Indoor Event Research Articles

Superspreading of SARS-CoV-2 at a choir rehearsal in Finland-A computational fluid dynamics view on aerosol transmission and patient interviews.

COVID-19 pandemic has highlighted the role of aerosol transmission and the importance of superspreading events. We analyzed a choir rehearsal in November 2020, where all participants, except one who had recently earlier recovered from COVID-19, were infected. We explore the risk factors for severe disease in this event and model the aerosol dispersion in the rehearsal room. Characteristics of participants were collected by interviews and supplemented with patient records. A computational simulation of aerosol distribution in the rehearsal room and the efficacy of potential safety measures was conducted using the Large-Eddy Simulation approach. Infection risk was studied by analyzing quanta emission and exposure with the Wells-Riley equation. The simulation showed that airborne transmission likely explains this mass contagion event. Every singer was exposed to the virus in only 5 min from the beginning of the rehearsal, and maximum concentration levels were reached at 20 min the concentration levels started to approach a steady state after 20 min. Although concentration differences existed in the room, risk levels near (1 m) and far (5 m) from the aerosol source were similar for certain singers. Modeling indicated infection risk levels of 70-100% after one hour; the risk would have been considerably reduced by wearing high-filtration respirators. Age and pre-existing comorbidities predicted more severe disease. The high incidence of illness may be partly attributed to the relatively high median age of individuals. Additionally, those admitted to the hospital had multiple underlying health conditions that predispose them to more severe disease. Airborne transmission and indoor space can explain this mass exposure event. High-filtration respirators could have prevented some infections. The importance of safety distances diminishes the longer the indoor event. The concept of safety distance is challenging, as our study suggests that long range airborne transmission may occur in indoor events with extended duration. We encourage informing the public, especially persons at risk, of safety measures during epidemics.

A Randomized Controlled Trial to Study the Transmission of SARS-CoV-2 and Other Respiratory Viruses During Indoor Clubbing Events (ANRS0066s ITOC Study).

In the context of the circulation of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.617.2 (Delta) variant, vaccination re-authorized mass indoor gatherings. The "Indoor Transmission of coronavirus disease 2019 (COVID-19)" (ITOC) trial (ClinicalTrials.gov, NCT05311865) aimed to assess the risk of transmission of SARS-CoV-2 and other respiratory viruses during an indoor clubbing event among participants fully vaccinated against COVID-19. ITOC, a randomized controlled trial in the Paris region (France), enrolled healthy volunteers aged 18-49 years, fully vaccinated against COVID-19, with no comorbidities or symptoms, randomized 1:1 to be interventional group "attendees" or control "non-attendees." The intervention was a 7-hour indoor event in a nightclub at full capacity, with no masking, prior SARS-CoV-2 test result, or social distancing required. The primary outcome measure was the number of reverse transcriptase-polymerase chain reaction (RT-PCR)-determined SARS-CoV-2-positive subjects using self-collected saliva 7 days post-gathering in the per-protocol population. Secondary endpoints focused on 20 other respiratory viruses. Healthy participants (n = 1216) randomized 2:1 by blocks up to 10 815 attendees and 401 non-attendees, yielding 529 and 287 subjects, respectively, with day-7 saliva samples. One day-7 sample from each group was positive. Looking at all respiratory viruses together, the clubbing event was associated with an increased risk of infection of 1.59 (95% CI, 1.04-2.61). In the context of low Delta variant of concern circulation, no evidence of SARS-CoV-2 transmission among asymptomatic and vaccinated participants was found, but the risk of other respiratory virus transmission was higher. Clinical Trials Registration. ClinicalTrials.gov, NCT05311865.

