Auswahl der wissenschaftlichen Literatur zum Thema „CO2 vents“
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Zeitschriftenartikel zum Thema "CO2 vents"
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Zitoun, R., S. D. Connell, C. E. Cornwall, K. I. Currie, K. Fabricius, L. J. Hoffmann, M. D. Lamare et al. „A unique temperate rocky coastal hydrothermal vent system (Whakaari–White Island, Bay of Plenty, New Zealand): constraints for ocean acidification studies“. Marine and Freshwater Research 71, Nr. 3 (2020): 321. http://dx.doi.org/10.1071/mf19167.
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In situ effects of ocean acidification are increasingly studied at submarine CO2 vents. Here we present a preliminary investigation into the water chemistry and biology of cool temperate CO2 vents near Whakaari–White Island, New Zealand. Water samples were collected inside three vent shafts, within vents at a distance of 2m from the shaft and at control sites. Vent samples contained both seawater pH on the total scale (pHT) and carbonate saturation states that were severely reduced, creating conditions as predicted for beyond the year 2100. Vent samples showed lower salinities, higher temperatures and greater nutrient concentrations. Sulfide levels were elevated and mercury levels were at concentrations considered toxic at all vent and control sites, but stable organic and inorganic ligands were present, as deduced from Cu speciation data, potentially mediating harmful effects on local organisms. The biological investigations focused on phytoplankton, zooplankton and macroalgae. Interestingly, we found lower abundances but higher diversity of phytoplankton and zooplankton at sites in the direct vicinity of Whakaari. Follow-up studies will need a combination of methods and approaches to attribute observations to specific drivers. The Whakaari vents represent a unique ecosystem with considerable biogeochemical complexity, which, like many other vent systems globally, require care in their use as a model of ‘future oceans’.
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Lauritano, C., M. Ruocco, E. Dattolo, M. C. Buia, J. Silva, R. Santos, I. Olivé, M. M. Costa und G. Procaccini. „Response of key stress-related genes of the seagrass <i>Posidonia oceanica</i> in the vicinity of submarine volcanic vents“. Biogeosciences Discussions 12, Nr. 6 (30.03.2015): 4947–71. http://dx.doi.org/10.5194/bgd-12-4947-2015.
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Abstract. Submarine volcanic vents are being used as natural laboratories to assess the effects of CO2 on marine organisms and communities, as this gas is the main component of emissions. Seagrasses should positively react to increased dissolved carbon, but in vicinity of volcanic vents there may be toxic substances, that can have indirect effects on seagrasses. Here we analysed the expression of 35 stress-related genes in the Mediterranean keystone seagrass species P. oceanica in the vicinity of submerged volcanic vents located in the Islands of Ischia and Panarea, Italy, and compared them with those from control sites away from the influence of vents. Reverse Transcription-Quantitative Polymerase Chain Reaction (RT-qPCR) was used to characterize the expression levels of genes. Fifty one per cent of genes analysed showed significant expression changes. Metal detoxification genes were mostly down-regulated in relation to controls both in Ischia and Panarea locations, indicating that P. oceanica does not increase the synthesis of heavy metal detoxification proteins in response to the environmental conditions present at the two vents. The expression levels of genes involved in free radical detoxification indicate that, in contrast with Ischia, P. oceanica at the Panarea vent face stressors that result in the production of reactive oxygen species triggering antioxidant responses. In addition, heat shock proteins were also activated at Panarea and not at Ischia. Overall, our study reveals that P. oceanica is generally under higher stress in the vicinity of the vents at Panarea than at Ischia, possibly resulting from environmental and evolutionary differences existing between the two volcanic sites. This is the first study analysing gene responses in marine plants living near natural CO2 vents and our results call for a careful consideration of factors, other than CO2 and acidification, that can cause stress to seagrasses and other organisms near volcanic vents.
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Sharma, S., und D. G. Williams. „Carbon and oxygen isotope analysis of leaf biomass reveals contrasting photosynthetic responses to elevated CO<sub>2</sub> near geologic vents in Yellowstone National Park“. Biogeosciences Discussions 5, Nr. 5 (17.09.2008): 3825–43. http://dx.doi.org/10.5194/bgd-5-3825-2008.
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Abstract. In this study we explore the use of natural CO2 emissions in Yellowstone National Park (YNP) in Wyoming, USA to study responses of natural vegetation to elevated CO2 levels. Radiocarbon (14C) analysis of leaf biomass from a conifer (Pinus contortus; lodgepole pine) and an invasive, non-native herb (Linaria dalmatica; Dalmation toadflax) was used to trace the inputs of vent CO2 and quantify assimilation-weighted CO2 concentrations experienced by individual plants near vents and in comparable locations with no geologic CO2 exposure. The carbon and oxygen isotopic composition and nitrogen percent of leaf biomass from the same plants was used to investigate photosynthetic responses of these plants to naturally elevated atmospheric CO2 concentrations. The coupled shifts in carbon and oxygen isotope values suggest that dalmation toadflax responded to elevated CO2 exposure by increasing stomatal conductance with no change in photosynthetic capacity and lodgepole pine apparently responded by decreasing stomatal conductance and photosynthetic capacity. Lodgepole pine saplings exposed to elevated levels of CO2 likewise had reduced leaf nitrogen concentrations compared to plants with no enhanced CO2 exposure, further suggesting that this widespread and dominant conifer down-regulated photosynthetic capacity under elevated CO2 levels near geologic vents.
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Sharma, S., und D. G. Williams. „Carbon and oxygen isotope analysis of leaf biomass reveals contrasting photosynthetic responses to elevated CO<sub>2</sub> near geologic vents in Yellowstone National Park“. Biogeosciences 6, Nr. 1 (07.01.2009): 25–31. http://dx.doi.org/10.5194/bg-6-25-2009.
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Abstract. In this study we explore the use of natural CO2 emissions in Yellowstone National Park (YNP) in Wyoming, USA to study responses of natural vegetation to elevated CO2 levels. Radiocarbon (14C) analysis of leaf biomass from a conifer (Pinus contortus; lodgepole pine) and an invasive, non-native herb (Linaria dalmatica; Dalmation toadflax) was used to trace the inputs of vent CO2 and quantify assimilation-weighted CO2 concentrations experienced by individual plants near vents and in comparable locations with no geologic CO2 exposure. The carbon and oxygen isotopic composition and nitrogen percent of leaf biomass from the same plants was used to investigate photosynthetic responses of these plants to naturally elevated atmospheric CO2 concentrations. The coupled shifts in carbon and oxygen isotope values suggest that dalmation toadflax responded to elevated CO2 exposure by increasing stomatal conductance with no change in photosynthetic capacity and lodgepole pine apparently responded by decreasing stomatal conductance and photosynthetic capacity. Lodgepole pine saplings exposed to elevated levels of CO2 likewise had reduced leaf nitrogen concentrations compared to plants with no enhanced CO2 exposure, further suggesting widespread and dominant conifer down-regulated photosynthetic capacity under elevated CO2 levels near geologic vents.
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Nike Bianchi, Carlo, Paul R. Dando und Carla Morri. „Increased diversity of sessile epibenthos at subtidal hydrothermal vents: seven hypotheses based on observations at Milos Island, Aegean Sea“. Advances in Oceanography and Limnology 2, Nr. 1 (17.06.2011): 1. http://dx.doi.org/10.4081/aiol.2011.5314.
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Research on subtidal hydrothermal vent ecosystems at Milos, Hellenic Volcanic Arc (Aegean Sea), suggested that vent activity increased the species richness of sessile epibenthic assemblages. Based on 303 species found in 6 sites (3 close to vents, 3 farther away), the present paper uses correspondence analysis and species/samples curves to examine the species composition and richness of these assemblages. Differences due to vent proximity were more important than those due to bottom depth and distance from the shore. Diversity was confirmed to be higher near the vents, although none of the 266 species found at the vent sites can be considered as obligate vent-associated species. Seven different, although not mutually exclusive, hypotheses are discussed to explain the pattern of increased epibenthic species diversity at the vent sites, namely: (i) vents represent an intermediate disturbance, inducing mortality by the emission of toxic fluids; (ii) higher winter temperature allows for the occurrence of warm-water species, which add to the regional background; (iii) venting disrupts the homogeneity of the water bottom layer, increasing bottom roughness and hence habitat heterogeneity; (iv) deposition of minerals and enhanced bioconstruction by Ca enrichment increment habitat provision; (v) fluid emission induces advective mechanisms that favour recruitment; (vi) vents emit CO2, nutrients and trace elements that enhance primary productivity; and (vii) bacterial chemosynthesis add to photosynthesis to provide a diversity of food sources for the fauna.
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Nurmalisa, Moliya, Takayuki Tokairin, Tadashi Kumazaki, Kotaro Takayama und Takanobu Inoue. „CO2 Distribution under CO2 Enrichment Using Computational Fluid Dynamics Considering Photosynthesis in a Tomato Greenhouse“. Applied Sciences 12, Nr. 15 (01.08.2022): 7756. http://dx.doi.org/10.3390/app12157756.
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This study validated the CO2 distribution predicted by a computational fluid dynamics model considering CO2 absorption by photosynthesis in a chamber and greenhouse. The effect of photosynthesis with CO2 emission from a perforated tube remains not fully understood, although previous studies on CO2 distribution in greenhouses have been conducted. Moreover, comparisons between CO2 concentration measurement and simulation were obtained in the chamber and greenhouse model. Cases with open and closed side vents of the greenhouse showed that closed side vents have slightly more even of CO2 concentration than those with open side vents inside the greenhouse. In contrast, the coefficient of variance (CV) of CO2 inside the plant, open (8.8%) and closed (8.7%) side vents, induced almost no significant improvement. Additionally, cases of a rainy- and sunny-day model showed that photosynthetically active radiation possibly compensated CO2 absorption through photosynthesis to be low at low light (rainy day) and higher at high light (sunny day). Nonetheless, the variability of CO2 concentration inside the plant between rainy and sunny days determined almost no significant difference. Thus, this research shows characteristics of CO2 distribution, assessing photosynthesis and the variability of CO2 concentration that leads to the efficiency of CO2 enrichment in the greenhouse.
