The Zinc-Finger Thylakoid-Membrane Protein FIP Is Involved With Abiotic Stress Response in Arabidopsis thaliana

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Karina L. Lopes

2018-04-01

Full Text Available Many plant genes have their expression modulated by stress conditions. Here, we used Arabidopsis FtsH5 protease, which expression is regulated by light stress, as bait in a yeast two-hybrid screen to search for new proteins involved in the stress response. As a result, we found FIP (FtsH5 Interacting Protein, which possesses an amino proximal cleavable transit peptide, a hydrophobic membrane-anchoring region, and a carboxyl proximal C4-type zinc-finger domain. In vivo experiments using FIP fused to green fluorescent protein (GFP showed a plastid localization. This finding was corroborated by chloroplast import assays that showed FIP inserted in the thylakoid membrane. FIP expression was down-regulated in plants exposed to high light intensity, oxidative, salt, and osmotic stresses, whereas mutant plants expressing low levels of FIP were more tolerant to these abiotic stresses. Our data shows a new thylakoid-membrane protein involved with abiotic stress response in Arabidopsis thaliana.

Nonlinear Dielectric Spectroscopy as an Indirect Probe of Metabolic Activity in Thylakoid Membrane

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John H. Miller

2011-01-01

Full Text Available Nonlinear dielectric spectroscopy (NDS is a non-invasive probe of cellular metabolic activity with potential application in the development of whole-cell biosensors. However, the mechanism of NDS interaction with metabolic membrane proteins is poorly understood, partly due to the inherent complexity of single cell organisms. Here we use the light-activated electron transport chain of spinach thylakoid membrane as a model system to study how NDS interacts with metabolic activity. We find protein modification, as opposed to membrane pump activity, to be the dominant source of NDS signal change in this system. Potential mechanisms for such protein modifications include reactive oxygen species generation and light-activated phosphorylation.

The mechanism of anthracene interaction with photosynthetic apparatus: A study using intact cells, thylakoid membranes and PS II complexes isolated from Chlamydomonas reinhardtii

International Nuclear Information System (INIS)

Aksmann, Anna; Shutova, Tatiana; Samuelsson, Goeran; Tukaj, Zbigniew

2011-01-01

Intact cells of Chlamydomonas reinhardtii as well as isolated thylakoid membranes and photosystem II complexes were used to examine a possible mechanism of anthracene (ANT) interaction with the photosynthetic apparatus. Since ANT concentrations above 1 mM were required to significantly inhibit the rate of oxygen evolution in PS II membrane fragments it may indicate that the toxicant did not directly interact with this photosystem. On the other hand, stimulation of oxygen uptake by ANT-treated thylakoids suggested that ANT could either act as an artificial electron acceptor in the photosynthetic electron transport chain or function as an uncoupler. Electron transfer from excited chlorophyll to ANT is impossible due to the very low reduction potential of ANT and therefore we propose that toxic concentrations of ANT increase the thylakoid membrane permeability and thereby function as an uncoupler, enhancing electron transport in vitro. Hence, its unspecific interference with photosynthetic membranes in vitro suggests that the inhibitory effect observed on intact cell photosynthesis is caused by uncoupling of phosphorylation.

Enhanced thermal stability of the thylakoid membranes from spruce. A comparison with selected angiosperms

Czech Academy of Sciences Publication Activity Database

Karlický, Václav; Kurasová, Irena; Ptáčková, B.; Večeřová, Kristýna; Urban, Otmar; Špunda, Vladimír

2016-01-01

Roč. 130, 1-3 (2016), s. 357-371 ISSN 0166-8595 R&D Projects: GA MŠk(CZ) LO1415; GA ČR GA13-28093S Institutional support: RVO:67179843 Keywords : Norway spruce * Thermal stability * Circular dichroism * Photosystem II organization * Thylakoid membrane Subject RIV: ED - Physiology Impact factor: 3.864, year: 2016

Changes in some thylakoid membrane proteins and pigments upon desiccation of the resurrection plant Haberlea rhodopensis.

Science.gov (United States)

Georgieva, Katya; Röding, Anja; Büchel, Claudia

2009-09-15

The changes in some proteins involved in the light reactions of photosynthesis of the resurrection plant Haberlea rhodopensis were examined in connection with desiccation. Fully hydrated (control) and completely desiccated plants (relative water content (RWC) 6.5%) were used for thylakoid preparations. The chlorophyll (Chl) a to Chl b ratios of thylakoids isolated from control and desiccated leaves were very similar, which was also confirmed by measuring their absorption spectra. HPLC analysis revealed that beta-carotene content was only slightly enhanced in desiccated leaves compared with the control, but the zeaxanthin level was strongly increased. Desiccation of H. rhodopensis to an air-dried state at very low light irradiance led to a little decrease in the level of D1, D2, PsbS and PsaA/B proteins in thylakoids, but a relative increase in LHC polypeptides. To further elucidate whether the composition of the protein complexes of the thylakoid membranes had changed, we performed a separation of solubilized thylakoids on sucrose density gradients. In contrast to spinach, Haberlea thylakoids appeared to be much more resistant to the same solubilization procedure, i.e. complexes were not separated completely and complexes of higher density were found. However, the fractions analyzed provided clear evidence for a move of part of the antenna complexes from PSII to PSI when plants became desiccated. This move was also confirmed by low temperature emission spectra of thylakoids. Overall, the photosynthetic proteins remained comparatively stable in dried Haberlea leaves when plants were desiccated under conditions similar to their natural habitat. Low light during desiccation was enough to induce a rise in the xanthophyll zeaxanthin and beta-carotene. Together with the extensive leaf shrinkage and some leaf folding, increased zeaxanthin content and the observed shift in antenna proteins from PSII to PSI during desiccation of Haberlea contributed to the integrity of the

Mediator-assisted photocurrent extraction from the thylakoids

International Nuclear Information System (INIS)

Yu, Yue; Zuo, Fulin; Li, Chen-Zhong

2014-01-01

Photocurrent extracted from the thylakoids has been studied as a function of electron mediator concentration. Phenazine methosulfate is used to facilitate the charge transfer from the thylakoid's charge transport chain to the outside medium. The photocurrent has been shown to originate from the photosynthesis on the thylakoid membranes. Comparing with a previous study using para-Benzoquinone as the mediator, a similar peak effect in the photocurrent as a function of concentration is observed, but the magnitude of the current is nearly a thousand times greater. A semi-quantitative analysis is presented to explain the data found in those systems

Overaccumulation of glycine betaine makes the function of the thylakoid membrane better in wheat under salt stress

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Fengxia Tian

2017-02-01

Full Text Available Wheat (Triticum aestivum L. lines T1, T4, and T6 were genetically modified to increase glycine betaine (GB synthesis by introduction of the BADH (betaine aldehyde dehydrogenase, BADH gene from mountain spinach (Atriplex hortensis L.. These transgenic lines and WT of wheat (T. aestivum L. were used to study the effect of increased GB synthesis on wheat tolerance to salt stress. Salt stress due to 200 mmol L−1 NaCl impaired the photosynthesis of the four wheat lines, as indicated by declines in net photosynthetic rate (Pn, stomatal conductance (Gs, maximum photochemical efficiency of PSII (Fv/Fm, and actual photochemical efficiency of PSII (ФPSII and an increase in intercellular CO2 concentration (Ci. In comparison with WT, the effect of salinity on the three transgenic lines was mild. Salt stress caused disadvantageous changes in lipids and their fatty acid compositions in the thylakoid membrane of the transgenic lines and WT. Under salt stress, the three transgenic lines showed slightly higher chlorophyll and carotenoid contents and higher Hill reaction activities and Ca2+-ATPase activity than WT. All the results suggest that overaccumulation of GB resulting from introduction of the BADH gene can enhance the salt tolerance of transgenic plants, especially in the protection of the components and function of thylakoid membranes, thereby making photosynthesis better. Changes in lipids and fatty acid compositions in the thylakoid membrane may be involved in the increased salt stress tolerance of the transgenic lines.

The chloroplast thylakoid membrane system is a molecular conveyor belt.

Science.gov (United States)

Critchley, C

1988-10-01

Light drives photosynthesis, but paradoxically light is also the most variable environmental factor influencing photosynthesis both qualitatively and quantitatively. The photosynthetic apparatus of higher plants is adaptable in the extreme, as exemplified by its capacity for acclimation to very bright sunny or deeply shaded conditions. It can also respond to rapid changes in light such as sunflecks. In this paper I offer a model that i) explains the thylakoid membrane organisation into grana stacks and stroma lamellae, ii) proposes a role for rapid D1 protein turnover and LHCII phosphorylation, and iii) suggests a mechanism for photoinhibition. I argue that the photosynthetic membrane system is dynamic in three dimensions, so much so that, in the light, it is in constant motion and operates in a manner somewhat analogous to a conveyor belt. D1 protein degradation is proposed to be the motor that drives this system. Photoinhibition is suggested to be due to the arrest of D1 protein turnover.

Influence of thylakoid membrane lipids on the structure of aggregated light-harvesting complexes of the diatom Thalassiosira pseudonana and the green alga Mantoniella squamata.

Science.gov (United States)

Schaller-Laudel, Susann; Latowski, Dariusz; Jemioła-Rzemińska, Małgorzata; Strzałka, Kazimierz; Daum, Sebastian; Bacia, Kirsten; Wilhelm, Christian; Goss, Reimund

2017-07-01

The study investigated the effect of the thylakoid membrane lipids monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulphoquinovosyldiacylglycerol (SQDG) and phosphatidylglycerol (PG) on the structure of two algal light-harvesting complexes (LHCs). In contrast to higher plants whose thylakoid membranes are characterized by an enrichment of the neutral galactolipids MGDG and DGDG, both the green alga Mantoniella squamata and the centric diatom Thalassiosira pseudonana contain membranes with a high content of the negatively charged lipids SQDG and PG. The algal thylakoids do not show the typical grana-stroma differentiation of higher plants but a regular arrangement. To analyze the effect of the membrane lipids, the fucoxanthin chlorophyll protein (FCP) complex of T. pseudonana and the LHC of M. squamata (MLHC) were prepared by successive cation precipitation using Triton X-100 as detergent. With this method, it is possible to isolate LHCs with a reduced amount of associated lipids in an aggregated state. The results from 77 K fluorescence and photon correlation spectroscopy show that neither the neutral galactolipids nor the negatively charged lipids are able to significantly alter the aggregation state of the FCP or the MLHC. This is in contrast to higher plants where SQDG and PG lead to a strong disaggregation of the LHCII whereas MGDG and DGDG induce the formation of large macroaggregates. The results indicate that LHCs which are integrated into thylakoid membranes with a high amount of negatively charged lipids and a regular arrangement are less sensitive to lipid-induced structural alterations than their counterparts in membranes enriched in neutral lipids with a grana-stroma differentiation. © 2017 Scandinavian Plant Physiology Society.

Carbonic anhydrase activity of integral-functional complexes of thylakoid membranes of spinach chloroplasts

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A. V. Semenihin

2015-06-01

Full Text Available Isolated thylakoid membranes were disrupted by treatment with nonionic detergents digitonin or dodecyl maltoside. Solubilized polypeptide complexes were separated by native gel charge shift electrophoresis. The position of ATP-synthase complex and its isolated catalytic part (CF1 within gel was determined using the color reaction for ATPase activity. Due to the presence of cytochromes, the red band in unstained gels corresponded to the cytochrome b6f complex. Localization of the cytochrome b6f complex, ATP synthase and coupling CF1 in the native gel was confirmed by their subunit composition determined after SDS-electrophoretic analysis. Carbonic anhydrase (CA activity in polypeptide zones of PS II, cytochrome b6f complex, and ATP-synthase CF1 was identified in native gels using indicator bromothymol blue. CA activity of isolated CF1 in solution was determined by infrared gas analysis as the rate of bicarbonate dehydration. The water-soluble acetazolamide, an inhibitor of CA, unlike lipophilic ethoxyzolamide inhibited CA activity of CF1. Thus, it was shown for the first time that ATP-synthase has a component which is capable of catalyzing the interconversion of forms of carbonic acid associated with proton exchange. The data obtained suggest the presence of multiple forms of carbonic anhydrase in the thylakoid membranes of spinach chloroplasts and confirm their involvement in the proton transfer to the ATP synthase.

Two roles of thylakoid lipids in modifying the activity of herbicides which inhibit photosystem II

International Nuclear Information System (INIS)

Kupatt, C.C. Jr.

1985-01-01

Thylakoid lipids may modify the activity of herbicides which inhibit electron transport at the Q/sub B/ protein of photosystem II in two ways: (1) lipids can act as a hydrophobic barrier to a binding site localized close to the loculus of the membrane, and (2) changes in lipid composition can reduce the ability of inhibitors to block electron transport, possibly due to a change in the conformation of the Q/sub B/ protein. The herbicide binding site was localized close to the locular side of the thylakoid membrane by determining the activity of a number of substituted phenylurea and s-triazine herbicides in inverted and non-inverted thylakoids. Quantitative structure-activity relationship analysis showed that inversion of thylakoids reduced the requirement of molecular lipophilicity deemed necessary for phenylurea activity in non-inverted membranes, whereas s-triazines exhibited no differences in the lipophilicity requirement in thylakoid membranes of either orientation. The binding affinity of 14 C-diuron was reduced in bicarbonate-depleted thylakoids relative to reconstituted or control membranes, as is the case with atrazine binding. These observations support a model of the herbicide binding site containing both common and herbicide family specific binding domains. Thylakoids isolated either from detached lambs quarters (Chenopodium album L.) leaves, treated with SAN 6706, or from soybean (Glycine max L.), with norflurazon or pyrazon applied preemergence, exhibited decreased susceptibility to atrazine. The ability of lipid-modifying treatments to decrease the atrazine susceptibility of field-grown soybeans was also investigated

Is There Excitation Energy Transfer between Different Layers of Stacked Photosystem-II-Containing Thylakoid Membranes?

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Farooq, Shazia; Chmeliov, Jevgenij; Trinkunas, Gediminas; Valkunas, Leonas; van Amerongen, Herbert

2016-04-07

We have compared picosecond fluorescence decay kinetics for stacked and unstacked photosystem II membranes in order to evaluate the efficiency of excitation energy transfer between the neighboring layers. The measured kinetics were analyzed in terms of a recently developed fluctuating antenna model that provides information about the dimensionality of the studied system. Independently of the stacking state, all preparations exhibited virtually the same value of the apparent dimensionality, d = 1.6. Thus, we conclude that membrane stacking does not affect the efficiency of the delivery of excitation energy toward the reaction centers but ensures a more compact organization of the thylakoid membranes within the chloroplast and separation of photosystems I and II.

The evolutionarily conserved protein PHOTOSYNTHESIS AFFECTED MUTANT71 is required for efficient manganese uptake at the thylakoid membrane in Arabidopsis

DEFF Research Database (Denmark)

Schneider, Anja; Steinberger, Iris; Herdean, Andrei

2016-01-01

In plants, algae, and cyanobacteria, photosystem II (PSII) catalyzes the light-driven oxidation of water. The oxygen-evolving complex of PSII is a Mn4CaO5 cluster embedded in a well-defined protein environment in the thylakoid membrane. However, transport of manganese and calcium into the thylako...... was restored by supplementation with Mn2+, but not Ca2+. Furthermore, PAM71 suppressed the Mn2+-sensitive phenotype of the yeast mutant Δpmr1. Therefore, PAM71 presumably functions in Mn2+ uptake into thylakoids to ensure optimal PSII performance....

Molecular analysis of a thylakoid K+channel

International Nuclear Information System (INIS)

1999-01-01

The work undertaken sought to use a novel probe to identify and clone plant ion (K) channels. It was also proposed that in vitro biochemical studies of cation transport across purified preparations of thylakoid membrane be employed to characterize a putative K channel in this membrane system. Over the last several years, an enormous data base of partially-sequenced mRNAs and numerous genomes (including those of plants) has evolved and provides a powerful alternative to this brute-force approach to identify and clone cDNAs encoding physiologically important membrane proteins such as channels. The utility of searching genetic databases for relevant sequences, in addition to the difficulty of working with membrane proteins, led to changes in research focus during the granting period. During the course of the funding period, work was finished up which documented the presence of a K channel in the thylakoid membrane and demonstrated that K fluxes through this channel were required for optimal photosynthetic activity, likely due to the requirement for charge balancing of proton flux

Molecular analysis of a thylakoid K+channel

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-09-10

The work undertaken sought to use a novel probe to identify and clone plant ion (K) channels. It was also proposed that in vitro biochemical studies of cation transport across purified preparations of thylakoid membrane be employed to characterize a putative K channel in this membrane system. Over the last several years, an enormous data base of partially-sequenced mRNAs and numerous genomes (including those of plants) has evolved and provides a powerful alternative to this brute-force approach to identify and clone cDNAs encoding physiologically important membrane proteins such as channels. The utility of searching genetic databases for relevant sequences, in addition to the difficulty of working with membrane proteins, led to changes in research focus during the granting period. During the course of the funding period, work was finished up which documented the presence of a K channel in the thylakoid membrane and demonstrated that K fluxes through this channel were required for optimal photosynthetic activity, likely due to the requirement for charge balancing of proton flux.

Ribosomal protein S6 kinase1 coordinates with TOR-Raptor2 to regulate thylakoid membrane biosynthesis in rice.

Science.gov (United States)

Sun, Linxiao; Yu, Yonghua; Hu, Weiqin; Min, Qiming; Kang, Huiling; Li, Yilu; Hong, Yue; Wang, Xuemin; Hong, Yueyun

2016-07-01

Ribosomal protein S6 kinase (S6K) functions as a key component in the target of rapamycin (TOR) pathway involved in multiple processes in eukaryotes. The role and regulation of TOR-S6K in lipid metabolism remained unknown in plants. Here we provide genetic and pharmacological evidence that TOR-Raptor2-S6K1 is important for thylakoid galactolipid biosynthesis and thylakoid grana modeling in rice (Oryza sativa L.). Genetic suppression of S6K1 caused pale yellow-green leaves, defective thylakoid grana architecture. S6K1 directly interacts with Raptor2, a core component in TOR signaling, and S6K1 activity is regulated by Raptor2 and TOR. Plants with suppressed Raptor2 expression or reduced TOR activity by inhibitors mimicked the S6K1-deficient phenotype. A significant reduction in galactolipid content was found in the s6k1, raptor2 mutant or TOR-inhibited plants, which was accompanied by decreased transcript levels of the set of genes such as lipid phosphate phosphatase α5 (LPPα5), MGDG synthase 1 (MGD1), and DGDG synthase 1 (DGD1) involved in galactolipid synthesis, compared to the control plants. Moreover, loss of LPPα5 exhibited a similar phenotype with pale yellow-green leaves. These results suggest that TOR-Raptor2-S6K1 is important for modulating thylakoid membrane lipid biosynthesis, homeostasis, thus enhancing thylakoid grana architecture and normal photosynthesis ability in rice. Copyright © 2016 Elsevier B.V. All rights reserved.

Operation of trans-thylakoid thiol-metabolizing pathways in photosynthesis

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Mohamed eKaramoko

2013-11-01

Full Text Available Thiol oxidation to disulfides and the reverse reaction, i.e. disulfide reduction to free thiols, are under the control of catalysts in vivo. Enzymatically assisted thiol-disulfide chemistry is required for the biogenesis of all energy-transducing membrane systems. However, until recently, this had only been demonstrated for the bacterial plasma membrane. Long considered to be vacant, the thylakoid lumen has now moved to the forefront of photosynthesis research with the realization that its proteome is far more complicated than initially anticipated. Several lumenal proteins are known to be disulfide bonded in Arabidopsis, highlighting the importance of sulfhydryl oxidation in the thylakoid lumen. While disulfide reduction in the plastid stroma is known to activate several enzymatic activities, it appears that it is the reverse reaction, i.e. thiol oxidation that is required for the activity of several lumen-resident proteins. This paradigm for redox regulation in the thylakoid lumen has opened a new frontier for research in the field of photosynthesis. Of particular significance in this context is the discovery of trans-thylakoid redox pathways controlling disulfide bond formation and reduction, which are required for photosynthesis.

Kinetic and spectroscopic studies of cytochrome b-563 in isolated cytochrome b/f complex and in thylakoid membranes

Energy Technology Data Exchange (ETDEWEB)

Hind, G.; Clark, R.D.; Houchins, J.P.

1983-01-01

Extensive studies, performed principally by Hauska, Hurt and collaborators, have shown that a cytochrome (cyt) b/f complex isolated from photosynthetic membranes of spinach or Anabaena catalyzes electron transport from plastoquinol (PQH/sub 2/) to plastocyanin or algal cyt c-552. The complex from spinach thylakoids generated a membrane potential when reconstituted into liposomes, and although the electrogenic mechanism remains unknown, a key role for cyt b-563 is widely accepted. Electrogenesis by a Q-cycle mechanism requires a plastoquinone (PQ) reductase to be associated with the stromal side of the thylakoid b/f complex though this activity has yet to be demonstrated. It seemed possible that more gentle isolation of the complex might yield a form containing additional polypeptides, perhaps including a PQ reductase or a component involved in returning electrons from reduced ferredoxin to the complex in cyclic electron flow. Optimization of the isolation of cyt b/f complex for Hybrid 424 spinach from a growth room was also required. The procedure we devised is compared to the protocol of Hurt and Hauska (1982). 13 references.

Small-angle neutron scattering study of the ultrastructure of chloroplast thylakoid membranes - Periodicity and structural flexibility of the stroma lamellae

DEFF Research Database (Denmark)

Posselt, Dorthe; Nagy, Gergely; Kirkensgaard, Jacob J. K.

2012-01-01

The multilamellar organization of freshly isolated spinach and pea chloroplast thylakoid membranes was studied using small-angle neutron scattering. A broad peak at similar to 0.02 angstrom(-1) is ascribed to diffraction from domains of ordered, unappressed stroma lamellae, revealing a repeat dis...

Characteristics and functionality of appetite-reducing thylakoid powders produced by three different drying processes.

Science.gov (United States)

Östbring, Karolina; Sjöholm, Ingegerd; Sörenson, Henrietta; Ekholm, Andrej; Erlanson-Albertsson, Charlotte; Rayner, Marilyn

2018-03-01

Thylakoids, a chloroplast membrane extracted from green leaves, are a promising functional ingredient with appetite-reducing properties via their lipase-inhibiting effect. Thylakoids in powder form have been evaluated in animal and human models, but no comprehensive study has been conducted on powder characteristics. The aim was to investigate the effects of different isolation methods and drying techniques (drum-drying, spray-drying, freeze-drying) on thylakoids' physicochemical and functional properties. Freeze-drying yielded thylakoid powders with the highest lipase-inhibiting capacity. We hypothesize that the specific macromolecular structures involved in lipase inhibition were degraded to different degrees by exposure to heat during spray-drying and drum-drying. We identified lightness (Hunter's L-value), greenness (Hunter's a-value), chlorophyll content and emulsifying capacity to be correlated to lipase-inhibiting capacity. Thus, to optimize the thylakoids functional properties, the internal membrane structure indicated by retained green colour should be preserved. This opens possibilities to use chlorophyll content as a marker for thylakoid functionality in screening processes during process optimization. Thylakoids are heat sensitive, and a mild drying technique should be used in industrial production. Strong links between physicochemical parameters and lipase inhibition capacity were found that can be used to predict functionality. The approach from this study can be applied towards production of standardized high-quality functional food ingredients. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

The transporter SynPAM71 is located in the plasma membrane and thylakoids, and mediates manganese tolerance in Synechocystis PCC6803

DEFF Research Database (Denmark)

Gandini, Chiara; Schmidt, Sidsel Birkelund; Husted, Søren

2017-01-01

symptoms were observed in WT cells exposed to excess Mn. Moreover, CyanoP, which is involved in the early steps of PSII assembly, is massively upregulated in ΔSynPAM71. SynPAM71 was detected in both the plasma membrane and, to a lesser extent, the thylakoid membranes. Our results suggest that SynPAM71......Manganese (Mn) is an essential constituent of photosystem II (PSII) and therefore indispensable for oxygenic photosynthesis. Very little is known about how Mn is transported, delivered and retained in photosynthetic cells. Recently, the thylakoid-localized transporter PAM71 has been linked...... to chloroplast Mn homeostasis in Arabidopsis thaliana. Here, we characterize the function of its homolog in Synechocystis (SynPAM71). We used a loss-of-function line (ΔSynPAM71), wild-type (WT) cells exposed to Mn stress and strains expressing a tagged variant of SynPAM71 to characterize the role of SynPAM71...

Purification and characterization of a thylakoid protein kinase

International Nuclear Information System (INIS)

Coughlan, S.J.; Hind, G.

1986-01-01

Control of state transitions in the thylakoid by reversible phosphorylation of the light-harvesting chlorophyll a/b protein complex of photosystem II (LHC-II) is modulated by a kinase. The kinase catalyzing this phosphorylation is associated with the thylakoid membrane, and is regulated by the redox state of the plastoquinone pool. The isolation and partial purification from spinach thylakoids of two protein kinases (CPK1, CPK2) of apparent molecular masses 25 kDa and 38 kDa has been reported. Neither enzyme utilizes isolated LHC-II as a substrate. The partial purification of a third protein kinase (LHCK) which can utilize both lysine-rich histones (IIIs and Vs) and isolated LHC-II as substrate has now been purified to homogeneity and characterized by SDS-polyacrylamide gel electrophoresis as a 64 kDa peptide. From a comparison of the two isolation procedures we have concluded that CPK1 is indeed a protein kinase, but has a lower specific activity than that of LHCK. 8 refs., 4 figs

Thylakoids promote release of the satiety hormone cholecystokinin while reducing insulin in healthy humans

DEFF Research Database (Denmark)

Köhnke, Rickard; Lindbo, Agnes; Larsson, Therese

2009-01-01

(CCK, leptin and ghrelin), insulin and blood metabolites (glucose and free fatty acids). RESULTS: The CCK level increased, in particular between the 120 min time-point and onwards, the ghrelin level was reduced at 120 min and leptin level increased at 360 min after intake of the thylakoid-enriched meal....... The insulin level was reduced, whereas glucose concentrations were unchanged. Free fatty acids were reduced between time-point 120 min and onwards after the thylakoid meal. CONCLUSIONS: The addition of thylakoids to energy-dense food promotes satiety signals and reduces insulin response during a single meal......OBJECTIVE: The effects of a promising new appetite suppressor named "thylakoids" (membrane proteins derived from spinach leaves) were examined in a single meal in man. Thylakoids inhibit the lipase/colipase hydrolysis of triacylglycerols in vitro and suppress food intake, decrease body-weight gain...

Thylakoids suppress appetite by increasing cholecystokinin resulting in lower food intake and body weight in high-fat fed mice

DEFF Research Database (Denmark)

Köhnke, Rickard; Lindqvist, Andreas; Göransson, Nathanael

2009-01-01

Thylakoids are membranes isolated from plant chloroplasts which have previously been shown to inhibit pancreatic lipase/colipase catalysed hydrolysis of fat in vitro and induce short-term satiety in vivo. The purpose of the present study was to examine if dietary supplementation of thylakoids cou...

Red Bell Pepper Chromoplasts Exhibit in Vitro Import Competency and Membrane Targeting of Passenger Proteins from the Thylakoidal Sec and ΔpH Pathways but Not the Chloroplast Signal Recognition Particle Pathway1

Science.gov (United States)

Summer, Elizabeth J.; Cline, Kenneth

1999-01-01

Chloroplast to chromoplast development involves new synthesis and plastid localization of nuclear-encoded proteins, as well as changes in the organization of internal plastid membrane compartments. We have demonstrated that isolated red bell pepper (Capsicum annuum) chromoplasts contain the 75-kD component of the chloroplast outer envelope translocon (Toc75) and are capable of importing chloroplast precursors in an ATP-dependent fashion, indicating a functional general import apparatus. The isolated chromoplasts were able to further localize the 33- and 17-kD subunits of the photosystem II O2-evolution complex (OE33 and OE17, respectively), lumen-targeted precursors that utilize the thylakoidal Sec and ΔpH pathways, respectively, to the lumen of an internal membrane compartment. Chromoplasts contained the thylakoid Sec component protein, cpSecA, at levels comparable to chloroplasts. Routing of OE17 to the lumen was abolished by ionophores, suggesting that routing is dependent on a transmembrane ΔpH. The chloroplast signal recognition particle pathway precursor major photosystem II light-harvesting chlorophyll a/b protein failed to associate with chromoplast membranes and instead accumulated in the stroma following import. The Pftf (plastid fusion/translocation factor), a chromoplast protein, integrated into the internal membranes of chromoplasts during in vitro assays, and immunoblot analysis indicated that endogenous plastid fusion/translocation factor was also an integral membrane protein of chromoplasts. These data demonstrate that the internal membranes of chromoplasts are functional with respect to protein translocation on the thylakoid Sec and ΔpH pathways. PMID:9952453

Resonance Raman spectroscopy of xanthophylls in pigment mutant thylakoid membranes of pea.

Science.gov (United States)

Andreeva, Atanaska; Stoitchkova, Katerina; Busheva, Mira; Apostolova, Emilia; Várkonyi, Zsuzsanna; Garab, Gyözö

Low-temperature resonance Raman spectroscopy was used to study the changes in the molecular structure and configuration of the major xanthophylls in thylakoid membranes isolated from mutants of pea with modified pigment content and altered structural organization of their pigment-protein complexes. The Raman spectra contained four known groups of bands, nu(1)-nu(4), which could be assigned to originate mainly from the long wavelength absorbing lutein and neoxanthin upon 514.5 nm and at 488 nm excitations, respectively. The overall configuration of these bound xanthophyll molecules in the mutants appeared to be similar to the wild type, and the configuration in the wild type was almost identical with that in the isolated main chlorophyll a/b light harvesting protein complex of photosystem II (LHCII). Significant differences were found mainly in the region of nu(4) (around 960 cm(-1)), which suggest that the macroorganization of PS II-LHCII supercomplexes and/or of the LHCII-only domains are modified in the mutants compared to the wild type. Copyright 2004 Wiley Periodicals, Inc. Biopolymers, 2004

Analysis of ionic channels by a flash spectrophotometric technique applicable to thylakoid membranes : CF0, the proton channel of the chloroplast ATP synthase, and, for comparison, gramicidin

NARCIS (Netherlands)

Lill, H.; Althoff, Gerd; Junge, Wolfgang

We previously introduced a flash spectrophotometric method to analyze proton conduction by CF0 in vesicles derived from thylakoid membranes (H. Lill, S. Engelbrecht, G. Schönknecht & W. Junge, 1986, Eur. J. Biochem.160:627-634). The unit conductance of CF0, as revealed by this technique, was orders

Tat proteins as novel thylakoid membrane anchors organize a biosynthetic pathway in chloroplasts and increase product yield 5-fold

DEFF Research Database (Denmark)

Henriques de Jesus, Maria Perestrello Ramos; Nielsen, Agnieszka Janina Zygadlo; Mellor, Silas Busck

2017-01-01

to their complex structures. Some of the crucial enzymes catalyzing their biosynthesis are the cytochromes P450 (P450s) situated in the endoplasmic reticulum (ER), powered by electron transfers from NADPH. Dhurrin is a cyanogenic glucoside and its biosynthesis involves a dynamic metabolon formed by two P450s....... Nevertheless, translocation of the pathway from the ER to the chloroplast creates other difficulties, such as the loss of metabolon formation and intermediate diversion into other metabolic pathways. We show here that co-localization of these enzymes in the thylakoid membrane leads to a significant increase...... in product formation, with a concomitant decrease in off-pathway intermediates. This was achieved by exchanging the membrane anchors of the dhurrin pathway enzymes to components of the Twin-arginine translocation pathway, TatB and TatC, which have self-assembly properties. Consequently, we show 5-fold...

Molecular analysis of a thylakoid K+ channel

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-05-01

The work undertaken during the prior granting period sought to use a novel probe to identify and clone plant ion (K) channels. It was also proposed that in vitro biochemical studies of cation transport across purified preparations of thylakoid membrane be employed to characterize a putative K channel in this membrane system. Over the last several years (including those of the previous grant period), an enormous data base of partially-sequenced mRNAs and numerous genomes (including those of plants) has evolved and provides a powerful alternative to this brute-force approach to identify and clone cDNAs ending physiologically important membrane proteins such as channels. The utility of searching genetic databases for relevant sequences, in addition to the difficulty of working with membrane proteins, led to changes in research focus during the prior granting period, and has resulted in the identification of a new class of plant ion channels, which will be the focus of research during the proposed new granting period.

RECOVERY ACT - Thylakoid Assembly and Folded Protein Transport by the Tat Pathway

Energy Technology Data Exchange (ETDEWEB)

Dabney-Smith, Carole [Miami Univ., Oxford, OH (United States)

2016-07-18

Assembly of functional photosystems complete with necessary intrinsic (membrane-bound) and extrinsic proteins requires the function of at least 3 protein transport pathways in thylakoid membranes. Our research focuses on one of those pathways, a unique and essential protein transport pathway found in the chloroplasts of plants, bacteria, and some archaebacteria, the Twin arginine translocation (Tat) system. The chloroplast Tat (cpTat) system is thought to be responsible for the proper location of ~50% of thylakoid lumen proteins, several of which are necessary for proper photosystem assembly, maintenance, and function. Specifically, cpTat systems are unique because they transport fully folded and assembled proteins across ion tight membranes using only three membrane components, Tha4, Hcf106, and cpTatC, and the protonmotive force generated by photosynthesis. Despite the importance of the cpTat system in plants, the mechanism of transport of a folded precursor is not well known. Our long-term goal is to investigate the role protein transport systems have on organelle biogenesis, particularly the assembly of membrane protein complexes in thylakoids of chloroplasts. The objective of this proposal is to correlate structural changes in the membrane-bound cpTat component, Tha4, to the mechanism of translocation of folded-precursor substrates across the membrane bilayer by using a cysteine accessibility and crosslinking approach. Our central hypothesis is that the precursor passes through a proteinaceous pore of assembled Tha4 protomers that have undergone a conformational or topological change in response to transport. This research is predicated upon the observations that Tha4 exists in molar excess in the membrane relative to the other cpTat components; its regulated assembly to the precursor-bound receptor; and our data showing oligomerization of Tha4 into very large complexes in response to transport. Our rationale for these studies is that understanding cp

Supplementation by thylakoids to a high carbohydrate meal decreases feelings of hunger, elevates CCK levels and prevents postprandial hypoglycaemia in overweight women

DEFF Research Database (Denmark)

Stenblom, Eva-Lena; Montelius, Caroline; Östbring, Karolina

2013-01-01

Thylakoids are chlorophyll-containing membranes in chloroplasts that have been isolated from green leaves. It has been previously shown that thylakoids supplemented with a high-fat meal can affect cholecystokinin (CCK), ghrelin, insulin and blood lipids in humans, and can act to suppress food...... intake and prevent body weight gain in rodents. This study investigates the addition of thylakoids to a high carbohydrate meal and its effects upon hunger motivation and fullness, and the levels of glucose, insulin, CCK, ghrelin and tumour necrosis factor (TNF)-alpha in overweight women. Twenty...... moderately overweight female subjects received test meals on three different occasions; two thylakoid enriched and one control, separated by 1 week. The test meals consisted of a high carbohydrate Swedish breakfast, with or without addition of thylakoids. Blood samples and VAS-questionnaires were evaluated...

Quality control of Photosystem II: the mechanisms for avoidance and tolerance of light and heat stresses are closely linked to membrane fluidity of the thylakoids

Directory of Open Access Journals (Sweden)

Yasusi Yamamoto

2016-08-01

Full Text Available When oxygenic photosynthetic organisms are exposed to excessive light and/or heat, Photosystem II is damaged and electron transport is blocked. In these events, reactive oxygen species, endogenous radicals and lipid peroxidation products generated by photochemical reaction and/or heat cause the damage. Regarding light stress, plants first dissipate excessive light energy captured by light-harvesting chlorophyll protein complexes as heat to avoid the hazards, but once light stress is unavoidable, they tolerate the stress by concentrating damage in a particular protein in photosystem II, i.e. the reaction-center binding D1 protein of Photosystem II. The damaged D1 is removed by specific proteases and replaced with a new copy produced through de novo synthesis (reversible photoinhibition. When light intensity becomes extremely high, irreversible aggregation of D1 occurs and thereby D1 turnover is prevented. Once the aggregated products accumulate in Photosystem II complexes, removal of them by proteases is difficult, and irreversible inhibition of Photosystem II takes place (irreversible photoinhibition. Important is that various aspects of both the reversible and irreversible photoinhibition are highly dependent on the membrane fluidity of the thylakoids. Heat stress-induced inactivation of photosystem II is an irreversible process, which may be also affected by the fluidity of the thylakoid membranes. Here I describe why the membrane fluidity is a key to regulate the avoidance and tolerance of Photosystem II on environmental stresses.

[Effect of high magnesium ion concentration on the electron transport rate and proton exchange in thylakoid membranes in higher plants].

Science.gov (United States)

Ignat'ev, A R; Khorobrykh, S A; Ivanov, B N

2001-01-01

The effects of magnesium ion concentration on the rate of electron transport in isolated pea thylakoids were investigated in the pH range from 4.0 up to 8.0. In the absence of magnesium ions in the medium and in the presence of 5 mM MgCl2 in the experiments not only without added artificial acceptors but also with ferricyanide or methylviologen as an acceptor, this rate had a well-expressed maximum at pH 5.0. It was shown that, after depression to minimal values at pH 5.5-6.5, it gradually rose with increasing pH. An increase in magnesium ion concentration up to 20 mM essentially affected the electron transfer rate: it decreased somewhat at pH 4.0-5.0 but increased at higher pH values. At this magnesium ion concentration, the maximum rate was at pH 6.0-6.5 and the minimum, at pH 7.0. Subsequent rise upon increasing pH to 8.0 was expressed more sharply. The influence of high magnesium ion concentration on the rate of electron transport was not observed in the presence of gramicidin D. It was found that without uncoupler, the changes in the electron transfer rate under the influence of magnesium ions correlated to the changes in the first-order rate constant of the proton efflux from thylakoids. It is supposed that the change in the ability of thylakoids to keep protons by the action of magnesium ions is the result of electrostatic interactions of these ions with the charges on the external surface of membranes. A possible role of regulation of the electron transport rate by magnesium ions in vivo is discussed.

Consumption of thylakoid-rich spinach extract reduces hunger, increases satiety and reduces cravings for palatable food in overweight women

OpenAIRE

Stenblom, Eva-Lena; Egecioglu, Emil; Landin-Olsson, Mona; Erlanson-Albertsson, Charlotte

2015-01-01

Green-plant membranes, thylakoids, have previously been found to increase postprandial release of the satiety hormone GLP-1, implicated in reward signaling. The purpose of this study was to investigate how treatment with a single dose of thylakoids before breakfast affects homeostatic as well as hedonic hunger, measured as wanting and liking for palatable food (VAS). We also examined whether treatment effects were correlated to scores for eating behavior. Compared to placebo, intake of thylak...

Towards an understanding of wheat chloroplasts: a methodical investigation of thylakoid proteome.

Science.gov (United States)

Kamal, Abu Hena Mostafa; Cho, Kun; Komatsu, Setsuko; Uozumi, Nobuyuki; Choi, Jong-Soon; Woo, Sun Hee

2012-05-01

We utilized Percoll density gradient centrifugation to isolate and fractionate chloroplasts of Korean winter wheat cultivar cv. Kumgang (Triticum aestivum L.). The resulting protein fractions were separated by one dimensional polyacrylamide gel electrophoresis (1D-PAGE) coupled with LTQ-FTICR mass spectrometry. This enabled us to detect and identify 767 unique proteins. Our findings represent the most comprehensive exploration of a proteome to date. Based on annotation information from the UniProtKB/Swiss-Prot database and our analyses via WoLF PSORT and PSORT, these proteins are localized in the chloroplast (607 proteins), chloroplast stroma (145), thylakoid membrane (342), lumens (163), and integral membranes (166). In all, 67% were confirmed as chloroplast thylakoid proteins. Although nearly complete protein coverage (89% proteins) has been accomplished for the key chloroplast pathways in wheat, such as for photosynthesis, many other proteins are involved in regulating carbon metabolism. The identified proteins were assigned to 103 functional categories according to a classification system developed by the iProClass database and provided through Protein Information Resources. Those functions include electron transport, energy, cellular organization and biogenesis, transport, stress responses, and other metabolic processes. Whereas most of these proteins are associated with known complexes and metabolic pathways, about 13% of the proteins have unknown functions. The chloroplast proteome contains many proteins that are localized to the thylakoids but as yet have no known function. We propose that some of these familiar proteins participate in the photosynthetic pathway. Thus, our new and comprehensive protein profile may provide clues for better understanding that photosynthetic process in wheat.

Modeling the light-induced electric potential difference (ΔΨ), the pH difference (ΔpH) and the proton motive force across the thylakoid membrane in C3 leaves.

Science.gov (United States)

Lyu, Hui; Lazár, Dušan

2017-01-21

A model was constructed which includes electron transport (linear and cyclic and Mehler type reaction) coupled to proton translocation, counter ion movement, ATP synthesis, and Calvin-Benson cycle. The focus is on modeling of the light-induced total electric potential difference (ΔΨ) which in this model originates from the bulk phase electric potential difference (ΔΨ b ), the localized electric potential difference (ΔΨ c ), as well as the surface electric potential difference (ΔΨ s ). The measured dual wavelength transmittance signal (ΔA515-560nm, electrochromic shift) was used as a proxy for experimental ΔΨ. The predictions for theoretical ΔΨ vary with assumed contribution of ΔΨ s , which might imply that the measured ΔA515-560nm trace on a long time scale reflects the interplay of the ΔΨ components. Simulations also show that partitioning of proton motive force (pmf) to ΔΨ b and ΔpH components is sensitive to the stoichiometric ratio of H + /ATP, energy barrier for ATP synthesis, ionic strength, buffer capacity and light intensity. Our model shows that high buffer capacity promotes the establishment of ΔΨ b , while the formation of pH i minimum is not 'dissipated' but 'postponed' until it reaches the same level as that for low buffer capacity. Under physiologically optimal conditions, the output of the model shows that at steady state in light, the ΔpH component is the main contributor to pmf to drive ATP synthesis while a low ΔΨ b persists energizing the membrane. Our model predicts 11mV as the resting electric potential difference across the thylakoid membrane in dark. We suggest that the model presented in this work can be integrated as a module into a more comprehensive model of oxygenic photosynthesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phylogenetic analysis of the thylakoid ATP/ADP carrier reveals new insights into its function restricted to green plants

Directory of Open Access Journals (Sweden)

Cornelia eSpetea

2012-01-01

Full Text Available ATP is the common energy currency of cellular metabolism in all living organisms. Most of them synthesize ATP in the cytosol or on the mitochondrial inner membrane, whereas land plants, algae and cyanobacteria also produce it on the thylakoid membrane during the light-dependent reactions of photosynthesis. From the site of synthesis, ATP is transported to the site of utilization via intracellular membranes transporters. One major type of ATP transporter is represented by the mitochondrial ADP/ATP carrier family. Here we review a recently characterized member, namely the thylakoid ATP/ADP carrier from Arabidopsis thaliana (AtTAAC. Thus far, no orthologues of this carrier have been characterized in other organisms, although similar sequences can be recognized in many sequenced genomes. Protein Sequence database searches and phylogenetic analyses indicate the absence of TAAC in cyanobacteria and its appearance early in the evolution of photosynthetic eukaryotes. The TAAC clade is composed of carriers found in land plants and some green algae, but no proteins from other photosynthetic taxa, such as red algae, brown algae and diatoms. This implies that TAAC-like sequences arose only once before the divergence of green algae and land plants. Based on these findings, it is proposed that TAAC may have evolved in response to the need of a new activity in higher photosynthetic eukaryotes. This activity may provide the energy to drive reactions during biogenesis and turnover of photosynthetic complexes, which are heterogenously distributed in a thylakoid membrane system composed of appressed and non-appressed regions.

The Arabidopsis thylakoid chloride channel AtCLCe functions in chloride homeostasis and regulation of photosynthetic electron transport

Directory of Open Access Journals (Sweden)

Andrei eHerdean

2016-02-01

Full Text Available Chloride ions can be translocated across cell membranes through Cl− channels or Cl−/H+ exchangers. The thylakoid-located member of the Cl− channel CLC family in Arabidopsis thaliana (AtCLCe was hypothesized to play a role in photosynthetic regulation based on the initial photosynthetic characterization of clce mutant lines. The reduced nitrate content of Arabidopsis clce mutants suggested a role in regulation of plant nitrate homeostasis. In this study, we aimed to further investigate the role of AtCLCe in the regulation of ion homeostasis and photosynthetic processes in the thylakoid membrane. We report that the size and composition of proton motive force were mildly altered in two independent Arabidopsis clce mutant lines. Most pronounced effects in the clce mutants were observed on the photosynthetic electron transport of dark-adapted plants, based on the altered shape and associated parameters of the polyphasic OJIP kinetics of chlorophyll a fluorescence induction. Other alterations were found in the kinetics of state transition and in the macro-organisation of photosystem II supercomplexes, as indicated by circular dichroism measurements. Pre-treatment with KCl but not with KNO3 restored the wild-type photosynthetic phenotype. Analyses by transmission electron microscopy revealed a bow-like arrangement of the thylakoid network and a large thylakoid-free stromal region in chloroplast sections from the dark-adapted clce plants. Based on these data, we propose that AtCLCe functions in Cl− homeostasis after transition from light to dark, which affects chloroplast ultrastructure and regulation of photosynthetic electron transport.

Protection of thylakoids against combined light and drought by a lumenal substance in the resurrection plant Haberlea rhodopensis

Science.gov (United States)

Georgieva, Katya; Sárvári, Éva; Keresztes, Áron

2010-01-01

Background and Aims Haberlea rhodopensis is a perennial, herbaceous, saxicolous, poikilohydric flowering plant that is able to survive desiccation to air-dried state under irradiance below 30 µmol m−2 s−1. However, desiccation at irradiance of 350 µmol m−2 s−1 induced irreversible changes in the photosynthetic apparatus, and mature leaves did not recover after rehydration. The aim here was to establish the causes and mechanisms of irreversible damage of the photosynthetic apparatus due to dehydration at high irradiance, and to elucidate the mechanisms determining recovery. Methods Changes in chloroplast structure, CO2 assimilation, chlorophyll fluorescence parameters, fluorescence imaging and the polypeptide patterns during desiccation of Haberlea under medium (100 µmol m−2 s−1; ML) irradiance were compared with those under low (30 µmol m−2 s−1; LL) irradiance. Key Results Well-watered plants (control) at 100 µmol m−2 s−1 were not damaged. Plants desiccated at LL or ML had similar rates of water loss. Dehydration at ML decreased the quantum efficiency of photosystem II photochemistry, and particularly the CO2 assimilation rate, more rapidly than at LL. Dehydration induced accumulation of stress proteins in leaves under both LL and ML. Photosynthetic activity and polypeptide composition were completely restored in LL plants after 1 week of rehydration, but changes persisted under ML conditions. Electron microscopy of structural changes in the chloroplast showed that the thylakoid lumen is filled with an electron-dense substance (dense luminal substance, DLS), while the thylakoid membranes are lightly stained. Upon dehydration and rehydration the DLS thinned and disappeared, the time course largely depending on the illumination: whereas DLS persisted during desiccation and started to disappear during late recovery under LL, it disappeared from the onset of dehydration and later was completely lost under ML. Conclusions Accumulation of DLS

Damage to photosystem II due to heat stress without light-driven electron flow: involvement of enhanced introduction of reducing power into thylakoid membranes.

Science.gov (United States)

Marutani, Yoko; Yamauchi, Yasuo; Kimura, Yukihiro; Mizutani, Masaharu; Sugimoto, Yukihiro

2012-08-01

Under a moderately heat-stressed condition, the photosystems of higher plants are damaged in the dark more easily than they are in the presence of light. To obtain a better understanding of this heat-derived damage mechanism that occurs in the dark, we focused on the involvement of the light-independent electron flow that occurs at 40 °C during the damage. In various plant species, the maximal photochemical quantum yield of photosystem (PS) II (Fv/Fm) decreased as a result of heat treatment in the dark. In the case of wheat, the most sensitive plant species tested, both Fv/Fm and oxygen evolution rapidly decreased by heat treatment at 40 °C for 30 min in the dark. In the damage, specific degradation of D1 protein was involved, as shown by immunochemical analysis of major proteins in the photosystem. Because light canceled the damage to PSII, the light-driven electron flow may play a protective role against PSII damage without light. Light-independent incorporation of reducing power from stroma was enhanced at 40 °C but not below 35 °C. Arabidopsis mutants that have a deficit of enzymes which mediate the incorporation of stromal reducing power into thylakoid membranes were tolerant against heat treatment at 40 °C in the dark, suggesting that the reduction of the plastoquinone pool may be involved in the damage. In conclusion, the enhanced introduction of reducing power from stroma into thylakoid membranes that occurs around 40 °C causes over-reduction of plastoquinone, resulting in the damage to D1 protein under heat stress without linear electron flow.

Consumption of thylakoid-rich spinach extract reduces hunger, increases satiety and reduces cravings for palatable food in overweight women.

Science.gov (United States)

Stenblom, Eva-Lena; Egecioglu, Emil; Landin-Olsson, Mona; Erlanson-Albertsson, Charlotte

2015-08-01

Green-plant membranes, thylakoids, have previously been found to increase postprandial release of the satiety hormone GLP-1, implicated in reward signaling. The purpose of this study was to investigate how treatment with a single dose of thylakoids before breakfast affects homeostatic as well as hedonic hunger, measured as wanting and liking for palatable food (VAS). We also examined whether treatment effects were correlated to scores for eating behavior. Compared to placebo, intake of thylakoids significantly reduced hunger (21% reduction, p snacks and sweets during the day (36% reduction, p snacks, respectively, and decreased subjective liking for sweet (28% reduction, p snacks, sweet-and-fat snacks in particular, were positively correlated to higher emotional eating scores (p obesity. Individuals scoring higher for emotional eating behavior may have enhanced treatment effect on cravings for palatable food. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

From isolated light-harvesting complexes to the thylakoid membrane: a single-molecule perspective

Science.gov (United States)

Gruber, J. Michael; Malý, Pavel; Krüger, Tjaart P. J.; Grondelle, Rienk van

2018-01-01

The conversion of solar radiation to chemical energy in plants and green algae takes place in the thylakoid membrane. This amphiphilic environment hosts a complex arrangement of light-harvesting pigment-protein complexes that absorb light and transfer the excitation energy to photochemically active reaction centers. This efficient light-harvesting capacity is moreover tightly regulated by a photoprotective mechanism called non-photochemical quenching to avoid the stress-induced destruction of the catalytic reaction center. In this review we provide an overview of single-molecule fluorescence measurements on plant light-harvesting complexes (LHCs) of varying sizes with the aim of bridging the gap between the smallest isolated complexes, which have been well-characterized, and the native photosystem. The smallest complexes contain only a small number (10-20) of interacting chlorophylls, while the native photosystem contains dozens of protein subunits and many hundreds of connected pigments. We discuss the functional significance of conformational dynamics, the lipid environment, and the structural arrangement of this fascinating nano-machinery. The described experimental results can be utilized to build mathematical-physical models in a bottom-up approach, which can then be tested on larger in vivo systems. The results also clearly showcase the general property of biological systems to utilize the same system properties for different purposes. In this case it is the regulated conformational flexibility that allows LHCs to switch between efficient light-harvesting and a photoprotective function.

Comparative study of thylakoid membranes in terminal heterocysts and vegetative cells from two cyanobacteria, Rivularia M-261 and Anabaena variabilis, by fluorescence and absorption spectral microscopy.

Science.gov (United States)

Nozue, Shuho; Katayama, Mitsunori; Terazima, Masahide; Kumazaki, Shigeichi

2017-09-01

Heterocyst is a nitrogen-fixing cell differentiated from a cell for oxygen-evolving photosynthesis (vegetative cell) in some filamentous cyanobacteria when fixed nitrogen (e.g., ammonia and nitrate) is limited. Heterocysts appear at multiple separated positions in a single filament with an interval of 10-20 cells in some genera (including Anabaena variabilis). In other genera, a single heterocyst appears only at the basal terminal in a filament (including Rivularia M-261). Such morphological diversity may necessitate different properties of heterocysts. However, possible differences in heterocysts have largely remained unexplored due to the minority of heterocysts among major vegetative cells. Here, we have applied spectroscopic microscopy to Rivularia and A. variabilis to analyze their thylakoid membranes in individual cells. Absorption and fluorescence spectral imaging enabled us to estimate concentrations and interconnections of key photosynthetic components like photosystem I (PSI), photosystem II (PSII) and subunits of light-harvesting phycobilisome including phycocyanin (PC). The concentration of PC in heterocysts of Rivularia is far higher than that of A. variabilis. Fluorescence quantum yield of PC in Rivularia heterocysts was found to be virtually the same as those in its vegetative cells, while fluorescence quantum yield of PC in A. variabilis heterocysts was enhanced in comparison with its vegetative cells. PSI concentration in the thylakoid membranes of heterocysts seems to remain nearly the same as those of the vegetative cells in both the species. The average stoichiometric ratio between PSI monomer and PC hexamer in Rivularia heterocysts is estimated to be about 1:1. Copyright © 2017 Elsevier B.V. All rights reserved.

Surface density and volume density measurements of chloroplast thylakoids in maize ( Zea mays L.) under chilling conditions

Czech Academy of Sciences Publication Activity Database

Kubínová, Lucie; Kutík, J.

2007-01-01

Roč. 45, č. 4 (2007), s. 481-488 ISSN 0300-3604 R&D Projects: GA AV ČR(CZ) IAA100110502; GA MŠk(CZ) LC06063 Grant - others:GA ČR(CZ) GA522/01/0846 Institutional research plan: CEZ:AV0Z50110509 Keywords : stereology * surface area * thylakoid membranes Subject RIV: EA - Cell Biology Impact factor: 0.976, year: 2007

JUMPING MODE ATOMIC FORCE MICROSCOPY ON GRANA MEMBRANES FROM SPINACH

NARCIS (Netherlands)

Sznee, K.; Dekker, J.P.; Dame, R.T.; Van Roon, H.; Wuite, G.J.L.; Frese, R.N.

2011-01-01

The thylakoid membrane system is a complex membrane system that organizes and reorganizes itself to provide plants optimal chemical energy from sunlight under different and varying environmental conditions. Grana membranes are part of this system and contain the light-driven water-splitting enzyme

A fluorescence detected magnetic resonance investigation of the carotenoid triplet states associated with Photosystem II of isolated spinach thylakoid membranes

CERN Document Server

Santabarbara, S; Carbonera, D; Heathcote, P

2005-01-01

The carotenoid triplet populations associated with the fluorescence emission chlorophyll forms of Photosystem II have been investigated in isolated spinach thylakoid membranes by means of fluorescence detected magnetic resonance in zero field (FDMR). The spectra collected in the 680-690 nm emission range, have been fitted by a global analysis procedure. At least five different carotenoid triplet states coupled to the terminal emitting chlorophyll forms of PS II, peaking at 682 nm, 687 nm and 692 nm, have been characterised. The triplets associated with the outer antenna emission forms, at 682 nm, have zero field splitting parameters D = 0.0385 cm/sup -1/, E = 0.00367 cm/sup -1/; D = 0.0404 cm/sup -1/, E = 0.00379 cm/sup -1/ and D = 0.0386 cm/sup -1/, E = 0.00406 cm/sup -1/ which are very similar to those previously reported for the xanthophylls of the isolated LHC II complex. Therefore the FDMR spectra recorded in this work provide insights into the organisation of the LHC II complex in the unperturbed enviro...

Progress in herbicide determination with the thylakoid bioassay.

Science.gov (United States)

Trapmann, S; Etxebarria, N; Schnabl, H; Grobecker, K H

1998-01-01

Chloroplast thylakoids are used as biological units to determine herbicides in different kinds of water samples as well as in aqueous extracts of compost, soil or food samples. The thylakoid bioassay shows clearly inhibition of fluorescence yield in the presence of photosystem II specific herbicides. Due to this method the ecotoxicological effect of samples with unknown pollutants can be tested fast and cost effective. It has been proven that all photosynthetic active compounds are recorded at the same time because only additive interactions occur. Therefore, the contamination level can be expressed as cumulative parameter for photosystem II active substances. Application was improved clearly by the addition of the radical scavenger sodium ascorbate to the isolation media and by a higher concentration of the measuring medium. A new data evaluation method is described yielding in a lower detection limit of 0.4 microg diuron/1. The guidelines for the quality of water for human consumption with an allowable concentration of pesticides in groups is 0,5 microg/1 and can be controlled with the thylakoid bioassay without performing any preconcentration steps.

Multilayer gyroid cubic membrane organization in green alga Zygnema.

Science.gov (United States)

Zhan, Ting; Lv, Wenhua; Deng, Yuru

2017-09-01

Biological cubic membranes (CM), which are fluid membranes draped onto the 3D periodic parallel surface geometries with cubic symmetry, have been observed within subcellular organelles, including mitochondria, endoplasmic reticulum, and thylakoids. CM transition tends to occur under various stress conditions; however, multilayer CM organizations often appear associated with light stress conditions. This report is about the characterization of a projected gyroid CM in a transmission electron microscopy study of the chloroplast membranes within green alga Zygnema (LB923) whose lamellar form of thylakoid membrane started to fold into multilayer gyroid CM in the culture at the end of log phase of cell growth. Using the techniques of computer simulation of transmission electron microscopy (TEM) and a direct template matching method, we show that these CM are based on the gyroid parallel surfaces. The single, double, and multilayer gyroid CM morphologies are observed in which space is continuously divided into two, three, and more subvolumes by either one, two, or several parallel membranes. The gyroid CM are continuous with varying amount of pseudo-grana with lamellar-like morphology. The relative amount and order of these two membrane morphologies seem to vary with the age of cell culture and are insensitive to ambient light condition. In addition, thylakoid gyroid CM continuously interpenetrates the pyrenoid body through stalk, bundle-like, morphologies. Inside the pyrenoid body, the membranes re-folded into gyroid CM. The appearance of these CM rearrangements due to the consequence of Zygnema cell response to various types of environmental stresses will be discussed. These stresses include nutrient limitation, temperature fluctuation, and ultraviolet (UV) exposure.

