Simultaneous Access Research Articles

Characterization of aerosol and assessment of the risk of transmission of SARS-COV-2 VIRUS in a natural thermal cave

Thermal caves represent an environment characterized by unique chemical-physical properties, often used by customers for treatment and care of musculoskeletal, respiratory and skin diseases. The recent pandemic caused by COVID-19 has imposed the need to investigate the potential transmission scenario of SARS-CoV-2 virus also in such atypical and poorly studied indoor environments. This research work was carried out inside a natural thermal cave located in Italy where a waterfall of sulfur-sulfate-bicarbonate-alkaline earth mineral thermal water creates a warm-humid environment with 100% humidity and 48°C temperature. A characterization of the aerosol was carried out in terms of number, surface area and mass, as well as particle size distributions. The physical characteristics of the aerosol were measured inside the natural thermal cave and in other immediately adjacent areas in two different days and in two distinct moments by means of an optical spectrometer. The data obtained showed a predominance of particles with a diameter greater than 8 μm, associated with a low ability of penetration in the human respiratory system. Subsequently, through a model recently proposed in scientific literature, it was evaluated the airborne transmission risk of SARS-CoV-2 inside the cave by quantifying the probability of infection due to exposure in a microenvironment in presence of a SARS-CoV-2 infected subject. The infection risk was evaluated for different scenarios obtained combining parameters such as physical, breathing or talking activities of the occupants, simultaneous or non-simultaneous access to the cave and mechanical ventilation activated or non-activated. In terms of the risk of SARS-CoV-2 infection, evaluated under the hypotheses of the model, it was highlighted the decisive effect of the mechanical ventilation system on the risk of contagion: for all the hypothesized scenarios, there is a substantial reduction in the risk of contagion considering the ventilation system active. Furthermore, the adoption of social distancing measures such as non-simultaneous access to the cave makes the risk of contagion extremely low, according to the assumptions underlying the model, even with the mechanical ventilation system not active.

Commentary: Prone Transpsoas Technique for Simultaneous Single-Position Access to the Anterior and Posterior Lumbar Spine.

Commentary: Prone Transpsoas Technique for Simultaneous Single-Position Access to the Anterior and Posterior Lumbar Spine.

Prone Transpsoas Technique for Simultaneous Single-Position Access to the Anterior and Posterior Lumbar Spine.

Effective decompression, arthrodesis, and correction of spinal conditions frequently utilize operative approaches that expose both the anterior and posterior spinal column. Until now, circumferential spinal column access often requires the surgeon to reposition and drape the patient multiple times or utilize a posterior only approach that has limited anterior correction capability or to utilize a lateral-only approach that complicates otherwise traditional posterior surgical maneuvers. To describe a technique utilizing a single surgical position that enables minimally disruptive anterior column correction with simultaneous access to the posterior spinal column. The operative technique for accessing the lateral lumbar interbody space from a prone transpsoas (PTP) approach is described. The rationale for this approach and a representative case example are reviewed. The PTP approach was used to perform an L3-4 and L4-5 interbody fusion in a 71-yr-old female with spondylolisthesis, severe stenosis, and locked facets. The PTP approach enabled efficient completion of an anterior column correction, direct posterior decompression, multi-segment pedicle fixation, and maintenance of alignment, all while in a single prone position. There were no intraoperative or postoperative complications. The authors' early experience with the described PTP technique suggests it is not only feasible but offers some advantages, as it allows for single-position surgery maximizing both anterior and posterior column access and corrective techniques. Further follow-up studies of this technique are ongoing.

Взаимодействие энергетического оборудования с сетевыми устройствами, поддерживающими интернет-протоколы прикладного уровня

The implementation of interaction between high-voltage power equipment with computer network devices in monitoring systems involves the use of proprietary Internet protocols that do not meet the criteria of free software and are not always compatible with the Internet protocols of personal computers. To solve this problem, it is proposed to use an intermediate link between the industrial and computer networks. This link is a network bridge built using the PPP protocol, which unites automatic devices equipped with UART interfaces with a computer network of the 802.11n (Wi-Fi) standard. The article presents several models for organizing bridges: a centralized network bridge on the side of a router and client computer, a distributed bridging system, and a dedicated bridge. Based on the accomplished analysis, it is recommended to use a centralized model for a network that has to comply with more stringent reliability requirements. If there is a need to have simultaneous access to several automation devices and high data exchange rates, a distributed model should be used. A dedicated bridge is used only in special cases, for example, when a high compactness is required in implementing a monitoring system.

