Positive Effect Of Temperature Research Articles

Grey correlation analysis and path analysis between isoflavones content in Astragali Radix and climate factors

In this study, HPLC was used to determine the content of the four isoflavones of Astragalus membranceus var. mongholicus from different regions(calycosin-7-glucoside, ononin, calycosin and formononetin), and gray correlation analysis and path analysis were used to explore the influence of climate factors on the content of isoflavone components in A. membranceus var. mongholicus. The results showed that there were significant differences in the content of the four isoflavones in different areas(P<0.05); grey correlation analysis showed that the highest temperature in July, the lowest temperature in January and the daily average temperature had a greater impact on the content of flavonoid glycosides, meanwhile precipitation and relative humidity were the more important factors for the accumulation of flavonoid aglycones. According to the general analysis, the direct positive effects of the lowest temperature in January and altitude on the contents of four isoflavones in A. membranceus var. mongholicus were significant. High altitude and extreme temperature conditions might be more adverse to the formation and accumulation of isoflavone components. Therefore, the religions of A. membranceus var. mongholicus with high contents of isoflavones should be chosen the low altitude region with higher minimum temperature in January. This study provides a reference basis for the quality evaluation of A. membranceus var. mongholicus, and basic data for the selection of suitable habitat, construction of planting standards and directional cultivation of medicinal materials in A. membranceus var. mongholicus.

Short-term effects of meteorological factors, air pollution, and sunspot on childhood hand, foot, and mouth disease in Tianjin, China: a new time series regression, 2014-2018.

This study is aimed at defining the relationship between a set of environmental factors and childhood HFMD and then at estimating the related effect. The 16 environmental factors included meteorological, air pollution, and sunspot. A traditional TSR modified by using susceptible-infectious-recovery models and distribution lag nonlinear model was applied to estimate the short-term effects of daily environmental factors on children HFMD occurrence in 2014–2018 with adjustment of potential confounding factors. A total of 70,027 children aged 0–15 years with HFMD were enrolled. No significant effect was observed for daily sunspot numbers and average visibility. We found positive effects of the ambient average temperature, with an approximately m-shaped curve of the overall cumulative relationship, peaking at 25.6 °C with a relative risk (RR) of 1.45 (95% confidence intervals 1.21–1.73). The largest RR value of hot effect was achieved on the current day and then decreased by 2 days (total group, male group, and scatter group) or 1 day (female group and nursery group), and the effect lasted about 6 to 8 days from the lag 4 or lag 6 day. A greater association of temperature with HFMD for the female group and the scattered group was observed. This study suggests that ambient average temperature might be a risk factor for children HFMD in Tianjin. Further studies are warranted to confirm these findings.

Dendroclimatic study of a mixed spruce-fir-beech forest in the Czech Republic

European forests are undergoing an important transition due to the current climate change, as monocultures are being gradually replaced by mixed forests. Understanding tree growth in mixed forests under a changing climate is challenging because of tree species’ adaptation and long-term forest planning. In this study, we evaluate the long-term behaviour of Norway spruce (Picea abies), silver fir (Abies alba) and European beech (Fagus sylvatica) from a low montane range at the Czech-Austrian border. Species-specific tree-ring width chronologies have revealed significantly decreasing growth trends since the 2000s. Temporally unstable climate–growth relationships showed an increasing negative effect of current growing season drought on spruce growth and a positive effect of dormant season temperature on fir and beech growth. Our results suggest that though species’ response to climate change differs in the mixed forest, growth reduction in the last years has been proved for all species, likely due to frequent climate extremes.

Positive temperature effects on the initiation and intensity of cannibalistic behaviour of larval pike, Esox lucius L. Is cannibalism reflected in otolith fluctuating asymmetry?