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Lauritano, C., M. Ruocco, E. Dattolo, M. C. Buia, J. Silva, R. Santos, I. Olivé, M. M. Costa und G. Procaccini. „Response of key stress-related genes of the seagrass <i>Posidonia oceanica</i> in the vicinity of submarine volcanic vents“. Biogeosciences 12, Nr. 13 (15.07.2015): 4185–94. http://dx.doi.org/10.5194/bg-12-4185-2015.
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Abstract. Submarine volcanic vents are being used as natural laboratories to assess the effects of increased ocean acidity and carbon dioxide (CO2) concentration on marine organisms and communities. However, in the vicinity of volcanic vents other factors in addition to CO2, which is the main gaseous component of the emissions, may directly or indirectly confound the biota responses to high CO2. Here we used for the first time the expression of antioxidant and stress-related genes of the seagrass Posidonia oceanica to assess the stress levels of the species. Our hypothesis is that unknown factors are causing metabolic stress that may confound the putative effects attributed to CO2 enrichment only. We analyzed the expression of 35 antioxidant and stress-related genes of P. oceanica in the vicinity of submerged volcanic vents located in the islands of Ischia and Panarea, Italy, and compared them with those from control sites away from the influence of vents. Reverse-transcription quantitative polymerase chain reaction (RT-qPCR) was used to characterize gene expression patterns. Fifty-one percent of genes analyzed showed significant expression changes. Metal detoxification genes were mostly down-regulated in relation to controls at both Ischia and Panarea, indicating that P. oceanica does not increase the synthesis of heavy metal detoxification proteins in response to the environmental conditions present at the two vents. The up-regulation of genes involved in the free radical detoxification response (e.g., CAPX, SODCP and GR) indicates that, in contrast with Ischia, P. oceanica at the Panarea site faces stressors that result in the production of reactive oxygen species, triggering antioxidant responses. In addition, heat shock proteins were also activated at Panarea and not at Ischia. These proteins are activated to adjust stress-accumulated misfolded proteins and prevent their aggregation as a response to some stressors, not necessarily high temperature. This is the first study analyzing the expression of target genes in marine plants living near natural CO2 vents. Our results call for contention to the general claim of seagrasses as "winners" in a high-CO2 world, based on observations near volcanic vents. Careful consideration of factors that are at play in natural vents sites other than CO2 and acidification is required. This study also constitutes a first step for using stress-related genes as indicators of environmental pressures in a changing ocean.
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Brinkman, T. J., und A. M. Smith. „Effect of climate change on crustose coralline algae at a temperate vent site, White Island, New Zealand“. Marine and Freshwater Research 66, Nr. 4 (2015): 360. http://dx.doi.org/10.1071/mf14077.
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Natural CO2 vents allow study of the effects of climate change on marine organisms on a different scale from laboratory-based studies. This study outlines a preliminary investigation into the suitability of natural CO2 vents near White Island, Bay of Plenty, New Zealand (37°31.19′S, 117°10.85′E) for climate change research by characterising water chemistry from two vent and three control locations on a seasonal basis, as well as examining their effects on skeletons of the local calcifying crustose coralline algae. pH measurements at vent sites, calculated from dissolved inorganic carbon and alkalinity, showed reduced mean pH levels (7.49 and 7.85) relative to background levels of 8.06, whereas mean temperatures were between 0.0 and 0.4°C above control. Increases in sulfur and mercury at sites near White Island were probably a result of volcanic unrest. Crustose coralline algae did not show significant variability in skeletal Mg-calcite geochemistry, but qualitative comparisons of calcite skeletons under scanning electron microscopy saw greater deformation and dissolution in coralline algae calcite crystals from vent sites compared to controls. Although additional monitoring of pH fluctuations and hydrogen sulphides is still needed, the low pH and increased temperatures indicate potential for studying multistressor effects of projected climate changes in a natural environment.
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de Beer, D., M. Haeckel, J. Neumann, G. Wegener, F. Inagaki und A. Boetius. „Saturated CO<sub>2</sub> inhibits microbial processes in CO<sub>2</sub>-vented deep-sea sediments“. Biogeosciences 10, Nr. 8 (26.08.2013): 5639–49. http://dx.doi.org/10.5194/bg-10-5639-2013.
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Abstract. This study focused on biogeochemical processes and microbial activity in sediments of a natural deep-sea CO2 seepage area (Yonaguni Knoll IV hydrothermal system, Japan). The aim was to assess the influence of the geochemical conditions occurring in highly acidic and CO2 saturated sediments on sulfate reduction (SR) and anaerobic methane oxidation (AOM). Porewater chemistry was investigated from retrieved sediment cores and in situ by microsensor profiling. The sites sampled around a sediment-hosted hydrothermal CO2 vent were very heterogeneous in porewater chemistry, indicating a complex leakage pattern. Near the vents, droplets of liquid CO2 were observed emanating from the sediments, and the pH reached approximately 4.5 in a sediment depth > 6 cm, as determined in situ by microsensors. Methane and sulfate co-occurred in most sediment samples from the vicinity of the vents down to a depth of 3 m. However, SR and AOM were restricted to the upper 7–15 cm below seafloor, although neither temperature, low pH, nor the availability of methane and sulfate could be limiting microbial activity. We argue that the extremely high subsurface concentrations of dissolved CO2 (1000–1700 mM), which disrupt the cellular pH homeostasis, and lead to end-product inhibition. This limits life to the surface sediment horizons above the liquid CO2 phase, where less extreme conditions prevail. Our results may have to be taken into consideration in assessing the consequences of deep-sea CO2 sequestration on benthic element cycling and on the local ecosystem state.
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Rezanejadzanjani, Behdad, und Paul G. O’Brien. „EVALUATION OF SMART BOOSTER FANS AND DAMPERS FOR ADVANCED HVAC SYSTEMS“. Journal of Green Building 16, Nr. 2 (01.03.2021): 115–27. http://dx.doi.org/10.3992/jgb.16.2.115.
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ABSTRACT There is potential to significantly reduce CO2 emissions by increasing the efficiency and reducing the duty cycle of HVAC systems by using smart booster fans and dampers. Smart booster fans fit in the vents within a home, operating quietly on low power (2W) to augment HVAC systems and improve their performance. In this study, a prototype duct system is used to measure and evaluate the ability for smart booster fans and dampers to control airflow to different vents for the purpose of increasing the efficiency of HVAC systems. Four case studies were evaluated: an HVAC system (1) without any fans or dampers, (2) with a fan installed in one vent, but without any dampers, (3) with dampers installed at the vents, but without any fans, and (4) with both fan and dampers installed. The results from both the experimental and numerical evaluation show that the smart booster fan and dampers can significantly improve the airflow at a vent that is underperforming. For example, the airflow at the last vent in a ducting branch was increased from 17 to 37 CFM when a smart booster fan was installed at this vent. Results from the numerical analysis show that for the case of an underperforming vent during the winter season the HVAC running time may be reduced from 24 hr/day to 5.6 hr/day. Furthermore, results from the numerical analysis show the HVAC running time is further reduced to 4.5 hr/day for cases 3 and 4.
Dissertationen zum Thema "CO2 vents"
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Parrella, Penelope. „Temporal dynamics of benthic assemblages along a gradient of ocean acidification at a CO2 vent’s system of the Ischia Island“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10063/.
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Global warming and ocean acidification, due to rising atmospheric levels of CO2, represent an actual threat to terrestrial and marine environments. Since Industrial Revolution, in less of 250 years, pH of surface seawater decreased on average of 0.1 unit, and is expected to further decreases of approximately 0.3-0.4 units by the end of this century. Naturally acidified marine areas, such as CO2 vent systems at the Ischia Island, allow to study acclimatation and adaptation of individual species as well as the structure of communities, and ecosystems to OA.
The main aim of this thesis was to study how hard bottom sublittoral benthic assemblages changed trough time along a pH gradient. For this purpose, the temporal dynamics of mature assemblages established on artificial substrates (volcanic tiles) over a 3 year- period were analysed.
Our results revealed how composition and dynamics of the community were altered and highly simplified at different level of seawater acidification. In fact, extreme low values of pH (approximately 6.9), affected strongly the assemblages, reducing diversity both in terms of taxa and functional groups, respect to lower acidification levels (mean pH 7.8) and ambient conditions (8.1 unit). Temporal variation was observed in terms of species composition but not in functional groups. Variability was related to species belonging to the same functional group, suggesting the occurrence of functional redundancy. Therefore, the analysis of functional groups kept information on the structure, but lost information on species diversity and dynamics.
Decreasing in ocean pH is only one of many future global changes that will occur at the end of this century (increase of ocean temperature, sea level rise, eutrophication etc.). The interaction between these factors and OA could exacerbate the community and ecosystem effects showed by this thesis.
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Mangiapia, Mary Ann. „From CO2 to Cell: Energetic Expense of Creating Biomass Using the Calvin-Benson-Bassham and Reductive Citric Acid Cycles Based on Genomic Data“. Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5264.
