Natural Temperature Conditions Research Articles

Accounting of weathering enhancement by mafic mineral spreading for CO 2 storage

The reduction of atmospheric CO 2 is an urgent global issue in the mitigation of global warming. Carbonate acts as a carbon sink in Earth's surface layer, and the weathering of terrestrial silicates and the deposition of oceanic calcium carbonate and organic matter mainly determine atmospheric and oceanic carbon dynamics on geological time scales. Various CO 2 reduction approaches have been evaluated, and the weathering acceleration method is expected to be a low-cost approach. This study attempts to estimate carbonate precipitation potential and dissolution rate from alkali leaching rates using weathering tests on mafic rocks. Based on Japan's annual average rainfall, the in situ carbonate precipitation potential obtained by spreading an olivine mineral or basalt rock powder at 40 ton-powder/ha was on the order of 10 -3 ton/year/ton-rock. This weathering rate could not be greatly accelerated under natural temperature conditions and fine granulation of the minerals.

Variation among Blackgram (Vigna mungo L.) Genotypes for Antioxidant Defence System and Yield under High Temperature Stress

Background: Blackgram is a short duration pulse crop which is sensitive to high temperatures. Raising global temperatures are becoming a serious threat to the production of blackgram by altering biochemical processes at cellular level. Hence, the present investigation was carried out for better understanding of genotypic variability and the biochemical mechanisms governing heat stress tolerance which can help in identifying heat tolerant blackgram genotypes that can yield better under climate change scenarios. Methods: Thirty blackgram genotypes selected from temperature induction response technique were evaluated for biochemical efficiency under natural high temperature conditions during summer, 2022 and 23. Field experiment was conducted at Agricultural College Farm, Acharya N.G Ranga Agricultural University, Agricultural College, Bapatla. Biochemical and yield parameters were recorded at flowering and the data were analyzed statistically and pooled. Result: The results of the study revealed that the genotypes TBG-129, LBG-1015, PU-1804 and PU-31 recorded higher seed yield indicating their ability to withstand high temperatures by up-regulating various biochemical pathways involved in increased production of proline, carotenoids and antioxidant defense enzymes that might have scavenged the free radicals that were produced due to high temperature stress, thereby preventing lipid peroxidation. Lower seed yield was recorded in TBG-125 and LBG-1023 which might be due to oxidative damage caused by higher accumulation of free radicals and poor scavenging activity of antioxidant enzymes. Moreover, the results of correlation analysis revealed that all the biochemical traits such as proline, carotenoids and antioxidant defense enzymes showed positive association with seed yield except free radicals and malondialdehyde. The principal component analysis results revealed considerable variability among the traits accounting for 80.0%. The genotypes TBG-129, LBG-1015, PU-1804 and PU-31 can be used in breeding programmes for development of heat tolerant genotypes.

Trends in Greenhouse Production Technology with Special Reference to Protected Cultivation of Horticultural Crops

Greenhouse is an important application scenario of modern agriculture. With the improvement of people's life quality, the demand for vegetables, fruits, flowers and has also increased, and the amount of greenhouses has developed rapidly. Greenhouse adopts artificial technical means to change natural light and temperature conditions, and to create environmental factors to optimize the growth of animals and plants, so that greenhouse crops can grow throughout the year and the weather. Compared with traditional planting methods, the greenhouse is more automated, intelligent, and mechanized. Greenhouse farming (Protected cultivation) refers to the practice of growing crops in an enclosed or partially enclosed environment, such as greenhouses, shade houses, or high tunnels. The primary purpose of protected cultivation is to create a controlled microclimate that shields the crops from adverse weather conditions, pests, and diseases, while optimizing environmental factors. It involves the use of structures, materials, and technologies that provide a protective barrier and allow for manipulation of temperature, humidity, light, and other environmental variables. The benefits of greenhouses are high production per unit area because the genetic potential of the crop can be completely exploited, vegetables and nurseries can be grown off-season that obtain high market prices, good quality products and it is easy to protect the crops from pests, diseases and extreme climatic conditions. Greenhouse farming is a highly intensive industry that needs considerable labour and capital inputs. Because of this, all factors important for a successful enterprisers should be carefully considered by potential growers.

Antibiotic Degradation via Fenton Process Assisted by a 3-Electron Oxygen Reduction Reaction Pathway Catalyzed by Bio-Carbon-Manganese Composites.

