Field Survival of the Brown Marmorated Stink Bug Halyomorpha halys (Hemiptera: Pentatomidae) on California Tree Crops

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is a polyphagous insect pest that has invaded much of the United States, including California. Despite model predictions that regions in California like the agriculturally important Central Valley are suitable, H. halys populations and the occurring crop damage are distinctly lower than in regions of the East Coast. To evaluate if this is due to low nymphal survival in the high temperature and intensive monoculture environment, H. halys nymphs were caged on four common Central Valley tree crops: almond, pistachio, peach, and grape, and compared to the well-established almond and pistachio pest Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae). Nymphal development showed that peach, almond, and pistachio can sustain H. halys as single host plants until adult eclosion, whereas grapes cannot. The addition of fruiting structures of almond, pistachio, and grape to H. halys caged on peach trees (= mixed diet) did not increase nymphal survival but did increase adult female size. Leptoglossus zonatus survival was higher than H. halys on pistachio, but not on the other crops. Overall, H. halys nymphal mortality in the field was high, with 92% in the mixed diet compared to 73% in the mixed diet control in the laboratory, indicating abiotic population pressures. Our results confirm peach as a good H. halys host plant and suggest that almond has a similar suitability, and while pistachios can support H. halys nymphal development, they seem less likely to facilitate population growth.

The role of ambient parameters on transmission rates of the COVID-19 outbreak: A machine learning model

BACKGROUND

In recent years the relationship between ambient air temperature and the prevalence of viral infection has been under investigation.

OBJECTIVE

The study was aimed at providing the statistical and machine learning-based analysis to investigate the influence of climatic factors on frequency of COVID-19 confirmed cases in Iran.

METHOD

The data of confirmed cases of COVID-19 and some climatic factors related to 31 provinces of Iran between 04/03/2020 and 05/05/2020 was gathered from official resources. In order to investigate the important climatic factors on the frequency of confirmed cases of COVID-19 in all studied cities, a model based on an artificial neural network (ANN) was developed.

RESULTS

The proposed ANN model showed accuracy rates of 87.25%and 86.4%in the training and testing stage, respectively, for classification of COVID-19 confirmed cases. The results showed that in the city of Ahvaz, despite the increase in temperature, the coefficient of determination R2 has been increasing.

CONCLUSION

This study clearly showed that, with increasing outdoor temperature, the use of air conditioning systems to set a comfort zone temperature is unavoidable. Thus, the number of positive cases of COVID-19 increases. Also, this study shows the role of closed-air cycle condition in the indoor environment of tropical cities.

Assay system for mesocotyl elongation and hydrotropism of maize primary root in response to low moisture gradient

We designed and validated a test system that simulates a growth environment for Zea mays L. maize seedlings under conditions of low moisture gradient in darkness. This system allowed us to simultaneously measure mesocotyl elongation and the primary root hydrotropic response in seedlings before the emergence phase in a collection of maize hybrids. We found great variation in these two traits with statistically significant reduction of their elongations under the low moisture gradient condition that indicate the richness of maize genetic diversity. Hence, the objective of designing a new test system that evaluates the association between these underground traits with the potential use to measure other traits in maize seedlings related to early vigor was achieved.

Characterization and Comparison of Biodegradable Printed Capacitive Humidity Sensors

Flexible and biodegradable sensors are advantageous for their versatility in a range of areas from smart packaging to agriculture. In this work, we characterize and compare the performance of interdigitated electrode (IDE) humidity sensors printed on different biodegradable substrates. In these IDE capacitive devices, the substrate acts as the sensing layer. The dielectric constant of the substrate increases as the material absorbs water from the atmosphere. Consequently, the capacitance across the electrodes is a function of environmental relative humidity. Here, the performance of polylactide (PLA), glossy paper, and potato starch as a sensing layer is compared to that of nonbiodegradable polyethylene terephthalate (PET). The capacitance across inkjet-printed silver electrodes is measured in environmental conditions ranging from 15 to 90% relative humidity. The sensitivity, response time, hysteresis, and temperature dependency are compared for the sensors. The relationship between humidity and capacitance across the sensors can be modeled by exponential growth with an R² value of 0.99, with paper and starch sensors having the highest overall sensitivity. The PET and PLA sensors have response and recovery times under 5 min and limited hysteresis. However, the paper and starch sensors have response and recovery times closer to 20 min, with significant hysteresis around 100%. The PET and starch sensors are temperature independent, while the PLA and paper sensors display thermal drift that increases with temperature.

