Bed Movement Research Articles

Development of an external system for monitoring the couch speed in radiotherapy using continuous bed movement.

Total body irradiation before bone marrow transplantation for hematological malignancies using Radixact, a high-precision radiotherapy machine, can potentially reduce side effects and the risk of secondary malignancies. However, stable control of couch speed is critical, and direct assessment methods outlined in quality assurance guidelines are lacking. This study aims to develop a real-time couch speed verification system for the Radixact. The developed system used a linear encoder to measure couch speed directly. Accuracy was verified via a linear stage, comparing measurements with a laser distance sensor. After placing a phantom simulating the human body on the Radixact couch, the couch speed was verified using predefined speed plans. Operating the linear stage at 0.1, 0.5, and 1.0mm/s revealed that the maximum position error of the developed verification system compared to the laser distance sensor was nearly equivalent to the distance resolution of the system (0.05mm/pulse), with negligible average speed error. When the Radixact couch operated at 0.1, 0.5, and 1.0mm/s, the values obtained by the verification system agreed with the theoretical values within the sampling period (0.01s) and distance resolution (0.05mm). The verification system developed provides real-time monitoring of the speed of the Radixact table, ensuring treatment effectiveness and patient safety. It would guarantee the couch speed's soundness and contribute to the "visualization" of safety.

Stability of granular media impacts morphological characteristics under different impact conditions

Abstract In planetary surfaces, oblique impact events are commonplace, and their study holds significant importance for understanding planetary impact processes and aiding in the design of landers and impactors. Current research predominantly focuses on simplified models to study the force and motion under vertical impact craters in terms of scale and impact loading. For oblique impacts, investigations have primarily concentrated on the final crater shape. However, the specific influence of impact load motion on particle bed movement and the precise impact angle’s effect on the ultimate crater shape during the impact process remain unclear. In this study, we used a custom-built oblique impact experimental setup to analyze changes in the velocity field of the particle bed and the horizontal movement of the impact load. Using quasi-static region to assess ellipticity, we aimed to reveal the state of particle movement during oblique impacts and explore the impact of impact angles and energies on crater formation. The results indicate that under large impact angles, the obliquely acquired kinetic energy is minimal, leading to a predominant static point source movement of the particle bed. At higher energy levels, the impact load primarily excavates downward, resulting in the formation of circular impact craters. These findings underscore the sensitivity of particle bed motion to impact angles, making it a crucial metric for assessing the impact of oblique angles on final crater morphology.

Potato processing: phenomenology and influence of vibration on bed movement

The configuration of the vibro-spouted bed dryer resembles that of a conventional spouted bed, but the circulation of the particles is controlled by a vertical imposed. As consequence, all the bed flows in a dense phase regime and the air velocity inside the bed is defined according to drying requirements alone. A dryer used in this study consists of a cylindrical chamber with a conical bottom (diameter 145 mm, height 390 mm) equipped with a perforated mobile base, which vibrated at a defined amplitude and frequency. Potato cubes consisting of 5 and 10 mm edges were dried and the behavior of the particles during drying was phenomenologically studied. Shrinkage of potato cubes during drying adequately fit the uniform drying model up to a moisture content of 0.9 kg water/kg dry potato. During the drying of cubes with 5 and 10 mm edges, cracks appear on the faces of the cubes. Fornell's modified model, denoted a good fit to the experimental points, and allowed the generation of characteristic drying curves both at the vary the temperature as the speed of the drying air, useful for computational modeling.

SYSTEMIC REVIEW ON VOICE ACTUATED SMART HOPITAL BED

During the 20th century, medical beds underwent technological advancements, especially making them smarter in patient care. The past fifteen years have brought various changes in the concept of smart bed technology, but no definitive evidence of the project's existence has been presented. These and previous systems typically use at least one push button or pressure-sensitive type switch to implement various control and articulation capabilities. Smart beds are designed to assist patients with mobility issue as it will allow them to control bed movement by themself and help them return to normal movement more quickly, with the presence of a monitoring system that alerts nursing staff when patients move and leave the bed with side rails. This type of high-end bed contributes greatly to the recovery of the patient's physical condition, health and activity because it is the main factor in achieving this goal, according to studies that have confirmed that the patient's movement during hospital stay as contributed to his quick recovery and early discharge from the hospital.