Bio-carbon-manganese composites obtained from olive mill wastewater were successfully prepared using manganese acetate as the manganese source and olive wastewater as the carbon precursor. The samples were characterized chemically and texturally by N2 and CO2 adsorption at 77 K and 273 K, respectively, by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. Electrochemical characterization was carried out by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The samples were evaluated in the electro-Fenton degradation of tetracycline in a typical three-electrode system under natural conditions of pH and temperature (6.5 and 25 °C). The results show that the catalysts have a high catalytic power capable of degrading tetracycline (about 70%) by a three-electron oxygen reduction pathway in which hydroxyl radicals are generated in situ, thus eliminating the need for two catalysts (ORR and Fenton).

Evaluation of Blackgram (Vigna mungo L.) Genotypes for Dry Matter Partitioning, Reproductive Efficiency and Yield under High Temperature Stress

Background: In the present climate change scenario, the rising temperatures are imposing severe threat to blackgram production leading to marked reduction in yield potential.The reduction in the yield potential is mainly due to reproductive failures caused by heat stress. Keeping this in view, the present study was carried out to find out the reasons behind reproductive failures and identify the genotypes that yield better under heat stress. Methods: Thirty blackgram genotypes selected from temperature induction response technique were evaluated for reproductive efficiency under natural high temperature conditions. Field experiment was conducted at Agricultural College Farm, Acharya N.G Ranga Agricultural University, Agricultural College, Bapatla. Dry matter partitioning, reproductive efficiency and yield traits were recorded at flowering and the data were analyzed statistically and pooled. Result: Genetic variability was observed among the blackgram genotypes with respect to dry matter partitioning, reproductive efficiency and yield traits under high temperature stress conditions. Among the 30 genotypes tested for thermotolerance, the genotypes TBG-129, PU-1804 and LBG-1015 were found to withstand high temperature stress at reproductive stage by possessing higher dry matter, number of flowers per plant, pollen viability, pollen germination percentage, pollen load on stigma, stigma receptivity, flower to pod setting percentage and higher yield. Correlation analysis revealed a strong positive association of total dry matter and all the reproductive efficiency characteristics with seed yield under heat stress conditions. The PCA results revealed considerable variability among the traits accounting for 86.6% of total variability. The genotypes TBG-129, PU-1804 and LBG-1015 can be potentially used as donors in the breeding programmes for the development of heat tolerant genotypes.

High temperature and solar radiation in the Red Sea enhance the dissolution of crude oil from surface films

The Red Sea is a hotspot of biodiversity susceptible to oil pollution. Besides, it is one of the warmest seas on the Earth with highly transparent waters. In this study, we estimated the oil dissolution rates under natural sunlight spectra and temperature conditions using coastal oil slicks collected after the 2019 Sabiti oil spill in the Red Sea. Optical analyses revealed the significant interactive effect of sunlight and temperature in enhancing the dissolution of oil into dissolved organic matter (DOM). The highest oil dissolution rate (38.68 g C m−3 d−1) was observed in full-spectrum sunlight. Oil dissolution significantly enhanced total organic carbon (TOC) and polycyclic aromatic hydrocarbons (PAHs) in seawater. High nucleic acid (HNA) bacteria, likely the oil degraders, proliferated from 30 to 70 – 90% after 4 days. The heavier stable carbon isotopic composition of methane (δ13C-CH4) and lighter stable carbon isotopic composition of carbon dioxide (δ13C-CO2) indicate the putative role of bacterial processes in the natural degradation of crude oil. The results indicated that the combined effect of temperature and solar radiation enhanced the biological and photochemical dissolution of oil on the Red Sea surface.

Research Note: Water applied direct-fed microbial reduced mortality in heat stressed broilers

