Effects Of Cold Temperatures Research Articles

Development and calibration of a model for the potential establishment and impact of Aedes albopictus in Europe

The Asian tiger mosquito (Aedes albopictus) is one of the most invasive disease vectors worldwide. The species is a competent vector of dengue, chikungunya, Zika viruses and other severe parasites and pathogens threatening human health. The capacity of this mosquito to colonize and establish in new areas (including temperate regions) is enhanced by its ability of producing diapausing eggs that survive relatively cold winters. The main drivers of population dynamics for this mosquito are water and air temperature and photoperiod. In this paper, we present a mechanistic model that predicts the potential distribution, abundance and activity of Asian tiger mosquito in Europe. The model includes a comprehensive description of: i) the individual life-history strategies, including diapause, ii) the influence of weather-driven individual physiological responses on population dynamics and iii) the density-dependent regulation of larval mortality rate. The model is calibrated using field data from several locations along an altitudinal gradient in the Italian Alps, which enabled accurate prediction of cold temperature effects on population abundance, including identification of conditions that prevent overwintering of the species. Model predictions are consistent with the most updated information on species’ presence and absence. Predicted population abundance shows a clear south-north decreasing gradient. A similar yet less evident pattern in the activity of the species is also predicted. The model represents a valuable tool for the development of strategies aimed at the management of Ae. albopictus and for the implementation of effective control measures against vector-borne diseases in Europe.

Lag effect of air temperature on the incidence of respiratory diseases in Lanzhou, China.

Previous studies have found that ambient temperature was associated with respiratory disease. However, little evidence is available in Lanzhou, a semi-arid region in northwest China, and respiratory disease is not well understood. This study evaluated the risk of outpatient visits for respiratory diseases associated with ambient temperatures from 2007 to 2016 in Lanzhou. We used a distributed lag non-linear model coupled with a generalized additive model to estimate the association between daily temperature and hospital visits for respiratory diseases in age- and sex-specific groups. Over 10years, 1,042,656 hospital visits were recorded for respiratory disease, the ratio between males and females was 1.21:1. The peak period of onset occurs from November of the current year to March of the following year. Both low and high temperatures were associated with an increased risk of hospital visits for respiratory illness. The results showed that a large temperature decrease was associated with a significant risk for respiratory disease, the maximum effect of a temperature drop was reached at lag 1~2days, the extreme low temperature (- 16°C) had the maximum RR at lag 1, and the RR value was 1.082 (95% CI 1.025-1.142). The high temperatures (23°C) had maximum RR for respiratory disease on the current day, and the RR value was 1.099 (95% CI 1.049-1.152). The high temperatures had acute and short-term effects and declined quickly over time, while the effects in low-temperature ranges were persistent over longer lag periods. Females suffered more from cold-associated morbidity than males. The effects of both hot and cold temperatures were greater among adolescents aged 6-14years. Our study suggests that ambient temperatures are associated with hospital visits for respiratory illness in Lanzhou, particularly for those who are female and young. Caregivers and health practitioners should be made aware of the potential threat posed by cold and hot temperatures.

Platelets Apoptosis and Clearance in The Presence of Sodium Octanoate during Storage of Platelet Concentrate at 4˚C.

Objective Platelet (PLT) storage at 4˚C has several benefits, however, it is accompanied by increased clearance of PLTs after transfusion. In this study, we evaluated the potential of sodium octanoate (SO) for reducing apoptosis and clearance rate of PLTs after long-term storage in cold. Materials and Methods In this experimental study, PLT concentrates (PCs) were stored for 5 days under the following three conditions: 20-24˚C, 4˚C, and 4˚C in the presence of SO. To measure the viability of PLTs, the water-soluble tetrazolium salt (WST-1) assay was performed. Phosphatidylserine (PS) exposure was determined on PLTs using flow cytometry technique. The amount of human active caspase-3 was determined in PLTs using an enzyme-linked immunosorbent assay. Additionally, the amount of PLT ingestion or clearance was determined by using HepG2 cell line. Results The viability was higher in the SO-treated PLTs compared to the other groups. The level of PS exposure on PLTs was lower in the SO-treated PLTs compared to the other groups. The amount of active caspase-3 increased in all groups during 5-day storage. The highest increase in the amount of caspase-3 levels was observed at cold temperature. However, PLTs kept at 4˚C in the presence of SO had a lower amount of active caspase-3 compared to PLTs kept at 4˚C. The amount of PLTs removal by HepG2 cells was increased for 4˚C-kept PLTs but it was lower for PLTs kept at 4˚C in the presence of SO but, the differences were not significant (P>0.05). ConclusionSO could partially moderate the effects of cold temperature on apoptosis and viability of platelets. It also decreases the ingestion rate of long-time refrigerated PLTs in vitro. Further studies using higher numbers of samples are required to demonstrate the effect of SO on reducing the clearance rate of PLTs.

