Average Daytime Research Articles

BLOOD PRESSURE SURGE DURING THE EARTHQUAKE IN CITY OF PETRINJA, BANIJA REGION IN CROATIA

Objective: Stress is known to contribute to other well-known environmental risk factors to hypertension leading to sympathetic overactivity. While usual environmental factors can be easily measured, exposure to stress is difficult to objectivize, especially during catastrophic events which are recognized as main stressors. There are several reports about earthquakes, blood pressure (BP) and cardiovascular events. Design and method: We are reporting a case on ambulatory blood pressure monitoring (ABPM) in 42-year-old women during Croatian earthquake. Results: A 42-year-old women with multiple genetic and environmental risk factors for hypertension was evaluated for secondary hypertension, and adult autosomal polycystic kidney disease was diagnosed. Kidney function was normal and there were no signs of target organ damage. She was treated with a fixed dose combination perindopril/amlodipine 4/5 mg (morning). ABPM revealed mildly uncontrolled systolic-diastolic hypertension with extreme nocturnal dip. Average 24-hour, daytime and nighttime BP values were 130±20,4/79±19,9 mmHg, 137±16,2 /85±17,9 mmHg, 100±11,8 /55±11,7 mmHg, respectively. White coat effect was present, and masked hypertension was ruled out. Average 24-hour, daytime and nighttime heart rate were: 88b/min, 93b/min, and 79b/min. A significant surge in BP and heart rate (200/130 mmHg,140 b/min) was recorded at 12:30 p.m. exactly at the time when earthquake occurred in city Petrinja, also felt in Zagreb city. The earthquake was clearly stated in the blood pressure diary (Figure 1). Conclusions: Although chronic stress is emphasized to affect human health more than acute, catastrophic events such as earthquakes can have deleterious effect such as enormous elevation of BP. It is necessary to have strategies for BP management in disaster-related diseases to prevent organ damage.

NIGHTTIME BLOOD PRESSURE ASSESSED USING HOME MONITORING IN HYPERTENSIVE PATIENTS WITH TYPE 2 DIABETES/PREDIABETES: ASSOCIATION AND AGREEMENT WITH AMBULATORY MONITORING

Objective: To investigate the agreement between nighttime blood pressure (BP) measurements using home (HBPM) or ambulatory BP monitors (ABPM) in individuals with hypertension and type 2 diabetes mellitus (DM2) or prediabetes. Design and method: Adults with hypertension (treated or untreated) and DM2 or prediabetes underwent ABPM (measurements at 20 minutes intervals, Microlife WatchBP03) and HBPM (duplicate morning/evening measurements for 7 days, 3 nights with 3 measurements/night, Microlife WatchBP Home-N). Nighttime hypertension was defined as BP >= 120/70 mmHg (systolic/diastolic). Nighttime BP dipping was calculated as the ratio of nighttime BP decline to the daytime levels. Individuals with nighttime BP dip (systolic and/or diastolic) <10% were classified as non-dippers. Results: Data from 113 participants were analyzed (mean age [SD] 65±9.1 years, 67% men, body mass index 30.7±4.8 kg/m2, 84% with DM2, 22% cardiovascular disease, 94% treated hypertension). Average daytime HBPM was 129.2±13.2/73.3±7.8 mmHg and ABPM 126.7±12.1/72.5±7.4 mmHg (systolic/diastolic, p<0.01/p=NS), whilst nighttime HBPM was 115.3±13.1/63.6±7.6 mmHg and ABPM 113.9±13.4/63±7.1 mmHg (systolic/diastolic, p<0.05/p=NS). Strong correlation was observed between HBPM and ABPM levels: daytime r=0.71/0.74 and nighttime 0.86/0.78, systolic/diastolic, p<0.01)]. Good agreement was also found between ABPM and HBPM in diagnosing nighttime hypertension (81%/90%; kappa=0.55/0.70 systolic/diastolic). Among the participants, 32%/31% were classified as non-dippers (HBPM/ABPM, p=NS), with a 74% agreement (kappa=0.41) in detecting non-dippers. Conclusions: These preliminary findings indicate that in individuals with hypertension and DM2 or prediabetes, nighttime BP assessed by a novel home monitor is feasible and shows strong correlation and satisfactory agreement with reference ABPM in detecting nighttime hypertension and non-dipping.

