Average Temperature Variation Research Articles

Investigation of the cooling performance and thermal comfort for 4-way cassette air conditioner with swinging motion of vanes

A numerical simulation was carried out to investigate the cooling performance and thermal comfort of a 4-way cassette air conditioner when its vanes are positioned at constant angles of 30°, 40°, 50° and 60° and swinging with a constant angular velocity. The indoor airflow characteristics and thermal comfort were evaluated. The average room temperature variation with respect to time have a good agreement with the measured data with a maximum relative error of 2 %. The average room air temperature variation according to time shows that the case of swinging vane is increased by 5.9 %, compared to the case of fixed vane angle of 60°, due to the enhancement of heat transfer by the swinging motion of discharged airflow. Moreover, the flapping discharged airflow resulting from the swinging motion makes occupants feel thermally more comfortable, based on thermal comfort indices.

COMPARATIVE CHARACTERISTICS OF CHICKPEA VARIETIES BY COMPLEX OF ECONOMIC AND VALUE TRAITS IN THE CONDITIONS OF THE RIGHT BANK FOREST STEPPE OF UKRAINE

The article summarizes the information on the current state of the economic use of chickpea varieties, which are available in the State Register of the varieties suitable for distribution in our country. The data on the dynamics of their implementation by years have been generalized with the given characteristics of the varieties according to the complex of economic-valuable peculiarities. The results of the analysis of varietal resources and yield of chickpeas according to their agroecological plasticity and grain productivity in the conditions of climate change in the zone of the right-bank Forest Steppe of Ukraine have been also scientifically substantiated. It has been determined that as of 2020, there are 21 varieties of chickpeas in the State Register of Plant Varieties Suitable for Distribution in Ukraine. The most promising varieties by maturity group, yield level have been determined. The assortment characterized by stable realization of genetic potential in various limits of variation of average daily air temperatures and conditions of moisture supply is. Therefore, the most promising varieties of chickpeas Skarb and Dostatok have been identified. On the basis of the analysis of domestic and foreign scientific literature, various technological aspects of chickpea cultivation have been studied in order to ensure the rational use of natural agricultural potential, which will further increase the sown area of these plants. The relevance of the research reveals itself in the tasks of applied research on the basis of research sites of Vinnytsia National Agrarian University («Development of methods for improving the technology of growing legumes using biofertilizers, bacterial preparations, foliar fertilizers and physiologically active substances»).

Extreme weather conditions and dengue outbreak in Guangdong, China: Spatial heterogeneity based on climate variability

BackgroundPrevious studies have shown associations between local weather factors and dengue incidence in tropical and subtropical regions. However, spatial variability in those associations remains unclear and evidence is scarce regarding the effects of weather extremes. ObjectivesWe examined spatial variability in the effects of various weather conditions on the unprecedented dengue outbreak in Guangdong province of China in 2014 and explored how city characteristics modify weather-related risk. MethodsA Bayesian spatial conditional autoregressive model was used to examine the overall and city-specific associations of dengue incidence with weather conditions including (1) average temperature, temperature variation, and average rainfall; and (2) weather extremes including numbers of days of extremely high temperature and high rainfall (both used 95th percentile as the cut-off). This model was run for cumulative dengue cases during five months from July to November (accounting for 99.8% of all dengue cases). A further analysis based on spatial variability was used to validate the modification effects by economic, demographic and environmental factors. ResultsWe found a positive association of dengue incidence with average temperature in seven cities (relative risk (RR) range: 1.032 to 1.153), a positive association with average rainfall in seven cities (RR range: 1.237 to 1.974), and a negative association with temperature variation in four cities (RR range: 0.315 to 0.593). There was an overall positive association of dengue incidence with extremely high temperature (RR:1.054, 95% credible interval (CI): 1.016 to 1.094), without evidence of variation across cities, and an overall positive association of dengue with extremely high rainfall (RR:1.505, 95% CI: 1.096 to 2.080), with seven regions having stronger associations (RR range: 1.237 to 1.418). Greater effects of weather conditions appeared to occur in cities with higher economic level, lower green space coverage and lower elevation. ConclusionsSpatially varied effects of weather conditions on dengue outbreaks necessitate area-specific dengue prevention and control measures. Extremes of temperature and rainfall have strong and positive associations with dengue outbreaks.

