Lightning Protection of the Explosion Airflow Arc-Quenching Gap for 110 kV Transmission Lines

With the increase in the voltage level and number of transmission lines, the probability of lightning strikes on transmission lines is significantly increased, while lightning breakage accidents occur frequently. Therefore, an explosion airflow arc-quenching gap for 110 kV transmission lines was developed based on the idea of rapid extinction. A mathematical model of the detonation wave based on the CJ (Chapman–Jouget) detonation wave theory was developed to calculate the detonation air pressure and analyze its influencing factors. ANSYS software and the magnetohydrodynamic (MHD) model were used to simulate the process of detonation airflow coupled with an arc, and the simulation results indicated that the power frequency arc was evidently suppressed with the influence of airflow, which can effectively prevent arcing. A combined impulse and power frequency test and arc-quenching tests were performed to verify the effectiveness of the arc-quenching gap. The results of the combined test indicated that the arc burn time was 0.1 ms and that no power frequency continuous current was displayed. The results ensured the accuracy of the simulation model. The results of the arc-quenching tests proved that the explosion airflow can extinguish a power frequency arc with an amplitude of 40 kA in half of a power frequency arc cycle.

Stable motifs delay species loss in simulated food webs

Some three-species motifs (unique patterns of interactions between three species) are both more stable when modeled in isolation and over-represented in empirical food webs. This suggests that these motifs may reduce extinction risk for species participating in them, ultimately stabilizing the food web as a whole. We test whether a species' time to extinction following a perturbation is related to its participation in stable and unstable motifs and assess how motif roles co-vary with a species' degree or trophic level. We found that species' motif roles are related to their times to extinction following a disturbance. Specifically, participating in many omnivory motifs (whether in absolute terms, as a proportion of the species' role, or relative to other species in the network) was associated with more rapid extinction, even though omnivory has previously been identified as a stable motif. Participating in the other three stable motifs (three-species chain, apparent competition, and direct competition) was associated with longer times to extinction. While motif roles were associated with extinction risk, they also varied strongly with degree and trophic level. This means that these simpler measures of a species' role may be sufficient to roughly predict which species are most vulnerable to disturbance, but the additional information encapsulated in a motif role can further refine predictions of vulnerability. Moreover, where researchers are a priori interested in motif roles, our results confirm that these roles can be interpreted with respect to extinction risk.

A terrestrial Devonian-Carboniferous boundary section in East Greenland

Terrestrial Devonian-Carboniferous boundary sections are present in the East Greenland Devonian Basin. The boundary section on Stensiö Bjerg developed in deep, distal lake sediments with a pair of lakes representing the boundary. A diverse spore assemblage developed as the lake flooded the basin. Previously abundant spores, notably Retispora lepidophyta, Diducites spp., Rugospora radiata and all forms with bifurcate tips (Ancyrospora and Hystricosporites), then became extinct through just over a metre of section. The spore assemblage is then lost into AOM rich very high TOC% lake sediments. There is a negative δ13CTOC excursion in the Stensiö Bjerg section interpreted to represent the upper part of the positive excursion known from marine sections. The upper lake contains the simple VI spore assemblage of the earliest Carboniferous age. The correlative section on Rebild Bakker was developed in shallow proximal facies without AOM and shows that a Devonian-Carboniferous LN* to VI spore zone boundary can be picked in the lower lake based on the last occurrence of Retispora lepidophyta in an assemblage otherwise dominated by simple spores and Grandispora cornuta. Spores in this VI spore assemblage, particularly Grandispora cornuta, show sculpture malformation that is entirely characteristic of UV-B radiation damage to their DNA prior to deposition of its protective wall layer. This palynological record showing the rapid extinction of major elements within the Late Devonian microflora can be reconciled with accounts claiming there was no mass extinction of plants and spores across the boundary. The palaeobiology of the major spore groups that became extinct is reviewed.

Resilient rats exhibit better memory performances in spontaneous object-place and object recognition tasks

The present study showed that rats in the resilient group exhibited rapid extinction of conditioned fear and better performances in the spontaneous object–place and object recognition memory tasks. These findings suggest that individual resilience may depend on learning ability and memory function in rats.

The Silent Partners

Despite great advances in understanding the dynamics of viral epidemics, the emergence of rapidly spreading, highly pathogenic viruses remains a realistic and catastrophic possibility, which current health systems may not be able to fully contain. An intriguing feature in many recent zoonotic viral outbreaks is the presence of superspreaders, which are infected individuals that cause dramatically more new cases than the average. Here I study the effect of superspreaders on the early dynamics of emerging viruses that have not gained the capacity for efficient human-to-human transmission, i.e viruses with R0 < 1. I show that superspreaders have a higher chance of rapid extinction, but under crowded conditions can lead to outbreaks, causing far more cases than regular viruses. I suggest that outbreaks of highly pathogenic superspreaders are more likely when they coincide in time and space with an unrelated outbreak leading to increased hospital admission rates. These superspreader outbreaks may be difficult to detect, especially in the context of a different epidemic in progress, and can significantly affect mortality patterns observed in affected areas.

The Silent Partners

Despite great advances in understanding the dynamics of viral epidemics, the emergence of rapidly spreading, highly pathogenic viruses remains a realistic and catastrophic possibility, which current health systems may not be able to fully contain. An intriguing feature in many recent zoonotic viral outbreaks is the presence of ‘superspreaders’, which are infected individuals that cause dramatically more new cases than the average. Here I study the effect of superspreaders on the early dynamics of emerging viruses that have not gained the capacity for efficient human-to-human transmission, i.e viruses with R0 < 1. I show that superspreaders have a higher chance of rapid extinction, but under ‘crowded’ conditions can lead to ‘outbreaks’, causing far more cases than regular viruses. Hence I suggest that outbreaks of highly pathogenic superspreaders are more likely when they coincide in time and space with an unrelated outbreak leading to increased hospital admission rates. These superspreader outbreaks may be difficult to detect, especially in the context of a different epidemic in progress, and can significantly affect mortality patterns observed in affected areas.

A Study on the Ganoderma Lucidum of Warri South Local Government Area

A study on the medicinal mushroom (Ganoderma lucidum) was conducted from May to July 2015 to document the medicinal importance of Ganoderma lucidum “Itu” by the Warri South people in Warri, Delta State, Nigeria. This mushroom was identified and collected during field trip and visits to traditional medical practitioners. Four mushrooms species were identified out of which 2 are edible, 1 is used medicinally and 1 is feared by the locals and trial’s of the community because of its poisonous content. These mushroom were briefly described, their uses, local names and part used were listed. These mushrooms are faced with rapid extinction because its knowledge and use are not passed to younger generation.

Combining PCR and CT testing for COVID

We analyze the effect of using a screening CT-scan for evaluation of potential COVID-19 infections in order to isolate and perform contact tracing based upon a viral pneumonia diagnosis. RT-PCR is then used for continued isolation based upon a COVID diagnosis. Both the low false negative rates and rapid results of CT-scans lead to dramatically reduced transmission. The reduction in cases after 60 days with widespread use of CT-scan screening compared to PCR by itself is as high as 50×, and the reduction of effective reproduction rate R(t) is 0.20. Our results imply that much more rapid extinction of COVID is possible by combining social distancing with CT-scans and contact tracing.