Resource Allocation and Joint Mode Selection for Device-to-Device Communications Using Cuckoo Search Algorithm

In this study, Resource Allocation and Joint Mode Selection for Device-to-Device Communications (D2D) has been modelled using the cuckoo search algorithm (CSA). The implementation is made for equal power control and constraints ensuring that the existing sub-channels are used efficiently and optimally. Simultaneous access to radio resources in a coexistence scenario through D2D technology with optimal mode selection is considered. Initially, the problem formulation for resource allocation is written, then, a cuckoo search optimized solution for optimal resource allocation and mode selection in uplink cellular communications has been proposed and the same has been evaluated using throughput analysis.

Near-surface rheology and hydrodynamic boundary condition of semi-dilute polymer solutions.

Understanding confined flows of complex fluids requires simultaneous access to the mechanical behaviour of the liquid and the boundary condition at the interfaces. Here, we use evanescent wave microscopy to investigate near-surface flows of semi-dilute, unentangled polyacrylamide solutions. By using both neutral and anionic polymers, we show that monomer charge plays a key role in confined polymer dynamics. For solutions in contact with glass, the neutral polymers display chain-sized adsorbed layers, while a shear-rate-dependent apparent slip length is observed for anionic polymer solutions. The slip lengths measured at all concentrations collapse onto a master curve when scaled using a simple two-layer depletion model with non-Newtonian viscosity. A transition from an apparent slip boundary condition to a chain-sized adsorption layer is moreover highlighted by screening the charge with additional salt in the anionic polymer solutions. We anticipate that our study will be a starting point for more complex studies relating the polymer dynamics at interfaces to their chemical and physical composition.

A Beacon-less Multi-channel Packet Forwarding Scheme in Vehicular Networks

The ad-hoc vehicular network is a sub stream of an ad-hoc mobile network where the nodes can converse and know each other by their periodic control packet dissemination. In vehicular network communication, the available bandwidth is limited. The parallel and multi-vehicle channel access will create an unwanted delay during the packet dissemination. The node may compete with each other to access the channel during parallel communication. The simultaneous channel access will increase network overload. The proposed approach will minimize the channel access collision through the variable time slots. Before any data dissemination, the node will send a Channel Booking Request (CBR) message to a correspondent node. The spectrum allocation is based on the type of vehicle and message_code. The concept has experimented with traditional routing protocols for overtaking assistance. The proposed approach is compared with the packet delivery rate, jitter, and packet loss rate.

Impactos da política nacional de atenção básica nas taxas de mortalidade infantil sob a ótica da estratégia de saúde da família

Este estudo buscou analisar os impactos da Política Nacional de Atenção Básica (PNAB) nas taxas de mortalidade infantil no âmbito da Estratégia de Saúde da Família (ESF). Para isso foi realizado uma revisão integrativa na Biblioteca Virtual em Saúde por meio do acesso simultâneo às bases de dados BDENF, CVSP e LILACS, utilizando os seguintes descritores: “Estratégia Saúde da Família” e “Mortalidade Infantil”. 49 publicações foram encontradas inicialmente, porém apenas oito artigos foram incluídos na análise final. Verificou-se uma redução drástica da taxa de mortalidade infantil a partir do momento de expansão da ESF pelas regiões mais carentes do Brasil, favorecendo uma queda deste indicador com consequente melhoria na qualidade da assistência à saúde e na qualidade de vida, pondo o Brasil com uma das nações de maior evolução neste âmbito, proporcionada principalmente pelas ações que a PNAB desenvolveu ao longo dos anos. Desta forma, as publicações analisadas por esta revisão demonstraram que a PNAB contribui para que as taxas de mortalidade infantil alcancem valores ainda menores, principalmente pelas ações desempenhadas pelas equipes de saúde em especial os enfermeiros.

