Sample records for exchange factor epac

  1. Epac : effectors and biological functions

    NARCIS (Netherlands)

    Roscioni, Sara S.; Elzinga, Carolina R. S.; Schmidt, Martina

    Epac1 (also known as cAMP-GEF-I) and Epac2 (also known as cAMP-GEF-II) are cyclic AMP-activated guanine nucleotide exchange factors for Ras-like GTPases. Since their discovery about 10 years ago, it is now accepted that Epac proteins are novel cAMP sensors that regulate several pivotal cellular

  2. Nerve growth factor mediates a switch in intracellular signaling for PGE2-induced sensitization of sensory neurons from protein kinase A to Epac. (United States)

    Vasko, Michael R; Habashy Malty, Ramy; Guo, Chunlu; Duarte, Djane B; Zhang, Yihong; Nicol, Grant D


    We examined whether nerve growth factor (NGF), an inflammatory mediator that contributes to chronic hypersensitivity, alters the intracellular signaling that mediates the sensitizing actions of PGE2 from activation of protein kinase A (PKA) to exchange proteins directly activated by cAMP (Epacs). When isolated sensory neurons are grown in the absence of added NGF, but not in cultures grown with 30 ng/ml NGF, inhibiting protein kinase A (PKA) activity blocks the ability of PGE2 to augment capsaicin-evoked release of the neuropeptide CGRP and to increase the number of action potentials (APs) evoked by a ramp of current. Growing sensory neurons in culture in the presence of increasing concentrations of NGF increases the expression of Epac2, but not Epac1. An intradermal injection of complete Freund's adjuvant into the rat hindpaw also increases the expression of Epac2, but not Epac1 in the dorsal root ganglia and spinal cord: an effect blocked by intraplantar administration of NGF antibodies. Treating cultures grown in the presence of 30 ng/ml NGF with Epac1siRNA significantly reduced the expression of Epac1, but not Epac2, and did not block the ability of PGE2 to augment capsaicin-evoked release of CGRP from sensory neurons. Exposing neuronal cultures grown in NGF to Epac2siRNAreduced the expression of Epac2, but not Epac1 and prevented the PGE2-induced augmentation of capsaicin and potassium-evoked CGRP release in sensory neurons and the PGE2-induced increase in the number of APs generated by a ramp of current. In neurons grown with no added NGF, Epac siRNAs did not attenuate PGE2-induced sensitization. These results demonstrate that NGF, through increasing Epac2 expression, alters the signaling cascade that mediates PGE2-induced sensitization of sensory neurons, thus providing a novel mechanism for maintaining PGE2-induced hypersensitivity during inflammation.

  3. Epac and the cardiovascular system

    NARCIS (Netherlands)

    Schmidt, Martina; Sand, Carsten; Jakobs, Karl H.; Michel, Martin C.; Weernink, Paschal A. Oude

    Exchange protein activated by cyclic AMP (Epac) - a cyclic AMP-activated guanine nucleotide exchange factor for Ras-like GTPases - has emerged as a novel mediator of pivotal processes in the cardiovascular system, including cellular calcium handling, hypertrophy, integrin-mediated cell adhesion,

  4. EPAC expression and function in cardiac fibroblasts and myofibroblasts

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    Olmedo, Ivonne; Muñoz, Claudia; Guzmán, Nancy; Catalán, Mabel; Vivar, Raúl; Ayala, Pedro; Humeres, Claudio; Aránguiz, Pablo [Departamento de Química Farmacológica y Toxicológica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile (Chile); García, Lorena [Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile (Chile); Velarde, Victoria [Departamento de Ciencias Fisiológicas, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile (Chile); Díaz-Araya, Guillermo, E-mail: [Departamento de Química Farmacológica y Toxicológica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile (Chile)


    In the heart, cardiac fibroblasts (CF) and cardiac myofibroblasts (CMF) are the main cells responsible for wound healing after cardiac insult. Exchange protein activated by cAMP (EPAC) is a downstream effector of cAMP, and it has been not completely studied on CF. Moreover, in CMF, which are the main cells responsible for cardiac healing, EPAC expression and function are unknown. We evaluated in both CF and CMF the effect of transforming growth factor β1 (TGF-β1) on EPAC-1 expression. We also studied the EPAC involvement on collagen synthesis, adhesion, migration and collagen gel contraction. Method: Rat neonatal CF and CMF were treated with TGF-β1 at different times and concentrations. EPAC-1 protein levels and Rap1 activation were measured by western blot and pull down assay respectively. EPAC cellular functions were determined by adhesion, migration and collagen gel contraction assay; and collagen expression was determined by western blot. Results: TGF-β1 through Smad and JNK significantly reduced EPAC-1 expression in CF, while in CMF this cytokine increased EPAC-1 expression through ERK1/2, JNK, p38, AKT and Smad3. EPAC activation was able to induce higher Rap1-GTP levels in CMF than in CF. EPAC and PKA, both cAMP effectors, promoted CF and CMF adhesion on fibronectin, as well as CF migration; however, this effect was not observed in CMF. EPAC but not PKA activation mediated collagen gel contraction in CF, while in CMF both PKA and EPAC mediated collagen gel contraction. Finally, the EPAC and PKA activation reduced collagen synthesis in CF and CMF. Conclusion: TGF-β1 differentially regulates the expression of EPAC in CF and CMF; and EPAC regulates differentially CF and CMF functions associated with cardiac remodeling. - Highlights: • TGF-β1 regulates EPAC-1 expression in cardiac fibroblast and myofibroblast. • Rap-1GTP levels are higher in cardiac myofibroblast than fibroblast. • EPAC-1 controls adhesion, migration and collagen synthesis in cardiac

  5. Exchange Protein Activated by Cyclic AMP 2 (Epac2) Plays a Specific and Time-Limited Role in Memory Retrieval

    NARCIS (Netherlands)

    Ostroveanu, Anghelus; van der Zee, Eddy A.; Eisel, Ulrich L. M.; Schmidt, Martina; Nijholt, Ingrid M.