Research on the ultrafast fluorescence property of thylakoid membranes of the wild-type and mutant rice

Science.gov (United States)

Ren, Zhao-Yu; Xu, Xiao-Ming; Wang, Shui-Cai; Xin, Yue-Yong; He, Jun-Fang; Hou, Xun

2003-10-01

A high yielding rice variety mutant (Oryza sativa L., Zhenhui 249) with low chlorophyll b (Chl b) has been discovered in natural fields. It has a quality character controlled by a pair of recessive genes (nuclear gene). The partial loss of Chl b in content affects the efficiency of light harvest in a light harvest complex (LHC), thus producing the difference of the exciting energy transfer and the efficiency of photochemistry conversion between the mutant and wild-type rice in photosynthetic unit. The efficiency of utilizing light energy is higher in the mutant than that in the wild-type rice relatively. For further discussion of the above-mentioned difference and learning about the mechanism of the increase in the photochemical efficiency of the mutant, the pico-second resolution fluorescence spectrum measurement with delay-frame-scanning single photon counting technique is adopted. Thylakoid membranes of the mutant and the wild-type rice are excited by an Ar+ laser with a pulse width of 120 ps, repetition rate of 4 MHz and wavelength of 514 nm. Compared with the time and spectrum property of exciting fluorescence, conclusions of those ultrafast dynamic experiments are: 1) The speeds of the exciting energy transferred in photo-system I are faster than that in photo-system II in both samples. 2) The speeds of the exciting energy transfer of mutant sample are faster than those of the wild-type. This might be one of the major reasons why the efficiency of photosynthesis is higher in mutant than that in the wild-type rice.

Energía mareomotriz: potencial energético y medio ambiente

Directory of Open Access Journals (Sweden)

Julián Rodrigo Quintero González

2015-07-01

Full Text Available La energía mareomotriz ha tenido un gran desarrollo en relación a su potencial energético y el estudio de sus impactos ambientales. Este trabajo presenta una perspectiva acerca de estos dos aspectos que han sido ampliamente evaluados en diferentes países. Se concluye que el potencial energético de la energía mareomotriz es significativo, en relación con las capacidades instaladas de las plantas de energía actualmente en operación, con el incremento de la producción energética anual y con el número de nuevos proyectos en el marco global. Se indica también que existen impactos ambientales moderados con su implementación.

Reversible membrane reorganizations during photosynthesis in vivo: revealed by small-angle neutron scattering

DEFF Research Database (Denmark)

Nagy, Gergely; Posselt, Dorthe; Kovacs, Laszlo

2011-01-01

In the present study, we determined characteristic repeat distances of the photosynthetic membranes in living cyanobacterial and eukaryotic algal cells, and in intact thylakoid membranes isolated from higher plants with time-resolved small-angle neutron scattering. This non-invasive technique...

Photosynthetic electron transport in thylakoid preparations from two marine red algae (Rhodophyta).

Science.gov (United States)

Stewart, A C; Larkum, A W

1983-01-01

Thylakoid membrane preparations active in photosynthetic electron transport have been obtained from two marine red algae, Griffithsia monilis and Anotrichium tenue. High concentrations (0.5-1.0 M) of salts such as phosphate, citrate, succinate and tartrate stabilized functional binding of phycobilisomes to the membrane and also stabilized Photosystem II-catalysed electron-transport activity. High concentrations (1.0 M) of chloride and nitrate, or 30 mM-Tricine/NaOH buffer (pH 7.2) in the absence of salts, detached phycobilisomes and inhibited electron transport through Photosystem II. The O2-evolving system was identified as the electron-transport chain component that was inhibited under these conditions. Washing membranes with buffers containing 1.0-1.5 M-sorbitol and 5-50 mM concentrations of various salts removed the outer part of the phycobilisome but retained 30-70% of the allophycocyanin 'core' of the phycobilisome. These preparations were 30-70% active in O2 evolution compared with unwashed membranes. In the sensitivity of their O2-evolving apparatus to the composition of the medium in vitro, the red algae resembled blue-green algae and differed from other eukaryotic algae and higher plants. It is suggested that an environment of structured water may be essential for the functional integrity of Photosystem II in biliprotein-containing algae. PMID:6860312

Hacking the thylakoid proton motive force for improved photosynthesis: modulating ion flux rates that control proton motive force partitioning into Δψ and ΔpH.

Science.gov (United States)

Davis, Geoffry A; Rutherford, A William; Kramer, David M

2017-09-26

There is considerable interest in improving plant productivity by altering the dynamic responses of photosynthesis in tune with natural conditions. This is exemplified by the 'energy-dependent' form of non-photochemical quenching ( q E ), the formation and decay of which can be considerably slower than natural light fluctuations, limiting photochemical yield. In addition, we recently reported that rapidly fluctuating light can produce field recombination-induced photodamage (FRIP), where large spikes in electric field across the thylakoid membrane (Δ ψ ) induce photosystem II recombination reactions that produce damaging singlet oxygen ( 1 O 2 ). Both q E and FRIP are directly linked to the thylakoid proton motive force ( pmf ), and in particular, the slow kinetics of partitioning pmf into its ΔpH and Δ ψ components. Using a series of computational simulations, we explored the possibility of 'hacking' pmf partitioning as a target for improving photosynthesis. Under a range of illumination conditions, increasing the rate of counter-ion fluxes across the thylakoid membrane should lead to more rapid dissipation of Δ ψ and formation of ΔpH. This would result in increased rates for the formation and decay of q E while resulting in a more rapid decline in the amplitudes of Δ ψ -spikes and decreasing 1 O 2 production. These results suggest that ion fluxes may be a viable target for plant breeding or engineering. However, these changes also induce transient, but substantial mismatches in the ATP : NADPH output ratio as well as in the osmotic balance between the lumen and stroma, either of which may explain why evolution has not already accelerated thylakoid ion fluxes. Overall, though the model is simplified, it recapitulates many of the responses seen in vivo , while spotlighting critical aspects of the complex interactions between pmf components and photosynthetic processes. By making the programme available, we hope to enable the community of photosynthesis

Dietary green-plant thylakoids decrease gastric emptying and gut transit, promote changes in the gut microbial flora, but does not cause steatorrhea

DEFF Research Database (Denmark)

Stenblom, Eva-Lena; Weström, Björn R.; Linninge, Caroline

2016-01-01

Green-plant thylakoids increase satiety by affecting appetite hormones such as ghrelin, cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1). The objective of this study was to investigate if thylakoids also affect gastrointestinal (GI) passage and microbial composition. To analyse the effects......, and specifically the Bacteriodes fragilis group, were increased by thylakoid treatment versus placebo, while thylakoids did not cause steatorrhea. Dietary supplementation with thylakoids thus affects satiety both via appetite hormones and GI fullness, and affects the microbial composition without causing GI...... adverse effects such as steatorrhea. This suggests thylakoids as a novel agent in prevention and treatment of obesity....

Ultrastructural changes in the membrane system of isolated chloroplasts of spinach under the influence of carbonic anhydrase inhibitors AA and EA

Directory of Open Access Journals (Sweden)

Marina V. Vodka

2013-04-01

Full Text Available The effects of carbonic anhydrase inhibitors (АА and EA on the membrane system of isolated chloroplasts of spinach were investigated. Under the influence of AA the considerable alterations in granal structure occurred, the thickness of the granal thylakoids increased by 36% and the interspace between thylakoids by 10% comparable with the control. As a result of EA treatment, the thickness of granal thylakoids enhanced by 31% and the interspace between thylakoids increased by 8% in comparison to the control. It was shown that structure of the granal system of the chloroplast was more sensitive to AA than EA. The data obtained can indicate a decrease in the activity of the thylakoid carbonic anhydrase, inhibition of electron transport and photosynthetic process as a whole in the presence of carbonic anhydrase inhibitors (AA and EA.

Structure and membrane organization of photosystem II in green plants

NARCIS (Netherlands)

Hankamer, B; Barber, J; Boekema, EJ

1997-01-01

Photosystem II (PSII) is the pigment protein complex embedded in the thylakoid membrane of higher plants, algae, and cyanobacteria that uses solar energy to drive the photosynthetic water-splitting reaction. This chapter reviews the primary, secondary, tertiary, and quaternary structures of PSII as

Impact of in vitro cultivation conditions on stress responses and on changes in thylakoid membrane proteins and pigments of tobacco during ex vitro acclimation

Czech Academy of Sciences Publication Activity Database

Hofman, Petr; Haisel, Daniel; Komenda, J.; Vágner, Martin; Tichá, I.; Schäfer, C.; Čapková, Věra

2002-01-01

Roč. 45, č. 2 (2002), s. 189-195 ISSN 0006-3134 R&D Projects: GA MŠk OC 843.50; GA AV ČR IAA5038207 Institutional research plan: CEZ:AV0Z5038910 Keywords : thylakoid * proteins * tobacco Subject RIV: EF - Botanics Impact factor: 0.583, year: 2002

Kinetics of structural reorganizations in multilamellarphotosynthetic membranes monitored by small-angle neutronscattering

DEFF Research Database (Denmark)

Nagy, Gergely; Kovacs, Laszlo; Unnep, Renata

2013-01-01

and in unicellular organisms, we discuss the advantages and technical and methodological limitations of timeresolved SANS. We present a detailed and more systematical investigation of the kinetics of light-induced structural reorganizations in isolated spinach thylakoid membranes, which show how changes...

Fine structure of granal thylakoid membrane organization using cryo electron tomography

NARCIS (Netherlands)

Kouril, Roman; Oostergetel, Gert T.; Boekema, Egbert J.

The architecture of grana membranes from spinach chloroplasts was studied by cryo electron tomography. Tomographic reconstructions of ice-embedded isolated grana stacks enabled to resolve features of photosystem II (PSII) in the native membrane and to assign the absolute orientation of individual

Dietary thylakoids suppress blood glucose and modulate appetite-regulating hormones in pigs exposed to oral glucose tolerance test

DEFF Research Database (Denmark)

Montelius, Caroline; Szwiec, Katarzyna; Kardas, Marek

2014-01-01

BACKGROUND & AIMS: Dietary chloroplast thylakoids have previously been found to reduce food intake and body weight in animal models, and to change metabolic profiles in humans in mixed-food meal studies. The aim of this study was to investigate the modulatory effects of thylakoids on glucose...... metabolism and appetite-regulating hormones during an oral glucose tolerance test in pigs fed a high fat diet. METHODS: Six pigs were fed a high fat diet (36 energy% fat) for one month before oral glucose tolerance test (1 g/kg d-glucose) was performed. The experiment was designed as a cross-over study......, either with or without addition of 0.5 g/kg body weight of thylakoid powder. RESULTS: The supplementation of thylakoids to the oral glucose tolerance test resulted in decreased blood glucose concentrations during the first hour, increased plasma cholecystokinin concentrations during the first two hours...

Characterization of the cytochrome c oxidase in isolated and purified plasma membranes from the cyanobacterium Anacystis nidulans

International Nuclear Information System (INIS)

Peschek, G.A.; Wastyn, M.; Trnka, M.; Molitor, V.; Fry, I.V.; Packer, L.

1989-01-01

Functionally intact plasma membranes were isolated from the cyanobacterium (blue-green alga) Anacystis nidulans through French pressure cell extrusion of lysozyme/EDTA-treated cells, separated from thylakoid membranes by discontinuous sucrose density gradient centrifugation, and purified by repeated recentrifugation. Origin and identity of the chlorophyll-free plasma membrane fraction were confirmed by labeling of intact cells with impermeant protein markers, [ 35 S]diazobenzenesulfonate and fluorescamine, prior to membrane isolation. Rates of oxidation of reduced horse heart cytochrome c by purified plasma and thylakoid membranes were 90 and 2 nmol min -1 (mg of protein) -1 , respectively. The cytochrome oxidase in isolated plasma membranes was identified as a copper-containing aa 3 -type enzyme from the properties of its redox-active and EDTA-resistant Cu 2+ ESR signal, the characteristic inhibition profile, reduced minus oxidized difference spectra, carbon monoxide difference spectra, photoaction and photodissociation spectra of the CO-inhibited enzyme, and immunological cross-reaction of two subunits of the enzyme with antibodies against subunits I and II, and the holoenzyme, of Paracoccus denitrificans aa 3 -type cytochrome oxidase. The data presented are the first comprehensive evidence for the occurrence of aa 3 -type cytochrome oxidase in the plasma membrane of a cyanobacterium similar to the corresponding mitochondrial enzyme

Reconstitution of CF1-depleted thylakoid membranes with complete and fragmented chloroplast ATPase. The role of the delta subunit for proton conduction through CF0

NARCIS (Netherlands)

Engelbrecht, Siegfried; Lill, H; Junge, Wolfgang

1986-01-01

Chloroplast ATPase (CF1) was isolated from spinach, pea and maize thylakoids by EDTA extraction followed by anion-exchange chromatography. CF1 was purified and resolved by HPLC into integral CF1, and CF1 lacking the delta & epsilon subunits: CF1(-delta) and CF1(-epsilon). Washing Mono-Q-bound CF1

Energía financiera

OpenAIRE

Altuve G., José G.

2016-01-01

La energía financiera surge como consecuencia de la unión de los conceptos energía y financiera. La primera, como la acción a seguir en un momento del tiempo, y la segunda vinculada al manejo de variables tales como: Estructura financiera y su costo de capital y, las decisiones de inversión consideradas bajo riesgo. Si se armonizan estos dos aspectos estamos en presencia de la fusión de la energía y la administración financiera en dos de sus variables más importantes. Financial power arise...

Flip-flop of phospholipids in proteoliposomes reconstituted from detergent extract of chloroplast membranes: kinetics and phospholipid specificity.

Directory of Open Access Journals (Sweden)

Archita Rajasekharan

Full Text Available Eukaryotic cells are compartmentalized into distinct sub-cellular organelles by lipid bilayers, which are known to be involved in numerous cellular processes. The wide repertoire of lipids, synthesized in the biogenic membranes like the endoplasmic reticulum and bacterial cytoplasmic membranes are initially localized in the cytosolic leaflet and some of these lipids have to be translocated to the exoplasmic leaflet for membrane biogenesis and uniform growth. It is known that phospholipid (PL translocation in biogenic membranes is mediated by specific membrane proteins which occur in a rapid, bi-directional fashion without metabolic energy requirement and with no specificity to PL head group. A recent study reported the existence of biogenic membrane flippases in plants and that the mechanism of plant membrane biogenesis was similar to that found in animals. In this study, we demonstrate for the first time ATP independent and ATP dependent flippase activity in chloroplast membranes of plants. For this, we generated proteoliposomes from Triton X-100 extract of intact chloroplast, envelope membrane and thylakoid isolated from spinach leaves and assayed for flippase activity using fluorescent labeled phospholipids. Half-life time of flipping was found to be 6 ± 1 min. We also show that: (a intact chloroplast and envelope membrane reconstituted proteoliposomes can flip fluorescent labeled analogs of phosphatidylcholine in ATP independent manner, (b envelope membrane and thylakoid reconstituted proteoliposomes can flip phosphatidylglycerol in ATP dependent manner, (c Biogenic membrane ATP independent PC flipping activity is protein mediated and (d the kinetics of PC translocation gets affected differently upon treatment with protease and protein modifying reagents.

Fe deficiency induced changes in rice (Oryza sativa L.) thylakoids.

Science.gov (United States)

Wang, Yuwen; Xu, Chao; Li, Kang; Cai, Xiaojie; Wu, Min; Chen, Guoxiang

2017-01-01

Iron deficiency is an important abiotic stress that limits productivity of crops all over the world. We selected a hybrid rice (Oryza sativa L.), LYPJ, which is super high-yield and widely cultured in China, to investigate changes in the components and structure of thylakoid membranes and photosynthetic performance in response to iron deficiency. Our results demonstrated that photosystem I (PSI) is the primary target for iron deficiency, while the changes in photosystem II (PSII) are important for rebuilding a balance in disrupted energy utilization and dissipation caused by differential degradation of photosynthetic components. The result of immunoblot analysis suggested that the core subunit PsaA declined drastically, while PsbA remained relatively stable. Furthermore, several organizational changes of the photosynthetic apparatus were found by BN-PAGE, including a marked decrease in the PSI core complexes, the Cytb 6 /f complex, and the trimeric form of the LHCII antenna, consistent with the observed unstacking grana. The fluorescence induction analysis indicated a descending PSII activity with energy dissipation enhanced markedly. In addition, we proposed that the crippled CO 2 assimilation could be compensated by the enhanced of phosphoenolpyruvate carboxylase (PEPC), which is suggested by the decreased ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and photosynthetic efficiency.

Novel protein phosphorylation site identification in spinach stroma membranes by titanium dioxide microcolumns and tandem mass spectrometry

DEFF Research Database (Denmark)

Rinalducci, Sara; Larsen, Martin Røssel; Mohammed, Shabaz

2006-01-01

In this work, spinach stroma membrane, instead of thylakoid, has been investigated for the presence of phosphorylated proteins. We identified seven previously unknown phosphorylation sites by taking advantage of TiO(2) phosphopeptides enrichment coupled to mass spectrometric analysis. Upon...

PSB27: A thylakoid protein enabling Arabidopsis to adapt to changing light intensity

Energy Technology Data Exchange (ETDEWEB)

Hou, Xin [Univ. of California, Berkeley, CA (United States). Dept of Plant and Microbial Biology; Garcia, Veder J. [Univ. of California, Berkeley, CA (United States). Dept of Plant and Microbial Biology; Buchanan, Bob B. [Univ. of California, Berkeley, CA (United States). Dept of Plant and Microbial Biology; Luan, Sheng [Univ. of California, Berkeley, CA (United States). Dept of Plant and Microbial Biology

2016-08-22

dissect the mechanism of action for CYP38. Our studies suggest an “autoinhibitory” model for CYP38 action. We plan to test this model and determine the mechanistic details for CYP38 function by biochemical and genetic procedures. 2. To determine the mechanism of action of FKBP20-2/FKBP16-3. Studies on FBKP16-3 and FKBP20-2 suggest that they may work together as a redox-dependent duo in PSII assembly. We will test this hypothesis using biochemical and genetic tools. 3. To determine the function of lumenal FKBPs by multi-gene mutagenesis approach. Using new genetic knockout (KO) procedures especially CRISPR/CAS9 system, we plan to generate multi-gene KO models that will likely provide vital information on those FKBPs with functional redundancy. 4. Functional analysis of thylakoid lumen network. We will focus our effort on objectives 1-3. Objective 4 represents a long-term goal to establish a more comprehensive network of proteins in the thylakoid lumen and their function in the assembly and maintenance of photosynthetic complexes. I hypothesize that the 16 immunophilin-type chaperones and foldases in the thylakoid lumen constitute an “assembly line” for the various components in the photosynthetic electron transport chain. Understanding this assembly line will enable further engineering of more efficient photosynthetic machines to capture more light energy and enhance plant productivity. Furthermore, it is envisioned that such molecular “assembly line” may be rebuilt to produce artificial photosynthesis in vitro or in non-photosynthetic organisms. These are highly relevant to the mission of “Photosynthetic Systems” and “Physical Biosciences” programs to “enhance our understanding of energy capture, conversion, and/or storage.” During the funding period, we have performed a number of experiments under the proposed objectives and obtained several new results. We have found in Objective 1 that CYP38 is associated to the thylokoid membrane with a larger

Energized Oxygen : Speiser Current Sheet Bifurcation

Science.gov (United States)

George, D. E.; Jahn, J. M.

2017-12-01

A single population of energized Oxygen (O+) is shown to produce a cross-tail bifurcated current sheet in 2.5D PIC simulations of the magnetotail without the influence of magnetic reconnection. Treatment of oxygen in simulations of space plasmas, specifically a magnetotail current sheet, has been limited to thermal energies despite observations of and mechanisms which explain energized ions. We performed simulations of a homogeneous oxygen background, that has been energized in a physically appropriate manner, to study the behavior of current sheets and magnetic reconnection, specifically their bifurcation. This work uses a 2.5D explicit Particle-In-a-Cell (PIC) code to investigate the dynamics of energized heavy ions as they stream Dawn-to-Dusk in the magnetotail current sheet. We present a simulation study dealing with the response of a current sheet system to energized oxygen ions. We establish a, well known and studied, 2-species GEM Challenge Harris current sheet as a starting point. This system is known to eventually evolve and produce magnetic reconnection upon thinning of the current sheet. We added a uniform distribution of thermal O+ to the background. This 3-species system is also known to eventually evolve and produce magnetic reconnection. We add one additional variable to the system by providing an initial duskward velocity to energize the O+. We also traced individual particle motion within the PIC simulation. Three main results are shown. First, energized dawn- dusk streaming ions are clearly seen to exhibit sustained Speiser motion. Second, a single population of heavy ions clearly produces a stable bifurcated current sheet. Third, magnetic reconnection is not required to produce the bifurcated current sheet. Finally a bifurcated current sheet is compatible with the Harris current sheet model. This work is the first step in a series of investigations aimed at studying the effects of energized heavy ions on magnetic reconnection. This work differs

Estudio energético del sistema eléctrico en Ecuador. Impulso a la Energía Solar Fotovoltaica

OpenAIRE

Eras Almeida, Andrea Alejandra

2012-01-01

La realización de este proyecto en base a la legislación que promueve el desarrollo de la energía limpia, pretende mostrar los cambios que tendrá la matriz energética del Ecuador si se impone un aporte renovable a la producción de energía y sus beneficios con sus futuros proyectos emblemáticos. Así también, pretende el impulso a la energía solar fotovolataica a nivel de construcciones fijas, con inversión privada y para beneficio de la sociedad misma.

Excitation energy transfer between Light-harvesting complex II and Photosystem I in reconstituted membranes.

Science.gov (United States)

Akhtar, Parveen; Lingvay, Mónika; Kiss, Teréz; Deák, Róbert; Bóta, Attila; Ughy, Bettina; Garab, Győző; Lambrev, Petar H

2016-04-01

Light-harvesting complex II (LHCII), the major peripheral antenna of Photosystem II in plants, participates in several concerted mechanisms for regulation of the excitation energy and electron fluxes in thylakoid membranes. In part, these include interaction of LHCII with Photosystem I (PSI) enhancing the latter's absorption cross-section - for example in the well-known state 1 - state 2 transitions or as a long-term acclimation to high light. In this work we examined the capability of LHCII to deliver excitations to PSI in reconstituted membranes in vitro. Proteoliposomes with native plant thylakoid membrane lipids and different stoichiometric ratios of LHCII:PSI were reconstituted and studied by steady-state and time-resolved fluorescence spectroscopy. Fluorescence emission from LHCII was strongly decreased in PSI-LHCII membranes due to trapping of excitations by PSI. Kinetic modelling of the time-resolved fluorescence data revealed the existence of separate pools of LHCII distinguished by the time scale of energy transfer. A strongly coupled pool, equivalent to one LHCII trimer per PSI, transferred excitations to PSI with near-unity efficiency on a time scale of less than 10ps but extra LHCIIs also contributed significantly to the effective antenna size of PSI, which could be increased by up to 47% in membranes containing 3 LHCII trimers per PSI. The results demonstrate a remarkable competence of LHCII to increase the absorption cross-section of PSI, given the opportunity that the two types of complexes interact in the membrane. Copyright © 2016 Elsevier B.V. All rights reserved.

Energía minihidráulica : una alternativa energética para electrificación rural

OpenAIRE

Agudelo Flórez, Sergio Cipriano; Chamorro Rendón, Luis Javier

2002-01-01

Entre las actividades del Grupo de Energía Alternativa (GEA) de la Facultad de Ingeniería de la Universidad de Antioquia, se pretende el desarrollo de prototipos que aprovechen las fuentes no convencionales para la producción de energía eléctrica y así satisfacer las necesidades insatisfechas de las viviendas rurales aisladas de la red energética nacional. En la región del Oriente antioqueño, se encontró un formidable recurso hidráulico de grandes ríos, quebradas y fuentes de agua cercanas a ...

Free Flow Zonal Electrophoresis for Fractionation of Plant Membrane Compartments Prior to Proteomic Analysis.

Science.gov (United States)

Barkla, Bronwyn J

2018-01-01

Free flow zonal electrophoresis (FFZE) is a versatile, reproducible, and potentially high-throughput technique for the separation of plant organelles and membranes by differences in membrane surface charge. It offers considerable benefits over traditional fractionation techniques, such as density gradient centrifugation and two-phase partitioning, as it is relatively fast, sample recovery is high, and the method provides unparalleled sample purity. It has been used to successfully purify chloroplasts and mitochondria from plants but also, to obtain highly pure fractions of plasma membrane, tonoplast, ER, Golgi, and thylakoid membranes. Application of the technique can significantly improve protein coverage in large-scale proteomics studies by decreasing sample complexity. Here, we describe the method for the fractionation of plant cellular membranes from leaves by FFZE.

Calcium transport in vesicles energized by cytochrome oxidase

Energy Technology Data Exchange (ETDEWEB)

Rosier, Randy N. [Univ. of Rochester, NY (United States)

1979-01-01

Experiments on the reconstitution of cytochrome oxidase into phospholipid vesicles were carried out using techniques of selectivity energizing the suspensions with ascorbate and cytochrome c or ascorbate, PMS, and internally trapped cytochrome c. It was found that the K⁺ selective ionophore valinomycin stimulated the rate of respiration of cytochrome oxidase vesicles regardless of the direction of the K⁺ flux across the vesicle membranes. The stimulation occurred in the presence of protonophoric uncouplers and in the complete absence of potassium or in detergent-lysed suspensions. Gramicidin had similar effects and it was determined that the ionophores acted by specific interaction with cytochrome oxidase rather than by the previously assumed collapse of membrane potentials. When hydrophobic proteins and appropriate coupling factors were incorporated into the cytochrome oxidase, vesicles phosphorylation of ADP could be coupled to the oxidation reaction of cytochrome oxidase. Relatively low P:O, representing poor coupling of the system, were problematical and precluded measurements of protonmotive force. However the system was used to study ion translocation.

El futuro energético de Japón

Directory of Open Access Journals (Sweden)

María Francisca Casado

2016-05-01

Full Text Available Tras el triple desastre del 11 de marzo de 2011, Japón se encuentra en una encrucijada energética. A corto y medio plazo depende de las importaciones de combustibles fósiles para garantizar su seguridad energética, pero el largo plazo está por decidir y lo determinarán las decisiones que tome en estos años. Como consta en su Estrategia de Seguridad Nacional, para Japón la seguridad energética es una cuestión de seguridad nacional. El artículo revisa la trayectoria nuclear nipona, estudia cuáles son los factores que configuran el mercado eléctrico japonés y analiza su actual situación energética. Por otra parte, también repasa los principios que han marcado su política energética, deteniéndose a evaluar los dos últimos Planes Estratégicos de Energía –uno anterior y otro posterior a Fukushima- antes de adentrarse en el debate sobre la composición óptima del futuro mix energético para cumplir con su trilema de la seguridad energética, marcado por su compromiso con el medio ambiente.

Energized Learning

Science.gov (United States)

college-level courses. The site includes lessons and activities that develop specific skills and knowledge that planning for an energy efficient future involves knowledge of science, mathematics, economics and skepticism about their predictive power. At the core of the Energized Leaning site is a interactive web-based

Energía y cambio climático

Directory of Open Access Journals (Sweden)

Wilfredo Bulege Gutiérrez

2014-06-01

Full Text Available Es claro que el crecimiento de la población, la extracción de materiales, la producción alimentaria y el incremento de energía para todas las actividades humanas nos conducen a un estado de colisión con las capacidades de la biosfera y los ecosistemas en el proceso de asegurar la provisión de bienes y servicios indispensables para la vida (1. La producción de energía convencional y contaminante es hoy una de las más graves en este escenario, tanto que la comunidad internacional y las potencias ya han empezado a dar muestras de preocupación por la seguridad energética y, con ello por la amenaza del cambio climático. En el actual cambio climático por primera vez se viene demostrando que la humanidad ha cambiado decisivamente un ciclo liberando CO2 a la atmósfera a través de la quema de combustibles fósiles y cambios en el uso del suelo por más de 500 000 años. El origen del cambio climático se remonta a dos grandes transformaciones en el uso de la energía. En primer lugar, la energía hidráulica fue reemplazada por el carbón, una fuente de energía condensada por la naturaleza a lo largo de millones de años. Fue el aprovechamiento del carbón para nuevas tecnologías lo que propulsó la revolución industrial y desató aumentos sin precedentes en la productividad. La segunda gran transformación ocurrió 150 años más tarde. El petróleo había sido una fuente de energía humana durante milenios. En China, por ejemplo, se registran pozos petroleros ya en el siglo IV. No obstante, la utilización del petróleo para los motores de combustión interna a comienzos del siglo XX marcó el inicio de una revolución en el transporte. La quema de carbón y petróleo, junto con el gas natural, ha transformado a las sociedades humanas al proveerle la energía impulsora de grandes aumentos en la riqueza y la productividad, pero también ha impulsado el cambio climático (2. La economía humana ha crecido vertiginosamente, se multiplic

Propuesta de la certificación energética, mediante simulación dinámica, como herramienta de gestión energética ISO 50001 Versus auditoria energética en edificios.

OpenAIRE

Rey Hernández, Javier María; Rey Hernández, Alberto; Velasco, Eloy; San José, Julio; Rey Martinez, Francisco Javier

2017-01-01

Producción Científica El objetivo es el estudio de la gestión energética ISO 50001, mediante las herramientas de sistema de gestión tales como la auditoría energética y compararlo con la certificación energética mediante simulación dinámica, aplicadas a un edificio universitario estándar. La metodología empleada para alcanzar unos resultados de ahorro y eficiencia energética, aplicados a un edificio universitario, pretenden servir de modelo para poder extrapolarlos a edificios que compo...

Conocimiento de Energía: Principios Esenciales y Conceptos Fundamentales para la Educación de Energía

Energy Technology Data Exchange (ETDEWEB)

None

2014-06-01

This is the Spanish version of our Energy Literacy guidebook. Esta guía presenta conceptos de energía que, cuando se entienden y se aplican, ayudan a individuos y a comunidades a tomar decisiones sobre la energía con conocimiento de causa. No es un currículo sino que ofrece un marco sobre el cual puede basarse un plan de estudios. La guía se dirige a cualquier persona que participe en la educación de energía.

Estudio de la autosuficiencia energética de una vivienda unifamiliar

OpenAIRE

Zeggaf, Itimad

2015-01-01

El título del proyecto es “Estudio de la autosuficiencia energética de una vivienda unifamiliar”. Una vivienda energéticamente autosuficiente no puede depender de ningún tipo de compañía para satisfacer las necesidades energéticas del usuario. Este proyecto estudia las necesidades energéticas de una vivienda unifamiliar habitada por 4 personas, planteando una solución que abastezca sus necesidades energéticas mediante las energías renovables. También se estudia el aprovechamiento del agua ...

The main thylakoid membrane lipid monogalactosyldiacylglycerol (MGDG) promotes the de-epoxidation of violaxanthin associated with the light-harvesting complex of photosystem II (LHCII).

Science.gov (United States)

Schaller, Susann; Latowski, Dariusz; Jemioła-Rzemińska, Małgorzata; Wilhelm, Christian; Strzałka, Kazimierz; Goss, Reimund

2010-03-01

In higher plants, the major part of the xanthophyll cycle pigment violaxanthin (Vx) is non-covalently bound to the main light-harvesting complex of PSII (LHCII). Under saturating light conditions Vx has to be released from its binding site into the surrounding lipid phase, where it is converted to zeaxanthin (Zx) by the enzyme Vx de-epoxidase (VDE). In the present study we investigated the influence of thylakoid lipids on the de-epoxidation of Vx, which was still associated with the LHCII. We isolated LHCII with different concentrations of native, endogenous lipids and Vx by sucrose gradient centrifugation or successive cation precipitation. Analysis of the different LHCII preparations showed that the concentration of LHCII-associated Vx was correlated with the concentration of the main thylakoid lipid monogalactosyldiacylglycerol (MGDG) associated with the complexes. Decreases in the MGDG content of the LHCII led to a diminished Vx concentration, indicating that a part of the total Vx pool was located in an MGDG phase surrounding the LHCII, whereas another part was bound to the LHCII apoproteins. We further studied the convertibility of LHCII-associated Vx in in-vitro enzyme assays by addition of isolated VDE. We observed an efficient and almost complete Vx conversion in the LHCII fractions containing high amounts of endogenous MGDG. LHCII preparations with low concentrations of MGDG exhibited a strongly reduced Vx de-epoxidation, which could be increased by addition of exogenous, pure MGDG. The de-epoxidation of LHCII-associated Vx was saturated at a much lower concentration of native, endogenous MGDG compared with the concentration of isolated, exogenous MGDG, which is needed for optimal VDE activity in in-vitro assays employing pure isolated Vx. Copyright 2009 Elsevier B.V. All rights reserved.

Energía Undimotriz, alternativa para la producción de Energía Eléctrica en la Provincia de Santa Elena

Directory of Open Access Journals (Sweden)

Rolando Calero

2015-10-01

Full Text Available La energía undimotriz, es la energía que permite obtener electricidad a partir de energía mecánica generada por el movimiento de las olas. Es uno de los tipos de energías renovables con más recientes estudios, y presenta enormes ventajas frente a otras energías renovables debido a que se tendría mayor facilidad para predecir condiciones geológicas óptimas que permitan la mayor eficiencia en sus procesos. Debido a que es más fácil llegar a predecir condiciones óptimas de oleaje, en comparación con la obtenida con  los vientos para obtener energía eólica, donde su variabilidad es menor.En este trabajo se espera aportar y dilucidar con datosespecíficos sobre la morfología de la zonamarítima en la provincia de Santa Elena, tratando depredecir si las características propias del lugar son idóneas  para producir electricidad en base a la implementación de energíaundimotriz, como fuente renovable no convencional utilizando las tecnologías actuales para este propósito.

Importancia de las energías renovables en la seguridad energética y su relación con el crecimiento económico.

Directory of Open Access Journals (Sweden)

Lilian Paola Umbarila Valencia

2015-12-01

Full Text Available La creciente demanda de las necesidades sociales a nivel global, impulsada por los hábitos de vida y la forma en la que se organizan las regiones ha llevado al crecimiento paralelo de la industria y con ello al creciente aumento del consumo de energía. Este artículo de investigación reflexiona acerca de la relevancia que tienen las energías renovables para la seguridad energética, teniendo en cuenta la inestabilidad de los precios del petróleo y su influencia en el mercado de los hidrocarburos como fuente primaria de energía. Se evidencian los avances que han tenido las tecnologías de energías renovables a nivel global, regional y local y el rol que juegan en la independencia energética y en la mitigación del impacto ambiental. Se concluye que las naciones deben buscar la optimización de las energías renovables desde los ámbitos: local, regional y global propendiendo por su uso adecuado desde la legislación. El futuro de las energías renovables está dado por la rentabilidad, ya que para que el uso de éstas siga creciendo, deben seguir atrayendo capital lo cual significa que los inversores deben ver una rentabilidad competitiva. Otra recomendación importante es la integración de la energía renovable en la red, incluyendo fuentes de generación intermitentes e incluso imprevisibles. 

Temas de Física para Ingeniería: Trabajo y energía

OpenAIRE

Beléndez, Augusto; Pastor Antón, Carlos; Bernabeu, Guillermo

1988-01-01

Apuntes de Mecánica: "Trabajo y energía". Trabajo y potencia. Energía cinética, teorema de la energía cinética. Fuerzas conservativas, energía potencial. Energía potencial gravitatoria. Principio de conservación de la energía mecánica. Choques.

Membrane Stored Curvature Elastic Stress Modulates Recruitment of Maintenance Proteins PspA and Vipp1.

Science.gov (United States)

McDonald, Christopher; Jovanovic, Goran; Ces, Oscar; Buck, Martin

2015-09-01

Phage shock protein A (PspA), which is responsible for maintaining inner membrane integrity under stress in enterobacteria, and vesicle-inducting protein in plastids 1 (Vipp1), which functions for membrane maintenance and thylakoid biogenesis in cyanobacteria and plants, are similar peripheral membrane-binding proteins. Their homologous N-terminal amphipathic helices are required for membrane binding; however, the membrane features recognized and required for expressing their functionalities have remained largely uncharacterized. Rigorously controlled, in vitro methodologies with lipid vesicles and purified proteins were used in this study and provided the first biochemical and biophysical characterizations of membrane binding by PspA and Vipp1. Both proteins are found to sense stored curvature elastic (SCE) stress and anionic lipids within the membrane. PspA has an enhanced sensitivity for SCE stress and a higher affinity for the membrane than Vipp1. These variations in binding may be crucial for some of the proteins' differing roles in vivo. Assays probing the transcriptional regulatory function of PspA in the presence of vesicles showed that a relief of transcription inhibition occurs in an SCE stress-specific manner. This in vitro recapitulation of membrane stress-dependent transcription control suggests that the Psp response may be mounted in vivo when a cell's inner membrane experiences increased SCE stress. All cell types maintain the integrity of their membrane systems. One widely distributed membrane stress response system in bacteria is the phage shock protein (Psp) system. The central component, peripheral membrane protein PspA, which mitigates inner membrane stress in bacteria, has a counterpart, Vipp1, which functions for membrane maintenance and thylakoid biogenesis in plants and photosynthetic bacteria. Membrane association of both these proteins is accepted as playing a pivotal role in their functions. Here we show that direct membrane binding by

Ferredoxin-dependent and antimycin A-sensitive reduction of cytochrome b-559 by far-red light in maize [Zea mays] thylakoids; participation of a meladiol-reducible cytochrome b-559 in cyclic electron flow

International Nuclear Information System (INIS)

Miyake, C.; Schreiber, U.; Asada, K.

1995-01-01

Thylakoids from mesophyll cells of maize showed a high rate of the ferredoxin (Fd)-dependent and antimycin A (AntiA)-sensitive cyclic electron flow as determined by the quenching of 9-aminoacridine fluorescence which indicates the formation of ΔpH across the membranes. Spectrophotometric survey of the thylakoids showed the reduction of a Cyt having an α-peak at 559 nm [Cyt b-559(Fd)] by far-red light, which depended on Fd and was sensitive to AntiA. Dose dependencies of Fd and AntiA on the photoreduction of Cyt b-559(Fd) were the same as those of the formation of ΔpH. Cyt b-559(Fd) occurred in an oxidized form even in the presence of ascorbate and was reduced by far-red light. In darkness, it was reduced only by menadiol (E m,7 = –10mV). Thus, Cyt b-559(Fd) was distinguished from Cyt b-559 in the PSII complex by its low redox potential. The present results indicate that Cyt b-559(Fd) mediates electron transfer from Fd to plastoquinone during Fd-dependent cyclic electron flow around PSI. (author)

Cosecha de energía

OpenAIRE

García Ojero, Jesús

2016-01-01

En este trabajo se analizarán los distintos métodos conocidos de extraer energía de fuentes tanto naturales como las producidas por el ser humano, entre las que se pueden distinguir las vibraciones mecánicas, gradientes de temperatura o las ondas electromagnéticas emitidas por aparatos electrónicos. Primero realizaremos una revisión bibliográfica de distintos métodos de obtención de energía a partir de vibraciones mecánicas, utilizando materiales piezoeléctricos y actuadores electromagnéticos...

Light-induced modification of plant plasma membrane ion transport.

Science.gov (United States)

Marten, I; Deeken, R; Hedrich, R; Roelfsema, M R G

2010-09-01

Light is not only the driving force for electron and ion transport in the thylakoid membrane, but also regulates ion transport in various other membranes of plant cells. Light-dependent changes in ion transport at the plasma membrane and associated membrane potential changes have been studied intensively over the last century. These studies, with various species and cell types, revealed that apart from regulation by chloroplasts, plasma membrane transport can be controlled by phytochromes, phototropins or channel rhodopsins. In this review, we compare light-dependent plasma membrane responses of unicellular algae (Eremosphaera and Chlamydomonas), with those of a multicellular alga (Chara), liverworts (Conocephalum), mosses (Physcomitrella) and several angiosperm cell types. Light-dependent plasma membrane responses of Eremosphaera and Chara are characterised by the dominant role of K(+) channels during membrane potential changes. In most other species, the Ca(2+)-dependent activation of plasma membrane anion channels represents a general light-triggered event. Cell type-specific responses are likely to have evolved by modification of this general response or through the development of additional light-dependent signalling pathways. Future research to elucidate these light-activated signalling chains is likely to benefit from the recent identification of S-type anion channel genes and proteins capable of regulating these channels.

Thylakoid redox signals are integrated into organellar-gene-expression-dependent retrograde signalling in the prors1-1 mutant

Directory of Open Access Journals (Sweden)

Luca eTadini

2012-12-01

Full Text Available Perturbations in organellar gene expression (OGE and the thylakoid redox state (TRS activate retrograde signalling pathways that adaptively modify nuclear gene expression (NGE, according to developmental and metabolic needs. The prors1-1 mutation in Arabidopsis down-regulates the expression of the nuclear gene Prolyl-tRNA Synthetase1 (PRORS1 which acts in both plastids and mitochondria, thereby impairing protein synthesis in both organelles and triggering OGE-dependent retrograde signalling. Because the mutation also affects thylakoid electron transport, TRS-dependent signals may likewise have an impact on the changes in NGE observed in this genotype. In this study, we have investigated whether signals related to TRS are actually integrated into the OGE-dependent retrograde signalling pathway. To this end, the chaos mutation (for chlorophyll a/b binding protein harvesting-organelle specific, which shows a partial loss of PSII antennae proteins and thus a reduction in PSII light absorption capability, was introduced into the prors1-1 mutant background. The resulting double mutant displayed a prors1-1-like reduction in plastid translation rate and a chaos-like decrease in PSII antenna size, whereas the hyper-reduction of the thylakoid electron transport chain, caused by the prors1-1 mutation, was alleviated, as determined by monitoring chlorophyll (Chl fluorescence and thylakoid phosphorylation. Interestingly, a substantial fraction of the nucleus-encoded photosynthesis genes down-regulated in the prors1-1 mutant are expressed at nearly wild-type rates in prors1-1 chaos leaves, and this recovery is reflected in the steady-state levels of their protein products in the chloroplast. We therefore conclude that signals related to photosynthetic electron transport and TRS, and indirectly to carbohydrate metabolism and energy balance, are indeed fed into the OGE-dependent retrograde pathway to modulate NGE and adjust the abundance of chloroplast proteins.

Consequences of C4 differentiation for chloroplast membrane proteomes in maize mesophyll and bundle sheath cells.

Science.gov (United States)

Majeran, Wojciech; Zybailov, Boris; Ytterberg, A Jimmy; Dunsmore, Jason; Sun, Qi; van Wijk, Klaas J

2008-09-01

Chloroplasts of maize leaves differentiate into specific bundle sheath (BS) and mesophyll (M) types to accommodate C(4) photosynthesis. Chloroplasts contain thylakoid and envelope membranes that contain the photosynthetic machineries and transporters but also proteins involved in e.g. protein homeostasis. These chloroplast membranes must be specialized within each cell type to accommodate C(4) photosynthesis and regulate metabolic fluxes and activities. This quantitative study determined the differentiated state of BS and M chloroplast thylakoid and envelope membrane proteomes and their oligomeric states using innovative gel-based and mass spectrometry-based protein quantifications. This included native gels, iTRAQ, and label-free quantification using an LTQ-Orbitrap. Subunits of Photosystems I and II, the cytochrome b(6)f, and ATP synthase complexes showed average BS/M accumulation ratios of 1.6, 0.45, 1.0, and 1.33, respectively, whereas ratios for the light-harvesting complex I and II families were 1.72 and 0.68, respectively. A 1000-kDa BS-specific NAD(P)H dehydrogenase complex with associated proteins of unknown function containing more than 15 proteins was observed; we speculate that this novel complex possibly functions in inorganic carbon concentration when carboxylation rates by ribulose-bisphosphate carboxylase/oxygenase are lower than decarboxylation rates by malic enzyme. Differential accumulation of thylakoid proteases (Egy and DegP), state transition kinases (STN7,8), and Photosystem I and II assembly factors was observed, suggesting that cell-specific photosynthetic electron transport depends on post-translational regulatory mechanisms. BS/M ratios for inner envelope transporters phosphoenolpyruvate/P(i) translocator, Dit1, Dit2, and Mex1 were determined and reflect metabolic fluxes in carbon metabolism. A wide variety of hundreds of other proteins showed differential BS/M accumulation. Mass spectral information and functional annotations are

Energizing porters by proton-motive force.

Science.gov (United States)

Nelson, N

1994-11-01

It is generally accepted that the chemistry of water was the most crucial determinant in shaping life on earth. Among the more important chemical features of water is its dissociation into protons and hydroxyl ions. The presence of relatively high proton concentrations in the ambient solution resulted in the evolution of proton pumps during the dawn of life on earth. These proton pumps maintained neutral pH inside the cells and generated electrochemical gradients of protons (proton-motive force) across their membranes. The existence of proton-motive force enabled the evolution of porters driven by it that are most probably among the more primitive porters in the world. The directionality of the substrate transport by the porters could be to both sides of the membranes because they can serve as proton symporters or antiporters. One of the most important subjects of this meeting is the mechanism by which proton-motive and other ion-motive forces drive the transport processes through porters. Is there a common mechanism of action for all proton-driven porters? Is there some common partial reaction by which we can identify the way that porters are energized by proton-motive force? Is there a common coupling between proton movement and uptake or secretion of certain molecules? Even a partial answer to one of these questions would advance our knowledge... or confusion. As my mentor Efraim Racker used to say: 'If you are not totally confused you do not understand the issue'.

Por uma nova ordem energética global? potencialidades e perspectivas da questão energética entre os países BRICS

Directory of Open Access Journals (Sweden)

José María Gómez

2012-12-01

Full Text Available O presente artigo propõe analisar a questão energética entre os BRICS e o potencial de rearticulação da ordem energética global que dela emerge. Para tal, realiza três movimentos. Em primeiro lugar, investiga o crescente impacto agregado dos países BRICS no cenário energético global, com vistas a analisar seu avanço em uma temática até então reduto dos países desenvolvidos. Em segundo lugar, aborda a matriz energética de cada um dos cinco países do ponto de vista de suas economias políticas e da questão da sustentabilidade. Em terceiro lugar, e com base na seção anterior, propõe mapear as áreas de conflito e de possível aproximação entre os BRICS, na tentativa de localizar as possibilidades e limites da sua cooperação energética. Com base nessa investigação, conclui que, diante das potencialidades para a cooperação entre os países, a organização de suas ofertas e demandas energéticas nacionais pode permitir ao agrupamento articular-se como um novo polo no cenário energético global.

Aplicación electrónica para el ahorro de energía eléctrica utilizando una energía alternativa

Directory of Open Access Journals (Sweden)

Juan Carlos Cruz-Ardila

2013-01-01

Full Text Available El artículo presenta un trabajo orientado a disminuir el consumo de energía eléctrica entregada por la red eléctrica convencional, a través del aprovechamiento de la energía solar fotovoltaica. Se propone el diseño de un sistema de transferencia electrónica que facilita el uso de la energía eléctrica DC proveniente del panel solar, suprimiendo de esta manera, la utilización del inversor de voltaje, comúnmente usado en este tipo de aplicaciones y que eleva el costo de utilización de la energía solar. Se da a conocer inicialmente una revisión del estado del arte, que permite contextualizar el problema resuelto a partir de una energía renovable como la fotovoltaica, destacándose que actualmente España es el país con mayor desarrollo en este tema. Luego, se muestra el desarrollo secuencial del sistema de alimentación y la transferencia electrónica, haciendo una descripción de las variables identificadas y explicación, con el uso de diagramas de flujo, del sistema embebido implementado. También se da una descripción de los dispositivos usados tal como el sensor de corriente, la regulación y la rectificación. Se muestra el esquemático de la transferencia implementada. Finalmente, se revelan los resultados y las pruebas operacionales realizadas al sistema para demostrar la funcionalidad de la aplicación electrónica en el ahorro de la energía eléctrica utilizando una energía alternativa.

29 CFR 1926.957 - Construction in energized substations.

Science.gov (United States)

2010-07-01

... Distribution § 1926.957 Construction in energized substations. (a) Work near energized equipment facilities. (1... lines. When it is necessary to deenergize equipment or lines for protection of employees, the... large electrical equipment, transformers, or breakers. (f) Storage. The storage requirements of § 1926...

La pobreza energética y sus implicaciones

OpenAIRE

Mikel González-Eguino

2014-01-01

32 p. El sector energético se enfrenta en las próximas décadas a tres grandes transformaciones relacionadas con el cambio climático, la seguridad de suministro y la pobreza energética. Las dos primeras han sido analizadas ampliamente. Sin embargo, la pobreza energética ha pasado más desapercibida a pesar de tener una gran influencia en la vida de millones de personas, especialmente en los países más pobres. Actualmente, 1.300 millones de personas (el 20% de la población mundial) no tienen ...

Spectral studies of Lanthanide interactions with membrane surfaces

Energy Technology Data Exchange (ETDEWEB)

Karukstis, K.K.; Kao, M.Y.; Savin, D.A.; Bittker, R.A.; Kaphengst, K.J.; Emetarom, C.M.; Naito, N.R.; Takamoto, D.Y. [Harvey Mudd College, Claremont, CA (United States)

1995-03-23

We have monitored the interactions of the series of trivalent lanthanide cations with the thylakoid membrane surface of spinach chloroplasts using two complementary spectral techniques. Measurements of the fluorescence emission of the extrinsic probe 2-p-toluidinonaphthalene-6-sulfonate (TNS) and the absorbance of the intrinsic chromophore chlorophyll provide two sensitive means of characterizing the dependence of the cation-membrane interaction on the nature of the cation. In these systems, added lanthanide cations adsorb onto the membrane surface to neutralize exposed segments of membrane-embedded protein complexes. The lanthanide-induced charge neutralization increases the proximity of added TNS anion to the membrane surface as evidenced by variations in the TNS fluorescence level and wavelength of maximum emission. Our results reveal a strong dependence of TNS fluorescence parameters on both lanthanide size and total orbital angular momentum L value. Lanthanides with greater charge density (small size and/or low L value) enhance the TNS fluorescence level to a greater extent. A possible origin for the lanthanide-dependent TNS fluorescence levels is suggested in terms of a heterogeneity in the number and type of TNS binding sites. The data are consistent with the proposal that larger lanthanides with smaller enthalpies of hydration induce more significant membrane appression. 59 refs., 9 figs., 2 tabs.

Quality control of Photosystem II: reversible and irreversible protein aggregation decides the fate of Photosystem II under excessive illumination

Directory of Open Access Journals (Sweden)

Yasusi eYamamoto

2013-10-01

Full Text Available In response to excessive light, the thylakoid membranes of higher plant chloroplasts show dynamic changes including the degradation and reassembly of proteins, a change in the distribution of proteins, and large-scale structural changes such as unstacking of the grana. Here, we examined the aggregation of light-harvesting chlorophyll-protein complexes and Photosystem II core subunits of spinach thylakoid membranes under light stress with 77K chlorophyll fluorescence; aggregation of these proteins was found to proceed with increasing light intensity. Measurement of changes in the fluidity of thylakoid membranes with fluorescence polarization of diphenylhexatriene showed that membrane fluidity increased at a light intensity of 500–1,000 µmol photons m-2 s-1, and decreased at very high light intensity (1,500 µmol photons m-2 s-1. The aggregation of light-harvesting complexes at moderately high light intensity is known to be reversible, while that of Photosystem II core subunits at extremely high light intensity is irreversible. It is likely that the reversibility of protein aggregation is closely related to membrane fluidity: increases in fluidity should stimulate reversible protein aggregation, whereas irreversible protein aggregation might decrease membrane fluidity. When spinach leaves were pre-illuminated with moderately high light intensity, the qE component of non-photochemical quenching and the optimum quantum yield of Photosystem II increased, indicating that Photosystem II/ light-harvesting complexes rearranged in the thylakoid membranes to optimize Photosystem II activity. Transmission electron microscopy revealed that the thylakoids underwent partial unstacking under these light stress conditions. Thus, protein aggregation is involved in thylakoid dynamics and regulates photochemical reactions, thereby deciding the fate of Photosystem II.

Phenotype abnormality: 47 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available 47 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u1ria224u553i abnormal for trait of behavior...al quality in organ named thylakoid membrane during process named thylakoid membrane organization ... abnormal ... behavioral quality

Evaluación del potencial energético del oleaje en Madagascar

OpenAIRE

Araujo Roso, Giovanni

2017-01-01

La energía undimotriz, o energía del oleaje, es aquella que aprovecha la energía cinética de la perturbación de la superficie del mar y está considerada como una fuente de gran potencial. Las ventajas de este tipo de recurso respecto a otras energías renovables son variadas: sus eventos son predecibles con detalle, el despliegue de dispositivos tiene un impacto visual inferior a otros y es un recurso inagotable, entre otros. Por otra parte, el campo de la energía del oleaje se ...

Ponte en onda: prende la energía limpia, (Spanish) Get Current

Energy Technology Data Exchange (ETDEWEB)

None

2015-05-01

Cambiar a tecnologías de energía limpia significa que fortalecemos la economía y protegemos al medio ambiente. Este libreto de actividades educativas para todas las edades promueve el uso consciente de la energía, con datos de distintas formas de energía aplicables y una variedad de rompecabezas y crucigramas en temas energéticos.

La energía que requiere nuestro territorio

OpenAIRE

Pacheco, Máximo

2015-01-01

En esta columna de opinión, el Ministro de Energía nos invita a enfrentarnos a un problema crucial para un país como Chile: sin energía a precios razonables, esa desigualdad social que tanto criticamos terminará por expandirse. Pero a la vez el Ministro nos invita a cambiar el foco, y así «transformar la energía en un ecualizador de la igualdad», con un Estado más activo en la solución de esta crucial problemática. In this op-ed piece, the Minister of Energy invites us to face a crucial pr...

La energía humana el esfuerzo físico

Directory of Open Access Journals (Sweden)

Luis Suárez Flórez

1991-01-01

Full Text Available Se llama la atención sobre la energía humana, su importancia como elemento de productividad y como principio ó quizás como fin de la actividad deportiva. Se estudia el máximo esfuerzo físico, así como también algunos conceptos acerca de la energía aeróbica y la energía anaeróbica.

La energía minihidráulica en los planes de fomento de las energías renovables en España

OpenAIRE

Espejo Marín, Cayetano; García Marín, Ramón; Aparicio Guerrero, Ana Eulalia

2016-01-01

La energía minihidráulica incluye las centrales con una potencia instalada de hasta 10 megavatios. Esta tecnología de producción energética se ha incluido en los Planes de Fomento de las Energías Renovables promovidos por los Gobiernos de España desde finales de los años noventa a la actualidad. En esta aportación se analizan los objetivos de potencia a instalar en cada Comunidad Autónoma durante el periodo de vigencia de cada Plan, las barreras con las que se encuentra el sector para el desa...

Changes in photosynthesis and activities of enzymes involved in ...

African Journals Online (AJOL)

AJL

2012-04-26

Apr 26, 2012 ... oxygen and carbohydrates. In photosynthesis, a series of redox reactions occur in the electron transport system present in the chloroplast thylakoid membranes. Oxi- dation of water is catalyzed by photosystem II (PSII), a multi-subunit pigment protein complex located in the thylakoid membrane (Hillier and ...

La educación energética una prioridad para el milenio

Directory of Open Access Journals (Sweden)

Johnn Edgar Castro

2015-01-01

Full Text Available Este articulo plantea la necesidad  de reflexionar y trabajar en el desarrollo de propuestas sobre educación energética, desde cuatro enfoques fundamentalmente: la primera de ellas  es la inevitable dependencia de las sociedades humanas de las fuentes de energía; el ahorro energético; el agotamiento de las fuentes de energía y por ultimo las consecuencias sobre el medioambiente

Proteomics of the chloroplast: systematic identification and targeting analysis of lumenal and peripheral thylakoid proteins

DEFF Research Database (Denmark)

Peltier, J B; Friso, G; Kalume, D E

2000-01-01

The soluble and peripheral proteins in the thylakoids of pea were systematically analyzed by using two-dimensional electrophoresis, mass spectrometry, and N-terminal Edman sequencing, followed by database searching. After correcting to eliminate possible isoforms and post-translational modificati......The soluble and peripheral proteins in the thylakoids of pea were systematically analyzed by using two-dimensional electrophoresis, mass spectrometry, and N-terminal Edman sequencing, followed by database searching. After correcting to eliminate possible isoforms and post......-translational modifications, we estimated that there are at least 200 to 230 different lumenal and peripheral proteins. Sixty-one proteins were identified; for 33 of these proteins, a clear function or functional domain could be identified, whereas for 10 proteins, no function could be assigned. For 18 proteins, no expressed...... sequence tag or full-length gene could be identified in the databases, despite experimental determination of a significant amount of amino acid sequence. Nine previously unidentified proteins with lumenal transit peptides are presented along with their full-length genes; seven of these proteins possess...

30 CFR 77.704-2 - Repairs to energized high-voltage lines.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized high-voltage lines. 77.704... UNDERGROUND COAL MINES Grounding § 77.704-2 Repairs to energized high-voltage lines. An energized high-voltage... repairs will be performed on power circuits with a phase-to-phase nominal voltage no greater than 15,000...

Ahorre Energía: Consejos para ahorro dinero y energía en su hogar (Spanish Brochure), Energy Saver Guide

Energy Technology Data Exchange (ETDEWEB)

None

2017-11-01

La versión en castellano de la guía del Departamento de Energía de los Estados Unidos que ayuda a consumidores a ahorrar energía y dinero en su hogar y en las carreteras. The Spanish-language version of U.S. Department of Energy's Energy Saver consumer guide to saving energy and money at home and on the road.

Activity, polypeptide and gene identification of thylakoid Ndh complex in trees: potential physiological relevance of fluorescence assays.

