3,098 research outputs found
Nazarbayev University multigrasp hand with bidirectional tendon actuation
Robotic hands are being used in various areas such as industrial automation, medical
robotics, and defense. In this work, we are presenting the Nazarbayev University Multigrasp Robot Hand
with an integrated RGB-Depth camera for intelligent object manipulation. The novelty ofthe project is seen
in the creation of an end effector system which obtains higher level autonomy from the base manipulator,
being able to recognize target objects, generate approach trajectories and apply corresponding grasping
patterns to capture the object
Effects of irrigation applied at different growth stages on chickpea yield
ArticleThis study was conducted over the experimental fields of Erciyes University in 2016
to investigate the effects of irrigations applied at different growth stages on chickpea yields. Experiments were conducted in randomized blocks design with 3 replications. There were 7 irrigation treatments as of I1: rainfed, I2: pre-bloom single irrigation, I3: single irrigation at the
beginning of blooming, I4: single irrigation at 50% pod set, I5: two irrigations at 50% bloom and 50% pod-set, I6: two irrigations at pre-bloom and 50% pod-set, I7: full irrigation. The amount of applied irrigation water varied between 85.6–323 mm. Plant water
consumptions varied between 262
– 569 mm. The greatest yield was obtained from I4 treatment with 273 kg da-1 and the lowest yield was obtained from I1
treatments with 146 kg da-1. It was
concluded for chickpea cultivation under deficit water resources conditions that water deficits may be applied at different growth
stages except for 50% pod-set period
Locomotion strategy selection for a legged wheeled hybrid quadruped using depth images
Three fundamental locomotion configurations recognized commonly are legged, wheeled,
and articulated mechanisms using which a mobile robot can navigate terrains. Hybrid configurations
enable execution of different locomotion types separately and in combinations. Such advantage usually
implies complexity and necessity in a robust supervisory controller capable of terrain recognition and
locomotion strategy selection. We developed the Nazarbayev University (NU) Hybrid Quadruped (Fig. 1)
- mobile robot with four legs and wheels. Project's major novelty is the implementation of the supervisory
controller which selects a locomotion mode associated with particular terrain types based on its terrain
recognizer input data
Inertial motion capture based teleoperation of a mobile robot manipulator with a multigrasp hand
Autonomous mobile robots are still not reliable enough for performing complex tasks
such as search and rescue, space or undersea exploration and explosive ordnance disposal. Human
intelligence is frequently employed for high-level robot decision making and control. Moreover, for most
of the cases low-weight and dexterous end-effectors are required for performing delicate tasks efficiently
Inertial motion capture based teleoperation of a mobile robot manipulator with a multigrasp hand
Autonomous mobile robots are still not reliable enough for performing complex tasks
such as search and rescue, space or undersea exploration and explosive ordnance disposal. Human
intelligence is frequently employed for high-level robot decision making and control. Moreover, for most
of the cases low-weight and dexterous end-effectors are required for performing delicate tasks efficiently
Towards Intelligent Lower Limb Prostheses with Activity Recognition
User’s volitional control of lower limb prostheses is still challenging task despite technological advancements. There is still a need for amputees to impose their will upon the prosthesis to drive in an accurate and interactive fashion. This study represents a brief review on control strategies using different sensor modalities for the purpose of phases/events detection and activity recognition. The preliminary work that is associated with middle-level control shows a simple and reliable method for event detection in real-time using a single inertial measurement unit. The outcome shows promising results
Competing Ultrafast Energy Relaxation Pathways in Photoexcited Graphene
For most optoelectronic applications of graphene a thorough understanding of
the processes that govern energy relaxation of photoexcited carriers is
essential. The ultrafast energy relaxation in graphene occurs through two
competing pathways: carrier-carrier scattering -- creating an elevated carrier
temperature -- and optical phonon emission. At present, it is not clear what
determines the dominating relaxation pathway. Here we reach a unifying picture
of the ultrafast energy relaxation by investigating the terahertz
photoconductivity, while varying the Fermi energy, photon energy, and fluence
over a wide range. We find that sufficiently low fluence ( 4
J/cm) in conjunction with sufficiently high Fermi energy (
0.1 eV) gives rise to energy relaxation that is dominated by carrier-carrier
scattering, which leads to efficient carrier heating. Upon increasing the
fluence or decreasing the Fermi energy, the carrier heating efficiency
decreases, presumably due to energy relaxation that becomes increasingly
dominated by phonon emission. Carrier heating through carrier-carrier
scattering accounts for the negative photoconductivity for doped graphene
observed at terahertz frequencies. We present a simple model that reproduces
the data for a wide range of Fermi levels and excitation energies, and allows
us to qualitatively assess how the branching ratio between the two distinct
relaxation pathways depends on excitation fluence and Fermi energy.Comment: Nano Letters 201
Carbonates from the ancient world's longest aqueduct:A testament of Byzantine water management
The fourth‐ and fifth‐century aqueduct system of Constantinople is, at 426 km, the longest water supply line of the ancient world. Carbonate deposits in the aqueduct system provide an archive of both archaeological developments and palaeo‐environmental conditions during the depositional period. The 246‐km‐long aqueduct line from the fourth century used springs from a small aquifer, whereas a 180‐km‐long fifth‐century extension to the west tapped a larger aquifer. Although historical records testify at least 700 years of aqueduct activity, carbonate deposits in the aqueduct system display less than 27 years of operation. This implies that the entire system must have been cleaned of carbonate, presumably during regular campaigns. A 50‐km‐long double‐aqueduct section in the central part of the system may have been a costly but practical solution to allow repairs and cleaning of the aqueducts of carbonate to ascertain a continuous water supply to the city. The fifth‐century channel was commonly contaminated with clay, caused by the nature of the aqueduct system and possible local damage to the channel. This clay‐rich water could have been one of the reasons for the construction of large reservoirs in Constantinople.