A Heuristic and Data Mining Model for Predicting Broiler House Environment Suitability

Simple Summary

The broiler housing control environment now is primarily based on the rearing temperature. The current study proposes two decision-tree models using flock-based and environmental data such as ambient temperature, air velocity, relative humidity, and ammonia concentration. Data from commercial broiler farms were collected and analyzed. An exploratory analysis employed the environmental variables, and a heuristic approach was used to develop a final dataset based on ammonia concentration’s impact on broiler production. The output models were related to dry bulb temperature, relative humidity, air velocity, and ammonia concentration arrays. The resulting trees classify the most suitable commercial broiler environment. Such variable combinations might help to improve environmental control in broiler houses.

Abstract

The proper combination of environment and flock-based variables plays a critical role in broiler production. However, the housing environment control is mainly focused on temperature monitoring during the broiler growth process. The present study developed a novel predictive model to predict the broiler (Gallus gallus domesticus) rearing conditions’ suitability using a data-mining process centered on flock-based and environmental variables. Data were recorded inside four commercial controlled environment broiler houses. The data analysis was conducted in three steps. First, we performed an exploratory and descriptive analysis of the environmental data. In the second step, we labeled the target variable that led to a specific broiler-rearing scenario depending on the age of the birds, the environmental dry-bulb temperature and relative humidity, the ammonia concentration, and the ventilation rate. The output (final rearing condition) was discretized into four categories (‘Excellent’, ‘Good’, ‘Moderate’, and ‘Inappropriate’). In the third step, we used the dataset to develop tree models using the data-mining process. The random-tree model only presented accuracy for predicting the ‘Excellent’ and ‘Moderate’ rearing conditions. The decision-tree model had high accuracy and indicated that broiler age, relative humidity, and ammonia concentration play a critical role in proper rearing conditions. Using a large amount of data allows the data-mining approach to building up ‘if–then’ rules that indicate suitable environmental control decision-making by broiler farmers.

Exposure of Ophthalmologists to Patients' Exhaled Droplets in Clinical Practice: A Numerical Simulation of SARS-CoV-2 Exposure Risk

Background: Lack of quantification of direct and indirect exposure of ophthalmologists during ophthalmic diagnostic process makes it hard to estimate the infectious risk of aerosol pathogen faced by ophthalmologists at working environment. Methods: Accurate numerical models of thermal manikins and computational fluid dynamics simulations were used to investigate direct (droplet inhalation and mucosal deposition) and indirect exposure (droplets on working equipment) within a half-minute procedure. Three ophthalmic examination or treatment scenarios (direct ophthalmoscopic examination, slit-lamp microscopic examination, and ophthalmic operation) were selected as typical exposure distance, two breathing modes (normal breathing and coughing), three levels of ambient RH (40, 70, and 95%) and three initial droplet sizes (50, 70, and 100 μm) were considered as common working environmental condition. Results: The exposure of an ophthalmologist to a patient's expiratory droplets during a direct ophthalmoscopic examination was found to be 95 times that of a person during normal interpersonal interaction at a distance of 1 m and 12.1, 8.8, and 9.7 times that of an ophthalmologist during a slit-lamp microscopic examination, a surgeon during an ophthalmic operation and an assistant during an ophthalmic operation, respectively. The ophthalmologist's direct exposure to droplets when the patient cough-exhaled was ~7.6 times that when the patient breath-exhaled. Compared with high indoor RH, direct droplet exposure was higher and indirect droplet exposure was lower when the indoor RH was 40%. Conclusion: During the course of performing ophthalmic examinations or treatment, ophthalmologists typically face a high risk of SARS-CoV-2 infection by droplet transmission.

Screening of Particulate Matter Reduction Ability of 21 Indigenous Korean Evergreen Species for Indoor Use

The formation and pollution of particulate matter (PM), a side effect of rapid industrialization and urbanization, is considered a global issue. However, various plant species are able to effectively capture and reduce atmospheric PM concentrations. We investigated the indoor growth and morphology of 21 indigenous Korean evergreen species at low light intensities to ascertain their ability to reduce PM of aerosol particles in a closed acrylic chamber. The decrease in PM mass concentration differed significantly across species, with a significant correlation (8 h; p < 0.001). The reduction in the mass concentration of PM differed with particle size and across species. The highest reduction of PM_2.5 occurred after 8 h with Dryopteris lacera (86.8%), Ilex × wandoensis (84.9%), Machilus thunbergii (84.3%), and Rhododendron brachycarpum (84.0%). Reduction of PM₁₀ after 8 h was highest with Cephalotaxus harringtonii (98.3%), I. × wandoensis (98.5%), M. thunbergii (98.5%), and R. brachycarpum (98.3%). Plant morphological characteristics (category, plant height, leaf shape, leaf area) and relative humidity were closely related to the decrease in PM mass concentration. In conclusion, our findings can be used to identify Korean plant species that can reduce PM concentration and are suitable for indoor use.