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Abstract
The ubiquity of the Calvin-Benson-Bassham cycle (CBB) amongst autotrophic organisms suggests that it provides an advantage over a wide range of environmental conditions. However, in some habitats, such as hydrothermal vents, the reductive citric acid cycle (rCAC) is an equally predominant carbon fixation pathway. It has been suggested that the CBB cycle poses a disadvantage under certain circumstances due to being more energetically demanding compared to other carbon fixation pathways. The purpose of this study was to compare the relative metabolic cost of cell biosynthesis by an autotrophic cell using either the CBB cycle or the rCAC. For both pathways, the energy, in ATP, required to synthesize the macromolecules (DNA, RNA, protein, and cell envelope) for one gram of biomass was calculated, beginning with CO2. Two sulfur-oxidizing chemolithoautotrophic proteobacteria, Thiomicrospira crunogena XCL-2, and Sulfurimonas autotrophica were used to model the CBB cycle and rCAC, respectively while Escherichia coli was used to model both pathways because it has had its cell composition extremely well-characterized. Since these organisms have had their genomes sequenced, it was possible to reconstruct the biochemical pathways necessary for intermediate and macromolecule synthesis. Prior estimates, based solely on the ATP cost of pyruvate biosynthesis, suggested that the cellular energetic expense for biosynthesis from the CBB cycle was more than that from the rCAC. The results of this study support this conclusion; however the difference in expense between the two pathways may not be as extreme as suggested by pyruvate synthesis. Other factors, such as oxygen sensitivity, may act in concert with energetic expense in contributing to the selective advantages between different autotrophic carbon fixation pathways.
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Carbonne, Chloé. „Role of environmental variability on the response of Mediterranean corals to global change“. Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS531.
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L’augmentation du CO2 atmosphérique conduit à des changements physiques et chimiques de l’océan. Les projections du GIEC selon le scénario à fortes émissions RCP8.5, suggèrent un réchauffement de la surface des océans de 3.2°C et une diminution de 0.3 unités de pH à la fin du siècle. Ces changements environnementaux s’accompagnent d’importantes conséquences sur les écosystèmes et les services rendus aux humains. La mer Méditerranée est un « hotspot » du changement global avec une prévision d’augmentation de la température de surface de la mer de +20% comparé aux projections globales, accompagné d’une augmentation d'événements extrêmes comme les vagues de chaleur marines. L’objectif principal de cette thèse est de déterminer les effets de la variabilité environnementale présente et future sur des coraux Méditerranéens. Des populations naturelles de coraux vivant au niveau d’évents de CO2 à Ischia (Italie) sont utilisées. Une acidification locale de l’eau de mer survient autour de ces évents, avec des valeurs de pH proches de celles qui sont attendues pour la fin du siècle. Les deux espèces étudiées : Cladocora caespitosa (zooxanthellé) et Astroides calycularis (azooxanthellé), ont une grande importance pour la conservation de part leur statut d’espèces fondatrices. Les principales questions de l’étude sont: (1) comment les conditions présentes et futures de températures et/ou de pH affectent la physiologie des deux espèces à différents stades de vie (adultes, gamétogenèse, larves et recrues) et (2) est-ce que l’exposition à un pH bas peut augmenter la tolérance des coraux face à une future acidification. Afin de répondre à ces questions, nous avons combiné l’analyse de données environnementales, l’étude sur le terrain et des expériences de laboratoire avec contrôle de température et de pH. Ma thèse se focalise en premier lieu sur la réponse des colonies adultes face au réchauffement de l’océan, avec l’acquisition des réponses physiologiques et le rétablissement des deux coraux à un réchauffement et à des vagues de chaleur marines simulées en laboratoire à partir de données réelles. Nous avons ensuite étudié, si l’exposition au pH bas des évents de CO2 procurait une tolérance à l’acidification chez les deux espèces. Cette thèse s’applique également à identifier l’impact du changement global sur la reproduction sexuelle et les premiers stades de vie des deux espèces de coraux. Dans un premier temps, j’ai étudié le développement et la croissance post fixation de larves d’A. calycularis face au réchauffement et à l’acidification. Puis, j’ai testé l’hypothèse selon laquelle des larves provenant des évents de CO2 présentaient une tolérance à l’acidification. L’expression des gènes entre les populations et les traitements de pH en laboratoire a également été étudiée. Enfin, une comparaison des gamètes de C. caespitosa provenant des évents de CO2 et d’un site ambient a été effectuée par analyse histologique afin de savoir si le pH a un impact sur la gamétogenèse et le ponte. Nos résultats suggèrent que les impacts du réchauffement et de l’acidification sur les colonies adultes de C. caespitosa et A. calycularis sont modérées, avec une tolérance à l’acidification et un rétablissement après les températures estivales. Par contre, l’impact sur les premiers stades de vie d’A. calycularis et la reproduction de C. caespitosa est inquiétant et pourrait compromettre le maintien des populations. Mes résultats suggèrent que C. caespitosa and A. calycularis vivants au niveau des évents de CO2 de Ischia, ne sont pas acclimatés à l’acidification de l’eau de mer. De plus, cette exposition à des pH bas affecterait la physiologie des individus et la croissance de la population. Étant donné la sensibilité des deux espèces de coraux au changement global, ma thèse souligne un risque de changement de composition des communautés méditerranéennes dans un futur proche et une urgence à établir des mesures de conservation et un suivi à long termeThe increase of atmospheric CO2 is driving changes in the ocean’s physical and chemical properties. The projections by the IPCC under the high CO2 emission scenario RCP 8.5 suggest global sea surface temperature warming of 3.2°C and a decrease in pH of 0.3 units by the end of the century. Such changes have important consequences for ecosystems and the services they provide to humans. The Mediterranean Sea is a hot-spot of global change with warming sea surface temperature projected to be 20% higher than global projections and an increase in extreme events such as marine heatwaves. The main goal of this thesis is to determine the effects of present and future coastal environmental conditions on Mediterranean corals. Natural populations of corals from two volcanic CO2 vents in Ischia (Italy) are used. Local acidification of seawater occurs around the vents with pH values close to those expected by the end of the century. This research is focused on two Mediterranean long-lived corals that have key relevance for conservation as habitat-forming species: the zooxanthellate Cladocora caespitosa and the azooxanthellate Astroides calycularis. The main research questions are: (1) how present-day and future warming and/or acidification affect the physiology of Cladocora caespitosa and Astroides calycularis at every life stage (adult, gametogenesis, larvae, and recruits) and (2) does previous exposure to low pH at CO2 vents enhance their tolerance to future ocean acidification. To answer these questions, we combined environmental data, ecological field surveys at CO2 vent sites and reference sites with ambient pH, and laboratory experiments with controlled temperature and pH. This thesis provides new insights into the responses of adult colonies to warming on. I assess the physiological impact and potential recovery to different warming scenarios and heatwaves events, based on nine years of temperature data collected at the study site. I then study whether past exposure to low pH conditions confers tolerance to ocean acidification on the two species, with colonies sampled at the CO2 vent and ambient pH sites and maintained in the laboratory under present day and low pH conditions. I also focus on sexual reproduction and early life stages of the two Mediterranean corals to better understand how they respond to ocean warming and acidification. First, I characterize the development and post-settlement growth of larvae of A. calycularis under high and ambient temperatures and ambient and low pH. I then take a closer look at tolerance to acidification by exposing larvae from the CO2 vents and ambient pH site to different pH conditions. I also explore whether differences in gene expression between the populations and pH treatments exist. Finally, I compare gametogenesis of C. caespitosa’s colonies from the CO2 vent and ambient sites through histological analysis to test the impact of low pH on gametogenesis and spawning. The results suggest that the impacts of warming and acidification on adult colonies of C. caespitosa and A. calycularis are moderate, with a tolerance to acidification and a recovery after summer heat. However, the impact of global change on the early life stages of A. calycularis and on the reproduction of C. caespitosa is worrying and could compromise the sustainability of the populations. My results suggest that C. caespitosa and A. calycularis living at the CO2 vents sites of Ischia are not acclimatized to ocean acidification. Furthermore, exposure to low pH at the vent sites impairs individuals’ physiology (reproduction, early life stages development, morphology of the colony) and population growth. Given the susceptibility of both species to global change, the results highlight the risk of changes in the composition of Mediterranean communities in the near future and the urge to establish general conservation measures and long-term monitoring
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Sornig, Manuela. „Investigations of upper atmosphere dynamics on Mars and Venus by high resolution infrared heterodyne spectroscopy of CO2“. Göttingen Cuvillier, 2009. http://d-nb.info/992626366/04.
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Sforna, Claudia. „Relazioni fra regime dei venti e pH in un "campo di fumarole" a CO2 sui fondali costieri dell'isola d'Ischia (Italy)“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9630/.
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Il problema dell'acidificazione degli oceani, conseguente ai cambiamenti climatici, è un processo ancora poco conosciuto. Per comprendere questo fenomeno, possono essere utilizzati degli ambienti naturalmente acidificati, considerati laboratori a cielo aperto.
Lo scopo di questo lavoro di tesi è stato quello di utilizzare le fumarole presenti nell'isola di Ischia, per approfondire le dinamiche dei processi di acidificazione e per analizzare l'eventuale interazione tra pH e condizioni meteorologiche.
I dati utilizzati, forniti dalla Stazione Zoologica “Anton Dohrn” di Napoli, erano serie di pH e di vento rilevate in continuo, in due aree, nord e sud rispetto all'isolotto del Castello Aragonese, e in tre stazioni lungo un gradiente di acidificazione. Tutto il lavoro è stato svolto a step, dove il risultato di un'analisi suggeriva il tipo e il metodo analitico da utilizzare nelle analisi successive. Inizialmente i dati delle due serie sono stati analizzati singolarmente per ottenere i parametri più salienti delle due serie. In seguito i dati sono stati correlati fra loro per stimare l'influenza del vento sul pH.
Globalmente è stato possibile evidenziare come il fenomeno dell'acidificazione sia correlato con il vento, ma la risposta sembra essere sito-specifica, essendo risultato dipendente da altri fattori interagenti a scala locale, come la geomorfologia del territorio, le correnti marine e la batimetria del fondale. È però emersa anche la difficoltà nel trovare chiare correlazioni fra le due serie indagate, perché molto complesse, a causa sia della numerosa quantità di zeri nella serie del vento, sia da una forte variabilità naturale del pH, nelle varie stazioni esaminate.
