Seasonal Temperature Fluctuations Research Articles

Protein expression plasticity contributes to heat and drought tolerance of date palm

Climate change is increasing the frequency and intensity of warming and drought periods around the globe, currently representing a threat to many plant species. Understanding the resistance and resilience of plants to climate change is, therefore, urgently needed. As date palm (Phoenix dactylifera) evolved adaptation mechanisms to a xeric environment and can tolerate large diurnal and seasonal temperature fluctuations, we studied the protein expression changes in leaves, volatile organic compound emissions, and photosynthesis in response to variable growth temperatures and soil water deprivation. Plants were grown under controlled environmental conditions of simulated Saudi Arabian summer and winter climates challenged with drought stress. We show that date palm is able to counteract the harsh conditions of the Arabian Peninsula by adjusting the abundances of proteins related to the photosynthetic machinery, abiotic stress and secondary metabolism. Under summer climate and water deprivation, these adjustments included efficient protein expression response mediated by heat shock proteins and the antioxidant system to counteract reactive oxygen species formation. Proteins related to secondary metabolism were downregulated, except for the P. dactylifera isoprene synthase (PdIspS), which was strongly upregulated in response to summer climate and drought. This study reports, for the first time, the identification and functional characterization of the gene encoding for PdIspS, allowing future analysis of isoprene functions in date palm under extreme environments. Overall, the current study shows that reprogramming of the leaf protein profiles confers the date palm heat- and drought tolerance. We conclude that the protein plasticity of date palm is an important mechanism of molecular adaptation to environmental fluctuations.

Thermal biology of Liolaemus scapularis (Iguania:Liolaemidae) from argentinian northwest.

Thermal traits knowledge is elemental to forecasting the impacts of environmental change on lizard diversity. Daily and seasonal environmental temperature fluctuations are amplified in desert and semi-desert species. As ectotherms, they can ameliorate physiological constrains through behavioral thermoregulation. Herein, we explored the thermal biology and behavioral related aspects of the endangered sand lizard Liolaemus scapularis and compared it between austral spring and summer seasons. The study was carried out in a north sector of Medanos de Cafayate in the SW of Salta province, Argentina. Mean field-body temperature (Tb) of L. scapularis was 35.72°C ranging from 29.10 to 41.10°C. Regression analyzes showed that substrate temperature (Ts) was the parameter that best explained the variability of the Tb. Body temperature in spring was only positively related to Ts, whereas in summer the Tb was positively related to air temperature (Ta). Despite GLMs indicated that the Tb of L. scapularis result statistically unchanged through seasons sampled and sexes, micro-environmental temperatures were different for males and females between sampled seasons. The behavioral thermoregulation trait assessed, sun exposure, revealed that the use of patches with different sun input varied with temperature parameters and between seasons. This behavioral trait seems to have a crucial role in the thermal strategy of these lizards in order to maintain an optimal homeostatic state avoiding overheating; still the Tb recorded for the studied population places Liolaemus scapularis in the upper range for the genus. Our results suggest that the species is an active thermoregulator with a hit gain through sand conduction mainly, a relevant shuttling behavior and seasonal intraspecific shifts.

Overwintering conditions impact insulin pathway gene expression in diapausing Megachile rotundata

Diapause is a non-feeding state that many insects undergo to survive the winter months. With fixed resources, overall metabolism and insulin signaling (IIS) are maintained at low levels, but whether those change in response to seasonal temperature fluctuations remains unknown. The focus of this study was to determine 1) how genes in the insulin signaling pathway vary throughout diapause and 2) if that variation changes in response to temperature. To test the hypothesis that expression of IIS pathway genes vary in response to temperature fluctuations during overwintering, alfalfa leafcutting bees, Megachile rotundata, were overwintered at either a constant 4 °C in the lab or in naturally fluctuating temperatures in the field. Expression levels of genes in the IIS pathway, cell cycle regulators, and transcription factors were measured. Overall our findings showed that a few key targets of the insulin signaling pathway, along with growth regulators, change during overwintering, suggesting that only cell cycle regulators, and not the IIS pathway as a whole, change across the phases of diapause. To answer our second question, we compared gene expression levels between temperature treatments at each month for a given gene. We observed significantly more differences in expression of IIS pathway targets, indicating that overwintering conditions impact insulin pathway gene expression and leads to altered expression profiles. With differences seen between temperature treatment groups, these findings indicate that constant temperatures like those used in agricultural storage protocols, lead to different expression profiles and possibly different diapause phenotypes for alfalfa leafcutting bees.

