4,263 research outputs found
AI-based smart sensing and AR for gait rehabilitation assessment
Health monitoring is crucial in hospitals and rehabilitation centers. Challenges can affect the reliability and accuracy of health data. Human error, patient compliance concerns, time, money, technology, and environmental factors might cause these issues. In order to improve patient care, healthcare providers must address these challenges. We propose a non-intrusive smart sensing system that uses a SensFloor smart carpet and an inertial measurement unit (IMU) wearable sensor on the user’s back to monitor position and gait characteristics. Furthermore, we implemented machine learning (ML) algorithms to analyze the data collected from the SensFloor and IMU sensors. The system generates real-time data that are stored in the cloud and are accessible to physical therapists and patients. Additionally, the system’s real-time dashboards provide a comprehensive analysis of the user’s gait and balance, enabling personalized training plans with tailored exercises and better rehabilitation outcomes. Using non-invasive smart sensing technology, our proposed solution enables healthcare facilities to monitor patients’ health and enhance their physical rehabilitation plans.info:eu-repo/semantics/publishedVersio
Kinematics of the ionized-to-neutral interfaces in Monoceros R2
Context. Monoceros R2 (Mon R2), at a distance of 830 pc, is the only
ultra-compact H ii region (UC H ii) where its associated photon-dominated
region (PDR) can be resolved with the Herschel Space Observatory. Aims. Our aim
is to investigate observationally the kinematical patterns in the interface
regions (i.e., the transition from atomic to molecular gas) associated with Mon
R2. Methods. We used the HIFI instrument onboard Herschel to observe the line
profiles of the reactive ions CH+, OH+ and H2O+ toward different positions in
Mon R2. We derive the column density of these molecules and compare them with
gas-phase chemistry models. Results. The reactive ion CH+ is detected both in
emission (at central and red-shifted velocities) and in absorption (at
blue-shifted velocities). OH+ is detected in absorption at both blue- and
red-shifted velocities, with similar column densities. H2O+ is not detected at
any of the positions, down to a rms of 40 mK toward the molecular peak. At this
position, we find that the OH+ absorption originates in a mainly atomic medium,
and therefore is associated with the most exposed layers of the PDR. These
results are consistent with the predictions from photo-chemical models. The
line profiles are consistent with the atomic gas being entrained in the ionized
gas flow along the walls of the cavity of the H ii region. Based on this
evidence, we are able to propose a new geometrical model for this region.
Conclusions. The kinematical patterns of the OH+ and CH+ absorption indicate
the existence of a layer of mainly atomic gas for which we have derived, for
the first time, some physical parameters and its dynamics.Comment: 6 pages, 5 figures. Accepted for publication in A&
Pearling: stroke segmentation with crusted pearl strings
We introduce a novel segmentation technique, called Pearling, for the semi-automatic extraction of idealized models of networks of strokes (variable width curves) in images. These networks may for example represent roads in an aerial photograph, vessels in a medical scan, or strokes in a drawing. The operator seeds the process by selecting representative areas of good (stroke interior) and bad colors. Then, the operator may either provide a rough trace through a particular path in the stroke graph or simply pick a starting point (seed) on a stroke and a direction of growth. Pearling computes in realtime the centerlines of the strokes, the bifurcations, and the thickness function along each stroke, hence producing a purified medial axis transform of a desired portion of the stroke graph. No prior segmentation or thresholding is required. Simple gestures may be used to trim or extend the selection or to add branches. The realtime performance and reliability of Pearling results from a novel disk-sampling approach, which traces the strokes by optimizing the positions and radii of a discrete series of disks (pearls) along the stroke. A continuous model is defined through subdivision. By design, the idealized pearl string model is slightly wider than necessary to ensure that it contains the stroke boundary. A narrower core model that fits inside the stroke is computed simultaneously. The difference between the pearl string and its core contains the boundary of the stroke and may be used to capture, compress, visualize, or analyze the raw image data along the stroke boundary
Fabrication and characterization of Cu reinforced with Y-enriched particles following a novel powder metallurgy route
Dispersion strengthened copper alloys have been produced following an innovative powder metallurgy route. Copper and yttrium acetate powders have been mechanically alloyed and posteriorly thermal treated at 923 K for 3 h and 15 h under a hydrogen atmosphere in order to transform the yttrium acetate into Y2O3. Subsequently, the powders were consolidated by hot isostatic pressing. It has been concluded that the duration of the thermal treatment of the powder is a determining factor in the degree of densification of the alloy. The study of the microstructure by Scanning Electron Microscopy and Electron Backscatter Diffraction has revealed the presence of micrometer and submicrometer grains and nanometric Y-O enriched Cu particles embedded in the copper matrix, the mean grain size being smaller for the sample produced from the powder thermal treated for 15 h. Transmission Electron Microscopy investigations concluded that the nanoparticles exhibit a spherical shape with a size up to 25 nm and correspond to monoclinic Y2O3. Annealing twins have been also observed, especially in the material produced from thermal treated powder for longer.