Insight into Canary Island pine physiology provided by stable isotope patterns of water and plant tissues along an altitudinal gradient

The Canary Islands, an archipelago east of Morocco's Atlantic coast, present steep altitudinal gradients covering various climatic zones from hot deserts to subalpine Mediterranean, passing through fog-influenced cloud forests. Unlike the majority of the Canarian flora, Pinus canariensis C. Sm. ex DC. in Buch grow along most of these gradients, allowing the study of plant functioning in contrasting ecosystems. Here we assess the water sources (precipitation, fog) of P. canariensis and its physiological behavior in its different natural environments. We analyzed carbon and oxygen isotope ratios of water and organics from atmosphere, soil and different plant organs and tissues (including 10-year annual time series of tree-ring cellulose) of six sites from 480 to 1990 m above sea level on the Canary Island La Palma. We found a decreasing δ18O trend in source water that was overridden by an increasing δ18O trend in needle water, leaf assimilates and tree-ring cellulose with increasing altitude, suggesting site-specific tree physiological responses to relative humidity. Fog-influenced and fog-free sites showed similar δ13C values, suggesting photosynthetic activity to be limited by stomatal closure and irradiance at certain periods. In addition, we observed an 18O-depletion (fog-free and timberline sites) and 13C-depletion (fog-influenced and fog-free sites) in latewood compared with earlywood caused by seasonal differences in: (i) water uptake (i.e., deeper ground water during summer drought, fog water frequency and interception) and (ii) meteorological conditions (stem radial growth and latewood δ18O correlated with winter precipitation). In addition, we found evidence for foliar water uptake and strong isotopic gradients along the pine needle axis in water and assimilates. These gradients are likely the reason for an unexpected underestimation of pine needle water δ18O when applying standard leaf water δ18O models. Our results indicate that soil water availability and air humidity conditions are the main drivers of the physiological behavior of pine along the Canary Island's altitudinal gradients.

Lightning Behaviour during the COVID-19 Pandemic

Background COVID-19 has drastically dampened human activities since early 2020. Studies have shown that this has resulted in changes in air temperature and humidity. Since lightning activities are dependent on air temperature and humidity, this study is conducted to evaluate the correlation between the intensity of lightning activities with the atmospheric changes, and investigates the changes, in lightning activities due to atmospheric changes during the COVID-19 pandemic. Methods The hypothesis was tested through a t-test and Pearson's correlation study. The variation trend of lightning strikes count (LSC) in Europe and Oceania during the five months COVID-19 lockdown period (March - July) compared to the same period in the previous five years from 2015 to 2019 is investigated. Results Statistical analysis shows the LSC in Europe and Oceania during the lockdown period dropped significantly by more than 50% and 44% respectively compared to the same period in previous five years. Furthermore, LSC was found to be positively correlated with air temperature and relative humidity in Europe. However, in Oceania, LSC seems to be only positively correlated with air temperature but negatively correlated with relative humidity. Conclusions This study seems to suggest that lightning activities have significantly changed during this pandemic due to reduction in human activities.

Lightning Behaviour during the COVID-19 Pandemic

Background COVID-19 has drastically dampened human activities since early 2020. Studies have shown that this has resulted in changes in air temperature and humidity. Since lightning activities are dependent on air temperature and humidity, this study is conducted to evaluate the correlation between the intensity of lightning activities with the atmospheric changes, and investigates the changes, in lightning activities due to atmospheric changes during the COVID-19 pandemic. Methods The hypothesis was tested through a t-test and Pearson's correlation study. The variation trend of lightning strikes count (LSC) in Europe and Oceania during the five months COVID-19 lockdown period (March - July) compared to the same period in the previous five years from 2015 to 2019 is investigated. Results Statistical analysis shows the LSC in Europe and Oceania during the lockdown period dropped significantly by more than 50% and 44% respectively compared to the same period in previous five years. Furthermore, LSC was found to be positively correlated with air temperature and relative humidity in Europe. However, in Oceania, LSC seems to be only positively correlated with air temperature but negatively correlated with relative humidity. Conclusions This study seems to suggest that lightning activities have significantly changed during this pandemic due to reduction in human activities.

