High Levels Of Solar Radiation Research Articles

A method for estimating direct normal irradiation from GOES geostationary satellite imagery: Validation and application over Northeast Brazil

Abstract The mapping and monitoring of Direct Normal Irradiance (DNI) is most relevant for the proper installation of solar power plants that use concentrating solar systems. This paper presents a satellite-based method for estimating DNI and daily direct normal irradiation (Qn) that uses a minimal set of regional meteorological information and avoids empirical adjustment with ground-based radiometric data. The focus of the validation and application were on the Northeast Brazil region (NEB), which exhibits high solar radiation levels throughout the year. Two basic parameters for satellite-derived DNI estimates are: (i) DNI under clear-sky conditions DNIclear (computed from the REST model) and (ii) cloud cover C (estimated from GOES visible imagery). The first validations were performed by comparison with measurements from three radiometric stations of the SONDA network in the NEB (Petrolina, Natal and Sao Luis) during 2007–2008. Overall, the results confirmed the good performance of the proposed model. DNI daily cycles in conditions of clear and partially cloudy skies were represented satisfactorily, with daily average errors within ±25 W m−2. Good linearity was found between the measured and satellite-estimated Qn, with coefficients of determination (R2) ranging from 0.84 to 0.89. The average values of MBE (Mean Bias Error) and RMSE (Root Mean Square Error) over all sites were −1.7% and 18.7%, respectively. In addition, seasonal and annual average maps of direct normal irradiation were generated over NEB for 2008. It was found that the spatial–temporal variability of Qn is strongly modulated by meteorological systems acting in the region, such as the ITCZ (Intertropical Convergence Zone). The mapped results reveal that the highest value was approximately 22 MJ m−2 on an annual average basis, and higher values occurred in areas of semi-arid climate. The proposed satellite-based model may be applied for providing information of DNI (with a spatial resolution of 4 km), particularly over regions without in situ measurements, and suggests good accuracy for climatic and solar resource studies.

High levels of solar radiation offset impacts of ocean acidification on calcifying and non-calcifying strains of Emiliania huxleyi

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 568:47-58 (2017) - DOI: https://doi.org/10.3354/meps12042 High levels of solar radiation offset impacts of ocean acidification on calcifying and non-calcifying strains of Emiliania huxleyi Peng Jin1, Jiancheng Ding1, Tao Xing1, Ulf Riebesell2, Kunshan Gao1,* 1State Key Laboratory of Marine Environmental Science/College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China 2GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany *Corresponding author: ksgao@xmu.edu.cn ABSTRACT: Coccolithophores, a globally distributed group of marine phytoplankton, showed diverse responses to ocean acidification (OA) and to combinations of OA with other environmental factors. While their growth can be enhanced and calcification be hindered by OA under constant indoor light, fluctuation of solar radiation with ultraviolet irradiances might offset such effects. In this study, when a calcifying and a non-calcifying strain of Emiliania huxleyi were grown at 2 CO2 concentrations (low CO2 [LC]: 395 µatm; high CO2 [HC]: 1000 µatm) under different levels of incident solar radiation in the presence of ultraviolet radiation (UVR), HC and increased levels of solar radiation acted synergistically to enhance the growth in the calcifying strain but not in the non-calcifying strain. HC enhanced the particulate organic carbon (POC) and nitrogen (PON) productions in both strains, and this effect was more obvious at high levels of solar radiation. While HC decreased calcification at low solar radiation levels, it did not cause a significant effect at high levels of solar radiation, implying that a sufficient supply of light energy can offset the impact of OA on the calcifying strain. Our data suggest that increased light exposure, which is predicted to happen with shoaling of the upper mixing layer due to progressive warming, could counteract the impact of OA on coccolithophores distributed within this layer. KEY WORDS: Ocean acidification · Fluctuating light · UV radiation · Coccolithophore · Calcification Full text in pdf format Supplementary material PreviousNextCite this article as: Jin P, Ding J, Xing T, Riebesell U, Gao K (2017) High levels of solar radiation offset impacts of ocean acidification on calcifying and non-calcifying strains of Emiliania huxleyi. Mar Ecol Prog Ser 568:47-58. https://doi.org/10.3354/meps12042 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 568. Online publication date: March 24, 2017 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2017 Inter-Research.