River dynamics - a geospatial analysis of Jamuna (Brahmaputra) River in Bangladesh during 1973-2019 using Landsat satellite remote sensing data and GIS.

The present study is designed to illuminate the dynamics of the Jamuna River in Bangladesh for 46years, from 1973 to 2019. About 240km of the Jamuna River course was assessed using remote sensing and GIS. Landsat remote sensing imageries were processed, and bank lines were extracted and analysed using GIS. The main objective of the study was to understand the pattern of bed movement of the Jamuna River. The river dynamics were assessed based on bank erosion, accretion, bank line shifts, channel width, and river course and confluence shift. Area vulnerable to erosion was assessed using historical erosion rate and trend analysis. The result revealed that the river area increased by about 48% over 46years. The total eroded area was about 1038 km2, with 35.40% more erosion on the left bank than on the right. Due to higher erosion than deposition, the river widened. The average width of the river increased by about 56.40% during the period. The average rate of shifting was higher on the left bank than on the right, indicating the eastward movement of the river. Impact analysis showed that overall, a total of 822 km2 and 390 km2 of croplands and settlements were eroded during the period 1973-2019. The width of the confluence at the Padma River junction decreased by about 28%. The straight shift of the confluence was 9.27km towards the southeast. The vulnerable area assessment anticipated that there would be more erosion on the left bank than on the right, and that Kurigram, Tangail and Jamalpur are the districts most susceptible to future left bank erosion. And, the lower reach of the right bank of the Padma River is at high vulnerable to erosion at the confluence. The methods and analysis adopted in this study can be applied to any other braided river to monitor the dynamics of the river and to formulate an action plan to protect the river from erosion.

Feasibility of using abbreviated scan protocols with population-based input functions for accurate kinetic modeling of [18F]-FDG datasets from a long axial FOV PET scanner

BackgroundAccurate kinetic modeling of 18F-fluorodeoxyglucose ([18F]-FDG) positron emission tomography (PET) data requires accurate knowledge of the available tracer concentration in the plasma during the scan time, known as the arterial input function (AIF). The gold standard method to derive the AIF requires collection of serial arterial blood samples, but the introduction of long axial field of view (LAFOV) PET systems enables the use of non-invasive image-derived input functions (IDIFs) from large blood pools such as the aorta without any need for bed movement. However, such protocols require a prolonged dynamic PET acquisition, which is impractical in a busy clinical setting. Population-based input functions (PBIFs) have previously shown potential in accurate Patlak analysis of [18F]-FDG datasets and can enable the use of shortened dynamic imaging protocols. Here, we exploit the high sensitivity and temporal resolution of a LAFOV PET system and explore the use of PBIF with abbreviated protocols in [18F]-FDG total body kinetic modeling.MethodsDynamic PET data were acquired in 24 oncological subjects for 65 min following the administration of [18F]-FDG. IDIFs were extracted from the descending thoracic aorta, and a PBIF was generated from 16 datasets. Five different scaled PBIFs (sPBIFs) were generated by scaling the PBIF with the AUC of IDIF curve tails using various portions of image data (35–65, 40–65, 45–65, 50–65, and 55–65 min post-injection). The sPBIFs were compared with the IDIFs using the AUCs and Patlak Ki estimates in tumor lesions and cerebral gray matter. Patlak plot start time (t*) was also varied to evaluate the performance of shorter acquisitions on the accuracy of Patlak Ki estimates. Patlak Ki estimates with IDIF and t* = 35 min were used as reference, and mean bias and precision (standard deviation of bias) were calculated to assess the relative performance of different sPBIFs. A comparison of parametric images generated using IDIF and sPBIFs was also performed.ResultsThere was no statistically significant difference between AUCs of the IDIF and sPBIFs (Wilcoxon test: P > 0.05). Excellent agreement was shown between Patlak Ki estimates obtained using sPBIF and IDIF. Using the sPBIF55–65 with the Patlak model, 20 min of PET data (i.e., 45 to 65 min post-injection) achieved < 15% precision error in Ki estimates in tumor lesions compared to the estimates with the IDIF. Parametric images reconstructed using the IDIF and sPBIFs with and without an abbreviated protocol were visually comparable. Using Patlak Ki generated with an IDIF and 30 min of PET data as reference, Patlak Ki images generated using sPBIF55–65 with 20 min of PET data (t* = 45 min) provided excellent image quality with structural similarity index measure > 0.99 and peak signal-to-noise ratio > 55 dB.ConclusionWe demonstrate the feasibility of performing accurate [18F]-FDG Patlak analysis using sPBIFs with only 20 min of PET data from a LAFOV PET scanner.

