The magnetic viscosity (MV) effects observed at time scales between 0.01 and 10 ms at Opemiska are associated with magnetic grains of variable size in rocks. Recent observations made during a ground time-domain electromagnetic (TDEM) survey at Opemiska are consistent with four aspects of the spatial and amplitude characteristics of a MV response: (1) the ∂B z ∕∂t decay rate is roughly proportional to 1∕t 1þα , where −0.4 < α < 0.4, (2) the anomalies are mainly visible on the z-component, when the EM receiver sensor is located inside or just outside the transmitter loop, (3) there is no obvious xor y-component response, and (4) the sites where MV effects are seen in the TDEM data are coincident with an airborne magnetic anomaly. Previous studies have demonstrated that MV could be caused by (1) fine-grained particles of maghemite or magnetite in the overburden, regolith, or soil that were formed through lateritic weathering processes, (2) volcanic glass shards from tuff containing approximately 1% by weight magnetite, which occur as grains approximately 0.002-0.01 μm in size precipitated in a spatially uniform way, or (3) from the Gallionella bacterium that precipitates ferrihydrite that oxidizes to nanocrystalline maghemite aggregates. The sites investigated at Opemiska are outcropping and well-exposed with relatively little or no overburden, and they are unfavorable for the formation of maghemite; hence, it is assumed that the source of MV seen at Opemiska cannot be the maghemite, or the other aforementioned causes. Hand samples were collected from Opemiska to identify the minerals present. Polished thin sections observed under an optical reflecting microscope identified the accessory minerals magnetite, ilmenite, and pyrrhotite, all known for their relatively high magnetic susceptibility. The use of the scanning electron microscope confirmed fine-grained magnetite grains as small as 0.667 μm. An electromagnetic induction spectrometer confirmed the viscous nature of the susceptibility of the Opemiska samples. This suggests that MV could originate not only from fine-grained magnetite and maghemite particles located in the weathered regolith but also from other iron oxides and magnetic minerals embedded in the rock itself.
Memory for complex content is severely impaired in patients with schizophrenia spectrum disorders, which might make processing of daily information such as news and commercials particularly challenging. The goal of the present study was to assess the impairment of everyday memory in patients with schizophrenia. Healthy controls (HC) and patients with schizophrenia (SZ) were asked to watch a selection of six news segments and six commercials and complete a recognition task on the content of these video clips. All participants completed a neuropsychological test battery comprising measures of attention, working and episodic memory, and executive function. The total number of correctly recognized items was significantly lower in the SZ group. In contrast, the number of false recognitions was alike in both news and commercials paradigm. We conclude that memory in patients with schizophrenia is more prone to omissions than distortions for complex everyday stimuli. The results offer further support for impaired binding in SZ patients. Memory in SZ suffices to reject false multi-feature items on grounds of identifying at least one feature as incorrect but does not suffice to recall all features of a complex item and affirm it as correct.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.