The mechanical properties have been inferred from Vickers microhardness measurements and compression tests. Below 473 K the yield strengths of the produced materials are greater than that of pure copper and above 473 K are close to them. From the study of the thermal properties of the densest material it has been found that its thermal conductivity remains nearly constant in the temperature range 300–773 K, and its value is around 85% the thermal conductivity of CuCrZr, the reference material for ITER.The present work has been supported by the Agencia Estatal de Investigación (PID2019-105325RB-C33 / AEI / 10.13039/501100011033) and by the Regional Government of Madrid through the program TECHNOFUSIÓN(III)CM (S2018/EMT-4437). The support of the Regional Government of Madrid through the multi-annual agreement with UC3M ("Excelencia para el Profesorado Universitario"- EPUC3M14) - Fifth regional research plan 2016-2020 is acknowledge
The first CO+ image: Probing the HI/H2 layer around the ultracompact HII region Mon R2
The CO+ reactive ion is thought to be a tracer of the boundary between a HII
region and the hot molecular gas. In this study, we present the spatial
distribution of the CO+ rotational emission toward the Mon R2 star-forming
region. The CO+ emission presents a clumpy ring-like morphology, arising from a
narrow dense layer around the HII region. We compare the CO+ distribution with
other species present in photon-dominated regions (PDR), such as [CII] 158 mm,
H2 S(3) rotational line at 9.3 mm, polycyclic aromatic hydrocarbons (PAHs) and
HCO+. We find that the CO+ emission is spatially coincident with the PAHs and
[CII] emission. This confirms that the CO+ emission arises from a narrow dense
layer of the HI/H2 interface. We have determined the CO+ fractional abundance,
relative to C+ toward three positions. The abundances range from 0.1 to
1.9x10^(-10) and are in good agreement with previous chemical model, which
predicts that the production of CO+ in PDRs only occurs in dense regions with
high UV fields. The CO+ linewidth is larger than those found in molecular gas
tracers, and their central velocity are blue-shifted with respect to the
molecular gas velocity. We interpret this as a hint that the CO+ is probing
photo-evaporating clump surfaces.Comment: The main text has 4 pages, 2 pages of Appendix, 4 figures, 1 table.