Flood disturbance mediates the strength of stream trophic cascades caused by trout

AbstractTrophic cascades are important features of aquatic ecosystems, but much variation in their strength remains unexplained. Disturbance could restrict cascade occurrence by limiting predator distribution, and increase cascade strength by lowering defended herbivore abundance. These possibilities were investigated in 20 New Zealand rivers varying both in flooding disturbance (measured by bed movement) and presence of non‐native predatory trout. Trout were often, but not always, associated with indirectly increasing algal abundance compared to similar rivers with native galaxiid fishes. Floods explained variation in cascades by (1) resetting algal abundance such that algal minima were related to bed movement; (2) preventing occurrence by restricting trout abundance in the most disturbed rivers; and (3) increasing potential cascade strength by removing defended herbivores. These observations indicate strong nonlinear influences of disturbance on both trophic cascade occurrence and maximum strength which will be important to consider as climate change alters disturbance regimes.

Impact of a PMMA tube on performances of a Vereos PET/CT system adapted for BSL-3 environment according to the NEMA NU2-2012 standard

IntroductionA Vereos PET/CT device was adapted to be compatible with the experimentation in large animals within BSL-3 environment. The aim of this study was to investigate the impact of this modification on the performance according to NEMA NU2-2012 standard.MethodsSpatial resolution, sensitivity, count rate performance, accuracies of corrections and image quality were assessed using the NEMA NU2-2012 standards before and after installation of a transparent poly-methyl methacrylate tube of 8 mm thickness, 680 mm diameter and 2800 mm long inside the tunnel of the system. In addition, CT performance tests were performed according to manufacturer standard procedure.ResultsAlthough the presence of the tube led to a slight decrease in sensitivity, performance measurements were in accordance with manufacturer preconisation ranges and comparable to previous performance published data.ConclusionModifications of Vereos PET/CT system allowing its use in BSL-3 conditions did not affect significantly its performance according to NEMA NU2-2012 standard.Key pointsQuestion. Does a BSL-3 compatible modification alter Philips Vereos PET/CT performances according to NEMA NU2-2012 standards?Pertinent findings. Our Vereos PET/CT system was modified by a wall separating BSL-1 and BSL-3 sides and an 8 mm thickness PMMA tube inserted into the bore of the camera in order to extend the BSL-3 containment along the bed movement. The performances of our modified system according to NEMA NU2-2012 standards were not significantly impacted by the modifications and were in accordance with the values prescribed by the manufacturer.Implications for patients care. Our clinical PET/CT device was modified for human infectious diseases studies in Non-Human Primates. This unusual set up may then provide truly transposable data from preclinical studies into clinical application in infected patients.

Rural hospital bed management practices during influenza season.

