Ichthyoplankton Species Composition and Assemblages From the Estuary to the Hukou Section of the Changjiang River

Estuary river–lake (ERL) complex is critical for the development of ichthyoplankton, which plays an essential role in the breeding, nursing, and recruitment of freshwater fish species. In this study, different ERL sections were selected to investigate the ichthyoplankton assemblage from the Changjiang River estuary to its Hukou section between May 2018 and August 2020. During the study period, fish larvae of 40, 35, 54, and 46 fish species were sampled in the Rugao (RG), Nanjing (NJ) (nearby estuary), Anqing (AQ), and Hukou (HK) (connected river–lake) sections in the Changjiang River, respectively. Results on ichthyoplankton surveys revealed fluctuating assemblage patterns in the different river sections; larval fish species composition presented ecological habitat-dependent characteristics, which supported the importance of ERL complex for ichthyoplankton development. Furthermore, the density of fish larvae was negatively correlated with water transparency but positively correlated with water temperature, the daily rate of water level increase, and runoff in the limitative range. A generalized additive model analysis indicated that the hydrological factors significantly affecting larval fish abundance are water temperature, transparency, the daily rate of water level increase, and runoff (p < 0.05). These results also indicated that river estuaries and river–lake connected complexes are essential for ichthyoplankton recruitment and migration. In combination with the historical record, ichthyoplankton assemblage’s patterns in the Changjiang River lower reaches were preliminarily elucidated, although additional works are needed such as assessing effects on their survival and recruitment.

Best Practices for Managing Subsea Well Plug and Abandonment Operation in Offshore Malaysia During COVID-19 Pandemic

In 2020, PCSB implemented the first permanent Plug & Abandonment (P&A) campaign for three Subsea wells in a gas field offshore Malaysia. The main objective of the campaign was to establish two (2) barriers for every movable hydrocarbon or overpressure bearing sand by placing laterally extended cement plug across impermeable formation with enough formation strength to handle the pressure of the formation to be isolated. The unique case of this operation was the challenges to execute PCSB's first subsea P&A operation in gas field Malaysia during pandemic situation. In March 2020, the Malaysian government imposed Movement Control Order (MCO) to curb the spread of the COVID-19. A semi-submersible rig was on-hired a week after government initiated the MCO, resulted in the rig preparation being badly hampered due to manpower management and material fabrication and delivery. PCSB was exposed to expensive rig daily rate that had to be managed. Four (4) main challenges were encountered during operation: safe protection for workers, expensive standby cost, manpower management and material fabrication and delivery. This paper, from the ‘project management’ point of view, describes the journey of managing rig operation during PCSB's first subsea wells P&A in Malaysia efficiently amidst the pandemic by reducing the impact of COVID-19 on project cost. With the experience of managing rig for subsea well operation, a complex operation in Malaysia, amidst pandemic, PCSB sharing on the experience is beneficial to provide context setting and benchmark on maintaining the efficiency of operation. Wells successfully met the objective of operation with no incident occurred, negotiated reduction on standby cost and managed to bring critical manpower on time during operation.

Assessment of the fatality rate and transmissibility taking account of undetected cases during an unprecedented COVID-19 surge in Taiwan

Background During the COVID-19 outbreak in Taiwan between May 11 and June 20, 2021, the observed fatality rate (FR) was 5.3%, higher than the global average at 2.1%. The high number of reported deaths suggests that hospital capacity was insufficient. However, many unexplained deaths were subsequently identified as cases, indicating that there were a few undetected cases, hence resulting in a higher estimate of FR. Knowing the number of total infected cases can allow an accurate estimation of the fatality rate (FR) and effective reproduction number (Rt). Methods After adjusting for reporting delays, we estimated the number of undetected cases using reported deaths that were and were not previously detected. The daily FR and Rt were calculated using the number of total cases (i.e. including undetected cases). A logistic regression model was developed to predict the detection ratio among deaths using selected predictors from daily testing and tracing data. Results The estimated true daily case number at the peak of the outbreak on May 22 was 897, which was 24.3% higher than the reported number, but the difference became less than 4% on June 9 and afterward. After taking account of undetected cases, our estimated mean FR (4.7%) was still high but the daily rate showed a large decrease from 6.5% on May 19 to 2.8% on June 6. Rt reached a maximum value of 6.4 on May 11, compared to 6.0 estimated using the reported case number. The decreasing proportion of undetected cases was associated with the increases in the ratio of the number of tests conducted to reported cases, and the proportion of cases that are contact-traced before symptom onset. Conclusions Increasing testing capacity and tracing efficiency can lead to a reduction of hidden cases and hence improvement in epidemiological parameter estimation.

