546 research outputs found
Geometrical control of the magnetization direction in high aspect-ratio PdNi ferromagnetic nano-electrodes
We present a study of electron-beam evaporated Pd0.4Ni0.6 alloy thin films by
means of ferromagnetic resonance measurements on extended films of varying
thickness and anisotropic magnetoresistance measurements of lithographically
patterned high aspect-ratio ferromagnetic electrodes, respectively. The results
reveal that the direction of the magnetization strongly depends on the
electrode lateral dimensions, transitioning from in-plane magnetization for
extended films to out-of-the-plane magnetization for electrode widths below 2-3
microns, reaching 58 degrees off-plane for 100 nm-wide nanoelectrodes.Comment: Preprint submitted to PRB (14 pages, 4 figures
Combining a hybrid robotic system with a bain-machine interface for the rehabilitation of reaching movements: A case study with a stroke patient
Reaching and grasping are two of the most affected functions after stroke. Hybrid rehabilitation systems combining Functional Electrical Stimulation with Robotic devices have been proposed in the literature to improve rehabilitation outcomes. In this work, we present the combined use of a hybrid robotic system with an EEG-based Brain-Machine Interface to detect the user's movement intentions to trigger the assistance. The platform has been tested in a single session with a stroke patient. The results show how the patient could successfully interact with the BMI and command the assistance of the hybrid system with low latencies. Also, the Feedback Error Learning controller implemented in this system could adjust the required FES intensity to perform the task
On-chip Integration of High-Frequency Electron Paramagnetic Resonance Spectroscopy and Hall-Effect Magnetometry
A sensor that integrates high sensitivity micro-Hall effect magnetometry and
high-frequency electron paramagnetic resonance spectroscopy capabilities on a
single semiconductor chip is presented. The Hall-effect magnetometer was
fabricated from a two dimensional electron gas GaAs/AlGaAs heterostructure in
the form of a cross, with a 50x50 um2 sensing area. A high-frequency microstrip
resonator is coupled with two small gaps to a transmission line with a 50 Ohms
impedance. Different resonator lengths are used to obtain quasi-TEM fundamental
resonant modes in the frequency range 10-30 GHz. The resonator is positioned on
top of the active area of the Hall-effect magnetometer, where the magnetic
field of the fundamental mode is largest, thus optimizing the conversion of
microwave power into magnetic field at the sample position. The two gaps
coupling the resonator and transmission lines are engineered differently. The
gap to the microwave source is designed to optimize the loaded quality factor
of the resonator (Q = 150) while the gap for the transmitted signal is larger.
This latter gap minimizes losses and prevents distortion of the resonance while
enabling measurement of the transmitted signal. The large filling factor of the
resonator permits sensitivities comparable to that of high-quality factor
resonant cavities. The integrated sensor enables measurement of the
magnetization response of micron scale samples upon application of microwave
fields. In particular, the combined measurement of the magnetization change and
the microwave power under cw microwave irradiation of single crystal of
molecular magnets is used to determine of the energy relaxation time of the
molecular spin states. In addition, real time measurements of the magnetization
dynamics upon application of fast microwave pulses are demonstratedComment: Submitted to Review of Scientific Instrument
Electroencephalography-guided upper-limb hybrid robotic platform to modulate cortical excitability
This study present an intervention combining an electroencephalography-based brain computer interface with a hybrid robotic system for the modulation of the cortical excitability (plasticity). Plasticity is intended to be elicited through the association of the voluntary motor-related cortical processes with the hybrid assistance during the execution of reaching movement. The cortical excitability was assessed before and after the intervention measuring the peak-to-peak amplitude of the Motor Evoked Potentials (MEPs) induced through transcranial magnetic stimulation pulses. Five healthy subjects participated in the experiments. Results showed an overall and distributed increase in the cortical excitability as a result of the proposed intervention
Three-Dimensional Spectral-Domain Optical Coherence Tomography Data Analysis for Glaucoma Detection
Purpose: To develop a new three-dimensional (3D) spectral-domain optical coherence tomography (SD-OCT) data analysis method using a machine learning technique based on variable-size super pixel segmentation that efficiently utilizes full 3D dataset to improve the discrimination between early glaucomatous and healthy eyes. Methods: 192 eyes of 96 subjects (44 healthy, 59 glaucoma suspect and 89 glaucomatous eyes) were scanned with SD-OCT. Each SD-OCT cube dataset was first converted into 2D feature map based on retinal nerve fiber layer (RNFL) segmentation and then divided into various number of super pixels. Unlike the conventional super pixel having a fixed number of points, this newly developed variable-size super pixel is defined as a cluster of homogeneous adjacent pixels with variable size, shape and number. Features of super pixel map were extracted and used as inputs to machine classifier (LogitBoost adaptive boosting) to automatically identify diseased eyes. For discriminating performance assessment, area under the curve (AUC) of the receiver operating characteristics of the machine classifier outputs were compared with the conventional circumpapillary RNFL (cpRNFL) thickness measurements. Results: The super pixel analysis showed statistically significantly higher AUC than the cpRNFL (0.855 vs. 0.707, respectively, p = 0.031, Jackknife test) when glaucoma suspects were discriminated from healthy, while no significant difference was found when confirmed glaucoma eyes were discriminated from healthy eyes. Conclusions: A novel 3D OCT analysis technique performed at least as well as the cpRNFL in glaucoma discrimination and even better at glaucoma suspect discrimination. This new method has the potential to improve early detection of glaucomatous damage. © 2013 Xu et al