    Knowledge on the molecular mechanisms involved in memory retrieval is limited due to the lack of tools to study this stage of the memory process. Here we report that exchange proteins activated by cAMP (Epac) play a surprisingly specific role in memory retrieval. Intrahippocampal injection of the

  6. Epac activation sensitizes rat sensory neurons through activation of Ras. (United States)

    Shariati, Behzad; Thompson, Eric L; Nicol, Grant D; Vasko, Michael R


    Guanine nucleotide exchange factors directly activated by cAMP (Epacs) have emerged as important signaling molecules mediating persistent hypersensitivity in animal models of inflammation, by augmenting the excitability of sensory neurons. Although Epacs activate numerous downstream signaling cascades, the intracellular signaling which mediates Epac-induced sensitization of capsaicin-sensitive sensory neurons remains unknown. Here, we demonstrate that selective activation of Epacs with 8-CPT-2'-O-Me-cAMP-AM (8CPT-AM) increases the number of action potentials (APs) generated by a ramp of depolarizing current and augments the evoked release of calcitonin gene-related peptide (CGRP) from isolated rat sensory neurons. Internal perfusion of capsaicin-sensitive sensory neurons with GDP-βS, substituted for GTP, blocks the ability of 8CPT-AM to increase AP firing, demonstrating that Epac-induced sensitization is G-protein dependent. Treatment with 8CPT-AM activates the small G-proteins Rap1 and Ras in cultures of sensory neurons. Inhibition of Rap1, by internal perfusion of a Rap1-neutralizing antibody or through a reduction in the expression of the protein using shRNA does not alter the Epac-induced enhancement of AP generation or CGRP release, despite the fact that in most other cell types, Epacs act as Rap-GEFs. In contrast, inhibition of Ras through expression of a dominant negative Ras (DN-Ras) or through internal perfusion of a Ras-neutralizing antibody blocks the increase in AP firing and attenuates the increase in the evoked release of CGRP induced by Epac activation. Thus, in this subpopulation of nociceptive sensory neurons, it is the novel interplay between Epacs and Ras, rather than the canonical Epacs and Rap1 pathway, that is critical for mediating Epac-induced sensitization. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Epac activation sensitizes rat sensory neurons via activation of Ras (United States)

    Shariati, Behzad; Thompson, Eric L.; Nicol, Grant D.; Vasko, Michael R.


    Guanine nucleotide exchange factors directly activated by cAMP (Epacs) have emerged as important signaling molecules mediating persistent hypersensitivity in animal models of inflammation, by augmenting the excitability of sensory neurons. Although Epacs activate numerous downstream signaling cascades, the intracellular signaling which mediates Epac-induced sensitization of capsaicin-sensitive sensory neurons remains unknown. Here, we demonstrate that selective activation of Epacs with 8-CPT-2′-O-Me-cAMP-AM (8CPT-AM) increases the number of action potentials (APs) generated by a ramp of depolarizing current and augments the evoked release of calcitonin gene-related peptide (CGRP) from isolated rat sensory neurons. Internal perfusion of capsaicin-sensitive sensory neurons with GDP-βS, substituted for GTP, blocks the ability of 8CPT-AM to increase AP firing, demonstrating that Epac-induced sensitization is G-protein dependent. Treatment with 8CPT-AM activates the small G-proteins Rap1 and Ras in cultures of sensory neurons. Inhibition of Rap1, by internal perfusion of a Rap1-neutralizing antibody or through a reduction in the expression of the protein using shRNA does not alter the Epac-induced enhancement of AP generation or CGRP release, despite the fact that in most other cell types, Epacs act as Rap-GEFs. In contrast, inhibition of Ras through expression of a dominant negative Ras (DN-Ras) or through internal perfusion of a Ras-neutralizing antibody blocks the increase in AP firing and attenuates the increase in the evoked release of CGRP induced by Epac activation. Thus, in this subpopulation of nociceptive sensory neurons, it is the novel interplay between Epacs and Ras, rather than the canonical Epacs and Rap1 pathway, that is critical for mediating Epac-induced sensitization. PMID:26596174

  8. Exchange Protein Directly Activated by cAMP (EPAC) Regulates Neuronal Polarization through Rap1B

    NARCIS (Netherlands)

    Munoz-Llancao, Pablo; Henriquez, Daniel R.; Wilson, Carlos; Bodaleo, Felipe; Boddeke, Erik W.; Lezoualc'h, Frank; Schmidt, Martina; Gonzalez-Billault, Christian


    Acquisition of neuronal polarity is a complex process involving cellular and molecular events. The second messenger cAMP is involved in axonal specification through activation of protein kinase A. However, an alternative cAMP-dependent mechanism involves the exchange protein directly activated by

  9. Epac-rap signaling reduces oxidative stress in the tubular epithelium

    NARCIS (Netherlands)

    Stokman, Geurt; Qin, Yu; Booij, Tijmen H.; Ramaiahgari, Sreenivasa; Lacombe, Marie; Dolman, M. Emmy M.; Van Dorenmalen, Kim M.A.; Teske, Gwendoline J.D.; Florquin, Sandrine; Schwede, Frank; Van De Water, Bob; Kok, Robbert J.; Price, Leo S.