Science.gov (United States)

Serrot, Patricia H; Sabater, Bartolomé; Martín, Mercedes

2012-09-01

Three evergreen (Laurus nobilis, Viburnum tinus and Thuja plicata) and two autumnal abscission deciduous trees (Cydonia oblonga and Prunus domestica) have been investigated for the presence (zymogram and immunodetection) and functionality (post-illumination chlorophyll fluorescence) of the thylakoid Ndh complex. The presence of encoding ndh genes has also been investigated in T. plicata. Western assays allowed tentative identification of zymogram NADH dehydrogenase bands corresponding to the Ndh complex after native electrophoresis of solubilized fractions from L. nobilis, V. tinus, C. oblonga and P. domestica leaves, but not in those of T. plicata. However, Ndh subunits were detected after SDS-PAGE of thylakoid solubilized proteins of T. plicata. The leaves of the five plants showed the post-illumination chlorophyll fluorescence increase dependent on the presence of active Ndh complex. The fluorescence increase was higher in autumn in deciduous, but not in evergreen trees, which suggests that the thylakoid Ndh complex could be involved in autumnal leaf senescence. Two ndhB genes were sequenced from T. plicata that differ at the 350 bp 3' end sequence. Comparison with the mRNA revealed that ndhB genes have a 707-bp type II intron between exons 1 (723 bp) and 2 (729 bp) and that the UCA 259th codon is edited to UUA in mRNA. Phylogenetically, the ndhB genes of T. plicata group close to those of Metasequoia, Cryptomeria, Taxodium, Juniperus and Widdringtonia in the cupresaceae branch and are 5' end shortened by 18 codons with respect to that of angiosperms. Copyright © Physiologia Plantarum 2012.

Energía Minihidráulica

OpenAIRE

Mancebo Piqueras, José Antonio; Adrada Guerra, Teodoro; Martinez, Carmen

2013-01-01

La energía basada en turbinas hidráulicas de reducida potencia es, a menudo, un ejemplo- modelo dentro del campo de las energías renovables desde su aparición a finales del S. XIX, aunque los ingenios precursores surgen mucho antes. Entre los testimonios más antiguos destacan la saqia o rueda persa y la rueda hidráulica romana que había sido previamente implementada en Extremo Oriente, y que después llega a Europa a través de Egipto. Más tarde, durante la Edad Media y el Renacimiento, se gene...

Som Energia: sostenibilitat energètica i cooperativisme

OpenAIRE

Duran i Grant, Alexandre; Huijink, Gijsbert; Roselló, Marc

2013-01-01

La cooperativa Som Energia és una organització innovadora en el sector energètic a casa nostra. Proposa una forma de fer diferent de la de les empreses tradicionals del sector: ven energia renovable certificada, no té ànim de lucre i busca el bé comú. La proposta treballa per la sostenibilitat energètica.

Sistema de Aprovechamiento de la Energía de las Olas del Mar

OpenAIRE

Pi Amorós, Gabriel

2010-01-01

Este documento describe un sistema de aprovechamiento de la energía transportada por el oleaje o energía undimotriz. El sistema no transformará la energía únicamente en electricidad si no que aprovecha dicha electricidad para producir hidrógeno mediante el proceso de la electrólisis del agua de mar. Es decir, el sistema propuesto es un sistema de generación de hidrógeno de origen renovable a partir de una fuente de energía renovable, la energía undimotriz. Las característica...

Medidas de mejora de la eficiencia energética de edificios residenciales

OpenAIRE

Hernández Sánchez, Juan Manuel

2012-01-01

El parque de edificios residenciales existente tiene un potencial muy grande para mejorar la eficiencia energética a corto y medio plazo, debido al gran número de viviendas existentes y a su larga vida residual. Los factores que influyen directamente en el consumo energético y en las emisiones asociadas a los edificios residenciales son: la envolvente térmica, la eficiencia energética de los equipos, las fuentes energéticas utilizadas y el comportamiento de los usuarios. Las barreras qu...

Distinguishing the Roles of Thylakoid Respiratory Terminal Oxidases in the Cyanobacterium Synechocystis sp. PCC 6803.

Science.gov (United States)

Ermakova, Maria; Huokko, Tuomas; Richaud, Pierre; Bersanini, Luca; Howe, Christopher J; Lea-Smith, David J; Peltier, Gilles; Allahverdiyeva, Yagut

2016-06-01

Various oxygen-utilizing electron sinks, including the soluble flavodiiron proteins (Flv1/3), and the membrane-localized respiratory terminal oxidases (RTOs), cytochrome c oxidase (Cox) and cytochrome bd quinol oxidase (Cyd), are present in the photosynthetic electron transfer chain of Synechocystis sp. PCC 6803. However, the role of individual RTOs and their relative importance compared with other electron sinks are poorly understood, particularly under light. Via membrane inlet mass spectrometry gas exchange, chlorophyll a fluorescence, P700 analysis, and inhibitor treatment of the wild type and various mutants deficient in RTOs, Flv1/3, and photosystem I, we investigated the contribution of these complexes to the alleviation of excess electrons in the photosynthetic chain. To our knowledge, for the first time, we demonstrated the activity of Cyd in oxygen uptake under light, although it was detected only upon inhibition of electron transfer at the cytochrome b6f site and in ∆flv1/3 under fluctuating light conditions, where linear electron transfer was drastically inhibited due to impaired photosystem I activity. Cox is mostly responsible for dark respiration and competes with P700 for electrons under high light. Only the ∆cox/cyd double mutant, but not single mutants, demonstrated a highly reduced plastoquinone pool in darkness and impaired gross oxygen evolution under light, indicating that thylakoid-based RTOs are able to compensate partially for each other. Thus, both electron sinks contribute to the alleviation of excess electrons under illumination: RTOs continue to function under light, operating on slower time ranges and on a limited scale, whereas Flv1/3 responds rapidly as a light-induced component and has greater capacity. © 2016 American Society of Plant Biologists. All Rights Reserved.

El hidrógeno y la energía

OpenAIRE

Aurelio Mendoza Medellín

2006-01-01

El hidrógeno es el elemento más simple, pero es fundamental para la vida. En el futuro sustituirá a los combustibles fósiles como fuente de energía para las máquinas hechas por el hombre. Hoy en día su uso es muy caro, pero ya existen motores que trabajan quemando este gas. En el sol la fusión de hidrógeno libera cantidades inconmensurables de energía, que en parte es captada por los cloroplastos, que la transforman en la energía química contenida en los carbohidratos resultantes de la fotosí...

El hidrógeno y la energía

OpenAIRE

Aurelio Mendoza Medellín

2006-01-01

El hidrógeno es el elemento más simple, pero es fundamental para la vida. En el futuro sustituirá a los combustibles fósiles como fuente de energía para las máquinas hechas por el hombre. Hoy en día su uso es muy caro, pero ya existen motores que trabajan quemando este gas. En el sol la fusión de hidrógeno libera cantidades inconmensurables de energía, que en parte es captada por los cloroplastos, que la transforman en la energía química contenida en los carbohidratos resultantes ...

Final Technical Report, reEnergize Program

Energy Technology Data Exchange (ETDEWEB)

Wamstad-Evans, Kristi [City of Omaha; Williams, Eric [City of Omaha; Kubicek, Jason [City of Omaha

2013-12-27

The reEnergize Program helped to build a market for residential and commercial energy evaluations and upgrades. The program provided incentives to encourage participants to save energy, save money, and make their homes and businesses more safe, healthy, and comfortable. As part of the Better Buildings Neighborhood Program (BBNP), the successful investment of this $10 million grant toward market development was the first grant funding collaboration between the cities of Omaha and Lincoln. Through more than three years of work, thousands of participants, contractors, and community members worked together to make the reEnergize Program a demonstration of how to “Build Energy Smart Communities.”

Testable, fault-tolerant power interface circuit for normally de-energized loads

International Nuclear Information System (INIS)

Hager, R.E.

1987-01-01

A power interface circuit is described for supplying power from a power line to a normally de-energized process control apparatus in a pressurized light water nuclear power system in dependence upon three input signals, comprising: voter means for supplying power to the normally de-energized load when at least two of the three input signals indicate that the normally de-energized load should be activated; a normally closed switch, operatively connected to the power line and the voter means, for supplying power to the voter means during ordinary operation; a first resistor operatively connected to the power line; a current detector operatively connected to the first resistor and the voter means; a second resistor operatively connected to the current detector and ground; and current sensor means, operatively connected between the voter means and the normally de-energized load, for detecting the power supplied to the normally de-energized load by the voter means

30 CFR 75.705-2 - Repairs to energized surface high-voltage lines.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized surface high-voltage lines... Repairs to energized surface high-voltage lines. An energized high-voltage surface line may be repaired... on power circuits with a phase-to-phase nominal voltage no greater than 15,000 volts; (3) Such...

Situación actual del sector energético en España

Directory of Open Access Journals (Sweden)

Carlos J. Pardo Abad

2001-01-01

Full Text Available La energía es un sector clave de la economía española y está presente en todos los procesos productivos. El artículo analiza al sector en los últimos años con datos procedentes de varios organismos públicos, referidos tanto al balance energético general como a los sectores energéticos, las energías renovables, la política energética y las relaciones entre energía y medio ambiente. Características básicas del sector en nuestro país son el incremento del consumo de energía, la progresiva liberalización y las grandes inversiones en energías renovables, sobre todo la eólica. Energy is a key sector of the Spanish economy and it is in all productivo processes.This article analyses the sector in the last fewyears with data from some public agencies, referred to the power balance as well as to nuclear power, coal, oil, natural gas, renewable energies, power policy and the relationship between energy and environment. The main eatures of energy in Spain are the increase of consumption, the growing liberation and the big investments in renewable energies, above all the eolic one.

Producción, Reservas y Sostenibilidad de la Energía en Venezuela

Directory of Open Access Journals (Sweden)

Juan Carlos Rojas-Zerpa

2015-06-01

Full Text Available El propósito del presente trabajo está relacionado con la evaluación de los recursos energéticos de Venezuela y su posicionamiento estratégico mundial, referido principalmente a la producción y consumo de energía primaria y reservas. Así mismo se han evaluado los recursos energéticos renovables con la finalidad de identificar oportunidades para el desarrollo de la energía sostenible. Los resultados indican que Venezuela posee recursos fósiles para más de 130 años de explotación, lo cual lo convierte en una potencia energética relevante en el contexto mundial. La potencialidad aprovechable de las energías renovables duplicó la producción de recursos fósiles en 2011. En la actualidad, el aprovechamiento de estas fuentes es inferior al 2 % del total disponible, lo que deja abierto un amplio rango de posibilidades para la diversificación de la matriz energética nacional mediante tecnologías limpias o sostenibles

Cálculo del balance de energía para higuerilla (Ricinus communis L. desde las etapas de producción en campo hasta el valor energético de cada componente de la planta

Directory of Open Access Journals (Sweden)

Hipólito Ortíz-Laurel

2017-01-01

Full Text Available Introducción : Pruebas de balance de energía permiten redirigir los insumos desde las etapas de producción de un cultivo, e igualmente, precesar la cantidad de energía utilizada para cada proceso y así, verificar la eficiencia al transformar la energía contenida en el cultivo cuando debe cumplir con una función deseada. Método : la planta de higuerilla (Ricinus communis L. con propósitos de cultivo energético fue sembrada en campo y sometida a procesos de mantenimiento de l cultivo y en la cosecha, la planta completa fue colectada para análisis energético, donde cada una de sus partes inclu i das las semillas fueron evaluadas en función de su contenido de energía. Así, para determinar el balance de energía; los valores de la energía biológica de la planta fueron comparados con la energía aplicada en cada uno de los procesos técnicos y físicos para la producción del cult i vo y en su procesamiento . Resultados : La energía aplicada para producir el cultivo r esulta un 28% superior a la energía a obtener de la planta. Asimismo, la biomasa de la planta completa de higuerilla, sin contar las semillas genera el doble de energía comparado con el aceite de las semillas, por lo que, conviene utilizar toda la planta e n términos de energía . Conclusión : Es recomendable utilizar el aceite de las seillas como biomaterial, ya que el b a lance es positivo en un 15%.

Panorama energético mundial y argentino

OpenAIRE

Guadagni, Alieto

2007-01-01

Estamos transitando aceleradamente de una etapa caracterizada por energía abundante, barata y exportada a otra etapa signada por la escasez, el alto costo y las importaciones. Esta es la triple tenaza energética que enfrenta la Argentina. Los actuales precios del petróleo están impulsando la producción de biocombustibles (biodiesel y etanol) en Brasil, la Unión Europea y los Estados Unidos, pero también muchos otros países como el nuestro. Se estima que su participación en el consumo mundi...

El hidrógeno y la energía

Directory of Open Access Journals (Sweden)

Aurelio Mendoza Medellín

2006-01-01

Full Text Available El hidrógeno es el elemento más simple, pero es fundamental para la vida. En el futuro sustituirá a los combustibles fósiles como fuente de energía para las máquinas hechas por el hombre. Hoy en día su uso es muy caro, pero ya existen motores que trabajan quemando este gas. En el sol la fusión de hidrógeno libera cantidades inconmensurables de energía, que en parte es captada por los cloroplastos, que la transforman en la energía química contenida en los carbohidratos resultantes de la fotosíntesis. Esto implica la transferencia del hidrógeno del agua al dióxido de carbono. Los animales liberan la energía de los combustibles biológicos revirtiendo dicha reacción a través del metabolismo oxidativo, la cadena respiratoria y la fosforilación oxidativa. El hidrógeno es vital para producir ATP y por lo tanto para la vida.

Control Operator for the Two-Dimensional Energized Wave Equation

Directory of Open Access Journals (Sweden)

Sunday Augustus REJU

2006-07-01

Full Text Available This paper studies the analytical model for the construction of the two-dimensional Energized wave equation. The control operator is given in term of space and time t independent variables. The integral quadratic objective cost functional is subject to the constraint of two-dimensional Energized diffusion, Heat and a source. The operator that shall be obtained extends the Conjugate Gradient method (ECGM as developed by Hestenes et al (1952, [1]. The new operator enables the computation of the penalty cost, optimal controls and state trajectories of the two-dimensional energized wave equation when apply to the Conjugate Gradient methods in (Waziri & Reju, LEJPT & LJS, Issues 9, 2006, [2-4] to appear in this series.

La Demanda Residencial por Energía Eléctrica en Chile

OpenAIRE

Claudio A Agostini; Cecilia Plottier; Eduardo Saavedra

2011-01-01

En un contexto de demanda creciente y oferta estocástica de energía en Chile se hace necesario conocer a cabalidad los determinantes de la demanda por energía eléctrica de los hogares - en particular su elasticidad precio - para así utilizar mecanismos de flexibilización de precios con miras a reducir posibles déficits de energía. Este trabajo estima la demanda de energía eléctrica residencial usando información de la Encuesta de Caracterización Socioeconómica Nacional (CASEN) 2006, siendo in...

In vitro degradation of the 32kDa PS II reaction centre protein

International Nuclear Information System (INIS)

Eckenswiller, L.C.; Greenberg, B.M.

1989-01-01

The 32kDa thylakoid membrane protein is an integral component of the PS II reaction centre. The protein, although stable in the dark, undergoes light dependent turnover. Light from the UV, visible and far-red spectral regions induce 32kDa protein degradation. To better understand 32kDa protein metabolism, an in vitro degradation system is being developed. It consists of isolated thylakoid membranes than contain radiolabelled protein. The 32kDa protein is actively and specifically degraded when the thylakoid preparation is exposed to UV or visible radiation. The protein is stable in the dark. The herbicides (atrazine and DCMU) inhibit degradation in the in vitro system as they do in vivo. Additionally, several methods of isolating thylakoids are being compared to optimize the 32kDa protein degradation reaction. The preparations will be evaluated based on their ability to permit light dependent degradation of the 32kDa protein without affecting the other membrane components

Trienoic fatty acids and plant tolerance of temperature

Directory of Open Access Journals (Sweden)

Routaboul Jean-Marc

2002-01-01

Full Text Available The biophysical reactions of light harvesting and electron transport during photosynthesis take place in a uniquely constructed bilayer, the thylakoid. In all photosynthetic eukaryotes, the complement of atypical glycerolipid molecules that form the foundation of this membrane are characterised by sugar head-groups and a very high level of unsaturation in the fatty acids that occupy the central portion of the thylakoid bilayer. alpha-linolenic (18:3 or a combination of 18:3 and hexadecatrienoic (16:3 acids typically account for approximately two-thirds of all thylakoid membrane fatty acids and over 90% of the fatty acids of monogalactosyl diacylglycerol, the major thylakoid lipid [1, 2]. The occurrence of trienoic fatty acids as a major component of the thylakoid membrane is especially remarkable since these fatty acids form highly reactive targets for active oxygen species and free radicals, which are often the by-products of oxygenic photosynthesis. Photosynthesis is one of the most temperature-sensitive functions of plant [3, 4]. There remains a widespread belief that these trienoic fatty acids might have some crucial role in plants to be of such universal occurrence, especially in photosynthesis tolerance of temperature [5].

Ahorre Energía: Consejos sobre el ahorro de dinero y energía en el hogar (Spanish Brochure), Energy Savers Guide

Energy Technology Data Exchange (ETDEWEB)

None

2014-09-01

La versión en castellano de la guía del Departamento de Energía de los Estados Unidos que ayuda a consumidores a ahorrar energía y dinero en el hogar y en las carreteras. The Spanish-language version of U.S. Department of Energy's consumer guide to saving energy and money at home and on the road.

Energization of Long HVAC Cables in Parallel - Analysis and Estimation Formulas

DEFF Research Database (Denmark)

Silva, Filipe Faria Da; Bak, Claus Leth

2012-01-01

The installation of long HVAC cables has recently become more common and it tends to increase during the next years. Consequently, the energization of long HVAC cables in parallel is also a more common condition. The energization of HVAC cables in parallel resembles the en-ergization of capacitor...... has several simplifications and does not always provide accurate results. This paper proposes a new formula that can be used for the estimation of these two quantities for two HVAC cables in parallel....

Estudio de viabilidad de un sistema de generación de energía eléctrica basado en energías renovables para países en vías de desarrollo

OpenAIRE

Villanueva Fernández, Gemma

2010-01-01

En este proyecto, primero se realiza una pequeña introducción para que el lector adquiera unos conocimientos mínimos sobre las energías renovables. Posteriormente, se describe los conceptos básicos de la energía solar fotovoltaica y los materiales usados en la misma. La energía solar fotovoltaica, es una transformación de la energía luminosa en energía eléctrica. El material más utilizado en la fabricación de los paneles solares es el silicio. De igual forma, se describe conceptos básicos de ...

Obtención de energía a partir de las corrientes marinas

OpenAIRE

Echeverría Cabodevilla, Álvaro

2017-01-01

El objetivo del proyecto es evaluar la viabilidad de una granja de energía hidrocinética en los territorios marinos españoles. Como se puede observar en el desarrollo del estudio, el resultado es negativo. En España no existe una gran zona que pueda ser utilizada para crear una granja de energía hidrocinética. La energía hidrocinética es aquella que utiliza la energía cinética del agua marina para obtener electricidad, principalmente los movimientos de agua de las corrientes ma...

Energizing Subject Guide Service with Web 2.0

Directory of Open Access Journals (Sweden)

Sheau-Hwang Chang

2014-06-01

Full Text Available This article will use LibGuides as an example to illustrate how a Web 2.0 platform can energize the subject guide service and give librarians an edge in expanding their roles. Topics to be discussed will include a brief introduction to LibGuides and its capabilities to energize subject guide creation, how it has been used by academic libraries, how it is used in Maxwell Library in expanding librarian's role, and finally its implications on librarianship.

Estudio del balance energético en velocistas de alto rendimiento

OpenAIRE

Lorente Gutiérrez, Jesús

2015-01-01

El objetivo de este estudio fue evaluar el balance energético en tres atletas de alto rendimiento durante 28 días, que coincidieron con el periodo competitivo de pista cubierta. La ingesta energética fue estudiada a partir de registros alimentarios durante los 28 días. Del mismo modo, el gasto energético fue estimado por tres métodos, mediante registros de actividad durante 28 días, mediante el estudio del ritmo metabólico basal estudiado por calorimetría indirecta, aplicándole el fa...

Modelado Energético de Convertidores Primarios para el Aprovechamiento de las Energías Renovables Marinas

Directory of Open Access Journals (Sweden)

Amable López

2014-04-01

Full Text Available Resumen: El objetivo principal de este artículo es presentar los métodos más habituales de aprovechamiento de distintos tipos de energías renovables procedentes del mar y analizar los modelos energéticos de los dispositivos utilizados para su explotación. Estos modelos son necesarios para el diseño del dispositivo así como para el estudio de su comportamiento dinámico. Su conocimiento resulta imprescindible también para su simulación dinámica y para el diseño de los algoritmos de control necesarios para conseguir una optimización energética y económica. En este trabajo se presentan algunos de los diferentes tipos de energías del mar, y se j ustifica el interés en el desarrollo de dispositivos específicos para el aprovechamiento de las corrientes marinas y de las olas, junto con una pequeña clasificación en función de la profundidad del agua en la zona de instalación de estos dispositivos. Para los convertidores de energía de las olas, generalmente, de tipo resonante, se presenta una metodología de tipo general, analizando los distintos campos de fuerzas actuantes y los métodos de obtención de las respuestas temporal y frecuencial. Para los dispositivos de aprovechamiento de las corrientes, se propone una metodología simplificada de modelado dinámico que puede ser utilizada en análisis del dispositivo concreto. Para ello se tiene en cuenta los perfiles hidrodinámicos que utilizan estos dispositivos, los datos del perfil de la corriente con la profundidad y del modelo de oleaje, y la dinámica propia del conjunto multiplicadora y generador eléctrico. La metodología propuesta se aplica al estudio de un caso concreto, correspondiente a un rotor de eje horizontal de un convertidor de energía de las corrientes. Los resultados obtenidos permiten analizar los efectos del oleaje y de las condiciones de flujo de la corriente no uniforme sobre las magnitudes energéticas más importantes. Abstract: The main objective of

Anchoring a plant cytochrome P450 via PsaM to the thylakoids in Synechococcus sp. PCC 7002: evidence for light-driven biosynthesis.

Directory of Open Access Journals (Sweden)

Lærke Münter Lassen

Full Text Available Plants produce an immense variety of specialized metabolites, many of which are of high value as their bioactive properties make them useful as for instance pharmaceuticals. The compounds are often produced at low levels in the plant, and due to their complex structures, chemical synthesis may not be feasible. Here, we take advantage of the reducing equivalents generated in photosynthesis in developing an approach for producing plant bioactive natural compounds in a photosynthetic microorganism by functionally coupling a biosynthetic enzyme to photosystem I. This enables driving of the enzymatic reactions with electrons extracted from the photosynthetic electron transport chain. As a proof of concept, we have genetically fused the soluble catalytic domain of the cytochrome P450 CYP79A1, originating from the endoplasmic reticulum membranes of Sorghum bicolor, to a photosystem I subunit in the cyanobacterium Synechococcus sp. PCC 7002, thereby targeting it to the thylakoids. The engineered enzyme showed light-driven activity both in vivo and in vitro, demonstrating the possibility to achieve light-driven biosynthesis of high-value plant specialized metabolites in cyanobacteria.

Structural adaptations of proteins to different biological membranes

Science.gov (United States)

Pogozheva, Irina D.; Tristram-Nagle, Stephanie; Mosberg, Henry I.; Lomize, Andrei L.

2013-01-01

To gain insight into adaptations of proteins to their membranes, intrinsic hydrophobic thicknesses, distributions of different chemical groups and profiles of hydrogen-bonding capacities (α and β) and the dipolarity/polarizability parameter (π*) were calculated for lipid-facing surfaces of 460 integral α-helical, β-barrel and peripheral proteins from eight types of biomembranes. For comparison, polarity profiles were also calculated for ten artificial lipid bilayers that have been previously studied by neutron and X-ray scattering. Estimated hydrophobic thicknesses are 30-31 Å for proteins from endoplasmic reticulum, thylakoid, and various bacterial plasma membranes, but differ for proteins from outer bacterial, inner mitochondrial and eukaryotic plasma membranes (23.9, 28.6 and 33.5 Å, respectively). Protein and lipid polarity parameters abruptly change in the lipid carbonyl zone that matches the calculated hydrophobic boundaries. Maxima of positively charged protein groups correspond to the location of lipid phosphates at 20-22 Å distances from the membrane center. Locations of Tyr atoms coincide with hydrophobic boundaries, while distributions maxima of Trp rings are shifted by 3-4 Å toward the membrane center. Distributions of Trp atoms indicate the presence of two 5-8 Å-wide midpolar regions with intermediate π* values within the hydrocarbon core, whose size and symmetry depend on the lipid composition of membrane leaflets. Midpolar regions are especially asymmetric in outer bacterial membranes and cell membranes of mesophilic but not hyperthermophilic archaebacteria, indicating the larger width of the central nonpolar region in the later case. In artificial lipid bilayers, midpolar regions are observed up to the level of acyl chain double bonds. PMID:23811361

Balance de energía en cultivos hortícolas a campo en Rosario (Santa Fe, Argentina

Directory of Open Access Journals (Sweden)

J. Denoia

2010-01-01

Full Text Available Se analizó la gestión de la energía en cultivos de papa, tomate y lechuga en un área próxima a la ciudad de Rosario (Argentina. Se consideraron todos los ingresos de materia al sistema y su producción transformándolos en energía al multiplicar las cantidades de insumos por sus contenidos energéticos. Se analizó tanto la energía directa como la indirecta. Se estudió la gestión energética dentro de los límites físicos del sistema. Los indicadores empleados fueron: eficiencia energética (EfE y productividad energética (PE. Los balances energéticos de papa y tomate fueron negativos, mientras que en lechuga, la energía producida fue menor que la ingresada. La mayor eficiencia energética se registró en tomate (3,54, seguida por papa (2,69; la menor fue en lechuga (0,25. La energía ingresada en tomate resultó la más eficiente (88,6 kgMS/100 Mj, seguida por la de papa (16 kgMS/100 Mj y la de lechuga (10,8 kgMS/100 Mj.

La inversión en energías renovables en Argentina

OpenAIRE

Recalde, Marina

2017-01-01

En este artículo se analiza en qué medida los factores del entorno de la política energética de un país en desarrollo, tal como Argentina, determinan la evolución de la inversión en energías renovables. La baja calidad institucional del país ayuda a crear condiciones no propicias que contrarrestan el efecto de la política energética, reduciendo los incentivos para invertir en tecnologías renovables. Es necesario entonces mejorar las condiciones institucionales de los países en desarrollo para...

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine inhibits proton motive force in energized liver mitochondria

International Nuclear Information System (INIS)

Singh, Y.; Bhatnagar, R.; Sidhu, G.S.; Batra, J.K.; Krishna, G.

1989-01-01

It is known that 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which induces Parkinson's-like disease in primates and humans, depletes hepatocytes of ATP and subsequently causes cell death. Incubation of rat liver mitochondria with MPTP and 1-methyl-4-phenyl pyridinium ion (MPP+) significantly inhibited incorporation of 32 Pi into ATP. MPTP and MPP+ inhibited the development of membrane potential and pH gradient in energized rat liver mitochondria, suggesting that reduction of the proton motive force may have reduced ATP synthesis. Since deprenyl, an inhibitor of monoamine oxidase, prevented the formation of MPP+ and inhibited the decrease in membrane potential caused by MPTP, but not that caused by MPP+, these effects of MPTP, as well as cell death, probably were mediated by MPP+. This mechanism may play a role in the specific loss of dopaminergic neurons resulting in MPTP-induced Parkinson's disease

Auditoría energética en una planta de tratamiento de agua potable

OpenAIRE

Díaz Álvarez, Silvino

2012-01-01

En el panorama energético actual, con las recientes incertidumbres asociadas a los precios de la energía y las inestabilidades políticas en algunos países exportadores de hidrocarburos, reducir el consumo energético mediante tecnologías más eficientes es fundamental en la definición de nuevos usos de la energía en nuestra sociedad. Dada la actual coyuntura medioambiental, económica y social, hemos de encontrar un nuevo modelo de desarrollo sostenible, incrementando la productividad de nuestra...

Assessing potential impacts of energized submarine power cables on crab harvests

Science.gov (United States)

Love, Milton S.; Nishimoto, Mary M.; Clark, Scott; McCrea, Merit; Bull, Ann Scarborough

2017-12-01

Offshore renewable energy facilities transmit electricity to shore through submarine power cables. Electromagnetic field emissions (EMFs) are generated from the transmission of electricity through these cables, such as the AC inter-array (between unit) and AC export (to shore) cables often used in offshore energy production. The EMF has both an electric component and a magnetic component. While sheathing can block the direct electric field, the magnetic field is not blocked. A concern raised by fishermen on the Pacific Coast of North America is that commercially important Dungeness crab (Metacarcinus magister Dana, 1852)) might not cross over an energized submarine power cable to enter a baited crab trap, thus potentially reducing their catch. The presence of operating energized cables off southern California and in Puget Sound (cables that are comparable to those within the arrays of existing offshore wind energy devices) allowed us to conduct experiments on how energized power cables might affect the harvesting of both M. magister and another commercially important crab species, Cancer productus Randall, 1839. In this study we tested the questions: 1) Is the catchability of crabs reduced if these animals must traverse an energized power cable to enter a trap and 2) if crabs preferentially do not cross an energized cable, is it the cable structure or the EMF emitted from that cable that deters crabs from crossing? In field experiments off southern California and in Puget Sound, crabs were given a choice of walking over an energized power cable to a baited trap or walking directly away from that cable to a second baited trap. Based on our research we found no evidence that the EMF emitted by energized submarine power cables influenced the catchability of these two species of commercially important crabs. In addition, there was no difference in the crabs' responses to lightly buried versus unburied cables. We did observe that, regardless of the position of the cable

Spatially Localized Particle Energization by Landau Damping in Current Sheets

Science.gov (United States)

Howes, G. G.; Klein, K. G.; McCubbin, A. J.

2017-12-01

Understanding the mechanisms of particle energization through the removal of energy from turbulent fluctuations in heliospheric plasmas is a grand challenge problem in heliophysics. Under the weakly collisional conditions typical of heliospheric plasma, kinetic mechanisms must be responsible for this energization, but the nature of those mechanisms remains elusive. In recent years, the spatial localization of plasma heating near current sheets in the solar wind and numerical simulations has gained much attention. Here we show, using the innovative and new field-particle correlation technique, that the spatially localized particle energization occurring in a nonlinear gyrokinetic simulation has the velocity space signature of Landau damping, suggesting that this well-known collisionless damping mechanism indeed actively leads to spatially localized heating in the vicinity of current sheets.

Membrane transport mechanism 3D structure and beyond

CERN Document Server

Ziegler, Christine

2014-01-01

This book provides a molecular view of membrane transport by means of numerous biochemical and biophysical techniques. The rapidly growing number of atomic structures of transporters in different conformations and the constant progress in bioinformatics have recently added deeper insights.   The unifying mechanism of energized solute transport across membranes is assumed to consist of the conformational cycling of a carrier protein to provide access to substrate binding sites from either side of a cellular membrane. Due to the central role of active membrane transport there is considerable interest in deciphering the principles of one of the most fundamental processes in nature: the alternating access mechanism.   This book brings together particularly significant structure-function studies on a variety of carrier systems from different transporter families: Glutamate symporters, LeuT-like fold transporters, MFS transporters and SMR (RND) exporters, as well as ABC-type importers.   The selected examples im...

Role conflict: cause of burnout or energizer?

Science.gov (United States)

Jones, M L

1993-03-01

A year-long study of public child welfare administrators examined the effects of role conflict on their attitudes and performance. Popular belief and some of the literature have suggested that burnout is inevitable for those confronted with role conflict. Other literature has proposed that it may instead be energizing to individuals and lead to greater personal and organizational effectiveness. This qualitative study found that individuals in the study had developed specific, effective skills for responding to role conflict. Although there was a public presentation of self that indicated they were under stress and in "impossible" situations, there was in fact an energizing effect resulting from the ongoing challenge of dealing with conflict.

Nexo agua-energía: desde el nacimiento del río Llobregat hasta Manresa

OpenAIRE

Prieto Márquez, Kelly; Badia Padilla, Ester; Grau Vilalta, Maria Dolors

2017-01-01

En este trabajo se estudia el nexo agua-energía en el tramo del río Llobregat desde Castellar de N’hug hasta Manresa. Se lleva a cabo una evaluación de la cantidad de energía necesaria en las estaciones potabilizadoras y depuradoras para adecuar el agua del río, además de determinar la cantidad de energía que generan las centrales mini-hidroeléctricas. Estos dos valores de energía finales son comparados para demostrar si se consume más energía que la que se genera, o al contrario. Se estud...

Eficiencia energética de los edificios: repercusión medioambiental

Directory of Open Access Journals (Sweden)

Maria Nieves Pacheco Jiménez

2009-06-01

Full Text Available Los recientes Planes, Estrategias y normas atinentes al fomento de la eficiencia energética en los edificios1 nacen en un contexto de preocupación por el cambio climático y sus consecuencias. Todos ellos persiguen la reducción de costes energéticos y la promoción de la sostenibilidad económica, política y ambiental. Un reflejo de esta inquietud por el bajo impacto ambiental puede observarse en el sector de la vivienda, cuyo consumo final de energía es muy elevado, y en la consiguiente intención de construir edificios bioclimáticos que aprovechen la energía del entorno. En aras a la consecución de estos objetivos, el Plan de Acción 2008-2012 impulsa una serie de medidas que recaen sobre el sector transporte, la industria, el sector residencial y el sector terciario, articulándose en torno a cuatro líneas de actuación: transversal, de movilidad, de edificios y de ahorro eléctrico. Este estudio aborda las pautas de ahorro y eficiencia energética propuestas para los edificios, tanto existentes como de nueva construcción, así como residenciales y del sector terciario. Para ello se hace imprescindible la remisión al concepto de “calidad” de los edificios, contemplado en la propia Exposición de Motivos de la Ley 38/1999, de Ordenación de la Edificación, y ligado estrechamente a la eficiencia energética de aquéllos.

The Primitive Thylakoid-Less Cyanobacterium Gloeobacter Is a Common Rock-Dwelling Organism.

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Jan Mareš

Full Text Available Cyanobacteria are an ancient group of photosynthetic prokaryotes, which are significant in biogeochemical cycles. The most primitive among living cyanobacteria, Gloeobacter violaceus, shows a unique ancestral cell organization with a complete absence of inner membranes (thylakoids and an uncommon structure of the photosynthetic apparatus. Numerous phylogenetic papers proved its basal position among all of the organisms and organelles capable of plant-like photosynthesis (i.e., cyanobacteria, chloroplasts of algae and plants. Hence, G. violaceus has become one of the key species in evolutionary study of photosynthetic life. It also numbers among the most widely used organisms in experimental photosynthesis research. Except for a few related culture isolates, there has been little data on the actual biology of Gloeobacter, being relegated to an "evolutionary curiosity" with an enigmatic identity. Here we show that members of the genus Gloeobacter probably are common rock-dwelling cyanobacteria. On the basis of morphological, ultrastructural, pigment, and phylogenetic comparisons of available Gloeobacter strains, as well as on the basis of three new independent isolates and historical type specimen, we have produced strong evidence as to the close relationship of Gloeobacter to a long known rock-dwelling cyanobacterial morphospecies Aphanothece caldariorum. Our results bring new clues to solving the 40 year old puzzle of the true biological identity of Gloeobacter violaceus, a model organism with a high value in several biological disciplines. A probable broader distribution of Gloeobacter in common wet-rock habitats worldwide is suggested by our data, and its ecological meaning is discussed taking into consideration the background of cyanobacterial evolution. We provide observations of previously unknown genetic variability and phenotypic plasticity, which we expect to be utilized by experimental and evolutionary researchers worldwide.

Situación energética de los hidrocarburos en el Perú

OpenAIRE

Rojas Lazo, Oswaldo; Rojas Rojas, Jorge; Salas Bacalla, Julio

2014-01-01

La tasa de crecimiento anual del consumo de energía en el mundo se incrementa a razón de 2 a 3%, teniendo a los hidrocarburos y el carbón como sus principales componentes. En el Perú las reservas probadas de energía son: gas (Camisea) con el 43% de la energía comercial, la hidroenergía 23,1%, los líquidos de gas natural con el 14,7% y otros con el 19.2%. La balanza comercial energética en el Perú es negativa, la producción de petróleo en los últimos años está descendiendo mientras que la prod...

Los balances energéticos en la producción agropecuaria.

OpenAIRE

Yepes Jaramillo, Guillermo; Martínez Bustamante, Enrique

2011-01-01

A través de este ensayo se presenta otro enfoque de análisis de la energía utilizada por los vegetales para la producción agraria. Se parte de los conceptos fundamentales relacionados con la termodinámica y la manera como el flujo de energía incide sobre el follaje de la vegetación y se distribuye, a través de las hojas, en todo el dosel de comunidades de plantas. La vida en la tierra es mantenida por el flujo de energía radiado por el sol y que entra en la biosfera. Por medio de la fotosínte...

Energía y cambio climático

OpenAIRE

Wilfredo Bulege Gutiérrez

2014-01-01

Es claro que el crecimiento de la población, la extracción de materiales, la producción alimentaria y el incremento de energía para todas las actividades humanas nos conducen a un estado de colisión con las capacidades de la biosfera y los ecosistemas en el proceso de asegurar la provisión de bienes y servicios indispensables para la vida (1). La producción de energía convencional y contaminante es hoy una de las más graves en este escenario, tanto que la comunidad internacional y las potenci...

Extracción de energía del agua mediante generadores piezoeléctricos

OpenAIRE

Rodríguez Mendoza, Iker

2014-01-01

El desarrollo del Proyecto consiste, por una parte, en el estudio sobre la respuesta de los materiales piezoeléctricos como generadores de energía en un entorno acuoso que está sometido a variaciones de potencial y, por otra, en el estudio técnico y económico de un equipo basado en la utilización esta fuente de energía y su comercialización en el mercado energético. Esta energía es la que se obtiene de la fuerza de arrastre del agua al desplazarse a causa del movimiento ondulatorio de las ol...

Cuantificación del potencial energético undimotriz en las costas del Caribe colombiano

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Jaime P

2017-11-01

Full Text Available En este documento se describen los avances en la cuantificación de la energía de las olas de la costa caribeña colombiana. La metodología utilizada servirá como punto de partida para establecer el potencial energético en Colombia para este tipo de suministro energético. En la actualidad, el potencial energético teórico estimado en las ondas de la costa cercana en la costa atlántica es de aproximadamente 1107 MW y esto fue posible con datos que se han recogido y procesado desde enero de 2014. Las ecuaciones que tienen en cuenta variables tales como: la densidad del agua de mar, la temperatura y la velocidad del viento en la zona. También muestra el progreso del diseño del sistema Near Shore para la verificación del potencial de energía de las olas que consiste en un dispositivo que transforma la energía cinética de las ondas del mar en energía potencial gravitacional que se va a usar para mover un generador de corriente alterna.

Kinetic Simulations of Plasma Energization and Particle Acceleration in Interacting Magnetic Flux Ropes

Science.gov (United States)

Du, S.; Guo, F.; Zank, G. P.; Li, X.; Stanier, A.

2017-12-01

The interaction between magnetic flux ropes has been suggested as a process that leads to efficient plasma energization and particle acceleration (e.g., Drake et al. 2013; Zank et al. 2014). However, the underlying plasma dynamics and acceleration mechanisms are subject to examination of numerical simulations. As a first step of this effort, we carry out 2D fully kinetic simulations using the VPIC code to study the plasma energization and particle acceleration during coalescence of two magnetic flux ropes. Our analysis shows that the reconnection electric field and compression effect are important in plasma energization. The results may help understand the energization process associated with magnetic flux ropes frequently observed in the solar wind near the heliospheric current sheet.

Evaluation of the participation of ferredoxin in oxygen reduction in the photosynthetic electron transport chain of isolated pea thylakoids.

Science.gov (United States)

Kozuleva, Marina A; Ivanov, Boris N

2010-07-01

The contribution to reduction of oxygen by ferredoxin (Fd) to the overall reduction of oxygen in isolated pea thylakoids was studied in the presence of Fd versus Fd + NADP(+). The overall rate of electron transport was measured using a determination of Photosystem II quantum yield from chlorophyll fluorescence parameters, and the rate of oxidation of Fd was measured from the light-induced redox changes of Fd. At low light intensity, increasing Fd concentration from 5 to 30 microM in the absence of NADP(+) increased the proportion of oxygen reduction by Fd from 25-35 to 40-60% in different experiments. This proportion decreased with increasing light intensity. When NADP(+) was added in the presence of 15 microM Fd, which was optimal for the NADP(+) reduction rate, the participation of Fd in the reduction of oxygen was low, no more than 10%, and it also decreased with increasing light intensity. At high light intensity, the overall oxygen reduction rates in the presence of Fd + NADP(+) and in the presence of Fd alone were comparable. The significance of reduction of dioxygen either by water-soluble Fd or by the membrane-bound carriers of the photosynthetic electron transport chain for redox signaling under different light intensities is discussed.

La energía nuclear y la industria en Francia

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Roux, A.

1980-09-01

Full Text Available In this article an analysis is made of the favorable effects for industry involved in the development of nuclear energy and the interaction between them. Reference is made to the problem of energy supply in France and the need for an effort in energy savings, to the development of new sources and priority in the establishment of an important program of nuclear power plants. Also, an analysis is made of the role of Industry, the Atomic Energy and Electricity Commission of France in the supply and processing of the nuclear materials. Finally, a general review of the manpower and technical means presently available is made, as well as an examination of the investments foreseen for local development of this energy.

En este artículo se analizan los efectos favorables que para la Industria tiene el desarrollo de la energía nuclear y las interacciones entre ambas. Se hace referencia al problema del aprovisionamiento energético en Francia y a la necesidad de un esfuerzo en materia de ahorro de energía, al desarrollo de nuevas fuentes y a la prioridad en el establecimiento de un importante programa de centrales nucleares. También es analizado el papel de la Industria, la Comisaría de Energía Atómica y Electricidad de Francia en el abastecimiento y en la transformación de los materiales nucleares. Por último, se hace un repaso general de los medios humanos y técnicos con que se cuenta en la actualidad, así como de las inversiones previstas para un desarrollo nacional de esta energía.

Costo energético de las labores de preparación de suelo en Cuba

OpenAIRE

Pedro Paneque Rondón; Dailyn Soto León

2007-01-01

El objetivo fundamental del trabajo fue determinar el costo energético de las operaciones agrícolas mecanizadas y comparar los costos energéticos de los distintos tamaños (anchos de trabajo) de los aperos más utilizados en el país para la preparación de suelo, testando la hipótesis de que el costo energético expresado en MJ/ha es independiente del tamaño del equipo. Los resultados de la investigación permitieron llegar a las siguientes conclusiones: los mayores costos energéticos cor...

The Roles of Fluid Compression and Shear in Electron Energization during Magnetic Reconnection

Science.gov (United States)

Li, Xiaocan; Guo, Fan; Li, Hui; Birn, Joachim

2018-03-01

Particle acceleration in space and astrophysical reconnection sites is an important unsolved problem in studies of magnetic reconnection. Earlier kinetic simulations have identified several acceleration mechanisms that are associated with particle drift motions. Here, we show that, for sufficiently large systems, the energization processes due to particle drift motions can be described as fluid compression and shear, and that the shear energization is proportional to the pressure anisotropy of energetic particles. By analyzing results from fully kinetic simulations, we show that the compression energization dominates the acceleration of high-energy particles in reconnection with a weak guide field, and the compression and shear effects are comparable when the guide field is 50% of the reconnecting component. Spatial distributions of those energization effects reveal that reconnection exhausts, contracting islands, and island-merging regions are the three most important regions for compression and shear acceleration. This study connects particle energization by particle guiding-center drift motions with that due to background fluid motions, as in the energetic particle transport theory. It provides foundations for building particle transport models for large-scale reconnection acceleration such as those in solar flares.

Análise dos impactos energéticos e econômicos do programa brasileiro de etiquetagem energética (PBE/Inmetro em coletores solares térmicos do Brasil

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João Pedro Stefano Marchesini Fonseca

2018-01-01

Full Text Available O presente estudo avalia os impactos energéticos e econômicos do uso de coletores solares térmicos planos fechados, típicos do setor residencial, nas diferentes regiões geográficas do Brasil, considerando as classes de eficiência energética do Programa Brasileiro de Etiquetagem Energética – PBE/INMETRO. As avaliações energéticas mostraram que todas as classes de coletores solares, de A (mais eficiente a E (menos eficiente, apresentam significativos ganhos energéticos, em substituição aos chuveiros elétricos. Foi definida uma cidade representativa para cada região geográfica do país, bem como sua temperatura média ambiente e nível de radiação mensal, o volume diário de água do banho a ser aquecida pelo sistema e o chuveiro elétrico e também a área média de painel solar para cada residência. Posteriormente, foram coletadas as informações de custos dos modelos representativos em relação as classes de eficiência energética, bem como taxa de juros e tarifas de energia elétrica e, assim, foram calculadas as frações solares anuais. As análises econômicas, utilizando a ferramenta de Benefício Anual Líquido – BAL, mostraram que nem sempre é viável o consumidor residencial utilizar equipamentos mais eficientes, classe A (com o Selo PROCEL.

Vulnerabilidad energética en la metrópoli de Buenos Aires

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Silvina Carrizo

2014-06-01

Full Text Available Argentina declaró el uso racional y la eficacia energética una prioridad nacional, en consonancia con las recomendaciones de la Agencia Internacional de la Energía. Buenos Aires se ha comprometido con varios programas internacionales de preparación al cambio climático. Así a distintas escalas surgen iniciativas para modificar las condiciones y modalidades de aprovisionamiento y consumo energéticos, que revelan la precariedad y vulnerabilidad del sistema y los servicios. Este trabajo presenta una reflexión sobre los cambios que se dan en ese sentido, mostrando los inconvenientes del modelo energético argentino en Buenos Aires y las estrategias o medidas que tienden a revertirlos y a preparar la ciudad para situaciones críticas. En general, se trata de iniciativas que se implementan individual o parcialmente, sin que haya un plan integral promovido a escala colectiva. Las correcciones resultan marginales en el conjunto sin aliviar los problemas que se agravan por el crecimiento vertiginoso de las demandas. Entonces la continuidad del modelo energético argentino basado en hidrocarburos, para abastecer infraestructura que trabaja al límite de su capacidad y servir territorios que no se han preparado para las posibles crisis, explicaría la vulnerabilidad del sistema de abastecimiento metropolitano.

Desarrollo metodológico a partir de mosaicos urbanos para evaluar la eficiencia energética y el aprovechamiento de la energía solar en el marco de la sustentabilidad urbana

Directory of Open Access Journals (Sweden)

Graciela Melisa Viegas

Full Text Available En Argentina, la producción y reciclado de los edificios ha crecido significativamente en los últimos años, correspondiendo el mayor porcentaje a los residenciales. En este sentido es indispensable desarrollar herramientas analíticas que permitan comprender y monitorear los procesos involucrados en el fenómeno de la urbanización y cuantificar sus consecuencias energético-ambientales. El presente trabajo desarrolla una metodología que estudia, a partir de una unidad representativa (mosaico urbano, la aptitud de los distintos sectores de la ciudad para el aprovechamiento energético de la radiación solar en las diferentes texturas urbanas y sus áreas de disipación térmica, determinando el potencial energético de las mismas. Para ello se desarrolla: (a la definición conceptual de "mosaico urbano", su utilidad y su definición técnica; (b la evaluación de las herramientas para el procesamiento, la modelización espacial y energética de mosaicos; y (c un ejemplo de aplicación de la metodología. Los resultados verifican el desarrollo conceptual y la factibilidad de la metodología aplicable a un caso testigo de la ciudad de La Plata, Buenos Aires, Argentina (latitud 34°55 S; longitud 57°57 O, y permiten realizar estimaciones de la potencialidad para hacer eficiente el uso de la energía y aprovechar la energía solar (se obtuvo un 44,3% de ahorro de energía en calefacción.

Membrane potential and microsecond to millisecond delayed light emission after a single excitation flash in isolated chloroplasts

International Nuclear Information System (INIS)

Jursinic, P.; Govindjee; Wraight, C.A.

1978-01-01

The effect of light-induced and salt-jump induced membrane potential on microsecond and millisecond delayed light emission from chloroplasts, following a single 10 ns flash, have been studied. Microsecond delayed light emission is shown to be independent of the membrane potential contrary to proposals that the activation energy for delayed light emission can be modulated by transmembrane electric fields. This result is discussed in terms of the possible origin of this short-lived emission. Millisecond delayed light after a single excitation flash is enhanced by membrane potential only if a proton gradient is present. By measuring changes in ms delayed light caused by simultaneous injection of KCl and Na-benzoate (which creates a proton gradient) in the presence of valinomycin, the light-induced potential generated across the thylakoid membrane by a single excitation flash was calibrated and found to be 128 +- 10 mV in agreement with the recent measurements of Zickler and Witt, (FEBS Lett. 66, 142-148 (1976)), based on voltage-dependent ionophores. It is concluded that the secondary charges that give rise to ms delayed light, after a single flash, do not fully span the membrane. (author)

La Seguridad Energética y la Estrategia Global de Seguridad de la Unión Europea

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Ruben Herrero

2016-10-01

Full Text Available El presente artículo plantea una definición ampliada del concepto de seguridad energética, yendo más allá del concepto clásico establecido por la Agencia Internacional de la Energía, incorporando cuestiones relativas a la eficiencia energética, la aceptabilidad del modelo energético y los retos que impone el cambio climático, pero sin perder de perspectiva las exigencias y las dinámicas competitivas económicas globales. Sobre la base de este concepto ampliado, se examina la evolución de la seguridad energética en el marco de la Unión Europea, con una atención particular a cómo se concibe la seguridad energética en la Estrategia Global de Seguridad de 2016.

Iluminación con Energía Solar Fotovoltaica para Autoservicios en Bogotá

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Wilmar Giovani Santamaría

2015-07-01

Full Text Available Este artículo presenta un estudio técnico y económico sobre el uso de energía fotovoltaica para iluminación en dos (2 autoservicios en la ciudad de Bogotá. Se analizan diferentes aspectos a tener en cuenta, como la radiación solar mínima sobre el área considerada y los consumos en iluminación con energía convencional. Se estima que, al realizar el cambio de iluminación de bombillos fluorescentes a bombillos LED y establecer como fuente primaria las baterías previamente alimentadas con energía fotovoltaica, se reduce el consumo de energía eléctrica de manera considerable en iluminación. Con esta hipótesis, se plantean tres opciones de sistemas fotovoltaicos autónomos para cada uno de los autoservicios con todos los elementos necesarios para el mejor funcionamiento, el estudio económico de cada opción y un estimativo del ahorro energético.

Perspectivas del potencial energético de la biomasa en el marco global y latinoamericano

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Julián Rodrigo Quintero González

2015-06-01

Full Text Available El calentamiento global y los cambios climáticos que éste conlleva han fomentado desde hace algunos años la exploración de otros tipos de obtención energética para disminuir el uso del combustible fósil, siendo éste último uno de los principales causantes de dicho problema ambiental. El presente artículo expone algunas investigaciones recientes sobre la bioenergía u obtención de energía a partir de biomasa, considerada como energía limpia. Se abarcan temáticas como la bioenergía y sus posibilidades desde el punto de vista energético, teniendo en cuenta las expectativas de producción según su potencial o productividad energética, además del aporte que este tipo de tecnología hace a la disminución de la huella ecológica.

Estimación del potencial de energías renovables en el estado de Sonora

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Jorge Luis Taddei Bringas

2016-06-01

Full Text Available La etapa de uso de combustibles fósiles está llegando a su fin, debido principalmente a la escasez y problemas de contaminación que originan. En la actualidad existe una marcada tendencia en aprovechar las fuentes renovables de energía, por su bajo impacto ambiental y menor emisión de gases de efecto invernadero (GEI, lo cual contribuye a independizar las políticas energéticas locales de las del mercado global, basadas en la supremacía petrolera. Para obtener el mayor provecho de las energías renovables, es importante determinar el potencial de los distintos recursos energéticos existentes en una región. En este trabajo se presenta una relación del potencial para explotar energías renovables en el estado de Sonora, México, como un paso previo para establecer acciones y políticas que busquen su posible utilización a gran escala.

Energía de oleaje en la isla de Tenerife

OpenAIRE

Imaz Gómez, Mario

2016-01-01

El objeto de este proyecto es realizar todos los estudios necesarios para la construcción de la primera fase de un parque de dispositivos de extracción de energía undimotriz que permita obtener información fiable y necesaria sobre el comportamiento de los dispositivos en grupo y poder ver si el rendimiento es el esperado para posteriormente realizar las otras dos fases con el fin de abastecer a la ciudad de Puerto de la Cruz, situada en el norte de la isla de Tenerife. Actualmente las energía...

Eficiencia energética en el sector residencial de la ciudad de Cuenca, Ecuador

OpenAIRE

Baquero Larriva, María Teresa; Quesada Molina, Juan Felipe

2016-01-01

El objetivo de la presente investigación fue determinar en qué medida se puede reducir el consumo de energía en el sector residencial de la ciudad de Cuenca, manteniendo óptimas condiciones de confort. El estudio se centra en la definición de indicadores de eficiencia energética para la vivienda, mediante la determinación de la demanda de energía y la definición de los factores de mayor consumo, usando un enfoque cualitativo y cuantitativo. Se realizaron encuestas en 280 viviendas del sector ...

Evaluación del potencial energético del oleaje en la costa sur del Golfo de México

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Alejandro González-Carrillo

2015-01-01

Full Text Available Hallar nuevas fuentes de energía es uno de los retos que trajo consigo el siglo XXI. En este tr abajo se hace un análisis sobre la energía de las olas, la cual presenta varia s ventajas significativas con r especto a otras fuentes de energ ías basadas en combustibles fós iles e, inclusive, otras fuentes renovables de energía. De entre estas ventajas de stacan el bajo impacto ambiental y su alta densidad energética, respectivamente. La energía de las olas del mar se considera ca da vez en más países como un recurso renovable importante y sob re todo prometedor. El objetivo de este trabajo es la evaluación del po tencial energético de las olas en la costa sur del Golfo de Méx ico; en él se observó el comportamiento del olea je y se obtuvo que la potenci a media anual disponible es de 55.91 W/m. Adicionalmente, se de staca el comportamiento estacional de las olas en la región; pues, en es te punto, la estación más energética es otoño y la menos energé tica es primavera, lo cual difiere de la tendencia mundial, en la que i nvierno y verano son la más y la menos energética, respectivamente.

Implicaciones ambientales de las tecnologías de energía renovable

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Jan Mahirt-Smith

2011-12-01

Full Text Available Las tecnologías de energía renovable como la eólica, la solar y la biomasa, hacen un uso del suelo más intenso que las de combustibles fósiles tradicionales y, geográficamente, sus implicaciones ambientales son más heterogéneas, por lo que presentan un gran desafío para las técnicas de evaluación de su ciclo de vida. Este trabajo presenta los resultados de una investigación bibliográfica alrededor de los siguientes temas: 1 cambios en el uso del suelo debido a la mayor producción de energía renovable; 2 impactos del uso de suelo; 3 variabilidad geográfica en el inventario de datos; y 4 efectos de la distribución de energía. Además, se revisa el grado de investigación que actualmente se aplica acerca de las tecnologías de energía renovable en campos como el eólico, el solar y la bioenergía y en la evaluación del ciclo de vida en general.

Plasma Membrane H(+)-ATPase Regulation in the Center of Plant Physiology.

Science.gov (United States)

Falhof, Janus; Pedersen, Jesper Torbøl; Fuglsang, Anja Thoe; Palmgren, Michael

2016-03-07

The plasma membrane (PM) H(+)-ATPase is an important ion pump in the plant cell membrane. By extruding protons from the cell and generating a membrane potential, this pump energizes the PM, which is a prerequisite for growth. Modification of the autoinhibitory terminal domains activates PM H(+)-ATPase activity, and on this basis it has been hypothesized that these regulatory termini are targets for physiological factors that activate or inhibit proton pumping. In this review, we focus on the posttranslational regulation of the PM H(+)-ATPase and place regulation of the pump in an evolutionary and physiological context. The emerging picture is that multiple signals regulating plant growth interfere with the posttranslational regulation of the PM H(+)-ATPase. Copyright © 2016 The Author. Published by Elsevier Inc. All rights reserved.

Actividad económica, consumo final de energía y requerimientos de energía primaria en Cataluña, 1990-2005. Análisis mediante el uso de los balances energéticos desde una perspectiva input-output

OpenAIRE

Jordi Roca Jusmet; Vicent Alcántara Escolano; Emilio Padilla Rosa

2007-01-01

Este trabajo analiza la evolución de los consumos finales de energía en Cataluña durante el periodo 1990-2005. En conjunto, los consumos finales de energía crecen por encima del crecimiento del PIB en términos reales. La disponibilidad actual de datos permite una desagregación en cinco actividades: sector primario; sector industrial; sector servicios; transporte; y sector doméstico. Los aumentos relativos más importantes se dan en los sectores servicios, doméstico y transporte. Es esta última...

Radiation signatures from a locally energized flaring loop

International Nuclear Information System (INIS)

Emslie, A.G.; Vlahos, L.; and Institute for Plasma Research, Stanford University)

1980-01-01

We calculate the radiation signatures from a locally energized solar flare loop, at a variety of wavelengths. Our calculations depend strongly on the physical properties of the energy release mechanism which we qualitatively discuss

Characterization of chloroplast phosphoproteins controlling manganese use efficiency using quantitative proteomics

DEFF Research Database (Denmark)

Petersen, Jørgen; Sprenger, Richard Remko; Rogowska-Wrzesinska, Adelina

Manganese is important for molecular functions in plants, i.e. as a co-factor in enzymes and in the oxygen evolving complex of photosystem II, located like most of the photosynthetic machinery, in the thylakoid membranes of chloroplasts. Soils that lack plant available micronutrients such as mang......Manganese is important for molecular functions in plants, i.e. as a co-factor in enzymes and in the oxygen evolving complex of photosystem II, located like most of the photosynthetic machinery, in the thylakoid membranes of chloroplasts. Soils that lack plant available micronutrients...... involved in manganese use efficiency, focusing on the phosphoproteome from thylakoid preparations from two barley genotypes, manganese efficient (Vanessa) and inefficient (Antonia) genotype. Experimental: By monitoring the photosynthetic efficiency (Fv/Fm) a decline in activity is observed as a consequence...

Crystal structure of the plasma membrane proton pump

DEFF Research Database (Denmark)

Pedersen, Bjørn P.; Buch-Pedersen, Morten Jeppe; Morth, J. Preben

2007-01-01

A prerequisite for life is the ability to maintain electrochemical imbalances across biomembranes. In all eukaryotes the plasma membrane potential and secondary transport systems are energized by the activity of P-type ATPase membrane proteins: H1-ATPase (the proton pump) in plants and fungi1......-3, and Na1,K1-ATPase (the sodium-potassium pump) in animals4. The name P-type derives from the fact that these proteins exploit a phosphorylated reaction cycle intermediate of ATP hydrolysis5.The plasma membrane proton pumps belong to the type III P-type ATPase subfamily, whereas Na1,K1-ATPase and Ca21......- ATPase are type II6. Electron microscopy has revealed the overall shape of proton pumps7, however, an atomic structure has been lacking. Here we present the first structure of a P-type proton pump determined by X-ray crystallography. Ten transmembrane helices and three cytoplasmic domains define...