A practical diagram to determine the residual longitudinal strength of grounded ship in Northern Sea Route

ABSTRACT In this study, a useful solution is proposed for assessing the safety of the ship’s hull damaged by grounding in Northern Sea Route (NSR) or Arctic sea. In particular, the residual ultimate longitudinal strength of grounding damaged ship can be predicted by the grounding damage index (GDI) concept. Due to the global warming effects, the Arctic glaciers have been gradually melting, and it may bring us the new North Pole routes. However, there are uncertainties on many causes that can lead to grounding accident of the commercial vessels. In this regard, residual ultimate longitudinal strength of grounding damaged commercial ship in Arctic sea is investigated. Five (5) temperatures: room temperature (RT), −20°C, −40°C, −60°C and −80°C were adopted to consider the cold temperature effect in NSR. The Panamax class oil tanker was selected for the investigation of residual ultimate longitudinal strength of grounding damaged ship. Fifty (50) reliable damage scenarios were adopted for the evaluation of structural health by utilising Residual strength versus GDI (R-D) diagram method. From this study, a modified R-D diagram is proposed which can consider grounding damage with cold temperature effect. The obtained outcome will be useful for assessing the safety of the grounded ships in Arctic sea region by measuring the grounding damage amount and surrounding air temperature.

Hypothermia induces changes in the alternative splicing pattern of cold-inducible RNA-binding protein transcripts in a non-hibernator, the mouse.

Cold-inducible RNA-binding protein (CIRBP) plays important roles in protection against harmful effects of cold temperature. We previously found that several splicing variants of CIRBP mRNA are constitutively expressed in the heart of non-hibernating euthermic hamsters and that one of the variants is predominantly expressed with remarkable reduction in the expression of other variants in hibernating hypothermic hamsters. The aim of this study was to determine whether the regulation of alternative splicing is a common function in a non-hibernator, the mouse. The expression of CIRBP mRNA was assessed by RT-PCR. In euthermic control mice, several splicing variants of CIRBP mRNA were detected in various organs. When hypothermia was induced in mice by using isoflurane anesthesia, the short form variant, which encodes full-length functional CIRBP, was predominantly detected. Keeping body temperature of anesthetized mice at 37°C prevented changes in the splicing pattern. Exposure of mice to a low temperature did not change the splicing pattern, suggesting that endogenous neuronal and/or humoral pathways activated in response to cold stimuli applied to the body surface play minor roles. In agreement with this, the shift in alternative splicing was reproduced in isolated leukocytes in vitro when they were incubated at 28°C. Since application of a TRPM8 or TRPA1 agonist at 37°C failed to promote the shift in the splicing pattern, it seems likely that cold-sensitive channels are not involved in the splicing regulation. Therefore, it is probable that a substantial reduction of temperature is a major cause of the regulation of alternative splicing of CIRBP transcripts. The regulatory system of CIRBP expression at the level of alternative splicing, which was originally discovered in the hibernating hamster, commonly exists in non-hibernators such as mice.

Temperature stress interferes with male reproductive system development in clementine (Citrus clementina Hort. ex. Tan.)

