387 research outputs found
Tricking AI chips into simulating the human brain:A detailed performance analysis
In recent years, significant strides in Artificial Intelligence (AI) have led to various practical applications, primarily centered around training and deployment of deep neural networks (DNNs). These applications, however, require considerable computational resources, predominantly reliant on modern Graphics-Processing Units (GPUs). Yet, the quest for larger and faster DNNs has spurred the creation of specialized AI chips and efficient Machine-Learning (ML) software tools like TensorFlow and PyTorch have been developed for striking a balance between usability and performance. Simultaneously, the field of computational neuroscience shares a similar quest for increased computational power to simulate more extensive and detailed brain models, while also keeping usability high. Although GPUs have also entered this field, programming complexity remains high, resulting in cumbersome simulations. Inspired by AI progress, we introduce a workflow for easily accelerating brain simulations using TensorFlow and evaluate the performance of various, cutting-edge AI chips – including the Graphcore Intelligence-Processing Unit (IPU), GroqChip, Nvidia GPU with Tensor Cores, and Google Tensor-Processing Unit (TPU) – when simulating a biologically detailed as well as simpler brain models. Our model simulations explore the architectural tradeoffs of a modern-day CPU and these four AI platforms by varying computational density, memory requirements and floating-point numerical accuracy. Results show that the GroqChip achieves the best performance for small networks, yet is unable to simulate large-scale networks. At the scale of mammalian brains, the GPU, IPU and TPU achieve speedups ranging from 29x to 1,208x times over CPU runtimes. Remarkably, the TPU sets a new record for the largest, real-time simulation of the inferior-olivary nucleus in the brain. Reduced-accuracy floating-point implementations make some simulation results unreliable for brain research, notably for the GroqChip. Consequently, this work underscores the potential of ML libraries for accelerating brain simulations as well as the critical role of AI-chip numerical accuracy for biophysically realistic brain models.</p
Morphology and function of the forelimb in arboreal frogs: specializations for grasping ability.
Frogs are characterized by a unique morphology associated with their saltatory lifestyle. Although variation in the form and function of the pelvic girdle and associated appendicular system related to specialized locomotor modes such as swimming or burrowing has been documented, the forelimbs have typically been viewed as relatively unspecialized. Yet, previous authors have noted versatility in forelimb function among arboreal frogs associated with feeding. Here we study the morphology and function of the forelimb and hand during locomotion in two species of arboreal frogs (Litoria caerulea and Phyllomedusa bicolor). Our data show a complex arrangement of the distal forelimb and hand musculature with some notable differences between species. Analyses of high‐speed video and video fluoroscopy recordings show that forelimbs are used in alternating fashion in a diagonal sequence footfall pattern and that the position of the hand is adjusted when walking on substrates of different diameters. Electromyographic recordings show that the flexors of the hand are active during substrate contact, suggesting the use of gripping to generate a stabilizing torque. Measurements of grasping forces in vivo and during stimulation experiments show that both species, are capable of executing a so‐called power grip but also indicates marked differences between species, in the magnitude of forces generated. Stimulation experiments showed an increased control of digit flexion in the more specialized of the two species, allowing it to execute a precision grip paralleled only by that seen in primates.Fil: Manzano, Adriana Silvina. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; ArgentinaFil: Abdala, Virginia Sara Luz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biodiversidad Neotropical. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical. Instituto de Biodiversidad Neotropical; ArgentinaFil: Herrel, Anthony. University of Antwerp; Bélgic
Role of the finger flexors in rheumatoid deformities of the metacarpophalangeal joints
It is proposed that rheumatoid deformity of the central three metacarpophalangeal joints is caused primarily by the flexor tendons acting on diseased joint restraints. During pinch and grasp the tendons bend volarly and ulnarly at the tunnel mouth; the resultant pulley forces damage the supporting collateral ligaments, especially on the radial side. The flexor tendons and proximal phalanges can then displace volarly and ulnarly, and the fingers deviate ulnarly. In the fifth digit, ulnar deviation apparently results from the incompletely opposed pull of the abductor digiti quinti.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37698/1/1780070503_ftp.pd