Passive daytime radiative cooling composite films with super-amphiphobic, friction-resistant and flame-retardant properties

Ensuring prolonged performance is a challenge in promoting passive daytime radiative cooling materials (PDRCMs) for addressing energy depletion. A single-layer inlay-structured passive daytime radiative cooling composite film (PDRCCF) was introduced with hexagonal boron nitride (h-BN) in polydimethylsiloxane (PDMS) and randomly semi-embedded fluorination-modified barium sulfate (M-BaSO4) particles on the substrate surface. The optimal sample demonstrated high average reflectivity of 94.73% in the solar spectrum (SS), average emissivity of 95.96% in the mid-infrared wavelength range (MIWR) (2.5–25 μm) and average daytime temperature drop of 4.21°C in cloudy weather, and also exhibited super-amphiphobic, friction-resistant and flame-retardant properties due to the h-BN and M-BaSO4 particles. This work offers a significant strategy for advancing PDRCMs.

Abiotic and biotic factors influencing small-scale corn production along a shade spectrum in arid urban agriculture settings.

Urban agriculture may be an avenue to help alleviate strain on the global production of staple crops like corn (Zea mays), but significant knowledge gaps exist regarding the optimization of staple crop production in urban settings, and especially in arid urban settings where different challenges exist for crop success. We sought to assess abiotic and biotic factors that impact sweet corn production in six arid urban agricultural plots with varying levels of shade stress, a known inhibitor of corn production. Corn successfully reached maturity in 50% of the studied plots (n = 18). Microbial richness and diversity were uniformly high in all plot soils and not indicated as a hinderance to corn production nor correlated with corn success. Multiple corn success metrics were positively correlated with average daytime light intensity (r = 0.74 to 0.84) and soil organic matter (r = 0.77 to 0.89), suggesting that these factors are critical aspects of successful corn production. In plots that did not receive optimal light exposure, exceptional soil health and morning vs afternoon sun exposure offset at least some degree of shade stress in these arid urban environments. Corn success metrics were negatively correlated with soil calcium, magnesium, sodium and sulfate (r = -0.71 to -0.90), suggesting that minimizing or mitigating the buildup of salt constituents in soils is critical for successful corn production. Optimizing staple crop production in arid urban agricultural settings supports food chain stability and social and economic security of local communities. This work suggests abiotic and biotic drivers of corn success which can be utilized for crop optimization in these environments.

The potential of urban trees to reduce heat-related mortality in London

Increasing temperatures and more frequent heatwave events pose threats to population health, particularly in urban environments due to the urban heat island (UHI) effect. Greening, in particular planting trees, is widely discussed as a means of reducing heat exposure and associated mortality in cities. This study aims to use data from personal weather stations (PWS) across the Greater London Authority to understand how urban temperatures vary according to tree canopy coverage and estimate the heat-health impacts of London’s urban trees. Data from Netatmo PWS from 2015–2022 were cleaned, combined with official Met Office temperatures, and spatially linked to tree canopy coverage and built environment data. A generalized additive model was used to predict daily average urban temperatures under different tree canopy coverage scenarios for historical and projected future summers, and subsequent health impacts estimated. Results show areas of London with higher canopy coverage have lower urban temperatures, with average maximum daytime temperatures 0.8 °C and minimum temperatures 2.0 °C lower in the top decile versus bottom decile canopy coverage during the 2022 heatwaves. We estimate that London’s urban forest helped avoid 153 heat attributable deaths from 2015–2022 (including 16 excess deaths during the 2022 heatwaves), representing around 16% of UHI-related mortality. Increasing tree coverage 10% in-line with the London strategy would have reduced UHI-related mortality by a further 10%, while a maximal tree coverage would have reduced it 55%. By 2061–2080, under RCP8.5, we estimate that London’s current tree planting strategy can help avoid an additional 23 heat-attributable deaths a year, with maximal coverage increasing this to 131. Substantial benefits would also be seen for carbon storage and sequestration. Results of this study support increasing urban tree coverage as part of a wider public health effort to mitigate high urban temperatures.

