43 research outputs found

    Little raven (Corvus mellori) as an egg predator of other bird species

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     Little ravens were major predators of ground-nesting red-capped Plover and burrow-nesting Little penguin eggs. Ravens also congregated at the breeding sites of these two species to exploit eggs. As raven numbers increase with human habitation of land, their impact on other bird species needs to be monitored and managed

    Occurrence of Fungi and Fungal Toxins in Fish Feed during Storage

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    Periods of unfavorable storing conditions can lead to changes in the quality of fish feeds, as well as the development of relevant mycotoxins. In the present study, a commercial fish feed was stored under defined conditions for four weeks. The main findings indicate that even storing fish feeds under unsuitable conditions for a short duration leads to a deterioration in quality. Mycotoxin and fungal contamination were subsequently analyzed. These investigations confirmed that different storage conditions can influence the presence of fungi and mycotoxins on fish feed. Notably, ochratoxin A (OTA) was found in samples after warm (25 °C) and humid (>60% relative humidity) treatment. This confirms the importance of this compound as a typical contaminant of fish feed and reveals how fast this mycotoxin can be formed in fish feed during storage

    A sensitivity matrix approach using two-stage optimization for voltage regulation of LV networks with high PV penetration

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    The occurrence of voltage violations is a major deterrent for absorbing more rooftop solar power into smart Low-Voltage Distribution Grids (LVDGs). Recent studies have focused on decentralized control methods to solve this problem due to the high computational time in performing load flows in centralized control techniques. To address this issue, a novel sensitivity matrix was developed to estimate the voltages of the network by replacing load flow simulations. In this paper, a Centralized Active, Reactive Power Management System (CARPMS) is proposed to optimally utilize the reactive power capability of smart Photovoltaic (PV) inverters with minimal active power curtailment to mitigate the voltage violation problem. The developed sensitivity matrix is able to reduce the time consumed by 55.1% compared to load flow simulations, enabling near-real-time control optimization. Given the large solution space of power systems, a novel two-stage optimization is proposed, where the solution space is narrowed down by a Feasible Region Search (FRS) step, followed by Particle Swarm Optimization (PSO). The failure of standalone PSO to converge to a feasible solution for 34% of the scenarios evaluated further validates the necessity of the two-stage optimization using FRS. The performance of the proposed methodology was analysed in comparison to the load flow method to demonstrate the accuracy and the capability of the optimization algorithm to mitigate voltage violations in near-real time. The deviations of the mean voltages of the proposed methodology from the load flow method were: 6.5×10−3 p.u for reactive power control using Q-injection, 1.02×10−2 p.u for reactive power control using Q-absorption, and 0 p.u for active power curtailment case

    Unbalanced relationships: insights into the interaction between gut microbiota, geohelminths, and schistosomiasis

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    Hosts and their microbiota and parasites have co-evolved in an adaptative relationship since ancient times. The interaction between parasites and intestinal bacteria in terms of the hosts’ health is currently a subject of great research interest. Therapeutic interventions can include manipulations of the structure of the intestinal microbiota, which have immunological interactions important for modulating the host’s immune system and for reducing inflammation. Most helminths are intestinal parasites; the intestinal environment provides complex interactions with other microorganisms in which internal and external factors can influence the composition of the intestinal microbiota. Moreover, helminths and intestinal microorganisms can modulate the host’s immune system either beneficially or harmfully. The immune response can be reduced due to co-infection, and bacteria from the intestinal microbiota can translocate to other organs. In this way, the treatment can be compromised, which, together with drug resistance by the parasites makes healing even more difficult. Thus, this work aimed to understand interactions between the microbiota and parasitic diseases caused by the most important geohelminths and schistosomiasis and the consequences of these associations
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