Effects Of Temperature Variability Research Articles

The Effect of Temperature Variability on Biological Responses of Ectothermic Animals-A Meta-Analysis.

Climate change is altering temperature means and variation, and both need to be considered in predictions underpinning conservation. However, there is no consensus in the literature regarding the effects of temperature fluctuations on biological functions. Fluctuations may affect biological responses because of inequalities from non-linear responses, endocrine regulation or exposure to damaging temperatures. Here we establish the current state of knowledge of how temperature fluctuations impact biological responses within individuals and populations compared to constant temperatures with the same mean. We conducted a meta-analysis of 143 studies on ectothermic animals (1492 effect sizes, 118 species). In this study, 89% of effect sizes were derived from diel cycles, but there were no significant differences between diel cycles and shorter (<8 h) or longer (>48 h) cycles in their effect on biological responses. We show that temperature fluctuations have little effect overall on trait mean and variance. Nonetheless, temperature fluctuations can be stressful: fluctuations increased 'gene expression' in aquatic animals, which was driven mainly by increased hsp70. Fluctuating temperatures also decreased longevity, and increased amplitudes had negative effects on population responses in aquatic organisms. We conclude that mean temperatures and extreme events such as heat waves are important to consider, but regular (particularly diel) temperature fluctuations are less so.

Climatic variations and Fasciola: a review of impacts across the parasite life cycle.

Fasciolosis, caused by the liver fluke Fasciola spp., is a significant parasitic disease of livestock and humans worldwide. Fasciola transmission and life cycle are highly dependent on climatic conditions, especially temperature and humidity. This dependency has gained significance in the context of ongoing climate change. This literature review examined evidence on the effects of temperature variability on the developmental stages of Fasciola spp. and the snail intermediate hosts. We reviewed free larval stages of Fasciola spp. development, as well as snail intermediate hosts, while investigating the climate-related factors influencing each stage. We found that Fasciola spp. egg hatching and development were inhibited below 10 °C and optimal between 20 and 30 °C, miracidia hatching time decreased with higher temperatures and cercarial shedding by snail hosts accelerated around 27 °C. Further, metacercarial viability declined at higher temperatures but was prolonged by higher humidity. Snail intermediate host growth rates peaked at 25 °C, and their susceptibility to Fasciola infection depends on temperature, underscoring its importance in transmission dynamics. Overall, the Fasciola life cycle and snail host development exhibit stage-specific temperature thresholds, indicating a complex relationship between temperature fluctuations and parasite transmission potential. This research highlights the key role of temperature and humidity on Fasciola spp. and snail development, shedding light on the potential consequences of climate change on their survival, development, and disease transmission. Data limitations, primarily from the scarcity of high-resolution climate-related experiments, should drive future research to enhance predictive models and deepen our understanding of the impact of climate change on this parasitic disease.

Evaluating the Effects of Reducing Voltage Margins for Energy-Efficient Operation of MPSoCs

Voltage margins, or guardbands, are imposed on DVFS systems to account for process, voltage, and temperature variability effects. While necessary to assure correctness, guardbands reduce energy efficiency, a crucial requirement for embedded systems. The literature shows that error detection techniques can be used to maintain the system’s reliability while reducing or eliminating the guardbands. This letter assesses the practically available margins of a commercial RISC-V MPSoC while violating its guardband limits. The primary motivation of this work is to support the development of an efficient system leveraging the redundancy of multicore architectures for an error detection and correction scheme capable of mitigating the errors caused by aggressive voltage margin reduction. For an equivalent performance, we achieved up to 27% energy reduction while violating the manufacturer’s defined guardband, leaving reasonable energy margins for further development.