Energy partitioning over an irrigated vineyard in arid northwest China: Variation characteristics, influence degree, and path of influencing factors

In this study, a two-year experiment in an irrigated vineyard was conducted to investigate the variations in energy fluxes (net radiation, Rn; latent heat flux, LE; sensible heat flux, H; and soil heat flux, G) and quantify the influence of arid advection and environmental factors (vapor pressure deficit (VPD), Rn, air temperature, wind speed, precipitation, and volumetric soil water content) on energy partitioning in arid Northwest China. For the diurnal variation, the peak values of the energy fluxes appeared at approximately 14:00, except for G (which appeared at approximately 16:00). LE was the main consumer of daytime (Rn>0) energy during the growing season (average LE/(Rn–G) was 87% and 89% in the two years), even during the shooting and leaf-fall stages. Arid advection, which affects energy partitioning mainly by increasing atmospheric evaporative demand and providing heat energy, contributed 6–60% and 1–56% of the average daytime LE during the two growing seasons, especially at the fruiting stage. Moreover, advection accounted for more than half of average daytime energy imbalances. We found that the arid advection induced by irrigation could be attenuated by selecting a reasonable irrigation time. According to the structural equation modeling (SEM) analysis, Rn had the strongest direct and positive regulation effect on LE at the half-hourly and daily scales, indicating that LE was limited by energy rather than water in the study area. The influence of Rn on LE gradually weakened with an increase in the time scale, whereas the effect of VPD increased, which may have been due to the smaller time-lag effect between VPD and LE. The diurnal variations in LE at approximately 08:00–19:30 and 19:30–08:00 were mainly controlled by the direct positive effects of Rn and VPD, respectively. The results obtained in this study will provide a better understanding of surface processes and help improve water resource management in arid agricultural areas.

Peculiarities of the daily profile of blood pressure and heart activity in patients with arrhythmias depending on the severity of cognitive disordersPeculiarities of the daily profile of blood pressure and heart activity in patients with arrhythmias depending on the severity of cognitive disorders

Background. The purpose of our work was to reveal the dependence of changes in the cognitive sphere on the peculiarities of the daily profile of blood pressure (BP) and heart activity in patients with arrhythmias. Materials and methods. We examined 139 patients with different clinical forms of arrhythmias. All of them underwent extended neuropsychological testing, a study of the daily BP profile and heart activity. Hemodynamic status was assessed by daily BP and ECG monitoring. Average daily, average daytime and nighttime systolic (SBP), diastolic blood pressure (DBP) and heart rate (HR) were evaluated. The analysis of spectral indicators of heart rate variability was performed to assess the state of the autonomic nervous system. Correlations of hemodynamic indicators with the results of neuropsychological testing were determined. Results. In patients with cognitive disorders (CD), there was an increase in SBP in all periods of the day, most pronounced in patients with moderate CD (p = 0.049). In patients with mild CD and without CD, there were no significant intergroup differences in the level of average daily, daytime and night SBP, DBP and pulse pressure (p > 0.05). Patients with moderate CD had significantly higher SBP and time index of SBP at the expense of average daytime and average night values of these indicators compared to those without CD (p < 0.05). During the active period of the day, time index of DBP was significantly higher in patients with moderate CD (p = 0.002) who also had an increase in average daily, daytime and night SBP variability compared to participants without CD (p = 0.041). The differences between the groups were not significant in terms of DBP variability (р = 0.07). In 61 (54 %) patients with CD, non-dipper SBP prevailed in the structure of disorders of the daily BP profile, with the highest indicators in moderate CD (55.6 %). The presence of adverse daily DBP profiles — night-peaker (6.2 %) and over-dipper (8.8 %), which prevailed in patients with moderate CD, is hidden behind normal indicators of the daily BP index. Increased average SBP24 (odds ratio (OR) = 3.26, 95% confidence interval (CI): 1.45–5.35, p < 0.001), DBP24 (OR = 3.06, 95% CI: 1.41–4.79, p < 0.001), average HR24 (OR = 2.67, 95% CI: 1.32–4.14, p < 0.001), average SBP24 variability (OR = 2.13, 95% CI: 1.11–3.32, p < 0.001) are the main factors of central hemodynamic disorders that increase the risk of developing CD in patients with arrhythmias. Conclusions. The identified associations between cognitive dysfunction, indicators of daily BP monitoring and heart activity are important in the context of their comprehensive accounting for optimizing an individualized approach to patient management and predicting the development of CD.