In generale, con questo lavoro si è dimostrato come utilizzare tecniche di analisi delle serie storiche, e come poter utilizzare metodi di regressione, autocorrelazione, cross-correlation e smoothing che possono integrare i modelli che prendono in considerazione variabili esogene rispetto alla variabile di interesse.
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Sokolov, Andrei V. „Description Non-Markovienne de formes spectrales large-bandes : application au cas de diffusion Raman par N2/CO2 et lien avec la modélisation de l'atmosphère de Venus“. Thesis, Bourgogne Franche-Comté, 2020. http://www.theses.fr/2020UBFCD055.
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Ce travail est une des premières tentatives d’utiliser une théorie non-Markovienne Energy- and Frequency-Corrected Sudden Approximation (EFCSA) pour construire la matrice de relaxation rotationnelle et modéliser des formes de bandes spectrales de gaz atmosphériques à haute pression. Nous avons généralisé les expressions déjà existantes pour la matrice de relaxation non-Markovienne pour le cas de deux molécules linéaires, ainsi prenant en compte la structure interne du perturbateur. Cette prise en compte est fondamentale pour une meilleure description des ailes spectrales lointaines, ce qui est essentiel pour la modélisation du transfert radiatif dans des milieux denses et dans l’atmosphère de Venus en particulier. Pour calculer cette matrice, il suffit de connaitre les fonctions de corrélation temporelles liées au mouvement translationnel, et nous proposons deux pistes directes pour les obtenir. La première utilise l’approche des moments spectraux. Nous avons obtenu des expressions analytiques pour les moments d’ordre 0 et 2 et testé la méthode sur des spectres Ramanroto-translationnels de N2 et CO2 purs. La seconde approche est basée sur le modèle Energy-Corrected Sudden (ECS). Nous avons donné des expressions qui prennent en compte la structure interne de la molécule perturbatrice et nous avons présenté un jeu de paramètres qui peuvent être ajustés surd es largeurs de raie expérimentales et utilisés par la suite pour calculer des spectres de gaz atmosphériques, y compris des spectres d’absorption de dioxyde de carbone à haute pression et haute températureThis work presents one of the first attempts in using a non-Markovian Energy- and Frequency-Corrected Sudden Approximation (EFCSA) to build a rotational relaxation matrix and model spectral band shapes of atmospheric gases at highpressure. We have extended the existing expressionsfor the non-Markovian relaxation matrix to the case of two linear colliders, thus taking into account the internal structure of the perturber. This account is instrumental in a better description of the far spectral wings, which is essential for simulating the radiative transfer in dense media and, in particular, modeling of the Venus atmosphere. For the calculation of the matrix, it is sufficient to know translational time-correlation unctions, and we propose two straight forward ways to obtain them. The first one uses the spectral-moments approach. We have obtained analytical expressions for the 0th and 2nd moments and tested the approach forroto-translational Raman spectra of pure N2and CO2. The second approach is based onthe Energy-Corrected Sudden (ECS) model.We have outlined the expressions involving the second linear molecule and presented sets of parameters, which can be fitted on the experimental line widths and later used to predict the spectra of atmospheric species,including the absorption spectra of carbondioxide at high pressure and temperature
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Faustino, Rui Miguel Gaspar. „Avaliação do potencial eólico da zona de Évora - Contribuição para a redução de emissões de CO2“. Master's thesis, Universidade de Évora, 2009. http://hdl.handle.net/10174/18585.
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Neste trabalho é analisado o potencial eólico da região de Évora, tendo sido considerados quatro locais: Mitra, Portel, Reguengos e Colégio Verney. Com os dados de potência obtidos, foram escolhidas duas turbinas existentes no mercado, de potências nominais diferentes, para uma análise mais objectiva do real potencial da região. Apurou-se que, com a instalação de três turbinas menores, se obtém praticamente a mesma potência, por um preço consideravelmente inferior. Foi ainda possível verificar-se que a quantidade evitada de C02 para a atmosfera, ao considerar uma turbina de 5000 W (B) ou três 1000 W (A), é semelhante, concluindo-se que, considerando a eficiência, potencial, preço e emissões de co2 evitadas, a instalação de diversas turbinas A é a melhor opção. Este trabalho reveste-se de particular interesse considerando o facto de ser do conhecimento geral que, nas regiões costeiras e montanhosas, o potencial eólico está bastante estudado, ao passo que nas regiões interiores tal não acontece. ABSTRACT: ln this work, we assess the potential wind power in Évora, and four locations have been considered: Mitra, Portel, Reguengos and Évora. Based on the local wind power potential, two kinds of turbines were selected, for a more objective analysis of the region's useful wind power. It was found that the option for three small turbines allows the extraction of the same wind power that is extracted by the bigger turbine and at a considerably lower installation cost. lt was also found that the reduction in co2 emissions to the atmosphere, when considering the cases of one 5000 W (B) turbine and three 1000 W (A) turbines, is similar, therefore was concluded that, given the efficiency, potential, price and reduction of C02 emissions, the installation of several A turbines is the best option. This work is of particular interest because in coastal and mountain areas the wind potential is quite known, while this is not the case of inland areas.
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Stangier, Tobias [Verfasser]. „Atmospheric Thermal Properties of Venus and Mars - Investigation of CO2 Absorption Lines using Ground-Based Mid-Infrared Heterodyne Spectroscopy / Tobias Stangier“. München : Verlag Dr. Hut, 2015. http://d-nb.info/1067708030/34.
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Krause, Pia [Verfasser]. „Upper Atmospheric Thermal Properties of Venus - Investigation of non-LTE CO2 Emission Lines using Ground-Based Mid-Infrared Heterodyne Spectroscopy / Pia Krause“. München : Verlag Dr. Hut, 2021. http://d-nb.info/1232847267/34.
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Granero-Fernandez, Emanuel. „Fluides supercritiques et solvants biosourcés : propriétés physicochimiques des systèmes expansés par du CO2“. Thesis, Toulouse, INPT, 2018. http://oatao.univ-toulouse.fr/23928/1/Granero%20Fernandez_Emanuel.pdf.
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Les objectifs environnementaux (COP21) visant à réduire les émissions de gaz à effet de serre et l'impact de l'industrie sur la nature, font face au défi de la demande croissante d'énergie et de produits. Les procédés chimiques sont les premiers en cause lorsqu’ils mettent en œuvre des solvants. L'ingénierie des solvants est une solution innovante qui vise à trouver des milieux alternatifs bénins possédant les propriétés de solvant adaptés pour chaque étape du procédé.Dans cette perspective, nous avons étudié les Liquides expansés par un gaz (LEGs), qui sont desliquides dont le volume augmente sous l’effet d’un gaz dissous sous pression. En particulier, le CO2 peut être utilisé comme agent d'expansion pour obtenir des liquides expansés par du CO2(LECs), combinant les avantages du CO2 et du solvant. La phase expansée peut contenir des concentrations élevées de CO2, jusqu'à 80%, selon le solvant, ce qui conduit à une réduction du besoin du solvant organique, mais aussi à des changements des propriétés physicochimiques et de transport de la nouvelle phase expansée. On peut de plus moduler ces propriétés par la pression et la température, d'une manière réversible, et améliorer la séparation des produits. Dans cette étude, différents solvants biosourcés ont été utilisés pour obtenir des systèmes expansés par du CO2, tels que les acétates d'alkyle, les carbonates organiques, les méthoxybenzènes, etc.La connaissance des équilibres de phase, des propriétés de solvatation et de transport est essentielle pour concevoir des processus qui exploitent le comportement particulier de ces systèmes biphasiques. Deux approches principales ont été utilisées pour caractériser ces systèmes. Dans un premier temps, des mesures ont été effectuées dans une cellule à haute pression et à volume variable pour évaluer la polarité au travers du paramètre Kamlet-Taft (KT) *(dipolarité / polarisabilité) dans les solvants expansés par du CO2 sous des pressions allant jusqu'à 30 MPa. La technique utilisée a été la spectroscopie UV-Vis suivant le déplacement hypsochromique du Rouge de Nile, une sonde solvatochromique déjà utilisée pour obtenir les paramètres KT dans des solvants purs. De plus, des mesures d'équilibre vapeur-liquide (ELV) ont été effectuées pour obtenir la composition de la phase expansée à différentes pressions et températures afin de comprendre la solvatation du CO2 dans les solvants organiques et de fournir des informations manquantes dans la littérature. En deuxième lieu, dans une approche plus théorique, les données ELV ont été utilisées pour calculer numériquement d'autres propriétés telles que la densité et la viscosité. Des équations d'état et des simulations par dynamique moléculaire (DM) ont été utilisées ; ces dernières donnant de meilleurs résultats dans un mode prédictif de la masse volumique et permettant de suivre les positions moléculaires au cours du temps, qui peut être liée à de nombreuses propriétés, y compris la viscosité étudiée ici. Ces calculs ont été effectués en utilisant un champ de force de type Amber adapté. Les résultats obtenus dans l’ensemble complètent les données de la littérature existante et apportent de nouvelles informations sur les propriétés des LEGs. Par exemple, le comportement non linéaire de l'expansion volumétrique, vérifié après les déterminations de masse volumique sur les simulations DM à l'équilibre, est une clé dans la compréhension des interactions soluté-solvant ; ainsi que les valeurs KT * obtenues qui confirment la large gamme de polarité couverte par ces systèmes.Enfin, certains systèmes expansés par du CO2 ont été utilisés pour produire des nanoparticules de TiO2 pour panneaux solaires, améliorant leur surface spécifique et donc leur efficacité en tant que semi-conducteurs ; et d’autres ont été appliqués à un processus d'activation enzymatique entraînant une augmentation significative du taux de conversion
Bücher zum Thema "CO2 vents"
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Ojer, Laura. Esquina con Venus. Lleida: Edicions de la Universitat de Lleida, 1994.