Lightning Behaviour during the COVID-19 Pandemic

Background COVID-19 has drastically dampened human activities since early 2020. Studies have shown that this has resulted in changes in air temperature and humidity. Since lightning activities are dependent on air temperature and humidity, this study is conducted to evaluate the correlation between the intensity of lightning activities with the atmospheric changes, and investigates the changes, in lightning activities due to atmospheric changes during the COVID-19 pandemic. Methods The hypothesis was tested through a t-test and Pearson's correlation study. The variation trend of lightning strikes count (LSC) in Europe and Oceania during the five months COVID-19 lockdown period (March - July) compared to the same period in the previous five years from 2015 to 2019 is investigated. Results Statistical analysis shows the LSC in Europe and Oceania during the lockdown period dropped significantly by more than 50% and 44% respectively compared to the same period in previous five years. Furthermore, LSC was found to be positively correlated with air temperature and relative humidity in Europe. However, in Oceania, LSC seems to be only positively correlated with air temperature but negatively correlated with relative humidity. Conclusions This study seems to suggest that lightning activities have significantly changed during this pandemic due to reduction in human activities.

Relative Humidity Predicts Day-to-Day Variations in COVID-19 Cases in the City of Buenos Aires

Possible links between the transmission of COVID-19 and meteorology have been investigated by comparing positive cases across geographical regions or seasons. Little is known, however, about the degree to which environmental conditions modulate the daily dynamics of COVID-19 spread at a given location. One reason for this is that individual waves of the disease typically rise and decay too sharply, making it hard to isolate the contribution of meteorological cycles. To overcome this shortage, we here present a case study of the first wave of the outbreak in the city of Buenos Aires, which had a slow evolution of the caseload extending along most of 2020. We found that humidity plays a prominent role in modulating the variation of COVID-19 positive cases through a negative-slope linear relationship, with an optimal lag of 9 days between the meteorological observation and the positive case report. This relationship is specific to winter months, when relative humidity predicts up to half of the variance in positive case count. Our results provide a tool to anticipate possible local surges in COVID-19 cases after events of low humidity. More generally, they add to accumulating evidence pointing to dry air as a facilitator of COVID-19 transmission.

The Correlation Between COVID-19 Activities and Climate Factors in Different Climate Types Areas

OBJECTIVE

To investigate the epidemiological characteristics of human infection with corona virus disease 2019 (COVID-19) in Moscow, Lima, Kuwait, and Singapore to analyze the effects of climate factors on the incidence of COVID-19.

METHODS

Collect the daily incidence of COVID-19 and related climate data in four areas, construct a negative binomial regression model, and analyze the correlation between the incidence of COVID-19 and meteorological factors.

RESULTS

AH was the climate factor affecting the incidence of COVID-19 in Moscow, Lima, and Singapore; Ta and RH were the climate factors affecting the incidence of COVID-19 in Kuwait.

CONCLUSIONS

The incidence of COVID-19 in four areas were all associated with the humidity, and climate factors should be taken into consideration when epidemic prevention measures are taken, and environment humidification may be a feasible approach to decrease COVID-19 virus transmission.

Effect of Relative Humidity on the Electrospinning Performance of Regenerated Silk Solution

Recently, the electrospun silk web has been intensively studied in terms of its biomedical applications, including tissue engineering scaffolds, due to its good biocompatibility, cytocompatibility, and biodegradability. In this study, the effect of relative humidity (RH) conditions on the morphology of electrospun silk fiber and the electrospinning production rate of silk solution was examined. In addition, the effect of RH on the molecular conformation of electrospun silk web was examined using Fourier transform infrared (FTIR) spectroscopy. As RH was increased, the maximum electrospinning rate of silk solution and fiber diameter of the resultant electrospun silk web were decreased. When RH was increased to 60%, some beads were observed, which showed that the electrospinnability of silk formic acid solution deteriorated with an increase in RH. The FTIR results showed that electrospun silk web was partially β-sheet crystallized and RH did not affect the molecular conformation of silk.