Membrane potential of mitochondria from the liver of irradiated rats

International Nuclear Information System (INIS)

Fomenko, B.S.; Kaminin, A.N.; Elfimova, I.A.; Akoev, I.G.

1977-01-01

Measurements of the membrane potential of rat liver mitochondria 1 hour after irradiation with 800 R dose showed a decrease of its value. The potential decreased against the background of the activation of the generating mechanisms (the electron transport chain and ATP-ases). During energization of the membranes by the electron transport chain similar effect has been observed with different oxidation substrates (NAD linked substrates and succinate). It suggests that similar causative factors are at the basis of the changes observed. It is quite possible that the increase in the rate of both mitochondria respiration and ATP hydrolysis after the irradiation of animals was a consequence of the radiation-induced decrease in the potential value. (author)

Variaciones de voltaje: Mala calidad de la energía

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Norberto Rodríguez Barallobre

2011-02-01

Full Text Available Este es el primero de una serie de artículos encaminados a tratar la creciente problemática de la calidadde la energía en las instalaciones industriales debida al incremento del uso de la electrónica y suscomponentes contaminantes de la energía eléctrica entendida como el producto de la onda de corriente yla de voltaje. Además, se ofrece un procedimiento para estimar el costo de las pérdidas técnicas ytecnológicas por concepto de una mala calidad de la energía así como, algunas recomendaciones paramitigar estas pérdidas millonarias en el sector industrial.  This is a first of a series of papers toward to treat the power quality growing problematical in industrialinstallations networks, due to increasing use of electronic and its polluting components, learned as aproduct of the current and voltage wave, Also is offered a procedure to estimate the technical andtechnological losses cost due to the low quality energy, some recommendations to mitigate this millonairelosses in the industrial sector

El desarrollo de las energías renovables y el paisaje: algunas bases para la implementación de la Convención Europea del Paisaje en la Política energética española

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Marina Frolova

2008-01-01

Full Text Available Desde el inicio del proceso de reforma de la política energética de la Unión Europea, los paisajes emergentes a partir de generación de electricidad con energías renovables suscitan un interés creciente. España se caracteriza por una implantación muy exitosa de las políticas europeas en materia de energías renovables. Sin embargo, la proliferación de aerogeneradores y placas fotovoltaicas en espacios agrícolas o improductivos conlleva la destrucción de numerosos paisajes muy valiosos. Por lo que la nueva sensibilidad hacia los paisajes se está convirtiendo en el mayor obstáculo para el desarrollo de las energías renovables. El objetivo de este artículo es explorar en la relación que se establece entre la implantación de las energías renovables y la evolución de las políticas paisajísticas. Para ello, se analiza el desarrollo que han experimentado las políticas de energías renovables en Europa y en España; se estudian las nuevas formas democráticas de gestión del territorio que plantea la Convención Europea del Paisaje. Por último, se tratan determinados temas de la inclusión del paisaje en las políticas de energías renovables en España, comentando algunos ejemplos en los que se detectan nuevas estrategias en la implantación de proyectos de energías renovables que pueden reducir los impactos sobre el paisaje.

Importancia de la energía para el crecimiento económico de México

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Flory A. Dieck Assad

2014-01-01

Full Text Available Esta investigación analiza la productividad agregada de la mano de obra y del capital en México entre los años 1993 y 2013, con el fin de identificar las variables que influyen en su comportamiento, especialmente la energía. Esto se lleva a cabo mediante una función de producción agregada que logra identificar la influencia del acervo utilizado de capital, el trabajo remunerado, los cambios tecnológicos y la energía sobre la productividad agregada real promedio de la mano de obra y el capital y, por ende, del crecimiento potencial del PIB (producto interno bruto. Asimismo, se introduce el tema de precios de la energía, identificando su impacto directo en el uso de energía y el indirecto en la productividad y el crecimiento económico. Este análisis culmina con la definición de las perspectivas de la Reforma energética a la luz de los resultados de esta investigación, vislumbrando los desafíos y retos futuros.

MapA, an iron-regulated, cytoplasmic membrane protein in the cyanobacterium Synechococcus sp. strain PCC7942.

Science.gov (United States)

Webb, R; Troyan, T; Sherman, D; Sherman, L A

1994-08-01

Growth of Synechococcus sp. strain PCC 7942 in iron-deficient media leads to the accumulation of an approximately 34-kDa protein. The gene encoding this protein, mapA (membrane-associated protein A), has been cloned and sequenced (GenBank accession number, L01621). The mapA transcript is not detectable in normally grown cultures but is stably accumulated by cells grown in iron-deficient media. However, the promoter sequence for this gene does not resemble other bacterial iron-regulated promoters described to date. The carboxyl-terminal region of the derived amino acid sequence of MapA resembles bacterial proteins involved in iron acquisition, whereas the amino-terminal end of MapA has a high degree of amino acid identity with the abundant, chloroplast envelope protein E37. An approach employing improved cellular fractionation techniques as well as electron microscopy and immunocytochemistry was essential in localizing MapA protein to the cytoplasmic membrane of Synechococcus sp. strain PCC 7942. When these cells were grown under iron-deficient conditions, a significant fraction of MapA could also be localized to the thylakoid membranes.

Energía eólica en Argentina : un análisis económico del derecho

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Cecilia Giralt

2013-10-01

Full Text Available El abastecimiento energético con base en fuentes no renovables es un tema altamente estratégico en las agendas de los Estados. El petróleo se está agotando y probablemente las existencias comprobadas no alcanzarán para abastecer el consumo mundial, provocando una serie de impactos sociopolíticos y económicos a nivel global. Esto ha llevado a los gobiernos a replantear sus matrices energéticas, apostando a las energías renovables como un camino posible para lograr una mayor autonomía energética. La Argentina, con una matriz energética desbalanceada e hidrocarburo-dependiente, se ha visto empujada también a reformular su horizonte energético a partir de fuentes renovables para lograr una mayor independencia del recurso fósil. Los marcos regulatorios utilizados para este cambio son el objeto de análisis de este artículo, el cual también intenta contribuir con algunas recomendaciones para un futuro muy cercano.

Problemas institucionales de las energías renovables en México

OpenAIRE

Samuel Brugger; Ma. Elena Nancy Dávila Moreno; Manuel Francisco Llamas Galván

2011-01-01

Este ensayo trata de explicar los problemas institucionales y jurídicos que han limitado el aprovechamiento de dichas energías alternativas. El trabajo presenta la situación actual de México; después analiza el potencial que tiene el país. De ahí se pasa al estudio de la problemática institucional y jurídica que no ha logrado fomentar la promoción de energías renovables en México.

Problemas institucionales de las energías renovables en México

Directory of Open Access Journals (Sweden)

Samuel Brugger

2011-09-01

Full Text Available Este ensayo trata de explicar los problemas institucionales y jurídicos que han limitado el aprovechamiento de dichas energías alternativas. El trabajo presenta la situación actual de México; después analiza el potencial que tiene el país. De ahí se pasa al estudio de la problemática institucional y jurídica que no ha logrado fomentar la promoción de energías renovables en México.

En cumplimiento con la orden ejecutiva del presidente Trump sobre la Independencia Energética

Science.gov (United States)

Acciones reglamentarias tomadas por la EPA, incluyendo audiencias públicas, para implementar la Orden Ejecutiva sobre la Independencia Energética y la propuesta derogación del Plan de Energía Limpia.

Herbal Energizers: Speed By Any Other Name.

Science.gov (United States)

Jenkins, Andrew P.

This guide focuses on over-the-counter (OTC) stimulants sold to high school aged athletes and dieters as "herbal energizers," food supplements, and fatigue reducers. While advertising often makes them appear healthful and harmless, all of these stimulants belong in the class "sympathomimetic amines," so called because they…

Perspectivas de la situación energética mundial. Las oportunidades para Colombia

OpenAIRE

Arturo Infante Villarreal

2007-01-01

Casi la cuarta parte de la energía que consume Estados Unidos proviene de petróleo importado y sólo el 6% se origina en fuentes renovables, aunque el país produce 20% de la polución ambiental mundial y tiene sólo 4% de la población total. Los biocombustibles son una fuente potencial de energía renovable para Estados Unidos, y el resto del mundo, porque tienen un balance energético y ambiental bastante favorable. Si las condiciones de precios son adecuadas para los productores de las materias ...

Asturias en el sistema energético: del nacionalismo a la globalización

OpenAIRE

Maurín Álvarez, Manuel

2011-01-01

Con una demanda energética regional estancada y al mismo tiempo en que se clausuran las últimas explotaciones mineras, principales proveedoras de materias primas energéticas autóctonas, Asturias se aventura a la construcción de infraestructuras de generación y transporte que permitirían duplicar en los próximos años una producción eléctrica que ya es excedentaria. La región se convierte así en una especie de «vientre de alquiler» energético, especializada en generar, con materias primas impor...

Mejora de la eficiencia energética en una vivienda

OpenAIRE

Díaz Oliva, Marc

2013-01-01

El objetivo de este proyecto es la mejora de la eficiencia energética de la vivienda este objetivo me viene por una estancia en Alemania donde todas las viviendas están concebidas para obtener la máxima eficiencia y por consiguiente ahorro una de las cosas que más me llamo la atención fue la implantación de energías renovables ya que las horas de luz son menores a las obtenidas en España por este motivo quise comprobar cuanto se podía mejorar la eficiencia en mi vivienda y s...

Cómo producen energía las células

OpenAIRE

Carlos Alberto Ordoñez

2014-01-01

El adenosín trifosfato (ATP), es la moneda energética de los seres vivos. Para poder ser sintetizado, los organismos requieren oxidar los sustratos energéticos de la dieta, proteínas, grasas y carbohidratos. Inicialmente estas sustancias tienen vías metabólicas separadas hasta alcanzar en su degradación un metabolito común que es el acetil CoA. A partir de este punto entran al ciclo de Krebs, con producción de CO2 e hidrogeniones, estos últimos se transportan por óxido reducción a la cadena r...

Estudio de la energía y el medio ambiente: una propuesta didáctica computarizada

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Edwin Francisco Bonza Camargo

2009-09-01

Full Text Available El objetivo de este proyecto es desarrollar un material educativo computarizado, MEC, para la enseñanza de la energía; contribuyendo de esta manera a solucionar una de las grandes falencias del sistema educativo colombiano: la falta de material didáctico en las aulas de las escuelas y colegios. Además, con la aplicación de este material se aporta a la creación de conciencia en la población escolar hacia un uso más racional de la energía en pro del medio ambiente. El software se diseñó con base en el manejo de lecturas, imágenes, sonidos, videos y animaciones que permiten al estudiante aprender y conceptuar con mayor facilidad sobre un tema tan importante como lo es el de los recursos energéticos renovables y no renovables, abarcando temas tan importantes como la energía solar térmica, que es una posible solución a la crisis energética que se avecina. También, resalta la importancia que tiene la búsqueda de nuevas fuentes de energía que no degraden el medio ambiente.

Development of high electrical resistance persistent current switch for high speed energization system

International Nuclear Information System (INIS)

Jizo, Y.; Furuta, Y.; Nakashima, H.

1986-01-01

Japanese National Railways is now developing a superconducting magnetically-levitated train system. A persistent current switch is incorporated in the super-conducting magnet used in the magnetically-levitated train. In recent years, the switch has been required to have higher electrical resistance during its off-state in order to realize the high speed energization/de-energization system of the superconducting magnets. The system aims to decrease evaporation volume of liquid helium during the energization/de-energization of the magnet, by means of energizing the superconducting magnet with high current increasing/decreasing rate. Consequently, it would be possible to decrease the dependence of the on-board magnet system upon the ground cooling system. Through the development of a stable superconductive wire material and a coil structure for the persistent current switch using many small model switches which were produced in order to improve their current carrying capacities, the authors have succeeded in manufacturing the high electrical resistance persistent current switch whose electrical resistance was 5 ohms. The switch, of cylindrical shape, has a diameter of about 100mm, a length of about 100mm. These 5 ohm PCSs are now functioning in stable conditions being incorporated in the superconducting magnets of No.2 vehicle of MLU001 at the JNR's Miyazaki test track. Further, the authors are now developing the PCS of still higher resistance values, such as 50 ohms, through studies for stabilization in structural aspects of the winding and obtaining results therefrom

Gas exchange and leaf contents in bell pepper under energized water and biofertilizer doses

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Francisca R. M. Borges

2016-06-01

Full Text Available ABSTRACT The objective of this study was to evaluate the effect of energized water and bovine biofertilizer doses on the gas exchange and NPK contents in leaves of yellow bell pepper plants. The experiment was conducted at the experimental area of the Federal University of Ceará, in Fortaleza-CE, Brazil, from June to November 2011. The experiment was set in a randomized block design, in a split-plot scheme; the plots were composed of treatments with energized and non-energized water and the subplots of five doses of liquid biofertilizer (0, 250, 500, 750 and 1000 mL plant-1 week-1. The following variables were analyzed: transpiration, stomatal conductance, photosynthesis and leaf contents of nitrogen (N, phosphorus (P and potassium (K. Water energization did not allow significant increases in the analyzed variables. The use of biofertilizer as the only source of fertilization was sufficient to provide the nutrients N, P and K at appropriate levels for the bell pepper crop.

Redes de energía en la Argentina del siglo XXI. Proyectos locales innovadores

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Silvina Carrizo

2015-04-01

Full Text Available En Argentina se construyeron de forma pionera, extensas redes de electricidad, gas y combustibles. El 98% de los hogares están conectados a la red eléctrica y el 51% de la población tiene acceso al gas natural por red (INDEC 2012. A pesar de la cobertura energética amplia, aún persisten en el país algunas regiones -como el Noroeste de la Provincia de Buenos Aires NOBAdonde las redes no llegan o tienen menor densidad. La región NOBA, situada entre las ciudades de Rosario y Buenos Aires, que cuentan con infraestructura considerable para su aprovisionamiento, presenta redes eléctricas y gasíferas poco densas -especialmente hacia el interior- y escaso desarrollo de fuentes de energías alternativas. En materia de gas, faltan gasoductos troncales o regionales. En el sistema eléctrico, hay poca capacidad de generación y se necesita mayor interconexión. Desde distintos niveles se han promovido alternativas en materia de producción, transporte y distribución de energía, pero los avances aún no alcanzan para asegurar la resiliencia energética enla región NOBA. En un contexto de esta índole, actores locales se han organizado para satisfacer sus necesidades energéticas con proyectos nuevos de transporte de gas y de aprovechamiento de recursos locales renovables, con un potencial que aún no ha sido puesto en valor. Abordando proyectos energéticos locales y regionales, este trabajo propone reflexionar acerca de la nueva geografía que podría delinearse en la producción y circulación de la energía, más flexible, fiable y sustentable, fomentando la innovación y la productividad, así como la equidad regional.

Estimativa das necessidades energéticas em pacientes com doença renal crônica

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Juliana Cordeiro Dias Rodrigues

2013-02-01

Full Text Available Estabelecer as necessidades energéticas de pacientes com doença renal crônica é importante para que se possam tratar os distúrbios nutricionais encontrados nessa população. Segundo os guias de condutas voltados ao cuidado nutricional de pacientes com essa doença, a recomendação energética pode variar entre 30 e 40kcal/kg/dia. Contudo, trabalhos que avaliaram os componentes do gasto energético nos pacientes com doença renal crônica sugerem que as necessidades energéticas dessa população podem diferir do valor recomendado acima, a depender da condição clínica (presença de comorbidades, da modalidade de tratamento empregado e do nível de atividade física. Dessa forma, o presente trabalho tem como objetivo fazer uma revisão dos estudos sobre o gasto energético de pacientes com doença renal crônica, com o intuito de abordar as seguintes questões: (1 as atuais recomendações de energia para pacientes com doença renal crônica estão adequadas? (2 qual equação de predição poderia ser empregada para estimar as necessidades energéticas desse grupo de pacientes? Assim, esta revisão busca auxiliar o nutricionista ao estimar as necessidades energéticas de pacientes com doença renal crônica.

Costo energético de muros y techos utilizados en la zona sur de Tamaulipas

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Mireya Alicia Rosas Lusett

2015-01-01

Full Text Available El presente trabajo muestra los procedimientos y resultados obtenidos del análisis de la energía trasmitida en techos y muros de las viviendas seleccionadas de la zona sur del estado de Tamaulipas, una de las cinco áreas establecidas dentro del proyecto “Desarrollo y validación de una metodología para estimar los impactos en el ahorro de energía por el uso de sistemas pasivo-constructivos en la edificación para diferentes climas de México”. Este proyecto fue financiado por la Convocatoria S0019-2009-01 del Fondo Sectorial de Sustentabilidad Energética SENER-CONACYT con registro Nº 118665, cuyo objetivo en su tercera etapa de ejecución, consistió en hacer uso de la herramienta Ener-Habitat, la cual fue desarrollada durante la segunda fase del proyecto. Con dicho programa de cálculo se determinaron los gastos de energía, comparativa de cuatro sistemas constructivos para muros y tres sistemas constructivos para losas utilizadas en la zona sur de Tamaulipas. Con la información obtenida y mediante el uso de la metodología desarrollada para estimar los impactos en el ahorro de energía, se evaluó el costo energético de cada uno de los sistemas constructivos. Con los resultados obtenidos se pudo determinar cuál era el muro y techo de menor gasto de energía para la zona de estudio. Adicionalmente se realizó un estudio de la influencia de la absortancia solar de la superficie exterior de los muros, cuyos resultados darán la pauta para diseñar una vivienda que pretende sea adecuada y cómoda al clima cálido húmedo que prevalece en el área.

Proyecto de vivienda energéticamente sostenible situada en Ontinyent (Valencia). Instalación fotovoltaica.

OpenAIRE

MOLLÁ CALABUIG, SERGIO

2015-01-01

[ES] Se van a diseñar las instalaciones necesarias para que una vivienda unifamiliar sea energéticamente sostenible. La única fuente de energía disponible es la solar Se calcualrán las instalaciones para dos opciones. 1. Vivienda conectada a la red eléctrica general. 2. Vivienda aislada de la red eléctrica. [ES] El objeto de este trabajo es el diseño y comparación, de las instalaciones necesarias para que una vivienda unifamiliar sea energéticamente sostenible, con la única fuen...

Estimación del potencial de energías renovables en el estado de Sonora

OpenAIRE

Jorge Luis Taddei Bringas; María de los Ángeles Navarrete Hinojosa; Pablo Daniel Taddei Arriola; Rafael Cabanillas López.

2016-01-01

La etapa de uso de combustibles fósiles está llegando a su fin, debido principalmente a la escasez y problemas de contaminación que originan. En la actualidad existe una marcada tendencia en aprovechar las fuentes renovables de energía, por su bajo impacto ambiental y menor emisión de gases de efecto invernadero (GEI), lo cual contribuye a independizar las políticas energéticas locales de las del mercado global, basadas en la supremacía petrolera. Para obtener el mayor provecho de las energía...

La vulnerabilidad energética asociada a la movilidad motorizada

Directory of Open Access Journals (Sweden)

Ana Sanz Fernández

2013-04-01

Full Text Available ResumenEl concepto de vulnerabilidad energética describe la situación a la que se pueden enfrentar aquellos niveles de renta cuyo patrón de movilidad deje de ser económicamente viable por el incremento de los costes del petróleo. Teniendo en cuenta que la movilidad laboral es un gasto prioritario para evitar la exclusión social que supone la pérdida del empleo, el aumento de los gastos en esa partida presupuestaria familiar puede derivar en dos situaciones, ambas involuntarias, que serían la necesidad de destinar una mayor cantidad de recursos al transporte (pudiendo entonces aparecer privaciones en otras esferas o la obligación de cambiar los patrones de movilidad. El objetivo de esta investigación es desarrollar este concepto, ponerlo en relación con dos conceptos directamente vinculados, exclusión social vinculada al transporte y pobreza energética, y aplicar en el área metropolitana de Madrid la metodología desarrollada, detectando los de espacios urbanos energéticamente vulnerables y explicitando las relaciones de este fenómeno con la disciplina.Palabras claveVulnerabilidad energética, exclusión social vinculada al transporte, pobreza energética, pico del petróleo, área metropolitana.AbstractThe concept of energy vulnerability describes the situation that may face those income levels that have a mobility pattern which is no longer economically viable due to rising oil costs. Given that labor mobility is a priority spending to avoid social exclusion caused by job loss, increased expenses in that family budget can result in two situations, both involuntary, that would be the need for a greater amount of resources to transport (in that case, deprivation can then appear in other areas or the obligation to change mobility patterns. The objective of this research is todevelop this concept, put on two concepts directly related, transport related social exclusion and fuel poverty, and applied in the Madrid metropolitan area

Proteomic Analysis of Chloroplast-to-Chromoplast Transition in Tomato Reveals Metabolic Shifts Coupled with Disrupted Thylakoid Biogenesis Machinery and Elevated Energy-Production Components1[W

Science.gov (United States)

Barsan, Cristina; Zouine, Mohamed; Maza, Elie; Bian, Wanping; Egea, Isabel; Rossignol, Michel; Bouyssie, David; Pichereaux, Carole; Purgatto, Eduardo; Bouzayen, Mondher; Latché, Alain; Pech, Jean-Claude

2012-01-01

A comparative proteomic approach was performed to identify differentially expressed proteins in plastids at three stages of tomato (Solanum lycopersicum) fruit ripening (mature-green, breaker, red). Stringent curation and processing of the data from three independent replicates identified 1,932 proteins among which 1,529 were quantified by spectral counting. The quantification procedures have been subsequently validated by immunoblot analysis of six proteins representative of distinct metabolic or regulatory pathways. Among the main features of the chloroplast-to-chromoplast transition revealed by the study, chromoplastogenesis appears to be associated with major metabolic shifts: (1) strong decrease in abundance of proteins of light reactions (photosynthesis, Calvin cycle, photorespiration) and carbohydrate metabolism (starch synthesis/degradation), mostly between breaker and red stages and (2) increase in terpenoid biosynthesis (including carotenoids) and stress-response proteins (ascorbate-glutathione cycle, abiotic stress, redox, heat shock). These metabolic shifts are preceded by the accumulation of plastid-encoded acetyl Coenzyme A carboxylase D proteins accounting for the generation of a storage matrix that will accumulate carotenoids. Of particular note is the high abundance of proteins involved in providing energy and in metabolites import. Structural differentiation of the chromoplast is characterized by a sharp and continuous decrease of thylakoid proteins whereas envelope and stroma proteins remain remarkably stable. This is coincident with the disruption of the machinery for thylakoids and photosystem biogenesis (vesicular trafficking, provision of material for thylakoid biosynthesis, photosystems assembly) and the loss of the plastid division machinery. Altogether, the data provide new insights on the chromoplast differentiation process while enriching our knowledge of the plant plastid proteome. PMID:22908117

Modelo para la Predicción Energética de una Instalación Hotelera

Directory of Open Access Journals (Sweden)

Adriana V. Acosta

2011-10-01

Full Text Available Resumen: Este artículo describe la obtención y validación de un modelo de predicción energética para el hotel Meliá Habana de la ciudad Habana en Cuba. El modelo obtenido emplea el método de series de tiempo radiantes para la determinación de la carga térmica de los bloques habitacionales de la instalación. El modelo es implementado en el lenguaje de programación MatLab®. La validación experimental del modelo se realiza con mediciones reales del consumo energético diario del hotel. El valor de uso del modelo obtenido es apreciable para estudios de comportamiento energético y para la implementación de estrategias avanzadas de control. Palabras clave: Modelado, Control de la Energía, Coeficientes de Temperatura, Validación

Monitoring, Analyzing and Assessing Radiation Belt Loss and Energization

Science.gov (United States)

Daglis, I.; Balasis, G.; Bourdarie, S.; Horne, R.; Khotyaintsev, Y.; Mann, I.; Santolik, O.; Turner, D.; Anastasiadis, A.; Georgiou, M.; Giannakis, O.; Papadimitriou, C.; Ropokis, G.; Sandberg, I.; Angelopoulos, V.; Glauert, S.; Grison, B., Kersten T.; Kolmasova, I.; Lazaro, D.; Mella, M.; Ozeke, L.; Usanova, M.

2013-09-01

We present the concept, objectives and expected impact of the MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Loss and Energization) project, which is being implemented by a consortium of seven institutions (five European, one Canadian and one US) with support from the European Community's Seventh Framework Programme. The MAARBLE project employs multi-spacecraft monitoring of the geospace environment, complemented by ground-based monitoring, in order to analyze and assess the physical mechanisms leading to radiation belt particle energization and loss. Particular attention is paid to the role of ULF/VLF waves. A database containing properties of the waves is being created and will be made available to the scientific community. Based on the wave database, a statistical model of the wave activity dependent on the level of geomagnetic activity, solar wind forcing, and magnetospheric region will be developed. Multi-spacecraft particle measurements will be incorporated into data assimilation tools, leading to new understanding of the causal relationships between ULF/VLF waves and radiation belt dynamics. Data assimilation techniques have been proven as a valuable tool in the field of radiation belts, able to guide 'the best' estimate of the state of a complex system. The MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Energization and Loss) collaborative research project has received funding from the European Union’s Seventh Framework Programme (FP7-SPACE-2011-1) under grant agreement no. 284520.

Liga de magnésio como material para bateria de alta densidade energética

OpenAIRE

Munhoz, Igor Polezi

2014-01-01

Orientador: Prof. Dr. Jorge Tomioka Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2014. No contexto energético, as mudanças climáticas e as crescentes crises energéticas aumentaram as preocupações e as pesquisas na área de acumuladores de energia, visando alcançar melhorias no cenário energético e ambiental global. Ao mesmo tempo, a sociedade tornou-se dependente do consumo de energia elétrica, sendo que falhas no fornec...

Action spectrum for inhibition by ultraviolet radiation of photosystem 2 activity in spinach thylakoids

International Nuclear Information System (INIS)

Bornman, J.F.; Bjoern, L.O.; Aakerlund, H.-E.

1984-01-01

The effect of ultraviolet (UV) radiation (half-band width 10 nm) in the wavelength range 248-340 nm on chlorophyll fluorescence from a thin layer of spinach thylakoid suspension was investigated. It was found that the parameter most sensitive to UV radiation was the rise time of variable fluorescence. The increase in rise time was proportional to UV photon fluence and was used for the determination of an action spectrum. The action spectrum falls off from a maximum at ca. 275 nm towards longer wavelengths and rises from a minimum at 260 nm towards shorter wavelengths. The results also suggest that the UV inhibition is mainly on the PS 2 oxidizing side. Possibly damage is also inflicted to the PS 2 reaction center. (orig.)

Proyecto de vivienda energéticamente sostenible situada en Almería. Instalación fotovoltaica.

OpenAIRE

CORBERÁ FERRANDO, JOSÉ Mª

2015-01-01

[ES] Se van a diseñar las instalaciones necesarias para que una vivienda unifamiliar sea energéticamente sostenible. La única fuente de energía disponible es la solar Se calcualrán las instalaciones para dos opciones. 1. Vivienda conectada a la red eléctrica general. 2. Vivienda aislada de la red eléctrica. Corberá Ferrando, JM. (2015). Proyecto de vivienda energéticamente sostenible situada en Almería. Instalación fotovoltaica. http://hdl.handle.net/10251/53541. TFGM

Celdas combustibles: una opción para la transformación descentralizada de energía

Directory of Open Access Journals (Sweden)

Julio Alberto Gavilán Yodú

2011-02-01

Full Text Available La solución a los problemas energéticos actuales y al progresivo deterioro del medio ambiente está estrechamenterelacionada con la elección de sistemas energéticos alternativos que sean capaces de garantizar el desarrollosostenible de todos los países. La producción descentralizada de energía, fundamentada con acierto por losdefensores del denominado camino energético suave o el camino del Sol, permite la transformación de energíacon tecnologías preferentemente no contaminantes en el lugar de consumo. Con esto se reducirían de modoconsiderable las pérdidas energéticas ocasionadas por los procesos de transmisión y distribución. La celdacombustible constituye la tecnología de mayor potencial para revolucionar el panorama energético en este siglo.Como transformador electroquímico, la conversión energética máxima posible se define por la energía libre dereacción en un régimen de temperatura relativamente bajo. En este trabajo se realiza un análisis de los diferentestipos de celdas combustibles y se caracteriza el estado actual de esta tecnología. Además, se analiza el usodel hidrógeno solar en celdas combustibles.  The solution to the actual energy problems and to the progressive damage of the environment is closely relatedwith the election of alternative energy systems that it be able to guarantee the sustainable development of all thecountries. The decentralized energy production, based with success by the defenders of the one denominatedsoft energy way or Sun way, allows the energy transformation with technologies preferably not pollutants in theplace of  consumption. It would decrease in a considerable way the energy losses caused by the transmissionprocesses and distribution. The fuel cell constitutes the technology of more potential to revolutionize the energypanorama in this century. As electrochemical transformer, the possible maximum energy conversion is definedfor the free energy of reaction in a relatively

Limitaciones para el desarrollo de energías renovables en Argentina

OpenAIRE

Marina Yesica Recalde; Daniel Hugo Bouille; Leónidas Osvaldo Girardin

2015-01-01

En las últimas décadas las energías renovables han cobrado impulso a nivel mundial con un significativo impacto sobre el desarrollo sustentable de las naciones. Si bien diferentes trabajos analizan la eficiencia de políticas e instrumentos para la promoción de dichas fuentes, la mayoría de las veces se deja de lado el análisis de cómo el contexto en el cual las políticas son implementadas determina su performance. En este trabajo se analiza el desarrollo de las energías renovables en el merca...

Productividad y eficiencia energética en el proceso de molienda del mineral laterítico

Directory of Open Access Journals (Sweden)

Olga Angulo-Leblanch

2000-03-01

Full Text Available En el trabajo se realiza un análisis energético del proceso de molienda seca del mineral laterítico, considerado como el proceso de mayor consumo de energía eléctrica entre los procesos beneficiadores que se emplean en las plantas niquelíferas, ubicadas al norte de la provincia de Holguín. Son analizadas las particularidades energéticas que exhibe este proceso cuando las máquinas trabajan normalmente con la presencia de mineral y cuando se producen ausencias ocasionales de éste en el sistema, lo que trae como consecuencia el incremento notable de las potencias demandadas por los molinos y por los ventiladores de recirculación . Se analiza además, la influencia del grado de llenado con bolas del molino, sobre la productividad y la estrecha relación de esta última con la eficiencia energética del proceso. El método fundamental de análisis empleado, se basa en la obtención experimental y en las condiciones concretas de explotación, de las características energéticas de las unidades de molienda y de sus agregados, como vía directa para descubrir las reservas de energía del sistema y conocer hasta qué punto es posible mejorar su eficiencia influyendo sobre la productividad. El trabajo revela que, cuando las unidades de molienda son operadas con valores de productividades que oscilan entre un 50 y un 60% de la nominal, si son adoptadas las medidas pertinentes para lograr el aumento de la productividad, entonces esto puede reportar hasta un 55% de mejoramiento de la eficiencia energética del proceso.

Monitoreo energético y estrategias de RETROFIT para viviendas sociales en clima frío.

Directory of Open Access Journals (Sweden)

Micaela Andersen

2017-12-01

Full Text Available El presente trabajo aborda la aplicación de tecnologías y pautas para el reciclado masivo de viviendas urbanas representativas. Se evalúa aquí el comportamiento energético actual en una vivienda social “tipo” con un alto nivel de replicabilidad. Para ello, se cuantifica el potencial ahorro energético al aplicar diversas estrategias de mejoramiento de la envolvente edilicia que permitan arribar a valores admisibles de pérdidas térmicas, de acuerdo con la normativa argentina. Se describe la tecnología, el comportamiento térmico y energético de una vivienda perteneciente al barrio “645 Viviendas” (desarrollado por El Instituto de Planificación y Promoción de la Vivienda, ubicada en la ciudad de San Carlos de Bariloche, en la zona bioambiental IV, muy fría. Este barrio presenta una emergencia energética de gran magnitud, ya que no se encuentra conectado a la red de gas natural. Posteriormente, se examinan los resultados de la auditoria energética de 2016 y se muestra la simulación térmica realizada en Ecotect Analysis 2011, incorporando las condiciones reales de uso auditadas. Ajustado el modelo, se analizan 24 estrategias de mejoramiento de la envolvente térmica, posibilitando la identificación de las estrategias de mayor impacto en la reducción de la demanda energética.

Certificación energética de edificios en España y sus implicaciones económicas

Directory of Open Access Journals (Sweden)

Ruá, M. J.

2012-09-01

Full Text Available Under the European Energy Performance of Buildings Directive, the Member States must develop methods to certify energy efficiency of buildings. Calener-VYP v1.0 is the only Spanish official tool to certify a high energy efficiency performance of residential buildings, through the general option. It has two indicators implemented, CO₂ emissions and primary energy consumption. However, in the process of energy rating a building, only the CO₂ emissions indicator is considered. The economic consequences of this are studied, by means of simulating real properties with different construction assemblies and building services in the twelve Spanish climatic zones and calculating their costs. The results show that having a better energy rate in Calener VYP does not necessarily entail a lower consumption cost. Therefore, it is necessary to include the annual primary energy consumption indicator, because its absence involves that costs cannot be used as an argument when promoting energy efficiency among users.

Bajo la Directiva Europea sobre eficiencia energética de los edificios, los Estados Miembros deben desarrollar procedimientos para certificar energéticamente los edificios. Calener-VYP v1.0 es la única herramienta oficial española para certificar una elevada aptitud en eficiencia energética de edificios residenciales, por el método general. Tiene dos indicadores implementados, emisiones de CO₂ y consumo de energía primaria. Sin embargo, en el proceso de otorgar la calificación energética, solamente se consideran las emisiones de CO₂. Las implicaciones económicas de esto se estudian simulando viviendas con diferentes características constructivas e instalaciones en las doce zonas climáticas españolas y calculando sus costes. Los resultados muestran que una mejor calificación energética en Calener-VYP no implica necesariamente un menor coste de consumo energético. Por tanto, es necesario

Avaliação energética de um sistema integrado de abastecimento de água

Directory of Open Access Journals (Sweden)

Ana Luiza Rezende Guanais

2017-07-01

Full Text Available RESUMO Os encargos energéticos decorrentes do Sistema Integrado de Abastecimento de Água de Feira de Santana (SIAA-FSA foram analisados utilizando o método de avaliação do ciclo de vida. Foram identificadas, na cadeia de abastecimento de água, as etapas do sistema com maiores encargos energéticos, e propostos cenários de melhoria. Cadeias de produção dos insumos químicos, transporte dos insumos, energia elétrica e substituição dos tubos na rede para a manutenção do SIAA-FSA foram consideradas. A demanda energética acumulada do SIAA-FSA foi de 3,51 kWh.m-3 de água consumida. As etapas de captação e distribuição de água apresentaram os maiores consumos energéticos, e a eletricidade do bombeamento representou 86% da demanda energética acumulada. Os cenários propostos para o SIAA-FSA apresentaram melhorias significativas em relação ao cenário atual, com usos mais racionais de insumos químicos, eletricidade e água.

El papel de la energía renovable en la competitividad un bosquejo de México

Directory of Open Access Journals (Sweden)

Laura Leticia Laurent Martínez

2016-03-01

Full Text Available La relación entre la energía y el desarrollo parece incuestionable. Entre más energía y más requerimientos tecnológicos haya que poner en juego para producirla, más avanzados se consideran los países. Sin embargo, los criterios están cambiando aceleradamente, aunque sin las repercusiones esperadas por los defensores de la competitividad. En este artículo se presenta un panorama global del bienestar de los seres vivos mediante la sustitución de las energías provenientes de los fósiles y de la fisión nuclear por energía renovable (er. Se prosigue con una serie de argumentaciones sobre el papel que desempeñan las energías renovables en la competitividad sustentable en relación con la competitividad efímera. Finalizamos con una breve descripción de la posición de México en el renglón de la er, la cual ofrece un marco para una reflexión crítica de las restricciones de la sustentabilidad en México

Photosystem II repair and plant immunity: Lessons learned from Arabidopsis mutant lacking the THYLAKOID LUMEN PROTEIN 18.3

Directory of Open Access Journals (Sweden)

Sari eJärvi

2016-03-01

Full Text Available Chloroplasts play an important role in the cellular sensing of abiotic and biotic stress. Signals originating from photosynthetic light reactions, in the form of redox and pH changes, accumulation of reactive oxygen and electrophile species or stromal metabolites are of key importance in chloroplast retrograde signaling. These signals initiate plant acclimation responses to both abiotic and biotic stresses. To reveal the molecular responses activated by rapid fluctuations in growth light intensity, gene expression analysis was performed with Arabidopsis thaliana wild type and the tlp18.3 mutant plants, the latter showing a stunted growth phenotype under fluctuating light conditions (Biochem. J, 406, 415-425. Expression pattern of genes encoding components of the photosynthetic electron transfer chain did not differ between fluctuating and constant light conditions, neither in wild type nor in tlp18.3 plants, and the composition of the thylakoid membrane protein complexes likewise remained unchanged. Nevertheless, the fluctuating light conditions repressed in wild-type plants a broad spectrum of genes involved in immune responses, which likely resulted from shade-avoidance responses and their intermixing with hormonal signaling. On the contrary, in the tlp18.3 mutant plants there was an imperfect repression of defense-related transcripts upon growth under fluctuating light, possibly by signals originating from minor malfunction of the photosystem II (PSII repair cycle, which directly or indirectly modulated the transcript abundances of genes related to light perception via phytochromes. Consequently, a strong allocation of resources to defense reactions in the tlp18.3 mutant plants presumably results in the stunted growth phenotype under fluctuating light.

Comparative study of the active cadmium efflux systems operating at the plasma membrane and tonoplast of cucumber root cells.

Science.gov (United States)

Migocka, Magdalena; Papierniak, Anna; Kosatka, Ewelina; Klobus, Grazyna

2011-10-01

The strategies developed by plants to avoid the toxicity of cadmium (Cd) and other heavy metals involve active sequestration of metals into the apoplast and vacuoles. The protein systems excluding heavy metals from the cell cytosol localize to the plasma membrane and tonoplast and are energized either by ATP or by the electrochemical gradient generated by H(+)-ATPase or by V-ATPase and pyrophosphatase (PPase), respectively. In this work, a comparative study on the contribution of both the plasma membrane and tonoplast in the active detoxification of plant cells after treatment with Cd was performed. The studies using plants treated and untreated with Cd reveal that both, H(+)-coupled and MgATP-driven efflux of Cd across plasma membranes and tonoplast is markedly stimulated in the presence of Cd in the environment. Previous studies on plasma-membrane localized H(+)-coupled Cd efflux together with the present data demonstrating tonoplast H(+)/Cd(2+) antiport activity suggest that H(+)-coupled secondary transport of Cd displays a lower affinity for Cd when compared with Cd primary pumps driven by MgATP. In addition, it is shown that MgATP-energized Cd efflux across both membranes is significantly enhanced by cysteine, dithiothreitol, and glutathione. These results suggest that Cd is excluded from the cytosol through an energy-dependent system as a free ion as well as a complexed form. Although both membranes contribute in the active exclusion of ionized and complexed Cd from the cytosol, the overall calculation of Cd accumulation in the everted plasma membranes and vacuolar vesicles suggests that the tonoplast and vacuole have a major function in Cd efflux from the cytosol in the roots of cucumber subjected to Cd stress.

Evaluación energética y validación matemática de un sistema de conversión de energía por rozamiento

OpenAIRE

Barona Díaz, Santiago Xavier

2016-01-01

El presente trabajo, consiste en la Evaluación Energética y validación Matemática de un nuevo dispositivo de calentamiento, que aprovecha la alta energía calórica producida por la fricción y el aplastamiento de un anillo cilíndrico de aleación Cu-Sn. En este proceso de transformación mecánico térmica, a temperaturas de trabajo sobre los 800ºC intervienen características tales como el área de la pared conductiva, torque, velocidad de rotación, fuerza axial de compresión, tipo de materiales, qu...

La utilización eficaz del hormigón térmico en rehabilitación energética de edifcios

OpenAIRE

Moraño Rodríguez, Alfonso Javier

2016-01-01

Como sabrá el lector, se ha establecido en España por consecuencia de la Directiva 2012/27/ UE, un Programa de Ayudas para la Rehabilitación Energética de Edificios existentes (Programa PAREER-CRECE) con el fin de incentivar y promover la realización de actuaciones de reforma que favorezcan el ahorro energético, la mejora de la eficiencia energética, el aprovechamiento de las energías renovables y la reducción de emisiones de dióxido de carbono. El Ministerio de Industria, Energía y Turismo, ...

Modelo de cooperación energética entre China y América Latina

OpenAIRE

Hongbo, Sun

2014-01-01

Las relaciones entre China y América Latina han tenido más implicaciones estratégicas en la actual transición de poder político y económico internacional, en particular, sus vínculos energéticos han sido testigos de grandes avances de cooperación entre industrias de petróleo y gas. La cooperación energética de China con América Latina se compone, en una parte nada despreciable, de cambios en curso en energía en el occidente del hemisferio. Las compañías petroleras chinas recurren a diferentes...

Análisis de sistema de conversores fluido-dinámicos de energía renovable para la Patagonia Austral de Argentina

Directory of Open Access Journals (Sweden)

Carlos Victor Manuel Labriola

2014-06-01

Full Text Available El potencial de energía en mares y océanos se puede clasificar de distintas formas, por ejemplo: * La energía de las mareas ó Mareomotriz * La energía de las corrientes marinas * La energía de las olas ó Undimotriz * La energía térmica oceánica (OTEC. De estas formas de energía oceánica, tres son posibles en la zona Atlántica de nuestra Patagonia Austral, la Mareomotriz, la Undimotriz y la de corrientes marinas. La Energía Mareomotriz se da desde Viedma hasta Tierra del Fuego con amplitudes de mareas de 4m hasta 20m, la Energía de las Olas se da en la costa de Chubut y Santa Cruz con potenciales de 10 a 30kW/m lineal de frente de ola y el aprovechamiento de las corrientes marinas se puede dar en lugares puntuales como ser la desembocadura del río Deseado o la de Río Gallegos. Para estas Fuentes de Energía se está realizando un banco de pruebas de modelos conversores de las mismas a Energía Eléctrica, en la Unidad Académica Caleta Olivia (UACO de la Universidad Nacional de la Patagonia Austral (UNPA. Este banco dispondrá de dos canales de ensayos hidrodinámicos uno para energía de las corrientes marinas y otro para las olas. El primero dispondrá de una bomba de circulación con velocidad de fluido variable entre 0 y 4m/s. El banco para olas tendrá un sistema de batido del agua para producir ondas de amplitud y período variable. Además se están dimensionando dos modelos de conversores de energía oceánica. Uno es una turbina, tipo eólica sumergida y el otro modelo es de tubo electromecánico oscilante como conversor energético de las olas.

Diseño metodológico de la evaluación de proyectos energéticos bajo incertidumbre en precios: caso de cogeneración de energía en una empresa en Cali

Directory of Open Access Journals (Sweden)

Carlos Andrés Núñez Viveros

2013-01-01

Full Text Available Los recursos energéticos en la industria recobran mayor relevancia en su competitividad, representando el se- gundo o tercer rubro en el costo. El comportamiento fluctuante de los costos históricos, así como la incertidum- bre de su tendencia futura, acentuada por la inminencia del desmonte del impuesto de contribución en energía eléctrica (20% de la tarifa, conllevan el cuestionamiento de si los proyectos de cogeneración de energía tendrán viabilidad en un futuro cercano. El presente trabajo desarrolla una metodología innovadora para evaluar la via- bilidad de la implementación de proyectos de cogeneración, fundamentada en 3 simuladores que trabajan con información estadística y proyecciones matemáticas, además de realizar un análisis de sensibilidad del proyecto a los comportamientos proyectados de los precios futuros de la energía eléctrica y de los combustibles.

Una solución al problema de la energía y de la contaminación en México

Directory of Open Access Journals (Sweden)

Dieter Klaus

1975-01-01

Full Text Available La crisis energética ha demostrado mundialmente que nuestro concepto de "energía" es insostenible. se necesitan tres unidades caloríficas provenientes del petróleo o el carbón para producir una unidad de energía eléctrica superior. Menos favorable es el aprovechamiento en la conversión del combustible en movimiento de nuestros vehículos. La obtención de energía proveniente del aceite crudo es irreversible.

Integración energética: una incertidumbre regulatoria

Directory of Open Access Journals (Sweden)

María de la Cruz Bayá C.

2006-01-01

Full Text Available Este artículo pretende introducir en la reflexión de los elementos que están insertos hoy por hoy en la agenda de la integración energética, como uno de los baluartes más importantes para la consolidación de los procesos subregionales ya que establece, per se, la base de la nueva configuración de las relaciones interestatales a partir de la relación de oferta y demanda energética. En este sentido, los métodos utilizados en la presente investigación han sido el exegético, comparado, estudio de caso y bibliográfico, lo cual ha permitido concluir que se requiere de la generación de un marco regulatorio comunitario armonizado, vinculado a los principios de supranacionalidad y de sustentabilidad.

Análisis DAFO del sector de la energía eólica en España

Directory of Open Access Journals (Sweden)

López-Vico, Victoria

2009-06-01

Full Text Available a energía eólica se ha convertido en un sector económico y energético clave en la actualidad, tanto en España como en el resto del mundo. Con el objetivo de saber si ésta energía puede responder a las necesidades de demanda energética, siendo una energía sustitutiva a los tradicionales combustibles fósiles, hemos realizado un análisis DAFO, donde se muestran las debilidades, amenazas, fortalezas y oportunidades de este sector en auge.Wind power has become a very important economic and power sector, as much in Spain as in the rest of the world. With the aim of knowing if this energy can respond to the energetic demand, being a substitute energy to traditional fossil fuels, we have realised a SWOT analysis, where we can know the strengths, threats, opportunities and weaknesses of this sector in full expansion.

Transformer inrush current reduction through sequential energization for wind farm applications

Energy Technology Data Exchange (ETDEWEB)

Abdulsalam, S.; Xu, W. [Alberta Univ., Edmonton, AB (Canada)

2008-07-01

Wind power is considered as one of the fastest growing technologies in the power industry. The electrical configuration of a wind farm consists of long spans of medium voltage collector feeders. Each wind generator is connected to the collector circuit/feeder through either a pad mount oil filled, or a nacelle-mounted dry type transformer. All collector feeders connect to a single collector substation where the connection to the high-voltage transmission is established through a step up transformer. With a large number of wind generators per feeder, large inrush current will flow due to simultaneous transformer energization which can cause high voltage sag at the point of common coupling. Wind farms are generally located in unpopulated remote areas where no access to strong network connection is feasible. It is common to have the PCC on a relatively weak location on the sub-transmission/distribution network. In order to meet interconnection standards requirements, the amount of voltage sag due to the energization of a number of transformers needs to be evaluated. This paper presented an effective solution to the mitigation of inrush currents and associated voltage sag for wind farm applications. The paper presented a diagram of a typical configuration of a wind farm electrical distribution system and also described the analytical methodologies for the evaluation of inrush current level together with simulation results. A simplified analysis and sizing criteria for the associated neutral resistor size was presented. It was concluded that the scheme could significantly reduce inrush current level when a large number of transformers are simultaneously energized. The presented application eliminates the need to sectionalize feeders, thereby simplifying them for the energization process. 6 refs., 5 figs.

La Reforma Energética: a 20 años del TLCAN

OpenAIRE

Vargas, Rosío

2015-01-01

La visita del presidente estadounidense Barack Obama a México, en mayo de 2013, fue la ocasión para buscar el acceso al petróleo y gas mexicano, amparado en el argumento de los 20 años del TLCAN, bajo "la necesidad" de su relanzamiento. Cabilderos nacionales y extranjeros se dieron a la tarea de elaborar la estrategia para la apertura total del sector energético mexicano bajo la propuesta de la Reforma Energética mexicana, aprobada el 20 de diciembre de 2013. En las modificaciones constitucio...

Sustentabilidad empresarial, seguridad energética y ética ambiental en Chile

OpenAIRE

Suárez,Andrés

2013-01-01

El artículo explora la relación entre sustentabilidad empresarial -asociada tanto a la rentabilidad financiera como a las relaciones con colectivos locales- y el medioambiente, en el contexto de una economía internacionalizada como la chilena. Asimismo, analiza conflictos recientes originados en Chile para la provisión de energía y las dificultades en la definición de una matriz energética, y, finalmente, la influencia de la ética ecológica para la preservación de los ecosistemas de alta biod...

Lifetime cost effectiveness of a through-school nutrition and physical programme: Project Energize.

Science.gov (United States)

Rush, Elaine; Obolonkin, Victor; McLennan, Stephanie; Graham, David; Harris, James D; Mernagh, Paul; Weston, Adéle R

2014-01-01

Project Energize, a multicomponent through-school physical activity and nutrition programme, is delivered to all primary school children in the Waikato region. The programme aim is to improve the overall health and reduce the rate of weight gain of all Waikato primary school children. An existing economic model was used to extrapolate the programme effects, initial costs, lifetime health treatment cost structures, quality-adjusted-life-years gained and increased life expectancy to the general and Māori child population of New Zealand. In March 2011, a sample of 2474 younger (7.58 ± 0.57 years, mean ± SD) and 2330 older (10.30 ± 0.51 years) children (36% Māori) attending Energize schools had body mass index measured and compared using mixed effect modelling with unEnergized comparison children from 2004 and 2006 from the same region. In 2011 the median body mass index reduction compared with the comparison younger children was -0.504 (90% CI -0.435 to -0.663) kg/m(2) and in the older children -0.551 (-0.456 to -0.789) kg/m(2). In 2010 there were 42,067 children attending Energize schools and in the same year NZ$1,891,175 was spent to deliver the programme; a cost of $44.96/child/year. Compared to the comparison children the increment in cost/quality-adjusted-life-year gained was $30,438 for the younger and $24,690 for the older children, and lower for Māori (younger $28,241, older $22,151) and for the middle socioeconomic status schools ($23,211, $17,891). Project Energize would improve quality and length of life and when compared with other obesity prevention programmes previously assessed with this model, it would be relatively cost-effective from the health treatment payer's perspective.

Electrolyte control of photosynthetic electron transport in cyanobacteria

International Nuclear Information System (INIS)

Papageorgiou, G.C.

1986-01-01

Ion-permeable cells (permeaplasts) of the cyanobacterium Anacystis nidulans were prepared enzymatically and were characterized with respect to several structural and functional indices. The permeaplasts contain intact, ion-impermeable thylakoids and are photosynthetically active. The authors discuss how, employing these cells, they investigated the effects of cations, acting either on the outer, or on the inner thylakoid membrane surface, on photoinduced electron exchanges with anionic donors (Cyt c-550, plastocyanin, innersurface), or anionic acceptors (FeCN 3- ; outer surface). Cations accelerate such exchanges by accumulating near the solution-membrane interfaces and screening the negative surface charge of membranes. Electrostatic screening, however, is not the only contributing factor, and other electrolyte-linked influences must be invoked in order to interpret the experimental observations

The 1.7 Å resolution structure of At2g44920, a pentapeptide-repeat protein in the thylakoid lumen of Arabidopsis thaliana

International Nuclear Information System (INIS)

Ni, Shuisong; McGookey, Michael E.; Tinch, Stuart L.; Jones, Alisha N.; Jayaraman, Seetharaman; Tong, Liang; Kennedy, Michael A.

2011-01-01

The crystal structure of At2g44920, a pentapeptide repeat protein (PRP) from Arabidopsis thaliana, has been determined at 1.7 Å resolution. The structure represents the first PRP protein whose subcellular localization has been experimentally confirmed to be the thylakoid lumen of a plant species. At2g44920 belongs to a diverse family (Pfam PF00805) of pentapeptide-repeat proteins (PRPs) that are present in all known organisms except yeast. PRPs contain at least eight tandem-repeating sequences of five amino acids with an approximate consensus sequence (STAV)(D/N)(L/F)(S/T/R)(X). Recent crystal structures show that PRPs adopt a highly regular four-sided right-handed β-helical structure consisting mainly of type II and type IV β-turns, sometimes referred to as a repeated five-residue (or Rfr) fold. Among sequenced genomes, PRP genes are most abundant in cyanobacteria, leading to speculation that PRPs play an important role in the unique lifestyle of photosynthetic cyanobacteria. Despite the recent structural characterization of several cyanobacterial PRPs, most of their functions remain unknown. Plants, whose chloroplasts are of cyanobacterial origin, have only four PRP genes in their genomes. At2g44920 is one of three PRPs located in the thylakoid lumen. Here, the crystal structure of a double methionine mutant of residues 81–224 of At2g44920, the naturally processed fragment of one of its full-length isoforms, is reported at 1.7 Å resolution. The structure of At2g44920 consists of the characteristic Rfr fold with five uninterrupted coils made up of 25 pentapeptide repeats and α-helical elements capping both termini. A disulfide bridge links the two α-helices with a conserved loop between the helical elements at its C-terminus. This structure represents the first structure of a PRP protein whose subcellular location has been experimentally confirmed to be the thylakoid lumen in a plant species

Molecular electronics of a single photosystem I reaction center: Studies with scanning tunneling microscopy and spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Lee, I.; Lee, J.W.; Warmack, R.J.; Allison, D.P.; Greenbaum, E. [Oak Ridge National Lab., TN (United States)

1995-03-14

Thylakoids and photosystem I (PSI) reaction centers were imaged by scanning tunneling microscopy. The thylakoids were isolated from spinach chloroplasts, and PSI reaction centers were extracted from thylakoid membranes. Because thylakoids are relatively thick nonconductors, they were sputter-coated with Pd/Au before imaging. PSI photosynthetic centers and chemically platinized PSI were investigated without sputter-coating. They were mounted on flat gold substrates that had been treated with mercaptoacetic acid to help bind the proteins. With tunneling spectroscopy, the PSI centers displayed a semiconductor-like response with a band gap of 1.8 eV. Lightly platinized (platinized for 1 hr) centers displayed diode-like conduction that resulted in dramatic contrast changes between images taken with opposite bias voltages. The electronic properties of this system were stable under long-term storage. 42 refs., 7 figs.

Evolutionary conservation of dual Sec translocases in the cyanelles of Cyanophora paradoxa

Directory of Open Access Journals (Sweden)

Löffelhardt Wolfgang

2008-11-01

Full Text Available Abstract Background Cyanelles, the peptidoglycan-armored plastids of glaucocystophytes, occupy a unique bridge position in between free-living cyanobacteria and chloroplasts. In some respects they side with cyanobacteria whereas other features are clearly shared with chloroplasts. The Sec translocase, an example for "conservative sorting" in the course of evolution, is found in the plasma membrane of all prokaryotes, in the thylakoid membrane of chloroplasts and in both these membrane types of cyanobacteria. Results In this paper we present evidence for a dual location of the Sec translocon in the thylakoid as well as inner envelope membranes of the cyanelles from Cyanophora paradoxa, i. e. conservative sorting sensu stricto. The prerequisite was the generation of specific antisera directed against cyanelle SecY that allowed immunodetection of the protein on SDS gels from both membrane types separated by sucrose density gradient floatation centrifugation. Immunoblotting of blue-native gels yielded positive but differential results for both the thylakoid and envelope Sec complexes, respectively. In addition, heterologous antisera directed against components of the Toc/Tic translocons and binding of a labeled precursor protein were used to discriminate between inner and outer envelope membranes. Conclusion The envelope translocase can be envisaged as a prokaryotic feature missing in higher plant chloroplasts but retained in cyanelles, likely for protein transport to the periplasm. Candidate passengers are cytochrome c6 and enzymes of peptidoglycan metabolism. The minimal set of subunits of the Toc/Tic translocase of a primitive plastid is proposed.

Design and Implementation of Energized Fracture Treatment in Tight Gas Sands

Energy Technology Data Exchange (ETDEWEB)

Mukul Sharma; Kyle Friehauf

2009-12-31

Hydraulic fracturing is essential for producing gas and oil at an economic rate from low permeability sands. Most fracturing treatments use water and polymers with a gelling agent as a fracturing fluid. The water is held in the small pore spaces by capillary pressure and is not recovered when drawdown pressures are low. The un-recovered water leaves a water saturated zone around the fracture face that stops the flow of gas into the fracture. This is a particularly acute problem in low permeability formations where capillary pressures are high. Depletion (lower reservoir pressures) causes a limitation on the drawdown pressure that can be applied. A hydraulic fracturing process can be energized by the addition of a compressible, sometimes soluble, gas phase into the treatment fluid. When the well is produced, the energized fluid expands and gas comes out of solution. Energizing the fluid creates high gas saturation in the invaded zone, thereby facilitating gas flowback. A new compositional hydraulic fracturing model has been created (EFRAC). This is the first model to include changes in composition, temperature, and phase behavior of the fluid inside the fracture. An equation of state is used to evaluate the phase behavior of the fluid. These compositional effects are coupled with the fluid rheology, proppant transport, and mechanics of fracture growth to create a general model for fracture creation when energized fluids are used. In addition to the fracture propagation model, we have also introduced another new model for hydraulically fractured well productivity. This is the first and only model that takes into account both finite fracture conductivity and damage in the invaded zone in a simple analytical way. EFRAC was successfully used to simulate several fracture treatments in a gas field in South Texas. Based on production estimates, energized fluids may be required when drawdown pressures are smaller than the capillary forces in the formation. For this field

The microalga Chlamydomonas reinhardtii CW-15 as a solar cell for hydrogen peroxide photoproduction. Comparison between free and immobilized cells and thylakoids for energy conversion efficiency

Energy Technology Data Exchange (ETDEWEB)

Scholz, W.; Galvan, F.; Rosa, F.F. de la [Instituto de Bioquimica Vegetal y Fotosintesis, Universidad de Sevilla y CSIC, Sevilla (Spain)

1995-11-28

Immobilized cells and thylakoid vesicles of the microalga Chlamydomonas reinhardtii CW-15 have been developed as a solar cell because of their capabilities of producing hydrogen peroxide. This compound is an efficient and clean fuel used for rocket propulsion, motors and for heating. Hydrogen peroxide is produced by the photosystem in a catalyst cycle in which a redox mediator (methyl viologen) is reduced by electrons obtained from water by the photosynthetic apparatus of the microalga and it is re-oxidized by the oxygen dissolved in the solution. The photoproduction has been investigated using a discontinuous system with whole cells, or thylakoid vesicles, free or immobilized on alginate. The stimulation by azide as an inhibitor of catalase has also been analyzed. Under determined optimum conditions, the photoproduction by Ca-alginate entrapped cells, with a rate of 33 {mu}mol H{sub 2}O{sub 2}/mg Chl.h, was maintained for several hours with an energy conversion efficiency of 0.25%

The mechanism of uncoupling by picrate in Escherichia coli K-12 membrane systems.