Yield Gap Analysis of Super High-Yielding Rice (>15 t ha−1) in Two Ecological Regions

Super high-yielding rice (SHYR) (>15 t ha−1) plays a crucial role in global food production and security. We hypothesized that the external environment of different ecological regions could improve biomass accumulation in different periods and thus increase the rice yield. Two SHYR varieties, i.e., Xiangliangyou900 (XLY900) and Yliangyou900 (YLY900), were cultivated in the YONGSHENG and LONGHUI ecoregions, China. The results indicated that the average yield of the two SHYRs in the LONGHUI ecological region was 15.27–15.45 t ha−1 and 18.81–20.10 t ha−1 in YONGSHENG. The high grain yield in the YONGSHENG ecoregion was mainly due to the increased number of spikelets per panicle, crop growth rate, and total biomass during the transplanting–heading stage (TP-HS) and heading–maturity stage (HS-MS), and harvest index. The yield of SHYR was significantly correlated with external environment conditions, i.e., average minimum temperature, average daytime, and night-time temperature, and average daily temperature at the TP-HS, HS-MS, and transplanting–maturity (TP-MS) stages. The rice yield was significantly and positively correlated with the cumulative daily radiation. Therefore, it can be concluded that the final yield of super high-yield rice is closely related to the utilization of temperature and radiation resources during the growth process in the ecological environment.

Objectively measured the impact of ambient air pollution on physical activity for older adults

BackgroundAir pollution poses a significant health risk to the human population, especially for vulnerable groups such as the elderly, potentially discouraging their engagement in physical activity. However, there is a lack of sufficient objective and longitudinal data in current research on how air pollution affects physical activity among older adults. With these gaps, we aimed to explore the relationship between air pollution and objective measurement-based physical activity among older adults by engaging in a longitudinal study design.MethodsA total of 184 older adults were recruited from three cities with varying levels of air quality. Mean daily minutes of physical activity were measured with 7 consecutive days of accelerometer monitoring (ActiGraph GT3X-BT). Corresponding air pollution data including daily PM2.5 (µg/m3), PM10 (µg/m3) and air quality index (AQI) were sourced from the China National Environmental Monitoring Centre at monitor locations close to older adults’ addresses. Associations between air quality and physical activity were estimated using a fixed effect model, adjusting for average daytime temperature, rain, age and weight.ResultsAQI and PM2.5 were observed to exhibit significant, inverse, and linear associations with mean daily walk steps, minutes of light physical activity (LPA), moderate physical activity (MPA) and moderate-to-vigorous physical activity (MVPA) in the single variable models. A one-level increase in AQI corresponded to a decline in 550.04 steps (95% [CI] = -858.97, -241.10; p < 0.001), 10.43 min (95% [CI] = -17.07, -3.79; p < 0.001), 4.03 min (95% [CI] = -7.48, -0.59; p < 0.001) and 4.16 min (95% [CI] = -7.77, -0.56; p < 0.001) in daily walking steps, LPA, MPA, and MVPA, respectively. A one-level increase in PM2.5 correlated with a decline in daily walk steps, LPA, MPA and MVPA by 361.85 steps (95% [CI] = -516.53, -207.16; p < 0.001), 8.97 min (95% [CI] = -12.28, -5.66; p < 0.001), 3.73 min (95% [CI] = -5.46, -2.01; p < 0.001,) and 3.79 min (95% [CI] = -5.59, -1.98; p < 0.001), respectively. However, PM10 displayed a significant negative association exclusively with LPA, with one-level increase in PM10 resulting in a 3.7-minute reduction in LPA (95% [CI] = -6.81, -0.59, p < 0.05).ConclusionAir pollution demonstrates an inverse association with physical activity levels among older adults, potentially discouraging their engagement in physical activity. Different air quality indicators may exert varying impacts on physical activity. Future studies are warranted to enhance policy interventions aimed at reducing air pollution and promoting physical activity.

