Hippocampal subfields and limbic white matter jointly predict learning rate in older adults

First published online: 04 December 2019Age-related memory impairments have been linked to differences in structural brain parameters, including cerebral white matter (WM) microstructure and hippocampal (HC) volume, but their combined influences are rarely investigated. In a population-based sample of 337 older participants aged 61-82 years (Mage = 69.66, SDage = 3.92 years), we modeled the independent and joint effects of limbic WM microstructure and HC subfield volumes on verbal learning. Participants completed a verbal learning task of recall over five repeated trials and underwent magnetic resonance imaging (MRI), including structural and diffusion scans. We segmented three HC subregions on high-resolution MRI data and sampled mean fractional anisotropy (FA) from bilateral limbic WM tracts identified via deterministic fiber tractography. Using structural equation modeling, we evaluated the associations between learning rate and latent factors representing FA sampled from limbic WM tracts, and HC subfield volumes, and their latent interaction. Results showed limbic WM and the interaction of HC and WM-but not HC volume alone-predicted verbal learning rates. Model decomposition revealed HC volume is only positively associated with learning rate in individuals with higher WM anisotropy. We conclude that the structural characteristics of limbic WM regions and HC volume jointly contribute to verbal learning in older adults

本邦人大腿骨傾斜角度ノレントゲン的測定ニ就テ(第一囘報告)

Once every menstrual cycle, eggs are ovulated into the oviduct where they await fertilization. The ovulated eggs are arrested in metaphase of the second meiotic division, and only complete meiosis upon fertilization. It is crucial that the maintenance of metaphase arrest is tightly controlled, because the spontaneous activation of the egg would preclude the development of a viable embryo (Zhang et al. 2015 J. Genet. Genomics 42, 477-485. (doi:10.1016/j.jgg.2015.07.004); Combelles et al. 2011 Hum. Reprod. 26, 545-552. (doi:10.1093/humrep/deq363); Escrich et al. 2011 J. Assist. Reprod. Genet. 28, 111-117. (doi:10.1007/s10815-010-9493-5)). However, the mechanisms that control the meiotic arrest in mammalian eggs are only poorly understood. Here, we report that a complex of BTG4 and CAF1 safeguards metaphase II arrest in mammalian eggs by deadenylating maternal mRNAs. As a follow-up of our recent high content RNAi screen for meiotic genes (Pfender et al. 2015 Nature 524, 239-242. (doi:10.1038/nature14568)), we identified Btg4 as an essential regulator of metaphase II arrest. Btg4-depleted eggs progress into anaphase II spontaneously before fertilization. BTG4 prevents the progression into anaphase by ensuring that the anaphase-promoting complex/cyclosome (APC/C) is completely inhibited during the arrest. The inhibition of the APC/C relies on EMI2 (Tang et al. 2010 Mol. Biol. Cell 21, 2589-2597. (doi:10.1091/mbc.E09-08-0708); Ohe et al. 2010 Mol. Biol. Cell 21, 905-913. (doi:10.1091/mbc.E09-11-0974)), whose expression is perturbed in the absence of BTG4. BTG4 controls protein expression during metaphase II arrest by forming a complex with the CAF1 deadenylase and we hypothesize that this complex is recruited to the mRNA via interactions between BTG4 and poly(A)-binding proteins. The BTG4-CAF1 complex drives the shortening of the poly(A) tails of a large number of transcripts at the MI-MII transition, and this wave of deadenylation is essential for the arrest in metaphase II. These findings establish a BTG4-dependent pathway for controlling poly(A) tail length during meiosis and identify an unexpected role for mRNA deadenylation in preventing the spontaneous activation of eggs

New options for pest management in horticultural crop-based agroecosystems of Sudano-Sahelian Africa in the climate change context

In the climate change context, ICRISAT is promoting water-saving cropping systems mixing food and horticultural crops for the Sudano-Sahelian zone of Western Africa. ICRISAT's partners in Niger (CIRAD, the University of Niamey and INRAN) are seeking ways to minimize the impact of crop pests in these systems, using the agroecological approach. Following encouraging earlier results, agroecological management options were further investigated in 2010 for the major pests of okra, jujube tree and watermelon, the major horticultural crops in the water harvesting-based Bio-Reclamation of Degraded Lands (BDL) and Dryland Eco-Farm (DEF) systems. Pigeon pea was evaluated as a trap crop for regulating infestation of okra by the fruit worm Helicoverpa armigera in a design with four treatments (unbordered cypermethrin-sprayed and unsprayed controls, and two pigeon pea-bordered unsprayed treatments, with an early and an extra-early cultivar). On the other hand, the foliage of 4 trees in a jujube orchard was sprayed with GF-120 (mixture of food attractant and biological insecticide) with 2 trees remaining unsprayed. White linen sheets were placed under the sprayed trees, in view of collecting the flies that would have ingested the bait, and ripe jujube fruits were harvested and weighed. Results on okra suggested a new ''top-down" regulation process, further to the mere "bottom-up" trap-cropping effect, which questions the relevance of both attempting to reinforce the "pull" trap-cropping effect with a ''push"' effect using insect-repellent sprays on the main okra crop, and playing on a barrier effect of the perirneter trap crop against piercing-sucking homopteran pests. Results on jujube suggested that GF-120 could be used both as a repellent to protect jujube trees from the fruit fly Carpomya incompleta, and as an attractant to protect water melon, which is part of the DEF system, from Dacus spp., thus killing two birds with one stone. (Résumé d'auteur

A holomorphic representation of the Jacobi algebra

A representation of the Jacobi algebra $\mathfrak{h}_1\rtimes \mathfrak{su}(1,1)$ by first order differential operators with polynomial coefficients on the manifold $\mathbb{C}\times \mathcal{D}_1$ is presented. The Hilbert space of holomorphic functions on which the holomorphic first order differential operators with polynomials coefficients act is constructed.Comment: 34 pages, corrected typos in accord with the printed version and the Errata in Rev. Math. Phys. Vol. 24, No. 10 (2012) 1292001 (2 pages) DOI: 10.1142/S0129055X12920018, references update

Pamela: development of the RF system for a non-relativistic non-scaling FFAG

The PAMELA project(Particle Accelerator For MEdical Applications) currently consists of the design of a particle therapy facility. The project, which is in the design phase, contains Non-Scaling FFAG, particle accelerator capable of rapid beam acceleration, giving a pulse repetition rate of 1kHz, far beyond that of a conventional synchrotron. To realise the repetition rate, a key component of the accelerator is the rf accelerating system. The combination of a high energy gain per turn and a high repetition rate is a significant challenge. In this paper, options for the rf system of the proton ring and the status of development are presented