Overwintering Larval Cold Tolerance of Sirex noctilio (Hymenoptera: Siricidae): Geographic Variation in Northeast China

Simple SummaryThe cold tolerance strategy of Sirex noctilio overwintering larvae was freeze-avoidance and their supercooling points adjusted seasonally to avoid icing damage. The cold hardiness between different populations varied on a spatiotemporal scale; specifically, the harsher the environment, the stronger the cold tolerance of overwintering Sirex noctilio larvae. A tunnel played a certain protective role but did not affect the low temperature parameters limiting the distribution of S. noctilio. We provide experimentally determined low temperature limiting parameters of Sirex noctilio and prove it has the opportunity to spread and colonize in other regions.Sirex noctilio (Hymenoptera: Siricidae) is an invasive pest that has spread and established in many regions worldwide. However, its cold tolerance strategy is still unclear. We measured the supercooling point (SCP) and the lower lethal temperature (LLT) of overwintering S. noctilio larvae during three overwintering periods in four geographically separated populations in China. In addition, using the statistical analysis of the local historical temperature data, we also conducted comprehensive studies of S. noctilio cold tolerance variations and strategies. We measured the SCP of all samples as S. noctilio could survive at its SCP during a short period of exposure (<48 h) and its cold tolerance strategy was freeze-avoidance. The average SCPs of the groups in different spatiotemporal scales were significantly related to average temperature variation with most individuals exhibiting stronger cold hardiness at low ambient temperatures. S. noctilio exhibited a strong cold tolerance and it has the ability to withstand lower temperatures in cold environments. The geographic population showed a positive tendency as the ambient temperature decreased, which would increase its chance of developing in cold regions.

Thermo-mechanical behavior of a full-scale energy pile equipped with a spiral pipe configuration

This study investigates the thermo-mechanical behavior of energy piles equipped with a spiral pipe configuration. The analysis is based on the results of a full-scale energy pile as well as three-dimensional thermo-mechanical finite element analyses. The thermo-mechanical behavior of two energy piles with five U-shaped pipes connected in series and parallel, characterized by the same total length of the piping network, is also analyzed numerically for comparison purposes. The results of this work highlight that energy piles equipped with a spiral pipe configuration are characterized by the lowest trends of average temperature variation and thermally induced vertical stress within their volume, as compared to energy piles equipped with five U-shaped pipe configurations connected in series or parallel. Considerable variations in temperature and thermally induced vertical stress arise in the vicinity of the piping network embedded in all of the considered energy piles. Nevertheless, energy piles equipped with a spiral pipe configuration appear the best solution for practical applications in comparison with U-shaped pipe configurations of the same total length, because they maximize the heat exchange that is achieved with the ground and minimize the associated thermally induced variations of their mechanical response.