Science.gov (United States)

Michels, M; Bakker, E P

1981-06-01

The mechanism of action of the uncoupler picrate on intact cells and everted membrane vesicles of Escherichia coli K-12 was investigated. Like in mitochondria [Hanstein, W. G. and Hatefi, Y. (1974) Proc. Natl Acad. Sci. USA, 71, 288-292], it was observed that picrate uncoupled energy-linked functions only in everted, but not in intact membrane systems. In the vesicles picrate also decreased the magnitude of the transmembrane proton-motive force at concentrations similar to those at which it caused uncoupling. Experiments with 14C-labelled picrate showed that this compound bound both to deenergized intact cells and everted vesicles. However, upon energization of the membrane, picrate was extruded from the intact cell and taken up to a larger extent by the vesicles. These energy-dependent changes in picrate uptake correlated with the magnitude of the transmembrane electrical potential, delta psi. It is therefore proposed that picrate is a permeant uncoupler, that delta psi is the driving force for picrate movement across biological membranes, and that the uncoupling activity of picrate in everted membrane systems is due to its protonophoric action.

Desarrollo e implantación de energías renovables: situación actual y tendencias

OpenAIRE

Picó Heras, Sergio

2002-01-01

En esta tesina se tratarán las posibilidades que ofrecen las energías renovables com base de una planificicación energética. El tema se enfocará tanto desde puntos de vista económicos, ambientales, técnicos, políticos, etc

The short-term response of Arabidopsis thaliana (C3) and Zea mays (C4) chloroplasts to red and far red light.

Science.gov (United States)

Zienkiewicz, Maksymilian; Drożak, Anna; Wasilewska, Wioleta; Bacławska, Ilona; Przedpełska-Wąsowicz, Ewa; Romanowska, Elżbieta

2015-12-01

Light quality has various effects on photochemistry and protein phosphorylation in Zea mays and Arabidopsis thaliana thylakoids due to different degrees of light penetration across leaves and redox status in chloroplasts. The effect of the spectral quality of light (red, R and far red, FR) on the function of thylakoid proteins in Zea mays and Arabidopsis thaliana was investigated. It was concluded that red light stimulates PSII activity in A. thaliana thylakoids and in maize bundle sheath (BS) thylakoids, but not in mesophyll (M) thylakoids. The light quality did not change PSI activity in M thylakoids of maize. FR used after a white light period increased PSI activity significantly in maize BS and only slightly in A. thaliana thylakoids. As shown by blue native (BN)-PAGE followed by SDS-PAGE, proteins were differently phosphorylated in the thylakoids, indicating their different functions. FR light increased dephosphorylation of LHCII proteins in A. thaliana thylakoids, whereas in maize, dephosphorylation did not occur at all. The rate of phosphorylation was higher in maize BS than in M thylakoids. D1 protein phosphorylation increased in maize and decreased in A. thaliana upon irradiation with both R and growth light (white light, W). Light variations did not change the level of proteins in thylakoids. Our data strongly suggest that response to light quality is a species-dependent phenomenon. We concluded that the maize chloroplasts were differently stimulated, probably due to different degrees of light penetration across the leaf and thereby the redox status in the chloroplasts. These acclimation changes induced by light quality are important in the regulation of chloroplast membrane flexibility and thus its function.

La elasticidad de la demanda por electricidad y la política energética

Directory of Open Access Journals (Sweden)

Alexander Galetovic

2010-01-01

Full Text Available En el análisis y la práctica de la política energética se suele suponer que la elasticidad de la demanda por energía eléctrica es irrelevante. Este trabajo muestra que durante episodios de escasez de energía una “pequeña” elasticidad basta para generar caídas “grandes” de la probabilidad de déficit y del costo del abastecimiento eléctrico. Esto se debe a que en la vecindad de la capacidad del sistema, la oferta de energía de corto plazo es cercana a vertical. Ilustramos nuestro punto cuantitativamente simulando la operación esperada del sistema eléctrico chileno durante los años de ajuste a la crisis causada por los cortes de gas argentinos, el periodo 2006-2010. Mostramos que el aumento de los precios causado por el retraso de las inversiones y los cortes de gas argentino, combinado con una “pequeña” elasticidad de la demanda mensual por energía (0.0548 en valor absoluto eran suficientes para reducir mucho la probabilidad de déficit mensual y retornarla a niveles normales. Más aún, si se soslaya el efecto de los mayores precios en el consumo, el costo marginal se sobreestima en 32% y el costo de operación esperado en 41 por ciento.

Wireless energizing system for an automated implantable sensor

Energy Technology Data Exchange (ETDEWEB)

Swain, Biswaranjan; Nayak, Praveen P.; Kar, Durga P.; Bhuyan, Satyanarayan; Mishra, Laxmi P. [Department of Electronics and Instrumentation Engineering, Siksha ‘O’ Anusandhan University, Bhubaneswar 751030 (India)

2016-07-15

The wireless drive of an automated implantable electronic sensor has been explored for health monitoring applications. The proposed system comprises of an automated biomedical sensing system which is energized through resonant inductive coupling. The implantable sensor unit is able to monitor the body temperature parameter and sends back the corresponding telemetry data wirelessly to the data recoding unit. It has been observed that the wireless power delivery system is capable of energizing the automated biomedical implantable electronic sensor placed over a distance of 3 cm from the power transmitter with an energy transfer efficiency of 26% at the operating resonant frequency of 562 kHz. This proposed method ensures real-time monitoring of different human body temperatures around the clock. The monitored temperature data have been compared with a calibrated temperature measurement system to ascertain the accuracy of the proposed system. The investigated technique can also be useful for monitoring other body parameters such as blood pressure, bladder pressure, and physiological signals of the patient in vivo using various implantable sensors.

Wireless energizing system for an automated implantable sensor

International Nuclear Information System (INIS)

Swain, Biswaranjan; Nayak, Praveen P.; Kar, Durga P.; Bhuyan, Satyanarayan; Mishra, Laxmi P.

2016-01-01

The wireless drive of an automated implantable electronic sensor has been explored for health monitoring applications. The proposed system comprises of an automated biomedical sensing system which is energized through resonant inductive coupling. The implantable sensor unit is able to monitor the body temperature parameter and sends back the corresponding telemetry data wirelessly to the data recoding unit. It has been observed that the wireless power delivery system is capable of energizing the automated biomedical implantable electronic sensor placed over a distance of 3 cm from the power transmitter with an energy transfer efficiency of 26% at the operating resonant frequency of 562 kHz. This proposed method ensures real-time monitoring of different human body temperatures around the clock. The monitored temperature data have been compared with a calibrated temperature measurement system to ascertain the accuracy of the proposed system. The investigated technique can also be useful for monitoring other body parameters such as blood pressure, bladder pressure, and physiological signals of the patient in vivo using various implantable sensors.

Wireless energizing system for an automated implantable sensor.

Science.gov (United States)

Swain, Biswaranjan; Nayak, Praveen P; Kar, Durga P; Bhuyan, Satyanarayan; Mishra, Laxmi P

2016-07-01

The wireless drive of an automated implantable electronic sensor has been explored for health monitoring applications. The proposed system comprises of an automated biomedical sensing system which is energized through resonant inductive coupling. The implantable sensor unit is able to monitor the body temperature parameter and sends back the corresponding telemetry data wirelessly to the data recoding unit. It has been observed that the wireless power delivery system is capable of energizing the automated biomedical implantable electronic sensor placed over a distance of 3 cm from the power transmitter with an energy transfer efficiency of 26% at the operating resonant frequency of 562 kHz. This proposed method ensures real-time monitoring of different human body temperatures around the clock. The monitored temperature data have been compared with a calibrated temperature measurement system to ascertain the accuracy of the proposed system. The investigated technique can also be useful for monitoring other body parameters such as blood pressure, bladder pressure, and physiological signals of the patient in vivo using various implantable sensors.

Membrane composition and physiological activity of plastids from an oenothera plastome mutator-induced chloroplast mutant.

Science.gov (United States)

Johnson, E M; Sears, B B

1990-01-01

Plastids were isolated from a plastome mutator-induced mutant (pm7) of Oenothera hookeri and were analyzed for various physiological and biochemical attributes. No photosynthetic electron transport activity was detected in the mutant plastids. This is consistent with previous ultrastructural analysis showing the absence of thylakoid membranes in the pm7 plastids and with the observation of aberrant processing and accumulation of chloroplast proteins in the mutant. In comparison to wild type, the mutant tissue lacks chlorophyll, and has significant differences in levels of four fatty acids. The analyses did not reveal any differences in carotenoid levels nor in the synthesis of several chloroplast lipids. The consequences of the altered composition of the chloroplast membrane are discussed in terms of their relation to the aberrant protein processing of the pm7 plastids. The pigment, fatty acid, and lipid measurements were also performed on two distinct nuclear genotypes (A/A and A/C) which differ in their compatibility with the plastid genome (type I) contained in these lines. In these cases, only chlorophyll concentrations differed significantly.

Differential Mobility of Pigment-Protein Complexes in Granal and Agranal Thylakoid Membranes of C-3 and C-4 Plants

Czech Academy of Sciences Publication Activity Database

Kirchhoff, H.; Sharpe, R.M.; Herbstová, Miroslava; Yarbrough, R.; Edwards, G.E.

2013-01-01

Roč. 161, č. 1 (2013), s. 497-507 ISSN 0032-0889 Institutional support: RVO:60077344 Keywords : Photosystem-II * Photosynthetic membranes * Electron tomography Subject RIV: ED - Physiology Impact factor: 7.394, year: 2013

Hybrid bio-photo-electro-chemical cells for solar water splitting.

Science.gov (United States)

Pinhassi, Roy I; Kallmann, Dan; Saper, Gadiel; Dotan, Hen; Linkov, Artyom; Kay, Asaf; Liveanu, Varda; Schuster, Gadi; Adir, Noam; Rothschild, Avner

2016-08-23

Photoelectrochemical water splitting uses solar power to decompose water to hydrogen and oxygen. Here we show how the photocatalytic activity of thylakoid membranes leads to overall water splitting in a bio-photo-electro-chemical (BPEC) cell via a simple process. Thylakoids extracted from spinach are introduced into a BPEC cell containing buffer solution with ferricyanide. Upon solar-simulated illumination, water oxidation takes place and electrons are shuttled by the ferri/ferrocyanide redox couple from the thylakoids to a transparent electrode serving as the anode, yielding a photocurrent density of 0.5 mA cm(-2). Hydrogen evolution occurs at the cathode at a bias as low as 0.8 V. A tandem cell comprising the BPEC cell and a Si photovoltaic module achieves overall water splitting with solar to hydrogen efficiency of 0.3%. These results demonstrate the promise of combining natural photosynthetic membranes and man-made photovoltaic cells in order to convert solar power into hydrogen fuel.

Análisis de alternativas tecnológicas y energéticas para el sistema metroplús bajo una evaluación integrada energía, ambiente, economía

OpenAIRE

Alzate, Juan M; Builes, Luis A; Rave, Claudia C.; Smith, Ricardo A.; Cadena, Ángela I.

2008-01-01

Con un modelo de optimización multi­periodo, basado en programación lineal, y de tipo integrado Energía­Ambiente­Economía (MARKAL­Estándar), se estimaron impactos económicos, energéticos y ambientales de cinco alternativas tecnológicas para la flota de buses que atenderá la demanda de movilidad del sistema de transporte masivo de pasajeros, de mediana capacidad, del Área Metropolitana del Valle de Aburrá (Medellín – Colombia) ­Sistema Metroplús­. Las alternativa...

Substrate modulation of fatty acid effects on energization and respiration of kidney proximal tubules during hypoxia/reoxygenation.

Directory of Open Access Journals (Sweden)

Anja Bienholz

Full Text Available Kidney proximal tubules subjected to hypoxia/reoxygenation develop a nonesterified fatty acid-induced energetic deficit characterized by persistent partial mitochondrial deenergization that can be prevented and reversed by citric acid cycle substrates. To further assess the role of competition between fatty acids and substrates on inner membrane substrate carriers in the deenergization and the contribution to deenergization of fatty acid effects on respiratory function, digitonin-permeabilized rabbit and mouse tubules were studied using either addition of exogenous oleate after control normoxic incubation or increases of endogenous fatty acids produced by hypoxia/reoxygenation. The results demonstrated major effects of matrix oxaloacetate accumulation on succinate-supported energization and respiration and their modification by fatty acids. Improvements of energization in the presence of fatty acids by glutamate were shown to result predominantly from lowering matrix oxaloacetate rather than from amelioration of transmembrane cycling of fatty acids and uncoupling. Mouse tubules had 2.5 fold higher rates of succinate utilization, which resulted in stronger effects of oxaloacetate accumulation than rabbit tubules. Hypoxia/reoxygenation induced respiratory inhibition that was more severe for complex I-dependent substrates. Fatty acids themselves did not acutely contribute to this respiratory inhibition, but lowering them during 60 min. reoxygenation to allow recovery of ATP during that period alleviated it. These data clarify the basis for the nonesterified fatty acid-induced mitochondrial energetic deficit in kidney proximal tubules that impairs structural and functional recovery and provide insight into interactions that need to be considered in the design of substrate-based interventions to improve mitochondrial function.

Avaliação do desempenho energético de um grande edifício de serviços existente

OpenAIRE

Garrido, Diogo Emanuel da Silva

2013-01-01

Nesta dissertação pretende-se caracterizar o desempenho energético de um grande edifício de serviços existente, da tipologia ensino, avaliar e identificar potenciais medidas que melhorem aquele desempenho, permitindo, em complemento, determinar a sua classificação energética no âmbito da legislação vigente. A pertinência do estudo prende-se com a avaliação do desempenho energético dos edifícios e com o estudo de medidas de melhoria que permitam incrementar a eficiência energéti...

Self-organizing amyloid in bacteria

DEFF Research Database (Denmark)

Otzen, D. E.; Vad, B. S.; Dueholm, M. S.

2017-01-01

Real biological membranes are complex multi-component systems which are not easily subjected to systematic investigations, although e.g. the dynamics of light-induced structural reorganizations of thylakoid membranes in chloroplast organelles have been studied using time-resolved small-angle neut...

Reference: 483 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available ent and protein content of the thylakoid membranes were otherwise almost unchanged. However, there was a maj...or change in the macroorganization of PSII within these membranes; electron micro...ing complex CP24 affects the structure and function of the grana membranes of higher plant chloroplasts. 11

Las energías renovables como oportunidad y desafío para el desarrollo territorial (Valle de Lerma, Salta – Argentina

Directory of Open Access Journals (Sweden)

Silvina Belmonte

2014-03-01

Full Text Available La evaluación de Energías Renovables se plantea en un contexto de Ordenamiento Territorial del Valle de Lerma (Salta como estrategia para el desarrollo regional y mejora de la calidad de vida y del ambiente. Herramientas de Evaluación Multi-Criterio, aplicaciones de Sistemas de Información Geográfica y técnicas participativas de consulta constituyen el sustento metodológico del trabajo. Los resultados se focalizan en tres puntos: diagnóstico territorial, evaluación del recurso energético y alternativas tecnológicas, y propuestas para la planificación y gestión. En el diagnóstico, las energías renovables fueron identificadas como opciones viables particularmente en cuestiones productivas y de acceso a servicios básicos. La potencialidad de los recursos renovables resultó alta en relación a la radiación solar y recurso hidráulico, moderado para el potencial eólico y de alta diversidad para el tema de biomasa. Entre las medidas de eficiencia y tecnologías evaluadas, surgieron como prioritarias: educación ambiental, planificación energética estratégica y variadas aplicaciones de energía solar (secaderos, invernaderos, arquitectura bioclimática, colectores de agua y cocinas. Entre las orientaciones para el desarrollo de políticas energéticas ‘más’ sustentables se destacaron: coordinación del sector energético con otros sectores y niveles de actuación en el marco de una planificación territorial integral, fortalecimiento de instituciones locales para la gestión energética, y superación de barreras – limitaciones a la transferencia de energías renovables y medidas de eficiencia energética a nivel local. Finalmente, en las conclusiones se plantea la importancia de valorar las energías renovables como oportunidad y desafío para promover procesos de ‘cambio’ en la región, en una concepción más comprometida con el ambiente y la sociedad.

Participación de la energía hidroeléctrica en México para el 2013

OpenAIRE

Loredo González, Jesús Alberto; Mendoza Ramírez, Virginia; Salgado Banda, Karla María; Segovia Salazar, Perla; Vargas de la Rosa, Laura Nohemí; Zamudio Morán, Roberto Abraham; Martínez, Ubaldo

2013-01-01

El estudio de energías alternas es importante pues, en la actualidad, se busca reducir el alto consumo de fuentes energéticas de tipo fósil con el fin de controlar el impacto ambiental ocasionado por la generación de esta. la energía hidroeléctrica es un área de oportunidad que México debe aprovechar, esta depende de la meteorología de cada región así como de los meses con mayor precipitación pluvial. la producción de electricidad por medios hídricos ha presentado una tendencia crecie...

Estudio comparativo de eficiencia energética: Fachada ventilada frente a fachada vegetal

OpenAIRE

Azkorra Larrinaga, Zaloa

2015-01-01

398 p. + anexos En la actualidad se desarrollan multitud de investigaciones relacionadas con la rehabilitación energética lo que la ha convertido en un campo emergente en el sector de la construcción y de la arquitectura.El objetivo general de la tesis es evaluar la aplicabilidad de diferentes sistemas pasivos de rehabilitación de fachadas (fachada ventilada y fachada vegetal) y analizar los beneficios de la incorporación de dichos sistemas en el ahorro energético de edificios.Para ello, s...

Análisis armónico de compensadores de energía reactiva

OpenAIRE

González Hernández, Jaime

2011-01-01

Desde la implantación de la generación y distribución de la energía eléctrica en corriente alterna, la energía reactiva ha sido un factor clave en el diseño y explotación de los consumos y redes eléctricas. El carácter reactivo (inductivo) que presentan, en general, los consumos y los elementos de las redes eléctricas han hecho aparecer a lo largo del tiempo distintos dispositivos y técnicas que buscan "compensar" ese carácter reactivo.

Membrane Composition and Physiological Activity of Plastids from an Oenothera Plastome Mutator-Induced Chloroplast Mutant 1

Science.gov (United States)

Johnson, Ellen M.; Sears, Barbara B.

1990-01-01

Plastids were isolated from a plastome mutator-induced mutant (pm7) of Oenothera hookeri and were analyzed for various physiological and biochemical attributes. No photosynthetic electron transport activity was detected in the mutant plastids. This is consistent with previous ultrastructural analysis showing the absence of thylakoid membranes in the pm7 plastids and with the observation of aberrant processing and accumulation of chloroplast proteins in the mutant. In comparison to wild type, the mutant tissue lacks chlorophyll, and has significant differences in levels of four fatty acids. The analyses did not reveal any differences in carotenoid levels nor in the synthesis of several chloroplast lipids. The consequences of the altered composition of the chloroplast membrane are discussed in terms of their relation to the aberrant protein processing of the pm7 plastids. The pigment, fatty acid, and lipid measurements were also performed on two distinct nuclear genotypes (A/A and A/C) which differ in their compatibility with the plastid genome (type I) contained in these lines. In these cases, only chlorophyll concentrations differed significantly. PMID:16667256

Investigación e impacto ambiental de los edificios. La energía

Directory of Open Access Journals (Sweden)

Rodríguez Aumente, Pedro A.

2005-08-01

Full Text Available This conference describes the main problems of energy use in face of the depleting of fosil resources, energy supply and emission of atmospheric toxic gases, green house effect gases and ozone depleting gases. The relevance of energy consumption in the environment impact is commented, as well as the key points for the posible evolution of the problem and in the appropriate technology research to cope with them In order to improve the energy and ecological efficiency of buidings. The main characteristics of present day technologies for the introduction of renewable energies in buidings are comented, dealing with their barriers for the widespread use. The most recent research on air conditioning using thermal solar energy with absorption machines is described, with application to Madrid.Se presenta la problemática actual del uso de la energía de cara al agotamiento de las fuentes fósiles, el abastecimiento y la contaminación atmosférica de gases tóxicos, de efecto invernadero y destructores de la capa de ozono. Se comenta la relevancia de la energía en el impacto ambiental de los edificios y se discuten los distintos aspectos que inciden en la posible evolución futura del problema y en la mejor estrategia de investigación tecnológica para tratar de mejorar la eficiencia energética y medioambiental de los edificios, especialmente en España. Se presentan las tecnologías actuales de introducción de las energías renovables en los edificios y se comentan sus más relevantes características, haciendo hincapié en las barreras para su difusión. Se describe la actividad más reciente de investigación en la climatización por energía solar haciendo uso de máquina de absorción, con aplicación a Madrid.

Organización Institucional en el Sector Energético en el Uruguay y participantes en el mismo

Directory of Open Access Journals (Sweden)

José A. Alem Deaces

2014-02-01

Full Text Available La energía , su probable falta o escasez, precio y su importancia en la satisfacción de necesidades mínimas humanas,  en el desarrollo y crecimiento de los países mediante la producción, aunque siempre ha sido un tema en estudio, ha cobrado en la actualidad mayor relieve.Ningún país es pasivo ante ello y adecuan su organización a fin de satisfacer sus necesidades y con ella las de sus poblaciones.Hemos asistido  a un proceso de creación de nuevas personas públicas y privadas que se sumaron a las ya existentes, para participar en el ciclo energético.Este proceso cobró impulso en los tres últimos lustros.El Estado, ha tomado decisiones, sea favoreciendo la apertura del mercado energético, sea buscando viabilizar conexiones internacionales, que han llevado a cambios en el sector institucional referido a la energía.Se ha avanzado a tal punto, que ya podríamos hablar de un “Derecho de la Energía”, lo que será objeto de discusión en su momento, con este trabajo pretendo iniciar el estudio y discusión profundo desde el punto de vista jurídico de un tema, que ha cumplido la mayoría de edad.La determinación de las personas que intervienen el ciclo energético, es un importante primer paso.

Programación por metas Energía alternativa mediante biomasa.

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Guerrero Casas, Flor María

2003-01-01

Full Text Available En este trabajo se presenta un modelo multicriterio de localización de centrales de generación de energía eléctrica mediante biomasa. Los objetivos considerados son: (1 minimizar el coste total de la operación, (2 maximizar la producción de electricidad obtenida, (3 maximizar la distancia entre plantas, (4 maximizar la aceptación social y (5 establecer las plantas o ampliaciones en aquellos lugares donde exista una mayor predisposición por parte de las administraciones locales. Finalmente, se concluye con una aplicación práctica mediante programación por metas ponderadas para la región andaluza, considerando los residuos procedentes del olivar como fuente de energía.

Consideraciones para la adopción de energía nucleoeléctrica a la matriz energética del Ecuador e interconexión a Colombia y Perú

OpenAIRE

Amancha Proaño, Pablo Israel

2014-01-01

El consumo mundial de energía eléctrica ha tenido un considerable crecimiento, con mayor penetración de tecnologías fósiles, aumentando las concentraciones globales de CO2 y CH4, que exceden valores medios de los últimos milenios, lo cual provocará problemas en el clima global. Urge adoptar tecnologías sustentables en diferentes países y sectores. Ecuador, Perú y Colombia, con tasas similares de crecimiento en lo económico y energético, han visto en la hidroenergía su principal fuente de gene...

Expression of the recombinant bacterial outer surface protein A in tobacco chloroplasts leads to thylakoid localization and loss of photosynthesis.

Science.gov (United States)

Hennig, Anna; Bonfig, Katharina; Roitsch, Thomas; Warzecha, Heribert

2007-11-01

Bacterial lipoproteins play crucial roles in host-pathogen interactions and pathogenesis and are important targets for the immune system. A prominent example is the outer surface protein A (OspA) of Borrelia burgdorferi, which has been efficiently used as a vaccine for the prevention of Lyme disease. In a previous study, OspA could be produced in tobacco chloroplasts in a lipidated and immunogenic form. To further explore the potential of chloroplasts for the production of bacterial lipoproteins, the role of the N-terminal leader sequence was investigated. The amount of recombinant OspA could be increased up to ten-fold by the variation of the insertion site in the chloroplast genome. Analysis of OspA mutants revealed that replacement of the invariant cysteine residue as well as deletion of the leader sequence abolishes palmitolyation of OspA. Also, decoration of OspA with an N-terminal eukaryotic lipidation motif does not lead to palmitoylation in chloroplasts. Strikingly, the bacterial signal peptide of OspA efficiently targets the protein to thylakoids, and causes a mutant phenotype. Plants accumulating OspA at 10% total soluble protein could not grow without exogenously supplied sugars and rapidly died after transfer to soil under greenhouse conditions. The plants were found to be strongly affected in photosystem II, as revealed by the analyses of temporal and spatial dynamics of photosynthetic activity by chlorophyll fluorescence imaging. Thus, overexpression of OspA in chloroplasts is limited by its concentration-dependent interference with essential functions of chloroplastic membranes required for primary metabolism.

Hybrid bio-photo-electro-chemical cells for solar water splitting

OpenAIRE

Pinhassi, Roy I.; Kallmann, Dan; Saper, Gadiel; Dotan, Hen; Linkov, Artyom; Kay, Asaf; Liveanu, Varda; Schuster, Gadi; Adir, Noam; Rothschild, Avner

2016-01-01

Photoelectrochemical water splitting uses solar power to decompose water to hydrogen and oxygen. Here we show how the photocatalytic activity of thylakoid membranes leads to overall water splitting in a bio-photo-electro-chemical (BPEC) cell via a simple process. Thylakoids extracted from spinach are introduced into a BPEC cell containing buffer solution with ferricyanide. Upon solar-simulated illumination, water oxidation takes place and electrons are shuttled by the ferri/ferrocyanide redox...

Física y química: 1 Bachillerato. Calor y principio de conservación de la energía

OpenAIRE

Carrascosa Alís, Jaime; Martínez Sala, Salvador; Martínez-Torregrosa, Joaquín

1998-01-01

Cuando la energía mecánica disminuye, los objetos se calientan. ¿Hay alguna relación entre los cambios en propiedades mecánicas y térmicas?. La termología (con su hipótesis del "calórico") y sus límites con la mecánica: ¿cómo explicar que aumente la temperatura de todos los cuerpos cuando hay rozamiento?. Los trabajos de Joule. Generalización de la conservación de la energía. ¿Si la energía siempre se conserva en un sistema aislado, por qué hablamos de "crisis energética"?. Análisis de las ca...

Diagnóstico energético en el proceso de molienda de la laterita

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Reynaldo Laborde-Brown

2004-03-01

Full Text Available El consumo específico de energía en el proceso de molienda del mineral laterítico en la empresa Comandante Ernesto Che Guevara de Moa no muestra un comportamiento estable, lo que repercute en el aumento de los costos de producción. Para determinar las causas que originan estas variaciones se realizó una investigación en la unidad de molienda, específicamente en sus dos equipos principales: el molino de bolas y el ventilador de recirculación. Los resultados arrojaron que la variabilidad observada en el consumo energético se debe, fundamentalmente, a la ausencia de estabilidad en el flujo de alimentación de los molinos. Se obtiene un modelo estadístico que permite predecir el comportamiento del consumo específico de energía en función de la productividad diaria de la sección de molienda.

Efectos de la entropía urbana en el coste energético del trasporte

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Francisco Bascuñán Walker

2011-05-01

Full Text Available El objetivo del trabajo presentado fue descubrir los efectos de la diversidad de uso de suelo o entropía urbana sobre el gasto energético del transporte. Se eligió como zona de estudio la ciudad de La Serena y se encuestó a un grupo representativo de familias con gastos energéticos y de estratos sociales diversos y se comparó con las zonas urbanas de diferentes grados de entropía. El estudio mostró que, indistintamente del nivel social, los habitantes de las zonas que mostraban niveles mayores de entropía gastaban menos energía en traslados a destinos urbanos que aquellos que vivían en zonas de menores entropías. Basados en los resultados del estudio se concluyó que para disminuir el gasto energético en trasporte de los habitantes de la ciudad se requería incrementar el nivel de entropía. La alternativa más eficiente estudiada fue contemplar en la planificación urbana, pequeños policentros de multiservicios (más de tres servicios diferentes que cubran una superficie de población urbana de 78 has aproximadamente.

Single-Molecule Studies of Bacterial Protein Translocation

NARCIS (Netherlands)

Kedrov, Alexej; Kusters, Ilja; Driessen, Arnold J. M.

2013-01-01

In prokaryotes, a large share of the proteins are secreted from the cell through a process that requires their translocation across the cytoplasmic membrane. This process is mediated by the universally conserved Sec system with homologues in the endoplasmic reticulum and thylakoid membranes of

Desiccation induces accumulations of antheraxanthin and zeaxanthin in intertidal macro-alga Ulva pertusa (Chlorophyta.

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Xiujun Xie

Full Text Available For plants and algae, exposure to high light levels is deleterious to their photosynthetic machineries. It also can accelerate water evaporation and thus potentially lead to drought stress. Most photosynthetic organisms protect themselves against high light caused photodamages by xanthophyll cycle-dependent thermal energy dissipation. It is generally accepted that high light activates xanthophyll cycle. However, the relationship between xanthophyll cycle and drought stress remains ambiguous. Herein, Ulva pertusa (Chlorophyta, a representative perennial intertidal macro-algae species with high drought-tolerant capabilities and simple structures, was used to investigate the operation of xanthophyll cycle during desiccation in air. The results indicate that desiccation under dim light induced accumulation of antheraxanthin (Ax and zeaxanthin (Zx at the expense of violaxanthin (Vx. This accumulation could be arrested by dithiothreitol completely and by uncoupler (carbonyl cyanide p-trifluoromethoxyphenylhydrazone partially, implying the participation of Vx de-epoxidase in conversion of Vx to Ax and Zx. Treatment with inhibitors of electron transport along thylakoid membrane, e.g. DCMU, PG and DBMIB, did not significantly arrest desiccation-induced accumulation of Ax and Zx. We propose that for U. pertusa, besides excess light, desiccation itself could also induce accumulation of Ax and Zx. This accumulation could proceed without electron transport along thylakoid membrane, and is possibly resulting from the reduction of thylakoid lumen volume during desiccation. Considering the pleiotropic effects of Ax and Zx, accumulated Ax and Zx may function in protecting thylakoid membrane and enhancing thermal quenching during emersion in air.

Climatización de una vivienda con energía geotérmica

OpenAIRE

González Elosua, Ignacio Isaías

2013-01-01

El presente proyecto consiste en el estudio, diseño y definición de una instalación de aprovechamiento de energía geotérmica para la climatización a lo largo de todo el año de una vivienda unifamiliar en la localidad de Fornells en el término municipal de Es Mercadal, en Menorca. Para ello, se ha calculado la demanda energética térmica requerida por la vivienda debido a su forma arquitectónica, materiales empleados y necesidades interiores, siguiendo criterios legales, funcionales y constr...

Energía eólica en España

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Cayetano Espejo Marín

2004-01-01

Full Text Available Desde mediados de los años noventa se ha producido en España una expansiónextraordinaria del aprovechamiento de la energía eólica para la generación de electrici-dad. La disponibilidad de zonas con potencial eólico estimable junto con las políticas deapoyo a las energías renovables, sobre todo a la eólica, han contribuido a un enormedesarrollo industrial y tecnológico de este sector. España es líder mundial, tanto enpotencia instalada, donde ocupa el tercer puesto detrás de Alemania y Estados Unidos,como en número y volumen de empresas que participan en los distintos ámbitos de laenergía eólica. En este artículo se analizan las características del sector eólico español.

Planeamiento estratégico del sector de las fuentes no convencionales de energía renovable en Colombia

OpenAIRE

Torres Wilches, Carlos Rolando; Rojas Patiño, Alejandro; Higuera Rincón, Diana Astrid; Hernández Henríquez, Jorge Daniel; Calle Forero, Jorge Alberto

2017-01-01

xiv, 192 h. : il. ; 30 cm. A través de los años y en el ámbito mundial, la generación de energía eléctrica por medio de fuentes no convencionales de energía como el sol, el viento, la biomasa, y la energía mareomotriz, ha estado creciendo constantemente tanto en capacidad instalada (i.e., megawatt) como en número de proyectos implementados. Parte importante de este crecimiento se debe a la mejora continua en la tecnología de producción que utilizan entre otros los paneles so...

Desarrollo de pigmentos cerámicos multifuncionales orientados a la mejora de la eficiencia energética en edificación

OpenAIRE

Aranzabe Basterrechea, Estíbaliz

2017-01-01

268 p. El sector de la edificación y en concreto la climatización de edificios es un sectorprioritario a la hora de implementar mejoras de eficiencia energética. Así lo demuestrala estrategia energética de la Unión Europea (objetivo 20-20-20) y la EstrategiaEnergética de Euskadi 2020 que establecen claras líneas de actuación entre las cuales seencuentra la reducción del consumo de energía en los edificios y en el hogar.La rehabilitación de edificios se presenta como una de las claves para ...

Desarrollo de un modelo de determinación de cash-flows para un proyecto de energía eólica

OpenAIRE

Irene Clara Pisón Fernández; Félix Puime Guillén; Miguel Ángel Crespo Cibrán

2015-01-01

En este trabajo se analiza la problemática asociada a la producción de energía eléctrica de origen renovable, y se ofrece un modelo de definición de las variables en las que se apoya el plan de negocio de energía eólica. El plan de viabilidad muestra que los cash-flows para el accionista obtenidos en este tipo de proyectos permiten afrontar las inversiones futuras con una rentabilidad suficiente, que apunta al sector de energías renovables, y en particular al de energía eólica, como estratégi...

[THE EFFECT OF ACID RAIN ON ULTRASTRUCTURE AND FUNCTIONAL PARAMETERS OF PHOTOSYNTHETIC APPARATUS OF PEA LEAVES].

Science.gov (United States)

Polishchuk, A V; Vodka, M V; Belyavskaya, N A; Khomochkin, A P; Zolotareva, E K

2016-01-01

The effects of simulated acid rain (SAR) on the ultrastructure and functional parameters of the photosynthetic apparatus were studied using 14-day-old pea leaves as test system. Pea plants were sprayed with an aqueous solution containing NaNO₃(0.2 mM) and Na₂SO₄(0.2 mM) (pH 5.6, a control variant), or with the same solution, which was acidified to pH 2.5 (acid variant). Functional characteristics were determined by chlorophyll fluorescence analysis. Acid rain application caused reduction in the efficiency of the photosynthetic electron transport by 25%, which was accompanied by an increase by 85% in the quantum yield of thermal dissipation of excess light quanta. Ultrastructural changes in chloroplast were registered by transmission electron microscopy (TEM) after two days of the SAR-treatment of pea leaves. In this case, the changes in the structure of grana, heterogeneity of thylakoids packaging in granum, namely, the increase of intra-thylakoid gaps and thickness of granal thylakoids compared to the control were found. The migration of protein complexes in thylakoid membranes of chloroplasts isolated from leaves treated with SAR was suppressed. It was shown also that carbonic anhydrase activity was inhibited in chloroplast preparations isolated from SAR-treated pea leaves. We proposed a hypothesis on the possible inactivation of thylakoid carbonic anhydrase under SAR and its involvement in the inhibition of photochemical activity of chloroplasts. The data obtained allows to suggest that acid rains negatively affect the photosynthetic apparatus disrupting the membrane system of chloroplast.

Seguridad energética rusa: entre Europa y China

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Antonio Sánchez

2008-05-01

Full Text Available Dentro de la seguridad energética rusa aparece como una debilidad importante la concentración de recursos en unos pocos clientes, en concreto en la UE. Por este motivo, las autoridades rusas están tratando de diversificar destinos de venta, tratando de abrir otros mercados, en especial en extremo oriente y, en particular en China. Esto acrecienta su seguridad energética, pero debilita la europea en caso de que la UE no adopte medidas activas. El abastecimiento a Europa desde Rusia, especialmente de gas, depende también de tres grandes limitaciones. En primer lugar, que existan nuevos yacimientos y su posibilidad de movilizarlos conforme aumenten las necesidades europeas. En segundo lugar, aparece el problema del surgimiento de competidores por el gas ruso y, en particular, recientemente se ha subrayado el papel de China como futuro cliente de gas ruso. En tercer lugar, se encuentra la posibilidad de que Rusia pueda ejercer un control especial sobre la oferta de gas mundial, que condicione en cantidad o/y precio el abastecimiento a Europa.

Isolation of plant Photosystem II complexes by fractional solubilization

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Patrycja eHaniewicz

2015-12-01

Full Text Available PSII occurs in different forms and supercomplexes in thylakoid membranes. Using a transplastomic strain of Nicotiana tabacum histidine tagged on the subunit PsbE, we have previously shown that a mild extraction protocol with β-dodecylmaltoside enriches PSII characteristic of lamellae and grana margins. Here, we characterize residual granal PSII that is not extracted by this first solubilization step. Using affinity purification, we demonstrate that this PSII fraction consists of PSII-LHCII mega- and supercomplexes, PSII dimers and PSII monomers, which were separated by gel filtration and functionally characterized. Our findings represent an alternative demonstration of different PSII populations in thylakoid membranes, and they make it possible to prepare PSII-LHCII supercomplexes in high yield.

De molinos y quijotes. Energía eólica y cooperativismo en el sur bonaerense

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Luciana Clementi

2014-06-01

Full Text Available El constante aumento en la demanda de energía evidenciado en Argentina, sumado al fuerte interés nacional por alcanzar mayor seguridad energética, profundiza la necesidad de nuevas inversiones en el sector energético. Sin embargo, la dependencia que sufre el país en relación a los hidrocarburos hace peligrar el abastecimiento en el largo plazo. En este contexto, aparecen en la última década proyectos de producción de energía renovable, incentivados por un contexto mundial donde se alienta el desarrollo de fuentes energéticas que contribuyan a avanzar hacia un modelo más sustentable. En este escenario, interesa en este trabajo analizar el rol de las cooperativas eléctricas fuertemente ancladas en la Provincia de Buenos Aires, en la ejecución de proyectos locales que contemplan la producción de energía eólica en el Sur bonaerense, para reflexionar acerca de las oportunidades y barreras a las que se enfrentan. The constant increase of energy demands in Argentina together with the strong national interest to obtain a higher energy security, deepens the need of new investments in the energy sector. However, the dependence of the country on hidrocarbons threatens the supply in the long-term. In this context appear in the last decade, renewable energy production projects, triggered by a global context which encourages the development of energy sources that favor a cleaner and more sustainable model. In this scenario, it is of interest in this paper to analyze the role of cooperatives of electricity well-established in the Province of Buenos Aires, mainly in the performance of local projects that consider eolic energy production in the South of Buenos Aires, in order to reflect upon the new opportunities as well as the barriers they must deal.

Avaliação da eficiência energética em uma indústria de painéis compensado

OpenAIRE

Silva, Dimas Agostinho da

2013-01-01

Este trabalho trata do perfil e do uso de energia em uma indústria de painéis compensado no Brasil. O seu objetivo geral é corroborar para a melhoria da competitividade da indústria de compensado nacional. Especificamente visou conhecer o perfil do consumo energético na indústria, avaliar possibilidade de ganhos de eficiência no componente energético do processo produtivo e disponibilizar modelos matemáticos de consumo energético aplicado às indústrias de painéis compensado. O trabalho foi de...

Proyectos pilotos WHIX de energía renovable y seguridad ambiental en El Salvador.

OpenAIRE

Ochoa Córdova, Carlos Roberto

2008-01-01

El Programa WHIX aporta proyectos de Energía y Medio Ambiente para abrir un diálogo entre los militares de la Región, organizaciones gubernamentales y no-gubernamentales y sus equivalentes en los EE.UU. Este programa cataliza proyectos de energía renovable y el medioambiente para demostrar y validar estas tecnologías en los países de la región. Al mismo tiempo provee un foro de intercambio internacional de las “Mejores Prácticas” y la oportunidad de trabajar en conjunto en promisorias investi...

Reference: 673 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available et al. 2007 Dec. J. Biol. Chem. 282(49):35945-53. Polar lipid trafficking is essential in eukaryotic cells as membranes... of lipid assembly are often distinct from final destination membranes. A striking example is the... biogenesis of the photosynthetic membranes (thylakoids) in plastids of plants. L...ipid biosynthetic enzymes at the endoplasmic reticulum and the inner and outer plastid envelope membranes ar

Evaluación de las medidas de eficiencia energética para la estación antártica ecuatoriana Pedro Vicente Maldonado a través del modelo de energía calibrada para edificaciones

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Isabel Miño

2015-08-01

Full Text Available En la Antártica, un continente sensible a las actividades humanas y un lugar estratégico para la investigación de los efectos producidos por el cambio climático, es importante que los proyectos desarrollados ahí minimicen su impacto medioambiental. Bajo este concepto, la estación antártica Pedro Vicente Maldonado, construida en 1990 y operada por Ecuador durante el verano austral, se convertirá dentro de pocos años en una estación permanente. Por ello y con el fin de optimizar el consumo energético, se han analizado diversas medidas de eficiencia energética de acuerdo a un modelo energético basado en el actual consumo de diésel para calefacción. Los resultados de este estudio demuestran que los elementos de la envolvente del edificio, por donde se pierde gran parte de la energía, son el piso y el techo. Por otro lado, debido a la baja relación ventana-paredes de la estación, la reducción en el consumo de diésel generado por el uso de vidrios triple y cuádruple no es significativa. Al combinar diferentes medidas de eficiencia energética, se puede ahorrar hasta un 50% del consumo anual de diésel para calefacción si se compara con el consumo que tendría la estación actual operando en forma permanente. Este estudio servirá de referencia para implementar los cambios necesarios en dicha estación.

Functional update of the auxiliary proteins PsbW, PsbY, HCF136, PsbN, TerC and ALB3 in maintenance and assembly of PSII

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Magdalena ePlöchinger

2016-04-01

Full Text Available Assembly of Photosystem (PS II in plants has turned out to be a highly complex process which, at least in part, occurs in a sequential order and requires many more auxiliary proteins than subunits present in the complex. Owing to the high evolutionary conservation of the subunit composition and the three-dimensional structure of the PSII complex, most plant factors involved in the biogenesis of PSII originated from cyanobacteria and only rarely evolved de novo. Furthermore, in chloroplasts the initial assembly steps occur in the non-appressed stroma lamellae, whereas the final assembly including the attachment of the major LHCII antenna proteins takes place in the grana regions. The stroma lamellae are also the place where part of PSII repair occurs, which very likely also involves assembly factors. In cyanobacteria initial PSII assembly also occurs in the thylakoid membrane, in so-called thylakoid centres, which are in contact with the plasma membrane. Here, we provide an update on the structures, localisations, topologies, functions, expression and interactions of the low molecular mass PSII subunits PsbY, PsbW and the auxiliary factors HCF136, PsbN, TerC and ALB3, assisting in PSII complex assembly and protein insertion into the thylakoid membrane.

A novel potassium channel in photosynthetic cyanobacteria.

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Manuela Zanetti

Full Text Available Elucidation of the structure-function relationship of a small number of prokaryotic ion channels characterized so far greatly contributed to our knowledge on basic mechanisms of ion conduction. We identified a new potassium channel (SynK in the genome of the cyanobacterium Synechocystis sp. PCC6803, a photosynthetic model organism. SynK, when expressed in a K(+-uptake-system deficient E. coli strain, was able to recover growth of these organisms. The protein functions as a potassium selective ion channel when expressed in Chinese hamster ovary cells. The location of SynK in cyanobacteria in both thylakoid and plasmamembranes was revealed by immunogold electron microscopy and Western blotting of isolated membrane fractions. SynK seems to be conserved during evolution, giving rise to a TPK (two-pore K(+ channel family member which is shown here to be located in the thylakoid membrane of Arabidopsis. Our work characterizes a novel cyanobacterial potassium channel and indicates the molecular nature of the first higher plant thylakoid cation channel, opening the way to functional studies.

The absence of chlorophyll b affects lateral mobility of photosynthetic complexes and lipids in grana membranes of Arabidopsis and barley chlorina mutants.

Science.gov (United States)

Tyutereva, Elena V; Evkaikina, Anastasiia I; Ivanova, Alexandra N; Voitsekhovskaja, Olga V

2017-09-01

The lateral mobility of integral components of thylakoid membranes, such as plastoquinone, xanthophylls, and pigment-protein complexes, is critical for the maintenance of efficient light harvesting, high rates of linear electron transport, and successful repair of damaged photosystem II (PSII). The packaging of the photosynthetic pigment-protein complexes in the membrane depends on their size and stereometric parameters which in turn depend on the composition of the complexes. Chlorophyll b (Chlb) is an important regulator of antenna size and composition. In this study, the lateral mobility (the mobile fraction size) of pigment-protein complexes and lipids in grana membranes was analyzed in chlorina mutants of Arabidopsis and barley lacking Chlb. In the Arabidopsis ch1-3 mutant, diffusion of membrane lipids decreased as compared to wild-type plants, but the diffusion of photosynthetic complexes was not affected. In the barley chlorina f2 3613 mutant, the diffusion of pigment-protein complexes significantly decreased, while the diffusion of lipids increased, as compared to wild-type plants. We propose that the size of the mobile fractions of pigment-protein complexes in grana membranes in vivo is higher than reported previously. The data are discussed in the context of the protein composition of antennae, characteristics of the plastoquinone pool, and production of reactive oxygen species in leaves of chlorina mutants.

Atomic force microscopy studies of native photosynthetic membranes.

Science.gov (United States)

Sturgis, James N; Tucker, Jaimey D; Olsen, John D; Hunter, C Neil; Niederman, Robert A

2009-05-05

for quinones to diffuse freely. Measurement of the intercomplex distances between adjacent LH2 rings of Phaeospirillum molischianum has permitted the first calculation of the separation of bacteriochlorophyll a molecules in the native ICM. A recent AFM analysis of the organization of green plant photosystem II (PSII) in grana thylakoids revealed the protruding oxygen-evolving complex, crowded together in parallel alignment at three distinct levels of stacked membranes over the lumenal surface. The results also confirmed that PSII-LHCII supercomplexes are displaced relative to one another in opposing grana membranes.

The role of fluid compression in energy conversion and particle energization during magnetic reconnection

Science.gov (United States)

Li, X.; Guo, F.; Li, G.; Li, H.

2016-12-01

Theories of particle transport and acceleration have shown that fluid compression is the leading mechanism for particle acceleration and plasma energization. However, the role of compression in particle acceleration during magnetic reconnection is unclear. We use two approaches to study this issue. First, using fully kinetic simulations, we quantitatively calculate the effect of compression in energy conversion and particle energization during magnetic reconnection for a range of plasma beta and guide field. We show that compression has an important contribution for the energy conversion between the bulk kinetic energy and the internal energy when the guide field is smaller than the reconnecting component. Based on this result, we then study the large-scale reconnection acceleration by solving the Parker's transport equation in a background reconnecting flow provided by MHD simulations. Due to the compression effect, the simulations suggest fast particle acceleration to high energies in the reconnection layer. This study clarifies the nature of particle acceleration in reconnection layer, and may be important to understand particle acceleration and plasma energization during solar flares.

Estudio regional del potencial de secado con aire natural y energía solar

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Jorge Domínguez P.

1983-09-01

Full Text Available En este artículo se presenta y aplica una metodología de trabajo basada en la técnica de simulación matemática y desarrollada con el fin de realizar estudios sobre el potencial de secado de productos agropecuarios con aire natural y energía solar de regiones tropicales. La metodología se basa en el uso de un programa de computador e Incluye otros elementos metodológicos en relación con el manejo de la información meteorológica, el patrón de operación del ventilador, el uso de energía solar y la interpretación de los resultados con el fin de optimizar el sistema. Se reportan los resultados del estudio del potencial de secado con aire natural y energía solar de Tuluá (Valle y se proporcionan recomendaciones específicas para la implementación de sistemas de secado a bala temperatura en la Reglón.

Anionic lipids and the cytoskeletal proteins MreB and RodZ define the spatio-temporal distribution and function of membrane stress controller PspA in Escherichia coli.

Science.gov (United States)

Jovanovic, Goran; Mehta, Parul; Ying, Liming; Buck, Martin

2014-11-01

All cell types must maintain the integrity of their membranes. The conserved bacterial membrane-associated protein PspA is a major effector acting upon extracytoplasmic stress and is implicated in protection of the inner membrane of pathogens, formation of biofilms and multi-drug-resistant persister cells. PspA and its homologues in Gram-positive bacteria and archaea protect the cell envelope whilst also supporting thylakoid biogenesis in cyanobacteria and higher plants. In enterobacteria, PspA is a dual function protein negatively regulating the Psp system in the absence of stress and acting as an effector of membrane integrity upon stress. We show that in Escherichia coli the low-order oligomeric PspA regulatory complex associates with cardiolipin-rich, curved polar inner membrane regions. There, cardiolipin and the flotillin 1 homologue YqiK support the PspBC sensors in transducing a membrane stress signal to the PspA-PspF inhibitory complex. After stress perception, PspA high-order oligomeric effector complexes initially assemble in polar membrane regions. Subsequently, the discrete spatial distribution and dynamics of PspA effector(s) in lateral membrane regions depend on the actin homologue MreB and the peptidoglycan machinery protein RodZ. The consequences of loss of cytoplasmic membrane anionic lipids, MreB, RodZ and/or YqiK suggest that the mode of action of the PspA effector is closely associated with cell envelope organization. © 2014 The Authors.

El sub-sector de distribución de energía eléctrica en Colombia

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Mauricio Martín Delvasto

1999-07-01

Full Text Available El sector de energía eléctrica en Colombia, ha experimentado en los últimos 18 meses una transformación total que persigue la utilización eficiente de los recursos, además de tener el control administrativo y operacional de las empresas de generación y distribución de energía con el propósito de lograr mayor cobertura nacional y aumentar considerablemente la calidad en la prestación del servicio de energía. A continuación se describen los principales elementos, incluyendo aquellos de naturaleza financiera, que originaron su transformación, así como los resultados, a corto y mediano plazo que se pretenden obtener con los procesos de privatización de un sector, sin ninguna duda, fundamental para el desarrollo de nuestro país.

Impacto de programas de eficiencia energética eléctrica, estudio de caso: Empresas alimentarias en Cuenca, Ecuador

Directory of Open Access Journals (Sweden)

Galo Carrillo-Rojas

2014-01-01

Full Text Available El estudio exploratorio muestra los resultados de aplicación de programas de eficiencia energética eléctrica en 7 empresas alimentarias en Cuenca, Ecuador. La investigación contempló fases de diagnóstico, intervención y evaluación. Se condujo un análisis comparativo entre las empresas: consumo de energía versus producción, análisis de calidad de energía, relación cumplimiento/consumo específico de energía, e impacto sobre emisiones CO2. Los resultados revelaron que la aceptación hacia las recomendaciones de ahorro, se basa en el nivel de inversión y la voluntad/disponibilidad administrativa. El estudio mostró que las intervenciones tuvieron un efecto parcial sobre la reducción del consumo específico de energía en 4 empresas. Adicionalmente se obtuvo un efecto positivo en la corrección de factor de potencia en una empresa y en la mejora del balance de corriente en 5. La investigación mostró la existencia de una reducción significativa de emisiones post-intervención, resaltando la efectividad de los programas.

Desarrollo de un modelo de determinación de cash-flows para un proyecto de energía eólica

Directory of Open Access Journals (Sweden)

Irene Clara Pisón Fernández

2015-06-01

Full Text Available En este trabajo se analiza la problemática asociada a la producción de energía eléctrica de origen renovable, y se ofrece un modelo de definición de las variables en las que se apoya el plan de negocio de energía eólica. El plan de viabilidad muestra que los cash-flows para el accionista obtenidos en este tipo de proyectos permiten afrontar las inversiones futuras con una rentabilidad suficiente, que apunta al sector de energías renovables, y en particular al de energía eólica, como estratégico dentro de la economía española de las próximas décadas.

Removal of phenol from water : a comparison of energization methods

NARCIS (Netherlands)

Grabowski, L.R.; Veldhuizen, van E.M.; Rutgers, W.R.

2005-01-01

Direct electrical energization methods for removal of persistent substances from water are under investigation in the framework of the ytriD-project. The emphasis of the first stage of the project is the energy efficiency. A comparison is made between a batch reactor with a thin layer of water and

Innovació en el procés de realització d'auditories energètiques. De l'auditoria tradicional a l'auditoria virtual

OpenAIRE

Utges Mampel, Daniel

2016-01-01

Aquest projecte planteja un nou prisma a la hora de realitzar auditories energètiques a les instal·lacions, passant d’una auditoria tradicional a una auditoria virtual, utilitzant tècniques estadístiques i la caracterització matemàtica de potencials millores d’eficiència energètica. L’auditoria virtual és un gran avenç en el sector de l’eficiència energètica, resultant en una innovació disruptiva en el sector, doncs permet reduir els costos i el temps d’entrega d’una auditoria energètica e...

Mejoras energéticas en un horno industrial de una empresa petr oquímica

OpenAIRE

Moldovan, Gabriel Ionut

2016-01-01

Treball Final de Grau en Enginyeria en Tecnologies Industrials. Codi: ET1040. Curs: 2015/2016 El problema energético mundial se resume en que nuestra bonanza social y económica, nuestra tecnología y nuestra sociedad dependen enormemente de la sobreexplotación de recursos naturales no renovables. La situación energética actual es insostenible a largo plazo y las consecuencias de seguir igual en el futuro serían devastadoras. Es necesario pues, un cambio de rumbo aunque la situa...

La energía electrica, dentro de la estructura tecnológica de la industria antioqueña

Directory of Open Access Journals (Sweden)

Gustavo López Alvarez

1991-07-01

Full Text Available En este artículo se presenta una visión general de la estructura tecnológica de la industria antioqueña en su conjunto para el periodo 1975-1987. Para el análisis se supone una función de producción en dos niveles: en el primero se emplean como insumos el capital, el trabajo, los energéticos y otras materias primas; en el segundo, los energéticos son desagregados en electricidad y otros. Usando una función translogarítmica de costos para cada uno de los niveles, se llega, finalmente, a presentar estimaciones de las elasticidades precio directas y cruzadas que darían cuenta de las relaciones económicas entre los insumos. Examinando los resultados de las estimaciones se observa que las elasticidades directas son todas negativas, el capital y los insumos energéticos son sustitutivos, mientras que la única complementariedad se presenta entre el trabajo y los insumos energéticos.

Photoprotection vs. Photoinhibition of Photosystem II in Transplastomic Lettuce (Lactuca sativa) Dominantly Accumulating Astaxanthin.

Science.gov (United States)

Fujii, Ritsuko; Yamano, Nami; Hashimoto, Hideki; Misawa, Norihiko; Ifuku, Kentaro

2016-07-01

Transplastomic (chloroplast genome-modified; CGM) lettuce that dominantly accumulates astaxanthin grows similarly to a non-transgenic control with almost no accumulation of naturally occurring photosynthetic carotenoids. In this study, we evaluated the activity and assembly of PSII in CGM lettuce. The maximum quantum yield of PSII in CGM lettuce was <0.6; however, the quantum yield of PSII was comparable with that in control leaves under higher light intensity. CGM lettuce showed a lower ability to induce non-photochemical quenching (NPQ) than the control under various light intensities. The fraction of slowly recovering NPQ in CGM lettuce, which is considered to be photoinhibitory quenching (qI), was less than half that of the control. In fact, 1 O 2 generation was lower in CGM than in control leaves under high light intensity. CGM lettuce contained less PSII, accumulated mostly as a monomer in thylakoid membranes. The PSII monomers purified from the CGM thylakoids bound echinenone and canthaxanthin in addition to β-carotene, suggesting that a shortage of β-carotene and/or the binding of carbonyl carotenoids would interfere with the photophysical function as well as normal assembly of PSII. In contrast, high accumulation of astaxanthin and other carbonyl carotenoids was found within the thylakoid membranes. This finding would be associated with the suppression of photo-oxidative stress in the thylakoid membranes. Our observation suggests the importance of a specific balance between photoprotection and photoinhibition that can support normal photosynthesis in CGM lettuce producing astaxanthin. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

La imagen electrónica de la energía. Estudio estético y funcional de las páginas webs de las compañías del sector energético

OpenAIRE

Álvarez Ruiz, Antón; Reyes Moreno, María Isabel

2011-01-01

Este artículo analiza las páginas webs de las principales compañías operantes en el sector de la energía (electricidad y gas) de los países más desarrollados. La situación actual del mercado es muy significativa. Por primera vez en la historia, las administraciones centrales de estos países han consentido liberalizar el mercado energético. Y, aunque este proceso avanza con gran lentitud, comienzan a notarse cambios que anticipan un proceso de concentración, a través de compras, fusiones y ...

Particle energization by inertial Alfven wave in auroral ionosphere

Science.gov (United States)

Kumar, S.

2017-12-01

The role of inertial Alfven wave in auroral acceleration region and in the inertial regime to energize the plasma particles is an interesting field and widely discussed observationally as well as theoretically in recent years. In this work, we present the density perturbations by inertial Alfvén wave (AW) in the auroral ionosphere. We obtain dynamical equations for inertial AW and fast mode of AW using two-fluid model and then solve them numerically in order to analyze the localized structures and cavity formation. The ponderomotive force due to the high frequency inertial AW changes the background density and is believed to be responsible for the wave localization or for the formation of density cavities in auroral ionosphere. These density cavities are believed to be the sites for particle energization. This perturbed density channel grow with time until the modulation instability acquires steady state. We find that the density cavities are accompanied by the high amplitude magnetic fields. The amplitude of the strongest density cavity is estimated as ˜ 0.26n0 (n0 is unperturbed plasma number density). The results presented here are found consistent with the observational studies using FAST spacecraft.