Temperature, storage, and natural gas futures prices

AbstractPrevious literature suggests that daily changes in US natural gas (NG) futures prices and their variance can be explained by changes in oil futures prices and volatilities, storage announcements, and temperature shocks. These studies measure temperature shocks using the National Oceanic and Atmospheric Administration definitions of heating degree day (HDD) and cooling degree day (CDD). We show how hourly temperatures can be used to better measure how long as well as how much temperatures depart above and/or below the “comfort level” within a day, the effects of temperature variability within a day, and the effects of thermal inertia. Hourly temperatures also allow us to construct measures of extreme temperatures that better match the timing of release of other market information. Another innovation is that we use more economically relevant weights to convert regional temperature shocks to national averages, and measure expected values of variables via econometric models instead of historical averages. Our results show that the proposed measures of HDD and CDD and temperature changes are important for explaining weekly changes in NG in storage and daily changes in NG futures prices and their variance.

Temperature variability and birthweight: Epidemiological evidence from Africa

BackgroundMounting evidence supports an association between nonoptimal ambient temperatures (i.e., heat or cold) and risk of low birthweight (LBW) (<2500 g), while the effect of temperature variability (TV) is largely unknown. We aimed to quantify the association between TV and risk of LBW in Africa. MethodsData on birthweight in 37 countries during 1990–2020 were collected from the Demographic and Health Surveys program. We calculated overall, intraday, and interday TV during the entire pregnancy and each trimester using hourly temperatures at ∼ 9 km resolution from ERA5-Land. We employed generalized linear mixed logistic regression, with random effects for country and survey cluster, to quantify the association between LBW and three separate TV metrics. ResultsIn total there were 33,863 (10.2%) LBW births out of 333,618 records. We found a J-shaped association between TV and LBW. Compared to the reference TV where the lowest risk was observed, extremely high (97.5th percentile) overall, intraday, and interday TV during the entire pregnancy increased the odds of LBW birth by 37.3% (26.7–48.8%), 24.1% (16.4–32.3%), and 15.1% (6.9–24.0%), respectively. In total, 7.3% of all LBW births in Africa were attributable to elevated overall TV. These associations were observed in dry climate zones, but not in tropical or temperate zones. ConclusionsOur study suggests an adverse impact of TV on the risk of LBW in Africa, according to three different TV definitions, underlining the significance of climate-health risk assessment in those most vulnerable to climate change.

The effects of temperature variability on mortality in patients with chronic obstructive pulmonary disease: a time-series analysis in Hangzhou, China.

Chronic obstructive pulmonary disease (COPD) is a leading cause of death in people aged over 60years old. Research has been reported that ambient temperature and diurnal temperature range (DTR), as representative indices of temperature variability, are contributors to the development and exacerbation of COPD. However, few studies are available in Chinese population. In this study, we aimed to assess the associations of temperature variability on COPD mortality in a fast developing city in China. Using the mortality surveillance system, we obtained a total of 7,863 deaths attributed to COPD from 2014 to 2016. Quasi-Poisson generalized linear regression with distributed lag non-linear model was applied to explore the associations between temperature variability and COPD deaths, after controlling for the potential confounders, including relative humidity, day of week, public holiday, and long-term trend. A J-shaped association of DTR and a reversely J-shaped association of temperature for COPD mortality were observed. Risk estimates showed that the relative risks (RRs) of COPD mortality with extreme high DTR at lag 0 and 0-7days were 1.045 (95% CI: 0.949-1.151) and 1.460 (95% CI: 1.118-1.908), and the extreme high temperature at lag 0 and 0-7days were 1.090 (95% CI: 0.945-1.256) and 1.352 (95% CI: 1.163-1.572). Our findings suggest that short-term exposure to extreme temperature was associated with mortality for COPD in Hangzhou. The evidence has implications for policy decision-making and targeted interventions.