Pressure to reduce the use of antibiotics in the poultry industry has intensified research on alternative solutions to support intestinal health, including but not limited to direct fed microbials (DFM). Heat stress is known to impact intestinal health and function. The aim of this study was to determine efficacy of a water applied DFM product on broiler performance during the summer period. One of two treatments were randomly allocated to 12 replicate floor pens each: a control treatment and a treatment provided daily with a dual strain DFM comprised of Lactobacillus acidophilus AG01 and Bifidobacterium animalis AG02 at 1 × 108 CFU/bird/d. Each pen contained 20 Ross 308 broilers. All birds were fed the same three-phased wheat- and soybean meal-based diets. Body weight, feed intake, feed conversion ratio, and mortality were measured at d 0, 10, 24, 35, and 42. Due to natural extreme external temperature conditions, all birds were subject to heat stress during the end of the grower phase up to and including the finisher phase. Temperature was on average 5°C higher compared to industry recommendation. No significant differences were found in growth performance between the control and DFM treatment, yet BW at d 42 in both treatments was reduced by 19% compared to the breed standard. The DFM treatment significantly reduced mortality among the birds. Overall mortality from d 1 to d 35 was reduced from 4.58% to 0.42% (P = 0.023) and overall mortality from d 1 to d 42 was reduced from 5.83 to 0.83% (P = 0.027). This was driven by the difference in heat-stress related mortality in the finisher phase from d 25 to d 42, where mortality reached only 0.44% in the DFM treatment versus 2.88% in the unsupplemented control treatment. Post-mortem analysis confirmed heat-stress related hypoxia. In conclusion, the dual strain DFM may have provided improved (intestinal) homeostasis and barrier function allowing increased resilience to heat stress in broilers.

Incubation and Larval Development Durations of Sterlet (A. ruthenus LINNAEUS 1758) in River Water Rearing under Near-Natural Conditions

Day-degrees [°D], also known as accumulated thermal units (ATUs), have been used to predict the duration of early development for fish. For most sturgeon species, the available data in the literature were determined under temperature-constant conditions. However, there is a lack of information on ATUs of early development for sturgeons under natural or near-natural temperature conditions. The aim of this study was to observe the duration of incubation and the duration from hatch until feeding of sterlets (Acipenser ruthenus) under near-natural conditions. This study was embedded within the LIFE-Sterlet and LIFE-Boat 4 Sturgeon project and data were gathered from the year 2017 to 2023. The rearing of fish larvae took place in the project hatchery container with Danube water without biological, chemical, or thermal water treatment to simulate natural conditions. Temperatures [°C] were monitored on a daily basis and day-degrees were calculated by summing the temperature over time. Results indicated slower larval development than described in the literature. Hatching started earliest after 7 days at 106 °D and latest after 151 °D. Feeding started between 155 and 271 °D. The findings of this study provide valuable insights into the temperature-dependent development of sterlet larvae under near-natural conditions and can assist in the design of optimal rearing of sturgeons for conservation efforts.

Evaluation of electrode separators and the external resistance in electrochemically assisted constructed wetlands

A proton exchange membrane increases the electrical performance of a microbial fuel cell (MFC). New inexpensive materials should be sought, especially in a constructed wetland microbial fuel cell (CW-MFC). Here, in a laboratory-scale system of five CW-MFCs, wet clay, wet earth or mud, and non-woven cloth were used as inexpensive separators with long-term stability. The five CW-MFCs were planted with Typha latifolia, fed with synthetic wastewater, and packed with natural porous material. Graphite felt was used as electrodes and the experimental system had a hydraulic residence time of 3 days, operating under shade and natural conditions of temperature and light. Electrodes were connected to current collectors (copper wire) and to an external resistance, with a change every 20 days, starting in open-circuit and following with 20000, 18000, 15000, 10000, 5600, 1000, 560, and 10 Ω. These laboratory-scale CW-MFCs reduced concentrations of nitrates, ammonium ion, and sulfates without inhibiting electricity production. Microbiological analyses indicated that anaerobic, facultative, aerobic, and denitrifying bacteria may have caused these reductions. The reactor with the live plant and with the wet earth or mud separator achieved the highest production of electricity (22.6 mW/m2), and may be worth further attention.

Variation in Physiological Traits of Blackgram (Vigna mungo L.) Genotypes under High Temperature Stress

