248 research outputs found

    DEVELOPMENT OF A TRIAXIAL FORCE PLATFORM FOR THE MEASUREMENT OF FORCE AT A BICYCLE PEDAL

    Get PDF
    The main purpose of this work is to present the methodology used to develop a triaxial force platform for the use at a pedal bicycle; this platform is based on the flexion of beams where strain gages are bonded for the measurements of force components FX, FY and FZ, as well as the force moments MX and MY. The theoretical analysis of this force platform was realized by the Finite Element method, with the simulation of 384 combinations of static loads (force and moments) at different directions. Deformation data numerically obtained is related to the position were sensors will be placed. Output signals obtained were numerically organized and graphically analyzed, in order to show the mathematical relation between force and strain, which is used to generate a "calibration matrix", free of mechanical coupling which usually appears in multiaxis systems. At last, a test was made, simulating an input load, and the output signal obtained was practically equal

    Pengaruh Kadar Lempung dengan Kadar Air di Atas OMC terhadap Nilai CBR dengan dan tanpa Rendaman pada Tanah Lempung Organik

    Full text link
    Strength and durability of road pavement depend on engineering properties of subgrade. However, soils used as subgrade may not satisfy the required quality. Peat or organic soils is not to advantage of construction because bearing capacity or value of peat soil's CBR is low. This paper intends to find out more about CBR value of organic soils on OMC and saturated condition . This research investigated the changes of CBR value with moisture content in the range of OMC to saturated. And influenced percentage varied of peat in mixture organic soils (clay and peat). The result of this study showed that for increasing of peat content reduce CBR values at OMC condition. CBR value in addition 10% of peat decreased CBR significantly to 2,88 % as compared to original soil (clay) is about 23,88%. And when compaction of soils with water content above OMC, incresing content of water reduce value of CBR

    Comparison of two alternatives of combined drying to process blueberries (O'Neal): evaluation of the final quality

    Get PDF
    In this work, we examined and compared two combined alternatives for the drying of blueberries (O´Neal). Pretreatments of osmotic dehydration (60°Brix sucrose solution, at 40°C for 6h) and hot air drying (60°C, 2.5 m/s for 90 min) were performed to reach the same water content. Pretreated blueberries were then dried by microwave at different microwave output power values: 562.5W, 622.5W and 750W. The combined drying processes were also compared with hot air drying alone (control). The effects of the processes over blueberries were studied in terms of decrease in water content, drying rate, mechanical properties (firmness and stiffness), optical properties (L*, a* and hue angle (h)), antioxidant capacity and rehydration capacity. The hot air-microwave drying decreased the process time and presented a high drying rate compared with the osmotic dehydration-microwave processes and the control drying. In terms of quality, the antioxidant and rehydration capacities were the most affected. The results showed that the best drying method to obtain the desired final product was the hot air-microwave drying (750W).Fil: Rodriguez, A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones En Criotecnología de Alimentos (i); Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; ArgentinaFil: Zaro, Maria Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones En Criotecnología de Alimentos (i); Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; ArgentinaFil: Lemoine, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones En Criotecnología de Alimentos (i); Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; ArgentinaFil: Mascheroni, Rodolfo Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones En Criotecnología de Alimentos (i); Argentina. Universidad Nacional de La Plata. Facultad de Ingenieria; Argentin

    Deciphering species-specific pollen tube guidance in Solanum

    Get PDF
    Small, secreted cysteine-rich proteins (CRPs)combine a highly stable cysteine spacing,ensuring conservation of their 3D structure andfunction, and hypervariable inter-cysteine blocks, allowing quick evolution of specific recognition domains. Interestingly, several CRPs were shown to control key pollen-pistil interactions in aspecies-specific way. The most emblematicexample is perhaps the LURE defensin-likefamily, controlling directional guidance of pollentubes (PTs) in Torenia and Arabidopsis.We chose wild potatoes (Solanum sect. Petota) asa case study to investigate the impact of rapidCRP divergence in plant speciation. Gathering ~200 close species with overlapping distribution areas, this taxon indeed exhibits strong reproductive isolation. Lab-on-a-chipmicrofluidic experiments carried out on 4 species show that species-preferential PT attraction is a key factor in this isolation. We suspect polymorphic CRPs to control this attraction. High-throughput sequencing technologies were applied to profile the ovule secretome as well as the reproductive transcriptomes of our 4 speciesof interest. To screen out candidate genes, we developped KAPPA, a sequence search algorithm specifically dedicated to CRPs, and obtained a set of 32 defensin-like groups expressed in ovules. Five promising chemoattractant candidates exhibiting (i) ovule-specific expression, (ii) down-regulation in guidance-defective ovules, and (iii) interspecific divergence were selectedfor further characterization. They are currently being investigated with on-gel assays and specific microfluidic devices tailored for Solanum PTs. This study will lead to a better understanding of CRP-mediated PT chemoattraction as one of the major species-specificity checkpoints that mustbe unlocked by pollen tubes in the pistil.Fil: Joly, V.. Institut de Recherche En Biologie Végétale; CanadáFil: Viallet, C.. Institut de Recherche En Biologie Végétale; CanadáFil: Liu, Y.. Institut de Recherche En Biologie Végétale; CanadáFil: Zaro, A.. Universidad de Barcelona; EspañaFil: Ceriotti, Luis Federico. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Biología Agrícola de Mendoza. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de Biología Agrícola de Mendoza; ArgentinaFil: Matton, D. P.. Institut de Recherche En Biologie Végétale; CanadáEastern Regional MeetingMontrealCanadáCanadian Society of Plant BiologistsMcGill Universit