Simulation model for the dynamics of dengue with asymptomatic transmission and the effect of temperature

Background: One of the fastest spreading vector-borne diseases in tropical and subtropical regions is dengue, which generates cost overruns for public health entities. Several factors can influence the dynamics of dengue virus transmission: environmental and climatic (abundance of vectors), interactions between hosts (infections by asymptomatic individuals), and population immunological factors. Given these conditions, it is necessary to carry out theoretical studies based on meteorological factors and asymptomatic transmission that are associated with both the existence of the vector and its incidence, in order to provide a scientific basis for health entities in decision-making. Methods: A mathematical model based on nonlinear ordinary differential equations is proposed to interpret the dynamics of dengue transmission in humans coupled to the dynamics of the Aedes aegypti species, considering the population of symptomatic and asymptomatic infected humans and the effect of temperature variability. The basic reproduction number was found and some simulation results based on the Runge-Kutta numerical method were obtained. Results: The simulations showed that the temperature had a directly proportional relationship with the basic reproduction number. The cases of infected people and carrier mosquitoes increased when the temperature peaks increased drastically; in low temperatures the infection persisted with low morbidity due to the survival of asymptomatic people. Conclusions: High temperatures tolerable by mosquitoes increase their life expectancy and their numbers in the environment which, together with a reservoir of asymptomatic infected people, leads to a higher incidence of the dengue virus in certain seasons or maintains its circulation in seasons of low temperatures, despite lower vector survival rates.

Relationship between temperature and Anopheles gambiae sensu lato mosquitoes' susceptibility to pyrethroids and expression of metabolic enzymes

BackgroundMalaria remains one of the most devastating diseases globally, and the control of mosquitoes as the vector is mainly dependent on chemical insecticides. Elevated temperatures associated with future warmer climates could affect mosquitoes' metabolic enzyme expression and increase insecticide resistance, making vector control difficult. Understanding how mosquito rearing temperatures influence their susceptibility to insecticide and expression of metabolic enzymes could aid in the development of novel tools and strategies to control mosquitoes in a future warmer climate. This study evaluated the effects of temperature on the susceptibility of Anopheles gambiae sensu lato (s.l.) mosquitoes to pyrethroids and their expression of metabolic enzymes.MethodsAnopheles gambiae s.l. eggs obtained from laboratory-established colonies were reared under eight temperature regimes (25, 28, 30, 32, 34, 36, 38, and 40 °C). Upon adult emergence, 3- to 5-day-old female non-blood-fed mosquitoes were used for susceptibility tests following the World Health Organization (WHO) bioassay protocol. Batches of 20–25 mosquitoes from each temperature regime (25–34 °C) were exposed to two pyrethroid insecticides (0.75% permethrin and 0.05% deltamethrin). In addition, the levels of four metabolic enzymes (α-esterase, β-esterase, glutathione S-transferase [GST], and mixed-function oxidase [MFO]) were examined in mosquitoes that were not exposed and those that were exposed to pyrethroids.ResultsMortality in An. gambiae s.l. mosquitoes exposed to deltamethrin and permethrin decreased at temperatures above 28 °C. In addition, mosquitoes reared at higher temperatures were more resistant and had more elevated enzyme levels than those raised at low temperatures. Overall, mosquitoes that survived after being exposed to pyrethroids had higher levels of metabolic enzymes than those that were not exposed to pyrethroids.ConclusionsThis study provides evidence that elevated temperatures decreased An. gambiae s.l. mosquitoes' susceptibility to pyrethroids and increased the expression of metabolic enzymes. This evidence suggests that elevated temperatures projected in a future warmer climate could increase mosquitoes' resistance to insecticides and complicate malaria vector control measures. This study therefore provides vital information, and suggests useful areas of future research, on the effects of temperature variability on mosquitoes that could guide vector control measures in a future warmer climate.Graphical

Modified effects of air pollutants on the relationship between temperature variability and hand, foot, and mouth disease in Zibo City, China.