Benchmarking Bipedal Locomotion: A Unified Scheme for Humanoids, Wearable Robots, and Humans
In the field of robotics, there is a growing awareness of the importance of benchmarking [1], [2]. Benchmarking not only allows the assessment and comparison of the performance of different technologies but also defines and supports the standardization and regulation processes during their introduction to the market. Its importance has been recently emphasized by the adoption of the technology readiness levels (TRLs) in the Horizon 2020 information and communication technologies by the European Union as an important guideline to assess when a technology can shift from one TRL to the other. The objective of this article is to define the basis of a benchmarking scheme for the assessment of bipedal locomotion that could be applied and shared across different research communities.European Commission Seventh Framework Program, and COS
Alcopops Disproportionately Consumed by Minors in Sexual Assault Cases
Alcohol is present in a large proportion of sexual assault cases. However, research largely overlooks the role that providing alcoholic beverages – particularly those with high-alcohol- content and/or whose flavors mask the taste of alcohol – may have in making young people more vulnerable to being assaulted. This research is especially important given the rise in the availability of sugar-sweetened alcopops and their high-alcohol-content counterparts “supersized alcopops,” which contain up to 5.5 standard alcoholic drinks. In the current study, we examined whether alcopops and supersized alcopops, relative to beer, were involved in disproportionately more sexual assault cases involving victims who were minors (\u3c 18 years old) rather than adults. In this secondary data analysis, we used Nexis Uni to search legal documents for the brands of supersized alcopop (Four Loko), alcopop (Smirnoff Ice), and beer (Bud Light) most commonly consumed by underage drinkers. Inclusion criteria were U.S. sexual assault cases occurring from 2010 to 2019 and involving victims who consumed one of these three alcohol brands. Two researchers coded information from the case facts, compared coding, and reaching consensus. Thirty-six cases were included for analyses. Compared to victims of sexual assault who consumed beer, victims who consumed supersized alcopops or alcopops were significantly more likely to be minors. Similar results were observed after adjusting for the victim being given the alcohol by the perpetrator, which was strongly associated with the victim being a minor. This study provides initial evidence that sexual assault perpetrators may disproportionately use alcopops and supersized alcopops for the sexual victimization of minors
Optimization of the design of OMNIS, the observatory of multiflavor neutrinos from supernovae
A Monte Carlo code has been developed to simulate the operation of the
planned detectors in OMNIS, a supernova neutrino observatory. OMNIS will detect
neutrinos originating from a core collapse supernova by the detection of
spalled neutrons from Pb- or Fe-nuclei. This might be accomplished using
Gd-loaded liquid scintillator. Results for the optimum configuration for such
modules with respect to both neutron detection efficiency and cost efficiency
are presented. Careful consideration has been given to the expected levels of
radioactive backgrounds and their effects. The results show that the amount of
data to be processed by a software trigger can be reduced to the <10kHz region
and a neutron, once produced in the detector, can be detected and identified
with an efficiency of >30%.Comment: Elsevier preprint; 29 pages, 23 figure
Living at Higher Altitude and Incidence of Overweight/Obesity: Prospective Analysis of the SUN Cohort
BACKGROUND:
Residence at high altitude has been associated with lower obesity rates probably due to hypoxia conditions. However, there is no evidence of this association in a free-living population.
OBJECTIVES:
We assessed the association between the altitude where each participant of a Spanish cohort (the SUN Project) was living and the incidence of overweight/obesity.
METHODS:
The SUN Project is a dynamic, prospective, multipurpose cohort of Spanish university graduates with a retention rate of 89%. We included in the analysis 9 365 participants free of overweight/obesity at baseline. At the baseline questionnaire, participants reported their postal code and the time they had been living in their city/village. We imputed the altitude of each postal code according to the data of the Spanish National Cartographic Institute and categorized participants in tertiles. We used Cox regression models to adjust for potential confounding variables.
RESULTS:
During a median follow-up of 10 years, we identified 2 156 incident cases of overweight/obesity. After adjusting for sex, age, time of residence at current city, baseline body mass index, physical activity, sedentarism and years of education (≤ 3 years, ≥ 4 years, Master/PhD), those participants in the third tertile (>456 m) exhibited a statistically significant 14% reduction in the risk of developing overweight/obesity in comparison to those in the first tertile (<124 m) (adjusted HR = 0.86; 95% CI: 0.77, 0.96).
CONCLUSIONS:
Living in cities of higher altitude was inversely associated with the risk of developing overweight/obesity in a cohort of Spanish university graduates
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