Process Heat Generation Potential from Solar Concentration Technologies in Latin America: The Case of Argentina

This paper evaluates the potential of solar concentration technologies—compound parabolic collector (CPC), linear Fresnel collector (LFC) and parabolic trough collector (PTC)—as an alternative to conventional sources of energy for industrial processes in Latin America, where high levels of solar radiation and isolated areas without energy supply exist. The analysis is addressed from energy, economic and environmental perspective. A specific application for Argentina in which fourteen locations are analyzed is considered. Results show that solar concentration technologies can be an economically and environmentally viable alternative. Levelized cost of energy (LCOE) ranges between 2.5 and 16.9 c€/kWh/m2 and greenhouse gas (GHG) emissions avoided range between 33 and 348 kgCO2/(m2·year). CPC technology stands out as the most recommendable technology when the working fluid temperature ranges from 373 K to 423 K. As the working fluid temperature increases the differences between the LCOE values of the CPC and LFC technologies decrease. When 523 K is reached LFC technology is the one which presents the lowest LCOE values for all analyzed sites, while the LCOE values of PTC technology are close to CPC technology values. Results show that solar concentration technologies have reached economic and environmental competitiveness levels under certain scenarios, mainly linked to solar resource available, thermal level requirements and solar technology cost.

Photoreactivity of riverine and phytoplanktonic dissolved organic matter and its effects on the dynamics of a bacterial community from the coastal Mediterranean Sea

High solar radiation levels measured in the Mediterranean basin can result in photo-oxidation of dissolved organic matter (DOM) at the sea surface. The objective of the present study was to determine the effects of solar radiation on two contrasting sources of DOM (diatom-derived DOM and riverine DOM) and to evaluate its effect on the growth and the composition of a bacterial community from the Mediterranean Sea. DOM was sequentially exposed to artificial solar radiation or kept in the dark and then added to microcosms containing coastal seawater. For both sources of DOM, light exposure induced photo-alterations by decreasing absorbance and fluorescence of colored dissolved organic matter. However, resulting effects on bacteria were contrasted. Photo-alteration of phytoplankton-derived DOM resulted in a lower bacterial growth during the three first days, without modifying the total dissolved organic carbon consumption. Moreover, after 3days of incubation, the bacterial diversity as determined by 16S rRNA gene pyrosequencing, revealed that DOM phototransformation led to a higher relative abundance of Alphaproteobacteria and a lower relative abundance of Gammaproteobacteria. A limited number of operational taxonomic units (OTUs) (n=44) explained 80% of the diversity changes between dark and the light treatments, with an equal number of positively and negatively affected OTUs. In contrast, the photobleaching measured on riverine DOM after sunlight exposure had no effect on both bacterial carbon cycling and composition during a 7-days biodegradation experiment. Our results demonstrate that the effects of solar radiation on DOM greatly differ according to the initial composition of DOM and that changes in bacterial composition, when occurred, showed diverse responses inside a same class of bacteria, underlying the necessity to use a sufficiently resolutive approach to describe them. A better understanding of the interactive effects of the biological degradation and the photoinduced degradation of DOM are required in the context of the global change affecting Mediterranean Sea.