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Tusceri, Gian Carlo. Parlavo col vento. La Maddalena (Sassari): P. Sorba, 2006.
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Margaret, Mitchell. Via col vento. Milano: Mondadori, 2010.
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Sensini, Alessandra. Una vita con il vento. Milano: Longanesi, 2010.
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Via col vento in Vaticano. Milano: Kaos, 1999.
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Cristalli, Paola. Victor Fleming: Via col vento. Torino: Lindau, 2001.
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Piccinelli, Franco. Con le radici al vento. Ivrea (To): Priuli & Verlucca, 2002.
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Piqué, Joan Graell i. Un llapis com el vent. Tremp [Spain]: Garsineu Edicions, 1997.
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Calisto, Rosa. De mãos dadas com o vento. Lisboa: Chiado, 2011.
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Herrera, Jorge Eliécer Prieto. Las ventas: Una profesión para gente superior : cómo aprender a vender con éxito. Bogotá: ECOE Ediciones, 2000.
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Miglietta, F., M. Badiani, I. Bettarini, P. van Gardingen, F. Selvi und A. Raschi. „Preliminary Studies of the Long-Term CO2 Response of Mediterranean Vegetation Around Natural CO2 Vents“. In Global Change and Mediterranean-Type Ecosystems, 102–20. New York, NY: Springer New York, 1995. http://dx.doi.org/10.1007/978-1-4612-4186-7_5.
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D’Ambrosio, Antonio. „«Una diversa me stessa». Venti racconti di Gianna Manzini“. In Studi e ricerche del Dipartimento di Lettere e Filosofia, 393–413. Firenze: Società Editrice Fiorentina, 2023. http://dx.doi.org/10.35948/dilef/978-88-6032-688-1.22.
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L’intervento presenta l’evoluzione della narrativa di Gianna Manzini dall’esordio con Tempo innamorato (1928) fino a Venti racconti (1941), antologia che riassume il suo intero percorso creativo. Di questa indaga la storia, attraverso il carteggio con Giuseppe De Robertis; studia la struttura; dimostra la raggiunta maturità stilistica dell’autrice con l’analisi di un campionario di varianti.
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Bradbeer, Mark. „Venus and Adonis and Two Noble Kinsmen“. In Aemilia Lanyer as Shakespeare's Co-Author, 181–96. London: Routledge, 2022. http://dx.doi.org/10.4324/9781003221203-22.
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Azzetta, Luca. „Iniziative per un centenario. Dante al Dipartimento di Lettere e Filosofia“. In L'illustre volgare, 21–33. Firenze: Società Editrice Fiorentina, 2022. http://dx.doi.org/10.35948/dilef/978-88-6032-685-0.02.
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Il contributo presenta le iniziative maturate all’interno del Dipartimento di Lettere e Filosofia dell’Università di Firenze in occasione del settimo centenario della morte di Dante. In particolare si sofferma su due iniziative: dapprima l’ampio ciclo di conferenze Dante e i poeti italiani del Novecento, dedicato al vario rapporto intrattenuto da venti poetesse e poeti del secolo scorso con la poesia dell’Alighieri; quindi la mostra Onorevole e antico cittadino di Firenze. Il Bargello per Dante, ospitata nelle sale del Museo del Bargello, che ricostruisce le modalità con cui Firenze, pochi anni dopo la morte di Dante, si riappropriò della memoria e della figura del poeta, dando vita a un profondo processo di rielaborazione della memoria: esso culmina con la consacrazione dell’Alighieri dovuta a Giovanni Boccaccio e ha ricadute decisive per la storia della letteratura e della cultura italiana, cioè del modo in cui ancora oggi si guarda a Dante e si legge la Commedia. All’interno di questo percorso di riappropriazione un aspetto rilevante è quello che riguarda le prime traduzioni dai classici latini, che intrattengono con la Commedia un rapporto privilegiato e complesso.
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Berner, Robert A. „Processes of the Long-Term Carbon Cycle: Degassing of Carbon Dioxide and Methane“. In The Phanerozoic Carbon Cycle. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780195173338.003.0006.
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Degassing of CO2 and CH4 to the atmosphere and oceans is the process whereby carbon is restored to the surficial system after being buried in rocks. Carbon dioxide is released by a variety of processes. This includes volcanic emissions from the mantle and metamorphic and diagenetic decarbonation of limestones and organic matter. Volcanic degassing can occur over subduction zones, at mid-ocean rises, on the continents, and in the interior of oceanic plates. Degassing can be sudden and violent, as during volcanic eruptions, or slow and semi-continuous in the form of fumaroles, springs, gas vents, and continually degassing volcanic vents. An outstanding example of the latter is Mt. Etna, which contributes about 10% to total global degassing (Caldeira and Rampino, 1992). Metamorphic degassing is concentrated in zones of seafloor subduction (Barnes et al., 1978), crustal convergence (Kerrick and Caldeira, 1998), and crustal extension (Kerrick et al., 1995). Most methane degassing on a geologic time scale occurs from organic matter diagenesis slowly from coal, oil, and kerogen maturation and suddenly from methane hydrate breakdown. A smaller amount of CH4 emanates from mid-ocean hydrothermal vents. Estimates of present-day global volcanic degassing rates are under constant revision (e.g., see Gerlach, 1991; Brantley and Koepenick, 1995; Sano and Williams, 1996; Marty and Tolstikhin, 1998; Kerrick, 2001). A compilation of recent estimated rates of most degassing processes is shown in table 4.1. A constraint on estimates is that none can exceed total global degassing. The latter can be determined from the steady-state assumption that CO2 release by global degassing must be balanced by global uptake by Ca and Mg silicate weathering (Berner, 1990; Berner and Caldeira, 1997). (This assumes essential balance of the organic C subcycle.) Global Ca and Mg silicate weathering, based on river fluxes of these elements to the sea, has been estimated to be about 6 ± 3 × 1018 mol/my (Berner, 1990). Gaillardet et al. (1999) estimate a minimum value for Ca and Mg silicate weathering of 3.6 × 1018 mol/my.
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Marques, Marcelo, Fernando Oliveira de Andrade, Elaine Patricia Arantes und Cristhiane Michiko Passos Okawa. „SIMULAÇÃO NUMÉRICA DOS CAMPOS DE ONDAS GERADAS POR VENTOS SEVEROS NO RESERVATÓRIO DE JURUMIRIM“. In Avanços em Computação Aplicada a Fluidodinâmica Computacional, 23–32. Bookerfield Editora, 2021. http://dx.doi.org/10.53268/bkf21120502.
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A simulação da distribuição espacial das ondas geradas pela ação de ventos severos sobre o reservatório da barragem de Jurumirim se constitui no objetivo desse trabalho. Por situarem-se próximos à divisa com o Estado do Paraná, os ventos severos foram estimados através da análise de frequência regional de dados provenientes das estações anemométricas do Instituto Meteorológico do Paraná (SIMEPAR). A análise considerou os registros horários das rajadas medidas nas estações do SIMEPAR para o período de 1998 a 2005. Os testes estatísticos produziram estimativas de ventos severos que variaram entre 14,6 ms-1 (período de retorno de 10 anos) a 27,6 ms-1 (período de retorno de 100 anos). As alturas de ondas foram simuladas com base em uma equação paramétrica concebida especificamente para esse reservatório pela aplicação da técnica de modelagem Paramétrica Bidimensional. Por essa técnica, a altura da onda é condicionada exclusivamente por informações de vento (intensidade e direção) e o comprimento do fetch no ponto de interesse. A técnica de modelagem foi aplicada pelo modelo computacional ONDACAD. As maiores alturas de onda resultaram de ventos severos provenientes da direção WNW, produzindo ondas de alturas correspondentes a 1,16m (Tr=10 anos), 1,41m (Tr=20 anos), 1,97m (Tr=50 anos) e 2,67m (Tr=100 anos).
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Andersson, Andreas J., und Fred T. Mackenzie. „Effects of Ocean Acidification on Benthic Processes, Organisms, and Ecosystems“. In Ocean Acidification. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199591091.003.0012.
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The benthic environment refers to the region defined by the interface between a body of water and the bottom substrate, including the upper part of the sediments, regardless of the depth and geographical location. Hence, benthic environments, their organisms, and their ecosystems are highly variable as they encompass the full depth range of the oceans with associated changes in physical and chemical properties as well as differences linked to latitudinal and geographical variation. The effects of ocean acidification on the full range of different benthic organisms and ecosystems are poorly known and difficult to ascertain. Nevertheless, by integrating our current knowledge on the effects of ocean acidification on major benthic biogeochemical processes, individual benthic organisms, and observed characteristics of benthic environments as a function of seawater carbonate chemistry, it is possible to draw conclusions regarding the response of benthic organisms and ecosystems to a world of increasingly higher atmospheric CO2 levels. The fact that there are large-scale geographical and spatial differences in seawater carbonate system chemistry (see Chapter 3), owing to both natural and anthropogenic processes, provides a powerful means to evaluate the effect of ocean acidification on marine benthic systems. In addition, there are local and regional environments that experience high-CO2 and low-pH conditions owing to special circumstances such as, for example, volcanic vents (Hall- Spencer et al . 2008 ; Martin et al . 2008 ; Rodolfo-Metalpa et al . 2010), seasonal stratification (Andersson et al . 2007), and upwelling (Feely et al . 2008 ; Manzello et al . 2008 ) that may provide important clues to the impacts of ocean acidification on benthic processes, organisms, and ecosystems. The objective of this chapter is to provide an overview of the potential consequences of ocean acidification on marine benthic organisms, communities, and ecosystems, and the major biogeochemical processes governing the cycling of carbon in the marine benthic environment, including primary production, respiration, calcification, and CaCO3 dissolution. The depth of the euphotic zone, i.e. the depth of water exposed to sufficient sunlight to support photosynthesis, varies depending on a range of factors affecting the clarity of seawater, including river input and run-off to the coastal ocean, upwelling, mixing, and planktonic production.
