scholarly journals Action of Surfactants in Driving Ecotoxicity of Microplastic-Nano Metal Oxides Mixtures: A Case Study on Daphnia magna under Different Nutritional Conditions

2021 ◽  
Author(s):  
Cristiana Guerranti ◽  
Serena Anselmi ◽  
Francesca Provenza ◽  
Andrea Blašković ◽  
Monia Renzi

The series of experiments presented in the paper served to clarify the effects of contemporary exposure to surfactant, microplastics (polyethylene and polyvinyl chloride), and nanoparticles (TiO2 and ZnO) on the model organism Daphnia magna. Exposure was evaluated with respect to the age of the organisms (“young”, 24 hours old, and “aged” 10 days old specimens), trophic status (feeding or fasting), and the simultaneous presence of a surfactant. All the above-mentioned substances are present in the wastewater coming from various environmental sources from cosmetic products. The experiments were conducted in compliance with the OECD 202:2004 guideline, which is also a reference for ecotoxicity tests required by REACH. The results showed that surfactants enhance effects of toxicity produced by the exposure to the microplastic + nanoparticle mixtures. The influence due to factors such as nutrition (effect in fasting >> feeding conditions) and the age of individuals (effects in older >> younger animals) is essential. Concerning young individuals, exposure to PE-TiO2 is the most significant in terms of effects produced: it is very significant, especially in the presence of surfactant (both under fasting and feeding conditions). On the contrary, exposure to the PE-Zn mixture shows the minor effects. The comparison with the literature, especially as regards the possibility of interpreting the toxicity trends for the various mixtures with respect to the individual elements that compose them, leads to hypothesize additive effects still to be investigated and confirms the greatest toxicity contribution of TiO2.

Ecotoxicology ◽  
2019 ◽  
Vol 28 (8) ◽  
pp. 878-889 ◽  
Author(s):  
Monia Renzi ◽  
Andrea Blašković
Keyword(s):  

1997 ◽  
Vol 352 (1358) ◽  
pp. 1149-1154 ◽  
Author(s):  
Matteo Carandini ◽  
Horace B. Barlow ◽  
Lawrence P. O'keefe ◽  
Allen B. Poirson ◽  
J. Anthony Movshon

We tested the hypothesis that neurons in the primary visual cortex adapt selectively to contingencies in the attributes of visual stimuli. We recorded from single neurons in macaque V1 and measured the effects of adaptation either to the sum of two gratings (compound stimulus) or to the individual gratings. According to our hypothesis, there would be a component of adaptation that is specific to the compound stimulus. In a first series of experiments, the two gratings differed in orientation. One grating had optimal orientation and the other was orthogonal to it, and therefore did not activate the neuron under study. These experiments provided evidence in favour of our hypothesis. In most cells adaptation to the compound stimulus reduced responses to the compound stimulus more than it reduced responses to the optimal grating, and adaptation to the optimal grating reduced responses to the optimal grating more than it reduced responses to the compound stimulus. This suggests that a component of adaptation was specific to (and caused by) the simultaneous presence of the two orientations in the compound stimulus. To test whether V1 neurons could adapt to other contingencies in the stimulus attributes, we performed a second series of experiments, in which the component gratings were parallel but differed in spatial frequency, and were both effective in activating the neuron under study. These experiments failed to reveal convincing contingent effects of adaptation, suggesting that neurons cannot adapt equally well to all types of contingency.


1973 ◽  
Vol 38 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Linda Lynch ◽  
Annette Tobin

This paper presents the procedures developed and used in the individual treatment programs for a group of preschool, postrubella, hearing-impaired children. A case study illustrates the systematic fashion in which the clinician plans programs for each child on the basis of the child’s progress at any given time during the program. The clinician’s decisions are discussed relevant to (1) the choice of a mode(s) for the child and the teacher, (2) the basis for selecting specific target behaviors, (3) the progress of each program, and (4) the implications for future programming.


2015 ◽  
Vol 36-37 (1) ◽  
pp. 163-183
Author(s):  
Paul Taylor

John Rae, a Scottish antiquarian collector and spirit merchant, played a highly prominent role in the local natural history societies and exhibitions of nineteenth-century Aberdeen. While he modestly described his collection of archaeological lithics and other artefacts, principally drawn from Aberdeenshire but including some items from as far afield as the United States, as a mere ‘routh o’ auld nick-nackets' (abundance of old knick-knacks), a contemporary singled it out as ‘the best known in private hands' (Daily Free Press 4/5/91). After Rae's death, Glasgow Museums, National Museums Scotland, the University of Aberdeen Museum and the Pitt Rivers Museum in Oxford, as well as numerous individual private collectors, purchased items from the collection. Making use of historical and archive materials to explore the individual biography of Rae and his collection, this article examines how Rae's collecting and other antiquarian activities represent and mirror wider developments in both the ‘amateur’ antiquarianism carried out by Rae and his fellow collectors for reasons of self-improvement and moral education, and the ‘professional’ antiquarianism of the museums which purchased his artefacts. Considered in its wider nineteenth-century context, this is a representative case study of the early development of archaeology in the wider intellectual, scientific and social context of the era.