AbstractMale gametophyte development is a critical phase of the plant life cycle due to its high sensitivity to environmental stresses. The rise in the average global temperature, often accompanied by extreme fluctuations, has an important impact on biological processes. Among those, male gametophytes are particularly sensitive to temperature stress during flower bud development and anthesis. Male gametophyte development was extensively studied in several plant species, but little information is available about the effects of temperature stress on male gametophyte development in the genus Citrus. We evaluated the effects of cold and hot temperatures during microsporogenesis and microgametogenesis on one of the most economically valuable citrus species, the “Comune” clementine (Citrus clementina Hort. ex. Tan.). The effect of constant temperature on the androecium was evaluated by a time course histological analysis performed on the anthers and by monitoring in vitro pollen germination. The results revealed how suboptimal hot and cold temperatures induce drastic alterations on the morphology of the tapetal cells, microspores and mature pollen grains. Shifting from the optimal temperature affected the timing of starch depletion in the anther walls, such as epidermis, endothecium and middle layer, influencing the pollen germination rate and pollen tube growth. To the best of our knowledge this is the first study attempting to assess how temperature stress affects male reproductive development in citrus. A better understanding of the mechanisms underlining male sterility will provide novel insights to elucidate the physiology of this agronomical important quality trait.

Splenic Blood Flow Increases after Hypothermic Stimulus (Cold Pressor Test): A Perfusion Magnetic Resonance Study.

The Cold Pressor Test (CPT) is a novel diagnostic strategy to noninvasively assess the myocardial microvascular endothelial-dependent function using perfusion magnetic resonance imaging (MRI). Spleen perfusion is modulated by a complex combination of several mechanisms involving the autonomic nervous system and vasoactive mediators release. In this context, the effects of cold temperature on splenic blood flow (SBF) still need to be clarified. Ten healthy subjects were studied by MRI. MRI protocol included the acquisition of GRE T1-weighted sequence (“first pass perfusion”) during gadolinium administration (0.1mmol/kg of Gd-DOTA at flow of 3.0 ml/s), at rest and after CPT. Myocardial blood flow (MBF) and SBF were measured by applying Fermi function deconvolution, using the blood pool input function sampled from the left ventricle cavity. MBF and SBF values after performing CPT were significantly higher than rest values (SBF at rest: 0.65 ± 0.15 ml/min/g Vs. SBF after CPT: 0.90 ± 0.14 ml/min/g, p: <0.001; MBF at rest: 0.90 ± 0.068 ml/min/g Vs. MBF after CPT: 1.22 ± 0.098 ml/min/g, p<0.005). Both SBF and MBF increased in all patients during the CPT. In particular, the CPT-induced increase was 43% ± 29% for SBF and 36.5% ± 17% for MBF. CPT increases SBF in normal subjects. The characterization of a standard perfusion response to cold might allow the use of the spleen as reference marker for the adequacy of cold stimulation during myocardial perfusion MRI.

Oil Hydrocarbon Degradation by Caspian Sea Microbial Communities.

The Caspian Sea, which is the largest landlocked body of water on the planet, receives substantial annual hydrocarbon input from anthropogenic sources (e.g., industry, agriculture, oil exploration, and extraction) and natural sources (e.g., mud volcanoes and oil seeps). The Caspian Sea also receives substantial amounts of runoff from agricultural and municipal sources, containing nutrients that have caused eutrophication and subsequent hypoxia in the deep, cold waters. The effect of decreasing oxygen saturation and cold temperatures on oil hydrocarbon biodegradation by a microbial community is not well characterized. The purpose of this study was to investigate the effect of oxic and anoxic conditions on oil hydrocarbon biodegradation at cold temperatures by microbial communities derived from the Caspian Sea. Water samples were collected from the Caspian Sea for study in experimental microcosms. Major taxonomic orders observed in the ambient water samples included Flavobacteriales, Actinomycetales, and Oceanospirillales. Microcosms were inoculated with microbial communities from the deepest waters and amended with oil hydrocarbons for 17 days. Hydrocarbon degradation and shifts in microbial community structure were measured. Surprisingly, oil hydrocarbon biodegradation under anoxic conditions exceeded that under oxic conditions; this was particularly evident in the degradation of aromatic hydrocarbons. Important microbial taxa associated with the anoxic microcosms included known oil degraders such as Oceanospirillaceae. This study provides knowledge about the ambient community structure of the Caspian Sea, which serves as an important reference point for future studies. Furthermore, this may be the first report in which anaerobic biodegradation of oil hydrocarbons exceeds aerobic biodegradation.