imageLeverhulme Trust
http://dx.doi.org/10.13039/501100000275Deutsche Forschungsgemeinschaft
http://dx.doi.org/10.13039/50110000165
Characterizing Heterogeneity in Neuroimaging, Cognition, Clinical Symptoms, and Genetics Among Patients With Late-Life Depression
Importance:
Late-life depression (LLD) is characterized by considerable heterogeneity in clinical manifestation. Unraveling such heterogeneity might aid in elucidating etiological mechanisms and support precision and individualized medicine.
Objective:
To cross-sectionally and longitudinally delineate disease-related heterogeneity in LLD associated with neuroanatomy, cognitive functioning, clinical symptoms, and genetic profiles.
Design, Setting, and Participants:
The Imaging-Based Coordinate System for Aging and Neurodegenerative Diseases (iSTAGING) study is an international multicenter consortium investigating brain aging in pooled and harmonized data from 13 studies with more than 35 000 participants, including a subset of individuals with major depressive disorder. Multimodal data from a multicenter sample (N = 996), including neuroimaging, neurocognitive assessments, and genetics, were analyzed in this study. A semisupervised clustering method (heterogeneity through discriminative analysis) was applied to regional gray matter (GM) brain volumes to derive dimensional representations. Data were collected from July 2017 to July 2020 and analyzed from July 2020 to December 2021.
Main Outcomes and Measures:
Two dimensions were identified to delineate LLD-associated heterogeneity in voxelwise GM maps, white matter (WM) fractional anisotropy, neurocognitive functioning, clinical phenotype, and genetics.
Results:
A total of 501 participants with LLD (mean [SD] age, 67.39 [5.56] years; 332 women) and 495 healthy control individuals (mean [SD] age, 66.53 [5.16] years; 333 women) were included. Patients in dimension 1 demonstrated relatively preserved brain anatomy without WM disruptions relative to healthy control individuals. In contrast, patients in dimension 2 showed widespread brain atrophy and WM integrity disruptions, along with cognitive impairment and higher depression severity. Moreover, 1 de novo independent genetic variant (rs13120336; chromosome: 4, 186387714; minor allele, G) was significantly associated with dimension 1 (odds ratio, 2.35; SE, 0.15; P = 3.14 ×10⁸) but not with dimension 2. The 2 dimensions demonstrated significant single-nucleotide variant–based heritability of 18% to 27% within the general population (N = 12 518 in UK Biobank). In a subset of individuals having longitudinal measurements, those in dimension 2 experienced a more rapid longitudinal change in GM and brain age (Cohen ƒ² = 0.03; P = .02) and were more likely to progress to Alzheimer disease (Cohen ƒ² = 0.03; P = .03) compared with those in dimension 1 (N = 1431 participants and 7224 scans from the Alzheimer’s Disease Neuroimaging Initiative [ADNI], Baltimore Longitudinal Study of Aging [BLSA], and Biomarkers for Older Controls at Risk for Dementia [BIOCARD] data sets).
Conclusions and Relevance:
This study characterized heterogeneity in LLD into 2 dimensions with distinct neuroanatomical, cognitive, clinical, and genetic profiles. This dimensional approach provides a potential mechanism for investigating the heterogeneity of LLD and the relevance of the latent dimensions to possible disease mechanisms, clinical outcomes, and responses to interventions
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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