Tundra Type Drives Distinct Trajectories of Functional and Taxonomic Composition of Arctic Fungal Communities in Response to Climate Change - Results From Long-Term Experimental Summer Warming and Increased Snow Depth.

The arctic tundra is undergoing climate-driven changes and there are serious concerns related to the future of arctic biodiversity and altered ecological processes under possible climate change scenarios. Arctic land surface temperatures and precipitation are predicted to increase further, likely causing major transformation in terrestrial ecosystems. As a response to increasing temperatures, shifts in vegetation and soil fungal communities have already been observed. Little is known, however, how long-term experimental warming coupled with increased snow depth influence the trajectories of soil fungal communities in different tundra types. We compared edaphic variables and fungal community composition in experimental plots simulating the expected increase in summer warming and winter snow depth, based on DNA metabarcoding data. Fungal communities in the sampled dry and moist acidic tundra communities differed greatly, with tundra type explaining ca. one-third of compositional variation. Furthermore, dry and moist tundra appear to have different trajectories in response to climate change. Specifically, while both warming and increased snow depth had significant effects on fungal community composition and edaphic variables in dry tundra, the effect of increased snow was greater. However, in moist tundra, fungal communities mainly were affected by summer warming, while increased snow depth had a smaller effect and only on some functional groups. In dry tundra, microorganisms generally are limited by moisture in the summer and extremely low temperatures in winter, which is in agreement with the stronger effect of increased snow depth relative to warming. On the contrary, moist tundra soils generally are saturated with water, remain cold year-round and show relatively small seasonal fluctuations in temperature. The greater observed effect of warming on fungi in moist tundra may be explained by the narrower temperature optimum compared to those in dry tundra.

Increasing the Bearing Capacity and Durability of Building Foundations on Frozen Soils

The article considers the behavior of pile foundations of buildings constructed on permafrost soils with the preservation of the frozen state, depending on the methods of cooling the base: surface cooling using a cold underfloor space and deep cooling using the seasonal cooling devices (SCD) located along the perimeter of the building together with effective thermal insulation of the base. It is shown that in the first case, during longterm operation of piles, periodic seasonal fluctuations in temperature and stresses in the upper layers of the base can lead to a significant decrease in the bearing capacity. In the second case, the amplitude of temperature fluctuations in the frozen base is significantly reduced. Due to the stabilization of the annual temperature mode, not only the reliability and bearing capacity of pile foundations increase, but also the use of a foundation slab resting on frozen soils becomes possible.

Natural ultraviolet radiation exposure alters photosynthetic biology and improves recovery from desiccation in a desert moss.

Plants in dryland ecosystems experience extreme daily and seasonal fluctuations in light, temperature, and water availability. We used an in situ field experiment to uncover the effects of natural and reduced levels of ultraviolet radiation (UV) on maximum PSII quantum efficiency (Fv/Fm), relative abundance of photosynthetic pigments and antioxidants, and the transcriptome in the desiccation-tolerant desert moss Syntrichia caninervis. We tested the hypotheses that: (i) S. caninervis plants undergo sustained thermal quenching of light [non-photochemical quenching (NPQ)] while desiccated and after rehydration; (ii) a reduction of UV will result in improved recovery of Fv/Fm; but (iii) 1 year of UV removal will de-harden plants and increase vulnerability to UV damage, indicated by a reduction in Fv/Fm. All field-collected plants had extremely low Fv/Fm after initial rehydration but recovered over 8 d in lab-simulated winter conditions. UV-filtered plants had lower Fv/Fm during recovery, higher concentrations of photoprotective pigments and antioxidants such as zeaxanthin and tocopherols, and lower concentrations of neoxanthin and Chl b than plants exposed to near natural UV levels. Field-grown S. caninervis underwent sustained NPQ that took days to relax and for efficient photosynthesis to resume. Reduction of solar UV radiation adversely affected recovery of Fv/Fm following rehydration.