Eficiencia energética y confort en edificios de oficina: El caso alemán

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Ernesto Kuchen

2012-12-01

Full Text Available La construcción de edificios en los últimos 15 años en Europa persigue el objetivo común de dar respuesta al problema de la Eficiencia Energética y el Confort en espacios de trabajo. Las propuestas de cambio se inclinan por el desarrollo de una arquitectura “transparente”, con extensas superficies de vidrio expuestas. Dicha práctica se hace llamar ecológica y sustentable. Con el tiempo, el uso y la experiencia ponen en alerta a científicos del área. El objetivo del trabajo es detectar los aspectos más relevantes que afectan la Eficiencia Energética (EE y el Confort de espacios reales de trabajo para la elaboración apropiada de herramientas de diseño y cálculo. Para ello, se lleva a cabo un trabajo de campo en base a mediciones y encuestas en 19 edificios de oficina, en Alemania. Del monitoreo energético y del análisis del Confort se detectan potenciales de optimización. Se observa que la EE no se logra al conectar el edificio a la red energética una vez finalizada la obra arquitectónica. Por el contrario, la planificación integral, el monitoreo y el seguimiento en la vida útil del edificio permiten corregir y lograr mejores niveles de EE y Confort.

Investigation of Prevalence of Energizer Drugs and Supplements Consumption and Effective Factors Among Bodybuilder Men in Karaj (2011

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F. Shoshtarizadeh

2013-08-01

Full Text Available Background: Body builder athletes’ high attention to form of body can result in high prevalence of nutritional disorders and habit to energizer drugs consumption. With notice to abuse problems of these drugs, this research was carried out to estimate prevalence of energizer drugs and supplements consumption in Karaj body builder men in 2011. Method: In cross-sectional (description- analytical research 780 Karaj body builder men were selected randomly. Data were collected through interview with questionnaires containing demographic questions and using information of drugs. Data were analyzed with SPSS software (Ver. 19 and κ² test with meaningful level of P<0.05. Result: Prevalence of consumption in studied sample from different types of supplements and energizer drugs was estimated 88.2%. The most consumption prevalence belonged to food supplements and vitamins group and combination of those (69.9%. About anabolic and energizer compounds and also hormonal drugs and corticosteroids, prevalence was 5.6% and 2.1% respectively and 7.7% totally. There was meaningful relation between experience times of abuse problems, place of drug and supplement supply and attention to being permissible or impermissible of those items with type of drugs or supplement (P = 0.001. Also relation between consumption of supplements and drugs with main goal in using them was meaningful (P = 0.045. Conclusion: Consumption of supplement and energizer drugs in Karaj body builder men has high prevalence.

Pick-up ion energization at the termination shock

Energy Technology Data Exchange (ETDEWEB)

Gary, S Peter [Los Alamos National Laboratory; Winske, Dan [Los Alamos National Laboratory; Wu, Pin [BOSTON UNIV.; Schwadron, N A [BOSTON UNIV.

2009-01-01

One-dimensional hybrid simulations are used to investigate how pickup ions are energized at the perpendicular termination shock. Contrary to previous models based on pickup ion energy gain by repeated crossings of the shock front (shock surfing) or due to a reforming shock front, the present simulations show that pickup ion energy gain involves a gyro-phasedependent interaction with the inhomogeneous motional electric field at the shock. The process operates at all relative concentrations of pickup ion density.

Modelo de innovación y optimización de la energía solar en España. La aplicación de las tecnologías disponibles para el aprovechamiento de recursos, comercialización y beneficios de la energía solar

OpenAIRE

González Peña, Daniel

2016-01-01

Tesis Doctoral leída en la Universidad Rey Juan Carlos de Madrid en 2014. Directora de la Tesis: Dra. Carmen de Pablos Heredero En esta Tesis Doctoral se pretende analizar los límites, tanto a medio como a largo plazo, de la competitividad económica de la energía solar en España, estudiando el nivel de evolución que presuntamente debería tener esta forma de producción de energía, hasta conseguir llegar a ser competitiva con las energías fósiles, y otras fuentes emergentes en desarrollo. ...

Climatización de vivienda a partir de energía geotérmica de baja entalpía

OpenAIRE

Alfaro del Moral, Ignacio

2015-01-01

El TFG está centrado en la energía geotérmica utilizada para la climatización de una vivienda. Se elige una vivienda a la que se desea realizar una instalación geotérmica, de modo que una vez se ha realizado un estudio de la misma, se lleva a cabo un amplio estudio de la fuente renovable (tipos de energía, tipos de yacimientos, situación de la energía geotérmica, componentes del sistema, diseño del sistema, etc.). El proyecto desemboca en la elección de los componentes geotérmicos ideales par...

Principio de la conservación de la energía mecánica en caída libre

OpenAIRE

Carmona Franco, José Edgar; Amaya Díaz, José Alexander; Salcedo Rodríguez, Karen Lizeth

2007-01-01

Para estudiar el principio de la conservación de la energía mecánica utilizamos un movimiento uniformemente acelerado como lo es la caída libre, en el cual se puede mostrar como son las interacciones entre la energía cinética Ec y la energía potencial Ep, con relación a una altura arbitraria, y así poder demostrar la veracidad de este principio en dicho movimiento, registrando el tiempo empleado por un balín entre un electroimán y en sensor acústico por un cronómetro digital. To study the...

The Contribution of Compressional Magnetic Pumping to the Energization of the Earth's Outer Electron Radiation Belt During High-Speed Stream-Driven Storms

Science.gov (United States)

Borovsky, Joseph E.; Horne, Richard B.; Meredith, Nigel P.

2017-12-01

Compressional magnetic pumping is an interaction between cyclic magnetic compressions and pitch angle scattering with the scattering acting as a catalyst to allow the cyclic compressions to energize particles. Compressional magnetic pumping of the outer electron radiation belt at geosynchronous orbit in the dayside magnetosphere is analyzed by means of computer simulations, wherein solar wind compressions of the dayside magnetosphere energize electrons with electron pitch angle scattering by chorus waves and by electromagnetic ion cyclotron (EMIC) waves. The magnetic pumping is found to produce a weak bulk heating of the electron radiation belt, and it also produces an energetic tail on the electron energy distribution. The amount of energization depends on the robustness of the solar wind compressions and on the amplitude of the chorus and/or EMIC waves. Chorus-catalyzed pumping is better at energizing medium-energy (50-200 keV) electrons than it is at energizing higher-energy electrons; at high energies (500 keV-2 MeV) EMIC-catalyzed pumping is a stronger energizer. The magnetic pumping simulation results are compared with energy diffusion calculations for chorus waves in the dayside magnetosphere; in general, compressional magnetic pumping is found to be weaker at accelerating electrons than is chorus-driven energy diffusion. In circumstances when solar wind compressions are robust and when EMIC waves are present in the dayside magnetosphere without the presence of chorus, EMIC-catalyzed magnetic pumping could be the dominant energization mechanism in the dayside magnetosphere, but at such times loss cone losses will be strong.

Is chloroplast import of photosynthesis proteins facilitated by an actin-TOC-TIC-VIPP1 complex?

Science.gov (United States)

Jouhet, Juliette; Gray, John C

2009-10-01

Actin filaments are major components of the cytoskeleton that interact with chloroplast envelope membranes to allow chloroplast positioning and movement, stromule mobility and gravitropism perception. We recently reported that Toc159, a component of the TOC complex of the chloroplast protein import apparatus, interacts directly with actin. The interaction of Toc159 and actin was identified by co-immunoprecipitation and co-sedimentation experiments with detergent-solubilised pea chloroplast envelope membranes. In addition, many of the components of the TOC-TIC protein import apparatus and VIPP1 (vesicle-inducing protein in plastids 1) were identified by mass spectroscopy in the material co-immunoprecipitated with antibodies to actin. Toc159 is the receptor for the import of photosynthesis proteins and VIPP1 is involved in thylakoid membrane formation by inducing vesicle formation from the chloroplast inner envelope membrane, suggesting we may have identified an actin-TOC-TIC-VIPP1 complex that may provide a means of channeling cytosolic preproteins to the thylakoid membrane. The interaction of Toc159 with actin may facilitate exchange between the putative soluble and membrane forms of Toc159 and promote the interaction of cytosolic preproteins with the TOC complex.

A ingestão energética de pacientes em hemodiálise é subrelatada?

Directory of Open Access Journals (Sweden)

Inaiana Marques Filizola Vaz

2015-09-01

Full Text Available ResumoIntrodução:O sub-relato da ingestão energética é pouco estudado na população em hemodiálise.Objetivo:Avaliar o sub-relato da ingestão energética e os fatores associados em pacientes em hemodiálise.Métodos:Estudo transversal, com 344 pacientes adultos estáveis, de dez centros de hemodiálise de Goiânia-GO. A ingestão energética foi avaliada por seis recordatórios de 24 horas e a taxa de metabolismo basal (TMB foi calculada pela equação de Harris Benedict. Foi considerado como sub-relato quando a razão entre a ingestão energética média e a TMB foi menor que 1,27. Para análise dos fatores associados ao sub-relato, foi utilizada a regressão de Poisson com estimativa robusta da variância.Resultados:A prevalência de sub-relato foi de 65,7%, sendo mais expressiva em indivíduos com excesso de peso e nos dias sem diálise. O resultado final da análise multivariada identificou quatro fatores independentemente associados ao sub-relato: sexo feminino (RP = 1,27; IC = 1,10-1,46, índice de massa corporal ≥ 25 kg/m2 (RP = 1,29; IC = 1,12-1,48, três ou menos refeições/dia (RP = 1,31; IC = 1,14-1,51 e tempo de hemodiálise inferior a cinco anos (RP = 1,19; IC = 1,01-1,40.Conclusão:A população avaliada demonstrou elevada prevalência de sub-relato da ingestão energética. Pertencer ao sexo feminino, apresentar excesso de peso, fazer um menor número de refeições diárias e ter menos tempo de hemodiálise foram fatores associados ao sub-relato.

Instalación eléctrica de una vivienda unifamiliar aislada mediante suministro de energías renovables

OpenAIRE

LOZANO VALLADOLID, FERNANDO

2015-01-01

[ES] Instalación eléctrica con grado de electrificación elevada de una vivienda unifamiliar aislada mediante suministro de energías renovables (solar, eólica, geotérmicas). Lozano Valladolid, F. (2015). Instalación eléctrica de una vivienda unifamiliar aislada mediante suministro de energías renovables. http://hdl.handle.net/10251/58751. TFGM

Optimización de variables energéticas en función de la productividad y competitividad de la industria láctea y caracterización energética y tecnológica del sector

OpenAIRE

Bolaños Bolaños, Carlos Alberto

2014-01-01

Debido a la competitividad del mercado y a la incertidumbre de los empresarios industriales por la sostenibilidad de las empresas manufactureras en Colombia, la eficiencia energética se convierte en una de las herramientas principales para el progreso y el no estancamiento de su desarrollo tecnológico y económico. Por ello se debe incentivar a los empresarios para la búsqueda de soluciones y alternativas que giren en torno a la eficiencia energética de sus procesos. Algunas de ellas se desarr...

Estudio del aprovechamiento energético de los puntos de regulación de presión en la red de abastecimiento a Cartagena

OpenAIRE

Vera Morales, Carlos

2015-01-01

El actual sistema energético a nivel mundial está basado en la generación de energía a partir de combustibles fósiles como el petróleo, el carbón mineral y el gas. En la actualidad, la generación de energía a partir de estas materias primas se está replanteando por razones como la limitada disponibilidad de recursos. La Unión Europea tiene como objetivo prioritario la promoción de la electricidad generada a partir de fuentes de energía renovables. Esto se debe a razones dive...

Producción de A.C.S. y climatización de una vivienda unifamiliar con energía geotérmica

OpenAIRE

Martínez Doce, Rubén

2014-01-01

El objetivo de este proyecto fin de carrera es el de realizar un diseño de una instalación para la producción de agua caliente sanitaria (A.C.S.), climatización de las estancias y de una piscina cubierta, de una vivienda unifamiliar mediante energía geotérmica, con el fin de proporcionar un ahorro energético utilizando una energía limpia. Ingeniería Industrial Industria Ingeniaritza

Arabidopsis Tic40 expression in tobacco chloroplasts results in massive proliferation of the inner envelope membrane and upregulation of associated proteins.

Science.gov (United States)

Singh, Nameirakpam Dolendro; Li, Ming; Lee, Sueng-Bum; Schnell, Danny; Daniell, Henry

2008-12-01

The chloroplast inner envelope membrane (IM) plays essential roles in lipid synthesis, metabolite transport, and cellular signaling in plants. We have targeted a model nucleus-encoded IM protein from Arabidopsis thaliana, pre-Tic40-His, by relocating its expression from the nucleus to the chloroplast genome. Pre-Tic40-His was properly targeted, processed, and inserted. It attained correct topology and was folded and assembled into a TIC complex, where it accounted for up to 15% of the total chloroplast protein. These results confirm the existence of a novel pathway for protein targeting to the IM. Tic40-His overexpression resulted in a massive proliferation of the IM (up to 19 layers in electron micrographs) without significant effects on plant growth or reproduction. Consistent with IM proliferation, the expression levels of other endogenous IM proteins (IEP37, PPT, Tic110) were significantly (10-fold) upregulated but those of outer envelope membrane (Toc159), stromal (hsp93, cpn60), or thylakoid (LHCP, OE23) proteins were not increased, suggesting retrograde signal transduction between chloroplast and nuclear genomes to increase lipid and protein components for accommodation of increased accumulation of Tic40. This study opens the door for understanding the regulation of membrane biogenesis within the organelle and the utilization of transgenic chloroplasts as bioreactors for hyperaccumulation of membrane proteins for biotechnological applications.

Propuesta de mejora energética para una planta de producción de clinker

Directory of Open Access Journals (Sweden)

Leonardo Rodriguez Urrego

2017-11-01

Full Text Available El siguiente trabajo presenta un análisis de la eficiencia energética en la industria cementera y un ejemplo real en donde se proponen mejoras para disminuir considerablemente el consumo energético. El aumento de la eficiencia disminuye considerablemente el costo de la energía eléctrica, además de las emisiones de CO2 ayudando así al mantenimiento y la preservación del medio ambiente. El caso de estudio fue aplicado en la planta de producción de cemento de san Vicente del Raspeig operada por CEMEX en España. En este caso se analizó una sección de la planta de producción, donde se realiza la molienda y el ensacado de cemento. Se encontró que, al implementar las mejoras propuestas, el costo de producción disminuye y el punto de equilibrio con respecto a la implementación de estos nuevos equipos no era mayor a 5 años lo cual hace que estas mejoras sean factibles.

ENERGÍA DE BAJA INTENSIDAD: gobiernos, mercados e instituciones en el regionalismo energético de América del Sur

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Stefano Palestini

Full Text Available A pesar de haber sido considerada un área prioritaria de cooperación, el regionalismo energético sudamericano muestra signos de estancamiento, evidenciados por las infructuosas negociaciones de un Tratado Energético Sudamericano. Este artículo explica la paradoja de por qué, no obstante la voluntad política, las favorables condiciones estructurales para la integración, y la creación de instituciones regionales ad hoc, el regionalismo energético no consiguió pasar de las declaraciones intergubernamentales a la implementación de políticas. Se argumenta que ninguna de las instituciones creadas ha sido capaz de mediar la divergencia entre mercados y entre preferencias gubernamentales. Se requiere por tanto de un nuevo consenso que replantee la necesidad y la capacidad de la región para llevar adelante la agenda de integración energética. A un nivel más general, el caso del sector energético brinda lecciones importantes acerca de los desafíos futuros que enfrenta la cooperación regional en materia de políticas públicas en Sudamérica.

Por uma nova ordem energética global? potencialidades e perspectivas da questão energética entre os países BRICS Towards a new world energy order? potentialities and perspectives of the energy issue between the BRICS countries

Directory of Open Access Journals (Sweden)

José María Gómez

2012-12-01

Full Text Available O presente artigo propõe analisar a questão energética entre os BRICS e o potencial de rearticulação da ordem energética global que dela emerge. Para tal, realiza três movimentos. Em primeiro lugar, investiga o crescente impacto agregado dos países BRICS no cenário energético global, com vistas a analisar seu avanço em uma temática até então reduto dos países desenvolvidos. Em segundo lugar, aborda a matriz energética de cada um dos cinco países do ponto de vista de suas economias políticas e da questão da sustentabilidade. Em terceiro lugar, e com base na seção anterior, propõe mapear as áreas de conflito e de possível aproximação entre os BRICS, na tentativa de localizar as possibilidades e limites da sua cooperação energética. Com base nessa investigação, conclui que, diante das potencialidades para a cooperação entre os países, a organização de suas ofertas e demandas energéticas nacionais pode permitir ao agrupamento articular-se como um novo polo no cenário energético global.The article analyzes energy-related issues among the BRICS countries and the potential refashioning of the world energy order that might spring from them. It begins by investigating the growing impact of the BRICS countries within the international order, with the intention of tracking their progress in an ambit so far restricted to developed countries and their oil suppliers. The text subsequently analyzes the energy matrix of each of the five BRICS countries from the points of view of political economy and sustainability. Finally, based on the previous sections, the final section of the article maps the tensions and complementarities between the BRICS and outlines the possibilities and limits of their cooperation on energy issues. The analysis concludes that given the potential for energy-related cooperation between these countries, a clear definition of their national energy supply and demand may allow the grouping to position

Caracterización financiera de las empresas generadoras de energía colombianas (2005–2012

Directory of Open Access Journals (Sweden)

Amanda Lucía Restrepo Londoño

2016-01-01

Full Text Available El presente documento tiene como objetivo principal la caracterización desde el punto de vista financiero de las empresas de generación más representativas que transaron en bolsa entre los años 2005 a 2012. La generación de energía en Colombia se encuentra concentrada en cinco empresas de acuerdo con volúmenes de generación y ventas en los mercados regulado y no regulado. Estas empresas se caracterizaron a partir del análisis de indicadores financieros y correlaciones entre ellos, la demanda de energía y la entrada en operación de centrales de generación. Como resultado se evidencia la relación directa de la demanda de energía en el crecimiento de ingresos operacionales, inversiones en Propiedad, Planta y Equipo e indicadores financieros, además de una estructura financiera representada en activos fijos y financiación de largo plazo.

Conversión química y biológica de la energía luminosa fotoproducción de peroxido de hidrógeno

OpenAIRE

Roncel Gil, Mercedes

1988-01-01

Todas las formas de vida hasta ahora conocidas en nuestro planeta requieren energía para su crecimiento y conservación. Las plantas superiores y algunos tipos de algas y bacterias obtienen energía directamente de la radiación solar, que utilizan para sintetizar aquel las sustancias esenciales para su propio conocimiento y desarrollo. Los animales, en cambio, no pueden utilizar la luz solar como fuente de energía y satisfacen sus requerimientos energéticos alimentándose de plantas u otros anim...

Ahorro energético mediante estrategias de iluminación natural optimizadas

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Puigdomènech Franquesa, Joan

1986-04-01

Full Text Available Electrical charges in buildings and specially in those of commercial use, can be diminished by means of natural lighting strategies. Taking the climate features of our country into consideration, it is necessary to prevent the inconveniences caused by an en erg y excess in summer, so solar Controls are needed. The only practical way to achieve the suitable balance between thermal and light needs, so as to get a monthly or annual energetic balance optimization, is to operate with the computer. A programme with such characteristics is described here. Its application gives important sarings in non renouvable energy savings.Mediante estrategias de iluminación natural es posible disminuir las cargas eléctricas de los edificios y en especial los de uso comercial. Dadas las características climáticas de nuestro país es necesario prever los inconvenientes de un exceso de energía en verano, para lo cual es preciso disponer de controles solares. Encontrar el correcto equilibrio entre las necesidades térmicas y lumínicas en base a la optimización del balance energético mensual o anual es únicamente factible mediante el uso del ordenador. Un programa que responde a estas características es descrito en el presente trabajo, obteniéndose con su aplicación importantes ahorros en el consumo de energías no renovables.

Estrategia de control de modelo predictivo para el despacho y almacenamiento de energía renovable en sistemas híbridos

OpenAIRE

Rosero Beltrán, Jorge Luis

2012-01-01

Actualmente la energía eléctrica es generada por fuentes que consumen combustibles fósiles y/o energía nuclear, con los consecuentes riesgos y da~nos al medio ambiente que esto representa. El aumento en los precios internacionales del petróleo y su inevitable agotamiento,la demanda de grandes cantidades de energía y el envejecimiento de las redes actuales, han hecho que en los últimos años se de un importante impulso y desarrollo a la generación de electricidad basada en fuentes renovables...

Importancia energética y ambiental de la Biomasa en Colombia

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Hernández Luis Alfredo

1994-12-01

Full Text Available

Entiéndase por energía de la biomasa aquélla que se origina al procesar parcial o totalmente cualquier sustancia o materia originada a través del proceso de fotosíntesis de los vegetales. Luego comprende especies y microespecies que cumplen para el hombre y el ecosistema una función especial ligada a factores climáticos, geomorfológicos y socioeconómicos. Antes de la aparición de los combustibles fósiles (otra forma concentrada de biomasa y de la electricidad, la biomasa constituía la principal oferta energética para el desarrollo y sobrevivencia del hombre. Si se tiene en cuenta que en el proceso de alimentación humana, el hombre y los animales utilizan menos del10% de la biomasa producida, queda un sobrante en estado sólido o en suspensión y que, por sus grandes volúmenes, genera problemas de contaminación en el campo y la ciudad, por ejemplo, basuras, residuos de plazas de mercado, pulpa de café, residuos de matadero, de procesamiento de vegetales, lácteos, y licoreras, residuos domésticos y residuos animales entre otros. Para el procesamiento o aprovechamiento de estos residuos existen tecnologías que buscan incorporarlos, en términos de materia y/o energía, a los procesos energéticos y agrícolas, captando de ellos, principalmente los valiosos elementos que los originaron. Dentro de estas tecnolog

Estudio energético en el taller de chapistería en Volkswagen Navarra S.A.

OpenAIRE

Echavarren Sarasibar, Sergio

2016-01-01

El presente proyecto se ha desarrollado con el objetivo de obtener la titualción de Grado en Tecnología Indistriales de la Univerisdad Pública de Navarra. El proyecto recoge un descripción detallada de las instalaciones de aire comprimido en taller de Chapisteria, una documentación de consumos, equipos, instalaciones con el objetivo de detectar derroches energéticos en la instalación. Con dichos derroches se ha realizado medidas de ahorro que reducen el gasto energético d...

Proyecto Energético Palmdale; Decisión del Permiso Final

Science.gov (United States)

Proyecto Energético Palmdale: EPA Región 9 por el presente emite aviso de su decisión final, el cumplimiento con la Ley Federal de Aire Limpio, para la construcción de una planta generadora de electricidad de ciclo combinado y alimentada por gas natural

Estrategias pasivas de optimización energética de la vivienda social en clima mediterráneo

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Suárez, R.

2016-03-01

Full Text Available The main goals of Horizon 2020 have led to the updating of the Basic Document on Energy Saving of the Technical Building Code in 2013. The demands of the new model, based on technological and construction parameters, are associated with a more extensive assessment of the architectural conditions of buildings. This study aims to analyse the repercussion of the new regulations on Mediterranean social housing in climate zone B4. It proposes energy analysis on a basic model of a single linear block, adding different individual passive strategies relating to compactness, envelope material, solar control, solar accumulation and ventilation, analysing the improvement in energy demand, energy rating and indoor comfort. The main energy improvement actions used take into account orientation as well as the combined improvement in energy performance of the thermal envelope, ventilation rate and suitable solar protection. These lead to major reductions in energy demand and CO2 emissions while improving indoor comfort conditions.Los objetivos prioritarios del Horizonte 2020 han llevado a la actualización del Documento Básico de Ahorro de la Energía del CTE en 2013, introduciendo un nuevo modelo en las exigencias, basado en parámetros tecnológicos y constructivos, asociado a una mayor valoración de las condiciones arquitectónicas del edificio. Este trabajo pretende analizar la repercusión del nuevo marco normativo en la vivienda social del área mediterránea, en la zona climática B4. Se plantea el análisis energético en un modelo base de bloque lineal entre medianeras al que se incorporan individualmente, distintas estrategias pasivas asociadas a la compacidad, materialidad de la envolvente, control solar, acumulación solar y ventilación, analizando la mejora de la demanda de energía, la calificación energética y el confort interior. La consideración de la orientación, junto con la combinación de la mejora de las prestaciones energ

El proyecto hidroeléctrico Coca Codo Sinclair y la gobernanza energética en la Amazonía ecuatoriana

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Victor López

2013-10-01

Full Text Available Las condiciones en las que el Estado impulsa el cambio de la matriz energética, configuran problemas de gobernanza y retos para una gestión de energías renovables en la Amazonía, acorde con la Constitución y la planificación estatal del desarrollo. Coca Codo Sinclair (CCS es el mayor proyecto hidroeléctrico en implementación y apuntala las políticas de soberanía y eficiencia energética del gobierno, sin que se evidencien criterios de gestión integrada del recurso hídrico y equidad regional para las poblaciones locales.

El resurgimiento de la energía minihidráulica en España y su situación actual

OpenAIRE

Espejo Marín, Cayetano; García Marín, Ramón; Aparicio Guerrero, Ana Eulalia

2017-01-01

Las centrales minihidráulicas han sido una fuente de energía pionera para la producción de electricidad desde finales del siglo XIX. La crisis del petróleo en los años setenta del siglo XX puso de relieve la necesidad de apostar por las energías renovables, por su carácter autóctono, porque reducían la dependencia del exterior y por su menor impacto ambiental. Este artículo analiza la evolución de la energía minihidráulica en España desde mediados del siglo XX a la actualidad. El análisis del...

Spectral properties and associated plasma energization by magnetosonic waves in the Earth's magnetosphere: Particle-in-cell simulations

Science.gov (United States)

Sun, Jicheng; Gao, Xinliang; Lu, Quanming; Chen, Lunjin; Liu, Xu; Wang, Xueyi; Tao, Xin; Wang, Shui

2017-05-01

In this paper, we perform a 1-D particle-in-cell (PIC) simulation model consisting of three species, cold electrons, cold ions, and energetic ion ring, to investigate spectral structures of magnetosonic waves excited by ring distribution protons in the Earth's magnetosphere, and dynamics of charged particles during the excitation of magnetosonic waves. As the wave normal angle decreases, the spectral range of excited magnetosonic waves becomes broader with upper frequency limit extending beyond the lower hybrid resonant frequency, and the discrete spectra tends to merge into a continuous one. This dependence on wave normal angle is consistent with the linear theory. The effects of magnetosonic waves on the background cold plasma populations also vary with wave normal angle. For exactly perpendicular magnetosonic waves (parallel wave number k|| = 0), there is no energization in the parallel direction for both background cold protons and electrons due to the negligible fluctuating electric field component in the parallel direction. In contrast, the perpendicular energization of background plasmas is rather significant, where cold protons follow unmagnetized motion while cold electrons follow drift motion due to wave electric fields. For magnetosonic waves with a finite k||, there exists a nonnegligible parallel fluctuating electric field, leading to a significant and rapid energization in the parallel direction for cold electrons. These cold electrons can also be efficiently energized in the perpendicular direction due to the interaction with the magnetosonic wave fields in the perpendicular direction. However, cold protons can be only heated in the perpendicular direction, which is likely caused by the higher-order resonances with magnetosonic waves. The potential impacts of magnetosonic waves on the energization of the background cold plasmas in the Earth's inner magnetosphere are also discussed in this paper.

por energía de compactación y variación en la granulometría

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Oscar Javier Reyes Ortiz

2006-01-01

Full Text Available El objetivo de esta investigación es establecer la influencia en las propiedades dinámicas de unas mezclas asfálticas por cambios en su energía de compactación y su granulometría. Para el desarrollo de la investigación se utilizaron dos tipos de mezcla asfálticas, una mezcla cerrada (0/10 y mezcla abierta (0/20 y la variación de la energía de compactación se realizo mediante cambios en los golpes por cada cara de las briquetas en su proceso de fabricación. La investigación inició con la caracterización de los materiales granulares y el asfalto. Posteriormente se les realizó el ensayo marshall a las mezclas para determinar el porcentaje óptimo de asfalto, el cual se obtuvo de las gráficas de estabilidad, flujo y peso unitario. Finalmente, se realizaron ensayos de módulos dinámicos y ahuellamiento, para poder concluir cual es la energía de compactación óptima que debe tener la mezcla asfáltica, y así, optimizar el diseño y funcionamiento de estructuras de pavimentos flexibles con diferentes tipos de granulometría. Dentro de los resultados se resalta que el mayor módulo dinámico para la mezcla cerrada (0/10 se obtuvo para una energía de compactación de 85 golpes y para la mezcla abierta (0/20 de 75 golpes. Con respecto a la deformación permanente se obtuvo las menores deformaciones para la energía de compactación de 90 golpes en la mezcla cerrada y de 85 golpes para la granulometría abierta.

Aplicación de sistemas de gestión energética sector comercio, caso hoteles

OpenAIRE

Auladell Roig, Marc

2012-01-01

El presente proyecto se centra en la realización de auditorías energéticas aplicadas en el sector terciario, más concretamente, en los establecimientos hoteleros. La primera parte consiste en la compilación de una base teórica sobre el tema con especial atención a las guías de ahorro publicadas por los entes públicos con competencia en medidas de eficiencia energética. Con posterioridad, se traslada la gestión de los conceptos teóricos adquiridos mediante una metodología ...

O contexto atual da reabilitação energética do parque edificado em Portugal

OpenAIRE

Abreu, Maria Isabel; Oliveira, Rui; Lopes, Jorge

2012-01-01

No seu Plano de Ação para a Eficiência Energética de 2011, a Comissão Europeia refere que o parque edificado apresenta um grande potencial de poupança energética. A nova Diretiva Europeia 2010/31/EU, em processo de transposição para legislação portuguesa, veio desafiar os estados membros a tomarem medidas ainda mais ambiciosas. Concretamente, estabelece que os estados membros elaborem planos periódicos onde constem instrumentos que reduzam as barreiras existentes e encorajem os investiment...

“estudio y simulación energética del edificio de la fiec con energyplus”

OpenAIRE

Briceño Maldonado, Richard Manuel

2013-01-01

En este documento se presenta el estudio energético y análisis de cargas térmicas del edificio de la Facultad de Ingeniería en Electricidad y Computación. El objetivo principal es realizar recomendaciones para disminuir la demanda de energía eléctrica debido a la excesiva carga térmica generada por los lucernarios de policarbonato alveolar. Se analizaron varias herramientas informáticas, y mediante matriz de decisión, se escogió a la denomina EnergyPlus. Se realizaron seis comparaciones a tra...

Implementación multimedia sobre energía fotovoltaica

OpenAIRE

Álvarez Santos, Alejandro; Giménez Oró, Nèstor

2004-01-01

El presente proyecto consiste en un programa informático que explica qué es la energía fotovoltaica, qué componentes tecnológicos se utilizan para su obtención y qué cálculos previos son necesarios para realizar la implementación de un campo de paneles solares. La herramienta elegida para realizar el programa informático, ha sido Macromedia Flash MX, versión 6.

A Comparison of Fishes and Invertebrates Living in the Vicinity of Energized and Unenergized Submarine Power Cables and Natural Sea Floor off Southern California, USA

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Milton S. Love

2017-01-01

Full Text Available Increasing reliance on deep-water renewable energy has increased concerns about the effects of the electromagnetic fields (EMFs generated by submarine power cables on aquatic organisms. Off southern California, we conducted surveys of marine organisms living around energized and unenergized submarine power cables and nearby sea floor during 2012–2014 at depths between 76 and 213 m. In general, EMFs declined to background levels about one meter from the cable. We found no statistical difference in species composition between the fish assemblages along the energized and unenergized cables. The natural habitat community statistically differed from both energized and unenergized cable communities. Within species (or species groups, we found no differences in densities between energized and unenergized cables. Total fish densities were significantly higher around the cables than over the natural habitat. We found that invertebrate communities were structured by habitat type and depth and, similar to the fishes, there was no statistical difference between the energized and unenergized cables. Individually, the densities of four invertebrate species or species groups (Metridium farcimen, Luidia spp., unidentified black Crinoidea, and Urticina spp. differed between energized and unenergized cables, but this difference was not significant across all depth strata. The invertebrate community inhabiting the natural habitat strongly differed from the energized and unenergized cable community exhibiting the fewest species and individuals.

Influencia del uso ineficiente de energía eléctrica en la competitividad de las empresas textiles peruanas: 2007 - 2008

OpenAIRE

Ríos Ballesteros, Julio

2010-01-01

Objetivo: Determinar si la inadecuada elección de la opción tarifaria, el exceso de consumo de energía reactiva y la falta de análisis del comportamiento de consumo (diagrama de carga) constituyen causas de ineficiencia en el consumo de energía eléctrica. Método: Mediante un diseño explicativo experimental se analizaron las causas que originan ineficiencia en el consumo de energía eléctrica en las empresas textiles peruanas. Se seleccionó una muestra de 77 empresas del sur de la capital, que ...

Role of ions in the regulation of light-harvesting

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Radek Kana

2016-12-01

Full Text Available Regulation of photosynthetic light harvesting in the thylakoids is one of the major key factors affecting the efficiency of photosynthesis. Thylakoid membrane is negatively charged and influences both the structure and the function of the primarily photosynthetic reactions through its electrical double layer. Further, there is a heterogeneous organization of soluble ions (K+, Mg2+, Cl- attached to the thylakoid membrane that, together with fixed charges (negatively charged amino acids, lipids, provides an electrical field. The electrical double layer is affected by the valence of the ions and interferes with the regulation of state transitions, protein interactions, and excitation energy spillover from Photosystem II to Photosystem I. These effects are reflected in changes in the intensity of chlorophyll a fluorescence, which is also a measure of photoprotective non-photochemical quenching of the excited state of chlorophyll a. A triggering of non-photochemical quenching proceeds via lumen acidification and is coupled to the export of positive counter-ions (Mg2+, K+ to the stroma or/and negative ions (e.g., Cl- into the lumen. The effect of protons and anions in the lumen and of the cations (Mg2+, K+ in the stroma are, thus, functionally tightly interconnected. In this review, we discuss the consequences of the model of electrical double layer, proposed by James Barber (J. Barber (1980 Biochim Biophys Acta 594:253-308 in light of light-harvesting regulation. Further, we explain differences between electrostatic screening and neutralization, and we emphasize the opposite effect of monovalent (K+ and divalent (Mg2+ ions on light-harvesting and on screening of the negative charges on the thylakoid membrane; this effect needs to be incorporated in all future models of photosynthetic regulation by ion channels and transporters.

H+ V-ATPase-Energized Transporters in Brush Border Membrane Vesicles from Whole Larvae of Aedes Aegypti

Science.gov (United States)

Brush Border Membrane vesicles (BBMVs) from Whole larvae of Aedes aegypti (AeBBMVWs ) contain an H+ V-ATPase (V), a Na+/H+ antiporter, NHA1 (A) and a Na+-coupled, nutrient amino acid transporter, NAT8 (N), VAN for short. All V-ATPase subunits are present in the Ae. aegypti genome and in the vesicles...

Diseño de una empresa de consultoría en el área de calidad de la energía eléctrica

OpenAIRE

Hernández Barrera, Mónica

2011-01-01

Debido a la importancia actual que tiene la calidad de la energía eléctrica en las empresas del sector industrial de tamaño grande, en este trabajo de tesis de desarrolló el Diseño de una Empresa de Consultoria en el Área de Calidad de la Energía Eléctrica llamada Ingeniería y Consultoría Especializada en Monitoreo de Energía Eléctrica, ICEMEE. Los servicios de ICEMEE son:medición y monitoreo parcial de la energía y capacitación de personal. Para evaluar la factibilidad de la creación de la e...

Morteros acumuladores con parafinas microencapsuladas para el aprovechamiento de la energía solar en suelos radiantes

OpenAIRE

Zetola Vargas, Vicente Andrés

2013-01-01

Esta Tesis plantea la pregunta de si el uso de morteros con parafinas microencapsuladas combinado con colectores solares térmicos puede reducir el consumo de energías convencionales, en un sistema tradicional de suelo radiante. Se pretende contribuir al conocimiento acerca del efecto que produce en el edificio, el calor latente acumulado en suelos radiantes, utilizando morteros de cemento Portland con material de cambio de fase (PCM), en conjunto con la energía solar. Para cumplir con este pr...

Conflictos socioambientales en torno a la energía nuclear. Perspectivas desde la Investigación para la Paz

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Luis Sánchez Vázquez

2011-06-01

Full Text Available En los últimos años se ha reactivado el debate sobre la energía nuclear. Esta opción ha reemergido amparada en la etiqueta de «energía limpia», por la no emisión de gases de efecto invernadero en su proceso productivo. Sin embargo, la incertidumbre sobre las fases de tratamiento necesarias para administrar con seguridad los residuos, incluyendo, en su caso, el reprocesado del combustible; los problemas ambientales derivados de la minería del uranio; e incluso los riesgos laborales derivados del trabajo con material fisionables, componen un panorama de situaciones conflictivas de carácter complejo que continúa siendo el principal caballo de batalla de la oposición antinuclear y ecologista. En este artículo se pretenden identificar los distintos conflictos socioambientales aparejados a la energía nuclear teniendo en cuenta su ciclo de vida completo, con el objetivo aportar soluciones al debate sobre la problemática ambiental en torno a la energía nuclear desde la perspectiva de la Investigación para la Paz.

Gobernanza global y evolución de las energías renovables en el sur. Objetivos políticos y estructuras de gobernanza

OpenAIRE

Wolfgang Hein; Daniela García Sánchez; Lars Holstenkamp

2013-01-01

El desarrollo de la gobernanza global de las energías renovables comparte similitudes y diferencias con otros sectores de la gobernanza global. La proliferación de organizaciones en el sector resalta el importante compromiso de varios actores con el fomento de energías renovables y, por otro lado, produce problemas de coordinación para alcanzar un efecto óptimo e influir sobre el avance de las energías renovables, particularmente en países en desarrollo.

Análisis y propuesta de mejoras para la eficiencia energética del edificio principal del Instituto c.c. Eduardo Torroja-CSIC

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Martín-Consuegra, F.

2014-12-01

Full Text Available As part of the 80th anniversary of IETcc-CSIC, a proposal for the rehabilitation of the 1953 building is made. The analysis of the main building’s energy performance concludes that it is not energy efficient. Energy efficiency improvement measures based on European directives are proposed, It is recommended to incorporate them step by step, starting with passive measures to reduce energy needs. Afterwards active measures, such as improving the performance of facilities, are proposed, so that the least possible amount of final energy is used to meet the comfort standards. To complete the operation, the use of renewable energy sources is proposed to reduce the consumption of non-renewable primary energy. Energy and building rehabilitation improvement measures in the IETcc-CSIC should be demonstrators for other public buildings with heritage values.En el marco del 80 aniversario del IETcc-CSIC se elabora una propuesta para la rehabilitación del edificio construido en 1953. Partiendo del análisis del comportamiento energético del edificio principal, se concluye que este no es eficiente energéticamente. Se proponen mejoras para la eficiencia energética del edificio tomando en cuenta las directivas europeas. Se recomienda incorporar las mejoras de forma escalonada, comenzando por las medidas pasivas para reducir sus necesidades energéticas. A continuación se proponen medidas activas, como la mejora del rendimiento de las instalaciones, de manera que se emplee la menor cantidad posible de energía final para satisfacer el confort de los usuarios. Para completar la intervención se propone el uso de fuentes de generación de energías renovables en la parcela con el objetivo de reducir el consumo de energía primaria no renovable. Las acciones para la rehabilitación energética e integral del edificio del IETcc-CSIC, deben ser demostradoras para otros edificios públicos con valores patrimoniales.

Investigation of Prevalence of Energizer Drugs and Supplements Consumption and Effective Factors Among Bodybuilder Men in Karaj (2011)

OpenAIRE

F. Shoshtarizadeh; F. Bahramian; A.A. Safari; M. Pourghaderi; H. Barati

2013-01-01

Background: Body builder athletes’ high attention to form of body can result in high prevalence of nutritional disorders and habit to energizer drugs consumption. With notice to abuse problems of these drugs, this research was carried out to estimate prevalence of energizer drugs and supplements consumption in Karaj body builder men in 2011. Method: In cross-sectional (description- analytical) research 780 Karaj body builder men were selected randomly. Data were collected through interv...

Obtención de energía de las olas empleando materiales piezoeléctricos

OpenAIRE

González Díaz, Mario

2017-01-01

RESUMEN: En este trabajo se estimará la viabilidad de algunos sistemas, basados en el empleo de materiales piezoeléctricos, para la obtención de energía de las olas. Se calculará la energía obtenida con un modelo matemático para calcular la carga y voltaje generados en los elementos piezoeléctricos al interaccionar con las olas, teniendo en cuenta las teorías clásicas de elasticidad mecánica, la teoría lineal de Airy para las olas, el circuito eléctrico y una descripción fenomenológica del ef...

Transport of acidic amino acids by human jejunal brush-border membrane vesicles

International Nuclear Information System (INIS)

Rajendran, V.M.; Harig, J.M.; Adams, M.B.; Ramaswamy, K.

1987-01-01

This study characterizes the transport of radiolabeled acidic amino acids into brush-border membrane vesicles prepared from human jejunum. The uptakes of L-glutamic, L-aspartic, and D-aspartic acids were stimulated by a Na + gradient. Concentrative uptake (resulting in an overshoot phenomenon) of these dicarboxylic amino acids occurred when there was an outward K + gradient. In addition, increasing K + gradients resulted in enhanced uptake of L-glutamic acid. This K + requirement is somewhat specific as Rb + and Cs + could enhance uptake to a limited extent, whereas Li + and choline + showed no enhancement. The presence of a K + gradient did not affect the affinity of the carrier system for L-glutamic acid but it did increase the V/sub max/. The presence of extravesicular anions having differing membrane permeabilities did not altar L-glutamic acid uptake indicating an absence of an effect of membrane potential on the transport process. Finally, the human transport system for L-glutamic acid appears to be specific for acidic amino acids as demonstrated by inhibition studies. The studies demonstrate a transport system in human jejunum specific for acidic amino acids that is energized by an inward Na + gradient and an outward K + gradient

Fundamental processes in the expansion, energization, and coupling of single- and multi-Ion plasmas in space: Laboratory simulation experiments

Science.gov (United States)

Szuszczewicz, E. P.; Bateman, T. T.

1996-01-01

We have conducted a laboratory investigation into the physics of plasma expansions and their associated energization processes. We studied single- and multi-ion plasma processes in self-expansions, and included light and heavy ions and heavy/light mixtures to encompass the phenomenological regimes of the solar and polar winds and the AMPTE and CRRES chemical release programs. The laboratory experiments provided spatially-distributed time-dependent measurements of total plasma density, temperature, and density fluctuation power spectra with the data confirming the long-theorized electron energization process in an expanding cloud - a result that was impossible to determine in spaceborne experiments (as e.g., in the CRRES program). These results provided the missing link in previous laboratory and spaceborne programs. confirming important elements in our understanding of such solar-terrestrial processes as manifested in expanding plasmas in the solar wind (e.g., CMES) and in ionospheric outflow in plasmaspheric fluctuate refilling after a storm. The energization signatures were seen in an entire series of runs that varied the ion species (Ar', Xe', Kr' and Ne'), and correlative studies included spectral analyses of electrostatic waves collocated with the energized electron distributions. In all cases wave energies were most intense during the times in which the suprathermal populations were present, with wave intensity increasing with the intensity of the suprathermal electron population. This is consistent with theoretical expectations wherein the energization process is directly attributable to wave particle interactions. No resonance conditions were observed, in an overall framework in which the general wave characteristics were broadband with power decreasing with increasing frequency.

The use of iron charge state changes as a tracer for solar wind entry and energization within the magnetosphere

Directory of Open Access Journals (Sweden)

T. A. Fritz

Full Text Available The variation of the charge state of iron [Fe] ions is used to trace volume elements of plasma in the solar wind into the magnetosphere and to determine the time scales associated with the entry into and the action of the magnetospheric energization process working on these plasmas. On 2–3 May 1998 the Advanced Composition Explorer (ACE spacecraft located at the L1 libration point observed a series of changes to the average charge state of the element Fe in the solar wind plasma reflecting variation in the coronal temperature of their original source. Over the period of these two days the average Fe charge state was observed to vary from + 15 to + 6 both at the Polar satellite in the high latitude dayside magnetosphere and at ACE. During a period of southward IMF the observations at Polar inside the magnetosphere of the same Fe charge state were simultaneous with those at ACE delayed by the measured convection speed of the solar wind to the subsolar magnetopause. Comparing the phase space density as a function of energy at both ACE and Polar has indicated that significant energization of the plasma occurred on very rapid time scales. Energization at constant phase space density by a factor of 5 to 10 was observed over a range of energy from a few keV to about 1 MeV. For a detector with a fixed energy threshold in the range from 10 keV to a few hundred keV this observed energization will appear as a factor of ~10³ increase in its counting rate. Polar observations of very energetic O⁺ ions at the same time indicate that this energization process must be occurring in the high latitude cusp region inside the magnetosphere and that it is capable of energizing ionospheric ions at the same time.

Key words. Magnetospheric physics (magnetopause, cusp, and boundary layers; magnetospheric configuration and dynamics; solar wind-magnetosphere interactions

Test Particle Energization and the Anisotropic Effects of Dynamical MHD Turbulence

Science.gov (United States)

González, C. A.; Dmitruk, P.; Mininni, P. D.; Matthaeus, W. H.

2017-11-01

In this paper, we analyze the effect of dynamical three-dimensional magnetohydrodynamic (MHD) turbulence on test particle acceleration and compare how this evolving system affects particle energization by current sheet interaction, as opposed to frozen-in-time fields. To do this, we analyze the ensemble particle acceleration for static electromagnetic fields extracted from direct numerical simulations of the MHD equations, and compare it with the dynamical fields. We show that a reduction in particle acceleration in the dynamical model results from particle trapping in field lines, which forces the particles to be advected by the flow and suppresses long exposures to the strong electric field gradients that take place between structures and generate (among other effects) an efficient particle acceleration in the static case. In addition, we analyze the effect of anisotropy caused by the mean magnetic field. It is well known that for sufficiently strong external fields, the system experiences a transition toward a two-dimensional flow. This causes an increment in the size of the coherent structures, resulting in a magnetized state of the particles and a reduction in particle energization.

Situação Energética no Estado do Rio de Janeiro e o Capim-Elefante como Fonte Renovável

Directory of Open Access Journals (Sweden)

Antonio Alonso Cecon Novo

2016-12-01

Full Text Available Esta revisão aborda a situação energética no Estado do Rio de Janeiro e também outras fontes alternativas de energia que vêm se destacando, como por exemplo, o capim-elefante. Foi realizado um breve relato sobre as fontes para geração de energia que tiveram um papel importante para o setor energético. Dentre as principais fontes para fins energéticos, o capim-elefante tem sido muito utilizado em pesquisas pela Universidade Estadual Norte Fluminense – UENF, na obtenção de cultivares mais produtivas para o desenvolvimento econômico principalmente da região Norte e Noroeste Fluminense. Este trabalho destaca as principais fontes de energia, com ênfase para o capim-elefante na matriz energética, com a produção de biomassa para geração de energia.

D0 Central Tracking Solenoid Energization, Controls, Interlocks and Quench Protection Initial Validation Procedures

International Nuclear Information System (INIS)

Jaskierny, W.; Hance, R.

1998-01-01

This note presents the inspection and tests to be performed on the DZERO solenoid energization, controls, interlocks and quench protection system before it is energized for the first time. This test is to be performed with a 5000A jumper at the end of the bus instead of the solenoid. This system is based in DZERO room 511. A copy of this note shall be annotated, signed and dated by the person coordinating the procedure; and filed with the system maintenance records. Annotations shall include comments about any aspect of the procedure that is abnormal or unsuccessful. The following inspections and tests shall be performed by persons knowledgeable about the system. Each individual test step should be reviewed and understood before proceeding with that step.

Gobernanza global y evolución de las energías renovables en el sur. Objetivos políticos y estructuras de gobernanza

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Wolfgang Hein

2013-10-01

Full Text Available El desarrollo de la gobernanza global de las energías renovables comparte similitudes y diferencias con otros sectores de la gobernanza global. La proliferación de organizaciones en el sector resalta el importante compromiso de varios actores con el fomento de energías renovables y, por otro lado, produce problemas de coordinación para alcanzar un efecto óptimo e influir sobre el avance de las energías renovables, particularmente en países en desarrollo.

Barreras y oportunidades para el desarrollo de comunidades energéticas sostenibles en España. Estudio comparativo con Estados Unidos y Alemania

OpenAIRE

Romero Rubio, María del Carmen

2017-01-01

Las comunidades energéticas sostenibles son organizaciones en las que sus miembros se implican fuertemente para gestionar su propia energía, generarla con la máxima eficiencia y utilizar fuentes renovables. Estas comunidades aprovechan, en la medida de lo posible, los recursos locales de que disponen (energía solar, eólica, biomasa, etc.), con el fin de aumentar su autonomía y disminuir la dependencia de suministros externos. Dentro de un sistema de generación distribuida, las comunidades...

A statistical study of ion energization at 1700 km in the auroral region

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M. Hamrin

2002-12-01

Full Text Available We present a comprehensive overview of several potentially relevant causes for the oxygen energization in the auroral region. Data from the Freja satellite near 1700 km altitude are used for an unconditional statistical investigation. The data are obtained in the Northern Hemisphere during 21 months in the declining phase of the solar cycle. The importance of various wave types for the ion energization is statistically studied. We also investigate the correlation of ion heating with precipitating protons, accelerated auroral electrons, suprathermal electron bursts, the electron density variations, Kp index and solar illumination of the nearest conjugate ionosphere. We find that sufficiently strong broad-band ELF waves, electromagnetic ion cyclotron waves, and waves around the lower hybrid frequency are foremost associated with the ion heating. However, magnetosonic waves, with a sharp, lower frequency cutoff just below the proton gyrofrequency, are not found to contribute to the ion heating. In the absence of the first three wave emissions, transversely energized ions are rare. These wave types are approximately equally efficient in heating the ions, but we find that the main source for the heating is broadband ELF waves, since they are most common in the auroral region. We have also observed that the conditions for ion heating are more favourable for smaller ratios of the spectral densities SE /SB of the broadband ELF waves at the oxygen gyrofrequency.Key words. Ionosphere (auroral ionosphere; wave propogation Magnetospheric physics (electric fields

Integración de criterios de desempeños en el mejoramiento energético-ambiental de viviendas sociales existentes en Chile

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Paulina Wegertseder Martínez

Full Text Available En Chile, 75% del parque habitacional existente fue construido sin consideraciones energéticas-ambientales, convirtiéndose en altos consumidores de energía. Hoy existen medidas de mejoramiento energético para viviendas existentes, pero éstas solo consideran algunos desempeños con implicancia en la demanda energética, siendo cada uno mejorado de manera independiente, sin considerar la relación y el efecto que conllevan al estar integrados. Esta investigación propone cubrir una brecha de conocimiento, de cómo diferentes criterios de desempeños actúan integralmente en el mejoramiento energético-ambiental de una vivienda. Actualmente se carece de tal conocimiento, que bajo la filosofía prestacional, genera diversas estrategias de mejoramiento para objetivos de desempeños en climas templados: Confort Térmico, Eficiencia Energética por Calefacción y Calidad del Aire Interior. Se somete un caso de estudio en el centro-sur de Chile, a un diagnostico post-ocupacional (monitorizaciones, simulaciones dinámicas y encuestas de percepción, para establecer criterios de desempeños, cuya relevancia e interdependencia se analiza mediante un estudio multifactorial. Se concluye que para alcanzar dichos objetivos es implícito mejorar la vivienda bajo la integración de criterios como: aumento de hermeticidad al aire, disminución del valor de transmitancia térmico y entrega del caudal de ventilación mínimo; siempre en una solución holística y no aislada.

El desafío de habitar con la incorporación de energías limpias

OpenAIRE

Angiolini, Silvina; Jerez, Lisardo; Pacharoni, Ana; Ávalos, Pablo; Gatani, Mariana; Bracco, Marta

2015-01-01

En los últimos años la situación energética y los problemas de contaminación ambiental han originado una preocupación general por el uso indiscriminado de las energías no renovables en nuestros edificios. Los modos de habitar que nos llevaron a la crisis climática global hoy son replanteados en post de reducir los múltiples impactos en nuestro medio. Esto ha propiciado el impulso y desarrollo de actuaciones de investigación y desarrollo, promoción e implantación de tecnologías renovables, en ...

“estudio y simulación energético del edificio de la fiec con energyplus”

OpenAIRE

Briceño Maldonado, Richard Manuel; Peña Toro, Ph.D. Paulo

2013-01-01

En este documento se presenta el estudio energético y análisis de cargas térmicas del edificio de la Facultad de Ingeniería Eléctrica y Computación. El objetivo principal es realizar recomendaciones para disminuir la demanda de energía eléctrica debido a la excesiva carga térmica generada por los lucernarios de policarbonato alveolar. Se analizaron varias herramientas informáticas, y mediante matriz de decisión, se escogió a la denomina EnergyPlus. Se realizaron seis comparaciones a través de...

Proyecto Arquitectónico Energéticamente Eficiente Mediante Gramáticas de Formas y Aprendizaje por Refuerzo

OpenAIRE

Gavilanes-Velaz-de-Medrano, Juan; Hidalgo, Pablo; Belmonte, David; Mandow-Andaluz, Lorenzo; Ruiz-Montiel, Manuela

2015-01-01

En este trabajo presentamos un sistema para la generación de esquemas de viviendas unifamiliares energéticamente eficientes. Los esquemas se sintetizan mediante la ejecución de gramáticas de formas simples, entrenadas por medio de técnicas de aprendizaje por refuerzo, teniendo en cuenta criterios tanto de habitabilidad como de eficiencia energética. Los resultados obtenidos son analizados y validados Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.

Gestión Óptima de la Energía en Microrredes con Generación Renovable

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Carlos Bordons

2015-04-01

Full Text Available Resumen: Este artículo se centra en los temas relacionados con la operación óptima de las microrredes, que son conjuntos de cargas, generadores y sistemas de almacenamiento de energía, aislados o conectados al resto de la red eléctrica, que pueden ser gestionados de manera coordinada para suministrar electricidad de forma fiable. Se aborda la problemática y las soluciones de control tanto para la gestión del reparto de la carga entre los distintos generadores y almacenamiento como para la integración de la microrred en el mercado eléctrico. Se presentan diseños de controladores en el marco del Control Predictivo Basado en Modelo (Model Predictive Control, MPC para casos que incluyen diversas fuentes renovables, como energía solar y eólica, y almacenamiento híbrido con hidrógeno, lo que permite gestionar el balance de energía en distintas escalas de tiempo. Se muestran algunos resultados experimentales en una microrred de laboratorio así como estudios de planificación para el mercado eléctrico. Los resultados obtenidos indican que el desarrollo de controladores adecuados facilitará una participación competitiva de las energías renovables y la integración de las microrredes en el nuevo modelo de sistema eléctrico. Abstract: This paper deals with some issues related to optimal operation of microgrids, which are a group of loads, generators and energy storage systems that can be managed isolated or connected to the main grid, in a coordinated way in order to reliably supply electricity. The control problems and solution are addressed both for optimal dispatch and for the integration of the microgrid in the electricity market. Development of Model Predictive Controllers are presented for case studies that include several renewable sources (photovoltaic and wind as well as hybrid storage using hydrogen. Some experimental results for a demonstration microgrid are presented, as well as simulations of scheduling in the electricity

Isolation of Highly Purified Fractions of Plasma Membrane and Tonoplast from the Same Homogenate of Soybean Hypocotyls by Free-Flow Electrophoresis 1

Science.gov (United States)

Sandelius, Anna Stina; Penel, Claude; Auderset, Guy; Brightman, Andrew; Millard, Merle; Morré, D. James

1986-01-01

A procedure is described whereby highly purified fractions of plasma membrane and tonoplast were isolated from hypocotyls of dark-grown soybean (Glycine max L. var Wayne) by the technique of preparative free-flow electrophoresis. Fractions migrating the slowest toward the anode were enriched in thick (10 nanometers) membranes identified as plasma membranes based on ability to bind N-1-naphthylphthalamic acid (NPA), glucan synthetase-II, and K+-stimulated, vanadate-inhibited Mg2+ ATPase, reaction with phosphotungstic acid at low pH on electron microscope sections, and morphological evaluations. Fractions migrating farthest toward the anode (farthest from the point of sample injection) were enriched in membrane vesicles with thick (7-9 nanometers) membranes that did not stain with phosphotungstic acid at low pH, contained a nitrate-inhibited, Cl-stimulated ATPase and had the in situ morphological characteristics of tonoplast including the presence of flocculent contents. These vesicles neither bound NPA nor contained levels of glucan synthetase II above background. Other membranous cell components such as dictyosomes (fucosyltransferase, latent nucleosidediphosphate phosphatase), endoplasmic reticulum vesicles (NADH- and NADPH- cytochrome c reductase), mitochondria (succinate-2(p-indophenyl)-3-p-nitrophenyl)-5-phenyl tetrazolium-reductase and cytochrome oxidase) and plastids (carotenoids and monogalactosyl diglyceride synthetase) were identified on the basis of appropriate marker constituents and, except for plastid thylakoids, had thin (marker activities. From electron microscope morphometry (using both membrane measurements and staining with phosphotungstic acid at low pH) and analysis of marker enzymes, both plasma membrane and tonoplast fractions were estimated to be about 90% pure. Neither fraction appeared to be contaminated by the other by more than 3%. Images Fig. 1 Fig. 3 Fig. 4 Fig. 5 Fig. 9 PMID:16664771

Los ciudadanos castellano-manchegos y el uso de la energía: medio rural versus medio urbano

OpenAIRE

Colmenero Herreros, Isabel

2016-01-01

El objetivo principal de esta tesis es indagar en los comportamientos de uso energético de la ciudadanía castellano-manchega comparativamente entre el medio rural y urbano, considerando, por un lado, las características sociales de los individuos, sus perfiles, y por otro diferenciar los hábitos energéticamente eficientes y los ineficientes, y su evolución en el tiempo. Se profundiza en un tema novedoso y de futuro en España: no solo constituye el primer estudio que indaga en este tema, sino...