    Activation of Rap1 by exchange protein activated by cAMP (Epac) promotes cell adhesion and actin cytoskeletal polarization. Pharmacologic activation of Epac-Rap signaling by the Epac-selective cAMP analog 8-pCPT-2′-O-Me-cAMP during ischemia-reperfusion (IR) injury reduces renal failure and

  10. Cyclic AMP (cAMP)-mediated stimulation of adipocyte differentiation requires the synergistic action of Epac- and cAMP-dependent protein kinase-dependent processes

    DEFF Research Database (Denmark)

    Petersen, Rasmus Koefoed; Madsen, Lise; Pedersen, Lone Møller


    Cyclic AMP (cAMP)-dependent processes are pivotal during the early stages of adipocyte differentiation. We show that exchange protein directly activated by cAMP (Epac), which functions as a guanine nucleotide exchange factor for the Ras-like GTPases Rap1 and Rap2, was required for cAMP-dependent ......Cyclic AMP (cAMP)-dependent processes are pivotal during the early stages of adipocyte differentiation. We show that exchange protein directly activated by cAMP (Epac), which functions as a guanine nucleotide exchange factor for the Ras-like GTPases Rap1 and Rap2, was required for c......AMP-dependent stimulation of adipocyte differentiation. Epac, working via Rap, acted synergistically with cAMP-dependent protein kinase (protein kinase A [PKA]) to promote adipogenesis. The major role of PKA was to down-regulate Rho and Rho-kinase activity, rather than to enhance CREB phosphorylation. Suppression of Rho......-kinase impaired proadipogenic insulin/insulin-like growth factor 1 signaling, which was restored by activation of Epac. This interplay between PKA and Epac-mediated processes not only provides novel insight into the initiation and tuning of adipocyte differentiation, but also demonstrates a new mechanism of c...

  11. The role of exchange protein directly activated by cyclic AMP 2-mediated calreticulin expression in the decidualization of human endometrial stromal cells. (United States)

    Kusama, Kazuya; Yoshie, Mikihiro; Tamura, Kazuhiro; Nakayama, Takahiro; Nishi, Hirotaka; Isaka, Keiichi; Tachikawa, Eiichi


    Decidualization of human endometrial stromal cells (ESCs) accompanied by the production of prolactin (PRL) and IGF-binding protein (IGFBP) 1 and rounded-cell morphology is indispensable for the establishment and maintenance of pregnancy. Protein kinase A (PKA)-mediated cAMP signaling is known to be crucial for decidualization. We previously reported that activation of a cAMP mediator, called Exchange protein directly activated by cAMP (EPAC) promotes cAMP analog- or ovarian steroid-induced decidualization in cultured human ESCs. In addition, small interfering RNA-mediated knock-down of the EPAC subtypes, EPAC1 or EPAC2, or knock-down of Rap1, a downstream factor of EPAC signaling, blocked functional and morphological decidualization of ESCs. However, factors downstream of EPAC2 other than Rap1 have not been determined. The present study was undertaken to identify additional downstream targets of EPAC2 associated with decidualization. Using proteomic analysis, we identified calreticulin (CRT) as a potential target of EPAC2. Knock-down of CRT expression in cultured ESCs significantly inhibited PKA-selective cAMP analog- or PKA-selective cAMP analog plus EPAC-selective cAMP analog-induced PRL and IGFBP1 expression. Furthermore, CRT knock-down suppressed the ovarian steroid-stimulated PRL and IGFBP1 expression and morphological differentiation, and silencing of EPAC2 or CRT significantly increased senescence-associated β-galactosidase activity with enhanced p21 expression and decreased p53 expression. These results suggest that EPAC2 and CRT are associated with cellular senescence in ESCs. In conclusion, we demonstrate here that EPAC2-mediated CRT expression is essential for the functional and morphological differentiation of ESCs into decidual cells. Furthermore, both EPAC2 and CRT might prevent ESCs from undergoing abnormal cellular senescence during decidualization.

  12. Epac Activation Initiates Associative Odor Preference Memories in the Rat Pup (United States)

    Grimes, Matthew T.; Powell, Maria; Gutierrez, Sandra Mohammed; Darby-King, Andrea; Harley, Carolyn W.; McLean, John H.