A coupled experimental and statistical approach for an assessment of SARS-CoV-2 infection risk at indoor event locations

Indoor event locations are particularly affected by the SARS-CoV-2 pandemic. At large venues, only incomplete risk assessments exist, whereby no suitable measures can be derived. In this study, a physical and data-driven statistical model for a comprehensive infection risk assessment has been developed. At venues displacement ventilation concepts are often implemented. Here simplified theoretical assumptions fail for the prediction of relevant airflows for airborne transmission processes. Thus, with locally resolving trace gas measurements infection risks are computed more detailed. Coupled with epidemiological data such as incidences, vaccination rates, test sensitivities, and audience characteristics such as masks and age distribution, predictions of new infections (mean), situational R-values (mean), and individual risks on- and off-seat can be achieved for the first time. Using the Stuttgart State Opera as an example, the functioning of the model and its plausibility are tested and a sensitivity analysis is performed with regard to masks and tests. Besides a reference scenario on 2022-11-29, a maximum safety scenario with an obligation of FFP2 masks and rapid antigen tests as well as a minimum safety scenario without masks and tests are investigated. For these scenarios the new infections (mean) are 10.6, 0.25 and 13.0, respectively. The situational R-values (mean) – number of new infections caused by a single infectious person in a certain situation – are 2.75, 0.32 and 3.39, respectively. Besides these results a clustered consideration divided by age, masks and whether infections occur on-seat or off-seat are presented. In conclusion this provides an instrument that can enable policymakers and operators to take appropriate measures to control pandemics despite ongoing mass gathering events.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Transmission Associated With an Indoor Music Event That Required Proof of Full Vaccination Against Coronavirus Disease 2019 (COVID-19) Prior to Entry-Seattle, July 2021.

In July 2021, Public Health – Seattle and King County–investigated a COVID-19 outbreak at an indoor event intended for fully-vaccinated individuals, revealing unvaccinated staff, limited masking, poor ventilation, and overcrowding. Supporting businesses to develop and implement comprehensive COVID-19 prevention plans is essential for reducing spread in these settings. Word Count: 48/50

Transmission of and Infection With COVID-19 Among Vaccinated and Unvaccinated Attendees of an Indoor Wedding Reception in Minnesota

Characterizing rates of SARS-CoV-2 infection among vaccinated and unvaccinated persons with the same exposure is critical to understanding the association of vaccination with the risk of infection with the Delta variant. Additionally, evidence of Delta variant transmission by children to vaccinated adults has important public health implications. To characterize transmission and infection of SARS-CoV-2 among vaccinated and unvaccinated attendees of an indoor wedding reception. This cohort study included attendees at an indoor wedding reception in Minnesota in July 2021. Data were collected from REDCap surveys and routine surveillance interviews. The full list of attendees and a partial list of emails were obtained. Fifty-seven attendees completed the emailed survey. Eighteen additional attendees were identified from the state health department COVID-19 surveillance database. Attendance at an indoor event. Risk of SARS-CoV-2 infection among vaccinated and unvaccinated attendees, identification of an index case, whole genome sequencing (WGS) to identify the COVID-19 variant, understanding of transmission patterns, and assessment of secondary transmission. The primary case definition was an individual with a positive SARS-CoV-2 test who attended the wedding in the 14 days prior to their illness. Data were gathered for 75 attendees (mean [SE] age, 37.5 [13.7] years; 57 [76%] female individuals), of whom 56 (75%) were fully vaccinated, 4 (5%) were partially vaccinated, and 15 (20%) were unvaccinated. Of 62 attendees who were tested, 29 (47%) tested positive, including 16 of 46 fully vaccinated attendees (35%), 2 of 4 partially vaccinated attendees (50%), and 11 of 12 unvaccinated attendees (92%). Being unvaccinated was associated with a higher risk of infection compared with being vaccinated (risk ratio, 2.64; 95% CI, 1.71-4.06; P = .001). One unvaccinated adult required hospitalization. An unvaccinated child who was symptomatic on the event date was identified as the index case. Eleven specimens were available for WGS. All sequenced specimens were closely related and were identified as the Delta variant. WGS supported secondary transmission from a vaccinated individual with SARS-CoV-2. This cohort study identified a COVID-19 Delta variant outbreak at an indoor event despite a high proportion of vaccinated attendees. It found that vaccination was associated with a reduced risk of infection.