Hand, foot, and mouth disease (HFMD) poses a great disease burden in China. However, there are few studies on the relationship between temperature variability (TV) and HFMD. Moreover, whether air pollutions have modified effects on this relationship is still unknown. Therefore, this study aims to explore the modified effects of air pollutants on TV-HFMD association in Zibo City, China. Daily data of HFMD cases, meteorological factors, and air pollutants from 2015 to 2019 were collected for Zibo City. TV was estimated by calculating standard deviation of minimum and maximum temperatures over the exposure days. We used generalized additive model to estimate the association between TV and HFMD. The modified effects of air pollutants were assessed by comparing the estimated TV-HFMD associations between different air stratums. We found that TV increased the risk of HFMD. The effect was strongest at TV03 (4days of exposure), when the incidence of HFMD increased by 3.6% [95% CI: 1.3-5.9%] for every 1℃ increases in TV. Males, children aged 0-4years, were more sensitive to TV. We found that sulfur dioxide (SO2) enhanced TV's effects on all considered exposure days, while ozone (O3) reduced TV's effects on some exposure days in whole concerned population. However, we did not detect significant effect modification by particulate matter less than 10 microns in aerodynamic diameter (PM10). These findings are of significance in developing policies and public health practices to reduce the risks of HFMD by integrating changes in temperatures and air pollutants.

Effects of Temperature Variability on Global, Regional, and National Incidence Rates of Meningitis

Effects of Temperature Variability on Global, Regional, and National Incidence Rates of Meningitis

Hourly temperature variability and mortality in 31 major Chinese cities: Effect modification by individual characteristics, season and temperature zone

In the context of ongoing climate change, temperature variability (TV) has been considered as an important trigger of death. However, evidence of association between mortality and hourly temperature variability (HTV) is scarce at the multi-city level, and the time window of health effects of HTV is lack of investigation. This study aims at quantifying the mortality risk and burden of HTV and exploring subpopulations susceptible to HTV from a large-scale multi-city perspective. Data on daily number of deaths and meteorology were collected for 31 Chinese major cities during 2007-2013. HTV was calculated as the standard deviation of hourly temperature within a few days. The optimal exposure period of HTV was chosen according to multiple scientific criteria. A quasi-Poisson regression combined with distributed lag nonlinear model was used to assess the city-specific HTV-mortality associations. Then, meta-analysis was further applied to pool city-specific effect estimates. Finally, we calculated the fraction of mortality attributable to HTV. Stratification analyses were conducted by individual characteristics (i.e. age, sex, and educational attainment), season, and region. HTV calculated in a relatively long-time window like 18 d (HTV0-17) could capture the impact of HTV adequately. Per 1°C raise of HTV0-17 associated with 1.38% (95%CI: 0.77, 1.99) increase of non-accidental mortality. During the study period, 5.47% (95%CI: 1.06, 9.64) of non-accidental mortality could be attributed to HTV. The females, the elderly, and individuals with low education level were more susceptible to HTV than their counterparts, respectively. Moreover, a stronger HTV-mortality association was observed in individuals who live in warmer season and temperature zone. HTV is associated with a considerable mortality burden, which may be modified by season, geographic and individual-level factors. Our findings highlight the practical importance of establishing early warning systems and promoting health education to mitigate the impacts of temperature variability.

Mixed finite element formulation for the nonlinear analysis of buckling behavior of truss under effects of temperature variation

This paper proposes a novel approach to consider the effects of temperature variability in the nonlinear finite element analysis of buckling behavior of truss system subjected to initial mechanical load. Generally, using displacement-based finite formulation the procedure for solving geometrically nonlinear problem of the truss system subjected to temperature load is required to implement the temperature deformation constraint depending on the incremental element length to the master stiffness equation. For escaping the mathematical difficulties of treating the additional constraint of temperature deformation this research proposes to formulate this problem based on mixed finite element formulation. The balanced mixed equation of truss considering temperature loading effect is constructed based on the principle virtual work with establishing the mixed matrix of truss element, which consists the element temperature deformation, considering large displacement. For investigating the effects of temperature variation to the nonlinear buckling behavior of truss this research develops the incremental-iterative algorithm for solving the nonlinear equation with incremental displacement and temperature by using Newton-Raphson technique. Based on proposed algorithm the calculation program is written for numerical investing the effects of temperature variation the buckling behavior of plan truss.