The critical thermal maximum of diving beetles (Coleoptera: Dytiscidae): a comparison of subterranean and surface-dwelling species

Thermal tolerance limits in animals are often thought to be related to temperature and thermal variation in their environment. Recently, there has been a focus on studying upper thermal limits due to the likelihood for climate change to expose more animals to higher temperatures and potentially extinction. Organisms living in underground environments experience reduced temperatures and thermal variation in comparison to species living in surface habitats, but how these impact their thermal tolerance limits are unclear. In this study, we compare the thermal critical maximum (CTmax) of two subterranean diving beetles (Dytiscidae) to that of three related surface-dwelling species. Our results show that subterranean species have a lower CTmax (38.3-39.0°C) than surface species (42.0-44.5°C). The CTmax of subterranean species is ∼10°C higher than the highest temperature recorded within the aquifer. Groundwater temperature varied between 18.4°C and 28.8°C, and changes with time, depth and distance across the aquifer. Seasonal temperature fluctuations were 0.5°C at a single point, with the maximum heating rate being ∼1000x lower (0.008°C/hour) than that recorded in surface habitats (7.98°C/hour). For surface species, CTmax was 7-10°C higher than the maximum temperature in their habitats, with daily fluctuations from ∼1°C to 16°C and extremes of 6.9°C and 34.9°C. These findings suggest that subterranean dytiscid beetles are unlikely to reach their CTmax with a predicted warming of 1.3-5.1°C in the region by 2090. However, the impacts of long-term elevated temperatures on fitness, different life stages and other species in the beetle's trophic food web are unknown.

Microclimate drives intraspecific thermal specialization: conservation perspectives in freshwater habitats.

Endemic and relict species are often confined to ecological refugia or over fragmented distributions, representing priority conservation subjects. Within these sites, the individual population may realize distinct niches to a varying degree of specialization. An emblematic example is provided by freshwater species segregated in thermal-mineral springs, where individuals may face highly diverse microclimates in limited geographic areas. Downscaling the characterization of physiological traits to microclimatic niches becomes pivotal to adopt effective conservation measures in these heterogeneous habitats. Melanopsis etrusca (Brot, 1862) is an endangered relict snail endemic to a small number of thermal-mineral streams in central Italy. Here we describe the thermal tolerance of two populations of M. etrusca inhabiting streams with distinctly different thermal regimes, investigating the extent of physiological and behavioural specialization to such diverse microclimatic niches. The comparison of oxygen consumption rates of a population dwelling in temperate streams, characterized by seasonal temperature fluctuations (12-27°C), with a population experiencing constantly hot water (35-38°C) revealed the absence of any seasonal or geographic effect on metabolic compensation. Conversely, mobility performances were maximized in the population inhabiting the hot stream. Interestingly, here, the snails exhibited emersion behaviour outside the water, triggered by temperatures above 37°C. In the field, individuals of this population are observed inactive on stream banks, conceivably to minimize the metabolic cost that otherwise would be induced by remaining in the hot water. Only a few individuals from the temperate stream exhibited the same behaviour when exposed to elevated temperatures, suggesting the exaptation of a pre-existing trait during the evolutionary process of adaptation to hot waters. The present results provide elements for the best practice in future programmes aimed at reintroducing stocks of threatened species across heterogeneous habitats. Our study further underlines the relevance of downscaling data collection for endangered species conservation in order to recognize microclimatic specializations.

МОДЕЛИ СИСТЕМ КВАЗИПЕРИОДИЧЕСКИХ ПРОЦЕССОВ НА ОСНОВЕ ЦИЛИНДРИЧЕСКИХ И КРУГОВЫХ ИЗОБРАЖЕНИЙ

The behavior of objects in many practical situations has a quasiperiodic character - the presence of noticeable periodicity with random variations of quasiperiods. For example, noise and vibration of an aircraft engine, hydroelectric unit, seasonal and daily fluctuations in atmospheric temperature, etc. In this case, the object can have several parameters, therefore the object is described by a system of several time series, that is, several random processes. The emerging monitoring tasks (assessing the state of an object and its forecast) require setting a model of such a system of processes and identifying it for a particular object based on the results of its observations. In this paper, to represent a quasi-periodic process, an autoregressive model is used in the form of sweeps of several cylindrical or circular images along a spiral. Choosing the values of a small number of parameters of this model, one can describe and simulate a wide class of systems of quasiperiodic processes. The problem of identifying a model is considered, that is, determining the values of its parameters at which it, in a certain sense, best corresponds to the actually observed process. This problem is solved using a pseudo-gradient adaptive procedure, the advantage of which is its real-time operation with low computational costs.