    Here we examine the role of the exchange protein directly activated by cAMP (Epac) in ß-adrenergic-dependent associative odor preference learning in rat pups. Bulbar Epac agonist (8-pCPT-2-O-Me-cAMP, or 8-pCPT) infusions, paired with odor, initiated preference learning, which was selective for the paired odor. Interestingly, pairing odor with Epac…

  13. Long-term consumption of an obesogenic high fat diet prior to ischemia-reperfusion mediates cardioprotection via Epac1-dependent signaling. (United States)

    Edland, F; Wergeland, A; Kopperud, R; Åsrud, K S; Hoivik, E A; Witsø, S L; Æsøy, R; Madsen, L; Kristiansen, K; Bakke, M; Døskeland, S O; Jonassen, A K


    Obesity is still considered a risk factor for cardiovascular disease, although more recent knowledge also suggests obesity to be associated with reduced morbidity and mortality - the "obesity paradox". This study explores if long-term feeding of an obesogenic high fat diet renders the myocardium less susceptible to ischemic-reperfusion induced injury via Epac-dependent signaling. Wild type (wt), Epac1 (Epac1 -/- ) and Epac2 (Epac2 -/- ) deficient mice were fed a high fat (HFD) or normal chow diet (ND) for 33 ± 1 weeks. Six experimental groups were included: (1) control wt ND (wt ND ), (2) control wt HFD (wt HFD ), (3) Epac1 -/- mice on ND (Epac1 -/- ND ), (4) Epac1 -/- mice on HFD (Epac1 -/- HFD ), (5) Epac2 -/- mice on ND (Epac2 -/- ND ), and (6) Epac2 -/- mice on HFD (Epac2 -/- HFD ). Isolated ex vivo mice hearts were perfused in a constant pressure Langendorff mode, and exposed to 30min of global ischemia (GI) and 60min of reperfusion. Endpoints were infarct size and functional recovery. All groups fed a HFD presented with significantly enhanced body weight, visceral fat content and reduced glucose clearance compared to corresponding ND groups. Although the HFD cohorts presented with an overall comparable systemic capability to clear glucose, the Epac1 -/- HFD group presented with glucose levels slightly above the human diabetes criteria at the end of the intraperitoneal glucose tolerance test (ipGTT). Moreover, the HFD significantly reduced infarct size in both wild type (wt HFD 41.3 ± 5.5% vs. wt ND 58.0 ± 9.8%, p  obesogenic high fat diet in mice hearts.

  14. Elevated aggressive behavior in male mice with thyroid-specific Prkar1a and global Epac1 gene deletion. (United States)

    Russart, Kathryn L G; Huk, Danielle; Nelson, Randy J; Kirschner, Lawrence S


    Alterations in circulating thyroid hormone concentrations are associated with several psychological and behavioral disorders. In humans, behavioral disorders such as anxiety, depression, and attention-deficit hyperactivity disorder can be associated with thyroid disease. The Tpo-Cre;Prkar1aflox/flox;Epac1-/- (R1A-Epac1KO) mice, originally bred to investigate the role of exchange protein directly activated by cAMP (Epac1) in follicular thyroid cancer, displayed self-mutilating and aggressive behaviors during casual observation. To assess these atypical responses, behavioral testing was conducted with the R1A-Epac1KO mice, as well as their single knockout counterparts, the thyroid-specific Prkar1a-/- and global Epac1-/- mice. Mice of all three genotypes demonstrated increased aggressive behavior against an intruder mouse. In addition, Epac1-/- mice increased response to an auditory stimulus, and the Prkar1a-/- and R1A-Epac1KO mice increased swimming behavior in the Porsolt forced swim test. Both Prkar1a-/- mice and R1A-Epac1KO mice have increased circulating thyroxine and corticosterone concentrations. Although hyperthyroidism has not been previously associated with aggression, increased thyroid hormone signaling might contribute to the increased aggressive response to the intruder mouse, as well as the increased swimming response. Mice with a genetic background of Tpo-Cre;Prkar1aflox/flox;Epac1-/- are aggressive, and both the thyroid-specific knockout of Prkar1a and global knockout of Epac1 likely contribute to this aggressive behavior. This study supports the hypothesis that altered thyroid signaling and aggressive behavior are linked. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Contributions to the EPAC Conference

    Energy Technology Data Exchange (ETDEWEB)



    Seven contributions to the EPAC Conference are presented in this work whose titles are : review of electron guns, first operation of a femtosecond laser driven photo-injector, Priam/Antigone : a 2 D/3 D package for accelerator design, the Tesla test facility linac injector, on some RF three-dimensional simulation of magnetically coupled cells, dark current under low and high electric field, a versatile TBA lattice for a Tau-Charm factory with and without beam monochromatization. (O.L.). 78 refs., 19 figs., 9 tabs.

  16. Protein kinase A and the exchange protein directly activated by cAMP (Epac) modulate phenotype plasticity in human airway smooth muscle

    NARCIS (Netherlands)

    Roscioni, Sara S.; Prins, Alwin G.; Elzinga, Carolina R. S.; Menzen, Mark H.; Dekkers, Bart G. J.; Halayko, Andrew J.; Meurs, Herman; Maarsingh, Harm; Schmidt, Martina


    BACKGROUND AND PURPOSE Platelet-derived growth factor (PDGF) modulates the airway smooth muscle (ASM) 'contractile' phenotype to a more 'proliferative' phenotype, resulting in increased proliferation and reduced contractility. Such phenotypic modulation may contribute to airway remodelling in

  17. cAMP inhibits modulation of airway smooth muscle phenotype via the exchange protein activated by cAMP (Epac) and protein kinase A

    NARCIS (Netherlands)

    Roscioni, Sara S.; Dekkers, Bart G. J.; Prins, Alwin G.; Menzen, Mark H.; Meurs, Herman; Schmidt, Martina; Maarsingh, Harm

    BACKGROUND AND PURPOSE Changes in airway smooth muscle (ASM) phenotype may contribute to the pathogenesis of airway disease. Platelet-derived growth factor (PDGF) switches ASM from a contractile to a proliferative, hypo-contractile phenotype, a process requiring activation of extracellular

  18. Epac inhibits migration and proliferation of human prostate carcinoma cells

    NARCIS (Netherlands)

    Grandoch, M.; Rose, A.; ter Braak, M.; Jendrossek, V.; Ruebben, H.; Fischer, J. W.; Schmidt, M.; Weber, A. A.