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Marques, Marcelo, Elaine Patricia Arantes, Fernando Oliveira de Andrade und Isabela Arantes Ferreira. „SIMULAÇÃO COMPUTACIONAL DOS CAMPOS DE ENERGIA DE ONDAS EM RESERVATÓRIO DE USINA HIDRELÉTRICA“. In Aplicações Avançadas de Simulação Computacional, 100–106. Bookerfield Editora, 2021. http://dx.doi.org/10.53268/bkf21060407.
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A simulação da distribuição espacial da energia das ondas geradas pela ação de ventos severos sobre o reservatório de belo Monte se constitui no objetivo desse trabalho. Os campos de energia das ondas foram simulados com base em uma equação obtida pela combinação de uma equação paramétrica denominada JONSWAP e da equação de energia fundamentada no conhecimento de mecânica das ondas. Pela técnica empregada denominada Paramétrica Bidimensional, a energia da onda é condicionada exclusivamente por informações de vento (intensidade e direção) e o comprimento do fetch no ponto de interesse. A técnica de modelagem foi aplicada pelo modelo computacional ONDACAD. As maiores quantidades de energia de onda resultaram de ventos provenientes da direção NNE, de energia correspondente a 82 J/m2 (U=5ms-1); 375 J/m2 (U=10ms-1); 1020 J/m2 (U=15ms-1) e 1610 J/m2 (U=20ms-1).
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Marques, Marcelo, Alejandro Victor Hidalgo Valdivia, Fernando Oliveira de Andrade, Elaine Patricia Arantes und Isabela Arantes Ferreira. „ANÁLISE HIDRODINÂMICA DOS CAMPOS DE ENERGIA DAS ONDAS GERADAS PELO VENTO NO RESERVATÓRIO DE TUCURUÍ“. In Avanços em Computação Aplicada a Fluidodinâmica Computacional, 14–22. Bookerfield Editora, 2021. http://dx.doi.org/10.53268/bkf21120501.
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A simulação da distribuição espacial da energia das ondas geradas pela ação de ventos severos sobre o reservatório de Tucuruí constitui-se no objetivo deste trabalho. Os campos de energia das ondas foram simulados com base em na combinação de uma equação paramétrica denominada JONSWAP e da equação de energia fundamentada no conhecimento de mecânica das ondas. Pela técnica empregada denominada Modelagem Paramétrica Bidimensional (MPB), a energia da onda é condicionada exclusivamente por informações de vento (intensidade e direção) e o comprimento do fetch no ponto de interesse. A técnica de modelagem foi aplicada pelo modelo computacional ONDACAD. As maiores quantidades de energia de onda resultaram de ventos provenientes das direções W e WNW, de energia correspondente a 656 J/m2 (U=5ms-1); 2624 J/m2 (U=10ms-1); 5904 J/m2 (U=15ms-1); 10496 J/m2 (U=20ms-1).
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García Gómez, Douglas Adolfo, Yamarú del Valle Chirinos Araque und Dorkys Coromoto Rojas Nieves. „Comportamiento de la gestión de ventas en empresas emprededoras del municipio Sancti Spiritus, Cuba“. In Tendencias en la investigación universitaria. Una visión desde Latinoamérica. Volumen XII, 239–57. Fondo Editorial Universitario Servando Garcés de la Universidad Politécnica Territorial de Falcón Alonso Gamero / Alianza de Investigadores Internacionales S.A.S., 2020. http://dx.doi.org/10.47212/tendencias2020vol.xii.15.
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El sector no estatal cubano hoy en día se encuentra entre las principales fuentes emergentes de la economía, de allí la importancia que reviste aumentar de forma significativa la calidad de la gestión de venta presente en las pequeñas empresas nacientes, como elemento determinante para que los emprendedores de nuevos negocios obtengan una mayor sensibilidad hacia las percepciones de los clientes y el valor de la oferta, variables imprescindibles para incrementar las tasas de éxito de estas organizaciones. La presente investigación tiene como objetivo evaluar la gestión de ventas en empresas emprendedoras del municipio de Sancti Spiritus, Cuba, para contribuir a elevar la satisfacción de los clientes.El estudio toma como muestra dos empresas, GRAFICENTRO y el restaurante ¨Piratas del Caribe¨. Para su realización se adoptó como metodología la toma de decisiones multicriterio, con una orientación cuantitativa y se aplicó el índice decalidad de la gestión de ventas. Se utilizaron métodos y técnicas como: observación directa, entrevista, entropía y AHD de Saaty, a través de los cuales se pudieron identificar los problemas existentes para derivar las posibles soluciones y se perfeccionó la satisfacción al cliente.
Konferenzberichte zum Thema "CO2 vents"
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Allason, Dan, Keith Armstrong, Julian Barnett, Phil Cleaver und Ann Halford. „Behaviour of Releases of Carbon Dioxide From Pipelines and Vents“. In 2014 10th International Pipeline Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/ipc2014-33384.
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A large Research and Development programme has been executed by National Grid to determine the feasibility of transporting carbon dioxide (CO2) by pipeline. Such pipelines would be required to form a transportation system to take the CO2 from its place of capture at an emitter’s site to a place of safe storage within a Carbon Capture and Storage (CCS) scheme. This programme received financial support from the European Union. As part of this programme, National Grid commissioned a series of experimental studies to investigate the behaviour of releases of CO2 mixtures in the gaseous and the liquid (or dense) phase. This has included simulating accidental releases in the form of punctures or ruptures of a buried pipeline and deliberate releases through different venting arrangements. This work is required, as CO2 has the potential to cause some harm to people if they are exposed to it for long enough at high concentrations. This paper gives an overview of the findings from this work and shows how the data has been used to help develop a number of the more pragmatic, predictive models for outflow and dispersion. This work complements the more theoretical studies carried out using state of the art advanced computational fluid dynamic models, employed by other UK based participants (University College London, University of Leeds, Kingston University and the University of Warwick) in the research programme.
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Hu, Qiannan, Xin Zhang, Bing Wang, Chuanbo Wang, Zhendong Luan, Changan Chen und Jun Yan. „In situ detection of CO2/CH4 dissolved in vent-associated seawater at the CLAM and Iheya North hydrothermal vents area, Okinawa Trough“. In OCEANS 2015 - Genova. IEEE, 2015. http://dx.doi.org/10.1109/oceans-genova.2015.7271436.
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Garceau, Sean, Amar Jawalkar, Ryan McKennon, Christopher Moffatt, Anthony Pocengal und Michella Thomas. „Methane Emissions Reduction Solutions: Product Development and Standardization“. In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-15758.
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Abstract The Oil & Gas industry and environmental agencies around the world are working to find solutions to reduce greenhouse gas (GHG) emissions. A comprehensive study by the US EPA found that emissions from compressor stations, blow down and purge, accounted for 97.7 Bscf or just over 31% of the total methane emissions attributed to the Natural Gas industry. [1] With methane (CH4) having 25 times the impact on global warming compared to carbon dioxide (CO2), and global legislation like the Regulations Respecting Reduction in the Release of Methane and Certain Volatile Organic Compounds Upstream Oil and Gas Sector (or also called Canadian Methane Rule) and regional methane reduction regulations, developing solutions to further mitigate methane emissions from process gas vents and centrifugal gas compressor seals becomes necessary as the industry moves towards near-zero targets. This paper addresses the design requirements and selection of a process gas vent recapture system and primary dry seal vent recapture system. In addition, this paper will review the design consideration during the design phase to the data collected during site operation.
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Ávila Lins de Araújo, Iuri, und Leonardo Salazar Bittencourt. „Eficácia da ventilação natural na manutenção da qualidade do ar interno em climas brasileiros“. In XIX ENCONTRO NACIONAL DE TECNOLOGIA DO AMBIENTE CONSTRUÍDO. UFRGS, 2022. http://dx.doi.org/10.46421/entac.v19i1.2092.
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A qualidade do ar interno está relacionada às taxas de renovação da ventilação, que dependem da geometria do edifício, das velocidades e direções do vento. Mas diretrizes construtivas para conforto passivo no Brasil enfocam área de abertura e rotina de ventilação, sem mencionar os ventos locais. O objetivo do presente trabalho foi avaliar a eficácia da ventilação natural em manter a qualidade do ar ao longo do ano, em climas brasileiros. O método comparou a ventilação higiênica em modelos de habitação unifamiliar, a partir de simulações com EnergyPlus. Os resultados indicam a maior eficácia de ventilação natural higiênica permanente, apesar da necessidade de ventilação mecânica suplementar.
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Daniela Lima Silva, Patrícia da Silva Oliveira, Maykon de Santana Almeida, Sthefanny Helena Rodrigues de Brito, FRANCISCO JOSÉ PATRÍCIO FRANCO und Ernane de Macedo Santos. „DESENVOLVIMENTO DE UM TUNEL DE VENTO DIDÁTICO“. In IX Congresso Nacional de Engenharia Mecânica. Rio de Janeiro, Brazil: ABCM Associação Brasileira de Engenharia e Ciências Mecânicas, 2016. http://dx.doi.org/10.20906/cps/con-2016-1211.
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Anderson, Kevin R., Christopher McNamara und Ariel Gatti. „Analysis of a Multi-Cascade Methyl Linoleate / SCO2 / Transcritical CO2 / R-410A Refrigeration Cycle for Use in High Temperature High Pressure Environments“. In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-65547.