Background: Blackgram is one of the important short duration pulse crop which is sensitive to high temperatures. The rising global temperatures are threatening the yield of blackgram by altering the physiological processes at cellular level. Keeping this in view, the present investigation was carried out for better understanding of genotypic variability and the physiological mechanisms governing heat stress tolerance which can help in identifying heat tolerant blackgram genotypes that can yield better under climate change scenarios. Methods: Thirty blackgram genotypes selected from temperature induction response technique were evaluated for physiological efficiency under natural high temperature conditions during summer, 2022 and 2023. Field experiment was conducted at Agricultural College Farm, Acharya N.G Ranga Agricultural University, Agricultural College, Bapatla. Physiological and yield parameters were recorded at flowering and the data were analyzed statistically and pooled. Result: Significant genetic variability was observed among the blackgram genotypes with respect to all the physiological traits under high temperature stress conditions. Among the 30 genotypes tested for thermotolerance, the genotypes TBG-129, PU-1804, LBG-1015, PU-31 and TBG-104 were found to withstand high temperature stress at reproductive stage by maintaining higher total chlorophyll, carotenoids, chlorophyll stability index, total biomass production, cooler canopies resulting into higher canopy temperature depression, less membrane injury index values and higher yield. Correlation analysis revealed a strong positive correlation for all the physiological traits with seed yield except membrane injury index under heat stress conditions. The PCA results revealed considerable variability among the traits accounting for 82.65% of total variability. The genotypes TBG-129, PU-1804, LBG-1015 and TBG-104 can be potentially used as donors in the breeding programmes for the development of heat tolerant genotypes.

Outdoor cultivation and metabolomics exploration of Chlamydomonas engineered for bisabolene production

Demonstrating outdoor cultivation of engineered microalgae at considerable scales is essential for their prospective large-scale deployment. Hence, this study focuses on the outdoor cultivation of an engineered Chlamydomonas reinhardtii strain, 3XAgBs-SQs, for bisabolene production under natural dynamic conditions of light and temperature. Our preliminary outdoor experiments showed improved growth, but frequent culture collapses in conventional Tris-acetate-phosphate medium. In contrast, modified high-salt medium (HSM) supported prolonged cell survival, outdoor. However, their subsequent outdoor scale-up from 250 mL to 5 L in HSM was effective with 10 g/L bicarbonate supplementation. Pulse amplitude modulation fluorometry and metabolomic analysis further validated their improved photosynthesis and uncompromised metabolic fluxes towards the biomass and the products (natural carotenoids and engineered bisabolene). These strains could produce 906 mg/L bisabolene and 54 mg/L carotenoids, demonstrating the first successful outdoor photoautotrophic cultivation of engineeredC. reinhardtii,establishing it as a one-cell two-wells biorefinery.

COOLAIR and PRC2 function in parallel to silence FLC during vernalization

Noncoding transcription induces chromatin changes that can mediate environmental responsiveness, but the causes and consequences of these mechanisms are still unclear. Here, we investigate how antisense transcription (termed COOLAIR) interfaces with Polycomb Repressive Complex 2 (PRC2) silencing during winter-induced epigenetic regulation of Arabidopsis FLOWERING LOCUS C (FLC). We use genetic and chromatin analyses on lines ineffective or hyperactive for the antisense pathway in combination with computational modeling to define the mechanisms underlying FLC repression. Our results show that FLC is silenced through pathways that function with different dynamics: a COOLAIR transcription-mediated pathway capable of fast response and in parallel a slow PRC2 switching mechanism that maintains each allele in an epigenetically silenced state. Components of both the COOLAIR and PRC2 pathways are regulated by a common transcriptional regulator (NTL8), which accumulates by reduced dilution due to slow growth at low temperature. The parallel activities of the regulatory steps, and their control by temperature-dependent growth dynamics, create a flexible system for registering widely fluctuating natural temperature conditions that change year on year, and yet ensure robust epigenetic silencing of FLC.

The metabolomics and transcriptomics of Atraphaxis bracteata reveal age‐related molecular alterations under naturally high temperature and drought conditions

AbstractHigh temperature and drought are common environmental stresses that desert plants must withstand to grow and reproduce. In order to understand the resistance mechanisms of the desert plant Atraphaxis bracteata (A. Los) responding to natural high temperature and drought conditions, we combined physiological characteristics, transcriptome, and metabolome analysis to explore its responses in three different plant ages and CK. The results showed that most physiological indicators of A. bracteata increased with the age, except for SOD activity. There were 4 698, 7 594, and 8 485 differentially expressed genes (DEGs) and 119, 124, 188 differential expressed metabolites (DAMs) in the 3‐age‐old (T1), 5‐age‐old (T2) and 15‐age‐old (T3) plants compared to the CK, respectively. These DEGs were mainly enriched in plant hormone signal transduction, phenylpropanoid biosynthesis, AMPK signalling pathway, flavonoid biosynthesis, circadian rhythm‐plant pathways, glycine, serine, and threonine metabolism pathways. At the same time, the enriched DAMs were mainly involved in the aminoacyl‐tRNA biosynthesis pathway, arginine and proline metabolism pathway, flavonoid biosynthesis, and others. In addition, most DEGs involved in flavonoid biosynthesis, photosynthesis and plant hormones closely associated with abiotic stress were down‐regulated, and which numbers increased with age. Moreover, a higher number of DEGs and DAMs accumulated with age, which may be the key factor for the age‐dependent resistance of A. bracteata to abiotic stress. Therefore, these results could provide a way to better understand the stress resistance mechanism and provide a reference for further exploitation and utilization of A. bracteata.