Selecting suitable sites for mountain ginseng (Panax ginseng) cultivation by using geographically weighted logistic regression

With the well-being trends to pursue a healthy life, mountain ginseng (Panax ginseng) is rising as one of the most profitable forest products in South Korea. This study was aimed at evaluating a new methodology for identifying suitable sites for mountain ginseng cultivation in the country. Forest vegetation data were collected from 46 sites and the spatial distribution of all sites was analyzed using GIS data for topographic position, landform, solar radiation, and topographic wetness. The physical and chemical properties of the soil samples, including moisture content, pH, organic matter, total nitrogen, exchangeable cations, available phosphorous, and soil texture, were analyzed. The cultivation suitability at each site was assessed based on the environmental conditions using logistic regression (LR) and geographically weighted logistic regression (GWLR) and the results of both methods were compared. The results show that the areas with northern aspect and higher levels of solar radiation, moisture content, total nitrogen, and sand ratio are more likely to be identified as suitable sites for ginseng cultivation. In contrast to the LR, the spatial modeling with the GWLR results in an increase in the model fitness and indicates that a significant portion of spatial autocorrelation in the data decreases. A higher value of the area under the receiver operating characteristic (ROC) curve presents a better prediction accuracy of site suitability by the GWLR. The geographically weighted coefficient estimates of the model are non-stationary, and reveal that different site suitability is associated with the geographical location of the forest stands. The GWLR increases the accuracy of selecting suitable sites by considering the geographical variations in the characteristics of the cultivation sites.

Bioaccumulation of ultraviolet sunscreen compounds (mycosporine-like amino acids) by the heterotrophic freshwater ciliate Bursaridium living in alpine lakes

Ciliates in shallow alpine lakes are exposed to high levels of incident solar ultraviolet radiation (UVR). We observed the presence of specific sunscreen compounds, the mycosporine-like amino acids (MAAs), in several populations of Bursaridium, a relatively large ciliate species found in such lakes. The populations from 3 highly UV transparent lakes revealed the presence of 7 MAAs (MG, SH, PR, PI, AS, US, and PE) in total concentrations of 3.6–52.4 10−5 μg μg−1 dry weight (DW) per individual, whereas in one glacially turbid and less UV transparent lake, no MAAs were detected in the Bursaridium population. The MAAs in the ciliates generally reflected the composition and relative amounts of the lakes’ seston MAAs, assuming that the ciliates fed on MAA-rich plankton. We experimentally found that naturally acquired MAAs prevented ciliate mortality under simulated UVR and photosynthetically active radiation (PAR) conditions. We further tested the dietary regulation of the MAAs-content in the ciliates under artificial UVR and PAR exposure and found an increase in MAAs concentrations in all treatments. Our assumption was that several stress factors other than irradiation were involved in the synthesis or up-regulation of MAAs.

INTAKE OF ORAL PHOTOPROTECTORS BY POSTMEN IN PORTO ALEGRE

Introduction: Postmen are daily exposed to high levels of solar radiation, and lack of protection can result in many health damages. The present study aimed to identify cutaneous phototypes and evaluate the intake of oral photoprotectors by postmen. Methods: Cross-sectional study, carried out from August 2011 to December 2012 in the city of Porto Alegre, state of Rio Grande do Sul, Brazil. Socioeconomic and behavioral data regarding daily solar exposure were collected through a questionnaire. To evaluate the intake of beta-carotene, lycopene and omega-3, two 24-hour dietary recalls were applied. Cutaneous phototypes were assessed by Fitzpatrick’s classification. Results: A total of 181 postmen were analyzed, whose mean age was 40.2±11.4 years old, and 140 (77.3%) were male. The cutaneous phototypes II, III and IV were the most prevalent (n=138), totaling 76.3% of the sample. The median for the oral photoprotectors intake was 1.16 mg (0.46 – 2.29) of beta-carotene, 3.60 mg (1.01 – 6.31) of lycopene and 0.95 g (0.61 – 1.45) of n-3 fatty acids, all values significantly lower than the minimal doses to obtain photoprotective effect (p<0.001). The individuals in the group of phototypes V and VI showed lower adherence to the use of sunscreen and lower intake of beta-carotene, comparing to the other groups. Conclusions: The intake of oral photoprotectors is low in this population. Future studies may evaluate the real effect of oral photoprotectors, so that preventive measures using this approach can be included in photoprotection education actions for outdoor workers. Keywords: Diet; food and nutrition; skin aging; skin neoplasms; occupational health

Bacterial Active Community Cycling in Response to Solar Radiation and Their Influence on Nutrient Changes in a High-Altitude Wetland.