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This paper presents the results of an analysis of a hybrid cascaded Methyl Linoleate / Supercritical (SCO2) / Transcritical CO2 / R-410A cycle for extreme environment refrigeration applications. The particular application of this cascaded CO2 refrigeration cycle stems from a space exploration application of a Venus lander mission. The payload of the Venus lander is subject an extremely harsh environment, i.e. the objective is to maintain a 1 cubic meter payload cavity at 35 °C, with dissipation of 500 W to an environmental temperature of 465 °C. Complicating the situation is the Venus local atmosphere is 9 MPa, and the atmosphere is mainly comprised of CO2 (95.5% by volume, 3.5% N2 by volume). Because this temperature is so high, to stay under the saturation dome we need some fairly exotic fluids to do a normal vapor compression system. Some of the only fluids with critical points allowing for this particular application are sulfuric acid and Fatty Acid Methyl Ester (FAME) type bio-diesels such as Methyl Linoleate (MLL). The actual heat rejection process and throttling processes are the primary challenges of this research topic. Results of a COP comparison and a lift curve are carried out in order to determine efficiency and guide feasibility of realizing the actual hardware to be used in the cycle.
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Marín Tabares, Estefanya. „ANÁLISIS PROSPECTIVO DEL MERCADO DE VEHÍCULOS ELÉCTRICOS EN COLOMBIA“. In Mujeres en ingeniería: empoderamiento, liderazgo y compromiso. Asociacion Colombiana de Facultades de Ingeniería - ACOFI, 2021. http://dx.doi.org/10.26507/ponencia.1970.
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Colombia adoptó los Objetivos de Desarrollo Sostenible para incorporarlos en sus políticas públicas. Una de las estrategias de sostenibilidad del gobierno fue estimular el uso del transporte público y, además, emitir una Ley de incentivos a los vehículos eléctricos. La Ley de incentivos a los vehículos eléctricos se emitió en el 2019 y solo tuvo en cuenta a los propietarios de automóviles. Así mismo, el gobierno nacional estableció una estrategia en un horizonte de 10 años de tener en las vías de nuestro país de 600 mil vehículos. En el presente artículo se realizó un análisis prospectivo para determinar si la venta de vehículos eléctricos en Colombia permitirá el cumplimiento de la meta definida por el gobierno. El análisis prospectivo se realizó para diferentes escenarios. Inicialmente se elaboró un análisis PEST; posteriormente, por medio del programa Mic Mac se elaboraron las matrices de impactos cruzados, y la de influencia/ dependencia, con las cuales se identificaron las variables claves del mercado. Más adelante, se efectuó el juego de actores empleando el programa Mactor. A través del juego de actores, se determinaron los actores y las variables más relevantes. Luego, se diseñaron dos escenarios haciendo uso del programa Morphol. Finalmente, para cada uno de los dos escenarios se proyectó el comportamiento de las ventas de vehículos eléctricos al año 2030.Una vez simulada las ventas de los dos escenarios, se concluye que, la meta adoptada en la Estrategia de Movilidad Eléctrica, no se cumplirá ni siquiera en el escenario optimista.
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Henrique Oliveira da Mata und João Batista Pessoa Falcão Filho. „Compensação do Efeito do Vento em Trajetórias de Veículos Suborbitais“. In IX Congresso Nacional de Engenharia Mecânica. Rio de Janeiro, Brazil: ABCM Associação Brasileira de Engenharia e Ciências Mecânicas, 2016. http://dx.doi.org/10.20906/cps/con-2016-0480.
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Danon, Carlos Alberto Ferreira, Suzane Bandeira de Magalhães und Sylvia Maria Barreto da Silva. „POR ENTRE ÁGUAS E VENTOS: NARRATIVAS CINEMATOGRÁFICAS“. In I Congresso Brasileiro On-line de Ensino, Pesquisa e Extensão. Revista Multidisciplinar de Educação e Meio Ambiente, 2022. http://dx.doi.org/10.51189/ensipex/91.
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Introdução: O projeto, Por entre águas e ventos: narrativas cinematográficas, corresponde a um trabalho de extensão acadêmica a ser desenvolvido pela Escola Bahiana de Medicina e Saúde Púbica – EBMSP (BAHIANA) sob a gestão do curso de Psicologia. Estabelecerá uma comunidade online, enlaçando através da plataforma de comunicação ZOOM, pessoas com vinculação endogâmica e exogâmica à Bahiana. Parte da fertilidade que as narrativas fílmicas, em perspectiva plural de linguagem - drama, comédia, ficção, documentário - significam o mundo através de representações compreensivas dos sentidos culturais das percepções e das interações das pessoas com as pessoas. Concebe que a experiência cinematográfica desloca para a tela uma leitura de mundo que promove novas leituras, uma onda movimento, que gera (des)continuidades que se fazem pelas águas e ventos, configurados por sentidos e significados em compartilhamentos narrativos. Assim, fomentará o encontro de pessoas e grupos, em contextos diversos, no curso da conjuntura desenhada pela pandemia, para através da discussão fílmica, trilhar pistas de fazer viver. Objetivo: Objetiva estabelecer discussões horizontais, em articulação com o universo da psicologia, para compreender a subjetividade como um marcador narrativo da história e das singularidades. Material e métodos: Configurar-seá em um cine-debate dialógico, referido nos territórios culturais de origem das pessoas, em intertextualidade, com as próprias pessoas e as linguagens cinematográficas. Resultados: Pressupõe agenda contínua, atualizada semestralmente, a ser iniciada em 2022, relacionando a comunidade da Bahiana: discentes e docentes da graduação e da pós-graduação e colaboradores dos diversos setores laborais com a comunidade estudantil da Cidade do Salvador, cursando o Ensino Médio em escolas das redes oficial ou privada. Na emergência da atividade, em razão dos efeitos provocados pela pandemia, as experiências de luto serão o elemento articulador dos encontros, com indicações de películas que fomentem essa temática. As discussões serão atualizadas em cada semestre quando a comunidade do cine-debate indicará novos temas atravessadores, em consonância, com os laços de pertencimentos construídos em cumplicidade, negociação ou conflito. Conclusão: A participação ensejará uma produção fotográfica, que retrate a comunidade extensionista no espelho da linguagem cinematográfica, a ser apresentada, sob a forma de exposição, no território da Instituição.
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S. Melo, Denise, Leonardo W. Oliveira und Janaína G. Oliveira. „Aplicação de Redes Neurais Artificiais para Previsão de Velocidade de Vento Considerando Variáveis Correlacionadas“. In Simpósio Brasileiro de Sistemas Elétricos - SBSE2020. sbabra, 2020. http://dx.doi.org/10.48011/sbse.v1i1.2293.
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Velocidade de vento consiste em uma variável aleatória cuja previsão é importante para diversas áreas, como o planejamento da operação de sistemas elétricos de potência com penetração de energia fotovoltaica. Esta variável é função de outras variáveis aleatórias, como a própria velocidade de vento em momentos anteriores, radiação global e temperatura. Redes Neurais Artificiais (RNA) vêm sendo utilizadas com frequência na construção de modelos para solucionar problemas relacionados à previsão de séries temporais em diferentes áreas. Sendo assim, o presente trabalho apresenta a implementação de uma RNA, treinada com dados extraídos de uma estação meteorológica localizada na cidade de Juiz de Fora, cujo propósito é prever velocidade de vento futura a partir de valores passados das variáveis aleatórias correlacionadas.
Berichte der Organisationen zum Thema "CO2 vents"
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Richard B. Coffin, Thomas J. Boyd, David L. Knies, Kenneth S. Grabowski, John W. Pohlman und Clark S. Mitchell. NATURAL CO2 FLOW FROM THE LOIHI VENT: IMPACT ON MICROBIAL PRODUCTION AND FATE OF THE CO2. Office of Scientific and Technical Information (OSTI), Februar 2004. http://dx.doi.org/10.2172/842638.
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Mora-Pérez, Dora Alicia, Ferney Hernando Valencia-Valencia, Francisco Javier Villadiego-Yanes, Gerardo Alberto Villa-Durán, Octavio Antonio Zuluaga-Rivera, Ovidio Gustavo Ramírez-Vanegas und Sebastián Giraldo-González. Boletín Económico Regional : Noroccidente, IV trimestre de 2022. Banco de la República Colombia, März 2023. http://dx.doi.org/10.32468/ber-norocc.tr4-2022.
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Para el cuarto trimestre de 2022, la actividad económica de la región Noroccidente señaló en general un crecimiento anual con desaceleración, de acuerdo con la información disponible. Este comportamiento es atribuido en mayor medida al debilitamiento de la demanda ante la alta inflación, alzas en las tasas de interés y elevados costos de producción. Por un lado, se moderó el incremento de las ventas y la producción industrial, además de la ocupación hotelera. Entretanto, las ventas minoritas retrocedieron al igual que la mayoría de los componentes del sector agropecuario. En cuanto a la construcción, creció el área en proceso y los despachos de concreto, pero se desaceleró el licenciamiento y cayó la venta de vivienda nueva. En el frente externo, tanto las exportaciones como las importaciones se redujeron. Por su parte, el mercado laboral tuvo una mejora ostensible en Medellín, pero se deterioró en Quibdó; mientras la inflación en la capital de Antioquia continuó registrando niveles históricamente altos.
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Hölz, Sebastian, und Mirjam Perner. Bathymetric and microbial investigations at the Grimsey Vent Field (Iceland), Cruise No. AL595, 31.5. – 20.6.2023, Kiel (Germany) – Grimsey Vent Field (Iceland) – Kiel (Germany) AUV@GVF. GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, 2023. http://dx.doi.org/10.3289/cr_al595.