Seasonal variation of polycyclic aromatic hydrocarbon metabolites in bile of white perch Morone americana from two Chesapeake Bay tributaries.

Polycyclic aromatic hydrocarbon (PAH) accumulation in the bile is a reliable biomarker of recent exposure to environmental PAH and elevated concentrations have been identified as significant risk factors for hepatic disease in some fish species. Recent surveys (spring 2019) revealed a high incidence of hepatic lesions in white perch Morone americana from Chesapeake Bay, but this initial survey did not detect an association between PAH metabolites and lesions. Seasonal sampling of fish was extended through the winter 2020 to increase the metabolite and hepatic lesion database and better understand annual PAH exposures to white perch. Naphthalenes, phenanthrenes, and benzo[a]pyrenes (equivalents) were analyzed in bile specimens (n = 400) using high-performance liquid chromatography with fluorescence detection. Mean concentrations of metabolites were highest in fish collected from the urbanized Severn River in summer and were lowest in fish from the more rural Choptank River in winter. Variance in metabolite concentrations were primarily due to location and season. Seasonal fluctuations in water temperature, river discharge, or feeding status had little influence on the pattern of metabolite concentrations observed. The results suggest higher exposures of fish to environmental PAH in the more developed Severn River with significant increases during summer, which could correspond to a spike in seasonal recreational motor boat use or other human activities. A better understanding of the factors that contribute to variability in PAH metabolism and the enterohepatic biliary circulation in white perch will improve the usefulness of biliary metabolites as a biomarker of PAH exposure in Chesapeake Bay and elsewhere.

Seasonal temperature waves in the ground, nonperiodic case

Seasonal fluctuations in soil temperature at a depth of several meters are considered. It is assumed that the temperature of the earth surface changes strictly periodically. Then, according to the Fourier law, the soil temperature at depth will also change periodically with a smaller amplitude and time lag. What happens if we let the temperature on the surface deviate from the strict periodicity at some point in time? How will the nature of soil temperature fluctuations change at depth? Two types of deviations of the surface temperature from the periodic law are considered: 1) A sharp cold snap. For 30 days, the temperature of the earth surface is -30оC and 2) Warm winter. It is assumed that the temperature of the earth surface is zero during the winter months. Graphs of temperature changes at different depths in both cases are plotted. Conclusions are drawn about the duration of the period of noticeable deviations and the magnitude of the temperature deviation from the normal value.

ESTIMATING THE INFLUENCE OF SOLAR RADIATION AT DIFFERENT SEASONS ON THE MODE OF DEFORMATION OF A SPAN STRUCTURE WITH AN ORTROTROPIC PLATE

<p>The article studies the effect of solar radiation at different seasons on the mode of deformation (MD) of a span structure with an orthotropic plate. The temperature fields of the elements of the structure were measured during daylight hours at different times of year at various air temperatures and sun positions. Cases were identified in which it is necessary to clarify the temperature values of the asphalt concrete road surfacing and the main beams obtained using a non-contact pyrometer, and by measuring the temperature with a contact thermometer.</p> <p>During the year the elements of the span are in a wide temperature range. Using the developed finite element model of the span, taking into account the layers of road surfacing, the MD calculations were performed for each case of exposure to solar radiation according to the corrected results of field measurements. An analysis of the results of numerical studies allows us to conclude that diurnal and seasonal temperature fluctuations create significant additional stresses in the span, which should be taken into account when calculating the MD of spans of road bridges.</p>

Preparatory immunity: Seasonality of mucosal skin defences and Batrachochytrium infections in Southern leopard frogs.