Cannibalism can be a significant factor limiting the survival of pike, Esox lucius, early life stages in both natural and aquaculture conditions. In the present research, type I cannibalism was studied in pike larvae (size range: 9–32.5 mm standard length, SL) in controlled conditions for 45 days post-hatching (dph). For this purpose, the occurrence of cannibalistic pairs, i.e. prey caught by a cannibal inside the cannibal’s mouth, was monitored for 15 min periods by two observers six times daily. Cannibalism was not observed in fish that still had yolk-sacs, but it did occur as soon as the yolk-sac was absorbed on 5 dph at a body size of 13 mm at 22 °C and 10 dph at a body size of 13.4 mm at 15 °C. The ratio of prey to predator size was on average 87%, but the smallest observed size difference was only 1.3%. The intensity of cannibalistic attacks depended on water temperature with more intense cannibalism at 22 °C than at 15 °C, and no cannibalism at 10 °C. Fluctuating asymmetry (FA) in all three sagittal otolith size parameters (area, width, and length) was higher in prey than in cannibals, the differences were not statistically significant.

Growth Rate, Ration, and Temperature Effects on Otolith Elemental Incorporation

The application and utility of otolith chemistry continues to expand despite an incomplete understanding of the mechanisms that regulate elemental incorporation. An unresolved question is what role individual factors such as growth play in regulating elemental incorporation. Disentangling growth variation from thermal effects is particularly challenging in fishes yet integral to understanding the mechanisms of incorporation and interpreting patterns of variation in the field. Juvenile Pacific cod (Gadus macrocephalus) were maintained in a controlled laboratory setting to evaluate the relative importance of growth rate, ration, and temperature on otolith elemental incorporation. Fish were held at four temperatures (2, 5, 9, 13 C) and fed daily to apparent satiation. An additional treatment included fish that were held at 9 C and fed a reduced ration (1% body mass d-1). Fish were maintained for variable duration (40-147 d), depending on ration and temperature, to ensure adequate otolith growth for analysis. Water samples for chemical analysis were collected to determine elemental partition coefficients (DMe). Overall, mean growth rates ranged from -0.09 to 1.52% d-1. For the 9 C fish, there was a clear ration effect on DMn (2.6X higher at high ration) and DSr (1.5X higher at low ration), a small effect for DMg (1.1X), and no effect for DBa. For high ration fish, there was a positive effect of temperature on DMn and DMg, due solely to differences in the 2 C treatments, and no effect on DSr and DBa. Correlations between growth and DMe within temperature treatments were variable but, for DMn and DSr, the directionality mirrored the ration effect with positive correlations for DMn and negative correlations for DSr. Overall, the observed ration effects were greater than any growth rate effect, indicating that the effect of ration accounts for more than growth variation.

THE ECONOMIC IMPACTS OF GLOBAL WARMING ON CHINESE CITIES

There is a substantial concern for the economic impacts of global warming. This study identifies the effects of seasonal temperatures on total economic output in the cities of China, and then projects the changes in local economic performance under future climate and development scenarios. The results suggest that there are significant negative effects of warm seasonal temperature but positive effects of cold seasonal temperature on economic growth. These different effects increase as more lags of temperature are included. By 2090, the cities may have the average reduction of 44% in GDP per capita under RCP8.5, but some of them in Northeast China are predicted to get positive impacts under RCP2.6. The difference in the estimated aggregate impacts under the two RCPs could be as much as 24%. The poor cities are likely to have higher economic damages, which amplifies the economic inequality. Finally, the ranges of economic impacts projected by different climate models are presented.

Climate synchronises shrub growth across a high‐arctic archipelago: contrasting implications of summer and winter warming