    BACKGROUND: It was recently found that cAMP mediates protein kinase A-independent effects through Epac proteins. The aim of this study was to investigate the role of Epac in migration and proliferation of prostate carcinoma cells. METHODS: The effect of Epac activation was determined by [(3)H

  19. Glucagon stimulates hepatic FGF21 secretion through a PKA- and EPAC-dependent posttranscriptional mechanism.

    Directory of Open Access Journals (Sweden)

    Holly A Cyphert

    Full Text Available Previous studies have shown that whole body deletion of the glucagon receptor suppresses the ability of starvation to increase hepatic fibroblast growth factor 21 (FGF21 expression and plasma FGF21 concentration. Here, we investigate the mechanism by which glucagon receptor activation increases hepatic FGF21 production. Incubating primary rat hepatocyte cultures with glucagon, dibutyryl cAMP or forskolin stimulated a 3-4-fold increase in FGF21 secretion. The effect of these agents on FGF21 secretion was not associated with an increase in FGF21 mRNA abundance. Glucagon induction of FGF21 secretion was additive with the stimulatory effect of a PPARα activator (GW7647 on FGF21 secretion. Inhibition of protein kinase A (PKA and downstream components of the PKA pathway [i.e. AMP-activated protein kinase and p38 MAPK] suppressed glucagon activation of FGF21 secretion. Incubating hepatocytes with an exchange protein directly activated by cAMP (EPAC-selective cAMP analog [i.e. 8-(4-chlorophenylthio-2'-O-methyladenosine-3', 5'-cyclic monophosphate (cpTOME], stimulated a 3.9-fold increase FGF21 secretion, whereas inhibition of the EPAC effector, Rap1, suppressed glucagon activation of FGF21 secretion. Treatment of hepatocytes with insulin also increased FGF21 secretion. In contrast to glucagon, insulin activation of FGF21 secretion was associated with an increase in FGF21 mRNA abundance. Glucagon synergistically interacted with insulin to stimulate a further increase in FGF21 secretion and FGF21 mRNA abundance. These results demonstrate that glucagon increases hepatic FGF21 secretion via a posttranscriptional mechanism and provide evidence that both the PKA branch and EPAC branch of the cAMP pathway play a role in mediating this effect. These results also identify a novel synergistic interaction between glucagon and insulin in the regulation of FGF21 secretion and FGF21 mRNA abundance. We propose that this insulin/glucagon synergism plays a role in

  20. Structure-guided design of selective Epac1 and Epac2 agonists.

    Directory of Open Access Journals (Sweden)

    Frank Schwede


    Full Text Available The second messenger cAMP is known to augment glucose-induced insulin secretion. However, its downstream targets in pancreatic β-cells have not been unequivocally determined. Therefore, we designed cAMP analogues by a structure-guided approach that act as Epac2-selective agonists both in vitro and in vivo. These analogues activate Epac2 about two orders of magnitude more potently than cAMP. The high potency arises from increased affinity as well as increased maximal activation. Crystallographic studies demonstrate that this is due to unique interactions. At least one of the Epac2-specific agonists, Sp-8-BnT-cAMPS (S-220, enhances glucose-induced insulin secretion in human pancreatic cells. Selective targeting of Epac2 is thus proven possible and may be an option in diabetes treatment.

  1. PKA and Epac cooperate to augment bradykinin-induced interleukin-8 release from human airway smooth muscle cells

    Directory of Open Access Journals (Sweden)

    Halayko Andrew J


    Full Text Available Abstract Background Airway smooth muscle contributes to the pathogenesis of pulmonary diseases by secreting inflammatory mediators such as interleukin-8 (IL-8. IL-8 production is in part regulated via activation of Gq-and Gs-coupled receptors. Here we study the role of the cyclic AMP (cAMP effectors protein kinase A (PKA and exchange proteins directly activated by cAMP (Epac1 and Epac2 in the bradykinin-induced IL-8 release from a human airway smooth muscle cell line and the underlying molecular mechanisms of this response. Methods IL-8 release was assessed via ELISA under basal condition and after stimulation with bradykinin alone or in combination with fenoterol, the Epac activators 8-pCPT-2'-O-Me-cAMP and Sp-8-pCPT-2'-O-Me-cAMPS, the PKA activator 6-Bnz-cAMP and the cGMP analog 8-pCPT-2'-O-Me-cGMP. Where indicated, cells were pre-incubated with the pharmacological inhibitors Clostridium difficile toxin B-1470 (GTPases, U0126 (extracellular signal-regulated kinases ERK1/2 and Rp-8-CPT-cAMPS (PKA. The specificity of the cyclic nucleotide analogs was confirmed by measuring phosphorylation of the PKA substrate vasodilator-stimulated phosphoprotein. GTP-loading of Rap1 and Rap2 was evaluated via pull-down technique. Expression of Rap1, Rap2, Epac1 and Epac2 was assessed via western blot. Downregulation of Epac protein expression was achieved by siRNA. Unpaired or paired two-tailed Student's t test was used. Results The β2-agonist fenoterol augmented release of IL-8 by bradykinin. The PKA activator 6-Bnz-cAMP and the Epac activator 8-pCPT-2'-O-Me-cAMP significantly increased bradykinin-induced IL-8 release. The hydrolysis-resistant Epac activator Sp-8-pCPT-2'-O-Me-cAMPS mimicked the effects of 8-pCPT-2'-O-Me-cAMP, whereas the negative control 8-pCPT-2'-O-Me-cGMP did not. Fenoterol, forskolin and 6-Bnz-cAMP induced VASP phosphorylation, which was diminished by the PKA inhibitor Rp-8-CPT-cAMPS. 6-Bnz-cAMP and 8-pCPT-2'-O-Me-cAMP induced GTP