SCIENTIFIC SUBSTANTIATION OF THE PRODUCTIVITY OF SOWING ALFALFA DEPENDING ON SOIL AND CLIMATIC CONDITIONS OF THE FOREST-STEPPE OF UKRAINE

The article presents a review of literature sources on the study of alfalfa productivity depending on the influence of sowing dates, mineral phosphorus-potassium nutrition, soil liming, pre-sowing seed treatment with bacterial preparations and modes of grass stand use when grown for fodder purposes. It was found that the change of photoperiod in the year of sowing was a signal in alfalfa plants to pass through the microstages of growth and development, which was determined by the length of daylight hours and sowing dates, regardless of hydrothermal resources. Observations showed that the crop reached the beginning of flowering phase (code 61-62 of the BBSN) at daylight hours of 14:53-16:12 h, while at 12:48 h it reached the budding phase (code 49 of the BBSN). Regardless of climate change, which has been observed for more than a decade, sowing alfalfa provided the highest productivity indicators with early spring sowing and long-term use of the grass stand. Over the three years of vegetation, its leaf mass yield averaged 47.03 t/ha, dry matter yield was 11.09 and 2.07 t/ha of crude protein, and gross and metabolizable energy were 204.72 and 104.52 GJ/ha, respectively. At the same time, with the recommended summer sowing date (20 July), the indicators decreased by 9.1, 11.5, 13.1, 12.2 and 11.7%, respectively. Analysing the agro-ecological resources of Ukraine, given the natural soil fertility, moisture, temperature and light conditions, they are quite favourable for the maximum realisation of the biological potential of the fodder productivity of sowing alfalfa within the yield of fodder units of 10-12 t/ha and 1.8-2.2 t/ha of digestible protein. Among the elements of intensifying the cultivation of seed alfalfa for the production of plant raw materials and harvesting of various types of fodder, fertilisation is the most effective factor influencing their quantity and quality. To calculate the amount of mineral fertiliser, we take into account the biological characteristics of the crop, its cyclical growth and development during the growing season, the method of sowing and the duration of grassland use. Regardless of the geographical origin of the seed alfalfa, for two years of using the grass stand and observing technological measures of cultivation (lime, phosphorus-potassium mineral fertilisers, seed inoculation), alfalfa provided the highest yield of crude protein of 5.83-5.97 t/ha when mowing the first mowing in the flowering phase, the second - at the beginning of flowering and the third in the budding phase. Mowing of three mowings of sowing alfalfa at the beginning of the flowering phase contributes to the effective use of the light regime of the growing season as the main factor in increasing productivity. Innovative technologies for growing seed alfalfa use growth-regulating agents of various origins, microfertilisers and biological seed treatment products to increase yields and dry matter quality for foliar feeding. The complex application of these preparations provides an increase in the yield of leaf mass by 16.6-18.2%. Thus, in the context of modern agricultural development, alfalfa is one of the components of reducing the anthropogenic load on the agro-ecological system and increasing the production of environmentally friendly high-protein feed and livestock products for the purpose of efficient use of hydrothermal resources and environmental protection.