The effects of meteorological variables on ambulance attendance for cardiovascular diseases in Rasht, Iran.

Climate change has a devastating effect on human societies, including their economic, cultural and health conditions. Our objective was to investigate the association between meteorological variables and ambulance attendance in the event of cardiovascular diseases using time-series analyses. We used a time series analysis to investigate the relationship between meteorological variables and ambulance attendance in the event of cardiovascular diseases from 2010 to 2015. To examine the effect of high temperatures on ambulance attendance, we investigated the relative risk of the daily volume of high temperature attendance, the 99th temperature percentile compared to the 75th temperature percentile. Upon examining the effect of cold temperatures on ambulance attendance, or the relative risk of the daily volume of attendance with low temperatures, the 1st temperature percentile compared to the 25th temperature percentile. In 1826 days, from March 21, 2010 to March 19, 2015, there were 7051 emergency calls for cardiovascular diseases. Significant variations were identified in the monthly (P < 0.001) and seasonal (P < 0.001) distributions. The highest seasonal incidence occurred in the winter and lowest was observed in the summer. With regard to association between cold temperature and calls for ambulance attendance in the event of cardiovascular diseases according to lag days, our findings showed a significant increase in lag 7 ((RR, 1.026; 95% CI, 1.003 to 1.050), lag 8 (RR, 1.023; 95% CI, 1.005to 1.041) and lag 9 (RR, 1.019; 95% CI, 1.002 to 1.036) respectively. These results suggest that the demand for an ambulance for cardiovascular diseases was higher in the cold weather and that humidity can increase this demand in the warm seasons.

Cold temperatures, stress, and violence

The relation between temperature and violence was found in many studies. However, the results of such studies demonstrated only that uncomfortably hot temperatures increase violence. There seem to be no data on the effect of cold temperatures. We studied the relation between temperature and violence for the Russian Federation because the Russian Federation is a country with huge climatic differences. Two types of the analysis of the data were applied. In Analysis 1 average yearly temperatures were used. For violent crimes a decrease in temperature resulted in the increase of the crimes after taking into account three socioeconomic variables. Analysis 2 was based on monthly data. Violence was high in winter and spring months but low in autumn months. In our opinion, the conventional models that are used to clarify the effect of hot temperatures cannot explain our results. We hypothesize that long periods of cold temperatures can be considered as mild chronic stress. Chronic stress may exert depression and depression is associated with irritability and anger. In some situations these emotions may stimulate violence. An increase in violence associated with city living and economic downturns may partially be a consequence of mild chronic stress.

Discrimination of viable and dead Vibrio parahaemolyticus subjected to low temperatures using Propidium Monoazide – Quantitative loop mediated isothermal amplification (PMA-qLAMP) and PMA-qPCR

The aim of this study was to determine the effect of cold (4 °C) and subzero (−18 °C, −45 °C) temperatures on the occurrence time of membrane damage to provide Propidium Monoazide (PMA) penetration of Vibrio parahaemolyticus inoculated to the sea bass. Direct plate counting (DPC) and PMA-based quantitative loop-mediated isothermal amplification (qLAMP) and qPCR was utilized for discrimination of dead and live bacteria on the designated storage days (1, 3, 7, and 14).The optimum amount of PMA was 50 μM for inhibition of amplification derived from dead cells in spiked samples. The number of live V. parahaemolyticus was detectable at the end of the 14. day using PMA-qLAMP and PMA-qPCR at all the temperatures. On the 7th day, culturability has lost at any of the storage temperatures and DPCs at −18 °C and −45 °C revealed a difference of about 1 log10 CFU/ml between 1st and 3rd days. The same difference was also observed in PMA–qLAMP and PMA–qPCR on the same days (0.59–0.95 log10 CFU/ml). Subzero temperatures have the highest rate of viability while causing the fastest decrease in culturability in sample groups as a result of the higher level of transition to VBNC state. qLAMP and qPCR methods in the PMA-treated and nontreated groups on the storage days at all temperatures gave similar results (p > 0.05).