Microbial communities inhabiting high-altitude spring ecosystems are subjected to extreme changes in solar irradiance and temperature throughout the diel cycle. Here, using 16S rRNA gene tag pyrosequencing (cDNA) we determined the composition of actively transcribing bacteria from spring waters experimentally exposed through the day (morning, noon, and afternoon) to variable levels of solar radiation and light quality, and evaluated their influence on nutrient recycling. Solar irradiance, temperature, and changes in nutrient dynamics were associated with changes in the active bacterial community structure, predominantly by Cyanobacteria, Verrucomicrobia, Proteobacteria, and 35 other Phyla, including the recently described Candidate Phyla Radiation (e.g., Parcubacteria, Gracilibacteria, OP3, TM6, SR1). Diversity increased at noon, when the highest irradiances were measured (3.3–3.9 H′, 1125 W m-2) compared to morning and afternoon (0.6–2.8 H′). This shift was associated with a decrease in the contribution to pyrolibraries by Cyanobacteria and an increase of Proteobacteria and other initially low frequently and rare bacteria phyla (< 0.5%) in the pyrolibraries. A potential increase in the activity of Cyanobacteria and other phototrophic groups, e.g., Rhodobacterales, was observed and associated with UVR, suggesting the presence of photo-activated repair mechanisms to resist high levels of solar radiation. In addition, the percentage contribution of cyanobacterial sequences in the afternoon was similar to those recorded in the morning. The shifts in the contribution by Cyanobacteria also influenced the rate of change in nitrate, nitrite, and phosphate, highlighted by a high level of nitrate accumulation during hours of high radiation and temperature associated with nitrifying bacteria activity. We did not detect ammonia or nitrite oxidizing bacteria in situ, but both functional groups (Nitrosomona and Nitrospira) appeared mainly in pyrolibraries generated from dark incubations. In total, our results reveal that both the structure and the diversity of the active bacteria community was extremely dynamic through the day, and showed marked shifts in composition that influenced nutrient recycling, highlighting how abiotic variation affects potential ecosystem functioning.

The role of coccoliths in protecting &amp;lt;i&amp;gt;Emiliania huxleyi&amp;lt;/i&amp;gt; against stressful light and UV radiation

Abstract. Coccolithophores are a group of phytoplankton species which cover themselves with small scales (coccoliths) made of calcium carbonate (CaCO3). The reason why coccolithophores form these calcite platelets has been a matter of debate for decades but has remained elusive so far. One hypothesis is that they play a role in light or UV protection, especially in surface dwelling species like Emiliania huxleyi, which can tolerate exceptionally high levels of solar radiation. In this study, we tested this hypothesis by culturing a calcified and a naked strain under different light conditions with and without UV radiation. The coccoliths of E. huxleyi reduced the transmission of visible radiation (400–700 nm) by 7.5 %, that of UV-A (315–400 nm) by 14.1 % and that of UV-B (280–315 nm) by 18.4 %. Growth rates of the calcified strain (PML B92/11) were about 2 times higher than those of the naked strain (CCMP 2090) under indoor constant light levels in the absence of UV radiation. When exposed to outdoor conditions (fluctuating sunlight with UV radiation), growth rates of calcified cells were almost 3.5 times higher compared to naked cells. Furthermore, the relative electron transport rate was 114 % higher and non-photochemical quenching (NPQ) was 281 % higher in the calcified compared to the naked strain, implying higher energy transfer associated with higher NPQ in the presence of calcification. When exposed to natural solar radiation including UV radiation, the maximal quantum yield of photosystem II was only slightly reduced in the calcified strain but strongly reduced in the naked strain. Our results reveal an important role of coccoliths in mitigating light and UV stress in E. huxleyi.