  2. Epac inhibits apoptosis of human leukocytes

    NARCIS (Netherlands)

    Grandoch, M.; Bujok, V.; Fleckenstein, D.; Schmidt, M.; Fischer, J. W.; Weber, A. -A.


    cAMP is known to participate in the regulation of apoptosis in leukocytes. Depending on the cell type, pro- and antiapoptotic effects of cAMP have been described. Thus far, most of the cAMP-dependent effects have been attributed to the activation of PKA. However, Epac proteins (direct cAMP targets

  3. Loss of phosphodiesterase 4D mediates acquired triapine resistance via Epac-Rap1-Integrin signaling. (United States)

    Miklos, Walter; Heffeter, Petra; Pirker, Christine; Hager, Sonja; Kowol, Christian R; van Schoonhoven, Sushilla; Stojanovic, Mirjana; Keppler, Bernhard K; Berger, Walter


    Triapine, an anticancer thiosemicarbazone, is currently under clinical investigation. Whereas promising results were obtained in hematological diseases, trials in solid tumors widely failed. To understand mechanisms causing triapine insensitivity, we have analysed genomic alterations in a triapine-resistant SW480 subline (SW480/tria). Only one distinct genomic loss was observed specifically in SW480/tria cells affecting the phosphodiesterase 4D (PDE4D) gene locus. Accordingly, pharmacological inhibition of PDE4D resulted in significant triapine resistance in SW480 cells. Hence, we concluded that enhanced cyclic AMP levels might confer protection against triapine. Indeed, hyperactivation of both major downstream pathways, namely the protein kinase A (PKA)-cAMP response element-binding protein (Creb) and the exchange protein activated by cAMP (Epac)-Ras-related protein 1 (Rap1) signaling axes, was observed in SW480/tria cells. Unexpectedly, inhibition of PKA did not re-sensitize SW480/tria cells against triapine. In contrast, Epac activation resulted in distinct triapine resistance in SW480 cells. Conversely, knock-down of Epac expression and pharmacological inhibition of Rap1 re-sensitized SW480/tria cells against triapine. Rap1 is a well-known regulator of integrins. Accordingly, SW480/tria cells displayed enhanced plasma membrane expression of several integrin subunits, enhanced adhesion especially to RGD-containing matrix components, and bolstered activation/expression of the integrin downstream effectors Src and RhoA/Rac. Accordingly, integrin and Src inhibition resulted in potent triapine re-sensitization especially of SW480/tria cells. In summary, we describe for the first time integrin activation based on cAMP-Epac-Rap1 signaling as acquired drug resistance mechanism. combinations of triapine with inhibitors of several steps in this resistance cascade might be feasible strategies to overcome triapine insensitivity of solid tumors.

  4. The cAMP effectors PKA and Epac activate endothelial NO synthase through PI3K/Akt pathway in human endothelial cells. (United States)

    García-Morales, Verónica; Luaces-Regueira, María; Campos-Toimil, Manuel


    3',5'-Cyclic adenosine monophosphate (cAMP) exerts an endothelium-dependent vasorelaxant action by stimulating endothelial NO synthase (eNOS) activity, and the subsequent NO release, through cAMP protein kinase (PKA) and exchange protein directly activated by cAMP (Epac) activation in endothelial cells. Here, we have investigated the mechanism by which the cAMP-Epac/PKA pathway activates eNOS. cAMP-elevating agents (forskolin and dibutyryl-cAMP) and the joint activation of PKA (6-Bnz-cAMP) and Epac (8-pCPT-2'-O-Me-cAMP) increased cytoplasmic Ca2+ concentration ([Ca2+]c) in ≤30% of fura-2-loaded isolated human umbilical vein endothelial cells (HUVEC). However, these drugs did not modify [Ca2+]c in fluo-4-loaded HUVEC monolayers. In DAF-2-loaded HUVEC monolayers, forskolin, PKA and Epac activators significantly increased NO release, and the forskolin effect was reduced by inhibition of PKA (Rp-cAMPs), Epac (ESI-09), eNOS (L-NAME) or phosphoinositide 3-kinase (PI3K; LY-294,002). On the other hand, inhibition of CaMKII (KN-93), AMPK (Compound C), or total absence of Ca2+, was without effect. In Western blot experiments, Serine 1177 phosphorylated-eNOS was significantly increased in HUVEC by cAMP-elevating agents and PKA or Epac activators. In isolated rat aortic rings LY-294,002, but not KN-93 or Compound C, significantly reduced the vasorelaxant effects of forskolin in the presence of endothelium. Our results suggest that Epac and PKA activate eNOS via Ser 1177 phosphorylation by activating the PI3K/Akt pathway, and independently of AMPK or CaMKII activation or [Ca2+]c increase. This action explains, in part, the endothelium-dependent vasorelaxant effect of cAMP. Copyright © 2017 Elsevier Inc. All rights reserved.