A Unified Database Solution to Process BIM and GIS Data

For many years, the objective of spatial databases created using Geographic Information System (GIS) technology was to provide information about large spaces and areas outside of buildings. Building Information Modeling (BIM) technology focused mainly on small spaces, indoor and outdoor, targeted at other users and slightly different applications, was developed simultaneously for several dozen years. The significant development of GIS technology and new tools for quick data acquisition (e.g., laser scanning) and growing user needs resulted in the geoinformation modeling of the space inside buildings as well. BIM, on the other hand, began to be used for increasingly larger spaces outside buildings. Technology developers, users, and scientists started to notice that works turned out to be repetitive and that combining two different technologies is necessary; however, it is not simple. The research presented in the article is another attempt at connecting the world of BIM and GIS. The proposed integrated database environment of BIM/GIS spatial data makes it possible to store GIS and BIM data, enabling the use of the same data by both types of systems simultaneously and in a consistent manner. This allows BIM systems to to obtain simultaneous access to BIM and GIS data, which may be needed in, for example, the process of analyzing a building and its immediate surroundings. At the same time, GIS can obtain up-to-date building data necessary for spatial analyses, building management, or route mapping in navigation applications. The concept proposed in this article assumes a pragmatic approach, which is based on sharing Industry Foundation Classes (IFC) and CityGML schemas from a single database for BIM and GIS applications in their practically original form using an additional integrated BIM-GIS schema, called BIGI-S. The research joins some other works in this field, complementing them and adding a new perspective. This paper describes the concept of this solution, including specific data structures, data conversion algorithms, and a prototype solution. The tests carried out by the authors prove the robustness of the adopted concept and its technical feasibility.

In-Operando Study of Shape Retention and Microstructure Development in a Hydrolyzing Sol-Gel Ink during 3D-Printing.

3D printing of amorphous and crystalline ceramics is of paramount importance for the fabrication of a wide range of devices with applications across different technology fields. Printed ceramics are remarkably enabled by the sol-gel synthesis method in conjunction with continuous filament direct ink writing. During printing, multiple processes contribute to the evolution of inks including shape retention, chemical conversion, solidification, and microstructure formation. Traditionally, depending on the ink composition and printing environment, several mechanisms have been associated with the shape retention and solidification of 3D printed structures: gelation, rapid solvent evaporation, energy-driven phase transformation, and chemical-driven phase transformation. Understanding the fundamental differences between these mechanisms becomes key since they strongly influence the spatiotemporal evolution of the materials, as the out-of-equilibrium processes inherent to the extrusion, relaxation, and solidification of printed materials have significant effects on the materials properties. In this work, we investigate the shape retention mechanism and the hydrolysis-induced material conversion and microstructure formation during the 3D printing of a water reactive sol-gel ink that transforms into titanium dioxide-based ceramic. This study aims at identifying characteristic mechanisms associated with the material transformation, establishing connections between the microstructure development and the timescales associated with solidification under operando 3D-printing conditions. The investigation of this material's out-of-equilibrium pathways under processing conditions is enabled by time-resolved coherent X-ray scattering, providing simultaneous access to temporospatially resolved microstructural and dynamics information. Furthermore, we explore X-ray speckle tracking as a tool to resolve deformations of the microstructure in a printed filament associated with the deposition of consecutive filaments. Through this work, we aim at providing a fundamental understanding of the relationships behind these transformative processes in 3D printing and their timescales as the basis for achieving unprecedented control over printed materials microstructure.

Integration of Diamond-Based Quantum Emitters with Nanophotonic Circuits.

Nanophotonics provides a promising approach to advance quantum technology by replicating fundamental building blocks of nanoscale quantum optic systems in large numbers with high reproducibility on monolithic chips. While photonic integrated circuit components and single-photon detectors offer attractive performance on silicon chips, the large-scale integration of individually accessible quantum emitters has remained a challenge. Here, we demonstrate simultaneous optical access to several integrated solid-state spin systems with Purcell-enhanced coupling of single photons with high modal purity from lithographically positioned nitrogen vacancy centers into photonic integrated circuits. Photonic crystal cavities embedded in networks of tantalum pentoxide-on-insulator waveguides provide efficient interfaces to quantum emitters that allow us to optically detect magnetic resonances (ODMR) as desired in quantum sensing. Nanophotonic networks that provide configurable optical interfaces to nanoscale quantum emitters via many independent channels will allow for novel functionality in photonic quantum information processors and quantum sensing schemes.