Review and validation of Solar Thermal Electricity potential methodologies

With the strong dependence of national economies on energy, interest in solar energy potential assessments is increasing in countries with high solar radiation levels. This article reviews four methodologies proposed in the literature by four different organizations (IDAE, Greenpeace, NREL, and DLR) and proposes a new one (LRS) for assessing the potential of Solar Thermal Electricity (STE) generation in a given country. Derived from these five methodologies, nine cases are studied (IDAE, GP2, NREL1, NREL3, DLR2, DLR2′, LRS1, LRS2, and LRS3). In this study, we followed a two-step STE potential assessment procedure. In the first step, suitable areas for locating STE plants in the country are identified. In the second step, STE plants are assumed to be built and operated in the suitable areas selected in the first step, and the annual electricity generated by these hypothetical plants is estimated.To compare the assessed methodologies, all cases have been applied to the same test country: Spain. Because a relatively large number of commercial STE plants are in operation in Spain, the location of these commercial plants was used to define a simple but effective validation test. A validation process is proposed for the IN-OUT decision based on the buffers containing each existing STE plant. Inside each buffer, a mix of suitable and unsuitable pixels is often included. Thus, the process starts with the decision whether a plant could be considered “IN” the suitable area or not. After the evaluation of the percentage of pixels considered as suitable inside the buffer, and comparing with only the power block pixel location, the second option was selected since it provides good results and simplifies any further treatment. The validation process also considers a minimum of near 90% of the STE plants “IN” suitable areas in order to consider a specific case valid. This means that if a case leaves out more than 10% of the real STE plants, it was considered far from reality and rejected. Cases IDAE, NREL3, DLR2, and the new LRS3 have been validated using the described validation procedure and the last three have very close results with similar levels; this is an important outcome that aims to compare potential assessments performed in different countries by different institutions.

Impact of Solar UV-B Radiation in the Culture of Pacific White Shrimp, Litopenaeus vannamei, Saudi Arabia

Middle East and North African (MENA) region are known for high levels of solar UV radiation. A study was conducted to assess the effect of UV radiation on phytoplankton chlorophyll, β-carotene and growth of pacific white shrimp, Litopenaeus vannamei in HDPE liner culture ponds for 98 days. The experiment is based on control ponds (direct sunlight) and treatment ponds (Green house) using intensive shrimp culture method. Shrimp juveniles (SPF) at the rate of 100/m2 were stocked in each pond and fed with a standard fishmeal based supplementary pellet feed having 35% protein in diet. Physico-chemical parameters of pond water, UV-B radiation, Chlorophyll-a, shrimp growth and β-carotene in meat were monitored during the study period. Significant reduction (p&lt;0.01) in UV-B radiation was found in treatment ponds in comparison with control ponds at an average reduction of 23.2% for surface water due to filtration. Chlorophyll-a in phytoplankton and β- carotene in shrimp were found to be increased in treatment ponds due to low UV-B radiation. However, shrimp growth was not affected significantly (P&gt;0.01) by UV-B radiation in culture ponds.

Multi-effect desalination plant combined with thermal compressor driven by steam generated by solar energy

This paper investigates the annual performance of multi-effect desalination plant combined with a thermo-compressor MED–TC driven by a solar steam generation plant. The desalination model is coupled with solar steam generation plant model to supply the necessary thermal energy to drive the desalination plant. The developed model determines the fresh water production rate and the specific energy consumption. The desalination plant is located in Aqaba, Jordan which is located in a coastal region that receives high levels of solar radiation. Simulations of the system (desalination plant + steam generation plant) are carried out under different operating and geometrical conditions to investigate the plant performance. The desalination plant is sized to produce 50,000m3/day of fresh water continuously to meet the expected commercial and tourism growth. Results show that with collector area equal to 1,080,000m2 and storage size of 75l per square meter of solar collector, the solar energy is capable of covering up to 68% of the total thermal energy required using storage capacity by the desalination plant with annual solar field efficiency of about 55%. The solar field oriented along a north–south axis presents the best performance and the solar fraction does not increase significantly as the pressure of the saturated steam generated varies.