Effects of temperature variability and extremes on spring phenology across the\xa0contiguous United States from 1982 to 2016

Warming climate and its impact on vegetation phenological trends have been widely investigated. However, interannual variability in temperature is considerably large in recent decades, which is expected to trigger an increasing trend of variation in vegetation phenology. To explore the interannual phenological variation across the contiguous United States (CONUS), we first detected the onset of vegetation greenup using the time series of the daily two-band Enhanced Vegetation Index (EVI2) observed from the AVHRR Long-Term Data Record (1982–1999) and the MODIS Climate Modeling Grid (2000–2016). We then calculated the interannual variation in greenup onset during four decadal periods: 1982–1989, 1990–1999, 2000–2009 and 2010–2016. Further, the trend of interannual variation in greenup onset from 1982 to 2016 was analyzed at pixel and state levels. Extreme phenological events were also determined using a greenup onset anomaly for each pixel. Similar approaches were applied to spring temperatures to detect extreme years and to the temporal trend of interannual variation to explain the phenological variation. The results revealed that 62% of pixels show an increasing interannual variation in greenup onset, and in 44% of pixels, this variation could be explained by the temperature. Although extreme phenology occurred locally in different years, three nationwide extreme phenological years were distinguished. The extreme warm spring that occurred in 2012 resulted in the occurrence of greenup onset as much as 20 days earlier than normal in large parts of the CONUS. In contrast, greenup onset was much later (up to 30 days) in 1983 and 1996 due to cool spring temperatures. These findings suggest that interannual variation in spring phenology could be much stronger in the future in response to climate variation, which could have more significant impacts on terrestrial ecosystems than the regular long-term phenological trend.

Temperature Variability Does Not Attenuate the Beneficial Effects of Therapeutic Hypothermia on Cellular Apoptosis and Endoplasmic Reticulum Stress in the Cerebral Cortex of a Swine Cardiac Arrest Model.

Endoplasmic reticulum stress (ERS) plays a vital role in mediating apoptosis in the brain following cardiac arrest (CA). Studies have shown that therapeutic hypothermia (TH) provides neuroprotection through anti-apoptosis; however, the effects of temperature variability in TH on the brain remain unclear. In this study, we investigated the different effects of temperature variability through extracorporeal membrane oxygenation on apoptosis and ERS in the brain following CA. Eighteen male domestic pigs underwent 6-min duration of no-flow induced by ventricular fibrillation. Extracorporeal cardiopulmonary resuscitation was then performed, and the return of spontaneous circulation (ROSC) was achieved. The animals were randomly assigned to the following groups: normothermia, non-temperature variability, and temperature variability. TH (core temperature, 33-35°C) was maintained for 24h post-ROSC, and the animals were rewarmed for 8h. Quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry for Bax and Bcl-2 transcripts and proteins, respectively, were used to investigate apoptosis in the cerebral cortex. Expression levels of the ERS molecules, GRP78 and CHOP, were also detected by qRT-PCR, and cellular morphology was evaluated using transmission electron microscopy. qRT-PCR and immunohistochemistry results revealed that TH significantly increased the expression levels of Bcl-2 and GRP78 and decreased that of Bax and CHOP than under normothermia conditions. Compared to the non-temperature variability group, temperature variability did not decrease the expression levels of Bcl-2 and GRP78 and not increase the levels of Bax and CHOP. Endoplasmic reticulum ultrastructural changes were significantly improved under TH. No statistical difference was observed between the temperature variability andnon-temperature variabilitygroups. TH can reduce neuronal apoptosis by ERS, while temperature variability does not attenuate this beneficial effect.