Climate change is most pronounced at high latitudes, where plant and animal populations are often strongly influenced by environmental fluctuations related to climate and weather. Environmental conditions can co‐fluctuate over large distances and thereby synchronise primary production in space. However, large‐scale studies of such spatiotemporal patterns remain rare in the Arctic, where short time‐series and poor spatial replication have characterised the data available on both biotic and abiotic parameters. Here, we use dendrochronological tools to measure ring growth of a dominant dwarf shrub, the polar willow Salix polaris, previously found to reliably trace community‐level vascular plant biomass production. We investigated climate drivers of vegetation growth and their role in the synchronisation of primary production across the rapidly warming archipelago of Svalbard (n = 8 sites, composed of 17 sub‐sites, 0.06–293 km apart). We found contrasting effects of summer versus winter weather on ring growth and its spatial synchrony. Although an overall positive effect of summer temperature caused spatially synchronous growth, negative impacts of winter rain‐on‐snow events occurred only locally, potentially counteracting such synchrony. However, the anticipated increase in both summer temperature and spatial extent of rain‐on‐snow events, causing basal ice encapsulation of the vegetation, could change the relative importance of seasons for spatiotemporal dynamics of shrub growth. Because these shrub ring growth chronologies reflect annual fluctuations in total vascular plant biomass, fuelling the bottom–up controlled food‐web, these results have large implications for our understanding of how climate change shapes tundra ecosystem productivity in time and space.

Population dynamics and regulation of the Middle Spotted Woodpecker in strictly protected and managed forests in Western Poland

Analysis of ecological time series allows to assess the relative contribution of density-dependent and density-independent factors influencing the regulation of the population of a species. In this study, we investigated whether the annual fluctuation in the population of Middle Spotted Woodpeckers Dendrocoptes medius can be attributed to the direct or delayed density-dependent regulation or to the density-independent factors such as weather conditions during the preceding winter and previous breeding season and/or disturbance in the habitat associated with sanitary felling and salvage logging of trees. This study was conducted in the Czeszewo Forest Reserve, which protects the remnants of semi-natural flood-plain forest, and in the Łówkowiec Forest, which is a managed oak-dominated stand, during 19 seasons (2001–2019). Time series diagnostic revealed that the growth rate of population of Middle Spotted Woodpecker in protected semi-natural riverine forest and in managed oak forest was determined by first-order negative feedback, suggesting an important role of direct density-dependent mortality in the regulation of an equilibrium in population size. The effect of density-dependent process varied between study sites, being lower in riverine forest, where population size has increased distinctly in recent years. In both study areas, we detected strong positive effects of wind chill temperature during the preceding winter on population growth rates. We did not find evidence for the assumption that the increase in population growth rate is affected by weather conditions in the previous breeding season and by the disturbance in the habitat associated with sanitary felling and salvage logging of trees. Our results suggest that Middle Spotted Woodpeckers can benefit from global climate warming by an enhanced rate of winter survival or an increase in the accessibility of food, e.g., insects and other arthropods. The lack of time-lag significant correlations between population fluctuations suggests local habitat conditions, e.g., forest management, can modify inter-annual variability in time series of the Middle Spotted Woodpecker.

Perylene Bisimide and Naphthyl‐Based Molecular Dyads: Hydrogen Bonds Driving Co‐planarization and Anomalous Temperature‐Response Fluorescence

AbstractThe origin of the positive temperature effect in fluorescence emission of a newly designed perylene bisimide (PBI) derivative with two naphthyl units containing ortho‐methoxy group (NM) at its bay positions (PBI‐2NM) was elucidated. A key point is the finding of a weak hydrogen bond (<5.0 kcal mol−1) between the methoxy group of the NM unit and a nearby hydrogen atom of the PBI core. It is the bonding that drives co‐planarization of the different aromatic units, resulting in delocalization of the π‐electrons of the compound as synthesized, inducing fluorescence quenching via intramolecular charge transfer (ICT). With increasing temperature, the co‐planar structure could be distorted in part, resulting in a decreased degree of ICT, and hence leading to enhanced fluorescence emission. The unique positive temperature effect in emission induced by H‐bond‐driven co‐planarization may pave a new avenue in designing functional molecular systems complementary to conventional methods.

Perylene Bisimide and Naphthyl-Based Molecular Dyads: Hydrogen Bonds Driving Co-planarization and Anomalous Temperature-Response Fluorescence.