    National Aeronautics and Space Administration — This data set contains Ulysses Energetic Particle Composition Experiment (EPAC) 1 hour averaged omni-directional electron flux data from the Ulysses Jupiter...

  6. The Golgi apparatus is a functionally distinct Ca2+ store regulated by the PKA and Epac branches of the β1-adrenergic signaling pathway. (United States)

    Yang, Zhaokang; Kirton, Hannah M; MacDougall, David A; Boyle, John P; Deuchars, James; Frater, Brenda; Ponnambalam, Sreenivasan; Hardy, Matthew E; White, Edward; Calaghan, Sarah C; Peers, Chris; Steele, Derek S


    Ca(2+) release from the Golgi apparatus regulates key functions of the organelle, including vesicle trafficking. We found that the Golgi apparatus was the source of prolonged Ca(2+) release events that originated near the nuclei of primary cardiomyocytes. Golgi Ca(2+) release was unaffected by depletion of sarcoplasmic reticulum Ca(2+), and disruption of the Golgi apparatus abolished Golgi Ca(2+) release without affecting sarcoplasmic reticulum function, suggesting functional and spatial independence of Golgi and sarcoplasmic reticulum Ca(2+) stores. β1-Adrenoceptor stimulation triggers the production of the second messenger cAMP, which activates the Epac family of Rap guanine nucleotide exchange factors and the kinase PKA (protein kinase A). Phosphodiesterases (PDEs), including those in the PDE3 and PDE4 families, degrade cAMP. Activation of β1-adrenoceptors stimulated Golgi Ca(2+) release, an effect that required activation of Epac, PKA, and the kinase CaMKII. Inhibition of PDE3s or PDE4s potentiated β1-adrenergic-induced Golgi Ca(2+) release, which is consistent with compartmentalization of cAMP signaling near the Golgi apparatus. Interventions that stimulated Golgi Ca(2+) release appeared to increase the trafficking of vascular endothelial growth factor receptor-1 (VEGFR-1) from the Golgi apparatus to the surface membrane of cardiomyocytes. In cardiomyocytes from rats with heart failure, decreases in the abundance of PDE3s and PDE4s were associated with increased Golgi Ca(2+) release events. These data suggest that the Golgi apparatus is a focal point for β1-adrenergic-stimulated Ca(2+) signaling and that the Golgi Ca(2+) store functions independently from the sarcoplasmic reticulum and the global Ca(2+) transients that trigger contraction in cardiomyocytes. Copyright © 2015, American Association for the Advancement of Science.

  7. Modulation of angiotensin II-induced inflammatory cytokines by the Epac1-Rap1A-NHE3 pathway: implications in renal tubular pathobiology (United States)

    Xie, Ping; Joladarashi, Darukeshwara; Dudeja, Pradeep; Sun, Lin


    Besides the glomerulus, the tubulointerstitium is often concomitantly affected in certain diseases, e.g., diabetic nephropathy, and activation of the renin-angiotensin system, to a certain extent, worsens its outcome because of perturbations in hemodynamics and possibly tubuloglomerular feedback. Certain studies suggest that pathobiology of the tubulointerstitium is influenced by small GTPases, e.g., Rap1. We investigated the effect of ANG II on inflammatory cytokines, while at the same time focusing on upstream effector of Rap1, i.e., Epac1, and some of the downstream tubular transport molecules, i.e., Na/H exchanger 3 (NHE3). ANG II treatment of LLC-PK1 cells decreased Rap1a GTPase activity in a time- and dose-dependent manner. ANG II treatment led to an increased membrane translocation of NHE3, which was reduced with Epac1 and PKA activators. ANG II-induced NHE3 translocation was notably reduced with the transfection of Rap1a dominant positive mutants, i.e., Rap1a-G12V or Rap1a-T35A. Transfection of cells with dominant negative Rap1a mutants, i.e., Rap1a-S17A, or Epac1 mutant, i.e., EPAC-ΔcAMP, normalized ANG II-induced translocation of NHE3. In addition, ANG II treatment led to an increased expression of inflammatory cytokines, i.e., IL-1β, IL-6, IL-8, and TNF-α, which was reduced with Rap1a-G12V or Rap1a-T35A transfection, while it reverted to previous comparable levels following transfection of Rap1a-S17A or EPAC-ΔcAMP. ANG II-induced expression of cytokines was reduced with the treatment with NHE3 inhibitor S3226 or with Epac1 and PKA activators. These data suggest that this novel Epac1-Rap1a-NHE3 pathway conceivably modulates ANG II-induced expression of inflammatory cytokines, and this information may yield the impetus for developing strategies to reduce tubulointertstitial inflammation in various renal diseases. PMID:24553435


    National Aeronautics and Space Administration — This data set contains Ulysses Energetic Particle Composition Experiment (EPAC) 1 hour averaged sectored proton flux data from the Ulysses Jupiter encounter...