Meshed Bluetree: Time-Predictable Multimemory Interconnect for Multicore Architectures

Multicore architectures are widely adopted in the emerging real-time applications, such as autonomous vehicles and robotics, where latency is required to be both bounded in the worst case (i.e., time predictability) and low. With the number of processors growing, the conventional memory interconnects, i.e., shared bus, crossbar, and network-on-chip (NoC), suffer high latency due to the increasing logic size of their centralized arbiter, which is deployed for time predictability. In this article, we introduce a novel distributed multimemory interconnect, Meshed Bluetree, and explain its operation. Constructed by coupling a router network with multiple Bluetree-based memory architectures in parallel, Meshed Bluetree allows simultaneous access to multiple memory modules. We present the analysis for the predictable timing behavior of memory access to bound the worst case. The evaluation of FPGA with synthetic memory workloads and real-world benchmarks demonstrates the effectiveness of our work, i.e., as the number of memory modules increases, the latency is reduced with the same scale. This work reports the first time-predictable distributed multimemory interconnect, significantly contributing to multicore real-time systems.

Blood Flow Imaging with Ultrafast Doppler.

The pulsed-Doppler effect is the main technique used in clinical echography to assess blood flow. Applied with conventional focused ultrasound Doppler modes, it has several limits. Firstly, a finely tuned signal filtering operation is needed to distinguish blood flows from surrounding moving tissues. Secondly, the operator must choose between localizing the blood flows or quantifying them. In the last two decades, ultrasound imaging has undergone a paradigm shift with the emergence of ultrafast ultrasound using unfocused waves. In addition to a hundredfold increase in framerate (up to 10000 Hz), this new technique also breaks the conventional quantification/localization trade-off, offering a complete blood flow mapping of the field of view and a simultaneous access to fine velocities measurements at the single-pixel level (down to 50 µm). This data continuity in both spatial and temporal dimensions strongly improves the tissue/blood filtering process, which results in an increase sensitivity to small blood flow velocities (down to 1 mm/s). In this method paper, we aim to introduce the concept of ultrafast Doppler as well as its main parameters. Firstly, we summarize the physical principles of unfocused wave imaging. Then, we present the Doppler signal processing main steps. Particularly, we explain the practical implementation of the critical tissue/blood flow separation algorithms and on the extraction of velocities from these filtered data. This theoretical description is supplemented by in vitro experiences. A tissue phantom embedding a canal with flowing blood-mimicking fluid is imaged with a research programmable ultrasound system. A blood flow image is obtained and the flow characteristics are displayed for several pixels in the canal. Finally, a review of in vivo applications is proposed, showing examples in several organs such as carotids, kidney, thyroid, brain and heart.

Random-Access Accelerator (RAA): A Framework to Speed Up the Random-Access Procedure in 5G New Radio for IoT mMTC by Enabling Device-To-Device Communications.

Mobile networks have a great challenge by serving the expected billions of Internet of Things (IoT) devices in the upcoming years. Due to the limited simultaneous access in the mobile networks, the devices should compete between each other for resource allocation during a Random-Access procedure. This contention provokes a non-depreciable delay during the device’s registration because of the great number of collisions experienced. To overcome such a problem, a framework called Random-Access Accelerator (RAA) is proposed in this work, in order to speed up network access in massive Machine Type Communication (mMTC). RAA exploits Device-To-Device (D2D) communications, where devices with already assigned resources act like relays for the rest of devices trying to gain access in the network. The simulation results show an acceleration in the registration procedure of 99%, and a freed space of the allocated spectrum until 74% in comparison with the conventional Random-Access procedure. Besides, it preserves the same device’s energy consumption compared with legacy networks by using a custom version of Bluetooth as a wireless technology for D2D communications. The proposed framework can be taken into account for the standardization of mMTC in Fifth-Generation-New Radio (5G NR).

