334 research outputs found
A note on Gromov-Hausdorff-Prokhorov distance between (locally) compact measure spaces
We present an extension of the Gromov-Hausdorff metric on the set of compact
metric spaces: the Gromov-Hausdorff-Prokhorov metric on the set of compact
metric spaces endowed with a finite measure. We then extend it to the
non-compact case by describing a metric on the set of rooted complete locally
compact length spaces endowed with a locally finite measure. We prove that this
space with the extended Gromov-Hausdorff-Prokhorov metric is a Polish space.
This generalization is needed to define L\'evy trees, which are (possibly
unbounded) random real trees endowed with a locally finite measure
Polycystins From Mechanosensation to Gene Regulation
AbstractPolycystin proteins have been suggested to form mechanosensory transduction complexes involved in a variety of biological functions including sperm fertilization, mating behavior, and asymmetric gene expression in different species. Furthermore, their dysfunction is the cause of cyst formation in human kidney disease. This review focuses on the pros and cons of their candidacy as mechanically gated channels and on recent findings that have significantly advanced our physiological insight
Accès au marché et commercialisation de produits agricoles : Valorisation d'initiatives de producteurs
Les producteurs d’Afrique subsaharienne doivent surmonter de nombreux obstacles pour écouler leurs produits agricoles : instabilité des prix, infrastructures déficientes, manque d’informations commerciales, difficultés d’accès aux marchés… Cet ouvrage rassemble plusieurs études de cas illustrant les initiatives de producteurs isolés et d’organisations paysannes pour améliorer l’accès aux marchés. Dans sa conclusion, il propose plusieurs recommandations visant à promouvoir de telles actions
Market access and agricultural product marketing: Promoting farmer initiatives
Farmers in sub-Saharan Africa face significant obstacles in selling their agricultural products, including unstable prices, poor infrastructure, limited market information and lack of market access. This book brings together case-studies of initiatives developed by individual farmers and farmers' organisations to improve market access, and concludes with recommendations for supporting such initiatives
Mechano-Gated Ion Channels in Sensory Systems
Living organisms sense their physical environment through cellular mechanotransduction, which converts mechanical forces into electrical and biochemical signals. In turn, signal transduction serves a wide variety of functions, from basic cellular processes as diverse as proliferation, differentiation, migration, and apoptosis up to some of the most sophisticated senses, including touch and hearing. Accordingly, defects in mechanosensing potentially lead to diverse diseases and disorders such as hearing loss, cardiomyopathies, muscular dystrophies, chronic pain, and cancer. Here, we review the status of mechanically activated ion channel discovery and discuss current challenges to define their properties and physiological functions
Loom: Exploiting Weight and Activation Precisions to Accelerate Convolutional Neural Networks
Loom (LM), a hardware inference accelerator for Convolutional Neural Networks
(CNNs) is presented. In LM every bit of data precision that can be saved
translates to proportional performance gains. Specifically, for convolutional
layers LM's execution time scales inversely proportionally with the precisions
of both weights and activations. For fully-connected layers LM's performance
scales inversely proportionally with the precision of the weights. LM targets
area- and bandwidth-constrained System-on-a-Chip designs such as those found on
mobile devices that cannot afford the multi-megabyte buffers that would be
needed to store each layer on-chip. Accordingly, given a data bandwidth budget,
LM boosts energy efficiency and performance over an equivalent bit-parallel
accelerator. For both weights and activations LM can exploit profile-derived
perlayer precisions. However, at runtime LM further trims activation precisions
at a much smaller than a layer granularity. Moreover, it can naturally exploit
weight precision variability at a smaller granularity than a layer. On average,
across several image classification CNNs and for a configuration that can
perform the equivalent of 128 16b x 16b multiply-accumulate operations per
cycle LM outperforms a state-of-the-art bit-parallel accelerator [1] by 4.38x
without any loss in accuracy while being 3.54x more energy efficient. LM can
trade-off accuracy for additional improvements in execution performance and
energy efficiency and compares favorably to an accelerator that targeted only
activation precisions. We also study 2- and 4-bit LM variants and find the the
2-bit per cycle variant is the most energy efficient
Pharmacological Dissection and Distribution of NaN/Nav1.9, T-type Ca2+ Currents, and Mechanically Activated Cation Currents in Different Populations of DRG Neurons
Low voltage–activated (LVA) T-type Ca2+ (ICaT) and NaN/Nav1.9 currents regulate DRG neurons by setting the threshold for the action potential. Although alterations in these channels have been implicated in a variety of pathological pain states, their roles in processing sensory information remain poorly understood. Here, we carried out a detailed characterization of LVA currents in DRG neurons by using a method for better separation of NaN/Nav1.9 and ICaT currents. NaN/Nav1.9 was inhibited by inorganic ICa blockers as follows (IC50, μM): La3+ (46) > Cd2+ (233) > Ni2+ (892) and by mibefradil, a non-dihydropyridine ICaT antagonist. Amiloride, however, a preferential Cav3.2 channel blocker, had no effects on NaN/Nav1.9 current. Using these discriminative tools, we showed that NaN/Nav1.9, Cav3.2, and amiloride- and Ni2+-resistant ICaT (AR-ICaT) contribute differentially to LVA currents in distinct sensory cell populations. NaN/Nav1.9 carried LVA currents into type-I (CI) and type-II (CII) small nociceptors and medium-Aδ–like nociceptive cells but not in low-threshold mechanoreceptors, including putative Down-hair (D-hair) and Aα/β cells. Cav3.2 predominated in CII-nociceptors and in putative D-hair cells. AR-ICaT was restricted to CII-nociceptors, putative D-hair cells, and Aα/β-like cells. These cell types distinguished by their current-signature displayed different types of mechanosensitive channels. CI- and CII-nociceptors displayed amiloride-sensitive high-threshold mechanical currents with slow or no adaptation, respectively. Putative D-hair and Aα/β-like cells had low-threshold mechanical currents, which were distinguished by their adapting kinetics and sensitivity to amiloride. Thus, subspecialized DRG cells express specific combinations of LVA and mechanosensitive channels, which are likely to play a key role in shaping responses of DRG neurons transmitting different sensory modalities
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