Accurately predicting the impacts of climate change on wildlife health requires a deeper understanding of seasonal rhythms in host-pathogen interactions. The amphibian pathogen, Batrachochytrium dendrobatidis (Bd), exhibits seasonality in incidence; however, the role that biological rhythms in host defences play in defining this pattern remains largely unknown. The aim of this study was to examine whether host immune and microbiome defences against Bd correspond with infection risk and seasonal fluctuations in temperature and humidity. Over the course of a year, five populations of Southern leopard frogs (Rana [Lithobates] sphenocephala) in Tennessee, United States, were surveyed for host immunity, microbiome and pathogen dynamics. Frogs were swabbed for pathogen load and skin bacterial diversity and stimulated to release stored antimicrobial peptides (AMPs). Secretions were analysed to estimate total hydrophobic peptide concentrations, presence of known AMPs and effectiveness of Bd growth inhibition in vitro. The diversity and proportion of bacterial reads with a 99% match to sequences of isolates known to inhibit Bd growth in vitro were used as an estimate of predicted anti-Bd function of the skin microbiome. Batrachochytrium dendrobatidis dynamics followed the expected seasonal fluctuations-peaks in cooler months-which coincided with when host mucosal defences were most potent against Bd. Specifically, the concentration and expression of stored AMPs cycled synchronously with Bd dynamics. Although microbiome changes followed more linear trends over time, the proportion of bacteria that can function to inhibit Bd growth was greatest when risk of Bd infection was highest. We interpret the increase in peptide storage in the fall and the shift to a more anti-Bd microbiome over winter as a preparatory response for subsequent infection risk during the colder periods when AMP synthesis and bacterial growth is slow and pathogen pressure from this cool-adapted fungus is high. Given that a decrease in stored AMP concentrations as temperatures warm in spring likely means greater secretion rates, the subsequent decrease in prevalence suggests seasonality of Bd in this host may be in part regulated by annual immune rhythms, and dominated by the effects of temperature.

Season dynamics of microclimate parameters in the premises for keeping suckling sows farm with different ventilation systems

The article investigated the dependence of the microclimate indicators in the premises for keeping suckling sows on the design features of the ventilation system. The annual dynamics of seasonal temperature fluctuations in both premises of the reproducer of the farm, as well as in the zone of piglets' vital activity, was recorded within the normal range. At the same time, when using the classical type of ventilation, the temperature indicators were significantly higher in summer compared to similar values in premises with a geothermal type of ventilation. At the same time, the amplitude of fluctuations in the annual dynamics of the piglet den temperature was higher in premises with an experimental type of ventilation relative to the traditional one and with a slight relative excess of the optimal value of the indicator by 0,1 ° C in the spring months. The temperature regime of the den of sows both in the study and in the control premises during the study period was characterized by uneven differences in off-season indicators: when using classical ventilation, the peak fell in the summer period, when using ventilation with underground air supply, in winter, however, without exceeding the optimal values. The air velocity in both rooms increased during the summer months. At the same time, with the traditional system for creating a microclimate, a stable reliable excess of this indicator relative to the values of the studied system was recorded, as well as its excess of the norm in summer. For the studied system with underground air supply, on the contrary, low values were noted and extremely low in the winter season. Both ventilation systems ensured optimal air humidity during the study period. The carbon dioxide content tended to increase in the autumn months in both premises, however, it exceeded the norm only when using traditional ventilation during this period – by 0,02% vol. Average values of ammonia content were kept in the optimal zone during all seasons with a slight increase in concentrations in autumn. However, the experimental microclimate system allowed a significantly higher NH3 content than in control premises system in the summer months at 1,99 mg/m3 or 150,09%. The hydrogen sulfide content was optimal for both premises during the year. But the premises where the investigated air preparation system "Exatop" was installed significantly higher in the concentration of H2 S, by 64,81% (p<0,001) in spring, by 61,14% (p<0,001) in summer and by 43,00% (p<0,001) in autumn, relative to premises with a traditional air preparation system. Despite the shown dependence of the microclimate indicators on the type of ventilation, it should be noted that it is important to continue further studies of the influence of these factors. Key words: sow, piglet, type of ventilation, multiple births, piglet nest weight, safety, season.