The origin of the positive temperature effect in fluorescence emission of a newly designed perylene bisimide (PBI) derivative with two naphthyl units containing ortho-methoxy group (NM) at its bay positions (PBI-2NM) was elucidated. A key point is the finding of a weak hydrogen bond (<5.0 kcal mol-1 ) between the methoxy group of the NM unit and a nearby hydrogen atom of the PBI core. It is the bonding that drives co-planarization of the different aromatic units, resulting in delocalization of the π-electrons of the compound as synthesized, inducing fluorescence quenching via intramolecular charge transfer (ICT). With increasing temperature, the co-planar structure could be distorted in part, resulting in a decreased degree of ICT, and hence leading to enhanced fluorescence emission. The unique positive temperature effect in emission induced by H-bond-driven co-planarization may pave a new avenue in designing functional molecular systems complementary to conventional methods.

Warmer mid-day temperatures increase leaf intake by increasing forager speed and success in Atta colombica during the rainy season

Predicting the effects of climatic warming on social insects remains an important challenge. While warming is known to speed many rate processes, the acute effects of temperature on performance under field conditions remain poorly studied. The effects of temperature are usually nonlinear, and tropical animals have been predicted to be particularly likely to be negatively affected by global warming as they may have optimal temperatures that are close to current ambient temperatures. We observed three different A. colombica colonies three times per day (two times during daylight hours and one time at night) during June 2018 in Gamboa, Panama, measuring air temperature, ant traffic, intake of leaves per second, and ant walking speeds. We found that ant walking speed and intake of leaves increased at higher temperatures. Leaves carried per ant also increased with temperature, suggesting that warmer temperatures improve leaf-handling rates, at least over the thermal range studied here. However, there was also an independent effect of time of day, with higher foraging in the morning than the evening, despite similar air temperatures. Consistent with the positive effect of temperature on foraging rates, critical thermal maxima were well above ground temperatures. At least during the rainy season, our data suggest that moderate warming could enhance foraging success and herbivory of leafcutting ants in semi-deciduous moist forests throughout much of the day.

Crop intensification with sustainable practices did not increase N2O emissions

Nitrous oxide (N2O) is the most important greenhouse gas produced by agricultural soils and is a byproduct of microbial nitrification and denitrification processes. The N2O emission rates depend on soil, climatic and management factors. The objectives of this study were i) to evaluate N2O emissions during a barley crop period and its subsequent barley-maize interperiod, under two management systems, and ii) to relate the N2O flux rates with soil mineral N content, waterfilled pore space (WFPS) and soil temperature. These periods are part of three-year crop sequence (barley - maize - soybean) of a long-term experiment under two management systems, ecological intensification (EI) and farmer current practices (FP). For the analyzed period, the EI system included a cover crop after barley and higher N rates, with split application, compared to FP. N2O emissions were monitored weekly using a static chambers method. Simultaneously, the mineral N content (NO3--N and NH4+-N), WFPS and soil temperature at 10 cm depth were determined. The flux of N2O-N ranged from 6 to 61 μg of N2O-N m2 h-1 during the barley crop and between 1.5 and 47 μg of N2O-N m2 h-1 during the barley-maize interperiod, without significant differences between management systems. N2O emissions were controlled by soil temperature and %WFPS according to a multiple regression analysis. NH4+-N and NO3--N soil content did not enter into any model as a regulator of N2O flux. During the barley period there was a significant effect of the WFPS × soil temperature interaction since N2O emissions increased with soil temperature only at WFPS > 40 %. During the barley-maize interperiod, there were significant positive effects of WFPS and temperature on N2O emissions with no significant WFPS x temperature interaction. The cumulative emissions of N2O-N were not different between management systems during the barley crop (IE = 646 and FP=757 g N2O-N ha-1) or during barley-maize interperiod (IE = 816 and FP=754 g N2O-N ha-1). Throughout the study period, the combination of management practices in EI increased barley yield and did not increase N2O emissions with respect to FP, despite higher N rates and the inclusion of cover crop in EI. The intensification of crops does not necessarily increase N2O emissions from agricultural soils as long as the crops are conducted with appropriate management practices.