Insights into swordfish (Xiphias gladius) movement patterns and habitat utilization off the coast of northern Chile

This study reports on the fine-scale movements of swordfish (Xiphias gladius) tagged off of the Antofagasta region of northern Chile, where harpoon fishing operations date back more than seven millenia. The study was conducted within a highly productive swordfish foraging area where movements and habitat use remain poorly characterized. Swordfish were outfitted with both data storage and satellite-linked archival tags scheduled for short (&lt;30 days) and longer-term (&gt;100 days) data collection. All tags were deployed on basking swordfish using harpoon-based methods across two field seasons in March 2019 and April 2022 around oceanic fronts and offshore seamounts. Fine-scale depth and temperature data were recorded over 145 days from four adult swordfish (100-200 kg). Swordfish exhibited regionally unique diurnal behaviors with greater average daytime depths than those recorded at night (78.0 ± 66.5 and 12.7 ± 4.9 m, respectively). The average daytime depths were shallower than those previously documented for other Pacific regions, including Chile's offshore waters. Daytime basking was observed on 76% of the daily records (110 out of 145 days) and accounted for approximately 12% of the collective daylight hours. Findings align with previous swordfish tagging studies and suggest that depth distribution patterns vary considerably depending on regional oceanographic conditions. Movement data are compared with previous studies, and we discussed relative to regional fishing operations.

Collaborative Integration of Community Health Workers in Hospitals and Health Centers to Reduce Pediatric Asthma Disparities: A Quality Improvement Program Evaluation

To address pediatric asthma disparities on the South Side of Chicago, a community health worker (CHW) home visiting intervention was implemented collaboratively by academic institutions and community based health centers. This evaluation assessed the effectiveness of this longitudinal quality improvement CHW intervention in reducing asthma morbidity and healthcare utilization. All patients aged 2–18 who met the high-risk clinical criteria in outpatient settings or those who visited the ED due to asthma were offered the program. A within-subject study design analyzed asthma morbidity and healthcare utilization at baseline and follow-up. Multivariable mixed-effects regression models, adjusted for baseline demographic and asthma characteristics, were used to assess changes over time. Among 123 patients, the average age was 8.8 (4.4) years, and 89.3% were non-Hispanic black. Significant reductions were observed in the average daytime symptoms days (baseline 4.1 days and follow-up 1.6 days), night-time symptoms days (3.0 days and 1.2 days), and days requiring rescue medication (4.1 days and 1.6 days) in the past two weeks (all p < 0.001). The average number of emergency department visits decreased from 0.92 one year before to 0.44 one year after program participation, a 52% reduction (p < 0.001). No significant difference was found in hospital admissions. These results support the use of a collaborative approach to implement the CHW home visiting program as part of standard care for pediatric asthma patients in urban settings. This approach has the potential to reduce asthma disparities and underscores the valuable role of CHWs within the clinical care team.

Typhoon- and pollution-driven enhancement of reactive bromine in the mid-latitude marine boundary layer.

