2,126 research outputs found

    Editorial

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    Ecotoxicity of nanomaterials in relation to the freshwater blackworm, Lumbriculus variegatus

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    Nanotechnologies are increasing being applied within consumer products, science, medicine, engineering and industrial processes. Due to their small size and high reactivity, nanoparticles (NPs) possess a potentially unique risk towards humans and the environment. Although the aquatic environment is predicted to be the final recipient of nano-wastes, little is known regarding the potential toxicity of NPs towards aquatic species. Within this thesis, the toxicity of two reference nanoparticles: silver (NM-300K) and titanium dioxide (NM-104) were investigated in relation to the freshwater oligochaete, Lumbriculus variegatus in artificial water and sediment. Greater toxicity was observed for NM-300K towards L. variegatus in both short-term (96-hour) water and long-term (28-days) sediment exposures. Sub-lethal NM-300K aquatic exposures (0.2 mg/L) led to an inhibition of L. variegatus swimming behaviours designed for the escape of predation as well as increases in the antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT). Increases in SOD and CAT indicate the onset of oxidative stress, however, no oxidative damage (as measured by lipid peroxidation) was observed. The inclusion of Suwannee River humic acid (5mg/L) as a natural organic matter (NOM) source generally reduced NM-300K toxicity in aquatic exposures – improving swimming behaviours and limiting SOD and CAT activities to those recorded in control exposures. Although NM-300K displayed greater toxicity than NM-104 in sediment exposures, 100% L. variegatus mortality was only observed at extremely high, potentially environmentally irrelevant concentrations (1333.33 mg/kg). The results of this thesis demonstrate the importance of water and sediment NP toxicity testing in relation to L. variegatus using traditional and newly emerging endpoints and variations to abiotic conditions

    I like who you like, but only if I like you: Female character affects mate-choice copying.

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    Mate-choice copying is shown when women imitate the mate-choice preferences of other women. We propose that the preferences of women with a pleasant character should be more influential than those of women with an unpleasant character and further suggest that this should apply only when the female demonstrates active interest in the male, rather than disinterest. Here, we presented women as having either a pleasant or unpleasant character and found that observing pleasant women looking at men increased women’s preferences for those men, while observing unpleasant women looking at men had no effect on women’s preferences. Furthermore, the effect of being looked at by a pleasant woman was heightened when she was smiling. This suggests that judgements of facial attractiveness can be socially influenced and that character affects the degree of influence

    Editorial

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    Not just for the wealthy: Rethinking farmed fish consumption in the Global South

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    Aquaculture’s contributions to food security in the Global South are widely misunderstood. Dominant narratives suggest that aquaculture contributes mainly to international trade benefiting richer Northern consumers, or provides for wealthy urban consumers in Southern markets. On the supply side, the literature promotes an idealized vision of ‘small-scale’, low input, semi-subsistence farming as the primary means by which aquaculture can contribute to food security, or emphasizes the role of ‘industrial’ export oriented aquaculture in undermining local food security. In fact, farmed fish is produced predominantly by a ‘missing middle’ segment of commercial and increasingly intensive farms, and overwhelmingly remains in Southern domestic markets for consumption by poor and middle income consumers in both urban and rural areas, making an important but underappreciated contribution to global food security

    Let them eat carp: Fish farms are helping to fight hunger

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    First paragraph: Over the past three decades, the global aquaculture industry has risen from obscurity to become a critical source of food for millions of people. In 1990, only 13 percent of world seafood consumption was farmed; by 2014, aquaculture was providing more than half of the fish consumed directly by human beings.  The boom has made farmed fish like shrimp, tilapia and pangasius catfish – imported from countries such as Thailand, China and Vietnam – an increasingly common sight in European and North American supermarkets. As a result, much research on aquaculture has emphasized production for export.  This focus has led scholars to question whether aquaculture contributes to the food security of poorer people in producing countries. Many have concluded it does not. Meanwhile, the industry’s advocates often emphasize the potential for small-scale farms, mainly growing fish for home consumption, to feed the poor. Farms of this kind are sometimes claimed to account for 70 to 80 percent of global aquaculture production