2015 ◽  
Vol 11 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Zsófia Demjén

This paper demonstrates how a range of linguistic methods can be harnessed in pursuit of a deeper understanding of the ‘lived experience’ of psychological disorders. It argues that such methods should be applied more in medical contexts, especially in medical humanities. Key extracts from The Unabridged Journals of Sylvia Plath are examined, as a case study of the experience of depression. Combinations of qualitative and quantitative linguistic methods, and inter- and intra-textual comparisons are used to consider distinctive patterns in the use of metaphor, personal pronouns and (the semantics of) verbs, as well as other relevant aspects of language. Qualitative techniques provide in-depth insights, while quantitative corpus methods make the analyses more robust and ensure the breadth necessary to gain insights into the individual experience. Depression emerges as a highly complex and sometimes potentially contradictory experience for Plath, involving both a sense of apathy and inner turmoil. It involves a sense of a split self, trapped in a state that one cannot overcome, and intense self-focus, a turning in on oneself and a view of the world that is both more negative and more polarized than the norm. It is argued that a linguistic approach is useful beyond this specific case.


Author(s):  
Raya Muttarak ◽  
Wiraporn Pothisiri

In this paper we investigate how well residents of the Andaman coast in Phang Nga province, Thailand, are prepared for earthquakes and tsunami. It is hypothesized that formal education can promote disaster preparedness because education enhances individual cognitive and learning skills, as well as access to information. A survey was conducted of 557 households in the areas that received tsunami warnings following the Indian Ocean earthquakes on 11 April 2012. Interviews were carried out during the period of numerous aftershocks, which put residents in the region on high alert. The respondents were asked what emergency preparedness measures they had taken following the 11 April earthquakes. Using the partial proportional odds model, the paper investigates determinants of personal disaster preparedness measured as the number of preparedness actions taken. Controlling for village effects, we find that formal education, measured at the individual, household, and community levels, has a positive relationship with taking preparedness measures. For the survey group without past disaster experience, the education level of household members is positively related to disaster preparedness. The findings also show that disaster related training is most effective for individuals with high educational attainment. Furthermore, living in a community with a higher proportion of women who have at least a secondary education increases the likelihood of disaster preparedness. In conclusion, we found that formal education can increase disaster preparedness and reduce vulnerability to natural hazards.


2006 ◽  
Vol 11 (1) ◽  
pp. 35-62
Author(s):  
Nawaz A. Hakro ◽  
Wadho Waqar Ahmed

This study is designed to assess the macroeconomic performance of fund-supported programs, and the sequencing and ordering of macroeconomic policies in the context of the Pakistan economy. The generalized evaluation estimator technique has been used to assess the macroeconomic impacts of the IMF supported programs. GDP growth, inflation rate, current account balance, fiscal balance and unemployment are used as the target variables in order to gauge economic performance during the program years. The vector of policy variables (that might have been adopted in the absence of programs) and the vector of foreign exogenous variables are also taken as explanatory variables in the model, so that the individual effect of the IMF supported programs could be assessed. The result suggests that as the IMF prescriptions were applied, the current account balance has worsened, the unemployment rate has significantly increased, and the inflation rate has increased during the years of fund-supported programs. Only the budget balance has shown signs of improvement. Furthermore an inadequate sequencing of reforms has contributed to the further worsening of the economic scenario during the program period.


Societies ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 58
Author(s):  
Placido

In this article I discuss how illegal substance consumption can act as a tool of resistance and as an identity signifier for young people through a covert ethnographic case study of a working-class subculture in Genoa, North-Western Italy. I develop my argument through a coupled reading of the work of the Centre for Contemporary Cultural Studies (CCCS) and more recent post-structural developments in the fields of youth studies and cultural critical criminology. I discuss how these apparently contrasting lines of inquiry, when jointly used, shed light on different aspects of the cultural practices of specific subcultures contributing to reflect on the study of youth cultures and subcultures in today’s society and overcoming some of the ‘dead ends’ of the opposition between the scholarly categories of subculture and post-subculture. In fact, through an analysis of the sites, socialization processes, and hedonistic ethos of the subculture, I show how within a single subculture there could be a coexistence of: resistance practices and subversive styles of expression as the CCCS research program posits; and signs of fragmentary and partial aesthetic engagements devoid of political contents and instead primarily oriented towards the affirmation of the individual, as argued by the adherents of the post-subcultural position.


Sign in / Sign up

Export Citation Format

Share Document