Simplified model and analysis for the performance of Hofbauer–Vuilleumier heat pump

Vuilleumier heat pumps can reduce the consumption of fossil combustion and thus have huge potential for applications in heating systems. However, it receives less attentions. In this paper, a Vuilleumier heat pumps with alternate move-and-stop motions (Hofbauer–Vuilleumier heat pump) was studied. A theoretical adiabatic model and a simple adiabatic model were derived. Both models were compared to the numerical adiabatic model and isothermal model. The results of theoretical adiabatic model agreed well with that of the numerical adiabatic model in terms of Qh, Qc, COP, pressure and temperature. The accuracy of the simple adiabatic model was relatively worse than the theoretical adiabatic model but much higher than the isothermal model. Furthermore, the effects of hot, warm and cold temperatures, initial pressure, dead volumes and various heat losses (regenerators’ heat losses, displacers’ shuttle losses, pumping losses and axial conduction losses) on the performance were investigated.

The surface markers and survival rate of platelets during storage at 4°C: The influence of sodium octanoate

Background: Storage of platelet concentrates (PCs) at room temperature (20-24°C) limits its storage time to 5 days due to the destructive effects of platelet storage lesion (PSL) and bacterial contamination. Although prolonged storage of platelets (PLTs) at 4°C reduces the likelihood of bacterial contamination and PSL levels, it is accompanied by an increase in the clearance rate and changes in the surface markers of PLTs. The goal of this study was to evaluate the effects of sodium octanoate (SO) as a stabilizer on PLTs during storage at 4°C. Materials and Methods: In this experimental study, PCs were divided into three portions and stored for 5 days at 3 different conditions, including 20-24°C, 4°C temperature, and 4°C in presence of SO. PLTs enumeration was performed using an automated hematology analyzer. To measure the metabolic activity and survival rate of PLTs, the water-soluble tetrazolium salt (WST-1) assay was performed. The activity of lactate dehydrogenase enzyme (LDH) was measured by a biochemical analyzer. Additionally, the levels of PLT glycoprotein Ibα (GPIbα) and CD62P (P-selectin) were measured on PLTs by flow cytometry technique. Results: PLTs count was higher in SO-treated (4°C) PLTs than two other studied samples. Additionally, the viability was higher in the SO-treated PLTs than that in other groups. LDH amount was lower in the SO-treated PLTs than that in other groups (P&gt;0.05). GPIbα expression was significantly higher in SO-treated PLTs than that other groups (P&lt;0.05). On the other hand, the expression of CD62P was lower at 4°C in PLTs in the presence of SO (P&gt;0.05). Conclusions: SO could modulate the effects of cold temperatures on PLTs. Furthermore, we found that the survival of platelets was better maintained in the presence of SO at 4°C.

Cold acclimation triggers lipidomic and metabolic adjustments in the spotted wing drosophila Drosophila suzukii (Matsumara).

Chronic cold exposure is detrimental to chill susceptible insects that may accumulate chill injuries. To cope with deleterious effects of cold temperature, insects employ a variety of physiological strategies and metabolic adjustments, such as production of cryoprotectants, or remodeling of cellular membranes. Cold tolerance is a key element determining the fundamental niche of species. Because Drosophila suzukii is an invasive fruit pest, originating from East Asia, knowledge about its thermal biology is urgently needed. Physiological mechanisms underlying cold tolerance plasticity remain poorly understood in this species. Here, we explored metabolic and lipidomic modifications associated with the acquisition of cold tolerance in D. suzukii using Omics technologies (LC- and GC-MS/MS). In both cold-acclimated males and females, we observed physiological changes consistent with homeoviscous/homeophasic adaptation of membranes: reshuffling of phospholipid head groups and increasing unsaturation rate of fatty acids. Modification of fatty acids unsaturation were also observed in triacylglycerides, which would likely increase accessibility of lipid reserves. At the metabolic level, we observed clear-cut differentiation of metabolic profiles with cold-acclimated metabotypes showing accumulation of several potential cryoprotectants (sugars and amino acids). Metabolic pathway analyses indicated a remodeling of various processes, including purine metabolism and aminoacyl tRNA biosynthesis. These data provide a large-scale characterization of lipid rearrangements and metabolic pathway modifications in D. suzukii in response to cold acclimation and contribute to characterizing the strategies used by this species to modulate cold tolerance.