Tropospheric reactive bromine is important for atmospheric chemistry, regional air pollution, and global climate. Previous studies have reported measurements of atmospheric reactive bromine species in different environments, and proposed their main sources, e.g. sea-salt aerosol (SSA), oceanic biogenic activity, polar snow/ice, and volcanoes. Typhoons and other strong cyclonic activities (e.g. hurricanes) induce abrupt changes in different earth system processes, causing widespread destructive effects. However, the role of typhoons in regulating reactive bromine abundance and sources remains unexplored. Here, we report field observations of bromine oxide (BrO), a critical indicator of reactive bromine, on the Huaniao Island (HNI) in the East China Sea in July 2018. We observed high levels of BrO below 500m with a daytime average of 9.7±4.2 pptv and a peak value of ∼26 pptv under the influence of a typhoon. Our field measurements, supported by model simulations, suggest that the typhoon-induced drastic increase in wind speed amplifies the emission of SSA, significantly enhancing the activation of reactive bromine from SSA debromination. We also detected enhanced BrO mixing ratios under high NOx conditions (ppbv level) suggesting a potential pollution-induced mechanism of bromine release from SSA. Such elevated levels of atmospheric bromine noticeably increase ozone destruction by as much as ∼40% across the East China Sea. Considering the high frequency of cyclonic activity in the northern hemisphere, reactive bromine chemistry is expected to play a more important role than previously thought in affecting coastal air quality and atmospheric oxidation capacity. We suggest that models need to consider the hitherto overlooked typhoon- and pollution-mediated increase in reactive bromine levels when assessing the synergic effects of cyclonic activities on the earth system.

Nocturnal blood pressure dipping, blood pressure variability, and cognitive function in early and middle-aged adults.

Higher nighttime blood pressure (BP), less BP dipping, and higher BP variability have been linked with worse cognitive function in the elderly. The goal of this study is to explore whether this relationship already exists in early and middle adulthood. We further examined whether ethnic differences between African Americans and European Americans in BP parameters can explain ethnic differences in cognitive function. 24-h ambulatory BP monitoring and cognitive function were obtained from 390 participants (average age: 37.2 years with a range of 25-50; 54.9% African Americans; 63.6% females). We observed that higher nighttime BP, decreased dipping, and higher variability were significantly associated with lower scores on the Picture Sequence Memory Test. Significant negative associations between variability and overall composite scores were also observed. No significant associations between average 24-h or daytime BP and cognitive function were observed. Ethnic differences in nighttime diastolic pressures and dipping can explain 6.81% to 10.8% of the ethnicity difference in the score of the Picture Sequence Memory Test (ps<.05). This study suggests that the associations of nighttime BP, dipping, and variability with cognitive function already exist in young and middle-aged adults. Ethnic differences in nighttime BP and dipping can at least partially explain ethnic differences in cognitive function. The stronger association of these parameters with cognitive function than daytime or average BP in this age range raises the importance of using ambulatory BP monitoring for more precise detection of abnormal BP patterns in young adulthood.

Modeling urban air temperature using satellite-derived surface temperature, meteorological data, and local climate zone pattern—a case study in Szeged, Hungary

Urban air temperature is a crucial variable for many urban issues. However, the availability of urban air temperature is often limited due to the deficiency of meteorological stations, especially in urban areas with heterogeneous land cover. Many studies have developed different methods to estimate urban air temperature. However, meteorological variables and local climate zone (LCZ) have been less used in this topic. Our study developed a new method to estimate urban air temperature in canopy layer during clear sky days by integrating land surface temperature (LST) from MODIS, meteorological variables based on reanalysis data, and LCZ data in Szeged, Hungary. Random forest algorithms were used for developing the estimation model. We focused on four seasons and distinguished between daytime and nighttime situations. The cross-validation results showed that our method can effectively estimate urban air temperature, with average daytime and nighttime root mean square error (RMSE) of 0.5 ℃ (R2 = 0.99) and 0.9 ℃ (R2 = 0.95), respectively. The results based on a test dataset from 2018 to 2019 indicated that the optimal model selected by cross-validation had the best performance in summer, with time-synchronous RMSE of 2.1 ℃ (R2 = 0.6, daytime) and 2.2 ℃ (R2 = 0.86, nighttime) and seasonal mean RMSE of 1.5 ℃ (R2 = 0.34, daytime) and 1.2 ℃ (R2 = 0.74, nighttime). In addition, we found that LCZ was more important at night, while meteorological data contributed more to the model during the daytime, which revealed the temporal mechanisms of the effect of these two variables on air temperature estimation. Our study provides a novel and reliable method and tool to explore the urban thermal environment for urban researchers.