    Thermographic evaluation of hind paw skin temperature and functional recovery of locomotion after sciatic nerve crush in rats

    Get PDF
    INTRODUCTION: Peripheral nerves are often damaged by direct mechanical injury, diseases, and tumors. The peripheral nerve injuries that result from these conditions can lead to a partial or complete loss of motor, sensory, and autonomic functions, which in turn are related to changes in skin temperature, in the involved segments of the body. The aim of this study was to evaluate the changes in hind paw skin temperature after sciatic nerve crush in rats in an attempt to determine whether changes in skin temperature correlate with the functional recovery of locomotion. METHODS: Wistar rats were divided into three groups: control (n = 7), sham (n = 25), and crush (n = 25). All groups were subjected to thermographic, functional, and histological assessments. RESULTS: DT in the crush group was different from the control and sham groups at the 1st, 3rd and 7rd postoperative days (p,0.05). The functional recovery from the crush group returned to normal values between the 3rd and 4th week post-injury, and morphological analysis of the nerve revealed incomplete regeneration at the 4th week after injury. DISCUSSION: This study is the first demonstration that sciatic nerve crush in rats induces an increase in hind paw skin temperature and that skin temperature changes do not correlate closely with functional recovery

    Whole Body Vibration at Different Exposure Frequencies: Infrared Thermography and Physiological Effects

    Get PDF
    The aim of this study was to investigate the effects of whole body vibration (WBV) on physiological parameters, cutaneous temperature, tactile sensitivity, and balance. Twenty-four healthy adults (25.3±2.6 years) participated in four WBV sessions. They spent 15 minutes on a vibration platform in the vertical mode at four different frequencies (31, 35, 40, and 44 Hz) with 1 mm of amplitude. All variables were measured before and after WBV exposure. Pressure sensation in five anatomical regions and both feet was determined using Von Frey monofilaments. Postural sway was measured using a force plate. Cutaneous temperature was obtained with an infrared camera. WBV influences the discharge of the skin touch-pressure receptors, decreasing sensitivity at all measured frequencies and foot regions (P≤0.05). Regarding balance, no differences were found after 20 minutes of WBV at frequencies of 31 and 35 Hz. At 40 and 44 Hz, participants showed higher anterior-posterior center of pressure (COP) velocity and length. The cutaneous temperature of the lower limbs decreased during and 10 minutes after WBV. WBV decreases touch-pressure sensitivity at all measured frequencies 10 min after exposure. This may be related to the impaired balance at higher frequencies since these variables have a role in maintaining postural stability. Vasoconstriction might explain the decreased lower limb temperature

    Community-curated and standardised metadata of published ancient metagenomic samples with AncientMetagenomeDir

    Get PDF
    Ancient DNA and RNA are valuable data sources for a wide range of disciplines. Within the field of ancient metagenomics, the number of published genetic datasets has risen dramatically in recent years, and tracking this data for reuse is particularly important for large-scale ecological and evolutionary studies of individual microbial taxa, microbial communities, and metagenomic assemblages. AncientMetagenomeDir (archived at https://doi.org/10.5281/zenodo.3980833) is a collection of indices of published genetic data deriving from ancient microbial samples that provides basic, standardised metadata and accession numbers to allow rapid data retrieval from online repositories. These collections are community-curated and span multiple sub-disciplines in order to ensure adequate breadth and consensus in metadata definitions, as well as longevity of the database. Internal guidelines and automated checks to facilitate compatibility with established sequence-read archives and term-ontologies ensure consistency and interoperability for future meta-analyses. This collection will also assist in standardising metadata reporting for future ancient metagenomic studies.Competing Interest StatementThe authors have declared no competing interest.Background & Summary Methods - Repository Structure - Data Acquisition - Data Validation Data Records Technical Validation Usage Note

    Model-independent extraction of ∣Vtq∣|V_{tq}| matrix elements from top-quark measurements at hadron colliders

    Full text link
    Current methods to extract the quark-mixing matrix element ∣Vtb∣|V_{tb}| from single-top production measurements assume that ∣Vtb∣≫∣Vtd∣,∣Vts∣|V_{tb}|\gg |V_{td}|, |V_{ts}|: top quarks decay into bb quarks with 100% branching fraction, s-channel single-top production is always accompanied by a bb quark and initial-state contributions from dd and ss quarks in the tt-channel production of single top quarks are neglected. Triggered by a recent measurement of the ratio R=∣Vtb∣2∣Vtd∣2+∣Vts∣2+∣Vtb∣2=0.90±0.04R=\frac{|V_{tb}|^{2}}{|V_{td}|^{2}+|V_{ts}|^{2}+|V_{tb}|^{2}}=0.90 \pm 0.04 performed by the D0 collaboration, we consider a ∣Vtb∣|V_{tb}| extraction method that takes into account non zero d- and s-quark contributions both in production and decay. We propose a strategy that allows to extract consistently and in a model-independent way the quark mixing matrix elements ∣Vtd∣|V_{td}|, ∣Vts∣|V_{ts}|, and ∣Vtb∣|V_{tb}| from the measurement of RR and from single-top measured event yields. As an illustration, we apply our method to the Tevatron data using a CDF analysis of the measured single-top event yield with two jets in the final state one of which is identified as a bb-quark jet. We constrain the ∣Vtq∣|V_{tq}| matrix elements within a four-generation scenario by combining the results with those obtained from direct measurements in flavor physics and determine the preferred range for the top-quark decay width within different scenarios.Comment: 36 pages, 17 figure
    • …
    corecore