Rural health services face greater challenges in managing infectious patients due to lack of specialty beds and longer lengths of stay. The pressures of seasonal influxes of influenza patients with a heavy burden of chronic disease and an ageing population result in an increased demand for hospital beds. During these peak periods it is common for rural hospitals to experience bed block. The result is that patients may be placed into any available bed or ward at the time, increasing the need for transfer and the risk of spreading hospital-acquired respiratory illnesses to other patients and staff across the hospital. This further exacerbates bed block, with patients then requiring more specialised treatment and longer lengths of stay. This places additional strain on already existing workforce shortages and limited resources that must accommodate higher-than-normal patient loads. The objective of this study was to examine rural hospital bed management practices with a focus on the transfer of patients who are actively diagnosed with influenza (either on admission or during their stay in hospital) and to investigate the association of increased bed movement with the rate of nosocomial transmission and staff workload. The rates of patients admitted to a rural hospital in New South Wales, Australia, during the yearly peak influenza season (July to September) during 2016-2019 with either community-acquired or hospital-acquired influenza were examined using an infection control surveillance program. Bed management practices related to these inpatients were audited to examine their contribution towards nosocomial transmissions and staff workload during these periods. A total of 229 patients presented to this hospital with an influenza diagnosis over the study period and generated 175 bed transfers. Forty percent of community-acquired and 70% of hospital-acquired influenza inpatients experienced one or more intrahospital bed transfers during their active infection period. Half of all bed transfers involved patients being transferred to another ward (interward) and the other half consisted of those transferred within the same ward (intraward). These transfers impacted staff workload, requiring a total of 245 extra hours from nursing and cleaning staff to facilitate - time not included when allocating staff at the start of each shift. Findings from this study indicate that there is no active strategy for influenza containment during high-occupancy periods for this rural facility. This resulted in multiple bed transfers occurring during the active phase of influenza infection. This then led to an exacerbation of bed block and thus further inappropriate placement of newly admitted patients. The development of an optimal bed management plan for future surges of influenza and other highly infectious respiratory illnesses is essential to reduce nosocomial infection and staff workload, especially given the limited resources available in rural areas compared to metropolitan centres.

Habitat size influences community stability

Mechanisms linked to demographic, biogeographic, and food-web processes thought to underpin community stability could be affected by habitat size, but the effects of habitat size on community stability remain relatively unknown. We investigated whether those habitat-size-dependent properties influenced community instability and vulnerability to perturbations caused by disturbance. This is particularly important given that human exploitation is contracting ecosystems, and abiotic perturbations are becoming more severe and frequent. We used a perturbation experiment in which 10 streams, spanning three orders of magnitude in habitat size, were subjected to simulated bed movement akin to a major flood disturbance event. We measured the resistance, resilience, and variability of basal resources, and population and community-level responses across the stream habitat-size gradient immediately before, and at 0.5, 5, 10, 20, and 40 d post-disturbance. Resistance to disturbance consistently increased with stream size in all response variables. In contrast, resilience was significantly higher in smaller streams for some response variables. However, this higher resilience of small ecosystems was insufficient to compensate for their lower resistance, and communities of smaller streams were thus more variable over time than those of larger streams. Compensatory dynamics of populations, especially for predators, stabilized some aspects of communities, but these mechanisms were unrelated to habitat size. Together, our results provide compelling evidence for the links between habitat size and community stability, and should motivate ecologists and managers to consider how changes in the size of habitats will alter the vulnerability of ecosystems to perturbations caused by environmental disturbance.

Transient versus sustained biophysical responses to dam removal

Dams fragment the longitudinal flux of sediment and obstruct fish passage. To help remediate these impacts, dam removal has become an important tool in the river restoration toolkit. Scientifically, these removals also provide an important experimental design, fixed in time and space, to quantify geomorphic and ecological responses to removal of a disturbance. Using the removal of a 6 m high dam in Massachusetts (USA), we quantify the immediate and subsequent channel and ecological recovery to test whether the immediate ecological/geomorphic responses were sustained or transient. Initial geomorphic adjustments have been generally sustained since removal, especially for bed sediment size, where initial fining and reduction in bed caliber size has been maintained over the course of the study. Sampling of transported passive integrated transponder (PIT) tagged clasts indicates that the median of bedload grain sizes now corresponds to surface median grain sizes below the former dam. Channel cross-sectional area varied irregularly downstream initially but is now spatially uniform. Pool filling, however, has been a transient response as initial aggradation shifted to sediment evacuation. Ecologically, upstream establishment of resident fish species previously restricted to below-dam locations occurred in the first year after removal. Upstream expansion increased upstream species richness and has been maintained throughout the study period, in spite of the variability in presence and abundance of rare and migratory species such as the anadromous Sea lamprey (Petromyzon marinus). In contrast, a reduction in abundance of resident species in dam proximal sites in 2012 appears to be a transient response to abrupt and intense bed movement associated with removal of the dam, as numbers recovered and, in some cases, exceeded pre-dam removal levels. Overall, we found that immediate (within the first 1–2 yr), sustained effects on geomorphology and ecology dominated the response to dam removal in this system, a finding that may be generally applicable to small dam removals in upland catchments.