Calculations of automatic chamber flux measurements of methane and carbon dioxide using short time series of concentrations

Abstract. The closed chamber technique is widely used to measure the exchange of methane (CH4) and carbon dioxide (CO2) from terrestrial ecosystems. There is, however, large uncertainty about which model should be used to calculate the gas flux from the measured gas concentrations. Due to experimental uncertainties the simple linear regression model (first-order polynomial) is often applied, even though theoretical considerations of the technique suggest the application of other, curvilinear models. High-resolution automatic chamber systems which sample gas concentrations several hundred times per flux measurement make it possible to resolve the curvilinear behavior and study the information imposed by the natural variability of the temporal concentration changes. We used more than 50 000 such flux measurements of CH4 and CO2 from five field sites located in peat-forming wetlands ranging from 56 to 78° N to quantify the typical differences between flux estimates of different models. In addition, we aimed to assess the curvilinearity of the concentration time series and test the general applicability of curvilinear models. Despite significant episodic differences between the calculated flux estimates, the overall differences are generally found to be smaller than the local flux variability on the plot scale. The curvilinear behavior of the gas concentrations within the chamber is strongly influenced by wind-driven chamber leakage, and less so by changing gas concentration gradients in the soil during chamber closure. Such physical processes affect both gas species equally, which makes it possible to isolate biochemical processes affecting the gases differently, such as photosynthesis limitation by chamber headspace CO2 concentrations under high levels of incoming solar radiation. We assess the possibility to exploit this effect for a partitioning of the net CO2 flux into photosynthesis and ecosystem respiration as an example of how high-resolution automatic chamber measurements could be used for purposes beyond the estimation of the net gas flux. This shows that while linear and curvilinear calculation schemes can provide similar net fluxes, only curvilinear models open additional possibilities for high-resolution automatic chamber measurements.

Sunscreen Increasingly Overshadows Alternative Sun-Protection Strategies.

The present study assessed perceptions of effective sun-protection strategies among the general public and whether these perceptions have changed in recent years. During five summers from 2007/2008 to 2011/2012, 4217 adolescents and adults living in a region with very high levels of solar UV radiation participated in annual, cross-sectional telephone surveys. Respondents' perceptions of the most effective sun-protection strategy were measured with a single open-ended question. In all survey years, sunscreen was the by far most frequently nominated sun-protection strategy, with an average mention rate of 71.0%. The tendency to nominate sunscreen increased significantly over the 5-year study period and on average, was more common among adolescents compared to adults (81.6 vs 60.0%) and females compared to males (73.6 vs 68.3%). Despite respondents' increasing tendency to nominate sunscreen as the most effective sun-protection strategy, health experts have voiced concerns about flawed application practices. Current sun-protection hierarchies indicate that protective clothing and shade are better options.

Antagonistic and synergistic responses to solar ultraviolet radiation and increased temperature of phytoplankton from cenotes (sink holes) of the Yucatán Peninsula, México