Temperature and Mental Health: A Systematic Review and Meta-Analysis

Background: The relationship between ambient temperature and mental health outcomes has not been sufficiently synthesised and communicated. Methods: A systematic search included all original studies on humans until 20/03/2020 examining a relationship between ambient temperatures and mental health outcomes (suicide, hospital attendance for mental disorders, community mental health and emotional wellbeing). Databases WebOfScience, Embase, PsychINFO, and PubMed were searched, alongside a limited search of Google Scholar. The risk of bias for individual studies was assessed using the Newcastle-Ottawa Scale (NOS), while the quality of evidence across studies was assessed using the GRADE approach. Findings: 123 studies were included in the review, with 19 studies suitable for meta-analysis. Pooled data on suicide rates (7 articles, N=1,805,734) indicate a risk ratio of 1.01 per 1oC increase in mean temperature (95%CI: 1.00, 1.01), a 1.7% increase (95%CI: 1.1%, 2.3%) in suicide incidence per 1oC temperature rise (5 articles, N=219,096), and a 6.2% (95%CI: 5.2%, 7.2%) increase for each 2-5oC temperature rise (3 articles, N=416,976). Hospital attendance for mental disorders was 9.7% higher (95%CI: 7.6%, 11.9%) during heatwaves than non-heatwave periods (3 articles, N=362,086), with a risk ratio of 1.02 (95%CI: 1.01, 1.03) at the 99th temperature percentile compared with the 50th (3 articles, N=532,296). In qualitative synthesis of the literature, higher ambient temperature (including average temperatures, heatwaves and temperature variation) across multiple time windows were positively associated with increases in attempted and completed suicides (78 studies in this category, >3,976,577 suicide events), increased hospital attendance for mental disorders (33 studies, >6,222,993 hospital attendances), and worse outcomes for community mental health and wellbeing (15 studies, >4,875,006 individuals). Interpretation: Climate change brings increasing ambient temperatures, heatwaves and temperature variation, which are all risk factors for worse mental health outcomes. Health system leaders and policy makers must be adequately prepared. Building resilience to the impacts of increasing temperatures on mental health outcomes in public health and health systems will require equitable and proactive support for those most vulnerable, including individuals with a diagnosable mental disorder, rural populations and those in 'urban heat islands'. Although many LMIC are particularly vulnerable to climate change, only 25 studies were conducted in these regions. More good quality standardised research is required to improve our understanding of the nature, severity, context and modulating factors of these effects. Funding Statement: RT receives a studentship from the National Institute for Health Research (NIHR) School for Public Health Research (PD-SPH-2015). MBT is partially supported by a donation from Marit Mohn to the Mohn Centre for Children’s Health and Wellbeing. No other external funding contributed to the study or researcher's time. Declaration of Interests: None to declare.

Weather Variability, Socioeconomic Factors, and Pneumonia in Children Under Five-Years Old - Bangladesh, 2012-2016.

What is already known on this topic?Different socioecological factors were associated with childhood pneumonia in Bangladesh. However, previous studies did not assess spatial patterns, and socioecological factors and spatial variation have the potential to improve the accuracy and predictive ability of existing models.What is added by this report?The spatial random effects were present at the district level and were heterogeneous. Average temperature, temperature variation, and population density may influence the spatial pattern of childhood pneumonia in Bangladesh.What are the implications for public health practice?The study results will help policymakers and health managers to identify the vulnerable districts, plan further investigations, help to improve proper resource allocation, and improve health interventions.

Seasonal Temperature-Salinity Variability at Khanh Hoa - Ca Mau Sea Region

Temperature-Salinity (T-S) data was analyzed from many investigations in northeast and southwest monsoon by lots of projects, which were surveyed at Khanh Hoa-Ca Mau sea region. The results showed that the variation of average temperature all domains in southwest monsoon is greater than in northeast monsoon at surface layer about 2.3°C, middle layer 1.2°C, and bottom layer 1.6°C. In addition, there are the same with variation of average salinity. Salinity in southwest monsoon is greater than in northeast monsoon at surface layer about 0.7‰, middle layer 0.3‰, and bottom layer 0.1‰. The seasonal variation of the two seasons has some common points, as temperature decrease steadily from south to north, salinity increase significant at bottom layer and maximum at 34.54‰. T-S variability in temporal and special scale is showed at three layers: T-S variability is small at the first layer (from surface to 10 m), is strong at the second layer (from 10m to 40m), and is quite stable at the third layer (from 40m to bottom).

Meteorological influences on solar energy production in a coastal Amazon region

A study was conducted with a photovoltaic distributed generation system in São Luís, Brazil, to determine the influence of meteorological variables on the generation of energy. The methodology is composed of three stages: the first corresponds to the obtaining, organization, and treatment of the data; the second involves the application of mathematical models to determine the yield, operating temperature, nominal power, and estimated power; and the third is to generate the correlations obtained between the monitored climatic variables, whether on an hourly, daily, monthly, or annual scale. For an average temperature of 27.50ºC in March, it was verified that the ultraviolet radiation was 5.06, while the average of the total radiation was 481.01 W.m-2. The maximum peak temperature was 27.88°C at noon, while the ultraviolet radiation was 8.55 and total radiation was 794.97 W.m-2. At this average temperature variation of 0.38°C, there is a variation of 313.96 W.m-2. It is concluded that, because São Luís is very close to the equator, the conditions to produce the system are favorable, mainly because, on average, there were no abrupt changes in temperature and radiation for the period studied. Even in the wintry period, the production behaved within the parameters designed.