Same-day SARS-CoV-2 antigen test screening in an indoor mass-gathering live music event: a randomised controlled trial

BackgroundThe banning of mass-gathering indoor events to prevent SARS-CoV-2 spread has had an important effect on local economies. Despite growing evidence on the suitability of antigen-detecting rapid diagnostic tests (Ag-RDT) for mass screening at the event entry, this strategy has not been assessed under controlled conditions. We aimed to assess the effectiveness of a prevention strategy during a live indoor concert.MethodsWe designed a randomised controlled open-label trial to assess the effectiveness of a comprehensive preventive intervention for a mass-gathering indoor event (a live concert) based on systematic same-day screening of attendees with Ag-RDTs, use of facial masks, and adequate air ventilation. The event took place in the Sala Apolo, Barcelona, Spain. Adults aged 18–59 years with a negative result in an Ag-RDT from a nasopharyngeal swab collected immediately before entering the event were randomised 1:1 (block randomisation stratified by age and gender) to either attend the indoor event for 5 hours or go home. Nasopharyngeal specimens used for Ag-RDT screening were analysed by real-time reverse-transcriptase PCR (RT-PCR) and cell culture (Vero E6 cells). 8 days after the event, a nasopharyngeal swab was collected and analysed by Ag-RDT, RT-PCR, and a transcription-mediated amplification test (TMA). The primary outcome was the difference in incidence of RT-PCR-confirmed SARS-CoV-2 infection at 8 days between the control and the intervention groups, assessed in all participants who were randomly assigned, attended the event, and had a valid result for the SARS-CoV-2 test done at follow-up. The trial is registered at ClinicalTrials.gov, NCT04668625.FindingsParticipant enrollment took place during the morning of the day of the concert, Dec 12, 2020. Of the 1140 people who responded to the call and were deemed eligible, 1047 were randomly assigned to either enter the music event (experimental group) or continue with normal life (control group). Of the 523 randomly assigned to the experimental group, 465 were included in the analysis of the primary outcome (51 did not enter the event and eight did not take part in the follow-up assessment), and of the 524 randomly assigned to the control group, 495 were included in the final analysis (29 did not take part in the follow-up). At baseline, 15 (3%) of 495 individuals in the control group and 13 (3%) of 465 in the experimental group tested positive on TMA despite a negative Ag-RDT result. The RT-PCR test was positive in one case in each group and cell viral culture was negative in all cases. 8 days after the event, two (<1%) individuals in the control arm had a positive Ag-RDT and PCR result, whereas no Ag-RDT nor RT-PCR positive results were found in the intervention arm. The Bayesian estimate for the incidence between the experimental and control groups was –0·15% (95% CI –0·72 to 0·44).InterpretationOur study provides preliminary evidence on the safety of indoor mass-gathering events during a COVID-19 outbreak under a comprehensive preventive intervention. The data could help restart cultural activities halted during COVID-19, which might have important sociocultural and economic implications.FundingPrimavera Sound Group and the #YoMeCorono Initiative.TranslationFor the Spanish translation of the abstract see Supplementary Materials section.

Relationship Between Reaction Time, Medal Winning and Performance in the 60 m Hurdle Indoor Event Before and After the Change of False Start Rule

Summary 60 m hurdles races are included in the World Indoor Athletics Championships and consist the shortest hurdle race distance. Thus, it is possible that the reaction time (RT) affects the finish time (t60mH) and the rank of the hurdlers. The aims of this research were: a) to examine the relationship between RT and t60mH, b) the possible differentiation of RT: c) between the hurdlers who won a medal in World Indoor Athletics Championships (WM) and those who did not (NMW), d) between hurdlers who competed before (BRC) and after (ARC) the change of the starting rules in 2009. Analysis included 70 performances (WM: n = 28; NMW: n = 42; BRC: n = 32; ARC, n = 38). The differences between WM and NMW and BRC and ARC were examined with independent samples T-test, while the possible relationship between RT and t60mH with Pearson’s correlation. The results showed that RT was not significantly different (p &lt; .05) between WM and NMW and between BRC and ARC. A weak, but significant, positive correlation (r = .228, p = .016) between RT and t60mH was observed. Results revealed that RT is a factor that affects t60mH. In conclusion, the essential focus on the reaction time at the starting blocks must be given during the training process.