Stationary Waiting Time in Parallel Queues with Synchronization

Motivated by database locking problems in today’s massive computing systems, we analyze a queueing network with many servers in parallel (files) to which jobs (writing access requests) arrive according to a Poisson process. Each job requests simultaneous access to a random number of files in the database and will lock them for a random period of time. Alternatively, one can think of a queueing system where jobs are split into several fragments that are then randomly routed to specific servers in the network to be served in a synchronized fashion. We assume that the system operates on a first-come, first-served basis. The synchronization and service discipline create blocking and idleness among the servers, which leads to a strict stability condition compared with other distributed queueing models. We analyze the stationary waiting time distribution of jobs under a many-server limit and provide exact tail asymptotics. These asymptotics generalize the celebrated Cramér–Lundberg approximation for the single-server queue.

Cannabinoid CB1 Receptors in the Intestinal Epithelium Are Required for Acute Western-Diet Preferences in Mice

The endocannabinoid system plays an important role in the intake of palatable food. For example, endocannabinoid signaling in the upper small-intestinal epithelium is increased (i) in rats after tasting dietary fats, which promotes intake of fats, and (ii) in a mouse model of diet-induced obesity, which promotes overeating via impaired nutrient-induced gut–brain satiation signaling. We now utilized a combination of genetic, pharmacological, and behavioral approaches to identify roles for cannabinoid CB1Rs in upper small-intestinal epithelium in preferences for a western-style diet (WD, high-fat/sucrose) versus a standard rodent diet (SD, low-fat/no sucrose). Mice were maintained on SD in automated feeding chambers. During testing, mice were given simultaneous access to SD and WD, and intakes were recorded. Mice displayed large preferences for the WD, which were inhibited by systemic pretreatment with the cannabinoid CB1R antagonist/inverse agonist, AM251, for up to 3 h. We next used our novel intestinal epithelium-specific conditional cannabinoid CB1R-deficient mice (IntCB1−/−) to investigate if intestinal CB1Rs are necessary for WD preferences. Similar to AM251 treatment, preferences for WD were largely absent in IntCB1−/− mice when compared to control mice for up to 6 h. Together, these data suggest that CB1Rs in the murine intestinal epithelium are required for acute WD preferences.

Single spectrum three-material decomposition with grating-based x-ray phase-contrast CT

Grating-based x-ray phase-contrast imaging provides three simultaneous image channels originating from a single image acquisition. While the phase signal provides direct access to the electron density in tomography, there is additional information on sub-resolutional structural information which is called dark-field signal in analogy to optical microscopy. The additional availability of the conventional attenuation image qualifies the method for implementation into existing diagnostic routines. The simultaneous access to the attenuation coefficient and the electron density allows for quantitative two-material discrimination as demonstrated lately for measurements at a quasi-monochromatic compact synchrotron source. Here, we investigate the transfer of the method to conventional polychromatic x-ray sources and the additional inclusion of the dark-field signal for three-material decomposition. We evaluate the future potential of grating-based x-ray phase-contrast CT for quantitative three-material discrimination for the specific case of early stroke diagnosis at conventional polychromatic x-ray sources. Compared to conventional CT, the method has the potential to discriminate coagulated blood directly from contrast agent extravasation within a single CT acquisition. Additionally, the dark-field information allows for the clear identification of hydroxyapatite clusters due to their micro-structure despite a similar attenuation as the applied contrast agent. This information on materials with sub-resolutional microstructures is considered to comprise advantages relevant for various pathologies.