Impacto das mudanças climáticas no ambiente térmico interno de habitação unifamiliar em Cuiabá-MT

Objetiva-se nessa pesquisa avaliar os impactos das mudanças climáticas no desempenho termoenergético de habitação de interesse social localizada na cidade de Cuiabá-MT, considerando propostas de adequação de sua envoltória tanto no Cenário Base (1961-1990) quanto nos cenários de prospecção de aquecimento global - 2020 (2011-2040), 2050 (2041-2070) e 2080 (2071-2100). As prospecções foram feitas por meio de simulação computacional, utilizando o software EnergyPlus, seguindo as etapas metodológicas: i) preparação dos arquivos climáticos futuros; ii) definição da tipologia construtiva de habitação de interesse social denominada “HISp”; iii) implementação de adequações na envoltória para enquadramento aos melhores níveis das normativas e regulamentos brasileiros de desempenho termoenergético no Cenário Base, obtendo-se a tipologia denominada “HISa”; iii) simulação computacional da temperatura e umidade do ar externo e no interior dos ambientes de permanência prolongada da habitação; e iv) análise comparativa das intervenções. Os impactos quantificados apontam para uma variação da temperatura externa e umidade relativa do ar média anual de 21,5% (+5,75°C) e 22% (-15,4%), respectivamente, até o Cenário 2080, se comparadas ao Cenário Base. As envoltórias das habitações HISa e HISp classificaram-se como “A” e “D” no Cenário Base e ambas como “E” no Cenário 2080. O consumo relativo de energia para condicionamento térmico artificial provisionado para HISp e da HISa poderá se elevar em 83,75% e 99,63%, respectivamente, em 2080, se comparado ao Cenário Base. Prevalecendo as condições climáticas provisionadas, estas poderão ser impeditivas à manutenção da classificação da eficiência energética da envoltória como “A”, desencadeando elevado consumo de energia para resfriamento.

Os climas do Rio Grande do Sul: uma proposta de classificação climática

Este trabalho apresenta a classificação climática elaborada para o estado do Rio Grande do Sul, resultado da tese “Os climas do Rio Grande do Sul: variabilidade, tendências e tipologia”. O método de classificação climática contemplou análises qualitativas e quantitativas, baseadas na climatologia genética e dinâmica, em associação com análises estatísticas. Com relação à tipologia climática, o estado do Rio Grande do Sul se situa em área de domínio do Clima subtropical, subdividido em quatro tipos principais: Subtropical I - Pouco Úmido (dividido em Subtropical Ia - Pouco úmido com inverno frio e verão fresco e Subtropical Ib - Pouco úmido com inverno frio e verão quente); Subtropical II - Medianamente úmido com variação longitudinal das temperaturas médias; Subtropical III - Úmido com variação longitudinal das temperaturas médias; e d) Subtropical IV - Muito úmido (dividido em Subtropical IVa - Muito úmido com inverno fresco e verão quente e Subtropical IVb - Muito úmido com inverno frio e verão fresco). O Rio Grande do Sul apresenta regiões climaticamente bem diferenciadas, evidenciando certa heterogeneidade, ao contrário de grande parte das classificações climáticas mais conhecidas do estado.

Influence of Urban Scale and Urban Expansion on the Urban Heat Island Effect in Metropolitan Areas: Case Study of Beijing–Tianjin–Hebei Urban Agglomeration