A new approach to modelling of seasonal soil temperature fluctuations and their impact on the performance of a shallow borehole heat exchanger

A borehole heat exchanger (BHE) could be used in heating and cooling systems as the ground temperature is normally higher than the average air temperature in winter and lower in summer. This difference in the temperature can be used to improve the efficiency of air conditioning systems (in summer) and heat pumps (in winter). The performance of a BHE is influenced by soil temperature that may have significant seasonal changes. These changes were largely ignored in previous BHE modelling approaches being a source for large errors in theoretical predictions. This paper presents a new internal source term approach to account for the (seasonal) fluctuation in soil temperature on a shallow BHE's performance. The proposed model is able to consider the heat flow in multi-ground-layers. The governing equations of the model are solved by using explicit finite different method. The model is validated using experimental data. The simulated soil temperatures with and without the internal heat source term showed that the maximum relative errors are 3.7% and 14% respectively. The use of high thermal conductivity grout resulted in a decrease in the borehole thermal resistance. The outlet fluid temperature under the continuous operation mode is higher than that operated under the intermittent mode.

Using Amaranth as a Model Plant for Evaluating Imperfect Storages: Assessment of Solar-refrigerated and Evaporatively-cooled Structures in India

Some storages have limited control over their internal environment and undergo daily and seasonal fluctuations in both temperature and humidity, which cause variation in the metabolic activity of stored products. As a result, it is difficult to assess and compare the performance of these imperfect storages using measures of environmental control. We propose using measures of plant senescence as a proxy for estimating storage performance of these “imperfect” storages based on the premise that physiological processes integrate changes of temperature and/or humidity in a predictable, mathematically describable manner. We evaluated amaranth (Amaranthus tricolor L.) as a model plant for evaluating imperfect storages using a red-leaf cultivar Pusa lal chaulai and a green-leaf cultivar Pusa kiran. Amaranth is a leafy vegetable grown worldwide and is a highly nutritious and versatile food. Cumulative respiration, a measure of integrated metabolic activity, was regressed against leaf abscission, chlorophyll loss, and leaf yellowing of amaranth stems for four storages having different, variable, temperature profiles. Storages included 1) an evaporatively cooled (EC) structure; 2) a solar-refrigerated and evaporatively cooled (SREC) structure; 3) an uncooled laboratory (UL); and 4) a household refrigerator (REF). We found that the rate of abscission, chlorophyll loss, and leaf yellowing differed markedly for the four storages; however, these measures of senescence were linearly related to estimates of cumulative respiration. The ease of measuring leaf abscission, chlorophyll loss, and leaf yellowing permits data collection even with minimal resources. We propose that amaranth would make an effective model plant for comparing the performance of storages differing dramatically in temperature control. A 10% leaf abscission in amaranth is proposed as a target for comparing storages.

New theoretical framework for temperature-effect integration into asphalt concrete pavement life prediction with respect to Australian pavement conditions

The aim of this study is to introduce a new theoretical framework for incorporating the effects of temperature fluctuations into current pavement design approaches by using the cumulative damage concept. Until now, the effective temperature (Teff ) concept, which can integrate the effects of seasonal or monthly temperature fluctuations within a given annual temperature into pavement design, has been utilised, in conjunction with the dynamic modulus (|E*) master curve to determine the representative modulus for an asphalt layer in pavement design. The effective temperature concept is then used to aid the prediction of an asphalt concrete pavement’s service life by assuming that the effective temperature is constant throughout a pavement design period (approximately 20–40 years). However, this assumption is not particularly valid in some countries such as Australia, where the effect of climate change can cause significant fluctuations in temperature during a given pavement design period. In this newly proposed framework, the current effective temperature concept is modified to obtain a so-called optimum effective temperature (TOPT ). From this, the effect of temperature fluctuations during a given design period can be taken into account by using statistically based methods. First, a pavement design scenario was established to demonstrate the new concept. Historical climate data from four study areas in Western Australia was taken and a 10 mm dense graded asphalt mix was used as the basis for pavement design inputs with local material properties and traffic data. Results indicated that optimum pavement design sections, determined according to the new framework considering temperature fluctuations, provided thinner and thicker pavement sections with the cumulative damages (D value) closer to 1 than those of the traditional design approach. The study outcome would result in a more reliable pavement life prediction, leading to saving in construction and maintenance costs.