Effects of temperature and viscosity on miracidial and cercarial movement of Schistosoma mansoni: ramifications for disease transmission

Parasites with complex life cycles can be susceptible to temperature shifts associated with seasonal changes, especially as free-living larvae that depend on a fixed energy reserve to survive outside the host. The life cycle of Schistosoma, a trematode genus containing some species that cause human schistosomiasis, has free-living, aquatic miracidial and cercarial larval stages that swim using cilia or a forked tail, respectively. The small size of these swimmers (150–350 µm) dictates that their propulsion is dominated by viscous forces. Given that viscosity inhibits the swimming ability of small organisms and is inversely correlated with temperature, changes in temperature should affect the ability of free-living larval stages to swim and locate a host. By recording miracidial and cercarial movement of Schistosoma mansoni using a high-speed camera and manipulating temperature and viscosity independently, we assessed the role each factor plays in the swimming mechanics of the parasite. We found a positive effect of temperature and a negative effect of viscosity on miracidial and cercarial speed. Reynolds numbers, which describe the ratio of inertial to viscous forces exerted on an aquatic organism, were <1 across treatments. Q10 values were <2 when comparing viscosity treatments at 20 °C and 30 °C, further supporting the influence of viscosity on miracidial and cercarial speed. Given that both larval stages have limited energy reserves and infection takes considerable energy, successful transmission depends on both speed and lifespan. We coupled our speed data with mortality measurements across temperatures and discovered that the theoretical maximum distance travelled increased with temperature and decreased with viscosity for both larval stages. Thus, our results suggest that S. mansoni transmission is high during warm times of the year, partly due to improved swimming performance of the free-living larval stages, and that increases in temperature variation associated with climate change might further increase transmission.

Long‐term study of the reproductive timing of the Neotropical catfish Iheringichthys labrosus (Lütken, 1874): Influence of temperature and river discharge

AbstractUnravelling the effect of climate variability on species biology has been one of the main goals of ecological studies. Environmental factors such as river discharge and temperature have being proposed as triggers of reproductive cycle in fish. In temperate climates, fish reproduction is affected mainly by temperature, while is influenced by flood pulses in large tropical rivers. We evaluated the influence of temperature and river discharge as triggers of Iheringichthys labrosus’ reproduction. We studied the following reproductive variables: gonadosomatic index (GSI), hepatosomatic index (HSI) and condition factor (K). Females of I. labrosus were examined in a time series of ten years along three sites located in Lower Uruguay River at the beginning (last week of November‐first week of December, spring) and by the end of the reproductive period (middle‐end of April, autumn). Generalised linear models detected a positive effect of mean winter temperature and site on the spring mature female GSI. Site was significant in addition to the interaction between temperature and site. Moreover, the effect of winter temperature was stronger than water discharge in triggering reproductive timing of I. labrosus, contrary to the model proposed for other species in tropical systems. Additionally, a literature review suggested a latitudinal gradient on reproduction, occurring earlier and prolonged with decreasing latitude (and increasing temperature). In this study, we stated the effect of temperature on the life history in a Neotropical fish using a multifaceted approach, particularly important in the current context of global climate warming.

Density‐Dependence Mediates the Effects of Temperature on Growth of Juvenile Blue Catfish in Nonnative Habitats