Cenotes (sink holes) are karstic formations characteristic of the Yucatán Peninsula and are the main source of fresh water in the region. Because of their tropical location, they receive high levels of solar radiation and are exposed to high temperatures. However, the effect of these global-change-related variables on phytoplankton in cenotes is unknown. We carried out experiments with phytoplankton communities collected from 2 cenotes differing in their penetration of solar radiation (Leona Vicario [LV]: turbid, Las Mojarras [LM]: clear) to assess the combined effect of solar ultraviolet radiation (UVR; 280–400 nm) and increased temperature on their photosystem (PS) II photochemistry. We exposed samples in microcosms to solar radiation (with and without UVR) and 2 temperatures (ambient = 25°C and increased by 3°C) and analyzed photochemical performance over daily cycles. A significant antagonistic interaction between UVR and temperature in LV caused a combined inhibition of the effective photochemical quantum yield (ΦPSII) that was smaller (63%) than the sum of the 2 individual effects of UVR and temperature (116%). In contrast, a significant synergistic interaction between UVR and temperature in LM caused the combined inhibition of ΦPSII (172%) to be higher than the sum of the individual effects of the 2 variables (134%). Differences in the size distribution and taxonomic composition of the phytoplankton communities, with smaller cells in LV than in LM, seem to account for much of the variability in responses to UVR and increased temperature between the 2 communities. Our results suggest that phytoplankton communities from clear cenotes will be more affected by the combined effects of solar UVR and increased temperature that those from turbid cenotes.

Collection and Storage of Solar Gains Incident on the Floor in a House During the Heating Season

Large amounts of south facing windows can help reduce heating demand in the winter and shoulder seasons by allowing high levels of solar radiation to enter the building. One problem that may arise from large areas of south facing glazing is overheating of the adjacent rooms, even during winter in a cold climate.Cooling of the floors may provide a means to prevent overheating in such a situation. Cooling a floor prevents solar gains absorbed by the floor from being transferred to the space by convection or infrared radiation. This cooling can be achieved with the use of water pipes in the floor. The heat removed can be upgraded to a higher temperature with a heat pump, and then may be stored in a thermal storage tank for space heating and domestic hot water heating.This paper shows preliminary simulation results of such a system for a house in Ottawa, Canada. The house contains a much larger south facing window area than is typical. In periods of overheating, the solar gains are absorbed by the floor cover and collected by the cold pipes in the floor. The heat is upgraded by a heat pump and stored in a hot storage tank.Preliminary modelling results show that, with the use of a large thermal storage tank (2 m3), space heatingand domestic hot water demand with this type of system may be reduced by as much as 24%, when compared with a more conventional house.

Photosynthetic Performance of the Red Alga Pyropia haitanensis During Emersion, With Special Reference to Effects of Solar UV Radiation, Dehydration and Elevated CO2 Concentration

Macroalgae distributed in intertidal zones experience a series of environmental changes, such as periodical desiccation associated with tidal cycles, increasing CO2 concentration and solar UVB (280-315 nm) irradiance in the context of climate change. We investigated how the economic red macroalga, Pyropia haitanensis, perform its photosynthesis under elevated atmospheric CO2 concentration and in the presence of solar UV radiation (280-400 nm) during emersion. Our results showed that the elevated CO2 (800 ppmv) significantly increased the photosynthetic carbon fixation rate of P. haitanensis by about 100% when the alga was dehydrated. Solar UV radiation had insignificant effects on the net photosynthesis without desiccation stress and under low levels of sunlight, but significantly inhibited it with increased levels of desiccation and sunlight intensity, to the highest extent at the highest levels of water loss and solar radiation. Presence of UV radiation and the elevated CO2 acted synergistically to cause higher inhibition of the photosynthetic carbon fixation, which exacerbated at higher levels of desiccation and sunlight. While P. haitanensis can benefit from increasing atmospheric CO2 concentration during emersion under low and moderate levels of solar radiation, combined effects of elevated CO2 and UV radiation acted synergistically to reduce its photosynthesis under high solar radiation levels during noon periods.

Comparative analysis of technical and economic parameters of different schemes of the electric power supply of autonomous desalination plants

This article reviews possible schemes of the power supply of an autonomous reverse osmosis desalination plant that uses a photoelectric converter as primary energy sources. Using the climate data of several regions that have a shortage of fresh water for drinking and technical purposes, a technical and economic evaluation of the use of solar energy for obtaining fresh water in regions with high levels of solar radiation was performed. The prospects of the partial or complete substitution of diesel fuel by energy derived from photoelectric converters in such systems for regions with a high level of insolation and cost of diesel fuel are shown.