Seasonal Temperature Fluctuations Differently Affect the Immune and Biochemical Parameters of Diploid and Triploid Oncorhynchus mykiss Cage-Cultured in Temperate Latitudes

In the coming decades, and despite advances in the selection of resistant strains and the production of triploid organisms, the temperature could seriously affect salmonid aquaculture. Lower environmental tolerance has been hinted at for triploids, but the physiological mechanisms leading to such differences, and whether they are translated to the individual level, are poorly understood. This study aimed to evaluate the effects of seasonal variations on the humoral and immune status in the blood (peripheral blood leukocytes) and plasma (antiprotease, lysozyme and peroxidase activities), the oxidative stress (catalase, glutathione-S-transferase, total glutathione and lipid peroxidation) balance in the liver, and the energy budget (sugars, lipids, proteins and energy production) in the liver and muscle of diploid and triploid Oncorhynchus mykiss. Leukocytes’ numbers changed with the water temperature and differed between fish ploidies. Peroxidase activity was increased in the summer, but lysozyme and antiprotease activities were increased in the winter. Concomitantly, antioxidant defenses were significantly altered seasonally, increasing oxidative damage at higher temperatures. Moreover, warmer waters induced a reduction in the energy production measured in the liver. Differences in feed efficiency, which have been previously reported, were confirmed by the low lipid and protein contents of the muscle of the triploids. In sum, the inherent trade-offs to deal with the seasonal changes culminated in the higher growth observed for diploid fish.

Probabilistic effectiveness of visco-elastic dampers considering earthquake excitation uncertainty and ambient temperature fluctuation

The mechanical property of the visco-elastic damper (VED) is dependent on the loading frequency and the ambient temperature. Due to the frequency-dependency, the effectiveness of VED varies as the earthquake excitation alters. However, such an excitation-sensitivity is usually ignored in the design and evaluation of VED. To rationally quantify the VED effectiveness considering the excitation uncertainty, a probabilistic analysis scheme is proposed. In the scheme, multiple response history analyses (RHA) are conducted to reveal the probabilistic properties of the VED effectiveness. The required number of RHA is studied based on three earthquake databases and three VED-structure models with different natural periods. It is shown that at least 30 RHA analyses are needed to get a good result. Due to the temperature-dependency of VED, the probabilistic results are notably influenced by the ambient temperature. Unfortunately, by far, there is no approach to account for the effect of temperature fluctuation on the probabilistic effectiveness of VED. To address this problem, the Fourier series are adopted to model the building thermal environment. By doing so, the seasonal fluctuation of temperature is well incorporated, and the probabilistic property of the working temperature of VED is obtained. Based on the law of total probability, a probabilistic framework for evaluating the effectiveness of VED is established by integrating the effects of excitation uncertainty and temperature fluctuation. The framework consists of two major steps. In step one, the probabilistic effectiveness of VED is computed under a series of pre-defined temperatures. In step two, the probabilistic results under the specific temperatures are integrated over the fluctuating range of the temperature. An example is provided to illustrate the application of the proposed framework. From the example, the temperature fluctuation has little influence on the expectation of the VED effectiveness, but it notably affects the dispersion of the probabilistic effectiveness of VED. In this study, two types of VED (Acrylic and Diene) are considered. The conclusions drawn from the two types of VED are alike.

Bone diagenesis in the loess deposits of Central Europe: the Celtic site of Radovesice in Bohemia

The diagenetic modifications of archaeological bones from the Celtic site of Radovesice (Czech Republic) were described combining histological and instrumental analysis with infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The post-mortem changes in microstructure, mineral and organic fraction of human bones were related to seasonal fluctuations in water saturation and temperature, reflecting the Atlantic influence on the continental climate system of this transitional area of Eastern-Central Europe. The effects of a burial environment characterised by a well-oxygenated soil with good hydraulic conductivity, which evolved from the Quaternary loess deposits of the Bohemian massif, led to a common diagenetic pathway, which comprised micro-fissuring, mineral dissolution and degradation of collagen by microbial activity, followed by secondary calcite deposition under mildly alkaline conditions. Observed intra-site variations reflected changes in the early taphonomic history or in microenvironmental conditions, such as prolonged acidic conditions hindering apatite reprecipitation, as well as secondary calcite crystallisation. Diffuse effects of surface abrasion by sediments and absence of brown staining did not support the hypothesis of extensive use of wooden coffins. New indexes obtained from 31P and 1H NMR, respectively, were employed to describe diagenesis. They were found to correlate with FT-IR indexes, although reflecting distinct structural characteristics of bone which are not accessible to FT-IR.