Snow roosting reduces temperature-associated stress in a wintering bird.

Animals in temperate northern regions employ a variety of strategies to cope with the energetic demands of winter. Behavioral plasticity may be important, as winter weather conditions are increasingly variable as a result of modern climate change. If behavioral strategies for thermoregulation are no longer effective in a changing environment, animals may experience physiological stress, which can have fitness consequences. We monitored winter roosting behavior of radio-tagged ruffed grouse (Bonasa umbellus), recorded snow depth and temperature, and assayed droppings for fecal corticosterone metabolites (FCM). Grouse FCM levels increased with declining temperatures. FCM levels were high when snow was shallow, but decreased rapidly as snow depth increased beyond 20cm. When grouse used snow burrows, there was no effect of temperature on FCM levels. Snow burrowing is an important strategy that appears to allow grouse to mediate the possibly stressful effects of cold temperatures. This is one of the first studies to explore how variable winter weather conditions influence stress in a free-living cold-adapted vertebrate and its ability to mediate this relationship behaviorally. Animals that depend on the snowpack as a winter refuge will likely experience increased stress and possible fitness costs resulting from the loss of snow cover due to climate change.

Effects of cold temperature and snowfall on stroke mortality: A case-crossover analysis

BackgroundWe sought to determine if cold temperature and snowfall are independently associated with stroke mortality, and whether effects differ between hemorrhagic and ischemic stroke. Materials and methodsWe conducted a case-crossover study of 13,201 stroke deaths utilizing weather records between the months of November and April for Quebec, Canada from 1981 to 2015. We compared exposure to cold temperature and snowfall with controls days when stroke death did not occur. We computed odds ratios (OR) and 95% confidence intervals (CI) for the association of minimum temperature and duration of snowfall with stroke, adjusted for change in barometric pressure and relative humidity. ResultsThe likelihood of mortality the day following exposure to cold temperature was elevated for hemorrhagic stroke in men, independent of snowfall. Relative to 0 °C, a temperature of −20 °C was associated with 1.17 times the odds of hemorrhagic stroke death (95% CI 1.04–1.32). An independent effect of snowfall was also present in men, with 12 h of snowfall associated with 1.12 times the odds of hemorrhagic stroke death (95% CI 1.00–1.24) compared with no snowfall. There was no evidence of an increased risk in women. Cold temperature and snowfall were not associated with ischemic stroke death in either men or women. ConclusionOur results suggest that cold temperature and snowfall are independent risk factors for death from hemorrhagic stroke in men. These findings imply that interventions to prevent fatal hemorrhagic stroke during winter should include both cold temperature exposure and snowfall in men.

Cold temperature effects on the impact resistance of thin, lightweight UHPFRC panels

In this study, lightweight armoured panels were designed using ultra high performance fibre reinforced concrete (UHPFRC) and experimental testing was conducted. Panels were cast with the dimensions of 1040 mm × 535 mm × 38 mm to limit their mass to approximately 50 kg and allow them to be carried by two individuals. These panels were designed to be a part of a modular protective system that could be used to protect key infrastructure and assets in a deployed military environment. Experimental quasi-static and dynamic tests were conducted. Quasi-static tests were done to determine a baseline loading capacity of the panels using three-point flexural bending. Dynamic testing was conducted using a pendulum-type impact hammer that could vary the amount of impact energy by altering the drop height of the hammer. Residual panel strength was determined after each panel was tested dynamically by using the same three-point flexural bending test that was used for quasi-static testing. All tests were conducted with panels at ambient laboratory temperatures and extreme cold temperatures to simulate Arctic conditions. Panels were tested at Arctic temperatures to determine their feasibility protecting critical infrastructure in Canada's Arctic. The testing demonstrated that the UHPFRC panels could resist impact loads with energies up to 2000 J without complete failure. Panels were not adversely affected by the extreme cold temperatures and in fact displayed increased effectiveness at cold temperatures. Single degree of freedom (SDOF) modelling was used to predict panel deflections based on various impact energies. The model developed can accurately predict peak displacements based on impact loading data.