Regimes of primary production and their drivers in Alpine streams

Abstract Primary production is a fundamental ecosystem process that influences nutrient and carbon cycling, and trophic structure in streams. The magnitude and timing of gross primary production (GPP) are typically controlled by hydrology, light, nutrient availability and grazers. Estimates of GPP and its drivers in high‐mountain streams remain elusive at present. We estimated GPP in streams typical for high‐mountain catchments, namely a glacier‐fed, groundwater‐fed (krenal) and a snowmelt‐fed (nival) stream. Using high‐resolution sensor data over 2 years in combination with numerical simulations of stream hydraulics, we studied the periods of GPP characteristic for these streams, as well as their major drivers. Favourable windows for GPP were constrained to periods at the onset of the snowmelt and its recession, when photosynthetic active radiation at the streambed and streambed stability facilitated GPP. During these windows of opportunity, GPP was higher in the nival stream (3.7 ± 3.4 g O2 m−2 day−1), followed by the glacier‐fed (1.5 ± 1.6 g O2 m−2 day−1) and the krenal streams (0.6 ± 0.6 g O2 m−2 day−1). GPP was largely controlled by photosynthetic active radiation at the stream bottom, however, we were not able to establish an unequivocal relationship between flow‐induced bed movement and GPP. Our results highlight the capacity of primary producers to exploit the discrete and relatively predictable windows of opportunities in high‐mountain streams. We propose that climate‐driven change in snow and glacier melt reduction may ameliorate stream environmental conditions, thereby enhancing the potential autochthonous organic matter supply within the catchment.

Experimental Study of Cuttings Transport with Non-Newtonian Fluid in an Inclined Well Using Visualization and Electrical Resistance Tomography Techniques

Summary Hole cleaning is a concern in directional and horizontal well drilling operations where drill cuttings tend to settle in the lower annulus section. Laboratory-scale experiments were performed with different non-Newtonian fluids in a 6.16-m-long, 114.3- × 63.5-mm transparent annulus test section to investigate cuttings transport behavior. This experimental study focused on understanding the cuttings transport mechanism in the annulus section with high-speed imaging technology. The movement of cuttings in the inclined annular section was captured with a high-speed camera at 2,000 frames/sec. Also, cuttings bed movement patterns at different fluid velocities and inner pipe rotations were captured with a digital single-lens reflex video camera. The electrical resistance tomography (ERT) system was used to quantify the cuttings volume fraction in the annulus. Different solid bed heights and cuttings movements were observed based on fluid rheology, fluid velocity, and inner pipe rotation. The mechanistic three-layer cuttings transport model was visualized with the experimental procedure. This study showed that solid bed height is significantly reduced with an increase in the inner pipe rotation. This study also identified that cuttings bed thickness largely depends on fluid rheology and wellbore inclination. The image from the high-speed camera identified a downward trend of some rolling particles in the annulus caused by gravitational force at a low mud velocity. Visual observation from a high-speed camera identified a helical motion of solid particles when the drillpipe is in contact with solid particles and rotating at a higher rev/min. Different cuttings movement patterns such as: rolling, sliding, suspension, helical movement, and downward movement were identified from the visualization of a high-speed camera.

Biological Cohesion as the Architect of Bed Movement Under Wave Action

AbstractCohesive extracellular polymeric substances (EPS) generated by microorganisms abundant on Earth are regarded as bed “stabilizers” increasing the erosion threshold in sedimentary systems. However, most observations of this phenomenon have been taken under steady flow conditions. In contrast, we present how EPS affect the bed movement under wave action, showing a destabilization of the system. We demonstrate a complex behavior of the biosedimentary deposits, which encompasses liquefaction, mass motion, varying bed formations and erosion, depending on the amount of EPS present. Small quantities of EPS induce higher mobility of the sediments, liquefying an otherwise stable bed. Bed with larger quantities of EPS undergoes a synchronized mechanical oscillation. Our analysis clarifies how biological cohesion can potentially put coastal wetlands at risk by increasing their vulnerability to waves. These findings lead to a revised understanding of the different roles played by microbial life, and their importance as mediators of seabed mobility.

