Publications by authors named "A J Geiger"

This paper focuses on the retrieval of refractivity fields from GNSS measurements by means of least-squares collocation. Collocation adjustment estimates parameters that relate delays and refractivity without relying on a grid. It contains functional and stochastic models that define the characteristics of the retrieved refractivity fields.

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Ubiquitin C-terminal hydrolase 37 (UCH37 also known as UCHL5) is a conserved deubiquitinating enzyme (DUB) with dual roles in proteasomal degradation and chromatin remodeling in humans. Its Plasmodium falciparum ortholog, PfUCH37, is unusual in that it possesses both DUB and deneddylating activities. While PfUCH37 is enriched in proteasome preparations, its direct interaction and broader functions in Plasmodium remain unclear, particularly given the absence of the chromatin remodeling complex INO80 homologs.

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Mechanisms by which G-patch activators tune the processive multi-tasking ATP-dependent RNA helicase Prp43 (DHX15 in humans) to productively remodel diverse RNA:protein complexes remain elusive. Here, a comparative study between a herein and previously characterized activators, Tma23 and Pxr1, respectively, defines segments that organize Prp43 function during ribosome assembly. In addition to the activating G-patch, we discover an inhibitory segment within Tma23 and Pxr1, I-patch, that restrains Prp43 ATPase activity.

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Objective: The current study sought to characterize the relationship of the N400 (N4) effect event-related potential to Alzheimer's disease (AD) biomarkers and broader cognition in older adults on the late-life cognitive continuum.

Method: Participants who were cognitively intact (n = 43), or had amnestic mild cognitive impairment (MCI; n = 19), or mild AD (n = 12), completed a word-pair judgement task during concurrent EEG recording to elicit the N400. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and biomarker data (PET-imaged beta-amyloid (aβ) deposition, apolipoprotein-E ε4 (APOE4) allele status, hippocampal volumes) were collected as part of a larger study.

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Circadian clocks control most physiological processes of many species. We specifically wanted to investigate the influence of environmental and endogenous rhythms and their interplay on electrophysiological dynamics of neuronal populations. Therefore, we measured local field potential (LFP) time series in wild-type and Cryptochrome 1 and 2 deficient (Cry1/2) mice in the suprachiasmatic nucleus and the nucleus accumbens under regular light conditions and constant darkness.

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