Review on Interfacial Bonding Mechanism of Functional Polymer Coating on Glass in Atomistic Modeling Perspective

Atomistic modeling methods are successfully applied to understand interfacial interaction in nanoscale size and analyze adhesion mechanism in the organic-inorganic interface. In this paper, we review recent representative atomistic simulation works, focusing on the interfacial bonding, adhesion strength, and failure behavior between polymer film and silicate glass. The simulation works are described under two categories, namely non-bonded and bonded interaction. In the works for non-bonded interaction, three main interactions, namely van der Waals interaction, polar interaction, and hydrogen bonds, are investigated, and the contributions to interfacial adhesion energy are analyzed. It is revealed that the most dominant interaction for adhesion is hydrogen bonding, but flexibility of the polymer film and modes of adhesion measurement test do affect adhesion and failure behavior. In the case of bonded interactions, the mechanism of covalent silane bond formation through condensation and hydrolysis process is reviewed, and surface reactivity, molecular density, and adhesion properties are calculated with an example of silane functionalized polymer. Besides interfacial interactions, effects of external conditions, such as surface morphology of the glass substrate and relative humidity on the adhesion and failure behavior, are presented, and modeling techniques developed for building interfacial system and calculating adhesion strengths are briefly introduced.

Associations of indoor carbon dioxide concentrations, air temperature, and humidity with perceived air quality and sick building syndrome symptoms in Chinese homes

The indoor environment influences occupants' health. From March 1, 2018, to February 28, 2019, we continuously monitored indoor temperature (T), relative humidity (RH), and CO₂ concentration in bedrooms via an online system in 165 residences that covered all five climate zones of China. Meanwhile, we asked one specific occupant in each home to complete questionnaires about perceived air quality and sick building syndrome (SBS) symptoms at the end of each month. Higher CO₂ concentration was significantly associated with a higher percentage of perceived stuffy odor and skin SBS symptoms. Higher relative humidity was associated with higher percentage of perceived moldy odor and humid air, while lower RH was associated with a higher percentage of perceived dry air. Occupants who lived in residences with high RH were less likely to have mucosal and skin SBS symptoms (adjusted odds ratio (AOR): 0.73-0.78). However, the benefit of high humidity for perceived dry air and skin dryness symptoms is weaker if there is a high CO₂ concentration level.

Not Only a Formulation: The Effects of Pickering Emulsion on the Entomopathogenic Action of Metarhizium brunneum

Growing global population and environmental concerns necessitate the transition from chemical to eco-friendly pest management. Entomopathogenic fungi (EPF) are rising candidates for this task due to their ease of growing, broad host range and unique disease process, allowing EPF to infect hosts directly through its cuticle. However, EPF’s requirement for high humidity negates their integration into conventional agriculture. To mitigate this problem, we formulated Metarhizium brunneum conidia in an oil-in-water Pickering emulsion. Conidia in aqueous and emulsion formulations were sprayed on Ricinus communis leaves, and Spodoptera littoralis larvae were introduced under low or high humidity. The following were examined: conidial dispersion on leaf, larval mortality, conidial acquisition by larvae, effects on larval growth and feeding, and dynamic of disease progression. Emulsion was found to disperse conidia more efficiently and caused two-fold more adhesion of conidia to host cuticle. Mortality from conidia in emulsion was significantly higher than other treatments reaching 86.5% under high humidity. Emulsion was also found to significantly reduce larval growth and feeding, while conferring faster fungal growth in-host. Results suggest that a Pickering emulsion is able to improve physical interactions between the conidia and their surroundings, while weakening the host through a plethora of mechanisms, increasing the chance of an acute infection.

Association of temperature and relative humidity with the growth rate of the coronavirus disease 2019 epidemic

The effects of temperature and relative humidity on the growth of coronavirus disease 2019 (COVID-19) remain unclear. Data on the COVID-19 epidemic that were analyzed in this study were obtained from the official websites of the National Health Commission of China and the Health Commissions of 31 provinces in China. From January 26 to February 25, 2020, the cumulative number of confirmed COVID-19 cases in each region was counted daily using data from our database. Curve fitting of daily scatter plots of the relationship between epidemic growth rate (GR) with average temperature (AT) and average relative humidity (ARH) was conducted using the loess method. The heterogeneity across days and provinces was calculated to assess the necessity of using a longitudinal model. Fixed-effect models with polynomial terms were developed to quantify the relationship between variations in the GR and AT or ARH. An increased AT markedly reduced the GR when the AT was lower than -5°C, the GR was moderately reduced when the AT ranged from -5°C to 15°C, and the GR increased when the AT exceeded 15°C. ARH increased the GR when it was less than 72% and reduced the GR when it exceeded 72%. The temperature and relative humidity curves were not linearly associated with the GR of COVID-19. The GR was moderately reduced when the AT ranged from -5°C to 15°C. When the AT was lower or higher than -5°C to 15°C, the GR of COVID-19 increased. An increased ARH increased the GR when the ARH was lower than 72% and reduced the GR when the ARH exceeded 72%.