Development and Initial Results of a Brain PET Insert for Simultaneous 7-Tesla PET/MRI Using an FPGA-Only Signal Digitization Method.

In study, we developed a positron emission tomography (PET) insert for simultaneous brain imaging within 7-Tesla (7T) magnetic resonance (MR) imaging scanners. The PET insert has 18 sectors, and each sector is assembled with two-layer depth-of-interaction (DOI)-capable high-resolution block detectors. The PET scanner features a 16.7-cm-long axial field-of-view (FOV) to provide entire human brain images without bed movement. The PET scanner early digitizes a large number of block detector signals at a front-end data acquisition (DAQ) board using a novel field-programmable gate array (FPGA)-only signal digitization method. All the digitized PET data from the front-end DAQ boards are transferred using gigabit transceivers via non-magnetic high-definition multimedia interface (HDMI) cables. A back-end DAQ system provides a common clock and synchronization signal for FPGAs over the HDMI cables. An active cooling system using copper heat pipes is applied for thermal regulation. All the 2.17-mm-pitch crystals with two-layer DOI information were clearly identified in the block detectors, exhibiting a system-level energy resolution of 12.6%. The PET scanner yielded clear hot-rod and Hoffman brain phantom images and demonstrated 3D PET imaging capability without bed movement. We also performed a pilot simultaneous PET/MR imaging study of a brain phantom. The PET scanner achieved a spatial resolution of 2.5 mm at the center FOV (NU 4) and a sensitivity of 18.9 kcps/MBq (NU 2) and 6.19% (NU 4) in accordance with the National Electrical Manufacturers Association (NEMA) standards.

Holographic patient tracking after bed movement for augmented reality neuronavigation using a head-mounted display

BackgroundHolographic neuronavigation has several potential advantages compared to conventional neuronavigation systems. We present the first report of a holographic neuronavigation system with patient-to-image registration and patient tracking with a reference array using an augmented reality head-mounted display (AR-HMD).MethodsThree patients undergoing an intracranial neurosurgical procedure were included in this pilot study. The relevant anatomy was first segmented in 3D and then uploaded as holographic scene in our custom neuronavigation software. Registration was performed using point-based matching using anatomical landmarks. We measured the fiducial registration error (FRE) as the outcome measure for registration accuracy. A custom-made reference array with QR codes was integrated in the neurosurgical setup and used for patient tracking after bed movement.ResultsSix registrations were performed with a mean FRE of 8.5 mm. Patient tracking was achieved with no visual difference between the registration before and after movement.ConclusionsThis first report shows a proof of principle of intraoperative patient tracking using a standalone holographic neuronavigation system. The navigation accuracy should be further optimized to be clinically applicable. However, it is likely that this technology will be incorporated in future neurosurgical workflows because the system improves spatial anatomical understanding for the surgeon.

Predicting adult neuroscience intensive care unit admission from emergency department triage using a retrospective, tabular-free text machine learning approach

Early admission to the neurosciences intensive care unit (NSICU) is associated with improved patient outcomes. Natural language processing offers new possibilities for mining free text in electronic health record data. We sought to develop a machine learning model using both tabular and free text data to identify patients requiring NSICU admission shortly after arrival to the emergency department (ED). We conducted a single-center, retrospective cohort study of adult patients at the Mount Sinai Hospital, an academic medical center in New York City. All patients presenting to our institutional ED between January 2014 and December 2018 were included. Structured (tabular) demographic, clinical, bed movement record data, and free text data from triage notes were extracted from our institutional data warehouse. A machine learning model was trained to predict likelihood of NSICU admission at 30 min from arrival to the ED. We identified 412,858 patients presenting to the ED over the study period, of whom 1900 (0.5%) were admitted to the NSICU. The daily median number of ED presentations was 231 (IQR 200–256) and the median time from ED presentation to the decision for NSICU admission was 169 min (IQR 80–324). A model trained only with text data had an area under the receiver-operating curve (AUC) of 0.90 (95% confidence interval (CI) 0.87–0.91). A structured data-only model had an AUC of 0.92 (95% CI 0.91–0.94). A combined model trained on structured and text data had an AUC of 0.93 (95% CI 0.92–0.95). At a false positive rate of 1:100 (99% specificity), the combined model was 58% sensitive for identifying NSICU admission. A machine learning model using structured and free text data can predict NSICU admission soon after ED arrival. This may potentially improve ED and NSICU resource allocation. Further studies should validate our findings.