Accepted for publication in Astronomy and Astrophysics letter
Microstructure and mechanical properties of hot rolled ODS copper
Dispersion strengthened copper alloys have been produced by following a powder metallurgy route that have consisted of milling copper and yttrium acetate powders in a planetary ball milling and subsequently sintering by hot isostatic pressing (HIP). In order to increase the degree of densification of the materials, they were subjected to a thermal treatment in vacuum and to a hot rolling process at 1173 K. The decomposition of the yttrium acetate during the thermal treatments resulted in the formation of voids, with a loss of densification that could not be satisfactorily improved with the hot rolling processing. The microstructure and the mechanical and thermal properties of the alloys were analyzed by scanning electron microscopy, electron backscattering diffraction, micro and nanohardness measurements, and compression tests and thermal conductivity measurements, both in the range 300–780 K. The best mechanical properties were obtained for the as-HIP material, with a mean grain size of 0.3 ± 0.3 μm and a yield strength value at room temperature of 520 MPa. In contrast, the material with the highest thermal conductivity for the entire range of temperature was found to be the alloy thermal treated in vacuum at 1273 K and later subjected to the hot rolling processing. The different microstructural characteristics of the alloys such as grain size, defects present in the grains and size of voids seems to be responsible of the differences on their thermal conductivity values.The present work has been supported by the Ministerio de Economía y Competitividad of Spain (ENE2015-70300-C3-2-R MINECO/FEDER) and by the Regional Government of Madrid through the program TECHNOFUSIÓN(III)CM (S2018/EMT-4437)
Development of a three-dimensional cell culture system based on microfluidics for nuclear magnetic resonance and optical monitoring.
A new microfluidic cell culture device compatible with real-time nuclear magnetic resonance (NMR) is presented here. The intended application is the long-term monitoring of 3D cell cultures by several techniques. The system has been designed to fit inside commercially available NMR equipment to obtain maximum readout resolution when working with small samples. Moreover, the microfluidic device integrates a fibre-optic-based sensor to monitor parameters such as oxygen, pH, or temperature during NMR monitoring, and it also allows the use of optical microscopy techniques such as confocal fluorescence microscopy. This manuscript reports the initial trials culturing neurospheres inside the microchamber of this device and the preliminary images and spatially localised spectra obtained by NMR. The images show the presence of a necrotic area in the interior of the neurospheres, as is frequently observed in histological preparations; this phenomenon appears whenever the distance between the cells and fresh nutrients impairs the diffusion of oxygen. Moreover, the spectra acquired in a volume of 8 nl inside the neurosphereshow an accumulation of lactate and lipids, which are indicative of anoxic condi-tions. Additionally, a basis for general temperature control and monitoring and a graphical control software have been developed and are also described. The complete platform will allow biomedical assays of therapeutic agents to be performed in the early phases of therapeutic development. Thus, small quantities of drugs or advanced nanodevices may be studied long-term under simulated living conditions that mimic the flow and distribution of nutrient
Gestión de adaptación al cambio climático en la actividad lechera: un aporte reflexivo: Gestão de adaptação às mudanças climáticas na atividade leiteira: uma contribuição reflexiva
Los sistemas de producción lechera se enfrentan al desafío de producir combinando la rentabilidad con la protección al medio ambiente, la salud humana y el bienestar animal; y además, satisfacer las demandas de los transformadores y de los consumidores. En estas condiciones, los productores de leche han venido tomando una serie de medidas para adaptarse al cambio climático y producir en armonía con el medio ambiente. Este asunto se convirtió en prioridad nacional y con el apoyo de varias instituciones y organizaciones, públicas y privadas, ha ocurrido que en Costa Rica exista una Estrategia Nacional de Ganadería Baja en Carbono (EGBC), un Programa de Investigación y Transferencia de Tecnología Agropecuaria de Ganadería (PITTA-Ganadería) y un NAMA-Ganadería (Acciones de Mitigación Nacionalmente Apropiadas, NAMA por sus siglas en inglés). Todos estos instrumentos son soluciones viables con las situaciones productivas y el bienestar social de una población importante de pequeños productores que dependen de esta actividad
Factors that influence the SMEs performance: a qualitative perspective of Costa Rican entrepreneurs
In Costa Rica, as in the rest of the Latin American countries, a significant number of SMEs enter into operations every year and their performance is influenced by several factors. This study focuses on identifying the facilitators and barriers that influence Costa Rican SMEs performance. A qualitative research was carried out through sessions, mini group sessions, and in-depth interviews, separating the subjects into three interest groups. The motivations to start up and the factors triggering the closure as well as those that led to success were identified from the entrepreneur’s perspective. Costa Rican SMEs’ performance is neither influenced by factors related to the entrepreneur, economy, politics, society nor by personal factors such as education and training, personal attitudes or an entrepreneurial family background
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