Impact of wildfire ash on bacterioplankton abundance and community composition in a coastal embayment (Ría de Vigo, NW Spain)

Wildfire ash can have an impact on coastal prokaryotic plankton. To understand the extent to which community composition and abundance of coastal prokaryotes are affected by ash, two ash addition experiments were performed. Ash from a massive wildfire that took place in the Ría de Vigo watershed in October 2017 was added to natural surface water samples collected in the middle sector of the ría during the summer of 2019 and winter of 2020, and incubated for 72 h, under natural water temperature and irradiance conditions. Plankton responses were assessed through chlorophyll a and bacterial abundance measurements. Prokaryotic DNA was analyzed using 16S rRNA gene partial sequencing. In summer, when nutrient concentrations were low in the ría, the addition of ash led to an increase in phytoplankton and bacterial abundance, increasing the proportions of Alteromonadales, Flavobacteriales, and the potentially pathogenic Vibrio, among other taxa. After the winter runoff events, nutrient concentrations in the Ría de Vigo were high, and only minor changes in bacterial abundance were detected. Our findings suggest that the compounds associated with wildfire ash can alter the composition of bacterioplanktonic communities, which is relevant information for the management of coastal ecosystems in fire-prone areas.

Molecular dynamics, molecular docking, DFT, and ADMET investigations of the Co(II), Cu(II), and Zn(II) chelating on the antioxidant activity and SARS-CoV-2 main protease inhibition of quercetin

The natural flavonol quercetin (Q) is found in many vegetables, fruits, and beverages, and it is known as a strong antioxidant. Its metal ion chelation may increase its antioxidant activity. The present study aims to explore the Co(II), Cu(II), and Zn(II) chelating on the antioxidant effectiveness and severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) main protease (Mpro) inhibitory of quercetin using Density-functional theory (DFT), molecular docking, and molecular dynamics simulations (MD). DFT calculations at the B3LYP/LanL2DZ reveal that the high antioxidant activity of the metal-chelated quercetin complexes is mainly returned to their lower ionization potentials (IPs) compared with the one of the free quercetin. Molecular docking of quercetin and its Co(II), Cu(II), and Zn(II) chelates into the active binding sites of peroxiredoxin 5 and SARS-CoV-2 main protease (Mpro) were performed using Lamarckian Genetic Algorithm method. The docked quercetin and its metal chelates fit well into the binding site of the target proteins, and their binding affinity is strongly influenced by the type of the chelated metals Co(II), Cu(II), and Zn(II), and molar ratio metal: ligand, i.e. 1:2 and 2:1. Further, the binding stability of QZn2 and QCu2 in peroxiredoxin 5 and SARS-CoV-2 main protease targets is evaluated using MD simulation conducted for 100 ns simulations at natural room temperature conditions, and the obtained results showed that all chelates remain bound to the ligand binding groove of protein except for 1HD2_QZn2 complex. Finally, the adsorption, distribution, metabolism, excretion, and toxicity (ADMET) and drug-likeness properties of quercetin and cobalt(II)-quercetin (QCo2(II)) were investigated. Communicated by Ramaswamy H. Sarma

Penguin guano trace metals release to Antarctic waters: A kinetic modelling

Penguin guano has been considered as a suitable bioindicator of the exposure to environmental contaminants in Antarctic environment. Although trace metal content values in penguin guano have been widely reported, the kinetics of their mobility in seawater have not been determined. In the present study, we have estimated the release rate of dissolved Cd, Co, Cu, Fe, Mn, Mo, Ni, Pb, V, and Zn from Gentoo (Pygoscelis papua) penguins guano to Antarctic seawater by 120 h laboratory and at external natural conditions of temperature and light experiments. A mathematical model using two metal pools guano (labile and equilibrium) and seawater compartments considering pseudo-first-order kinetics, is proposed in order to interpret and predict the release of trace metals. A good statistical agreement between experimental and modelled concentration values allows us obtention of kinetic parameters and partition coefficients (Kdi). These values allow to estimate releases into seawater from 5400 to 6.3 μg/day·penguin of Cu and V, respectively. More than 50 % of the initial content of all the studied elements are released during the first two hours, reaching 90 % release in the decreasing order of speed Ni ≫ Cu ≈ Mo > Mn > Co > Cd ≈ Pb; periods of up to one hour, Fe, V and Zn reach a maximum release and are then readsorbed. Equilibrium releases >90 % for Mo and Cd, and 55 % - 46 % for Co, Ni, Pb and Mn are obtained; Zn with 5.4 %, V with 1.7 % and Fe with 0.88 % show the lowest values. With an overwhelming growth of estimated population south of 60°S of 259.750 breeding pairs we estimate that the Gentoo penguin population is releasing annually in the Southern Ocean, 716 kg Cu, 188 kg Mn, 113 kg Fe, 102 kg Zn, 17.7 kg Mo, 12.0 kg Ni, 8.70 kg Cd, 4.59 kg Co, 6.27 kg Pb and 0.790 kg V of soluble metals.