Daily entropy of dissolved oxygen reveals different energetic regimes and drivers among high‐mountain stream types

AbstractHigh‐resolution time series of dissolved oxygen (DO) have revealed different ecosystem energetics regimes across various stream types. Ecosystem energetic regimes are relevant to better understand the transformation and retention of nutrients and carbon in stream ecosystems. However, the patterns and controls of stream energetics in high‐mountain landscapes remain largely unknown. Here we monitored percent DO saturation (every 10 min) over 2 years in a glacier‐fed, krenal (groundwater‐fed) and a nival (snowmelt‐fed) stream as they are typical for the high mountains. We used daily Shannon entropy to explore the temporal dynamics of stream water DO and to infer information on the ecosystem energetics and on the potential drivers. We found that discharge modulated the drivers of DO variations at daily and seasonal scales. Elevated bed movement along with high turbidity and very high gas exchange rates drove the daily DO patterns in the glacier‐fed stream during snow and ice melt, whereas light seemed to drive DO dynamics in the krenal and nival streams. We found a window of favorable conditions for potential gross primary production (GPP) during the onset of the snowmelt in the glacier‐fed stream, whereas potential GPP seemed to extend over longer periods in the krenal and nival streams. Our findings suggest how the energetic regimes of these high‐mountain streams may change in the future as their biological and physical drivers change owing to climate warming.

Continuous In-Bed Monitoring of Vital Signs Using a Multi Radar Setup for Freely Moving Patients

In hospitals, continuous monitoring of vital parameters can provide valuable information about the course of a patient’s illness and allows early warning of emergencies. To enable such monitoring without restricting the patient’s freedom of movement and comfort, a radar system is attached under the mattress which consists of four individual radar modules to cover the entire width of the bed. Using radar, heartbeat and respiration can be measured without contact and through clothing. By processing the raw radar data, the presence of a patient can be determined and movements are categorized into the classes “bed exit”, “bed entry”, and “on bed movement”. Using this information, the vital parameters can be assessed in sections where the patient lies calmly in bed. In the first step, the presence and movement classification is demonstrated using recorded training and test data. Next, the radar was modified to perform vital sign measurements synchronized to a gold standard device. The evaluation of the individual radar modules shows that, regardless of the lying position of the test person, at least one of the radar modules delivers accurate results for continuous monitoring.

Improving the bed movement physics of inclined grate biomass CFD simulations

Extensive research has been performed in the field of biomass combustion, particularly in terms of numerical simulations. However, only a few studies have deepened the understanding of the dynamics of packed beds and boiler grates.This paper presents and assesses a new physical solution under a comprehensive Eulerian model that tackles the complex problem of biomass movements inside a packed boiler bed. In addition, this paper improves the precision of the obtained results, expanding the application cases of the simulation model produced by the GTE research group at the University of Vigo (Spain). The modelling algorithms are based on mechanisms that represent the crumbling of biomass particles due to gravity and the movements caused by the push generated by the feeding system. The movements’ logic affects the variables involved in the biomass thermal conversion formulation, which is integrated with other combustion models previously presented by the authors.To test the performance of the presented models, a 3D experimental grate was printed and fed with biomass pellets. The performance was compared to that of the evolution of the simulated bed. Several experiments were performed to analyse parameters, such as the bed size, slope and residence time of different fuel batches. The results of the comparison show agreement in the behaviour of the model in terms of the bed size, shape and slope for different instances of the feeding process. Otherwise, the experiments show that the internal distribution of the bed layers of different batches presents some differences with the predictions. Therefore, possible improvements, such as considering a friction factor, may be applied to the model to upgrade its performance.