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During research cruise AL595 (31.5. - 20.6.2023) onboard research vessel ALKOR, investigations were carried out at the Grimsey Hydrothermal Field offshore Northern Iceland as part of the Helmholtz InnoPool project “High CO2 – metabolic responses and bioeconomic opportunities”. For the first time, the Hover-AUVs Anton and Luise were successfully operated at water depths of up to 400m, which is close to the maximum operational depth of 500m specified for these Girona 500 AUVs. AUV Anton was used to measure high resolution multibeam data with a horizontal resolution of approximately 40cm cov- ering a total area of ca. 1.4km2. AUV Luise acquired five photo-mosaics with sub-centimeter resolution covering a total area of ca. 5.000m2. In addition, both AUVs carried CTD probes, which will allow to investigate the local distribution of hydrothermal activity. Both high-resolution bathymetry and pho- togrammetry data yield new insights into the morphology and overall structure of the vent site and its surrounding, which will be valuable for the interpretation of geophysical data previously acquired in the working area. Sampling with a multicorer (three successful deployments), a 300cm long gravity corer (five successful deployments), a BIGO lander (two successful deployments) and casts with the CTD- rosette (seven deployments) generated fluid, pore-fluid and sediment samples to be analyzed by the working groups Geomicrobiology and Biogeochemistry, Marine Natural Products and Marine Geochem- istry at GEOMAR and at Matís (Iceland, Natural Products only). Lab work to be carried out in the home labs will yield insights into the physiological adaptation of microbial communities and individual microbes to very high CO2 concentrations and will explore microbial utilization of CO2 for establishing CO2-based bioeconomic value chains. (Alkor-Berichte ; AL595)
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Mora-Pérez, Dora Alicia, María Aguilera-Díaz, Antonio Orozco-Gallo, Javier Yabrudy-Vega, Jasson Nieto-Mier, Rosemary Barcos-Robles und Yuri Reina-Aranza. Boletín Económico Regional : Costa Caribe, IV trimestre de 2022. Banco de la República Colombia, März 2023. http://dx.doi.org/10.32468/ber-costc.tr4-2022.
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Durante el cuarto trimestre de 2022, las actividades económicas de la región Caribe crecieron en términos anuales, no obstante, aminoraron su ritmo. El lado favorable estuvo impulsado por los avances en la industria, las ventas externas y el transporte, particularmente de pasajeros. En menor medida avanzó el comercio interno y la actividad constructora, que registró aumento en área construida, aunque con caída en la venta de vivienda nueva. De otro lado, se observó reducciones en el sector agropecuario en varios de sus rubros, combinado con un escenario de aumento de desembolsos de crédito para esta actividad. Entre tanto, el mercado laboral prolongó su recuperación, al aumentar los niveles de ocupación y reducirse del desempleo, a su vez que la inflación al consumidor mantuvo su tendencia alcista, ubicándose por encima del promedio nacional.
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Dawson, Greer, Gai Moore, Anton du Toit, Rebecca Gordon, Susie Thompson, Haitham Taha und Shallu Sharma. Update: What is known about aerosol transmission of SARS-CoV-2? The Sax Institute, Oktober 2020. http://dx.doi.org/10.57022/onai3530.
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This Evidence Snapshot is an updated rapid review of current knowledge about aerosol transmission of COVID-19. The original review was completed in August 2020 and this updated review in October 2020. The updated review found that the weight of evidence was that aerosol transmission of SARS-CoV-2 does occur. Five reviews found that the virus may spread as an aerosol. Experimental studies demonstrated aerosolisation of the virus with persistence from 90 minutes to 16 hours, and evidence for horizontal transmission was found for ranges from two to eight metres. Environmental sampling studies typically found viral RNA both in the air and on air vents. Eight out of ten investigations of outbreaks reviewed found that transmission occurred without close direct contact. Risk of transmission was thought to be associated with shared indoor space, closed air recirculation and singing. Eighteen articles were reviewed in the updated report in addition to the nineteen articles in the original report, for a total of thirty-seven articles.
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Mora-Pérez, Dora Alicia, Julio Escobar-Potes, Arley Barandica-Villegas, Diana M. Cortázar-Gómez, Johana Andrea Sanabria-Domínguez und Cristian Camilo Guevara-Acevedo. Boletín Económico Regional: Suroccidente, IV trimestre de 2022. Banco de la República Colombia, März 2023. http://dx.doi.org/10.32468/ber-surocc.tr4-2022.
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En el cuarto trimestre de 2022, la actividad económica de Suroccidente registró un crecimiento anual; aunque, con menor dinámica respecto a los trimestres previos. Los mejores resultados se observaron en la industria manufacturera y los desembolsos de crédito agropecuario de Finagro para estimular este sector, cuya oferta estuvo afectada nuevamente por la intensidad de las precipitaciones y el alto costo de los insumos. Por el contrario, se evidenciaron reducciones en las ventas reales del comercio interno, incluidas las de vehículos nuevos, el transporte, la construcción de edificaciones y la venta de vivienda nueva; en esta última debido al agotamiento de los subsidios a compradores, y a los mayores costos de financiación, tanto en UVR por la alta inflación, como en tasas por la política monetaria. Finalmente, la tasa de desempleo cerró a la baja en las tres ciudades capitales de la región; mientras que, la inflación fue alta al triplicarse los precios de la canasta de alimentos, seguidos del costo de los servicios públicos y de los combustibles.
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Henríquez, Francisca. Microcrédito y su impacto: Un acercamiento con datos chilenos. Inter-American Development Bank, Januar 2009. http://dx.doi.org/10.18235/0012100.
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Esta investigación busca contribuir empíricamente a la discusión sobre el efecto de las microfinanzas. El estudio presenta una evaluación de impacto del uso intensivo del crédito sobre el desempeño de microempresas chilenas con acceso a este tipo de financiamiento. Los resultados encontrados, utilizando técnicas de matching, muestran efectos deseables sobre la evolución del desempeño de las empresas producto del uso intensivo del crédito, versus la elección de fuentes alternativas de financiamiento. Los impactos encontrados pueden ser asociados a incrementos en bienestar, derivados del mayor empleo demandado y los aumentos en formalidad de las microempresas. Además, el crecimiento en las ventas encontrado puede generar incrementos en ingresos familiares en el corto o largo plazo. A través de la evidencia se constatan los beneficios del acceso y utilización del crédito como estrategia de financiamiento.
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Mora, Dora Alicia, María Aguilera Díaz, Antonio Orozco Gallo, Javier Yabrudy Vega, Jasson Nieto Mier, Rosemary Barcos Robles und Yuri Reina Aranza. Boletín Económico Regional : Costa Caribe, I trimestre de 2023. Banco de la República, Juni 2023. http://dx.doi.org/10.32468/ber-costc.tr1-2023.
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Durante el primer trimestre de 2022, la economía de la región Caribe mostró un aumento anual, dado el buen desempeño en las principales actividades económicas, explicado por: la industria, en donde se vio avance en la producción, las ventas y el empleo; la construcción que registró incrementos en el área en proceso, el área causada, el metraje aprobado para construir y en las ventas de vivienda nueva; el agropecuario con un buen volumen de productos agrícolas, aunque un descenso en el ganado vacuno para sacrificio; el transporte por la mayor movilización de pasajeros, tanto urbano como aéreo; y el comercio exterior que mantuvo el crecimiento tanto en exportaciones como importaciones. Lo anterior se vio reflejado en los indicadores del mercado laboral con el aumento de la tasa de ocupación y descenso del desempleo. Por el contrario, la inflación continuó con su tendencia alcista iniciada un año atrás.
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Mora, Dora Alicia, Ferney H. Valencia Valencia, Estefany Hernández García, Francisco J. Villadiego Yanes, Ovidio G. Ramírez Vanegas und Sebastián Giraldo González. Boletín Económico Regional : Noroccidente, I trimestre de 2023. Banco de la República, Juni 2023. http://dx.doi.org/10.32468/ber-norocc.tr1-2023.
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En el primer trimestre de 2023 la economía de la región Noroccidente profundizó su desaceleración. El contexto de alta inflación, mayores tasas de interés e incertidumbre condicionaron los resultados de las actividades productivas de la región vía una menor demanda. Con base en lo anterior, la producción industrial, las ventas minoristas y la mayoría de los indicadores del sector de la construcción y del agropecuario se contrajeron. Asimismo, se estancó en general el transporte y mermó la ocupación hotelera. Por su parte, la producción minera creció y coincidió con el incremento de las exportaciones de oro e impulsó el total de las ventas externas; no obstante, cayeron las importaciones mientras que aumentó la recepción de remesas en Antioquia. Entretanto, el desempleo en Medellín y el Valle de Aburrá bajó, mientras en Quibdó creció y fue el más alto del país. Por último, la inflación se mantuvo en niveles altos, pero con una ligera moderación en marzo.
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Templado, Ivana, und Daniel Artana. Análisis del impacto de la factura electrónica en Argentina. Inter-American Development Bank, Januar 2018. http://dx.doi.org/10.18235/0007189.
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Este trabajo tiene el objetivo de evaluar el impacto que tuvo la introducción de la FE en las ventas declaradas en la Argentina. La información para el análisis fue provista por la Administración Federal de Ingresos Públicos (AFIP) quien armó una base a nivel de contribuyente, desde el año 2005 hasta 2016, para todos los contribuyentes con ventas anuales mayores a $500.000 y menores a $600 millones. La base se delimitó entre estas cotas mínima y máxima para concentrar el estudio en la masa crítica que tiene mayor riqueza en el análisis y por la necesidad de preservar el secreto fiscal. Los resultados muestran que la introducción de la FE parece haber generado un aumento promedio en la recaudación de entre 0% en 2008 y 2009 hasta 10% en 2013, con un impacto positivo en 6 de los 9 años analizados.