional AdS soliton

We explore the behaviors of the holographic superconductors at zero temperature for a charged scalar field coupled to a Maxwell field in higher-dimensional AdS soliton spacetime via analytical way. In the probe limit, we obtain the critical chemical potentials increase linearly as a total dimension $d$ grows up. We find that the critical exponent for condensation operator is obtained as 1/2 independently of $d$, and the charge density is linearly related to the chemical potential near the critical point. Furthermore, we consider a slightly generalized setup the Einstein-Power-Maxwell field theory, and find that the critical exponent for condensation operator is given as $1/(4-2n)$ in terms of a power parameter $n$ of the Power-Maxwell field, and the charge density is proportional to the chemical potential to the power of $1/(2-n)$.Comment: LaTeX, 16 pages, 5 figures, typos corrected, one reference added, version to appear in European Physical Journal

Are early and young life stages of fish affected by paroxetine? A case study with Danio rerio

Paroxetine (PAR) is a selective serotonin reuptake inhibitor (SSRI) antidepressant increasingly detected in surface waters worldwide. Its environmental presence raises concerns about the potential detrimental effects on non-target organisms. Thus, this study aimed to increase knowledge on PAR's potential environmental impacts, assessing the effects of commercial formulation (PAR-c) and active ingredient (PAR-a) on fish. Therefore, the short-term exposure effects of PAR-c and PAR-a were assessed on zebrafish (Danio rerio) embryos/larvae to determine the most toxic formulation [through median lethal (LC50) and effective concentrations (EC50)]. PAR-c and PAR-a induced morphological abnormalities (scoliosis) in a dose-dependent manner from 96 hours post-fertilization onwards, suggesting the involvement of a fully functional biotransformation system. As PAR-c exhibited higher toxicity, it was selected to be tested in the subsequent stage (juvenile stage), which was more sensitive (lower LC50). PAR-c significantly decreased fish swimming activity and disrupted fish stress response. Overall, the results highlight the ability of PAR-c to adversely affect fish swimming performance, an effect that persisted even after exposure ceases (21-day depuration), suggesting that PAR-c may impair individual fitness

Identifying knowledge gaps in understanding the effects of selective serotonin reuptake inhibitors (SSRIs) on fish behaviour

Selective serotonin reuptake inhibitors (SSRIs) are a class of antidepressants increasingly prescribed to treat patients with clinical depression. As a result of the significant negative impact of the COVID-19 pandemic on the population's mental health, its consumption is expected to increase even more. The high consumption of these substances leads to their environmental dissemination, with evidence of their ability to compromise molecular, biochemical, physiological, and behavioural endpoints in non-target organisms. This study aimed to provide a critical review of the current knowledge regarding the effects of SSRI antidepressants on fish ecologically relevant behaviours and personality-dependent traits. A literature review shows limited data concerning the impact of fish personality on their responses to contaminants and how such responses could be influenced by SSRIs. This lack of information may be attributable to a lack of widely adopted standardized protocols for evaluating behavioural responses in fish. The existing studies examining the effects of SSRIs across various biological levels overlook the intra-specific variations in behaviour and physiology associated with different personality patterns or coping styles. Consequently, some effects may remain undetected, such as variations in coping styles and the capacity to handle environmental stressors. This oversight could potentially result in long-term effects with ecological implications. Data support the need for more studies to understand the impact of SSRIs on personality-dependent traits and how they may impair fitness-related behaviours. Given the considerable cross-species similarity in the personality dimensions, the collected data may allow new insights into the correlation between personality and animal fitness

Pareto Law in a Kinetic Model of Market with Random Saving Propensity

We have numerically simulated the ideal-gas models of trading markets, where each agent is identified with a gas molecule and each trading as an elastic or money-conserving two-body collision. Unlike in the ideal gas, we introduce (quenched) saving propensity of the agents, distributed widely between the agents ($0 \le \lambda < 1$). The system remarkably self-organizes to a critical Pareto distribution of money $P(m) \sim m^{-(\nu + 1)}$ with $\nu \simeq 1$. We analyse the robustness (universality) of the distribution in the model. We also argue that although the fractional saving ingredient is a bit unnatural one in the context of gas models, our model is the simplest so far, showing self-organized criticality, and combines two century-old distributions: Gibbs (1901) and Pareto (1897) distributions.Comment: 5 pages RevTeX4, 6 eps figures, to be published in Physica A (2004

Childrens’ personality traits scale and peer acceptance

 O presente estudo objetivou verificar se a aceitação entre pares está relacionada a traços de personalidade. Foram estudados 411 alunos do ensino fundamental de uma escola pública, por meio da Escala de Traços de Personalidade para Crianças e o Teste Sociométrico. Dos resultados das análises de correlação e discriminação de grupos extremos ressaltaram, principalmente, três informações. Uma delas foi que as meninas tiveram uma pontuação média mais baixa em neuroticismo, mas sua presença produziu aceitação na escolha entre pares, enquanto que nos meninos, com média mais alta, não produziu esse efeito. A outra, que as meninas tiveram uma pontuação mais alta em psicoticismo e sociabilidade, não produzindo rejeição para as meninas, mas sim para os meninos. E, finalmente, as correlações foram baixas, apesar de significativas, tal como era esperado, pois a aceitação-rejeição deve ser apenas um dos componentes da personalidade. Nesse contexto, os dados desta pesquisa podem ser considerados evidência de validade para o Escala de Traços de Personalidade para Crianças. Palavras-chave: traços de personalidade; evidência de validade; teste sociométrico. The aim of this study was to identify whether personality traits and social acceptance are related. By means of the Escala de Traços de Personalidade para Crianças and Sociometric Test, 411 elementary public school students were studied. Among the results of correlation analysis and extreme group discrimination, three points of information were highlighted. The first point being that the neuroticism scores of girls were found to be lower than of boys, but its presence yielded to peer acceptance, whereas this reaction was not observed among the boys. The second point was that girls had higher scores for psychoticism and sociability than the boys, and this was related to the boys’ but not the girls’ peer rejection. The last point was that the correlations were low as expected, in spite of their significance; on this account, the peer acceptance-rejection factor must be take as just one of the personality components. In this context the data can be considered as valid evidence to Escala de Traços de Personalidade para Crianças. Keywords: personality traits; validity evidence; sociometric test