Severe photochemical pollution was found in large petrochemical complexes: A typical case study in North China

Large petrochemical complex (PC) widely exists in both developing and developed countries, and is expected to have a special photochemical pollution in local scale due to huge VOCs emissions. Here, a typical large-scale PC in North China was selected as the study case, to explore the character, formation and influence of local photochemical pollution regarding PCs based on an improved 0-D chemical model. In the study PC, VOCs-rich character was apparent with THCs level of 90.8 ± 28.0 ppb and THCs/NOx ratio of ∼26.2 mol/mol. Severe O3 pollution was found in warm months with monthly mean MDA1O3 of 67.3–96.0 ppb. Model simulations showed the heavy O3 pollution in this PC was attributed to high precursors rather than to unfavorable meteorology, and was more sensitive to NOx (with response of 1.42 g/g) than to THCs (with response of 0.12 g/g). The photochemical pollution formation potential of the emission plumes of this PC was very enormous, with production rate of 19.6 ppb h−1 for O3, 2.9 ppb h−1 for HCHO and 1.1 ppb h−1 for CH3CHO on daytime average, 1–5 greater than in normal urban areas. The higher production rates happened in morning hours, which explained the earlier peak time of observed O3 in PCs. And about 70% of photochemical pollution (represented by O3) would be transported to surroundings, leading to the significant photochemical-pollution hazard to the vicinity of PCs.

Numerical analysis and deep learning algorithm for photovoltaic-thermal systems using various nanofluids and volume fractions at Riyadh, Saudi Arabia

Conventional photovoltaic (PV) systems have elevated temperatures in the hot climate of Riyadh, resulting in reduced electrical power generation. Therefore, nanofluids are employed in photovoltaic-thermal (PV-T) systems to absorb the self-generated heat that limits efficient operation. In addition, developing deep learning models would help improve the optimization and control of the proposed system. This study's primary goal is to numerically examine a PV-T system under the influence of using various nanofluids with varying volume fractions in the hot climate of Riyadh and to develop time-series deep learning algorithms based on the findings in this examination to predict the PV-T system's potential. A mathematical model to investigate the PV-T panel performance under various volume concentrations and nanofluids is proposed. The generated data from the different nanofluids is deployed to train a deep learning model, which is convolutional neural networks integrated with two layers of long short-term memory (CNN-LSTM), in order to predict the PV-T panel temperature. According to the investigation's findings, the best PV-T coolant is CuO nanofluid at 4 % volume concentration. Utilizing the aforementioned nanofluid can deliver an enhancement in the average daytime PV-T panel temperature, electrical, thermal, and total exergy efficiency by 34.5 °C, 16.7 %, 79.2 %, and 18.07 %, respectively. The developed deep learning algorithms were evaluated using the mean absolute error (MAE) and coefficient of determination (R2) and scored 0.18–0.35 and 97.5–98.75 %, respectively.

MAVEN/IUVS Observations of OH Prompt Emission: Daytime Water Vapor in the Thermosphere of Mars

AbstractWe report the highest altitude detection of water vapor on Mars to date. The daytime limb observations by the Imaging Ultraviolet Spectrograph (IUVS) on the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft are of hydroxyl (OH) prompt emission near 308 nm, which is excited directly from the photodissociation of water vapor by the solar Lyman‐α flux. Average IUVS daytime water vapor densities near 130 km are 3 × 107 cm−3 around perihelion. The water vapor densities diurnally vary with a peak near midday and no detection at sunrise and sunset. To evaluate the large daytime water vapor densities for self‐consistency, we also report the simultaneous observation of OH solar fluorescence emission near 308 nm in the thermosphere, which enables the retrieval of OH densities. Using a one‐dimensional photochemical model initialized with the daytime IUVS water vapor densities, modeled peak OH densities are in good agreement with the observed IUVS peak OH densities. Because the observed thermospheric temperatures are controlled by solar insolation and cross the water frost point during the day, we suggest that the IUVS observed water vapor is created by the daily sublimation of water ice particles supplied from below. We discuss the implications of the IUVS observations on the present day loss of water vapor from Mars in the form of atomic hydrogen.