Reducing progression of knee OA features assessed by MRI in overweight and obese women: Secondary outcomes of a preventive RCT
Objective: To evaluate the preventive effects of a randomized controlled trial on progression of Magnetic Resonance Imaging (MRI) features of knee osteoarthritis (OA) in overweight and obese women. Design: In a 2 × 2 factorial design, 2.5 years effects of a diet and exercise program and of glucosamine sulphate (double-blind, placebo-controlled) were evaluated in 407 middle-aged women with body mass index (BMI) ≥ 27 kg/m2 without clinical signs of knee OA at baseline (ISRCTN 42823086). MRIs were scored with the MRI Osteoarthritis Knee Score (MOAKS). Progression was defined for bone marrow lesions (BMLs), cartilage defects, osteophytes, meniscal abnormalities and meniscal extrusion. Analyses on knee level were performed over the four intervention groups using adjusted Generalized Estimating Equations (GEE). Results: 687 knees of 347 women with mean age 55.7 years (±3.2 SD) and mean BMI 32.3 kg/m2 (±4.2 SD) were analyzed. Baseline prevalence was 64% for BMLs, 70% for cartilage defects, 24% for osteophytes, 66% for meniscal abnormalities and 52% for meniscal extrusions. The diet and exercise program + placebo intervention showed significantly less progression of meniscal extrusion compared to placebo only (12% vs 22%, OR 0.50, 95% CI [0.27-0.92]). The interventions did not result in significant differences on other OA MRI features. Conclusions: In subjects at high risk for future knee OA development, a diet and exercise program, glucosamine sulphate and their combination showed small and mainly non-significant effects on the progression of OA MRI features. Only progression of meniscal extrusion was significantly diminished by the diet and exercise program
Association of urinary biomarker COLL2-1NO-2 with incident clinical and radiographic knee OA in overweight and obese women
__Objective:__ To investigate the association between urinary biomarker Coll2-1NO2 (uColl2-1NO2) and incident knee OA after 2.5 years follow-up in middle-aged overweight and obese women at high risk for knee osteoarthritis (OA).
__Design:__ Data were used from PROOF, a randomized controlled trial with 2.5 years follow-up evaluating the preventive effects of a diet and exercise program and oral glucosamine sulphate (double blind and placebo controlled), on development of incident knee OA in women with body mass index≥27kg/m2 without signs of knee OA at baseline. Baseline and 2.5 years uColl2-1NO2 concentrations were assessed with enzyme-linked immunosorbent assay (ELISA). Primary outcome measure was incidence of knee OA in one or both knees, defined as incidence of either Kellgren & Lawrence grade ≥2, joint space narrowing of ≥1.0mm or knee OA according to the combined clinical and radiographic ACR-criteria. We used binary logistic regression for the association analyses.
__Results:__ 254 women were available for analyses. At 2.5 years follow-up, incident knee OA was present in 72 of 254 women (28.3%). An inversed association was found between baseline uColl2-1NO2 and incident knee OA at 2.5 years (OR 0.74, 95% CI 0.55-0.99). The concentration at 2.5 years and the change in concentration over 2.5 years did not show significant associations with the outcome. Conclusions: In overweight and obese middle-aged women, not higher but lower baseline uColl2-1NO2 concentration was significantly associa
Analysing finger interdependencies during the Purdue Pegboard Test and comparative activities of daily living
Study Design: Bench, Cross-sectional
Introduction: Information obtained from dexterity tests is an important component of a comprehensive examination of the hand.
Purpose of the Study: To analyse and compare finger interdependencies during the performance of the Purdue Pegboard Test and comparative daily tasks.
Methods: A method based on the optoelectronic kinematic analysis of the precision grip style and on the calculation of cross-correlation coefficients between relevant joint angles, which provided measures of the degree of finger coordination, was conducted on 10 healthy participants performing the Purdue Pegboard Test and two comparative daily living tasks.
Results: Daily tasks showed identifiable interdependencies patterns between the metacarpophalangeal joints of the fingers involved in the grip. Tasks related to activities of daily living resulted in significantly higher cross-correlation coefficients across subjects and across movements during the formation and manipulation phases of the tasks (0.7-0.9), while the release stage produced significantly lower movement correlation values (0.3-0.7). Contrarily, the formation and manipulation stages of the Purdue Pegboard Test showed low finger correlation across most subjects (0.2-0.6), while the release stage resulted in the highest values for all relevant movements (0.65-0.9).