Global large-scale urbanization has a deep impact on climate change and has brought great challenges to sustainable development, especially in urban agglomerations. At present, there is still a lack of research on the quantitative assessment of the relationship between urban scale and urban expansion and the degree of the urban heat island (UHI) effect, as well as a discussion on mitigation and adaptation of the UHI effect from the perspective of planning. This paper analyzes the regional urbanization process, average surface temperature variation characteristics, surface urban heat island (SUHI), which reflects the intensity of UHI, and the relationship between urban expansion, urban scale, and the UHI in the Beijing–Tianjin–Hebei (BTH) urban agglomeration using multi-source analysis of data from 2000, 2005, 2010, and 2015. The results show that the UHI effect in the study area was significant. The average surface temperature of central areas was the highest, and decreased from central areas to suburbs in the order of central areas &gt; expanding areas &gt; rural residential areas. From the perspective of spatial distribution, in Beijing, the southern part of the study area, the junction of Tianjin, Langfang, and Cangzhou are areas with intense SUHI. The scale and pace of expansion of urban land in Beijing were more than in other cities, the influencing range of SUHI in Beijing increased obviously, and the SUHI of central areas was most intense. The results indicate that due to the larger urban scale of the BTH urban agglomeration, it will face a greater UHI effect. The UHI effect was also more significant in areas of dense distribution in cities within the urban agglomeration. Based on results and existing research, planning suggestions are proposed for central areas with regard to expanding urban areas and suburbs to alleviate the urban heat island effect and improve the resilience of cities to climate change.

Study of ammonia adsorption/desorption characteristics of CaCl2 – Expanded natural graphite composite for thermal energy storage

In this work, the composite adsorbent bed of CaCl2 + Expanded Natural Graphite (80:20) is tested for heat and mass transfer behavior of ammonia adsorption/desorption for thermal energy storage application. 500 g of CaCl2 + ENG was used in the reactor and the variations of average temperature in the reactor and mass of ammonia adsorbed/desorbed with time are studied at different operating conditions. Adsorption rates were measured at ammonia supply pressure of 10 and 12 bar and adsorption temperatures of 80, 85 and 90°C. Adsorption at these operating conditions was then followed by desorption rate measurement at 75°C and 80°C, where desorption takes place at ambient pressure. It was observed that adsorption is fastest when it was done at 80°C and supply pressure of 12 bar and desorption was fastest when it was done at 80°C with preceding adsorption at 80°C at 12 bar. Average temperature of adsorbent dropped down to about 52°C under these operating conditions. Based on amount of ammonia adsorbed/desorbed by CaCl2 + ENG, values of theoretical maximum energy storage density and the amount of heat that can be recovered at different adsorption temperatures and supply pressures were evaluated.

Experimental investigation on the energy storage/discharge performance of xylitol in a compact spiral coil heat exchanger

The main challenge ahead of widespread application of renewable energy sources is their availability intermittence preventing continuous power supply. In order to circumvent the temporal mismatch between their supply and demand, thermal energy storage systems can be utilized. In this study, a compact spiral coil thermal storage unit was investigated to analyze the impact of operating parameters such as inlet temperature and flow rate of the heat transfer fluid and explain the physics of heat transfer during the phase change process of xylitol. A concentric double spiral coil was inserted into a storage unit to ensure an improved heat transfer performance. Using experimental data, average temperature variation, heat storage/discharge rate and liquid fraction of xylitol in the storage unit were calculated. It was found that when the PCM melted, the lower density liquid PCM created buoyancy forces resulting in natural convection. On the other hand, discharging process was mainly governed by conduction. In the present storage unit, xylitol stored 450 kJ of heat in 35 min for an inlet temperature and flow rate of 130 °C and 2.5 lpm during charging and discharged 345 kJ in 50 min at an inlet temperature and flow rate of 45 °C and 2.5 lpm. The outcomes of this analysis are expected to be greatly applicable for the design of phase change material based spiral coil units to be used for instance in solar heating systems.

Nonlinear Optimization of Turbine Conjugate Heat Transfer with Iterative Machine Learning and Training Sample Replacement

A simple yet effective optimization technique is developed to solve nonlinear conjugate heat transfer. The proposed Nonlinear Optimization with Replacement Strategy (NORS) is a mutation of several existing optimization processes. With the improvements of 3D metal printing of turbine components, it is feasible to have film holes with unconventional diameters, as these holes are created while printing the component. This paper seeks to optimize each film hole diameter at the leading edge of a turbine vane to satisfy several optimum thermal design objectives with given design constraints. The design technique developed uses linear regression-based machine learning model and further optimizes with strategic improvement of the training dataset. Optimization needs cost and benefit criteria are used to base its decision of success, and cost is minimized with maximum benefit within given constraints. This study minimizes the coolant flow (cost) while satisfying the constraints on average metal temperature and metal temperature variations (benefits) that limit the useful life of turbine components. The proposed NORS methodology provides a scientific basis for selecting design parameters in a nonlinear design space. This model is also a potential academic tool to be used in thesis works without demanding extensive computing resources.