Análisis de discursos ideológicos en la empresa: La deslegitimación y la defensa de las energías renovables

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Esperanza Morales-López

2012-09-01

Full Text Available En este trabajo se analizan discursos del ámbito empresarial en los que se defienden propuestas ideológicas en el tema económico; en concreto, se analizan varios discursos en los que la Asociación Española de Productores de Energías Renovables (APPA, en adelante responde a las críticas vertidas desde determinadas multinacionales del sector de la energía por las subvenciones públicas otorgadas a las empresas de energías renovables, en particular a los productores de energía fotovoltaica. Los resultados del análisis (pragmático-discursivo y argumentativo revelan que el recurso principal que utiliza APPA para la defensa de este tipo de energías es la recontextualización de las críticas recibidas por parte de las multinacionales del sector de la energía, transformando estas críticas en una macroestrategia de deslegitimación de las energías renovables por parte de estas multinacionales. En el conjunto de los discursos analizados y del resto de estrategias argumentativas utilizadas, se puede observar, además, cómo esta deslegitimación es utilizada por APPA como prueba argumentativo-persuasiva para mostrar lo absurdo de tales críticas. Desde la perspectiva teórico-metodológica, este trabajo muestra la importancia en estos discursos de los recursos retóricoselocutivos; es decir, de aquellos capaces de activar marcos cognitivos determinados que evocan emociones, porque tanto transmiten intenciones como mueven a la acción. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1203209

Radiation signatures from a locally energized flaring loop

Science.gov (United States)

Emslie, A. G.; Vlahos, L.

1980-01-01

The radiation signatures from a locally energized solar flare loop based on the physical properties of the energy release mechanisms were consistent with hard X-ray, microwave, and EUV observations for plausible source parameters. It was found that a suprathermal tail of high energy electrons is produced by the primary energy release, and that the number of energetic charged particles ejected into the interplanetary medium in the model is consistent with observations. The radiation signature model predicts that the intrinsic polarization of the hard X-ray burst should increase over the photon energy range of 20 to 100 keV.

Diagnóstico de qualidade e balanço energético na produção de pupunheira em propriedades familiares na região do Caparaó.

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Bruno Fardim Christo

2014-04-01

Full Text Available Estudos que apontem o fluxo energético dos sistemas de cultivo são de grande importância para a produção agrícola a fim de atingir uma agricultura mais sustentável. O objetivo deste trabalho foi caracterizar a eficiência energética na produção de palmito de pupunha através do balanço energético do sistema e de indicadores de qualidade, em duas propriedades familiares no município de Alegre/ES. Foram adotadas metodologias participativas para promover maior interação com o agricultor e sua família, e consequentemente obter maior volume de informações para a coleta de dados. O balanço energético foi realizado pela diferença entre os gastos energéticos (entrada e a produção alcançada (saída. A propriedade 1 apresentou balanço energético positivo e superiores indicadores de qualidade, já a propriedade 2 apresentou balanço energético negativo e inferiores diagnóstico de qualidade. A propriedade 1 apresentou maior eficiência energética mostrando estar usando melhor os seus recursos na produção da pupunheira.

Caracteriza??es f?sica e qu?mica de res?duos s?lidos da cajucultura e avalia??o do potencial energ?tico em processos de convers?o t?rmica

OpenAIRE

Tavares, Priscilla Torquato

2016-01-01

O aumento da demanda energ?tica e a crescente necessidade de produ??o sustent?vel de energia tem mostrado a import?ncia da diversifica??o das fontes energ?ticas. A biomassa tem se destacado por suas caracter?sticas econ?micas, f?sicas e qu?micas, podendo ser considerada como a fonte energ?tica do futuro. Os res?duos agr?colas s?o uma forma de biomassa apropriada para produ??o energ?tica. A gera??o de res?duos proveniente do cultivo e beneficiamento do caju produziu em 2015, no ...

Análisis técnico económico preliminar para generar electricidad con energía renovable // Preliminary technical economic analysis to generate electricity with renewable energy

OpenAIRE

M. Menéndez González

2000-01-01

Dentro de las posibilidades energéticas y medioambientales de los distintos tipos de energías renovables; la eólica por sucarácter limpio e inagotable, permite un gran desarrollo en aquellas áreas que cuentan con el potencial necesario para suaplicación y de forma similar, la energía solar presenta ventajas importantes, ambas son recursos gratuitos, nocontaminantes y disponibles en muchas localidades. Según las tecnologías actualmente disponibles, la utilización desistemas híbridos de energía...

Adiabatic energization in the ring current and its relation to other source and loss terms

Science.gov (United States)

Liemohn, M. W.; Kozyra, J. U.; Clauer, C. R.; Khazanov, G. V.; Thomsen, M. F.

2002-04-01

The influence of adiabatic energization and deenergization effects, caused by particle drift in radial distance, on ring current growth rates and loss lifetimes is investigated. Growth and loss rates from simulation results of four storms (5 June 1991, 15 May 1997, 19 October 1998, and 25 September 1998) are examined and compared against the y component of the solar wind electric field (Ey,sw). Energy change rates with and without the inclusion of adiabatic energy changes are considered to isolate the influence of this mechanism in governing changes of ring current strength. It is found that the influence of adiabatic drift effects on the energy change rates is very large when energization and deenergization are considered separately as gain and loss mechanisms, often about an order of magnitude larger than all other source or loss terms combined. This is true not only during storm times, when the open drift path configuration of the hot ions dominates the physics of the ring current, but also during quiet times, when the small oscillation in L of the closed trajectories creates a large source and loss of energy each drift orbit. However, the net energy change from adiabatic drift is often smaller than other source and loss processes, especially during quiet times. Energization from adiabatic drift dominates ring current growth only during portions of the main phase of storms. Furthermore, the net-adiabatic energization is often positive, because some particles are lost in the inner magnetosphere before they can adiabatically deenergize. It is shown that the inclusion of only this net-adiabatic drift effect in the total source rate or loss lifetime (depending on the sign of the net-adiabatic energization) best matches the observed source and loss values from empirical Dst predictor methods (that is, for consistency, these values should be compared between the calculation methods). While adiabatic deenergization dominates the loss timescales for all Ey,sw values

Elección de criterios y valoración de impactos ambientales para la implantación de energía eólica

OpenAIRE

Molina Ruiz, José; Tudela Serrano, María Luz

2008-01-01

La energía eólica es una energía limpia y renovable y los beneficios que comporta un Parque Eólico son mayores que los inconvenientes. Emplazamientos idóneos, reducción de impactos ambientales, conservación de los valores naturales y paisajísticos del entorno y las necesidades socioeconómicas de la zona se suman a un uso racional de esta energía y un desarrollo tecnológico paralelo para alcanzar un desarrollo sostenible.

Diretrizes para inserção de requisitos de eficiência energética no processo de projeto de aeroportos

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Fernanda Selistre da Silva Scheidt

Full Text Available Este artigo aborda a gestão de informação na etapa de projeto visando à consideração de requisitos de eficiência energética em projetos de obras complexas, relatando um estudo de caso em projeto de aeroportos. O atendimento aos requisitos de eficiência energética tende a aumentar ainda mais a complexidade do processo de desenvolvimento do produto (PDP na construção civil. Torna-se necessário, então, buscar instrumentos gerenciais que auxiliem o projetista a analisar as restrições e tradeoffs no PDP ao mesmo tempo em que se considere a agregação de mais valor ao produto, tanto sob o ponto de vista do cliente como do meio ambiente. A decisão de analisar o processo de projeto de aeroportos surgiu pelo fato de essas edificações serem caracterizadas pela complexidade e por apresentarem alto consumo energético e grande impacto ambiental. A partir de uma etapa de revisão bibliográfica, foram identificados os requisitos de eficiência energética a serem considerados na prática de projeto. O estudo teve sequência com a elaboração do macromapeamento do PDP, em um estudo de caso. Os resultados alcançados consistem na análise crítica do PDP e na identificação de oportunidades de inserção dos requisitos de eficiência energética no processo de projeto aeroportuário, considerando as falhas no fluxo de informação entre os agentes envolvidos. Por fim, são apresentadas diretrizes para a inserção dos requisitos de eficiência energética identificados a partir da revisão bibliográfica no processo de projetos de aeroportos.

Otimização energética de sistemas de arejamento e agitação

OpenAIRE

Feliciano, Nicole Danielle Manteigas

2014-01-01

Este estágio foi desenvolvido na Águas do Oeste, no período compreendido entre outubro de 2013 e julho de 2014, tendo como objetivo a otimização energética dos sistemas de arejamento e agitação. A importância deste tema deve-se ao fato de estes sistemas serem responsáveis por cerca de 70% do consumo de uma ETAR. Identificaram-se possíveis equipamentos a intervencionar e através de pesquisa bibliográfica e consulta de experts possíveis soluções em termos de eficiência energética, sendo apre...

Effectiveness of the Energize Elementary School Program to Improve Diet and Exercise

Science.gov (United States)

Herbert, Patrick C.; Lohrmann, David K.; Seo, Dong-Chul; Stright, Anne D.; Kolbe, Lloyd J.

2013-01-01

Background: The rate of childhood obesity has more than tripled during the past 30?years. Research shows that prevention at an early age is more effective than treatment later in life. Energize is a multicomponent intervention incorporated into the school day that combines nutrition education and physical activity aimed at maintaining healthy…

Understanding Free Radicals: Isolating Active Thylakoid Membranes and Purifying the Cytochrome b6f Complex for Superoxide Generation Studies

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Jason Stofleth

2012-01-01

Full Text Available All life persists in an environment that is rich in molecular oxygen. The production of oxygen free radicals, or superoxide, is a necessary consequence of the biogenesis of energy in cells. Both mitochondrial and photosynthetic electron transport chains have been found to produce superoxide associated with cell differentiation, proliferation, and cell death, thereby contributing to the effects of aging. Aerobic respiration in mitochondria consumes oxygen, whereas photosynthesis in chloroplasts or cyanobacteria produces oxygen. The increased concentration of molecular oxygen may serve to allow greater availability for the production of superoxide by cytochrome bc complexes in photosynthetic membranes compared to those of mitochondrial membranes. The isolation of well-coupled chloroplasts, containing the cytochrome b6f complex of oxygenic photosynthesis, is a vital initial step in the process of comparing the rate of production of superoxide to those of the homologous cytochrome bc1 complex of aerobic respiration. It is necessary to determine if the isolated chloroplasts have retained their oxygengenerating capability after isolation by an oxygen evolution assay with a Clark-type electrode. A necessary second step, which is the isolation of cytochrome b6f from spinach, has yet to be successfully performed. Oxygen measurements taken from chloroplasts in the presence of the uncoupler, NH4Cl, exhibited a rate of oxygen evolution over three times greater at 344 +/- 18 μmol O2/mg Chlorophyll a/hr than the rate of oxygen evolution without uncoupler at 109 +/- 29 μmol O2/mg Chlorophyll a/hr. These data demonstrate that the technique used to isolate spinach chloroplasts preserves their light-driven electron-transport activity, making them reliable for future superoxide assays.

El análisis de flujos energéticos como herramienta de análisis territorial; el caso de la Región Metropolitana de Barcelona

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María Christina Fragkou

2015-12-01

Full Text Available La diversificación de las fuentes energéticas usadas a lo largo de la historia, resultado del creciente consumo de los sistemas socioeconómicos, ha sido un factor clave tanto en determinar nuestra relación con el medio ambiente, como en la evolución de la economía global y el ordenamiento territorial a todas las escalas geográficas. Una gran mayoría de los estudios relacionados se ha enfocado en el análisis del consumo energético urbano y de los factores que lo condicionan. Este artículo presenta un marco metodológico basado en el concepto de metabolismo energético para el análisis de sistemas urbano-regionales. La metodología se aplica a un sistema costero del Mediterráneo. Los resultados demuestran que el estudio de los flujos energéticos es una herramienta valiosa para la interpretación de la estructura económica de un sistema y la evaluación de su autosuficiencia energética. Adicionalmente, es capaz de revelar posibles patrones de consumo energético asociados a distintos tipos de economías y de urbanización.

Balanço energético da produção de grãos, carne e biocombustíveis em sistemas especializados e mistos

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Jerusa Maia e Sá

2013-10-01

Full Text Available O objetivo deste trabalho foi avaliar a eficiência energética de sistemas especializados e mistos de produção de grãos e carne e o balanço energético na produção de bioenergia. Foram avaliados dados de 20 anos de cultivo com sistemas agrícolas especializados e mistos. Como sistemas agrícolas especializados, avaliaram-se: a pastagem de gramínea; a pastagem de gramínea consorciada com leguminosa; e a produção de grãos em sistema plantio direto ou em sistema convencional de preparo do solo. Como sistema misto, considerou-se a integração lavoura-pecuária em dois sistemas de manejo. Os insumos utilizados foram considerados como o ingresso energético, enquanto a produção de grãos e carne, as saídas de energia. Os produtos agrícolas nos sistemas mistos apresentaram balanço energético e produção absoluta de energia renovável compatíveis com aqueles produzidos em sistemas especializados. O balanço energético do biocombustível de soja apresentou valores positivos tanto em sistemas mistos como especializados, independentemente do sistema de preparo do solo. Entre os biocombustíveis de soja e milho analisados, o maior balanço energético foi observado no bioetanol produzido com milho. Os biocombustíveis produzidos em todos os sistemas apresentam balanço energético positivo e podem ser considerados energeticamente sustentáveis.

Modelo de simulación del consumo de energía eléctrica doméstica

OpenAIRE

Les Aguerrea, Íñigo

2015-01-01

El objetivo de este proyecto fin de carrera es el desarrollo de un modelo de simulación del consumo de energía eléctrica en el hogar que sirva como herramienta para despertar un pensamiento crítico sobre sostenibilidad y uso eficiente de la energía. Para ello se ha prestado especial atención en crear un modelo de simulación que permita la incorporación interactiva de decisiones por parte del usuario y que muestre las consecuencias de tales decisiones. De esta forma, se ha focalizado en dotar ...

Análisis económico y financiero de las empresas cotizadas pertenecientes al sector de las energías renovables

OpenAIRE

Rodríguez Regueiro, Luis Manuel

2012-01-01

Situados en este contexto, el objetivo de este Trabajo Fin de Master es ofrecer una visión del sector de las energías renovables, mediante el estudio de sus características y su funcionamiento, y analizar la situación económica y financiera que presentan las empresas cotizadas pertenecientes al sector de las energías renovables.

Ultrastructural study on dynamics of lipid bodies and plastids during ripening of chili pepper fruits.

Science.gov (United States)

Liu, Lin

2013-03-01

Dynamics of lipid bodies and plastids in chili pepper fruits during ripening were investigated by means of transmission electron microscopy. Mesocarp of chili pepper fruits consists of collenchyma, normal parenchyma, and huge celled parenchyma. In mature green fruits, plastids contain numerous thylakoids that are well organized into grana in collenchyma, a strikingly huge amount of starch and irregularly organized thylakoids in normal parenchyma, and simple tubes rather than thylakoids in huge celled parenchyma. These morphological features suggest that plastids are chloroplasts in collenchyma, chloroamyloplasts in normal parenchyma, proplastids in huge celled parenchyma. As fruits ripen to red, plastids in all cell types convert to chromoplasts and, concomitantly, lipid bodies accumulate in both cytoplasm and chromoplasts. Cytosolic lipid bodies are lined up in a regular layer adjacent to plasma membrane. The cytosolic lipid body consists of a core surrounded by a membrane. The core is comprised of a more electron-dense central part enclosed by a slightly less electron-dense peripheral layer. Plastidial lipid bodies in collenchyma, normal parenchyma, and endodermis initiate as plastoglobuli, which in turn convert to rod-like structures. Therefore, plastidial lipid bodies are more dynamic than cytosolic lipid bodies. Both cytosolic and plastidial lipid bodies contain rich unsaturated lipids. Copyright © 2012 Elsevier Ltd. All rights reserved.

Tendencias de Tarificación en el Suministro de Energía Eléctrica

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Hernando Durán Castro

2015-03-01

Full Text Available Se presenta un modelo de precios de energía eléctrica que permite a productores y consumidores operar como mercado. La demanda de energía eléctrica es variable en el tiempo y no es almacenable de un período a otro: se genera en el momento en que se demanda. Las tecnologías de generación (hidráulica, nuclear, térmica, etc. utilizan distintos combustibles y tienen costos diferentes de inversión en capacidad y de operación. El modelo minimiza la suma de ambos costos y garantiza que los productores obtengan un beneficio sobre la inversión en capacidad igual al WACC (Weighted Average Cost of Capital.

Response of the photosynthetic system to altered protein composition and changes in environmental conditions

NARCIS (Netherlands)

Tóth, T.

2014-01-01

The photosynthetic thylakoid membrane has a hierarchically ordered structure containing pigment-protein complexes that capture solar radiation and convert it into chemical energy. Its highly dynamic structure is capable to continuously respond to the altered environmental conditions, e.g., light

Cyanobacterial photosystem II at 2.9-A resolution and the role of quinones, lipids, channels and chloride

NARCIS (Netherlands)

Guskov, Albert; Kern, Jan; Gabdulkhakov, Azat; Broser, Matthias; Zouni, Athina; Saenger, Wolfram

Photosystem II (PSII) is a large homodimeric protein-cofactor complex located in the photosynthetic thylakoid membrane that acts as light-driven water:plastoquinone oxidoreductase. The crystal structure of PSII from Thermosynechococcus elongatus at 2.9-A resolution allowed the unambiguous assignment

Mechanisms of energy transfer and conversion in plant Light-Harvesting Complex II

Energy Technology Data Exchange (ETDEWEB)

Barros, Tiago Ferreira de

2009-09-24

The light-harvesting complex of photosystem II (LHC-II) is the major antenna complex in plant photosynthesis. It accounts for roughly 30% of the total protein in plant chloroplasts, which makes it arguably the most abundant membrane protein on Earth, and binds about half of plant chlorophyll (Chl). The complex assembles as a trimer in the thylakoid membrane and binds a total of 54 pigment molecules, including 24 Chl a, 18 Chl b, 6 lutein (Lut), 3 neoxanthin (Neo) and 3 violaxanthin (Vio). LHC-II has five key roles in plant photosynthesis. It: (1) harvests sunlight and transmits excitation energy to the reaction centres of photosystems II and I, (2) regulates the amount of excitation energy reaching each of the two photosystems, (3) has a structural role in the architecture of the photosynthetic supercomplexes, (4) contributes to the tight appression of thylakoid membranes in chloroplast grana, and (5) protects the photosynthetic apparatus from photo damage by non photochemical quenching (NPQ). A major fraction of NPQ is accounted for its energy-dependent component qE. Despite being critical for plant survival and having been studied for decades, the exact details of how excess absorbed light energy is dissipated under qE conditions remain enigmatic. Today it is accepted that qE is regulated by the magnitude of the pH gradient ({delta}pH) across the thylakoid membrane. It is also well documented that the drop in pH in the thylakoid lumen during high-light conditions activates the enzyme violaxanthin de-epoxidase (VDE), which converts the carotenoid Vio into zeaxanthin (Zea) as part of the xanthophyll cycle. Additionally, studies with Arabidopsis mutants revealed that the photosystem II subunit PsbS is necessary for qE. How these physiological responses switch LHC-II from the active, energy transmitting to the quenched, energy-dissipating state, in which the solar energy is not transmitted to the photosystems but instead dissipated as heat, remains unclear and is the

Costa Rica: Hydroelectric utility Energía Global finances upstream reforestation

OpenAIRE

Energía Global (Global Energy S.A.); The National Forest Office; National Fund for Forest Financing (FONAFIFO)

2006-01-01

Metadata only record The goal of Energía Global is to increase both the stream flow and decrease sedimentation in the hydroelectric reservoirs. They are attempting to do this by reforestation projects as well as forest conservation. The sources of revenue for this project are from the private hydroelectric company and the government through taxes on fossil fuels. PES-1 (Payments for Environmental Services Associate Award)

Implicaciones medioambientales y socioeconómicas de las energías renovables

Directory of Open Access Journals (Sweden)

Carlos J. Pardo Abad

2001-06-01

Full Text Available El impacto de la energía sobre el medio ambiente es profundo y cada vez más complicado de resolver. Los problemas afectan a distintas escalas geográficas y demandan la participación más activa de las energías renovables. Los beneficios no sólo son medioambientales sino también económicos y sociales: reducción de emisiones contaminantes a la atmósfera, creación de empleo, impulso tecnológico, incremento de la competitividad industrial, modernización y desarrollo de recursos propios en áreas rurales, etc.The impact of energy on environment is deep and it is becoming more and more complicated to resolve. The problems affect several geographical scales and require a more active participation of renewable energies. Benefits are not only environmental, but also economic and social: reduction of pollutant emissions to atmosphere, creation of newjobs, technological boost, increase of the industrial competitiveness, modernization and development of own resources in country áreas, etc.

Energize New York -- Residential Energy Efficiency Market Transformation in New York

Energy Technology Data Exchange (ETDEWEB)

Bregman, Thomas M.

2013-12-31

Energize New York (ENY) is focused on addressing known barriers to widespread energy efficiency (EE) adoption by property owners. In simple terms ENY works to; 1) increase homeowner trust by using known and trusted community leaders to communicate their own positive experiences with EE and ENY, 2) reduce friction points by integrating support staff and creative use of technology that ease a homeowner’s way forward through the EE upgrade process, 3) increase homeowner knowledge and trust of specific EE benefits through access to the ENY energy coach, 4) provide information on available financing options that show benefits (e.g. positive cash flow), and 5) provide tools and mechanisms that give homeowners greater comfort in evaluating and selecting the right contractor. These five fundamental program aspects are supported by a hyper-local communications and outreach model and a “lead by example” philosophy that requires community leaders to step forward and model energy efficiency behavior by example. In the communities where the program has successfully engaged local leadership and “trusted community sources” there has been a significant increase in the uptake of energy efficiency work. Quantitatively this growth translated into an increase of 240% in completed Home Performance projects from the two year pre-pilot period (2009-10) to the two year post-pilot period (2012-13). Additionally, the program has seen measureable increases in the output and performance of contractors who are members of the Energize Comfort Corps, a program innovation which included a subset of the NYSERDA approved and Building Performance Institute accredited home performance contractors. This innovation, launched in the later stages of the pilot, is paired with the Energize Contractor Ratings Index (CRI) and helps frame the provider market by giving homeowners a mechanism to provide and receive feedback on their contractor experience. The data incorporated into the CRI along with

La conservación de la energía: un principio de toda la física. Una propuesta y unos resultados

OpenAIRE

Solbes Matarredona, Jordi; Tarín, Francisco

2004-01-01

Resumen. La conservación de la energía es uno de los conceptos más importantes de la física porque unifi ca todos los fenómenos. En este artículo presentamos algunos resultados de una investigación sobre el proceso de enseñanza-aprendizaje del concepto de energía y su conservación realizado en el nivel de la educación secundaria española. El análisis de los datos pone de manifiesto que la conservación de la energía se introduce en mecánica y termodinámica pero no en todos los campos de la fís...

La conservación de la energía : un principio de toda la física : una propuesta y unos resultados

OpenAIRE

Solbes Matarredona, Jordi

2004-01-01

La conservación de la energía es uno de los conceptos más importantes de la física porque unifica todos los fenómenos. En este artículo presentamos algunos resultados de una investigación sobre el proceso de enseñanza-aprendizaje del concepto de energía y su conservación realizado en el nivel de la educación secundaria española. El análisis de los datos pone de manifiesto que la conservación de la energía se introduce en mecánica y termodinámica pero no en todos los campos de la física. Los r...

Papel de la leptina como señal aferente en la regulación de la homeostasis energética

Directory of Open Access Journals (Sweden)

José María Basain Valdés

Full Text Available La obesidad es una enfermedad crónica caracterizada por un aumento patológico de grasa corporal generado por un desbalance entre los ingresos y los egresos energéticos; este exceso de energía se almacena en el tejido adiposo, el cual no solo almacena lípidos, sino que secreta numerosas hormonas, por lo que constituye el órgano endocrino de mayor tamaño del organismo. A diferencia de otras glándulas endocrinas, su masa es variable y puede aumentar o disminuir progresivamente de tamaño dependiendo de la edad, la ingesta alimentaria, la actividad física, la programación perinatal y la predisposición genética; se destaca dentro de los factores secretados la leptina, la cual participa en la regulación del balance energético y la secreción de gonadotropinas.El objetivo de la presente revisión bibliográfica es describir el papel de la leptina como señal aferente en la regulación de la homeostasis energética, y se destaca su importancia como uno de los mecanismos implicados en la patogénesis de la obesidad.

Evaluación a través del presupuesto de la energía incorporada al proyecto de edificación

Directory of Open Access Journals (Sweden)

Antonio Freire Guerrero

2015-06-01

Full Text Available Conocido es el alto impacto ambiental que tiene la construcción de edificios. Para poder tomar decisiones que lo disminuyan este debe ser cuantificado desde la etapa de diseño por lo que es necesario contar con herramientas sencillas de implementar. En el sector son empleadas de forma generalizada las bases de costes, las que se presentan como vehículo de incorporación del impacto ambiental. Se utiliza el caso particular de la Base de Costes de la Construcción de Andalucía (BCCA para demostrar, de forma estructurada, la incorporación de los costes energéticos (energía incorporada en los presupuestos de los proyectos. De forma novedosa se propone también incluir los costes energéticos del alimento de los trabajadores durante su jornada laboral y su movilidad, los que pueden llegar a representar desde un 5% a un 20% del total. Por último, se evalúa la energía incorporada en los costes indirectos de la obra que pueden ser significativos y que suelen ser obviados en los análisis.

Cálculo del ahorro de energía por menor fricción

Directory of Open Access Journals (Sweden)

Pedro Albarracín Aguillón

2004-01-01

Full Text Available En este artículo se expone como disminuir costos de operación (menor consumo de energía, costos de mantenimiento y pérdidas de producción de equipos, mediante el control de los diferentes fenómenos de la fricción en mecanismos lubricados. Para hacer esto posible es necesario conocer las condiciones criticas de trabajo de los mismos, a que tipo de lubricación corresponden, y que clase lubricante requiere, para así calcular los valores de los coeficientes de fricción de los lubricantes que se están empleando y compararlos con los de otros lubricantes que pueden dar lugar a ahorros de energía y mantenimiento. Además se presentan algunos ejemplos tomados de casos reales, que confirman que con una buena implementación de un programa de tribologia se obtienen resultados satisfactorios desde el punto de vista económico.

Estudio de la eficiencia energética en el sector residencial ecuatoriano y definición de propuestas de mejora desde el ámbito normativo

OpenAIRE

Ortega Zuñiga, María Luisa

2017-01-01

El trabajo de tesis consiste en el estudio de la eficiencia energética en el sector residencial ecuatoriano y la definición de propuestas de mejora desde el ámbito normativo. Los efectos del crecimiento insostenible de la demanda energética que causa al medio ambiente genera la necesidad de tomar conciencia y acciones que minimicen su consumo. El trabajo Final de Master, está enfocado a analizar parte de estas causas, relacionadas con el consumo energético del sector residencial en Ecuador...

Estimación de la huella energética en agroecosistemas cultivados con vid y ajo en Mendoza, Argentina

OpenAIRE

Santoni, Leonardo; Hidalgo, Verónica P.; Filippini, María Flavia; Gennari, Alejandro J.

2015-01-01

A nivel mundial, los cultivos de mayor importancia como maíz, trigo, soja y girasol presentan una huella energétic aconocida. En Mendoza, Argentina, aún no han sido estudiados los principales cultivos de importancia socio-económica para la región, como la vid (Vitis vinifera L.), especie perenne y el ajo (Allium sativum L.), especie anual, manejados en agroecosistemas convencionales. La presencia de indicadores energéticos como Eficiencia (EE), Balance (BE) y Productividad (PE), permiten obte...

Functions of tocopherols in the cells of plants and other photosynthetic organisms.

Science.gov (United States)

Mokrosnop, V M

2014-01-01

Tocopherol synthesis has only been observed in photosynthetic organisms (plants, algae and some cyanobacteria). Tocopherol is synthesized in the inner membrane of chloroplasts and distributed between chloroplast membranes, thylakoids and plastoglobules. Physiological significance of tocopherols for human and animal is well-studied, but relatively little is known about their function in plant organisms. Among the best characterized functions oftocopherols in cells is their ability to scavenge and quench reactive oxygen species and fat-soluble by-products of oxidative stress. There are the data on the participation of different mechanisms of α-tocopherol action in protecting photosystem II (PS II) from photoinhibition both by deactivation of singlet oxygen produced by PSII and by reduction of proton permeability of thylakoid membranes, leading to acidification of lumen under high light conditions and activation of violaxanthin de-epoxidase. Additional biological activity of tocopherols, independent of its antioxidant functions have been demonstrated. Basic mechanisms for these effects are connected with the modulation of signal transduction pathways by specific tocopherols and, in some instances, by transcriptional activation of gene expression.

Análisis descriptivo de la evolución de los modelos tecnológicos difundidos en el Distrito Zavalla (Santa Fe desde una perspectiva energética

Directory of Open Access Journals (Sweden)

Julio Denoia

2006-01-01

Full Text Available En la evolución socio-económica y tecnológica de los agroecosistemas de la región pampeana en los últimos 30 años pueden diferenciarse tres modelos productivos: el de agriculturización, el de siembra directa y de variedades de soja transgénicas (gen RR y el actual, con cultivos de alto potencial de rendimiento, consolidación del sistema de siembra directa y empleo creciente de insumos. Estos modelos introdujeron modificaciones en los agroecosistemas factibles de ser analizadas mediante el empleo de parámetros energéticos, en base a la estrecha vinculación entre el consumo de energía, la productividad de los agroecosistemas y la intensificación de la agricultura. Desde 1970 se verificó un incremento en las cantidades de energía empleadas por los agroecosistemas mientras que la eficiencia energética permaneció en valores altos, producto de los aumentos de rendimiento registrados. El cultivo de trigo resultó el de menor eficiencia energética. En el actual modelo tecnológico se obtiene el mayor rendimiento energético de la mano de obra.

La energía eólica en España y su contribución al desarrollo rural

Directory of Open Access Journals (Sweden)

Rosario Galdos Urrutia

2009-01-01

Full Text Available En los últimos años se ha producido en España un fuerte incremento de la demanda de energía primaria que no se ha acompañado de un crecimiento similar en la producción nacional, aumentando de este modo la dependencia energética con el exterior. Y ello a pesar del desarrollo de las energías renovables y especialmente de la eólica. El crecimiento del sector eólico no sólo ha convertido a España en el tercer país del mundo por potencia instalada sino que ha generado un activo tejido industrial con empresas de referencia internacional. Muchas de estas industrias eólicas así como la mayoría de los parques de aerogeneradores se localizan en pequeños municipios, contribuyendo al desarrollo de los mismos gracias a los beneficios económicos que generan.

Caracterización energética de un sistema mixto de recuperación de energía en instalaciones de climatización. // Energetic characterization of an energy mixed recovery system on climatization facilities.

Directory of Open Access Journals (Sweden)

M. A. Alvarez-Guerra Plasencia

2001-07-01

Full Text Available Se realiza la caracterización energética de un sistema mixto de recuperación de energía del aire de extracción de localesclimatizados compuesto por dos recuperadores dispuestos en serie en el conducto de impulsión, recuperadores del tipotubos de calor (Heat Pipe y evaporativo indirecto de placas. Para ello se desarrolla un programa experimental encaminadoa evaluar la influencia de factores como la temperatura, humedad relativa y caudal del aire exterior, flujo de agua y % derecirculación del aire de retorno sobre las características fundamentales definidas para el sistema mixto: Flujo de calorrecuperado, eficacia térmica y coeficiente de prestaciones.Palabras claves: Recuperación de energía, tubos de calor, humedad relativa, flujo de aire primario,recirculación de aire de retorno._______________________________________________________________________________AbstractThe energetic characterisation of a mixed system of energy recovery from exhaust room air, compound by recuperators oftwo types: heat pipe and indirect evaporative with plates type, have been developed. For this purpose an experimentalprogram has been created to evaluate the influence of different parameters such as: Temperature, Relative Humidity,Primary Air Flow, Water Flow and the Secondary Air Recirculation Ratio on it’s thermal performance.Key words: Energy recovery, heat pipes, relative humidity, primary air flow, secondary air recirculation.

La evolución energética del sector español de baldosas cerámicas

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Monfort, E.

2014-06-01

Full Text Available This paper analyses how energy consumption and energy efficiency evolved in the Spanish ceramic tile industry in the 20th century and explores the emerging possibilities in the 21st century. In the last century, the tile industry undertook three radical transitions by switching from traditional biomass fuels to liquid hydrocarbon fuels (fuel oil and gas oil, and subsequently to gas fuels, mainly involving natural gas. Although it is difficult to obtain the information that enable the real energy efficiency in manufacturing plants to be reliably evaluated, the available data indicate that a high degree of efficiency has been achieved with current manufacturing technologies. Consequently, significant developments in this sense are not expected, even though efforts are still being made to reduce energy consumption in the production process. However, environmental regulations and impacts, and the emerging new energy sources based on agricultural biomass could open up new avenues for energy supply in the Spanish ceramic tile cluster.El presente texto analiza cómo ha ido evolucionando el consumo y la eficiencia energética de la industria española de baldosas cerámicas durante el siglo XX, y explora las posibilidades que se le plantean en el siglo XXI. Durante el pasado siglo este sector industrial acometió tres transiciones radicales al pasar de los combustibles tradicionales de biomasa a los hidrocarburos líquidos (fuelóleo y gasóleo, y posteriormente a los gaseosos, principalmente gas natural. Aunque la información que permite evaluar de manera fiable la eficiencia energética real en las plantas de fabricación no es fácil de obtener, los datos disponibles indican que se ha llegado a una elevada eficiencia con las tecnologías productivas actualmente utilizadas. Por tanto no se prevén cambios importantes en este aspecto, aunque siguen realizándose esfuerzos encaminados a reducir el consumo de energía en el proceso productivo. Sin

Ion Composition and Energization in the Earth's Inner Magnetosphere and the Effects on Ring Current Buildup

Science.gov (United States)

Keika, K.; Kistler, L. M.; Brandt, P. C.

2014-12-01

In-situ observations and modeling work have confirmed that singly-charged oxygen ions, O+, which are of Earth's ionospheric origin, are heated/accelerated up to >100 keV in the magnetosphere. The energetic O+ population makes a significant contribution to the plasma pressure in the Earth's inner magnetosphere during magnetic storms, although under quiet conditions H+ dominates the plasma pressure. The pressure enhancements, which we term energization, are caused by adiabatic heating through earthward transport of source population in the plasma sheet, local acceleration in the inner magnetosphere and near-Earth plasma sheet, and enhanced ion supply from the topside ionosphere. The key issues regarding stronger O+ energization than H+ are non-adiabatic local acceleration, responsible for increase in O+ temperature, and more significant O+ supply than H+, responsible for increase in O+ density. Although several acceleration mechanisms and O+ supply processes have been proposed, it remains an open question what mechanism(s)/process(es) play the dominant role in stronger O+ energization. In this paper we summarize important spacecraft observations including those from Van Allen Probes, introduces the proposed mechanisms/processes that generate O+-rich energetic plasma population, and outlines possible scenarios of O+ pressure abundance in the Earth's inner magnetosphere.

Monitoreo energético experimental de vivienda unifamiliar compacta en un clima templado frio de Argentina

Directory of Open Access Journals (Sweden)

Celina Filippín

Full Text Available En el presente trabajo se estudia el comportamiento térmico-energético de viviendas compactas entre medianeras implantadas en barrios residenciales de baja densidad en la ciudad de Santa Rosa, La Pampa, Argentina (latitud: 36º27'S y longitud: 64º27'W. Los objetivos son evaluar la temperatura interior y las condiciones de confort en invierno a través del monitoreo experimental y analizar el consumo histórico de gas natural en calefacción. Los resultados muestran que las viviendas compactas entre medianeras tienen un 50% menos de consumo de gas natural que la vivienda social unifamiliar en la misma región en estudio. El panorama energético de Argentina, la posibilidad de revisar Normativas y Códigos de Edificación, la tendencia del crecimiento de la construcción de viviendas en la región en estudio, el proceso de etiquetado de la edificación, entre otros aspectos, ameritan un análisis de la información de las características del stock de las edificios y de su performance energética. La creación de un protocolo de monitoreo armonizado de datos es imperativa.

ENERGIA EÓLICA: uma fonte energética limpa e renovável em nosso meio

Directory of Open Access Journals (Sweden)

GABRIEL MOREIRA

2011-07-01

Full Text Available Segundo o IBGE, no ano de 2010, a população brasileira teve um crescimento de 1,12%. Tendo em vista que tal crescimento necessita de uma grande demanda energética, precisa-se de fontes alternativas. Um bom meio supressor é a energia eólica. Meio de energia renovável e limpa. Segundo o documentário, Energia Eólica: a caçada pelos ventos, exibido pela TV Zabelê: “É uma dádiva da natureza o fato da nossa região ter esse grande potencial eólico [...].” No entanto, sua instalação necessita-se de grandes investimentos. Tendo em vista este grande crescimento populacional o projeto de pesquisa Energia Eólica: Uma fonte energética limpa e renovável em nosso meio, tem como objetivo a produção de um pequeno campo de energia eólica, em uma biblioteca na escola Oswaldo Cruz, na cidade de Sinop, Mato Grosso. Desta forma temos a possibilidade de reduzir 70% do consumo energético convencional, proporcionando uma economia financeira considerável. A implantação deste projeto está prevista para o segundo semestre de 2014.

Comparación de Demandas Energéticas en Viviendas Unifamiliares en Climas Extremos

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Carolina Reyes Morales

2017-12-01

Full Text Available En Chile se están definiendo metas en el ámbito del uso de la energía, que acercan cada vez más la construcción al tipo sustentable. Esto queda evidenciado con el Código de Construcción Sustentable, donde además de establecerse nuevas exigencias con lo que respecta a las transmitancias térmicas de los parámetros opacos y acristalados, se presentan límites en las demandas máximas para climatización. Pese a que para la Región de Magallanes la construcción sustentable es un gran desafío, dadas las extremas condiciones climáticas a las que está sometida y la gran lejanía existente con las principales empresas del rubro, lo cual eleva considerablemente los costos, en los últimos años se han buscado alternativas que permitan mejorar los estándares constructivos y cumplir con las nuevas metas país. Este artículo presenta el trabajo desarrollado para establecer la línea base energética en el sector residencial privado de la Región de Magallanes en Chile, con el fin de conocer el estándar actual de construcción, a través del estudio de las especificaciones técnicas de los proyectos y mediciones de temperatura, humedad e infiltraciones. La metodología utilizada fue trabajar mediante simulación, con el software Design Builder v.4, todos los parámetros mencionados, para veinte modelos de viviendas del sector privado de la región, lo que ha permitido establecer diferencias entre los requerimientos energéticos para mantener el confort 24/7 y las demandas existentes en ellas establecidas por los sistemas de calefacción reales y los horarios de uso. Los primeros resultados muestran que en la Región de Magallanes las demandas requeridas para un confort 24/7 son en promedio 550 [kWh/m2] y si bien para las demandas existentes los resultados son similares, no se alcanzan temperaturas óptimas dada la alta cantidad de pérdidas energéticas producto de infiltraciones y un sistema de calefacción inapropiado. Esta situación que

Modulation of photosystem II chlorophyll fluorescence by electrogenic events generated by photosystem I

NARCIS (Netherlands)

Bulychev, A.A.; Vredenberg, W.J.

2001-01-01

In an attempt to uncover electric field interactions between PS I and PS II during their functioning, fluorescence induction curves were measured on hydroxylamine-treated thylakoids of Chenopodium album under conditions ensuring low and high levels of photogenerated membrane potentials. In parallel

Contrasting effect of dark-chilling on chloroplast structure and arrangement of chlorophyll-protein complexes in pea and tomato : Plants with a different susceptibility to non-freezing temperature

NARCIS (Netherlands)

Garstka, Maciej; Venema, Jan Henk; Rumak, Izabela; Gieczewska, Katarzyna; Rosiak, Malgorzata; Koziol-Lipinska, Joanna; Kierdaszuk, Borys; Vredenberg, Wim J.; Mostowska, Agnieszka

2007-01-01

The effect of dark-chilling and subsequent photoactivation on chloroplast structure and arrangements of chlorophyll-protein complexes in thylakoid membranes was studied in chilling-tolerant (CT) pea and in chilling-sensitive (CS) tomato. Dark-chilling did not influence chlorophyll content and Chl

Contrasting effect of dark-chilling on chloroplast structure and arrangement of chlorophyll-protein complexes in pea and tomato: plants with a different susceptibility to non-freezing temperature

NARCIS (Netherlands)

Garstka, M.; Venema, J.H.; Rumak, I.; Gieczewska, K.; Rosiak, M.; Koziol-Lipinska, J.; Vredenberg, W.J.; Mostowska, A.

2007-01-01

The effect of dark-chilling and subsequent photoactivation on chloroplast structure and arrangements of chlorophyll-protein complexes in thylakoid membranes was studied in chilling-tolerant (CT) pea and in chilling-sensitive (CS) tomato. Dark-chilling did not influence chlorophyll content and Chl

An organelle-free assay for pea chloroplast Mg-chelatase: Resolution of the activity into soluble and membrane bound fractions

Energy Technology Data Exchange (ETDEWEB)

Walker, C.J.; Weinstein, J.D. (Clemson Univ, SC (United States))

1991-05-01

Mg-chelatase, which catalyzes the insertion of magnesium into protoporphyrin, lies at the branchpoint of heme and chlorophyll biosynthesis in chloroplasts. Since magnesium chelation is the first step unique to chlorophyll synthesis, one would expect this step to be highly regulated. However, to date little is known about the enzymology or regulation of Mg-chelatase due mostly to an inability to assay it's activity outside of the intact plastid. Here the authors report the first truly in vitro i.e. organelle-free, assay for Mg-chelatase. Mg-chelatase activity in intact pea chloroplasts which is 3 to 4 fold higher than in cucumber chloroplasts, survived chloroplast lysis and could be fractionated, by centrifugation, into supernatant and pellet components. Both of these fractions were required to reconstitute Mg-chelatase activity and both were inactivated by boiling; indicating that the enzyme is composed of soluble and membrane bound protein(s). The specific activity of the reconstituted system was typically 1 nmol Mg-Deuteroporphyrin/h/mg protein and activity was linear for at least 60 min under our assay conditions. ATP and magnesium were required for Mg-chelatase activity. The soluble component could be fractionated with ammonium sulfate. The product of the reaction was confirmed fluorometrically as the magnesium chelate of the porphyrin substrate. Crude separation of chloroplast membranes into thylakoids and envelopes, suggested that the membrane-bound component of Mg-chelatase is probably located in the envelope.

The Use of Green Leaf Membranes to Promote Appetite Control, Suppress Hedonic Hunger and Loose Body Weight.

Science.gov (United States)

Erlanson-Albertsson, Charlotte; Albertsson, Per-Åke

2015-09-01

On-going research aims at answering the question, which satiety signal is the most potent or which combination of satiety signals is the most potent to stop eating. There is also an aim at finding certain food items or food additives that could be used to specifically reduce food intake therapeutically. Therapeutic attempts to normalize body weight and glycaemia with single agents alone have generally been disappointing. The success of bariatric surgery illustrates the rationale of using several hormones to treat obesity and type-2-diabetes. We have found that certain components from green leaves, the thylakoids, when given orally have a similar rationale in inducing the release of several gut hormones at the same time. In this way satiety is promoted and hunger suppressed, leading to loss of body weight and body fat. The mechanism is a reduced rate of intestinal lipid hydrolysis, allowing the lipolytic products to reach the distal intestine and release satiety hormones. The thylakoids also regulate glucose uptake in the intestine and influences microbiota composition in the intestine in a prebiotic direction. Using thylakoids is a novel strategy for treatment and prevention of obesity.

Photosystem II Water Oxidation: Mechanism, Efficiency and Flux in Diverse Oxygenic Phototrophs

Energy Technology Data Exchange (ETDEWEB)

Dismukes, Gerard Charles [Rutgers Univ., Piscataway, NJ (United States); Ananyev, Gennady [Rutgers Univ., Piscataway, NJ (United States); Gates, Colin [Rutgers Univ., Piscataway, NJ (United States)

2018-01-09

In one year, we pursued four aims: 1) extend the VZAD model to allow analysis of PSII chlorophyll fluorescence emission as modulated by interaction with the WOC (partial success); 2) compare the solar energy conversion efficiencies of PSII-WOCs from intact cells, isolated thylakoid membranes and PSII core complexes and crystals from cyanobacterium Thermosynechococcus elongatus (collaboration with Lawrence Berkeley National Laboratory; some success after changing collaborator); 3) determine whether PSIIs can store light energy by pumping protons across the thylakoid membrane (PSII-cyclic electron flow) and how it is regulated within the green alga Chlorella ohadii (collaboration with the Hebrew University of Jerusalem; some success); and 4) genetically replace the native PSII-D1 protein subunit from a higher plant with two cyanobacterial D1 isoforms to test whether their functional advantages in growth and photoprotection can be transferred (collaboration with Rutgers University; success).

Mechanism of Occurring Over-Voltage Phenomena in Distributed Power System on Energization of Transformers

Science.gov (United States)

Nakachi, Yoshiki; Ueda, Fukashi; Kajikawa, Takuya; Amau, Tooru; Kameyama, Hirokazu; Ito, Hisanori

This paper verifies the mechanism of occurring over voltage phenomena in the distributed power system on energizing the transformer. This over-voltage, which is observed at the actual distributed power system, with heavy inrush current is found to occur at about 0.1-0.2sec after the energizing and continue for a duration of more than 0.1[sec]. There is a concern that this over-voltage may operate the protection relay and deteriorate the insulation of apparatus. It is basically caused by the resonance between the shunt capacitors and saturated/unsaturated magnetizing inductance of transformer, system inductance. By using analytical formulation of a simple equivalent circuit, its mechanism has been verified through simulations carried out by using EMTP. Moreover, the sympathetic interaction between transformers is prolonged the duration of the over-voltage by the field test data is discussed in this paper.

Eficiencia energética en microempresas de Medellín: un estudio de valoración de barreras

OpenAIRE

Juan Gabriel Vanegas López; Sergio Botero Botero

2012-01-01

La difusión y penetración de medidas de uso eficiente de energía tienen impactos positivos tanto sobre la competitividad como sobre las condiciones de seguridad de las firmas. Empero, tales impactos son difíciles de alcanzar en la práctica debido a la presencia de barreras que limitan la toma de decisiones por parte de los agentes económicos. Este trabajo identifica, evalúa y valora una serie de barreras al uso eficiente de energía en microempresas de Medellín (Colombia). Mediante el método P...

Propuestas de mejora al mercado de energía mayorista para asegurar la confiabilidad del Sistema Interconectado Nacional

OpenAIRE

Castillo Marín, Jaime Alonso

2016-01-01

Las fallas de mercado justifican la regulación en los mismos y dadas las características del sector eléctrico se han realizado diseños de mercados en búsqueda de una asignación eficiente de los recursos -- Este diseño para el Mercado de Energía Mayorista en Colombia se ha mantenido en esencia igual desde sus inicios, a excepción de la creación del mercado de confiabilidad desarrollado posteriormente -- Ante periodos de escasez en la oferta, en el Mercado de Energía Mayorista se ha visto la ne...

A recruiting protein of geranylgeranyl diphosphate synthase controls metabolic flux toward chlorophyll biosynthesis in rice.

Science.gov (United States)

Zhou, Fei; Wang, Cheng-Yuan; Gutensohn, Michael; Jiang, Ling; Zhang, Peng; Zhang, Dabing; Dudareva, Natalia; Lu, Shan

2017-06-27

In plants, geranylgeranyl diphosphate (GGPP) is produced by plastidic GGPP synthase (GGPPS) and serves as a precursor for vital metabolic branches, including chlorophyll, carotenoid, and gibberellin biosynthesis. However, molecular mechanisms regulating GGPP allocation among these biosynthetic pathways localized in the same subcellular compartment are largely unknown. We found that rice contains only one functionally active GGPPS, OsGGPPS1, in chloroplasts. A functionally active homodimeric enzyme composed of two OsGGPPS1 subunits is located in the stroma. In thylakoid membranes, however, the GGPPS activity resides in a heterodimeric enzyme composed of one OsGGPPS1 subunit and GGPPS recruiting protein (OsGRP). OsGRP is structurally most similar to members of the geranyl diphosphate synthase small subunit type II subfamily. In contrast to members of this subfamily, OsGRP enhances OsGGPPS1 catalytic efficiency and specificity of GGPP production on interaction with OsGGPPS1. Structural biology and protein interaction analyses demonstrate that affinity between OsGRP and OsGGPPS1 is stronger than between two OsGGPPS1 molecules in homodimers. OsGRP determines OsGGPPS1 suborganellar localization and directs it to a large protein complex in thylakoid membranes, consisting of geranylgeranyl reductase (OsGGR), light-harvesting-like protein 3 (OsLIL3), protochlorophyllide oxidoreductase (OsPORB), and chlorophyll synthase (OsCHLG). Taken together, genetic and biochemical analyses suggest OsGRP functions in recruiting OsGGPPS1 from the stroma toward thylakoid membranes, thus providing a mechanism to control GGPP flux toward chlorophyll biosynthesis.

Melhoria da eficiência energética em sistemas motrizes industriais

Directory of Open Access Journals (Sweden)

Antonio Vanderley Herrero Sola

2015-09-01

Full Text Available A comunidade científica internacional tem considerado o uso eficiente de energia em sistemas de produção extremamente importante para o desenvolvimento sustentável. Este artigo estuda a melhoria da eficiência energética em sistemas motrizes industriais por meio de mudança tecnológica. Inicialmente é feita uma revisão de literatura para apresentar as principais ações e barreiras para a melhoria da eficiência energética em sistemas industriais de energia e também destacar o uso de uma abordagem multicritério em caso de mudança tecnológica. O artigo apresenta um estudo de caso em uma indústria com o objetivo de ordenar motores elétricos para serem substituídos utilizando o método multicritério PROMETHEE II. O estudo revela que a escolha dos critérios pode alterar a ordem de prioridade de escolha das tecnologias a serem substituídas, com impacto no desempenho das novas tecnologias. O artigo enfatiza a importância da integração de todas as áreas da empresa para que sejam atendidos os interesses da organização.

Consecuencias nutritivas de la sustitución energética de la proteina dietaria por grasa y/o hidratos de carbono en la trucha

OpenAIRE

Cardenete Hernández, Gabriel

2011-01-01

Puesto que la trucha utiliza buena parte de la proteína dietaria con fines energéticos se ha alimentado a truchas arcoiris con 5 dietas experimentales cuya relación proteína/energía disminuye progresivamente gracias a la adición degrasa y almidón y a la real sustitución de parte de la proteína por estas fuentes energéticas en 2 grupos de experimentos: a nivel piloto y semiindustrial. La acumulación proteica en la carcasse es prácticamente idéntica para todas las dietas siendo el factor determ...

On the potential application of polar and temperate marine microalgae for EPA and DHA production

NARCIS (Netherlands)

Boelen, P.; van Dijk, R.; Sinninghe Damsté, J.S.; Rijpstra, W.I.C.; Buma, A.G.J.

2013-01-01

Long chain polyunsaturated fatty acids (LC-PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are considered essential omega-3 fatty acids in human nutrition. In marine microalgae EPA and/or DHA are allegedly involved in the regulation of membrane fluidity and thylakoid

Estudi energètic d'un cotxe híbrid elèctric

OpenAIRE

Cedó Olivé, Gerard

2016-01-01

L’objectiu del present estudi és analitzar i comprendre el comportament energètic d’un vehicle híbrid elèctric, mitjançant la creació i la simulació d’un model dinàmic utilitzant l’entorn de programació visual SIMULINK®, del programa informàtic MATLAB®.

Transverse ion energization and low-frequency plasma waves in the mid-altitude auroral zone - A case study

Science.gov (United States)

Peterson, W. K.; Shelley, E. G.; Boardsen, S. A.; Gurnett, D. A.; Ledley, B. G.; Sugiura, M.; Moore, T. E.

1988-01-01

Evidence of transverse ion energization at altitudes of several earth radii in the auroral zone was reexamined using several hundred hours of high-sensitivity and high-resolution plasma data obtained by the Dynamics Explorer 1 satellite. The data on particle environment encountered at midaltitudes in the auroral zone disclosed rapid variations in the values of total density, thermal structure, and composition of the plasma in the interval measured; the modes of low-frequency plasma waves also varied rapidly. It was not possible to unambiguously identify in these data particle and wave signature of local transverse ion energization; however, many intervals were found where local transverse ion heating was consistent with the observations.

Impacto de la envolvente en la demanda de energía en calefacción residencial de la región metropolitana de La Plata, tomando como caso testigo el reciclado energético de una vivienda

Directory of Open Access Journals (Sweden)

María de la Paz Diulio

Full Text Available Resumen El área metropolitana de La Plata representa el 1,6% de las viviendas de la Argentina. A partir del análisis del reciclado de una vivienda se construyen indicadores básicos con el fin de proponer una metodología que facilite la extrapolación, a nivel regional, del impacto que causaría un programa de eficiencia energética en viviendas. Se exponen desde el nivel micro a macro los resultados obtenidos en un contexto de carestía energética y recurrentes crisis en la oferta de combustibles y electricidad en la Argentina. La mejora en la resistencia térmica de muros y techos en todo el parque residencial de La Plata conllevaría a una reducción del 12% de la energía consumida en calefacción, y un ahorro de 30.000 TEP/año. Se concluye que la incidencia que implica la colocación de aislación adicional respecto del costo de la construcción justifica su uso, resolviendo parcialmente la falta de combustibles en el país, reduciendo gastos fijos en la vivienda, otorgando confort térmico a los usuarios y generando reactivación del sector de la construcción.

Requerimientos sectoriales de energía eléctrica en México. Una aplicación del concepto de entropía de Theil al análisis insumo-producto

OpenAIRE

Gastélum Valdez, Martha Janet

2009-01-01

La investigación estima los requerimientos sectoriales de energía eléctrica en México. Se utilizan tres metodologías: 1) la que calcula los requerimientos de energía primaria a través de los balances energéticos; 2) las necesidades de energía eléctrica obtenido del modelo insumo-producto y 3) el uso del índice de Theil y una medida de concentración con vínculos hacia delante y hacia atrás que mide el grado de inter-conectividad. Los altos valores de las entropías confirman que la importancia ...

Evaluación económica y social del uso del bagazo de caña en la generación de energía eléctrica en Nicaragua

Directory of Open Access Journals (Sweden)

Napoleón Vicente Blanco-Orozco

2014-09-01

La evaluación social del empleo del bagazo de caña en la generación de energía utilizando la metodología de multicriterio, apoyada en el método de consulta a expertos, mostró que los ingenios que usan este energético tienen impactos positivos. Asimismo, esta evaluación social demuestra que las plantas que utilizan combustibles fósiles en la generación de energía, y estudiadas para esta investigación, encarecen el precio de la energía eléctrica y en el proceso producen gases contaminantes como CO2.

Monitorização do desempenho energético de um veículo híbrido Lexus

OpenAIRE

Luzia, Marco José da Silva Brandão

2009-01-01

As preocupações ambientais conjuntamente com a dependência energética da nossa sociedade levam a que o sector dos transportes seja aquele em que os países estão a focar a sua atenção de maneira a reduzir o impacto energético e ambiental do mesmo, de maneira a tornar a mobilidade mais sustentável. Uma das soluções passa por uma política integrada em matéria de energia e alterações climáticas, surgindo, além de outras medidas o Protocolo de Quioto e a aposta dos construtores e Governos em co...

Desarrollo de una herramienta para validar la influencia del comportamiento del usuario sobre la eficiencia energética en edificios públicos de oficinas.

Directory of Open Access Journals (Sweden)

Alción de las Pléyades Alonso Frank

2016-12-01

Full Text Available La problemática ambiental global conduce a que numerosos países incorporen estrategias de Eficiencia Energética (EE a fin de disminuir el consumo de energía, aspecto que valoran mediante etiquetados o pasaportes de EE. Como hipótesis se considera que los usuarios de edificios son responsables del consumo de energía no previsto en la etapa de funcionamiento, por lo que el objetivo del presente trabajo es desarrollar y validar una herramienta de valoración del comportamiento de usuarios de espacios de trabajo en edificios públicos de oficinas. Para ello, se lleva a cabo un trabajo de campo en tres edificios ubicados en la ciudad de San Juan, Argentina. Se realizan encuestas a fin de evaluar los hábitos que el usuario emplea como estrategias para satisfacer su condición de confort térmico, en correlación con los consumos de energía registrados. Se elabora un indicador del Nivel de Eficiencia del Usuario (NEU y se transfiere a una etiqueta, a efectos de obtener una rápida aprehensión por parte del mismo. Los resultados reflejan variaciones en la frecuencia de uso de artefactos de climatización, apertura de puertas y ventanas, control de parasoles y cortinas y modificación de la ropa por los usuarios, llegando a observarse variaciones del consumo energético del edificio. Los valores obtenidos del NEU, permiten demostrar la eficiencia del comportamiento de usuarios en relación al cuidado de la energía.

Energía renovable e hidrógeno generados in situ para riego y movilidad en viñedos

Directory of Open Access Journals (Sweden)

Carroquino Javier

2017-01-01

Full Text Available La energía utilizada en agricultura es fuente de emisiones de gases de efecto invernadero. Para reducir las producidas por el uso de gasóleo y electricidad, el proyecto europeo LIFE REWIND aborda el suministro desde fuentes renovables. Para ello, se ha caracterizado la demanda energética y recursos renovables en viñedo y bodega. Se ha buscado el diseño óptimo económico y medioambiental de la generación. Se ha instalado un prototipo en una explotación vitivinícola, con generación fotovoltaica, incluyendo un conjunto flotante sobre una balsa. Esto evita el uso de terreno, reduce la pérdida de agua de la balsa y mejora el rendimiento de los paneles fotovoltaicos. La electricidad producida alimenta la depuración de agua y el bombeo de riego por goteo del viñedo. Con la energía sobrante, un electrolizador produce hidrógeno mediante electrólisis del agua, que es utilizado por un vehículo todoterreno con pila de combustible. Los resultados muestran la viabilidad técnica y económica de los sistemas autónomos de energía renovable para alimentar el riego estacional en los viñedos. Así se evitan las extensiones indiscriminadas de la red y los grupos electrógenos diésel. Adicionalmente se muestra la posibilidad de reemplazar el gasóleo por electricidad o hidrógeno producido en la propia explotación.

Voltage dip caused by the sequential energization of wind turbine transformers

DEFF Research Database (Denmark)

Arana Aristi, Iván; Holbøll, Joachim; Sørensen, T.