Mathematical Modeling of Optimal Node Deployment for Indoor Wireless Sensor Networks

Wireless Sensor Network (WSN) has been utilized in environmental monitoring where large number of connected sensor nodes collaboratively sense and report conditions of the monitoring area. Indoor event sensing and tracking is one of WSN applications that has a significant effect on saving cost economically and humanitarianly. Efficient sensor node deployment can ensure coverage, connectivity, and stability of the network. This paper presents the mathematical modeling of a node deployment for indoor wireless sensor networks where the optimal number of nodes required to satisfy the coverage of the indoor area and network connectivity requirements is determined. The proposed solution contributes to the reduction in the cost and maintenance of the network as less number of sensors is needed, compared to the traditional grid node deployment.

Indoor Events Monitoring Using Channel State Information Time Series

By sensing wirelessly the radio propagation environment and analyzing the channel state information (CSI), one can extend human senses beyond our traditional reach and enrich the insight into the surrounding environment and activities, with or without line-of-sight. On one hand, different indoor activities bring distinctive perturbations to wireless radio propagations. On the other hand, thanks to the nature of multipaths, indoor environmental information is contained and embedded in the wireless CSI. Since the occurrence of an indoor event lasts for a certain period of duration and repeats a similar transition pattern among different realizations, information is embedded not only in each instantaneous CSI sample, but also in how CSI changes along time, e.g., the CSI time series. Inspired by that, this paper proposes an indoor monitoring system that monitors the occurrence of different indoor events in real time with commercial WiFi devices, by exploiting the temporal information embedded in the CSI time series. Through extensive experiments, this paper studies the robustness of the proposed system to variabilities in event instances and human motion interference, and its long-term performance in a one-month test.

Development of entertainment balloon robot system for an indoor event venue

This project revolves around the combination of different state-of-the-art concepts to create balloon robots which can be used for entertainment purposes. The goal is having multiple robots perform a choreographed flight on preset paths to make use of the “dead space” over the crowd of an event, either as part of the show or displaying information and advertisements. As the balloon is flying on a defined trajectory, a tracking system for its position is needed. For this purpose, several infrared cameras monitor the position of a marker attached to the balloon. The main challenge is overcoming the instabilities of the system to ensure a smooth and precise flight, resulting from the balloons structure: the balloon is filled with helium to counteract the forces of gravity and, therefore, minimize the work needed to keep its momentum. Finding a way to achieve this optimization and the precision mentioned beforehand is the task that we will present and solve in this paper.

TRIEDS: Wireless Events Detection Through the Wall

In this paper, we propose a novel wireless indoor events detection system, TRIEDS. By leveraging the time-reversal technique to capture the changes of channel state information (CSI) in the indoor environment, TRIEDS enables low-complexity single-antenna devices that operate in the ISM band to perform through-the-wall indoor multiple events detection. The multipath phenomenon denotes that the electromagnetic signals undergo different reflecting and scattering paths in a rich-scattering environment. In TRIEDS, each indoor event is detected by matching the instantaneous CSI to a multipath profile in a training database. To validate the feasibility of TRIEDS and to evaluate the performance, we build a prototype that works on ISM band with carrier frequency being 5.4 GHz and 125 MHz bandwidth. Experiments are conducted to detect the states of the indoor wooden doors. Experimental results show that with a single receiver access point and transmitter (client), TRIEDS can achieve a detection rate higher than 96.92% and a false alarm rate smaller than 3.08% under either line-of-sight (LOS) or non-LOS transmission.