    Self-Directed Support: A Review of the Barriers and Facilitators

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    This is a report on the published literature on the barriers and facilitators of self- directed support. It was undertaken to inform a research study funded by the Scottish Government 2009-2011 that is evaluating initiatives in three local authorities. These initiatives aim to improve take up of self-directed support for people eligible for social care and other public funds. The three test site areas are working to reduce bureaucracy; to make the processes easy and 'light touch'; and to provide training and leadership to people working on these developments. Scottish Government has provided extra money to assist these three authorities and to help people in other areas learn from their experiences

    Hormesis depends upon the life-stage and duration of exposure: examples for a pesticide and a nanomaterial

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    Tests to assess toxic effects on the reproduction of adult C. elegans after 72 h exposure for two chemicals, (3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU)), also known as diuron, and silver nanoparticles (Ag NPs) indicated potential, although not significant hormesis. Follow up toxicity tests comparing the potential hormesis concentrations with controls at high replication confirmed that the stimulatory effect was repeatable and also statistically significant within the test. To understand the relevance of the hormesis effects for overall population fitness, full life-cycle toxicity tests were conducted for each chemical. When nematodes were exposed to DCMU over the full life-span, the hormesis effect for reproduction seen in short-term tests was no longer evident. Further at the putative hormesis concentrations, a negative effect of DCMU on time to maturation was also seen. For the Ag NPs, the EC50 for effects on reproduction in the life-cycle exposure was substantially lower than in the short-term test, the EC50s estimated by a three parameter log logistic model being 2.9 mg/L and 0.75 mg/L, respectively. This suggests that the level of toxicity for Ag NPs for C. elegans reproduction is dependant on the life stage exposed and possibly the duration of the exposure. Further, in the longer duration exposures, hormesis effects on reproduction seen in the short-term exposures were no longer apparent. Instead, all concentrations reduced both overall brood size and life-span. These results for both chemicals suggest that the hormesis observed for a single endpoint in short-term exposure may be the result of a temporary reallocation of resources between traits that are not sustained over the full life-time. Such reallocation is consistent with energy budget theories for organisms subject to toxic stres

    Adaptive Deep Brain Stimulation: From Experimental Evidence Toward Practical Implementation.

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    Closed-loop adaptive deep brain stimulation (aDBS) can deliver individualized therapy at an unprecedented temporal precision for neurological disorders. This has the potential to lead to a breakthrough in neurotechnology, but the translation to clinical practice remains a significant challenge. Via bidirectional implantable brain-computer-interfaces that have become commercially available, aDBS can now sense and selectively modulate pathophysiological brain circuit activity. Pilot studies investigating different aDBS control strategies showed promising results, but the short experimental study designs have not yet supported individualized analyses of patient-specific factors in biomarker and therapeutic response dynamics. Notwithstanding the clear theoretical advantages of a patient-tailored approach, these new stimulation possibilities open a vast and mostly unexplored parameter space, leading to practical hurdles in the implementation and development of clinical trials. Therefore, a thorough understanding of the neurophysiological and neurotechnological aspects related to aDBS is crucial to develop evidence-based treatment regimens for clinical practice. Therapeutic success of aDBS will depend on the integrated development of strategies for feedback signal identification, artifact mitigation, signal processing, and control policy adjustment, for precise stimulation delivery tailored to individual patients. The present review introduces the reader to the neurophysiological foundation of aDBS for Parkinson's disease (PD) and other network disorders, explains currently available aDBS control policies, and highlights practical pitfalls and difficulties to be addressed in the upcoming years. Finally, it highlights the importance of interdisciplinary clinical neurotechnological research within and across DBS centers, toward an individualized patient-centered approach to invasive brain stimulation. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society
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