AbstractThe combined effects of conspecific density and climate warming on the vital rates of invasive fish species have not been well studied, but may be important in predicting how successful they will be in the future. We evaluated the effects of temperature and population density on monthly time series of sizes of age‐0 Blue Catfish Ictalurus furcatus in the James, York, and Rappahannock River subestuaries (defined here as tidally influenced bodies of water that feed into the Chesapeake Bay) from 1996 to 2017, using growing degree‐days (GDDs, °C day) as a measure of thermal time. Our predictive linear mixed‐effects model explained 86% of the variation in the length of age‐0 Blue Catfish. In addition, it indicated a strong positive effect of temperature on the growth rate of age‐0 Blue Catfish, with individual fish biomass during warm years up to 63% higher than during cool years. Growth rate was influenced negatively by the abundance of age‐0 and older fish, resulting in at least fourfold differences in the predicted biomass of Blue Catfish by the end of the first year of life depending on conspecific density. We also observed regional differences in the growth rates of Blue Catfish in the three subestuaries we examined; although growth occurred in all subestuaries, growth was highest for the Rappahannock River population even though this river accumulated the fewest GDDs. Rising water temperatures due to global climate change will likely increase the growth rate of age‐0 Blue Catfish in the Chesapeake Bay region, potentially intensifying the negative impacts of this invasive species on the ecology of Chesapeake Bay. However, individual populations respond differently to warming temperatures, and thus, potential increases in the growth rate of age‐0 Blue Catfish may be partially offset by local conditions that may serve to limit growth.

Modelling the Impact and Effects of Climatic Variability on Electricity Energy Consumption in the Yendi Municipality of Ghana

One of the cherished assets of every economy is electricity since it has proven to be the major source of energy for industrialization. Developing economies like Ghana have suffered the downside of poor management of the already inadequate electrical energy at its disposal. This is as a result of limited research into factors that influences electricity energy consumption, most importantly, the effects of climatic variables on electricity energy consumption. This research work explores the causal connection between climatic variables and electricity energy consumption, and develops a Vector Auto Regression (VAR) model to determine the influence of the climatic variables in forecasting electricity energy consumption in Yendi Municipality in the northern region of Ghana. The climatic factors considered in this work are; Rainfall (Rain), maximum temperature (Tmax), Sunshine (Sun), Wind (wind) and Relative Humidity (RH). The Granger causality tests employed in this work revealed that aside from Relative Humidity, the end energy consumption is affected by the other four climatic factors under consideration. The impulse response was used to ascertain the active interaction among electricity energy consumption and the climatic variables. The impulse response of electricity energy consumption to the climatic variables indicates a maximum positive effect of Temperature and Sunshine on electricity energy consumption in March and September respectively. The VAR model was also used in forecasting future consumption of electricity energy. The results indicate excellent forecasts of electricity energy consumption for the first four months of 2019.

Potential feedback mediated by soil microbiome response to warming in a glacier forefield.

Mountain glaciers are retreating at an unprecedented rate due to global warming. Glacier retreat is widely believed to be driven by the physiochemical characteristics of glacier surfaces; however, the current knowledge of such biological drivers remains limited. An estimated 130Tg of organic carbon (OC) is stored in mountain glaciers globally. As a result of global warming, the accelerated microbial decomposition of OC may further accelerate the melting process of mountain glaciers by heat production with the release of greenhouse gases, such as carbon dioxide (CO2 ) and methane. Here, using short-term aerobic incubation data from the forefield of Urumqi Glacier No. 1, we assessed the potential climate feedback mediated by soil microbiomes at temperatures of 5°C (control), 6.2°C (RCP 2.6), 11°C (RCP 8.5), and 15°C (extreme temperature). We observed enhanced CO2 -C release and heat production under warming conditions, which led to an increase in near-surface (2m) atmospheric temperatures, ranging from 0.9°C to 3.4°C. Warming significantly changed the structures of the RNA-derived (active) and DNA-derived (total) soil microbiomes, and active microbes were more sensitive to increased temperatures than total microbes. Considering the positive effects of temperature and deglaciation age on the CO2 -C release rate, the alterations in the active microbial community structure had a negative impact on the increased CO2 -C release rate. Our results revealed that glacial melting could potentially be significantly accelerated by heat production from increased microbial decomposition of OC. This risk might be true for other high-altitude glaciers under emerging warming, thus improving the predictions of the effects of potential feedback on global warming.