Discussion: Interdependencies patterns were consistent for the activities of daily living, but differ from the patterns observed from the Purdue Pegboard Test.
Conclusions: The Purdue Pegboard Test does not compare well with the whole range of finger movements that account for hand performance during daily tasks
Recognition and localization of relevant human behavior in videos, SPIE,
ABSTRACT Ground surveillance is normally performed by human assets, since it requires visual intelligence. However, especially for military operations, this can be dangerous and is very resource intensive. Therefore, unmanned autonomous visualintelligence systems are desired. In this paper, we present an improved system that can recognize actions of a human and interactions between multiple humans. Central to the new system is our agent-based architecture. The system is trained on thousands of videos and evaluated on realistic persistent surveillance data in the DARPA Mind's Eye program, with hours of videos of challenging scenes. The results show that our system is able to track the people, detect and localize events, and discriminate between different behaviors, and it performs 3.4 times better than our previous system
Intersecting single-cell transcriptomics and genome-wide association studies identifies crucial cell populations and candidate genes for atherosclerosis
Genome-wide association studies (GWASs) have discovered hundreds of common genetic variants for atherosclerotic disease and cardiovascular risk factors. The translation of susceptibility loci into biological mechanisms and targets for drug discovery remains challenging. Intersecting genetic and gene expression data has led to the identification of candidate genes. However, previously studied tissues are often non-diseased and heterogeneous in cell composition, hindering accurate candidate prioritization. Therefore, we analysed single-cell transcriptomics from atherosclerotic plaques for cell-type-specific expression to identify atherosclerosis-associated candidate gene-cell pairs.\nWe applied gene-based analyses using GWAS summary statistics from 46 atherosclerotic and cardiovascular disease, risk factors, and other traits. We then intersected these candidates with single-cell RNA sequencing (scRNA-seq) data to identify genes specific for individual cell (sub)populations in atherosclerotic plaques. The coronary artery disease (CAD) loci demonstrated a prominent signal in plaque smooth muscle cells (SMCs) (SKI, KANK2, and SORT1) P-adj. = 0.0012, and endothelial cells (ECs) (SLC44A1, ATP2B1) P-adj. = 0.0011. Finally, we used liver-derived scRNA-seq data and showed hepatocyte-specific enrichment of genes involved in serum lipid levels.\nWe discovered novel and known gene-cell pairs pointing to new biological mechanisms of atherosclerotic disease. We highlight that loci associated with CAD reveal prominent association levels in mainly plaque SMC and EC populations. We present an intuitive single-cell transcriptomics-driven workflow rooted in human large-scale genetic studies to identify putative candidate genes and affected cells associated with cardiovascular traits. Collectively, our workflow allows for the identification of cell-specific targets relevant for atherosclerosis and can be universally applied to other complex genetic diseases and traits.Biopharmaceutic
Skeletal evidence of craft production from the Ch'iji Jawira site in Tiwanaku, Bolivia
The Tiwanaku culture in the Bolivian highlands was comprised of neighborhoods home to various groups laboring at differing jobs. Ch'iji Jawira, one site within this community, is described archaeologically as containing both a manufacturing center for pottery and a residential area home to these ceramic manufacturers. Prior bioarchaeological research has also noted that the people buried at the Ch'iji Jawira site show statistically significant differences in labor and activity from others who lived in the Tiwanaku capital. Using a life-history approach, this study explores the idea that Ch'iji Jawira was home to ceramic specialists by describing one individual from this community, a 30–39 year old female (CJ-35250). This person has evidence of degeneration associated with osteoarthritis in her arms, wrists, hands, fingers, lumbar spine, sacroiliac, hip, and feet. The bones of her wrists, hands, fingers, and feet also have extensive skeletal changes at tendon and muscle attachment areas. The pattern on her bones suggests she worked at crafting, especially tasks involving repetitive joint movement and heavy use of arm, hand, and foot musculature. From her burial location and grave goods, it may be that CJ-35250 was one of the earliest potters at this site
Quality of life in children with osteogenesis imperfecta treated with oral bisphosphonates (Olpadronate): a 2-year randomized placebo-controlled trial
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