Delayed warming in Northeast China: Insights from an annual temperature reconstruction based on tree-ring δ18O

Global warming has had an unprecedented impact on environmental changes and thus human life in mid-high latitude regions. As one of the areas most affected by global warming, Northeast China has suffered from a series of ecological crises, including warming-induced water deficits, permafrost thaw, and extended growing seasons. The change in annual average temperature (annual T) variations in Northeast China since the Industrial Revolution are still not fully understood, mainly because of the lack of long-term instrumental data and high-resolution annual T reconstructions. Here, we present the first annual T reconstruction (r = −0.683, p < .001, n = 60) for 1818–2012 in Northeast China, which may also be the first temperature reconstruction based on tree-ring δ18O in China. The reconstruction is significantly related to temperature variations over mid-high latitude Eurasia and agree (p < .01) with several long-term hydroclimatic reconstructions in the surrounding area. When the internal variability in the reconstruction was high, the decadal to multidecadal cycles were significant. Further analysis found that the reconstruction was mainly affected by the East Asian Summer Monsoon (EASM) and North Atlantic Oscillation (NAO). The reconstruction was significantly negatively correlated with several time series of annual T in the Northern Hemisphere, which showed that there is a substantial difference in annual T between Northeast China and other regions of the Northern Hemisphere. The difference mainly existed before the 1950s. From the 1850s to the 1950s, the annual T in Northeast China decreased slightly. However, extreme warming began in the 1950s in Northeast China, and this warming has been unprecedented during the past two centuries. If the warming trend since the 1950s continues, then it will lead to devastating disasters to forest and permafrost ecosystems in Northeast China.

Association of weather factors with the risk of pain exacerbations in people with hip osteoarthritis

Objectives: Our objective was to evaluate the association of weather factors with the risk of pain exacerbations in people with symptomatic hip osteoarthritis (OA). Method: Eligible participants with symptomatic hip OA were instructed to log on to the study website and complete questionnaires every 10 days and additionally whenever they considered they were experiencing a pain exacerbation (case period) during the 90 day follow-up. Pain exacerbation was defined as an increase of two points in pain intensity on an 11-point numeric rating scale (0–10) during the follow-up compared with baseline. Each case period was anchored to four control periods within a 35 day interval using a time-stratified approach. Weather data were obtained for both periods from the publicly available meteorological database of the Australian Bureau of Meteorology. We examined the association of weather factors across 72 h before the index date with the risk of pain exacerbation, using conditional logistic regression. Results: Among 252 participants recruited, 129 participants had at least one episode of pain exacerbation and were included in the analysis. A significant dose–response relationship was found between average daily temperature variation in the prior 72 h and risk of pain exacerbations (p = 0.04 for linear trend). There was no significant association between maximum daily temperature, minimum daily temperature, relative humidity, precipitation, or barometric pressure and hip pain exacerbations. Conclusion: The overall results suggest that only daily temperature variation among different weather factors was associated with hip pain exacerbations in people with symptomatic hip OA.

Atomic-level understanding of crystallization in the selective laser melting of Fe50Ni50 amorphous alloy

Selective laser melting (SLM), an emerging technology, has enabled the fabrication of large Fe-based amorphous alloys (FAAs) with complex geometry, unlocking the potential for the wider implementation. However, the almost unavoidable crystallization during SLM greatly degrades the performance of SLM fabricated FAAs. This study aims to understand the crystallization mechanism by investigating the atomic crystallization and cluster evolution in Fe50Ni50 FAA using molecular dynamics simulation under various laser powers and scanning speeds. It is observed that crystallization occurs easily at low scanning speed due to the increased fractions of body-centered cubic (BCC) bond pairs 1661 and 1441, with corresponding Voronoi polyhedrons <0,6,0,8> and <0,5,2,6>. The ease of crystallization is interpreted by increasing laser energy density, determined by elevating laser power and lowering scanning speed. Additionally, the suppression of crystallization is explained by the increasing average temperature variation rate, while effectively shortening the relaxation time for atomic rearrangement, inhibiting the increase of BCC crystal phases. This research is conducive to comprehend relevant atomic-level information on crystallization mechanism and microstructure evolution and provides an alternative way to inhibit crystallization during the manufacture FAAs with SLM.