Effects of Temperature Variability and Warming on the Timing of Snowmelt Events in Southern Finland during the Past 100 Years

This study analyses the first and last days of snowmelt events and the number of days (duration) between those throughout a water year (September-August). The snowmelt duration (SD) as well as its first (SFD) and last (SLD) days were estimated using daily precipitation and temperature measurements at the Kaisaniemi meteorological station in southern Finland during 1909-2008 as input datasets to a temperature-index snowmelt model. As snowmelt is a sensitive hydrological variable to temperature, this study also evaluated historical variations and trends in November-May (SDt), November-January (SFDt), and March-May (SLDt) temperatures corresponding to SD, SFD, and SLD at Kaisaniemi. The trends in all these parameters as well as their correlations with the well-known climate teleconnections over Finland were investigated. Long-term average values indicated the longest SD was about 131 days between 15 December and 25 April at Kaisaniemi. The SD significantly (p&lt;0.05) shortened by 0.37 (days/year) at Kaisaniemi during 1909-2008 mainly due to the earlier (0.32 days/year) SLD. Such trends in SD and SLD were principally associated with century-long significant warming trends (0.02 °C/year) in both SDt and SLDt. The Arctic Oscillation (AO) was the most influential climate teleconnection for historical variations in SD, SLD, SDt, SFDt, and SLDt at Kaisaniemi.

Anaerobic codigestion of bovine manure and banana tree leaf: the effect of temperature variability on biogas yield in different proportions of waste

Anaerobic codigestion of bovine manure and banana tree leaf: the effect of temperature variability on biogas yield in different proportions of waste

Pengaruh Suhu Reaksi Pada Proses Hidrasi Alpha Pinene Dengan Katalisator Amberlyst 36

Indonesian turpentine contains 65-85% α-pinene, 1% camphene, 1-3% β-pinene, 10-18% 3-carene and 1-3% limonene. The largest content of turpentine is alpha pinene. Alpha pinene is also a monoterpene compound that has double bonds and is the main raw material in the perfume industry. In addition, alpha pinene is also an important raw material for the manufacture of fine chemicals that have high sales value such as pine oil, camphor and alpha terpineol. To increase the sale value, alpha pinene can be further processed into derivative compounds such as alpha terpineol and alpha terpinyl acetate. Both are valuable derivative compounds used in the perfume industry and the pharmaceutical industry. Hydration is the reaction between alpha pinene and water to produce alpha terpineol compounds. In the reaction process that will be carried out on alpha pinene usually uses a catalyst that can accelerate the reaction rate without becoming a byproduct, catalyst used in this study is a type of resin. This study aims to study the effect of temperature variables at temperatures of 65, 75, 85 and 95⁰C. The conversion of alpha pinene increase with increasing reaction temperature. Assuming a reversible reaction, the relationship of temperature to each reaction rate constant is determined according to the Arrhenius equation.

Spatiotemporal and demographic variation in the association between temperature variability and hospitalizations in Brazil during 2000–2015: A nationwide time-series study

BackgroundExtreme temperature events are known to be adversely associated with a range of health outcomes, but little is known about the effect of less extreme, but more frequent fluctuation in temperature. We examined the spatiotemporal and demographic variation in the effect of temperature variability (TV) on nationwide hospitalizations in Brazil during 2000–2015. MethodsData on daily hospitalizations and weather variables were collected from 1814 cities, comprising 78.4% of Brazilian population. TV was defined as the standard deviation of daily minimum and maximum temperatures during exposure days. City-specific TV effect was estimated using a quasi-Poisson regression model, and then pooled at the national and regional level using meta-analysis. Stratified analyses were performed by sex, 10 age-groups, and 11 cause categories. Meta-regression was applied to city-year-specific estimates to examine the temporal change. ResultsThe estimate of TV effect peaked on 0–1 days' exposure, contributing to 3.5% [95% confidence interval (CI): 3.1–3.8%] of hospitalizations nationwide, equalling 221 (95%CI: 200–242) cases per 100,000 population annually. The effect estimate varied across 11 cause categories, which was strongest for respiratory admissions. Males, particular those 10–49 year old were more affected than females but there was no sex difference for the attributable hospitalization rate. The attributable rate for the under-fives was twice as high as for the elderly, and five times higher than in adults. The majority of the most affected cities were located in the central west and the inland of northeast. The risk of hospitalization related to TV showed a significant increase over the 16-year period at the national level. ConclusionsIn Brazil, the effect of TV on hospitalization is acute, and varies by spatial, sex, age, and cause category. Given there is no evidence regarding TV adaptation, hospitalization burden associated with TV is likely to further increase and warrants consideration when developing future public health policies in the context of climate change.