Difference in temporal variation of temperature-related mortality risk in seven major South Korean cities spanning 1998–2013

Temporal variation of temperature-related mortality risk is an important issue in climate change era. However, difference in this temporal variation across cities in South Korea remains unclear. The aim of this study was to explore whether temporal variation might differ spatially across seven metropolitan cities of Korea during the period of 1998–2013. We estimated cumulative associations between temperature (up to previous 14 days of exposure) and all-cause mortality, and compared cumulative associations between the first eight years (1998–2005) and the last eight years (2006–2013). Multivariate meta-regression analysis was performed to investigate what factors might be associated with spatial and temporal variation in cumulative associations. We found that Busan, Daegu, and Gwangju experienced decrease in heat effect from 1998–2005 to 2006–2013, while Incheon experienced increase in heat effect. By comparing mortality risk at 99th percentile of temperature to mortality risk at minimum mortality temperature, percentage increase of mortality risk changed from 4.8% (95% CI: −1.3, 11.3) to 0.4% (95% CI: −6.0, 7.4) in Busan, from 17.2% (95% CI: 10.2, 24.7) to 4.0% (95% CI: −1.4, 9.8) in Daegu, from 20.3% (95% CI: 11.5, 29.7) to 2.2% (95% CI: −3.5, 8.3) in Gwangju, and from 3.5% (95% CI: 0.2, 6.8) to 7.9% (95% CI: 5.0, 10.9) in Incheon, respectively. Change in average temperature from 1998–2005 to 2006–2013 was negatively associated with change in heat effect even though average temperature in most of the cities fluctuated over time. We also found that all seven cities had decrease in effect of moderate cold temperature from 1998–2005 to 2006–2013. Such decrease was associated with improvement in medical resources. Results of this study suggest that plans for adaptation to temperature-related risks should differ across populations because adaptation to temperature varies across populations and within the same population over different time.

Laboratory investigation of the consolidation resistance of a rubble river ice cover with a thermally grown solid crust

River ice behaviour during freeze-up depends on a complex relationship between dynamic and thermal processes. This study investigates the effects of cold ambient air temperatures on the ability of a rubble ice cover to resist consolidation (mechanical thickening) under externally applied forces. An experimental apparatus was constructed in a refrigerated room at the University of Manitoba. The apparatus consists of a translating plate that was used to deform a floating rubble ice cover in a waterproof tank. Prior to resistance testing, the ice cover was exposed to an ambient air temperature of −10.5 °C for a specified duration. During this time, the interstitial water between the rubble pieces at the surface froze, creating a solid crust that solidified a portion of the rubble surface. Instruments were used to measure the displacement of the plate and resisting force generated by the ice cover during the resistance testing phase. Results indicate that even short durations of freezing (less than two hours) have a considerable impact on the peak resistance of an ice cover. The force required to consolidate a 155 mm thick rubble ice cover exposed to an ambient air temperature of −10.5 °C for two hours was over 30 times that of an equivalent unfrozen accumulation of rubble ice. The peak resistance of a cover comprising rubble ice with a solid crust was found to be much greater than the sum of the individual contributions of the rubble and solid ice layers considered separately. Results from this study highlight the significant effect of thermal processes on ice dynamics, and can inform future research efforts in incorporating these processes into numerical river ice models.

The anatomy of »blue ring« in the wood of Pinus nigra

Tree-ring features are widely used to identify specific climate, environment and stress events affecting plant life. Cold temperatures can mainly affect the last phase of cell differentiation by interfering in the process of cell wall lignin deposition. Recently, it was found out that the effect of cold temperature on lignification is visible in wood microsections double stained with astra blue which stains cellulose, and red safranin which stains lignin. This new tree-ring feature was called »blue ring«. In this study, we investigated the anatomical morphology of blue rings in transverse and longitudinal wood microsections of three European black pine trees (Pinus nigra Arnold) growing above the treeline. We aim to understand if the lack of lignification is consistent along the entire tracheid length and whether or not pits, responsible for water transport from one tracheid to another, are lignified. The results show that the lack of lignification extends along the entire tracheids cell wall, including bordered pits. Based on our observations we speculate that blue ring occurrence decreases the safety of water transport and wood mechanical properties.