Sun Protection and Skin Examination Practices in a Setting of High Ambient Solar Radiation: A Population-Based Cohort Study.

Primary prevention and early detection are integral strategies to reduce the burden of skin cancer. To describe the prevalence of sun protection and skin examination practices in a population exposed to high levels of ambient solar radiation and to identify associated factors. Cross-sectional analyses of baseline data from a prospective cohort of 40,172 adults aged 40 through 69 years from Queensland, Australia, recruited in 2011. We obtained data on all melanoma diagnoses through 2009 via record linkage with the Queensland Cancer Registry (notifications have been mandatory since 1982). We calculated prevalence proportion ratios to compare prevalence of sun protection and skin examination practices in 3 separate groups: those with a history of melanoma (group 1), those with a self-reported history of treated actinic lesions (group 2), and those without either (group 3). We used multivariate generalized linear models to identify factors associated with each practice. Participants with a previously confirmed melanoma (group 1; n = 1433) and/or treated actinic lesions (group 2; n = 24,006) were more likely than those without (group 3; n = 14,733) to report sun protection practices, including regular use of sunscreen (53.3%, 45.1%, and 38.1%, respectively) and wearing hats (74.7%, 68.2%, and 58.2%, respectively). They were also more likely to have had a whole-body skin examination by a physician in the past 3 years (93.7%, 83.4%, and 52.1%, respectively). Within all 3 groups, the strongest association with sun protection practices was with sun-sensitive skin type. Within group 3 (no history of treated skin lesions), the strongest factor associated with clinical skin examinations was self-reported nevus density at 21 years of age, whereas a family history of melanoma was a significant factor in groups 2 and 3. In this large sample exposed to high levels of ambient solar radiation, sun protection and skin examination practices were most frequent among those with a history of treated skin lesions or sun-sensitive skin types.

Lack of Physiological Depth Patterns in Conspecifics of Endemic Antarctic Brown Algae: A Trade-Off between UV Stress Tolerance and Shade Adaptation?

A striking characteristic of endemic Antarctic brown algae is their broad vertical distribution. This feature is largely determined by the shade adaptation in order to cope with the seasonal variation in light availability. However, during spring-summer months, when light penetrates deep in the water column these organisms have to withstand high levels of solar radiation, including UV. In the present study we examine the light use characteristics in parallel to a potential for UV tolerance (measured as content of phenolic compounds, antioxidant activity and maximum quantum yield of fluorescence) in conspecific populations of four Antarctic brown algae (Ascoseira mirabilis, Desmarestia menziesii, D. anceps and Himantothallus grandifolius) distributed over a depth gradient between 5 and 30 m. The main results indicated that a) photosynthetic efficiency was uniform along the depth gradient in all the studied species, and b) short-term (6 h) exposure to UV radiation revealed a high tolerance measured as chlorophyll fluorescence, phlorotannin content and antioxidant capacity. Multivariate analysis of similarity indicated that light requirements for photosynthesis, soluble phlorotannins and antioxidant capacity are the variables determining the responses along the depth gradient in all the studied species. The suite of physiological responses of algae with a shallower distribution (A. mirabilis and D. menziesii) differed from those with deeper vertical range (D. anceps and H. grandifolius). These patterns are consistent with the underwater light penetration that defines two zones: 0–15 m, with influence of UV radiation (1% of UV-B and UV-A at 9 m and 15 m respectively) and a zone below 15 m marked by PAR incidence (1% up to 30 m). These results support the prediction that algae show a UV stress tolerance capacity along a broad depth range according to their marked shade adaptation. The high contents of phlorotannins and antioxidant potential appear to be strongly responsible for the lack of clear depth patterns in light demand characteristics and UV tolerance.