Experimental study on the various varieties of photovoltaic panels (PVs) cooling systems to increase their electrical efficiency.

This study investigates the impact of cooling methods on the electrical efficiency of photovoltaic panels (PVs). The efficiency of four cooling techniques is experimentally analyzed. The most effective approach is identified as water-spray cooling on the front surface of PVs, which increases efficiency by 3.9% compared to the case without cooling. The results show that water-spray cooling raises the PV's temperature to 41°C, while improving its average daytime efficiency to 22%. Air-cooling, water-cooling in the tubes behind the PV, and aluminum oxide-water nanofluid cooling in the tubes behind the PV improve efficiency by 1.1%, 1.9%, and 2.7%, respectively. The findings highlight the potential of water-spray cooling as a cost-effective and efficient method to enhance PV efficiency and contribute to the global effort towards renewable energy.

Interactive Screen-Based Activities Predict Worse Actigraphic Sleep Health That Night Among Adolescents

PurposeTo determine the micro-longitudinal effects of duration and timing of screen-based activities on sleep within and between adolescents. MethodsDaily survey and actigraphy data from the age 15 wave of the Future of Families and Child Wellbeing Study were analyzed using multilevel modeling. Four hundred seventy five adolescents provided three or more days of valid daily survey and nighttime sleep data. ResultsWithin-person results showed that on days when adolescents played video games more than their daytime average ± SE (1.3 ± 1.2 hours), sleep onset (6 ± 2 minutes, p < .01) and midpoint (4 ± 2 minutes, p < .02) were delayed for each additional hour of gaming. Between-person results showed that for each hour adolescents used screens to communicate with friends across the day, sleep onset was later (11 ± 3 minutes, p < .01), sleep midpoint was later (8 ± 3 minutes, p < .01), and sleep duration was shorter (−5 ± 2 minutes, p < .03). Adolescents who used screens to communicate with friends or play video games in the hour before bed had later sleep onset (30 ± 14 minutes, p < .03) and midpoint (25 ± 13 minutes, p < .05). DiscussionAmong adolescents, passive screen usage such as browsing the Internet or watching videos may not affect sleep timing or duration, but limiting interactive screen-based activities could protect adolescent sleep health and well-being.

Photovoltaic passive cooling via water vapor sorption-evaporation by hydrogel

Photovoltaic (PV) power generation, which converts sunlight into electricity, stands as a pivotal mode of solar energy utilization. The thermal effect poses a significant challenge for all types of PV panels under real operating conditions, as it diminishes both the photovoltaic conversion efficiency and the lifespan of the PV panels. This paper presents a novel passive cooling approach for silicon-based photovoltaic panels, employing night-time hygroscopic hydrogel adsorption, daytime desorption, and subsequent water evaporation for cooling. Both laboratory and outdoor experiments were conducted to validate this strategy. Experimental results reveal that under simulated laboratory light of 1 kW m−2, the hydrogel cooling layer delivers an average cooling power of 288.2 W m−2. It lowers the PV panel temperature by 9.9 °C and enhances both the maximum power and efficiency at equilibrium by 5.92% and 5.93%, respectively. Outdoor experiments in Beijing, China, during summer demonstrated that this method reduced the average daytime temperature of the PV plate by 7.1 °C and increased the average maximum power by 5.21%. The hydrogel layer's high hygroscopicity enables it to support passive cooling effectively all day. Passive cooling strategies for PV panels, leveraging the atmospheric water harvesting cycle, face fewer application constraints. They offer the potential to increase power generation and reduce CO2 emissions from PV plants both now and in the future.