High incidence of mild hyponatraemia in females using ecstasy at a rave party

Globally, millions of subjects regularly use ecstasy, a drug popular due to its empathogenic and entactogenic effects. Dilutional hyponatraemia, mainly caused by direct stimulation of antidiuretic hormone (ADH) secretion by ecstasy, is among the many side effects of the drug (active substance 3, 4-methylenedioxymethamphetamine, MDMA). Severe, symptomatic hyponatraemia related to the use of MDMA has been reported in more than 30 cases. The mortality of this complication is high and mainly females are involved. Dramatic cases that reach the literature probably represent the tip of the iceberg. We decided to study the incidence of hyponatraemia in subjects using MDMA at an indoor rave party. The study was performed at the indoor event 'Awakenings', held in Amsterdam in the fall of 2010. The plasma sodium concentration was measured at the party using a point of care method in 63 subjects using MDMA and 44 controls. The use of MDMA was confirmed by a urine test. The plasma sodium concentration in subjects using MDMA was significantly lower than in those not using the drug (138 ± 2 mmol/L versus 140 ± 2 mmol/L, respectively, P < 0.001). The overall incidence of hyponatraemia, defined as a plasma sodium concentration <136 mmol/L, was 14.3% in MDMA users (9/63 subjects). Most cases of hyponatraemia occurred in females, in whom the incidence was 26.7% (8 of 30 females), with lowest values of 133 mmol/L. The number of ecstasy pills ingested by the females developing hyponatraemia was not different from that ingested by those who did not develop this complication. Fluid intake in ecstasy users exceeded that of non-users, suggesting a dipsogenic effect of the drug. Only 3% of males, but no less than ∼25% of females attending a rave party and using MDMA developed mild hyponatraemia during the event. Especially females are therefore probably also at risk of developing severe symptomatic hyponatraemia. Not using MDMA is obviously the best option to prevent MDMA-induced hyponatraemia. However, accepting the fact that millions use the drug every weekend, strategies should also be developed to prevent hyponatraemia in subjects choosing to take MDMA. This would include matching the electrolyte content of the fluids and food ingested to that of the fluids that are lost during the use of MDMA, mainly by perspiration. Users of MDMA and emergency health care workers should become more aware of the relatively high incidence of MDMA-induced hyponatraemia and of potential strategies to prevent this complication.

Detection performance of security system using radio waves based on space-time signal processing

We proposed the indoor event detection system with signal subspace spanned by eigenvector for office or home security. The system monitors a whole room or home with only a pair of transmitter and receiver. The receiver uses an antenna array. We monitor events based on not received signal strength that is susceptible to noise but signal subspace spanned by eigenvector that is inherent to its environment. When an event (e.g. a person intrudes into a house) occurs, the propagation environment changes, and thus the signal subspace changes. Monitoring this change, we detect an event. The change of eigenvector tells us whether a person is in motion or remains motionless. We reported the principle of our security system and some fundamental detection performance of the system using dipole antennas arranged linearly or circularly as the receiver, although they are not necessarily arranged regularly. In this paper, we report various experimental detection results of the proposed security system using patch antennas set up on a box at the receiver such as intrusion, baggage stolen and the effect of outside of the room. Moreover, we evaluate the detection performance of the eigenvalue-based security system. We show that the eigenvalue-based security system can detect some events that the eigenvector-based security system cannot. Then we show that depending on application demands, using both the eigenvector and the eigenvalue for the security system is a promising technique.

Indoor Event Detection with Eigenvector Spanning Signal Subspace for Home or Office Security

This paper proposes an indoor event detection system for homes and offices that is based on electric wave reception such as intrusion into home or office. The proposed system places antenna array on the receiver side and detects events such as intrusion using the eigenvector spanning signal subspace obtained by the antenna array. The eigenvector is based on not received signal strengths (RSS) but direction of arrival (DOA) of incident signals on the antenna array. Therefore, in a static state, the variance of the eigenvector over time is smaller than that of RSS. The eigenvector changes only when the indoor environment of interest changes intermittently and statically, or dynamically. The installation cost is low, because the detection range is wide owing to indoor reflections and diffraction of electric wave and only a pair of transmitter and receiver are used. Experimental results reveal that the proposed method can distinguish the state when no event occurs and that when an event occurs clearly. Since the proposed method has a low false detection rate, it offers higher detection rates than the systems based on RSS.