Alternative pathways to diversity across ecologically distinct lizard radiations

AbstractAimLizard assemblages vary greatly in taxonomic, ecological and phenotypic diversity, yet the mechanisms that generate and maintain these patterns at a macroecological scale are not well understood. We aimed to characterize the ecological and environmental drivers of species richness patterns in the context of macroecological theory for 10 independent lizard radiations.LocationGlobal.Time periodPresent day.Major taxaLizards.MethodsWe analysed patterns of species and functional trait diversity in 10 ecologically distinct and widely distributed clades encompassing nearly all known lizard species. Using recently published spatial, phylogenetic, and functional trait datasets, we built spatially explicit structural equation models to ask whether species richness was directly or indirectly related to functional divergence or convergence within communities, and with features of the environment, including measures of productivity, complexity and harshness.ResultsOur results show that high species richness is achieved via different pathways in different lizard clades, with both functionally divergent and convergent assemblages harbouring high diversity in different clades. More generally, we also find common, positive effects of temperature, productivity and topography on species richness within lizard clades.Main conclusionsThermal constraints, topographic complexity and spatial structuring of functional diversity help explain the presence of highly diverse lizard assemblages, suggesting the importance of environmental filters in shaping present‐day diversity and assemblage structure. Our results show how different pathways to high richness in different clades have contributed to the overall global pattern of species richness in reptiles.

Global divergent responses of primary productivity to water, energy, and CO2

The directionality of the response of gross primary productivity (GPP) to climate has been shown to vary across the globe. This effect has been hypothesized to be the result of the interaction between multiple bioclimatic factors, including environmental energy (i.e. temperature and radiation) and water availability. This is due to the tight coupling between water and carbon cycling in plants and the fact that temperature often drives plant water demand. Using GPP data extracted from 188 sites of FLUXNET2015 and observation-driven terrestrial biosphere models (TBMs), we disentangled the confounding effects of temperature, precipitation and carbon dioxide on GPP, and examined their long-term effects on productivity across the globe. Based on the FLUXNET2015 data, we observed a decline in the positive effect of temperature on GPP, while the positive effects of precipitation and CO2 were becoming stronger during 2000–2014. Using data derived from TBMs between 1980 and 2010 we found similar effects globally. The modeled data allowed us to investigate these effects more thoroughly over space and time. In arid regions, the modeled response to precipitation increased since 1950, approximately 30 years earlier than in humid regions. We further observed the negative effects of summer temperature on GPP in arid regions, suggesting greater aridity stress on productivity under global warming. Our results imply that aridity stress, triggered by rising temperatures, has reduced the positive influence of temperature on GPP, while increased precipitation and elevated CO2 may alleviate negative aridity impacts.

Investigation of the Temperature Effect on the Output Parameters of Radioisotope Sources of Electricity Based on Double Energy Conversion of Radiative Decay

When developing long-life radioisotope sources of electricity for various applications (space industry, medicine, nano- and microsystem technology, cryptography, and telecommunications), an important problem lies in determining the temperature range of their reliable operation. The effect of negative and positive temperatures in the range from –60 to +60°C on the output parameters of radioisotope electricity sources based on double energy conversion is studied. It is shown that the open-circuit voltage of a radioisotope source changes four times in the indicated temperature ranges. In this case, the highest power delivered to the load is implemented at a temperature of about 0°C. The effect of temperature on all stages of energy conversion is analyzed. The investigations show that a significant decrease in the open-circuit voltage and the shape of the power-output curve are determined by two mechanisms: a decrease in the luminous intensity of radioluminescent sources of light (the temperature quenching of luminescence) and a decrease in the efficiency of photoconverters. Moreover, in the range of negative temperatures (from –60 to 0°C), the decrease in the efficiency of photoconverters is expressed only slightly, and the main contribution to the change in the output parameters of the sources is introduced by the temperature quenching of luminescence in the source of light. In the range of positive temperatures, both processes have a significant effect on reducing the output voltage and power. The developed radioisotope electrical-power sources based on double conversion can be used in electronic equipment operating at lower temperatures, for example, under Far-North conditions.