2009-01-01

motors, this recommendation automatically applies to the wind turbine transformers in a wind farm, regardless of the fact that wind turbine transformers are rarely energized and the investment of timed relays might be significant. At the design stage of the collection grid of large offshore wind farms...... farms in Denmark and the UK. However, there is still work to be done to optimize the investment and protection system of the internal grid of the wind power plants....

Almacenamiento de energía mediante aire comprimido: Plantas CAES.

OpenAIRE

Muñoz Diez de la Cortina, Alejandro

2015-01-01

El presente proyecto estudia el estado del arte en cuanto a tecnología CAES se refiere, en un intento de compilación de la información disponible en distintos medios de divulgación científica e ingenieril, y haciendo una presentación de las distintas mejoras y desarrollos posibles de la tecnología así como de un acercamiento a las dos plantas ya existentes que utilizan este medio de almacenamiento de energía. El núcleo del proyecto se encuentra en el estudio de los sistemas ...

Coste energético del dribling en hockey sobre patines

OpenAIRE

Blanco, Dr. Alfonso; Balagué, Dra. Natàlia

1997-01-01

El objetivo del presente estudio ha sido analizar y comparar el coste energético del dribling en hockey sobre patines con respecto a la acción de patinar. Doce jugadores amateurs bien entrenados han realizado, durante cinco minutos a 11, 13 y 15 km/h, patinaje solamente y patinaje mientras driblaban la bola con el stick. En ambos casos se evaluaron directamente y compararon consumo de oxígeno, ventilación, frecuencia cardíaca y nivel de percepción subjetiva del esfuerzo. Las variables fisioló...

Sensoriamento remoto como subsídio à modelagem do balanço energético superficial

Directory of Open Access Journals (Sweden)

Vassiliki Terezinha Galvão Boulomytis

2010-09-01

Full Text Available O balanço energético superficial interfere no funcionamento do sistema terrestre através da relação existente entre a água e a energia solar e do modo como ocorre o seu processo de partição. Para a sua estimativa, modelagens vêm sendo realizadas utilizando-se de um ou mais sensores com diferentes resoluções, a fim de se obter dados com resoluções temporal e espacial adequadas a uma escala local. Neste estudo serão apresentados modelos para estimar a evapotranspiração e outros parâmetros biofísicos através do balanço energético superficial com a utilização dos sensores MODIS e AMSR-E.

A Femtosecond Visible/Visible and Visible/Mid-Infrared Transient Absorption Study of the Light Harvesting Complex II

NARCIS (Netherlands)

Stahl, A.D.; Di Donato, M.; van Stokkum, I.H.M.; van Grondelle, R.; Groot, M.L.

2009-01-01

Light harvesting complex II (LHCII) is the most abundant protein in the thylakoid membrane of higher plants and green algae. LHCII acts to collect solar radiation, transferring this energy mainly toward photosystem II, with a smaller amount going to photosystem I; it is then converted into a

Architecture of the light-harvesting apparatus of the eustigmatophyte alga Nannochloropsis oceanica

Czech Academy of Sciences Publication Activity Database

Litvín, Radek; Bína, David; Herbstová, Miroslava; Gardian, Zdenko

2016-01-01

Roč. 130, 1-3 (2016), s. 137-150 ISSN 0166-8595 R&D Projects: GA ČR(CZ) GP14-01377P Institutional support: RVO:60077344 Keywords : Light harvesting * Thylakoid membrane * Vaucheriaxanthin * Violaxanthin–chlorophyll protein Subject RIV: BO - Biophysics Impact factor: 3.864, year: 2016

Análisis beneficio-costo y cuantificación de la energía invertida en sistemas de caficultura campesina en Puriscal, Costa Rica

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Jairo Mora-Delgado

2006-01-01

Full Text Available Tres modelos de sistemas de producción de caficultura campesina en el Cantón de Puriscal, Costa Rica, fueron estudiados para determinar la relación beneficio-costo y estimar la energía invertida por producto obtenido. Los 3 modelos hipotéticos fueron el resultado del agrupamiento de 39 fincas, realizado mediante un análisis de conglomerados (cluster analysis, del cual resultaron 3 grupos. El primero fue denominado fincas de tecnología orgánica (TO, caracterizadas por utilizar recursos endógenos en su sistema de producción, principalmente tecnologías orgánicas. El segundo se caracterizó por ser fincas convencionales, donde se distinguieron 2 subgrupos: fincas de tecnología mixta (TM y fincas de tecnología convencional (TC. Las segundas usan tecnologías y recursos convencionales; las primeras funcionan bajo un esquema de caficultura convencional, pero han incorporado algunas prácticas y recursos de la agricultura orgánica. Se realizó un análisis beneficio-costo en 3 modelos hipotéticos, que representan a cada uno de los grupos de fincas definidos. Mediante el método de procesos, para evaluar la productividad de la energía, se estimó la cantidad de energía invertida en insumos y mano de obra en los 3 modelos; para ello se empleó factores de conversión reportados en diferentes estudios, y dichos valores fueron convertidos a valores de energía. Los beneficios financieros más altos, en el corto plazo, se obtuvieron en el modelo TC, comparado con los sistemas TO y TM. Sin embargo, desde el punto de vista de la productividad de la energía, el modelo de caficultura orgánica es el que presenta una mayor eficiencia energética, en la medida en que para producir 1 kg de café en cereza se invirtió 0,51 MJ kg-1, que es 50% de la energía requerida para producir el mismo kg en los modelos TC (1,06 MJ kg-1 y TM (0,97 MJ kg-1.

El etanol carburante en la costa norte del Perú. Impactos energético, ambiental y socioeconómico

OpenAIRE

Lizana Bobadilla, Víctor Manuel

2016-01-01

EL Perú es un país Iberoamericano que desde fines de la década de los 90 ha experimentado un crecimiento notable y sostenido debido a la reactivación económica y al desarrollo de algunos de sus sectores productivos principales como la minería, la industria, la construcción y el transporte. En este marco, el sector energético ha cumplido un papel importante para satisfacer el incremento de la demanda energética nacional. Perú se ha caracterizado por una elevada dependencia de los combusti...

Auditoría energética de las instalaciones de la empresa ecuatoriana de artefactos S.A. “ECASA”

OpenAIRE

Cárdenas Ayala, Byron Mauricio

2017-01-01

Este proyecto realiza una auditoría energética en la empresa Ecuatoriana de Artefactos S.A. ECASA, que fabrica electrodomésticos de línea blanca. Se elabora una línea base del consumo energético actual por unidad producida, se identifican las oportunidades de mejora y se propone la ejecución de las mejoras con cero y bajo costo de implementación. Se entrega un plan de verificación de la implementación de las medidas propuestas. Se inicia el proceso con una evaluación sin mediciones para iden...

Evaluación energética de un sistema de generación de 400 kWe en modo diesel-gas licuado de petróleo

OpenAIRE

Forero-Núñez, Carlos-A.; Eduardo-Arango, Jorge; Sierra-Vargas, Fabio-Emiro

2014-01-01

El constante aumento en los precios de los combustibles impulsó el desarrollo de sistemas energéticos cada vez más eficientes y flexibles, los cuales permitan el uso de distintos tipos de combustibles, tales como el gas licuado de petróleo (GLP). El presente trabajo buscó analizar el comportamiento energético y ambiental que tiene una planta de generación de 400 kWe operada en modo diesel y dual diesel-GLP de pozo. La eficiencia energética total del sistema en el punto de máxima carga fue igu...

Innovación en el diseño instruccional de cursos masivos abiertos con gamificación y REA para formar en sustentabilidad energética.

OpenAIRE

Argueta Velázquez, Martha G.

2017-01-01

El presente estudio forma parte de una agenda pública nacional de desarrollo de la energía sostenible en México, específicamente del Proyecto Laboratorio Binacional para la Gestión Inteligente de la Sustentabilidad Energética y la Formación Tecnológica. El estudio, en última instancia, tiene como propósito principal contribuir a la fundamentación de un modelo de diseño instruccional (DI) de un curso masivo abierto en línea (MOOC), por sus siglas en inglés, sobre sostenibilidad energética. En ...

El nexo entre cambio climático y energía renovable en el Mercosur. Un análisis comparativo de las legislaciones de Argentina y Brasil

OpenAIRE

Casola, Laura; Freier, Alexander

2017-01-01

El sector energético es uno de los principales contribuyentes al cambio climático debido a la combustión de hidrocarburos, por lo que la energía renovable se presenta como una alternativa para promover el desarrollo sustentable. En ese sentido, aplicando una metodología comparativa, este artículo analiza las regulaciones sobre cambio climático y energía renovable en Argentina y Brasil, considerados los dos Estados política y económicamente más fuertes del Mercosur, los cuales están especialme...

Optimización térmica y energética de la doble fachada acristalada con ventilación mecánica en clima mediterráneo

OpenAIRE

Cuerva Contreras, Eva

2013-01-01

El diseño de edificios siguiendo criterios de sostenibilidad y eficiencia energética se ha convertido en un imperativo en los países desarrollados, sobre todo a raíz de la Directiva europea 2010/31/UE sobre Eficiencia Energética en los Edificios, cuyo objetivo para el año 2019 es el de conseguir zero-emission buildings, es decir, edificios cuyo impacto sobre el entorno sea casi nulo, al ser autosuficientes energéticamente y no emitir gases de efecto invernadero. En respuesta a esta corrien...

Comparación de la ingesta de energía y nutrientes en adolescentes mujeres con sobrepeso y obesidad

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Jaime Pajuelo R

2013-01-01

Full Text Available Introducción: El sobrepeso y la obesidad son consecuencia de una modificación de los patrones dietarios y de una actitud cada vez más sedentaria. Objetivos: Comparar la ingesta de energía y nutrientes de adolescentes mujeres con sobrepeso y obesidad. Diseño: Estudio transversal, observacional y analítico. Lugar: Centro Educativo de la zona urbana de Lima. Participantes: Adolescentes entre 10 a 18 años. Intervención: Se estudió 100 adolescentes con sobrepeso y 87 con obesidad. El diagnóstico se hizo mediante el índice de masa corporal (IMC, con la población de referencia de la Organización Mundial de la Salud (OMS y con los niveles de corte entre 85 y 95 percentil para sobrepeso y más de 95 para obesidad. La evaluación de la cantidad de energía y de nutrientes se realizó mediante un cuestionario de frecuencia semicuantitativo, utilizando la Tabla Peruana de Composición de Alimentos y la del Departamento de Agricultura de los EE UU. Para el porcentaje de adecuación de la energía y para la identificación cuantitativa de la ingesta de vitaminas y mineral se utilizó las recomendaciones de la FAO. El análisis estadístico se hizo con la prueba t-Student para comparación de medias. Principales medidas de resultados: Energía ingerida, adecuación de los nutrientes, cantidad de vitaminas y minerales ingeridos, de acuerdo a los grupos estudiados. Resultados: No hubo diferencia de la ingesta de energía entre los grupos estudiados, y estos valores fueron menores que los requerimientos. La adecuación porcentual mostró que el consumo de las grasas estuvo por debajo del requerimiento; lo mismo sucedió con las grasas saturadas, monoinsaturadas y poliinsaturadas; sin embargo, lo que más se consumió fue la grasa saturada. En cuanto a las vitaminas y minerales, fueron ingeridas en cantidades que cubrían los requerimientos, a excepción de los folatos. La ingesta de fibra fue muy pobre. Conclusiones: Se puede afirmar que el consumo

Monitoreo de funcionamiento y estrategias de eficiencia energética para el edificio público de Obras Sanitarias Sociedad del Estado, San Juan, Argentina

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Yesica Alamino Naranjo

2015-06-01

Full Text Available El incremento de la potencia instalada en los sectores de consumo, por encima de la capacidad de generación, en los últimos diez años, sitúa a Argentina como país dependiente energéticamente. Una de las medidas de mitigación de las consecuencias ambientales, sociales y económicas asociadas, consiste en reducir el consumo de energía en los edificios. La sociedad pasa más del 30% de su tiempo en espacios de trabajo, en ambientes climatizados. Es objetivo del trabajo es encontrar estrategias de mejora sobre la eficiencia energética del edificio sin disminuir la calidad de vida de los usuarios. Para ello, se lleva a cabo un estudio de campo en el edificio sede de Obras Sanitaria Sociedad del Estado (OSSE, ubicado en la ciudad de San Juan (Argentina, mediante una aproximación experimental, contemplando aspectos funcionales, tecnológicos y referentes al equipamiento del edificio. Los resultados muestran valores de demanda de energía elevados en sistemas de climatización y artefactos de consumo eléctrico en oficinas. La implementación de estrategias de intervención de mínima inversión permitiría reducir el consumo energético en un 42% y recuperar más del 70% de la inversión durante el primer año de funcionamiento.

Implementació de criteris d'optimització energètica en vivenda unifamiliar contemplant l'ús d'energia solar fotovoltaica

OpenAIRE

Guàrdia Fargues, Clara

2017-01-01

Aquest projecte ofereix un mètode per tal d’optimitzar energèticament un habitatge unifamiliar. Aquest estudi contempla millorar els consums de l’habitatge i instal·lar un sistema híbrid connectat a la xarxa format per panells fotovoltaics, bateries i un generador dièsel. Aquest sistema es dissenyarà tenint en compte criteris de rendibilitat econòmica i eficiència energètica. Per la realització d’aquest projecte s’ha considerat la metodologia de la ISO 50001, que té com a objectiu la millo...

Incentivos fiscales para fomentar actuaciones de mejora en la eficiencia energética de viviendas de construcción antigua

OpenAIRE

Villca Pozo, Milenka

2017-01-01

Atendiendo a los objetivos que persigue el Real Decreto 235/2013, de 5 de abril, en relación con la exigencia de la certificación de eficiencia energética de las edificaciones nuevas y antiguas, desde el panorama tributario, se analiza si existen incentivos fiscales que promuevan la eficiencia energética de los edificios de construcción antigua. Del análisis de la normativa de los tributos que inciden en la propiedad, como son el Impuesto sobre el Patrimonio e Impuesto sobre Bienes Inmuebles,...

Avances en la evaluación de la eficiencia energética del proceso de producción de biodiesel para distintas escalas

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DONATO L

2012-04-01

Full Text Available ResumenEl biodiesel es un biocombustible producido por la reacción entre aceite vegetal o grasa animal y alcohol.El balance energético es uno de los puntos críticos al momento de evaluar la sustentabilidad del mismo. El objetivo de este trabajo es analizar la relación entre la energía consumida y generada en dos sistemas de producción de biodiesel: uno para autoconsumo en un establecimiento agropecuario y otro para abastecer el corte interno de gasoil y las exportaciones. Con datos de la etapa agrícola e industrial y mediante la aplicación de indicadores energéticos, se obtuvieron los resultados para cada caso. En el sistema de producción para autoconsumo, la colza y el girasol se presentan como las mejores alternativas desde el punto de vista energético. En el caso de la producción para el corte interno y exportación, el mejor resultado se produce con soja de siembra directa y tecnología de punta. Se necesitan conocer el consumo de energía fósil para la fabricación de los principales insumos (fertilizantes, agroquímicos y alcohol para obtener un análisis con mayor certeza del balance energético en nuestro país.biocombustibles; balance energético.AbstractBiodiesel is a biofuel produced by the reaction between vegetable oil or animal fat and alcohol. The energy balance is a critical point when assessing the sustainability. The aim of this study is to analyze the relationship between energy consumed and generated in two biodiesel production systems: one for consumption on a farm and other to supply the diesel blended and export. Using data from the agricultural and industrial stage by application of energy indicators, results were obtained for each case. In the system of production for own consumption, rapeseed and sunflower are presented as the best alternative from an energy standpoint. In production for domestic and export cut, soybean tillage system with advanced technology provides the best results of energy balance. In

Stromal serine protein kinase activity in spinach chloroplasts

International Nuclear Information System (INIS)

Cortez, N.; Lucero, H.A.; Vallejos, R.H.

1987-01-01

At least twelve 32 P-labeled stromal proteins were detected by electrophoresis under denaturing conditions when intact chloroplasts were incubated with 32 Pi, in the light but only three were detected in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) or in the dark. Incubation of isolated stroma with [gamma- 32 P]ATP resulted in the preferential phosphorylation of one of them, a 70-kDa polypeptide, in serine residues. Thylakoid membranes in the dark promoted the phosphorylation of two additional stromal polypeptides of 55 and 40 kDa. Illumination during the phosphorylation of stroma in the presence of thylakoids stimulated severalfold the labeling of the 40-kDa polypeptide but not when DCMU was added. The protein kinase activity present in isolated stroma phosphorylated exogenous substrates like histone III, phosvitin, histone II, and casein with specific activities of 3, 1.8, 0.7, and 0.2 pmol X mg-1 X min-1. Histone III polypeptides were phosphorylated differently by stroma and by thylakoids in the dark. Moreover, histone III phosphorylated by thylakoids in the dark yielded a pattern of phosphopeptides after V8 protease treatment that was different from the pattern obtained when histone III was phosphorylated by stroma

O efeito das bebidas alcoólicas pode ser afetado pela combinação com bebidas energéticas? Um estudo com usuários

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Ferreira Sionaldo Eduardo

2004-01-01

Full Text Available OBJETIVO: Avaliar em uma amostra de critério, o padrão de uso de bebidas energéticas, isoladamente e em associação com bebidas alcoólicas. MÉTODOS: Cento e trinta e seis voluntários (idade 24 ± 6 anos que relataram ao menos um uso anterior de bebidas energéticas foram submetidos a uma entrevista padronizada sobre hábitos de consumo de bebidas energéticas e alcoólicas. RESULTADOS: A maioria da amostra relatou usar bebidas energéticas tanto isoladamente (79% como em combinação com bebidas alcoólicas (76%, neste caso preferencialmente com uísque (90%, vodka (37% ou cerveja (13%. Após a ingestão isolada de bebidas energéticas, 61% relataram não sentir nenhum efeito, 10% mencionaram aumento da alegria, 9% euforia, 9% insônia, 7% desinibição e 24% aumento do vigor físico. Dos que relataram uso combinado com álcool, 14% relataram não sentir alteração dos efeitos do álcool, mas 38% reportaram aumento de alegria, euforia (30%, insônia (11%, desinibição (27% e do vigor físico (24%. Observou-se grande variabilidade no número de usos de bebidas energéticas na vida (14 ± 16, mas certa regularidade na quantidade ingerida por ocasião (1,5 ± 0,7 latas. CONCLUSÕES: Os dados sugerem que os efeitos das bebidas energéticas são bastante variáveis, dependendo provavelmente da dose ingerida e da sensibilidade individual. Alguns relatos sugerem que há interação com o álcool, expressa pelo aumento dos efeitos excitatórios ou redução de seus efeitos depressores. São discutidos possíveis mecanismos farmacológicos subjacentes a esta combinação.

Sistemas Integrados de energías con fuentes renovables, requisitos y opciones. Integrated systems of energy with renewable sources, requirements and options

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Antonio Sarmiento Sera

2015-04-01

Full Text Available En el presente reporte se consideró una instalación conectada a la red eléctrica en la isla de Cuba. Se tenía el interés de introducir un determinado % de energía a partir de fuentes renovables, y se poseía un determinado potencial de energía eólica y fotovoltaica. Se analizaron los requisitos y opciones energéticas, se realizaron simulaciones de alternativas con el programa HOMER y se concluyó con la determinación de las condiciones o potenciales de las fuentes renovables para la recomendación de cada opción energética, y se presentaron los resultados de forma gráfica y fácil comprensión. Se ofreció un análisis de las posibilidades reales que en el ámbito de una localidad, pueden aprovecharse en función de diversificar de manera sostenible, el esquema energético comunitario  con la utilización de las fuentes renovables de energía, utilizando la variante que desde el punto económico y ambiental resulte de más conveniencia.  In this report was considered an electric net connected installation in the island of Cuba. It had the interest of introducing a certain % of energy starting from renewable sources, and a certain potential of wind and photovoltaic energy was possessed. The requirements and energy options were analyzed, and it were carried out simulations of alternative with the HOMER program and it was concluded with the determination of the conditions or potentials of the renewable sources for the recommendation of each energy option, and the results were presented in graphic way and easy understanding. It was offered an analysis of the real possibilities in the environment of a town. It can take advantage in function of diversifying from a sustainable way, with the community energy outline using the renewable sources of energy, and taking the variant of more convenience from the economic and environmental point of view.

Structure, function and regulation of plant photosystem I

NARCIS (Netherlands)

Jensen, Poul Erik; Bassi, Roberto; Boekema, Egbert J.; Dekker, Jan P.; Jansson, Stefan; Leister, Dario; Robinson, Colin; Scheller, Henrik Vibe

Photosystem I (PSI) is a multisubunit protein complex located in the thylakoid membranes of green plants and algae, where it initiates one of the first steps of solar energy conversion by light-driven electron transport. In this review, we discuss recent progress on several topics related to the

Structure, function and regulation of plant photosystem I

NARCIS (Netherlands)

Jensen, P.E.; Bassi, R.; Boekema, E.J.; Dekker, J.P.; Jansson, S.; Leister, D.; Robinson, C.; Scheller, H.V.

2007-01-01

Photosystem I (PSI) is a multisubunit protein complex located in the thylakoid membranes of green plants and algae, where it initiates one of the first steps of solar energy conversion by light-driven electron transport. In this review, we discuss recent progress on several topics related to the

Temperature, energy acquisition and energy use in the Chilean silverside Basilichthys australis Eigenmann (Atherinopsidae Temperatura, adquisición de energía y uso de energía en el pejerrey chileno Basilichthys australis Eigenmann (Atherinopsidae

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LEOPOLDO FUENTES

2005-06-01

Full Text Available We evaluated the influence of water temperature (Tw on the energy acquisition and use in the chilean silverside Basilichthys australis (Eigenmann 1927, an endemic species inhabiting freshwater ecosystems in Chile. We tested the effect of Tw (11.5, 14.0, 18.0, 22.0 and 26.0 °C on food intake, digestibility, food transit time and metabolic rate. As expected, this study demonstrated that many physiological variables under study were significantly affected by Tw, as well as the net energy balance of this species. Nevertheless, the net energy balance was not strictly related to the range of Tws evaluated. At Tws lower than 14 °C the energy budget was depressed, because food intake was lower than at Tws between 14 and 26 °C, where food intake was higher and independent of Tw. Consequently, at these temperatures the energy balance was positive and also independent of Tw. Physiologically, B. australis appears to be a tolerant species with respect to the wide range of water temperature in habitats at different depths. Thus, its distributions may extend through the entire profile of lakes and rivers, even in systems characterised by spatial and temporal thermal variabilityEn este trabajo evaluamos la influencia de la temperatura del agua (Ta en la adquisición de energía y su uso por parte del pejerrey chileno Basilichthys australis (Eigenmann 1927, una especie endémica que habita los ecosistemas dulceacuícolas de Chile. Investigamos el efecto de Ta (11,5, 14,0, 18,0, 22,0 y 26,0 °C en la ingesta de alimento, digestibilidad, tiempo de transito del alimento y tasa metabólica. De acuerdo a lo esperado, este estudio demostró que varias de las variables fisiológicas bajo estudio fueron significativamente afectadas por Ta, así como el balance energético de esta especie. Sin embargo, el balance neto de energía no estuvo estrictamente relacionado al rango de Tas evaluadas. En Tas inferiores a 14 °C el presupuesto de energía fue deprimido, debido a

Protein kinase that phosphorylates light-harvesting complex is autophosphorylated and is associated with photosystem II

International Nuclear Information System (INIS)

Coughlan, S.J.; Hind, G.

1987-01-01

Thylakoid membranes were phosphorylated with [γ- 32 P]ATP and extracted with octyl glucoside and cholate. Among the radiolabeled phosphoproteins in the extract was a previously characterized protein kinase of 64-kDa apparent mass. The ability of this enzyme to undergo autophosphorylation in situ was used to monitor its distribution in the membrane. Fractionation studies showed that the kinase is confined to granal regions of the thylakoid, where it appears to be associated with the light-harvesting chlorophyll-protein complex of photosystem II. The kinetics of kinase autophosphorylation were investigated both in situ and in extracted, purified enzyme. In the membrane, autophosphorylation saturated within 20-30 min and was reversed with a half-time of 7-8 min upon removal of ATP or oxidative inactivation of the kinase; the accompanying dephosphorylation of light-harvesting complex was slower and kinetically complex. Fluoride (10 mM) inhibited these dephosphorylations. Autophosphorylation of the isolated kinase was independent of enzyme concentration, indicative of an intramolecular mechanism. A maximum of one serine residue per mole of kinase was esterified. Autophosphorylation was more rapid in the presence of histone IIIs, an exogenous substrate. Dephosphorylation of the isolated enzyme was not observed

Producción más limpia en las Américas: Manejo del recurso energético. Casos de estudio: Chile, Costa Rica y Nicaragua

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Melanny Zúñiga-Araya

2014-12-01

Full Text Available La presente investigación resalta la importancia que tiene el uso eficiente de Energía en la temática de Producción más Limpia, identificando acciones que se han realizado en Nicaragua, Costa Rica y Chile. Se muestra la situación energética de cada país, evidenciado la importancia de la eficiencia energética, además de resaltar la legislación y la institucionalidad de esta temática. Igualmente, se presentan datos generales del contexto de cada país, lo que permite comprender su situación global.

Estudio y diseño de un sistema micro hidroeléctrico para generación y abastecimiento de energía eléctrica mediante energía renovable para una vivienda típica del sector de Sinincay perteneciente al Cantón Cuenca

OpenAIRE

Vásquez Huiracocha, Vinicio Rolando

2015-01-01

Para solucionar la falta de energía eléctrica para una vivienda que por su ubicación está distante de la red de distribución pero posee condiciones favorables para generar energía limpia y renovable con los beneficios económicos, ambientales, sociales y demás implícitos, favorecen para estudiar y construir una microcentral hidroeléctrica de agua fluyente a través de una turbina Pelton acoplada al generador de 2000 Vatios en frecuencia y voltaje nominales. Tras conexiones, protecciones y medic...

Evaluación energética industrial de las instalaciones textiles de Delltex Industrial S.A. planta Cumbayá aplicando la norma NTE INEN-ISO 50001:2012

OpenAIRE

Taipe Vilaña, Walter Edwin

2016-01-01

Este proyecto presenta la aplicación de la norma NTE INEN-ISO 50001:2012, en la realización de la evaluación energética de las instalaciones de Delltex Industrial S.A. ubicada en Cumbayá; la cual inicia con la esquematización del proceso productivo de la planta para construir los diagramas de flujo de proceso, insumos y energéticos; descrito el proceso de la planta, se realiza el balance global de energía mediante la caracterización del consumo con la identificación de los principales usuario...

Perspectivas de la situación energética mundial. Las oportunidades para Colombia

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Arturo Infante Villarreal

2007-05-01

Full Text Available Casi la cuarta parte de la energía que consume Estados Unidos proviene de petróleo importado y sólo el 6% se origina en fuentes renovables, aunque el país produce 20% de la polución ambiental mundial y tiene sólo 4% de la población total. Los biocombustibles son una fuente potencial de energía renovable para Estados Unidos, y el resto del mundo, porque tienen un balance energético y ambiental bastante favorable. Si las condiciones de precios son adecuadas para los productores de las materias primas, los biocombustibles también tienen un impacto social importante. Colombia tiene posibilidades de participar en los mercados nacionales e internacionales de los biocombustibles sustitutos, tanto de la gasolina como del diesel con etanol y biodiesel, respectivamente. La palma de aceite, la caña de azúcar y la yuca constituyen las materias primas con mayor potencial./ Almost one fourth of the energy consumed in the U.S. comes from imported oil and only 6% is produced from renewable sources despite the fact that the U.S. is responsible for 20% of the global pollution with barely 4% of the world population. Biofuels are a promising source of renewable energy for the United States and the rest of the world, with favorable energy and environmental balances. If price conditions are adequate for the basic input producers, biofuels will have an important social impact, as well. Colombia has the possibility to participate in the national and international biofuel substitution markets for gasoline and diesel with ethanol and biodiesel, respectively. Oil Palm, Sugar Cane and Yuca, are the raw materials with the best potential.

El coste energético de la desalinización en el programa A.G.U.A.

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Alberto del Villar García

2014-01-01

Full Text Available Tras la derogación del trasvase del Ebro por el Real Decreto 2/2004 y la promulgación de la Ley 11/2005 de modificación del Plan Hidrológico Nacional, se reorientó la política del agua para satisfacer las nuevas necesidades de agua en el arco mediterráneo peninsular por medio de la desalinización. Esta política se ha centrado en un conjunto de actuaciones a través del llamado Programa A.G.U.A. (Actuaciones para la Gestión y Utilización del Agua. Las actuaciones en materia de desalinización de dicho programa se han materializado en la construcción de 16 nuevas plantas desalinizadoras con una capacidad de producción de casi 350 hm3. Del conjunto de estas actuaciones, al menos 6 de ellas pretendían satisfacer, de manera parcial, las necesidades de agua de unas 244.000 hectáreas de regadío, con un volumen de unos 155,37 hm3. En 2008, el coste por metro cúbico estimado de producción, en las seis plantas destinadas a riego agrícola ascendía a 0,8634 €. El coste energético suponía aproximadamente un 52% de los costes de operación y mantenimiento, y un 39% de los costes totales (0,3373 €/m3. Este coste se estimó con una factura energética que recogía un precio de la energía en el entorno de 0,08 €/kwh. En 2012 el precio de la energía se sitúa por encima de 0,14 €/kwh, un 65% superior al calculado para 2008. Este incremento se traduce en un aumento de la factura por esta fuente de recursos calculado en unos 0,21 €/m3.

Modelización de materiales piezoeléctricos como generadores de energía

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Vázquez Rodríguez, M.

2012-02-01

Full Text Available This paper presents the method to determine electrical equivalent models of piezoelectric materials used as electric power generating elements. The models developed from the experimental results have been used to obtain the type, amount and optimal topological structure of semiconductor elements needed in the input stage of the power generation system, and its behaviour under variable power supply demand.

En este trabajo se presenta el estudio realizado para determinar los modelos eléctricos equivalentes de materiales de tipo piezoeléctrico, para evaluar su capacidad como elementos generadores de energía eléctrica. Los diferentes modelos desarrollados a partir de los resultados experimentales registrados, se han utilizado para obtener la estructura óptima de elementos semiconductores a utilizar en la etapa de entrada del sistema de generación y acumulación de energía eléctrica, teniendo en cuenta su morfología, tipo de semiconductor a utilizar y número necesario, así como su comportamiento ante una demanda variable de potencia a suministrar

Diseño e implantación de un sistema de gestión de la energía según ISO 50001 en una planta de montaje aeronáutico

OpenAIRE

Romera Benavente, Fernando

2015-01-01

El objeto del presente Proyecto Fin de Carrera consiste en diseñar, de forma que sea implantable, un Sistema de Gestión de la Energía UNE-EN-ISO 50001:2011 en la empresa aeronáutica líder UCAFLY Aerospace (de carácter ficticio), en su planta de Puerto Real (Cádiz), que será el primero de toda la compañía a nivel internacional. De este modo, la compañía podrá sistematizar la gestión de la energía, mejorar su desempeño energético a través de la eficiencia energética, reducir los ...

El nexo entre cambio climático y energía renovable en el Mercosur. Un análisis comparativo de las legislaciones de Argentina y Brasil

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Laura Casola

2017-12-01

Full Text Available El sector energético es uno de los principales contribuyentes al cambio climático debido a la combustión de hidrocarburos, por lo que la energía renovable se presenta como una alternativa para promover el desarrollo sustentable. En ese sentido, aplicando una metodología comparativa, este artículo analiza las regulaciones sobre cambio climático y energía renovable en Argentina y Brasil, considerados los dos Estados política y económicamente más fuertes del Mercosur, los cuales están especialmente afectados por el cambio climático. En esa lógica, se examina si los Estados priorizan el desarrollo sustentable o la seguridad energética, de qué manera las políticas del Mercosur influencian las decisiones nacionales, y si existen estándares comunes que posibiliten una futura integración regional en la materia.

Segurança energética e mudanças climáticas na União Europeia

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Giorgio Romano

2014-06-01

Full Text Available O estudo da economia política da energia é cada vez mais relevante para as Relações Internacionais em função do aumento da interdependência energética e da sua interação com os demais aspectos da agenda internacional, em particular as mudanças climáticas. Este trabalho pretende analisar os avanços e as dificuldades da política energética da União Europeia (UE. O objetivo é identificar os fatores que levaram a Comissão Europeia a articular, sobretudo a partir de 2005, um ativismo inédito na área de energia, apesar da inexistência de uma competência formal para o estabelecimento de uma política energética comum. Isso resultou em uma legislação europeia inovadora e ambiciosa, analisada e avaliada neste trabalho a partir de documentos oficiais, da literatura recente e de entrevistas qualitativas com cerca de vinte formuladores e analistas de política, realizadas em Bruxelas, em setembro de 2012. Ficou evidente que a discussão em torno da mudança climática alterou o olhar sobre a questão energética. O fato de a UE como um todo ser crescentemente deficitária no campo energético aumentou a relevância da questão da segurança e acabou também estimulando a busca de fontes alternativas, ao mesmo tempo em que condicionou suas relações externas, em particular com a Rússia. Houve avanços importantes, sobretudo a partir do estabelecimento de normas rígidas e mandatórias para os países-membros com o Pacto Energia-Clima que justificavam o papel de liderança que a UE estava assumindo nas negociações internacionais sobre o clima. A busca de respostas comunitárias e de convergência entre os objetivos relacionados às mudanças climáticas,àsegurança energéticaeàcompetividade econômica sofreu uma forte pressão com o impacto da crise global, depois de setembro de 2008. A crise evidenciou o ainda frágil arcabouço institucional que, diante do contexto de recessão, acabou reforçando tendências centrífugas em

Características relevantes de la simulación energética de viviendas unifamiliares

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García-Alvarado, R.

2014-03-01

Full Text Available Energy simulation systems allow analyzing the environmental quality and demand of buildings, but they must have reliable and proper procedures. This paper identifies relevant conditions of energy simulation systems for the study of single-family homes, based on the analysis of a dozen programs and various experiences in south central Chile. A review of capabilities was conducted, simulating the same case in all systems and making interviews with expert users. Besides it studied the incidence of background data and different strategies for analysis the environmental performance of housing. Revealing significant characteristics in the energy study of detached residential buildings. Finally it suggests reviewing certain conditions to ensure the effectiveness of the environmental analysis and subsequent actions.Los sistemas de simulación energética de edificios permiten analizar la calidad y demanda ambiental de las construcciones, pero deben contar con procedimientos fiables y pertinentes. Este artículo identifica condiciones relevantes de la simulación energética de viviendas unifamiliares, basado en el análisis de una docena de programas y distintas experiencias en el centro sur de Chile. Desarrollando una revisión de capacidades de los sistemas, a través de la simulación de una misma vivienda y entrevistas a usuarios expertos. Además de estudiar incidencias de los antecedentes y distintas estrategias de análisis para el mejoramiento ambiental de viviendas. Revelando características significativas para el estudio energético de construcciones habitacionales aisladas. Finalmente sugiere revisar ciertas condiciones de los sistemas para asegurar la efectividad de los análisis ambientales y de las acciones subsecuentes.

On the sub-maximal yield and photo-electric stimulation of chlorophyll a fluorescence in single turnover excitations in plant cells

NARCIS (Netherlands)

Vredenberg, W.J.; Rensen, van J.J.S.; Rodrigues, G.C.

2006-01-01

A set of expressions is derived which quantifies the chlorophyll fluorescence yield in terms of rate constants of primary light reactions of PSII, the fraction of open and semi-open RCs and of the electric field sensed by the RC in the thylakoid membrane. The decay kinetics of the chlorophyll

Stochastic Fermi Energization of Coronal Plasma during Explosive Magnetic Energy Release

Science.gov (United States)

Pisokas, Theophilos; Vlahos, Loukas; Isliker, Heinz; Tsiolis, Vassilis; Anastasiadis, Anastasios

2017-02-01

The aim of this study is to analyze the interaction of charged particles (ions and electrons) with randomly formed particle scatterers (e.g., large-scale local “magnetic fluctuations” or “coherent magnetic irregularities”) using the setup proposed initially by Fermi. These scatterers are formed by the explosive magnetic energy release and propagate with the Alfvén speed along the irregular magnetic fields. They are large-scale local fluctuations (δB/B ≈ 1) randomly distributed inside the unstable magnetic topology and will here be called Alfvénic Scatterers (AS). We constructed a 3D grid on which a small fraction of randomly chosen grid points are acting as AS. In particular, we study how a large number of test particles evolves inside a collection of AS, analyzing the evolution of their energy distribution and their escape-time distribution. We use a well-established method to estimate the transport coefficients directly from the trajectories of the particles. Using the estimated transport coefficients and solving the Fokker-Planck equation numerically, we can recover the energy distribution of the particles. We have shown that the stochastic Fermi energization of mildly relativistic and relativistic plasma can heat and accelerate the tail of the ambient particle distribution as predicted by Parker & Tidman and Ramaty. The temperature of the hot plasma and the tail of the energetic particles depend on the mean free path (λsc) of the particles between the scatterers inside the energization volume.

Stochastic Fermi Energization of Coronal Plasma during Explosive Magnetic Energy Release

Energy Technology Data Exchange (ETDEWEB)

Pisokas, Theophilos; Vlahos, Loukas; Isliker, Heinz; Tsiolis, Vassilis [Department of Physics, Aristotle University of Thessaloniki GR-52124 Thessaloniki (Greece); Anastasiadis, Anastasios [Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens GR-15236 Penteli (Greece)

2017-02-01

The aim of this study is to analyze the interaction of charged particles (ions and electrons) with randomly formed particle scatterers (e.g., large-scale local “magnetic fluctuations” or “coherent magnetic irregularities”) using the setup proposed initially by Fermi. These scatterers are formed by the explosive magnetic energy release and propagate with the Alfvén speed along the irregular magnetic fields. They are large-scale local fluctuations ( δB / B ≈ 1) randomly distributed inside the unstable magnetic topology and will here be called Alfvénic Scatterers (AS). We constructed a 3D grid on which a small fraction of randomly chosen grid points are acting as AS. In particular, we study how a large number of test particles evolves inside a collection of AS, analyzing the evolution of their energy distribution and their escape-time distribution. We use a well-established method to estimate the transport coefficients directly from the trajectories of the particles. Using the estimated transport coefficients and solving the Fokker–Planck equation numerically, we can recover the energy distribution of the particles. We have shown that the stochastic Fermi energization of mildly relativistic and relativistic plasma can heat and accelerate the tail of the ambient particle distribution as predicted by Parker and Tidman and Ramaty. The temperature of the hot plasma and the tail of the energetic particles depend on the mean free path ( λ {sub sc}) of the particles between the scatterers inside the energization volume.

Una propuesta para desarrollar en el alumno de secundaria una visión unificada de la física a partir de la energía

Directory of Open Access Journals (Sweden)

Pérez-Landazábal, Mª.C.

2006-04-01

Full Text Available En este trabajo se presenta una propuesta de enseñanza de la Física en la Educación Secundaria Obligatoria centrada en la energía. El estudio, que toma como referencia el enfoque constructivista del aprendizaje, presenta el diseño de los materiales curriculares, así como su aplicación y evaluación en aulas de secundaria. Una exploración inicial de los conocimientos previos de los alumnos sobre la energía constituye la base de los materiales desarrollados, que incluyen una unidad didáctica introductoria y otras tres unidades dedicadas a la energía eléctrica, interna y mecánica.

Assembly of Photosynthetic Antenna Protein Complexes from Algae for Development of Nano-biodevice and Its Fuelization

Science.gov (United States)

2013-05-20

bacterial photosynthesis . The structure of the reaction center (RC, the first membrane protein to have its structure determined to high resolution...Introduction] In a bacterial photosynthesis , light-harvesting complex 2 (LH2) and lightharvesting-reaction center complex (LH1-RC) play the key...Artificial Leaf 6CO2 + 6H2O C6H12O6 (Glucose) +6O2 Natural Leaf Photosynthesis and redox proteins are well-organized into thylakoid membrane in natural leaf

La situación energética en el Pacto Andino

OpenAIRE

Centro de Estudios Sudamericanos

2008-01-01

Los países de la región han venido modernizando sus sectores energéticos y han adoptado enfoques similares en cuanto a objetivos generales como la búsqueda de la eficiencia mediante mecanismos de mercado donde ello sea posible; la tendencia al alejamiento del Estado de actividades puramente empresariales y su focalización en los temas de regulación y control; la puesta en marcha de políticas transparentes que promuevan la competencia; y la participación de inversionistas privados, etc. No obs...

Modeling the Energization and Eruption of Flux Ropes and Sheared Arcades

Science.gov (United States)

Linton, Mark G.

2016-10-01

Solar magnetic eruptions are dramatic sources of solar activity, and dangerous sources of space weather hazards. Observations of the solar photosphere and overlying atmosphere by the Solar Dynamics Observatory have given us new views, measurements, and modeling constraints for understanding these eruptions. This presentation will review the current state of the art in modeling the energization and eruption of sheared magnetic arcades and of magnetic flux ropes in the corona, and will review the critical role that observations play in the motivation, development, and application of these models.

Análisis del potencial energético solar en la Región Caribe para el diseño de un sistema fotovoltaico

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Adalberto José Ospino Castro

2010-01-01

Full Text Available La utilización de los rayos solares para la generación de energía eléctrica se ha incrementando en los últimos años, debido principalmente al cambio climático, por tanto es importante demostrar que para la región Caribe existe potencial energético derivado del aprovechamiento de la radiación solar para la utilización de sistemas renovables de energía. Para el proyecto se toma como muestra para el estudio del potencial energético el departamento del Atlántico basado en los mapas de radiación solar de Colombia diseñados por el IDEAM, ya que los mismos permiten obtener parámetros de construcción, y viabilidad técnica. Como resultado se obtiene una metodología que permite establecer los parámetros a tener en cuenta para el desarrollo de los sistemas renovables fotovoltaicos y se realiza a futuro el estudio de viabilidad técnico-económico de implementación de estos sistemas seleccionando el área adecuada obteniendo la tecnología adecuada a las condiciones de la región.

D0 Central Tracking Solenoid Energization, Controls, Interlocks and Quench Protection Operating Procedures

International Nuclear Information System (INIS)

Hance, R.

1998-01-01

This procedure is used when it is necessary to operate the solenoid energization, controls, interlocks and quench detection system. Note that a separate procedure exists for operating the solenoid 'cryogenic' systems. Only D0 Control Room Operators or the Project Electrical Engineer are qualified to execute these procedures or operate the solenoid system. This procedure assumes that the operator is familiar with using the Distributed Manufacturing Automation and Control Software (DMACS).

Transverse ion energization and low-frequency plasma waves in the mid-altitude auroral zone: A case study

International Nuclear Information System (INIS)

Peterson, W.K.; Shelley, E.G.; Boardsen, S.A.; Gurnett, D.A.; Ledley, B.G.; Sugiura, M.; Moore, T.E.; Waite, J.H.

1988-01-01

The transport of ions from the ionosphere to the magnetosphere requires that ions acquire significant energy in directions both transverse and parallel to the magnetic field. There is a considerable body of experimental evidence that shows that transverse energization occurs over a wide range of altitudes on auroral field lines. Many recent analytical and simulation studies have addressed the microphysics involved in transverse ion energization. There are, however, remarkably few published high-resolution plasma and plasma wave observations obtained in the mid-altitude auroral region available to compare with the analytical and simulation studies. Several hundred hours of high-resolution plasma data obtained from the Dynamics Explorer 1 satellite have been surveyed. A wide variety of plasma environments that are difficult to simply characterize were found. We present here a comprehensive set of high-sensitivity, high-resolution plasma wave, ion, and magnetometer data obtained from an evening auroral zone crossing at r/R/sub E/∼3. The total density, thermal structure, and composition of the plasma in this representative interval varied rapidly, as did the character (mode) of low-frequency plasma waves observed. We did not find an unambiguous particle and wave signature of local transverse ion energization, but we did frequently find intervals where local transverse ion heating was consistent with the observations. We also found a downward flowing ion distribution that occurred simultaneously with a region of intense plasma wave emissions primarily below the lower hybrid resonance frequency. copyright American Geophysical Union 1988

Model of taking of decisions for energization of isolated areas not interconnected

International Nuclear Information System (INIS)

Smith, Ricardo; Jaramillo, Patricia; Angel, William; Henao, Felipe

2003-01-01

In the word, particularly in developing countries, a big part of the population lives in isolated areas, which are, in most of the cases, poor. That is why governments and NGOs, make efforts to formulate policies, plans and programs in order to improve the quality of life and promote the economic development in those regions. However, most of those programs are not successful. One of the main causing factors of this problem is the decision maker's lack of proper methodologies that support them in the decision process. In this context, we propose some methodologies based in a multicriteria decision theory in order to solve two basic related problems: the first one is how to choose the most suitable and satisfactory technology for supply energy to an isolated area; the second one is how to order by priority a set of communities that are consider in a national or regional energization plan. The proposed patterns allow handling with problems where the consideration o many objectives and many decision makers in the process are necessary and with problems where part of the information is unknown or not precisely defined. With these methodologies, the responsible governmental entities in charge of the energization of a country would make less subjective energy plans with better solutions in terms of social, economic, environmental and technologic aspects

Model of taking of decisions for energization of isolated areas not interconnected

International Nuclear Information System (INIS)

Smith, Ricardo; Jaramillo, Patricia; Angel William; Henao, Felipe

2003-01-01

In the word, particularly in developing countries, a big part of the population lives in isolated areas, which are, in most of the cases, poor. That is why governments and NGO make efforts to formulate policies, plans and programs in order to improve the quality of life and promote the economic development in those regions. However, most of those programs are not successful. One of the main causing factors of this problem is the decision maker's lack of proper methodologies that support them in the decision process. In this context, we propose some methodologies based in a multicriteria decision theory in order to solve two basic related problems: the first one is how to choose the most suitable and satisfactory technology for supply energy to an isolated area; the second one is how to order by priority a set of communities that are consider in a national or regional energization plan. The proposed patterns allow handling with problems where the consideration of many objectives and many decision makers in the process are necessary and with problems where part of the information is unknown or not precisely defined. With these methodologies, the responsible governmental entities - in charge of the energization of a country would make less subjective energy plans with better solutions in terms of social, economic, environmental and technologic aspects

Energization of electrons in a plasma beam entering a curved magnetic field

International Nuclear Information System (INIS)

Brenning, N.; Lindberg, L.; Eriksson, A.

1980-09-01

Earlier experiments have indicated that suprathermal electrons appear when a collisionless plasma flowing along a magnetic field enters a region where the magnetic field is curved. In the present investigation newly developed methods of He-spectroscopy based on the absolute intensities of the He I 3889 A and He II 4686 A lines are utilized to study the electron temperature and to estimate the population of non-thermal electrons. The density of helium added for the diagnostic purpose is so low that the flow is not disturbed. It is found that the intrusion of the plasma into a curved or transverse field gives rise to a slight increase (15-20%) in the electron temperature and a remarkable increase in the fraction of non-thermal (>100 eV) electrons from below 1% to as much as 20-25% of the total electron population. There are also indications that the energization of electrons is particularly efficient on that side of the plasma beam which becomes polarized to a positive potential when entering the curved field. The experiments are confined to the case of weak magnetic field, i.e. only the electrons are magnetically confined. New details of the electric field and potential structure are presented and discussed. Electric field components parallel to the magnetic field are likely to energize the electrons, probably through the run-away phenomenon. (Auth.)

Balance de nitrógeno y digestibilidad energética en ratas alimentadas con manteca de freidura

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Jiménez, S.

1992-06-01

Full Text Available This study was carried out during 90 days in order to know the effect of frying lard on the energy digestibility and nitrogen bioavailability. A significant decrease occurred on energy utilization of the diets prepared with frying lard (52 frying times. Nitrogen bioutilization on growing rats was also affected.

Se realiza un estudio de 90 días de duración en ratas con el fin de conocer posibles efectos de las grasas de freidura sobre el coeficiente de digestibilidad energética y la biodisponibilidad del nitrógeno. Se observó una disminución de la utilización de la energía de la dieta con el consumo reiterado de grasas con 52 freiduras y se encontró afectada la bioutilización del nitrógeno del organismo en crecimiento.

Estimativa das necessidades energéticas em pacientes com doença renal crônica Estimating the energy requirement of chronic kidney disease patients

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Juliana Cordeiro Dias Rodrigues

2013-02-01

Full Text Available Estabelecer as necessidades energéticas de pacientes com doença renal crônica é importante para que se possam tratar os distúrbios nutricionais encontrados nessa população. Segundo os guias de condutas voltados ao cuidado nutricional de pacientes com essa doença, a recomendação energética pode variar entre 30 e 40kcal/kg/dia. Contudo, trabalhos que avaliaram os componentes do gasto energético nos pacientes com doença renal crônica sugerem que as necessidades energéticas dessa população podem diferir do valor recomendado acima, a depender da condição clínica (presença de comorbidades, da modalidade de tratamento empregado e do nível de atividade física. Dessa forma, o presente trabalho tem como objetivo fazer uma revisão dos estudos sobre o gasto energético de pacientes com doença renal crônica, com o intuito de abordar as seguintes questões: (1 as atuais recomendações de energia para pacientes com doença renal crônica estão adequadas? (2 qual equação de predição poderia ser empregada para estimar as necessidades energéticas desse grupo de pacientes? Assim, esta revisão busca auxiliar o nutricionista ao estimar as necessidades energéticas de pacientes com doença renal crônica.Estimating the energy requirement of patients with chronic kidney disease is highly important for treating the nutritional disorders often seen in this population. According to the specific guidelines for patients with chronic kidney disease, the currently recommended daily energy intake varies from 30 to 40kcal/kg/day. However, studies that investigated energy expenditure components of patients with chronic kidney disease suggested that the energy requirement may differ from the one proposed earlier, depending on overall clinical condition (i.e. presence of comorbidities, treatment modality and level of physical activity. With this perspective in mind, the present study aims to review the studies assessing energy expenditure

Posibilidades de Generación de Energía en base al Potencial Geotérmico de la Península de Santa Elena.

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Hernán E. Poveda Z.

2015-10-01

En este estudio, proponemos la posibilidad de utilizar esta energía natural para transformarla en electricidad. Aprovechando las condiciones de algunos de los afloramientos de manantiales de agua caliente y volcanes de lodo que existen en la provincia. Para lo cual hemos propuesto al Instituto Austriaco de tecnología, su asesoría y asistencia para proponer un proyecto al ministerio de electrificación y energías renovables.

Simulación de Redes de Sensores Inalámbricos: un Modelo Energético a Nivel de Nodo-Sensor Bajo las Especificaciones Ieee 802.15.4tm y Zigbee

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Milton Osvaldo Amarillo Rojas

2015-10-01

Full Text Available Este artículo presenta el desarrollo de un modelo de simulación para una red de sensores inalámbricos que se rige por las especificaciones IEEE 802.15.4 y ZigBee y que utiliza la configuración de la beacon habilitada. El modelo de simulación también implementa un modelo de consumo de energía para los tres tipos de nodossensores de la red (Coordinador ZigBee, Router y Dispositivo Final. El principal aporte de este trabajo radica en que por medio de la simulación se puede estimar el consumo de energía de un nodo-sensor y, de esta forma, analizar el consumo de energía de cada uno de los tipos del mismo. Así mismo, al poder estimar el consumo de energía del nodo-sensor, también se puede estimar su tiempo de vida. Por último, se analiza la razón, por la cual, el consumo de energía de los nodos es inversamente proporcional a la latencia de los datos dentro de la red.

Avaliação energética da empresa RENOPEL

OpenAIRE

Silva, Fábio André Pereira da

2016-01-01

A presente dissertação insere-se no âmbito da unidade curricular “Dissertação” do 2º ano de Mestrado de Engenharia Eletrotécnica- Sistemas Elétricos de Energia, tendo sido realizada na empresa Renopel que é uma Lavandaria Industrial que se situa na Maia. O objetivo desta dissertação era a realização de uma Avaliação energética (AE) à Renopel que tem elevados consumos de energia, tanto a nível térmico como elétrico e no ano de 2015 consumiu aproximadamente 800 MWh em gás natural...

Comparación de recursos energéticos residenciales en las ciudades de Valdivia (Chile) y Bariloche (Argentina): precios y consumos

OpenAIRE

Schueftan, Alejandra; Gonzalez, Alejandro Daniel

2016-01-01

Se investigó la disponibilidad de recursos energéticos en el sector residencial de Valdivia en Chile y de Bariloche en Argentina. Se compararon los precios de los recursos y los consumos promedio. En ambos casos, el requerimiento principal es en calefacción, para la cual en Valdivia en su mayoría se usa leña, y en Bariloche gas natural, en ambos casos con los precios relativos menores. Por unidad de energía y de salario el gas natural en Bariloche resulta 12 veces más barato que la leña e...

On the mechanism of sulfite activation of chloroplast thylakoid ATPase and the relation of ADP tightly bound at a catalytic site to the binding change mechanism

International Nuclear Information System (INIS)

Du, Z.; Boyer, P.D.

1990-01-01

Washed chloroplast thylakoid membranes upon exposure to [ 3 H]ADP retain in tightly bound [ 3 H]ADP on a catalytic site of the ATP synthase. The presence of sufficient endogenous or added Mg 2+ results in an enzyme with essentially no ATPase activity. Sulfite activates the ATPase, and many molecules of ATP per synthase can be hydrolyzed before most of the bound [ 3 H]ADP is released, a result interpreted as indicating that the ADP is not bound at a site participating in catalysis by the sulfite-activated enzyme. The authors present evidence that this is not the case. The Mg 2+ - and ADP-inhibited enzyme when exposed to MgATP and 20-100 mM sulfite shows a lag of about 1 min at 22 degree C and of about 15 s at 37 degree C before reaching the same steady-state rate as attained with light-activated ATPase that has not been inhibited by Mg 2+ and ADP. The lag is not eliminated if the enzyme is exposed to sulfite prior to MgATP addition, indicating that ATPase turnover is necessary for the activation. The release of most of the bound [ 3 H]ADP parallels the onset of ATPase activity, although some [ 3 H]ADP is not released even with prolonged catalytic turnover and may be on poorly active or inactive enzyme or at noncatalytic sites. The results are consistent with most of the tightly bound [ 3 H]ADP being at a catalytic site and being replaced as this Mg 2+ - and ADP-inhibited site regains equivalent participation with other catalytic sites on the activated enzyme. The sulfite activation can be explained by sulfite combination at a P i binding site of the enzyme-ADP-Mg 2+ complex to give a form more readily activated by ATP binding at an alternative site

Consumo de bebidas energéticas, alcohólicas y azucaradas en jóvenes universitarios de la frontera México-USA

OpenAIRE

Gómez-Miranda, Luis Mario; Bacardí-Gascón, Montserrat; Caravalí-Meza, Nuris Yohana; Jiménez-Cruz, Arturo

2015-01-01

Introducción: El consumo de bebidas azucaradas, energéticas y alcohólicas en universitarios puede ser un riesgo para la salud. Objetivo: Determinar el consumo de bebidas azucaradas, energéticas, y alcohólicas y compararlo con el estado del IMC en universitarios. Metodología: Se evaluaron estudiantes de segundo y tercer año de la UABC. Se midieron el peso, la talla y la circunferencia de cintura, y se calculó el IMC. Se aplicó un cuestionario sobre consumo de 19 bebidas. Resultados: Participar...

Potencial de secado de yuca con aire natural y energía solar

Directory of Open Access Journals (Sweden)

Alfonso Parra Coronado

1990-01-01

Full Text Available En este trabajo se presentan los resultados de estudios del potencial de secado de productos agropecuarios con aire natural y energía solar de regiones tropicales, considerando el caso específico de la yuca. La evaluación del potencial de secado de una región se basa en el uso de un programa de computador  Simulación matemática, mediante el cual se obtienen los valores del caudal mínimo de aire requerido para secar el producto antes que éste alcance un nivel de deterioro preestablecido. Otros elementos metodológicos incluyen: manejo de la información meteorológica, mes crítico, patrón de agitación del producto, hora de iniciación del secado, patrón de operación del ventilador, uso de calor suplementario (energía solar e interpretación de los resultados con el fin de optimizar el sistema. Se presentan mapas para Colombia de líneas isocaudales e isoáreas de colector solar plano, con base en los cuales se puede obtener fácilmente la información requerida para el diseño de sistemas de secado de yuca a baja temperatura.

Energías renovables y desarrollo económico. Un análisis para España y las grandes economías europeas

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María Ángeles Caraballo Pou

2017-01-01

Full Text Available Antecedentes: Este trabajo evalúa la sostenibilidad del modelo de desarrollo económico español en el periodo 1980-2010. Asimismo, realiza un análisis comparativo con las grandes economías europeas: Alemania, Francia, Italia y Reino Unido.Metodología: Para alcanzar el objetivo del trabajo se han empleado técnicas de cointegración. Mediante estas técnicas se analiza la relación a largo plazo del consumo de energías renovables y no renovables con el desarrollo económico y la contaminación en el periodo 1980-2010. Tras un proceso de selección de variables, para España se ha utilizado el Producto Interno Bruto (PIB y la Formación Bruta de Capital, para medir el crecimiento, el Índice de Desarrollo Humano y el Capital Social, para el desarrollo, las emisiones de CO2 para la contaminación, el consumo de energía renovable en el sistema eléctrico y el consumo de petróleo para el consumo de energía renovable y no renovable, respectivamente. En segundo lugar, se han comparado los resultados obtenidos para la economía española con las cuatro economías más grandes de la Unión Europea: Alemania, Francia, Italia y Reino Unido. Dada la disponibilidad de datos, para estos países se ha excluido del análisis la Formación Bruta de Capital y el Índice de Desarrollo Humano.Resultados: En primer lugar, para los cinco países analizados se comprueba un impacto positivo del consumo de energía renovable y no renovable sobre el crecimiento y el desarrollo, con un impacto mayor de las energías no renovables. Para los tres países en los que se han incluido las emisiones de CO2 (España, Francia y Reino Unido, el efecto reductor de las renovables sobre las emisiones de CO2 es menor que el efecto contaminante de las no renovables. En segundo lugar, para España, Alemania y Francia se aprecia un proceso de retroalimentación entre el consumo de no renovables, el crecimiento y el desarrollo, que no se observa con el consumo de energ