Realistic heat pulses protect frogs from disease under simulated rainforest frog thermal regimes

Abstract Recent emergences of fungal diseases have caused catastrophic global losses of biodiversity. Temperature is one of the most important factors influencing host–fungus associations but the effects of temperature variability on disease development are rarely examined. The chytrid pathogen Batrachochytrium dendrobatidis (Bd) has had severe effects on populations of hundreds of rainforest‐endemic amphibian species but we know little about the effects of rainforest‐specific host body temperature cycles on infection patterns. To address this challenge, we used body temperature regimes experienced in nature by frogs in the Australian Wet Tropics to guide a controlled experiment investigating the effects of body temperature fluctuations on infection patterns in a model host (Litoria spenceri), with emphasis on exposing frogs to realistic “heat pulses” that only marginally exceed the thermal optimum of the fungus. We then exposed cultured Bd to an expanded array of heat pulse treatments and measured parameters of population growth to help resolve the role of host immunity in our in vivo results. Infections developed more slowly in frogs exposed to daily 4‐hr heat pulses of 26°C or 29°C than in frogs in constant temperature treatments without heat pulses (control). Frogs that experienced heat pulses were also less likely to exceed infection intensities at which morbidity and mortality become likely. Ten of 11 (91%) frogs from the daily 29°C heat pulse treatment even cleared their infections after approximately 9 weeks. Cultured Bd also grew more slowly when exposed to heat pulses than in constant‐temperature control treatments, suggesting that mild heat pulses have direct negative effects on Bd growth in nature, but precluding us from determining whether there was a concurrent benefit of heat pulses to host immunity. Our results suggest that even in habitats where average temperatures may be suitable for fungal growth and reproduction, infection risk or the outcome of existing infections may be heavily influenced by short but frequent exposures to temperatures that only slightly exceed the optimum for the fungus. Our findings provide support for management interventions that promote warm microenvironments for hosts, such as small‐scale removal of branches overhanging critical habitat or provision of artificial heat sources. A plain language summary is available for this article.

Mathematical assessment of the role of temperature and rainfall on mosquito population dynamics.

A new stage-structured model for the population dynamics of the mosquito (a major vector for numerous vector-borne diseases), which takes the form of a deterministic system of non-autonomous nonlinear differential equations, is designed and used to study the effect of variability in temperature and rainfall on mosquito abundance in a community. Two functional forms of eggs oviposition rate, namely the Verhulst-Pearl logistic and Maynard-Smith-Slatkin functions, are used. Rigorous analysis of the autonomous version of the model shows that, for any of the oviposition functions considered, the trivial equilibrium of the model is locally- and globally-asymptotically stable if a certain vectorial threshold quantity is less than unity. Conditions for the existence and global asymptotic stability of the non-trivial equilibrium solutions of the model are also derived. The model is shown to undergo a Hopf bifurcation under certain conditions (and that increased density-dependent competition in larval mortality reduces the likelihood of such bifurcation). The analyses reveal that the Maynard-Smith-Slatkin oviposition function sustains more oscillations than the Verhulst-Pearl logistic function (hence, it is more suited, from ecological viewpoint, for modeling the egg oviposition process). The non-autonomous model is shown to have a globally-asymptotically stable trivial periodic solution, for each of the oviposition functions, when the associated reproduction threshold is less than unity. Furthermore, this model, in the absence of density-dependent mortality rate for larvae, has a unique and globally-asymptotically stable periodic solution under certain conditions. Numerical simulations of the non-autonomous model, using mosquito surveillance and weather data from the Peel region of Ontario, Canada, show a peak mosquito abundance for temperature and rainfall values in the range [Formula: see text]C and [15-35] mm, respectively. These ranges are recorded in the Peel region between July and August (hence, this study suggests that anti-mosquito control effects should be intensified during this period).