Application of the disturb and observe algorithm together with a control system for the boost converter in photovoltaic applications

The boost-boost converter presents interesting characteristics for photovoltaic applications, due to the nature of the system where we can increase the voltage in an adequate and controlled way according to the load, in combination with an optimal control system we can obtain a better efficiency of an autonomous photovoltaic system, taking into consideration that a solar panel within its most significant properties to operate within the most efficient way needs natural conditions of irradiation and temperature that are closest to the SCT measurement standard, otherwise efficiency will be lost, Therefore, it is necessary to jointly implement a control system together with an algorithm that allows it to always be in maximum power conditions (MPP). According to the above, this article addresses the low voltage photovoltaic application of an isolated system, using a boost converter and a PI control system, together with an algorithm for obtaining the maximum power point, using two different photovoltaic systems, with the objective of showing that with an essential PI control we can obtain good efficiency of the two systems even with disturbances, as if a more robust control were implemented in photovoltaic applications, saving both operation cost and implementation time. The I-V (current-voltage) characteristics similar to a non-linear source of the photovoltaic module, require the inclusion of linearization of the photovoltaic module and with this to be able to design the control of the system, the proper functioning of the designed control has been tested through mathematical modeling and simulation.

Steroidogenic potential of the gonad during sex differentiation in the rice field frog Hoplobatrachus rugulosus (Anura: Dicroglossidae).

Prior studies demonstrated that gonadal differentiation in the rice field frog, Hoplobatrachus rugulosus, was of an undifferentiated type since all individuals had ovaries at complete metamorphosis. However, the steroidogenic potential of the gonad is still unknown. In this study, H. rugulosus were obtained by stimulating fertilization in the laboratory under natural light and temperature conditions. The gonads were collected and their steroidogenic potential was evaluated by determining the expression level of messenger RNA (mRNA) encoding for cytochrome P450 17-hydroxylase/C17-20 lyase (CYP17) and cytochrome P450 aromatase (CYP19) using quantitative real-time RT-PCR and the localization of CYP17 mRNA in tissues by in situ hybridization. The CYP17 mRNA levels in males at 4-11 weeks postmetamorphosis were higher than in female and intersex gonads. This corresponded to their localization in the gonadal tissues, where CYP17 signals were specifically detected in the Leydig cells of the testis at 5-16 weeks postmetamorphosis but was undetectable in all ovary samples. The CYP19 mRNA levels in females at 4-11 weeks postmetamorphosis was higher than in male and intersex gonads, which corresponded with gonadal development, indicating the potential steroidogenic function of the ovary. Based on the present results, the role of CYP17 and CYP19 mRNA in sex differentiation in H. rugulosus may occur after gonadal sex differentiation and the steroidogenic potential of the gonads exhibited a sexual dimorphic pattern. These results provide a crucial basis for further research on the developmental biology in anuran species.

Contrasting torpor use by reproductive male common noctule bats in the laboratory and in the field.

Metabolic processes of animals are often studied in controlled laboratory settings. However, these laboratory settings often do not reflect the animals' natural environment. Thus, results of metabolic measurements from laboratory studies must be cautiously applied to free-ranging animals. Recent technological advances in animal tracking allow detailed eco-physiological studies that reveal when, where and how physiological measurements from the field differ from those from the laboratory. We investigated torpor behavior of male common noctule bats (Nyctalus noctula) across different life history stages using two approaches: in controlled laboratory experiments and in the field using calibrated heart rate telemetry. We predicted that non-reproductive males would extensively use torpor to conserve energy, whereas reproductive males would reduce torpor use to promote spermatogenesis. We did not expect differences in torpor use between captive and wild animals as we simulated natural temperature conditions in the laboratory. We found that during the non-reproductive phase, both captive and free-ranging bats used torpor extensively. During reproduction, bats in captivity unexpectedly also used torpor throughout the day, while only free-ranging bats showed the expected reduction in torpor use. Thus, depending on life history stage, torpor behavior in the laboratory was markedly different from the wild. By implementing both approaches and at different life history stages, we were able to better explore the limitations of eco-physiological laboratory studies and make recommendations for when they are an appropriate proxy for natural behavior.