A Decoupled Learning Strategy for Massive Access Optimization in Cellular IoT Networks

Cellular-based networks are expected to offer connectivity for massive Internet of Things (mIoT) systems. However, their Random Access CHannel (RACH) procedure suffers from unreliability, due to the collision from the simultaneous massive access. Despite that this collision problem has been treated in existing RACH schemes, these schemes usually organize IoT devices' transmission and re-transmission along with fixed parameters, thus can hardly adapt to time-varying traffic patterns. Without adaptation, the RACH procedure easily suffers from high access delay, high energy consumption, or even access unavailability. With the goal of improving the RACH procedure, this paper targets to optimize the RACH procedure in real-time by maximizing a long-term hybrid multi-objective function, which consists of the number of access success devices, the average energy consumption, and the average access delay. To do so, we first optimize the long-term objective in the number of access success devices by using Deep Reinforcement Learning (DRL) algorithms for different RACH schemes, including Access Class Barring (ACB), Back-Off (BO), and Distributed Queuing (DQ). The converging capability and efficiency of different DRL algorithms including Policy Gradient (PG), Actor-Critic (AC), Deep Q-Network (DQN), and Deep Deterministic Policy Gradient (DDPG) are compared. Inspired by the results from this comparison, a decoupled learning strategy is developed to jointly and dynamically adapt the access control factors of those three access schemes. This decoupled strategy integrates predicted traffic into the learning process to improve training efficiency, where a Recurrent Neural Network (RNN) model is first employed to predict the real-time traffic values of the network environment, and then multiple DRL agents are employed to cooperatively configure parameters of each RACH scheme. Our results demonstrate that the decoupled strategy remarkably accelerate the training speedy.

Non-genetic factors that influence methamphetamine intake in a genetic model of differential methamphetamine consumption.

Genetic and non-genetic factors influence substance use disorders. Our previous work in genetic mouse models focused on genetic factors that influence methamphetamine (MA) intake. The current research examined several non-genetic factors for their potential influence on this trait. We examined the impact on MA intake of several non-genetic factors, including MA access schedule, prior forced MA exposure, concomitant ethanol (EtOH) access, and gamma-aminobutyric acid type B (GABAB) receptor activation. Selectively bred MA high drinking(MAHDR) and low drinking (MALDR) mice participated in this research. MAHDR, but not MALDR, mice increased MA intake when given intermittent access, compared with continuous access, with a water choice under both schedules. MA intake was not altered by previous exposure to forced MA consumption. Male MAHDR mice given simultaneous access to MA, EtOH, and an EtOH+MA mixture exhibited a strong preference for MA over EtOH and EtOH+MA; MA intake was not affected by EtOH in female MAHDR mice. When independent MAHDR groups were given access to MA, EtOH, or EtOH+MA vs. water in each case, MA intake was reduced in the water vs. EtOH+MA group, compared with the water vs. MA group. The GABAB receptor agonist R(+)-baclofen (BAC) not only reduced MA intake but also reduced water intake and locomotor activity in MAHDR mice. There was a residual effect of BAC, such that MA intake was increased after termination of BAC treatment. These findings demonstrate that voluntary MA intakein MAHDR mice is influenced by non-genetic factors related to MA access schedule and co-morbid EtOH exposure.

Channel model for simultaneous backhaul and access for mmWave 5G outdoor street canyon channel

Millimeter waves (mmWaves) with very wide frequency bands are proposed for 5G new radio to deliver higher data-speed and capacity. Transmission using mmWaves suffers significant path loss and can be compensated by employing directional antennas. The narrow-beam directional antennas act as spatial filters that filter out multipaths falling outside their beam area. This, together with the insignificance of diffraction and diffused scattering in urban outdoors causes mmWave outdoor channel multipath to be spatially sparse with few specular reflections, posing unique requirements on channel modeling. In this paper, we have derived a low complexity mmWave directional channel model based on ray tracing for the urban microcell street canyon environment. A comprehensive characterization of outdoor links in various realistic scenarios including, line of sight (LOS)/non-LOS, beam aligned/unaligned and road canyon with/without crossroads is presented. The model captures azimuth and elevation directions of propagation in 3D plane by using a highly directional horn antenna design. Atmospheric absorption loss of mmWave is also modeled to enhance the model’s accuracy and generality. The model is validated against measurements reported in the literature. Furthermore, the channel is studied for varying propagation conditions, antenna beamwidths and polarizations, transmitter/receiver heights and positions, and street deployment parameters. Additionally, we propose a metaheuristic algorithm called particle swarm optimization to simultaneously optimize the deployment parameters that minimize path loss as the objective function. The proposed model helps in mmWave system evaluation without the necessity for any costly measurement setup or complex off-the-shelf ray tracing model.