Severe acute respiratory syndrome coronavirus-2 medical solid waste treatment: A need for efficient and effective strategies in low-resourced settings

Understanding infections related to handling healthcare waste products is of critical importance and the application of simple and low-cost strategies remain a priority in low-income and middle-income countries to protect healthcare workers. We examined the potential effect of relative humidity (RH), air temperature and ultraviolet irradiation (UI) to establish an efficient and effective way to facilitate disposal of medical waste. Literature is emerging on the effect of high RH and high temperature, which would increase airborne mass deposition and decrease the viability of viruses in both airborne particles and on surfaces. On the other hand, severe acute respiratory syndrome coronavirus-2 has been proven to be susceptible to UI when suspended in air like other coronaviruses. An innovative approach utilizing environmental conditions might represent an effective and efficient way to ensure better and sustainable protection of the healthcare workers in low-resourced settings.

Large-Scale Spraying of Roads with Water Contributes to, Rather Than Prevents, Air Pollution

Spraying roads with water on a large scale in Chinese cities is one of the supplementary precaution or mitigation actions implemented to control severe air pollution events or heavy haze-fog events in which the mechanisms causing them are not yet fully understood. These air pollution events were usually characterized by higher air humidity. Therefore, there may be a link between this action and air pollution. In the present study, the impact of water spraying on the PM_2.5 concentration and humidity in air was assessed by measuring chemical composition of the water, undertaking a simulated water spraying experiment, measuring residues and analyzing relevant data. We discovered that spraying large quantities of tap or river water on the roads leads to increased PM_2.5 concentration and humidity, and that daily continuous spraying produces a cumulative effect on air pollution. Spraying the same amount of water produces greater increases in humidity and PM_2.5 concentration during cool autumn and winter than during hot summer. Our results demonstrate that spraying roads with water increases, rather than decreases, the concentration of PM_2.5 and thus is a new source of anthropogenic aerosol and air pollution. The higher vapor content and resultant humidity most likely create unfavorable meteorological conditions for the dispersion of air pollution in autumn and winter with low temperature.

Humidity Effects on Domain Structure and Polarization Switching of Pb(Zn1/3Nb2/3)O3-x%PbTiO3 (PZN-x%PT) Single Crystals

The effect of relative humidity on the domain structure imaging and polarization switching process of Pb(Zn1/3Nb2/3)O3-x%PbTiO3 (PZN-x%PT) ferroelectric single crystals has been investigated by means of the piezoresponse force microscopy (PFM) and piezoresponse force spectroscopy (PFS) techniques. It was found that the PFM amplitude increases with the relative humidity, and that the ferroelectric hysteresis loops at different relative humidity levels show that the coercive bias decreases with the increase in relative humidity. These observed phenomena are attributed to the existence of the water layer between the probe tip and the sample surface in a humid atmosphere, which could affect the effect of the electric field distribution and screening properties at the ferroelectric sample surface. These results provide a better understanding of the water adsorption phenomena at the nanoscale in regard to the fundamental understanding of ferroelectrics' properties.

Improving the Autogenous Self-Sealing of Mortar: Influence of Curing Condition

With the construction of projects under severe environments, new and higher requirements are put forward for the properties of concrete, especially the autogenous self-sealing property, which is greatly affected by the curing environment and the state of the water. Herein, six types of curing conditions, including in air with a relative humidity of 30%, 60%, and 95%; flowing water; wet-dry cycles; and static water, are designed to investigate the autogenous self-sealing of mortar under different curing conditions. The results showed that the self-sealing ratios are higher than 60% and the cracks are closed for the mortar undergoing the wet-dry cycles and the static water. However, the self-sealing ratios of mortar are lower than 10% and the cracks are almost unchanged when the mortar is cured in the air with a relative humidity (RH) of 30% and 60%. The static liquid water is more conducive to the continued hydration of cement and the formation of CaCO₃ than the flowing water. The research provides guidance for the design of concrete and the improvement of autogenous self-sealing when the concrete serves in different environments.