Holiday Rentals in Cultural Tourism Destinations: A Comparison of Booking.com-Based Daily Rate Estimation for Seville and Porto

Multiple variables determine holiday rentals’ price composition in cultural tourism destinations. This study sought, first, to test a model including the variables with the greatest impact on tourism accommodations’ prices in these destinations and, second, to demonstrate the proposed model’s applicability to cultural city destinations by identifying the adaptations needed to apply it to different contexts. Two cities were selected for the model application—Seville in Spain and Porto in Portugal—both of which are located in different countries and are well-known cultural tourism destinations. The data were extracted from Booking.com because this accommodations platform has adapted its offer to the sharing economy, becoming one of the most important players in the market, and because research on holiday rentals using data from Booking.com is scarce. The results show that the variables used are relevant and highlight the adaptations necessary for specific cultural tourism destinations, thereby indicating that the model can be applied to all cultural tourism destinations. The proposed approach can help holiday rental managers select the correct tools for determining their accommodation units’ daily rates according to their product and marketing context’s characteristics.

Inclusion of Condominium Units in Luxury Hotels as a Diversification Strategy: Property Performance Perspective

There is a new wave of mixed development where luxury hotels come with condominium units, though this type of diversification has gained scant attention. Prior hospitality literature on diversification strategies has mostly taken the firm-level approach and documented its impact on performance from various angles such as brand diversification, segment diversification, and geographic diversification, therefore leaving a void. In this work, we use the multilevel mixed effect model to examine 15,340 property-level data points from 2010 to 2019 for U.S. luxury hotels with and without condominium units. Our objective is to compare, at a property level, the performances of luxury hotels with condominium units with the performances of those not having condominium units and to determine whether the difference varies by hotel location. Our findings suggest that the Average Daily Rate (ADR), Revenue per Available Room (RevPAR), and Total Revenue per Available Rooms (TRevPAR) of luxury hotels with condominium units were significantly higher than those of hotels without condominium units. Significant moderating effect of location was found for Occupancy, ADR, Food and Beverage Revenue per Available Rooms (F&B RevPAR), and TRevPAR while no such effect was found for RevPAR and GOPPAR.

Non-financial factors affecting the operational performance of hospitality companies: Evidence from Vietnam

Non-financial factors including quality of services, the flexibility of a company, utilization of resources, and market orientation are regarded as significant determinants that enhance the profitability-based performance of a service company or a hotel. The study investigated the interaction between these factors and hotel operating performance measured by the hospitality performance and results indicators. Data on 346 executives of Vietnam’s hospitality companies were collected. A structural equation modeling (SEM) method was utilized to examine the positive-direct and moderating effects of non-financial factors on hotel performance in terms of occupancy rate (OCR), average daily rate (ADR), and the revenue per available room (RevPAR). The findings showed that service quality ( = 0.118, p < 0.05), flexibility ( = 0.173, p < 0.05) and resource utilization (= 0.172, p < 0.05) positively affected the performance of Vietnam’s hospitality companies. Meanwhile, innovation showed no direct influence (p = 0.068) but an indirect impact on the performance through service quality ( = 0.311, p < 0.05). Market orientation did not impact the performance (p = 0.076) but it positively affected both innovation ( = 0.322, p < 0.05) and service quality ( = 0.146, p < 0.05). The study contributed to a theoretical enhancement of the current level of knowledge on the factors that affect the performance and developed a reliable scale for measuring the performance of hotels in Vietnam.

Coastal Erosion And Tourism: The Case Of The Distribution Of Tourist Accommodations And Their Daily Rates

Beaches are key territories for tourist development but at risk of impacts of climate change—specifically with the consequent intensification of coastal erosion. This study examines the effects of coastal erosion on the distribution of lodging facilities and the value of daily rates practiced on the beaches of Tabuba and Cumbuco on the northeast coast of Brazil. The methodology comprises collecting information on the means of accommodation (distribution and daily rate), quantifying coastline variation and measuring the field to validate data. A total of 13.9 km of coastline were analyzed; erosion tendency was observed in 26.8% of the coast (9.0% erosion, 14.4% intense erosion, and 3.4% severe erosion). With the highest erosion rates, Tabuba's Beach has a low density in accommodation distribution and daily rates practiced in tourism. Cumbuco's Beach, conversely, has a lower risk of erosion, and the means of accommodation are concentrated. Coastal erosion has affected tourism development in Caucaia, influencing the choice of tourism accommodation entrepreneurs. the results indicate that there is a clear concentration of tourist accommodations in areas without notorious problems with coastal erosion, influencing in the distribution of tourist facilities and their daily rates. So, there is a direct connection does exist between local tourism system income and the beaches with problems with coastal erosion.