Impact of climate variability on length of stay in hospital for childhood pneumonia in rural Bangladesh

ObjectivesPneumonia is a significant contributor to mortality and morbidity in children aged <5 years, and it is also one of the leading causes of hospitalisation for children in this age group. This study assessed the association between climate variability, patient characteristics (i.e. age, sex, weight, parental education, socio-economic status) and length of stay (LOS) in hospital for childhood pneumonia and its economic impact on rural Bangladesh. Study designAn ecological study design was used. MethodsData on daily hospitalisation for pneumonia in children aged <5 years (including patient characteristics) and daily climate data (temperature and relative humidity) between 1st January 2012 and 31st December 2016 were obtained from the Matlab Hospital (the International Centre for Diarrhoeal Disease Research, Bangladesh) and the Bangladesh Meteorological Department, respectively. A generalised linear model with Poisson link was used to quantify the association between climate factors, patient characteristics and LOS in hospital. ResultsThe study showed that average temperature, temperature variation and humidity variation were positively associated with the LOS in hospital for pneumonia. A 1°C rise in average temperature and temperature variation during hospital stay increased the LOS in hospital by 1% (relative risk [RR]: 1.010, 95% confidence interval [CI]: 1.001–1.018) and 9.3% (RR: 1.093, 95% CI: 1.051–1.138), respectively. A 1% increase in humidity variation increased the LOS in hospital for pneumonia by 2.2% (RR: 1.022, 95% CI: 1.004–1.039). In terms of economic impact, for every 1° C temperature variation during the period of hospital stay, there is an addition of 0.81 USD/day/patient as a result of direct costs and 1.8 USD/day/patient for total costs. Annually, this results in an additional 443 USD for direct and 985 USD for total costs. ConclusionsClimate variation appears to significantly contribute to the LOS in hospital for childhood pneumonia. These findings may help policymakers to develop effective disease management and prevention strategies.

Temperature significantly changes COVID-19 transmission in (sub)tropical cities of Brazil

The coronavirus disease 2019 (COVID-19) outbreak has become a severe public health issue. The novelty of the virus prompts a search for understanding of how ecological factors affect the transmission and survival of the virus. Several studies have robustly identified a relationship between temperature and the number of cases. However, there is no specific study for a tropical climate such as Brazil. This work aims to determine the relationship of temperature to COVID-19 infection for the state capital cities of Brazil.Cumulative data with the daily number of confirmed cases was collected from February 27 to April 1, 2020, for all 27 state capital cities of Brazil affected by COVID-19. A generalized additive model (GAM) was applied to explore the linear and nonlinear relationship between annual average temperature compensation and confirmed cases. Also, a polynomial linear regression model was proposed to represent the behavior of the growth curve of COVID-19 in the capital cities of Brazil.The GAM dose-response curve suggested a negative linear relationship between temperatures and daily cumulative confirmed cases of COVID-19 in the range from 16.8 °C to 27.4 °C. Each 1 °C rise of temperature was associated with a −4.8951% (t = −2.29, p = 0.0226) decrease in the number of daily cumulative confirmed cases of COVID-19. A sensitivity analysis assessed the robustness of the results of the model. The predicted R-squared of the polynomial linear regression model was 0.81053.In this study, which features the tropical temperatures of Brazil, the variation in annual average temperatures ranged from 16.8 °C to 27.4 °C. Results indicated that temperatures had a negative linear relationship with the number of confirmed cases. The curve flattened at a threshold of 25.8 °C. There is no evidence supporting that the curve declined for temperatures above 25.8 °C. The study had the goal of supporting governance for healthcare policymakers.