Impact of environmental temperature and relative humidity on spread of COVID-19 infection in India: a cross-sectional time-series analysis

Purpose: Coronavirus disease 2019 (COVID-19) has become a serious public health problem worldwide. This study sought to examine the associations of daily average temperature (AT) and relative humidity (ARH) with the percent increase in COVID-19 cases. Methods: Daily confirmed cases and meteorological factors in 38 districts of India were collected between 1^st April 2020 to 30^th April 2020. Taking a 5-day time lag of average values of the variables and multiple days-samples, we ran multiple models and performed appropriate hypothesis tests to decide the single preferred model for each sample data. Suitable fixed effects (FE) and random effects (RE) models with cluster-robust standard errors were applied to quantify the district-specific associations of meteorological and other variables with COVID-19 cases. Results: All FE models revealed that every one-degree rise in AT led to a decrease in 3.909 points (on average) in percent increase in COVID-19 cases. All RE models showed that with one unit increase in the malaria annual parasite index, there was a significant increase in 10.835 points (on average) in percent increase in COVID-19 cases. In both FE and RE models, ARH was found to be negatively associated with a percent increase in COVID-19 cases, although in half of these models the association was statistically insignificant. Conclusion: Our results indicate that mean temperature, mean relative humidity, and malaria endemicity might have an essential role in the stability and transmissibility of the 2019 novel coronavirus.

Impact of Meteorological Conditions on the Dynamics of the COVID-19 Pandemic in Poland

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the novel coronavirus. The role of environmental factors in COVID-19 transmission is unclear. This study aimed to analyze the correlation between meteorological conditions (temperature, relative humidity, sunshine duration, wind speed) and dynamics of the COVID-19 pandemic in Poland. Data on a daily number of laboratory-confirmed COVID-19 cases and the number of COVID-19-related deaths were gatheredfrom the official governmental website. Meteorological observations from 55 synoptic stations in Poland were used. Moreover, reports on the movement of people across different categories of places were collected. A cross-correlation function, principal component analysis and random forest were applied. Maximum temperature, sunshine duration, relative humidity and variability of mean daily temperature affected the dynamics of the COVID-19 pandemic. An increase intemperature and sunshine hours decreased the number of confirmed COVID-19 cases. The occurrence of high humidity caused an increase in the number of COVID-19 cases 14 days later. Decreased sunshine duration and increased air humidity had a negative impact on the number of COVID-19-related deaths. Our study provides information that may be used by policymakers to support the decision-making process in nonpharmaceutical interventions against COVID-19.

Direct surface wetting sprinkler system to reduce the use of evaporative cooling pads in meat chicken production: indoor thermal environment, water usage, litter moisture content, live market weights, and mortalities

An overhead sprinkler system that directly applies water onto meat chickens in tunnel ventilated houses was evaluated and compared with a conventional evaporative cooling pad system at 2 commercial farms in south-eastern Queensland, Australia. The sprinkler system was used to reduce the use of evaporative cooling pads as the primary cooling system but not replace evaporative cooling pads altogether. The sprinkler system used low water pressure and comprised evenly spaced sprinklers and a programmable controller. Water was applied intermittently based on house temperature and a temperature program that was related to bird age. The study was conducted over 6 sequential grow-outs during a 1-year period. Air temperature, relative humidity, litter moisture content, cooling water usage, live market weight, and mortality were assessed during the study. The effect of sprinklers on these measured parameters was complicated by interactions with farm, batch, bird age, and time of day. We found that, in general, houses with combined sprinkler and evaporative cooling pad systems used less water, while having similar litter moisture content, live market weight, and mortality compared with control houses that were fitted with conventional evaporative cooling pads. When evaporative cooling was required, sprinkler houses had warmer air temperature but lower relative humidity than the control houses. Bird comfort due to the direct cooling effect of water evaporating off the birds was not directly assessed during this study but was inferred from thermal camera images and from live weight and mortality data. This was the first study in Australia involving this sprinkler system, and we suggest that the sprinkler system design and operation may require some adaptation to better suit Australian poultry house design and climatic conditions, including the need for additional sprinklers to improve coverage, lower set-point temperatures, and altering sprinkler spacing to suit ceiling baffle curtains (if fitted).