High Post-infection Protection after COVID-19 Among Healthcare Workers: A Population-Level Observational Study Regarding SARS-CoV-2 Reinfection, Reactivation, and Re-positivity and its Severity

Introduction: Even though over a year has passed since the coronavirus 2019 (COVID-19) outbreak, our information regarding certain aspects of the disease, such as post-infection immunity is still very limited. This study aimed to evaluate post-infection protection and COVID-19 features among healthcare workers (HCWs), during three subsequent surges.Method: The study population consisted of all HCWs in either public or private hospitals in Fars province, Southern Iran from 20 April 2020 up to 20th February 2021. We calculated the rate of infection as the number of individuals with positive PCR tests divided by the cumulative number of person-days at risk. Poisson regression was utilized to calculate the adjusted rate ratio and estimated protection. Results: During the study period, a total of 30,546 PCR tests were performed among HCWs, of which 13,749 HCWs were positive. Among a total of 141 diagnosed cases who experienced a second episode of COVID-19, 44 (31.2%) cases of reactivation and relapse, and 97 (68.8% of infected and 1.81% of total HCWs) cases of reinfection was observed. The daily rate of infection was 4.72 for previously infected HCWs, while 2.20 for HCWs without previous infection. The estimated protection against repeat infection after a previous SARS-CoV-2 infection was 94.8% (95% CI: 93.6-95.7).Conclusion: Re-positivity, relapse, and reinfection of SARS-CoV-2 are quite rare in the population of HCWs. Also, after a first episode of infection, estimated protection of 94.8% was achieved against repeat infections.

Analyzing the Influence of Salinity on Produced Water Re-Injection

Produced water reinjection (PWRI) is one of the methods employed by oilfield operators to optimize production while conforming to increasingly stringent produced water disposal policies. Different produced water species from different facilities also have different salinities as a result of entrainment of treatment fluids, precipitation of salts at surface conditions, etc. During re-injection operations, the salinity of the injection fluid has to be accounted for as it affects the production. Previous studies have focused on laboratory analysis by core flooding. While this approach is indeed reasonable and offers a first-hand impression of the reservoir conditions, it presents a problem of cost and the age-old opinion that the core sample may not be representative of the entire reservoir. Therefore, I have employed a computer modeling approach using a commercial simulator to analyze the influence of salinity on production during produced water re-injection. It was found that the salinity truly affects production. Re-injection of produced water with salinity equal to the reservoir salinity of 1000 ppm was compared to three cases of re-injection of produced water from extraneous sources having salinities of 100 ppm, 500 ppm and 10000 ppm. It was found that salinity of 10000 ppm gave the best oil production performance for the reservoir model; a daily rate of 40 STB/DAY and an oil cumulative production of 40,000 STB. Incremental salinity of injected produced water led to incremental oil recovery. The mechanism resulting in incremental recovery was attributed to the increase in viscosity and decrease in mobility as the salinity increases.

Airbnb’s Success: Does It Depend on Who Is Measuring?

Because individual listing data for Airbnb typically are not publicly available, private companies have emerged to estimate the performance of Airbnb listings. The implicit assumption of a growing number of academics, policymakers, and consultants is that Airdna’s performance measures are directly comparable with those of STR. We argue that Airdna’s measures of Occupancy, Average Daily Rate (ADR), and Revenue per Available Room (RevPAR) do not conform to industry standards and exhibit significant bias. We expand available evidence by explicitly quantifying the sources and magnitude of the biases for Airdna’s performance measures for Airbnb listings. Using Airdna’s individual listing data for Virginia between the first quarter of 2015 and the 4th quarter of 2019, we find, on average, Airdna’s performance measures for Occupancy, ADR, and RevPAR were biased upward by 60 percent, 78 percent, and 179 percent, respectively.