Report on the Fifty-Eighth Annual Meeting

REPORT ON THE FIFTY-EIGHTH ANNUAL MEETING Sonoma, California June 14-17, 1995 Unable to persuade a more polarly located department to host the 1995 meetings, APCG awarded the Geography Departm ent at Sonoma State University (SSU) the honor. (In the general APCG scheme of things, this year’s meeting was to be hosted by a “north­ ern” institution.) Assisted by the university’s Center for Pan-Pacific Exchange and a generous grant from the Dean of the School of So­ cial Sciences, the on-campus event welcomed 172 participants, 148 of them paid (77 full registrants, 55 students, and 16 spouses). Members presented 62 papers on a wide range of subjects. The meetings opened on Wednesday evening with a powerful presenta­ tion on California’s Central Valley by noted author and Sonoma State English professor Gerry Haslam. The highlight of Friday’s full day of paper sessions was an interdisciplinary plenary round table on “Navigating Between Disciplines in the Pacific World/Rim,” orga­ nized by Tim Bell and SSU Anthropologist M argie Purser. On Saturday morning, President Betsy Bums put together a stimulating plenary session on “Innovations in Applied Urban Geography.” Betsy also presented her presidential address, “Life in the Fast Lane: Travel, Gender, and Community in Metropolitan Phoenix,” at the Friday Banquet. Two Wednesday afternoon workshops on GPS and ArcView, led by Sam Shaw and Bryan Baker, respectively, sold out. Field trips included Sharon Johnson’s foray into the Coast Range in Mendocino County, Mike Hearty’s look at Historical Landscapes in Sonoma County, a visit to Mare Island Naval Shipyard hosted by the local museum staff, Teresa Bulman’s and Debbie Elliott-Fisk’s Women and Wine in Sonoma County, and Doug Powell’sjaunt to Point Reyes. Our special field feature, the flying tours of the North Bay, led by 198 Annual Meeting Report 199 Art Hayssen of Santa Rosa Junior College, were reduced in number because of uncooperative weather (see Bar-B-Q below). No meeting in Sonoma County would be complete without a wine reception, which got things going on Wednesday evening. Thursday’s Bar-B-Q became an indoor event when unseasonal and unusual thun­ derstorms rolled through the area, dousing any outdoor prospects. Over 80 persons attended the banquet, and other events included the W omen’s Network breakfast and a department chairs’ lunch. Attendance at the meetings continued to produce some interest­ ing patterns. To no one’s surprise, Californians dominated— 111 of them. Arizona provided 24 representatives; Oregon 13; and Nevada 9. Somewhat more wondrous is the fact that as many folks came from Ohio as came from Washington! The distance records were set by Simon Zhao from Hong Kong Baptist University (who came to the meetings direct from Hong Kong) and Tatyana Sapozhnikov of the Russian Academy of Sciences (who was visiting at UC-Davis). Continuing a trend in recent years, several major research uni­ versities were notable by their absences. The U niversity of Washington maintained its perfect record of recent years with a goose egg all around (but if none of them could make it to Bellingham, it is not too surprising that they could not venture as far as Sonoma State). UCLA was represented only by an emeritus professor; UC-Berkeley only by one undergraduate, two grad students, and one emeritus pro­ fessor; UCSB by one faculty member. Summer meetings may be difficult for these colleagues. Let’s hope we see more of them when we return to fall meetings in 1997. Financially, the conference went very well and fattened APCG coffers by $4,051 (preliminary figure), which I suspect is a record profit for APCG meetings. We at Sonoma were happy to have all our APCG fellow mem­ bers here this year. Thanks to all of you who attended. Bill Crowley Sonoma State University ...