  9. Null EPAC Mutants Reveal a Sequential Order of Versatile cAMP Effects during "Drosophila" Aversive Odor Learning (United States)

    Richlitzki, Antje; Latour, Philipp; Schwärzel, Martin


    Here, we define a role of the cAMP intermediate EPAC in "Drosophila" aversive odor learning by means of null epac mutants. Complementation analysis revealed that EPAC acts downstream from the "rutabaga" adenylyl cyclase and in parallel to protein kinase A. By means of targeted knockdown and genetic rescue we identified mushroom…

  10. Allosteric activation of coagulation factor VIIa visualized by hydrogen exchange

    DEFF Research Database (Denmark)

    Rand, Kasper Dyrberg; Jørgensen, Thomas; Olsen, Ole H


    Coagulation factor VIIa (FVIIa) is a serine protease that, after binding to tissue factor (TF), plays a pivotal role in the initiation of blood coagulation. We used hydrogen exchange monitored by mass spectrometry to visualize the details of FVIIa activation by comparing the exchange kinetics...

  11. Two-photon exchange effect on deuteron electromagnetic form factors


    Dong, Yu Bing; Chen, D. Y.


    Corrections of two-photon exchange to proton and neutron electromagnetic form factors are employed to study the effect of two-photon exchange on the deuteron electromagnetic form factors. Numerical results of the effect are given. It is suggested to test the effect in the measurement of $P_z$ in a small angle limit.

  12. CB1 receptors down-regulate a cAMP/Epac2/PLC pathway to silence the nerve terminals of cerebellar granule cells. (United States)

    Alonso, Beatris; Bartolomé-Martín, David; Ferrero, José Javier; Ramírez-Franco, Jorge; Torres, Magdalena; Sánchez-Prieto, José


    Cannabinoid receptors mediate short-term retrograde inhibition of neurotransmitter release, as well as long-term depression of synaptic transmission at excitatory synapses. The responses of individual nerve terminals in VGLUT1-pHluorin transfected cerebellar granule cells to cannabinoids have shown that prolonged activation of cannabinoid type 1 receptors (CB1Rs) silences a subpopulation of previously active synaptic boutons. Adopting a combined pharmacological and genetic approach to study the molecular mechanisms of CB1R-induced silencing, we found that adenylyl cyclase inhibition decreases cAMP levels while it increases the number of silent synaptic boutons and occludes the induction of further silencing by the cannabinoid agonist HU-210. Guanine nucleotide exchange proteins directly activated by cAMP (Epac proteins) mediate some of the presynaptic effects of cAMP in the potentiation of synaptic transmission. ESI05, a selective Epac2 inhibitor, and U-73122, the specific inhibitor of phospholipase C (PLC), both augment the number of silent synaptic boutons. Moreover, they abolish the capacity of the Epac activator, 8-(4-chlorophenylthio)-2'-O-methyladenosine 3',5'-cyclic monophosphate monosodium hydrate, to prevent HU-210-induced silencing consistent with PLC signaling lying downstream of Epac2 proteins. Furthermore, Rab3-interacting molecule (RIM)1α KO cells have many more basally silent synaptic boutons (12.9 ± 3.5%) than wild-type cells (1.1 ± 0.5%). HU-210 induced further silencing in these mutant cells, although 8-(4-chlorophenylthio)-2'-O-methyladenosine 3',5'-cyclic monophosphate monosodium hydrate only awoke the HU-210-induced silence and not the basally silent synaptic boutons. This behavior can be rescued by expressing RIM1α in RIM1α KO cells, these cells behaving very much like wild-type cells. These findings support the hypothesis that a cAMP/Epac/PLC signaling pathway targeting the release machinery appears to mediate cannabinoid

  13. The microRNA-7-mediated reduction in EPAC-1 contributes to vascular endothelial permeability and eNOS uncoupling in murine experimental retinopathy

    NARCIS (Netherlands)

    Garcia-Morales, Veronica; Friedrich, Julian; Jorna, Lysanne M; Campos-Toimil, Manuel; Hammes, Hans-Peter; Schmidt, Martina; Krenning, Guido

    To investigate the consequences of oxidative stress and hypoxia on EPAC-1 expression during retinopathy. Oxygen-induced retinopathy was induced in mice and EPAC-1 expression investigated by immunofluorescence. In silico analyses were used to identify a link between EPAC-1 expression and

  14. hCG activates Epac-Erk1/2 signaling regulating Progesterone Receptor expression and function in human endometrial stromal cells. (United States)

    Tapia-Pizarro, Alejandro; Archiles, Sebastián; Argandoña, Felipe; Valencia, Cecilia; Zavaleta, Keyla; Cecilia Johnson, M; González-Ramos, Reinaldo; Devoto, Luigi


    How does hCG signal in human endometrial stromal cells (ESCs) and what is its role in regulating ESC function? hCG signaling in ESCs activates the extracellular signal-regulated protein kinases 1 and 2 (Erk1/2) pathway through exchange protein activated by cyclic AMP (cAMP) (Epac) and transiently increases progesterone receptor (PR) transcript and protein expression and its transcriptional function. hCG is one of the earliest embryo-derived secreted signals in the endometrium, which abundantly expresses LH/hCG receptors. hCG signals through cAMP/protein kinase A (PKA) in gonadal cells, but in endometrial epithelial cells, hCG induces Erk1/2 activation independent of the cAMP/PKA pathway. Few data exist concerning the signal transduction pathways triggered by hCG in ESCs and their role in regulation of ESC function. This is an in vitro study comprising patients undergoing benign gynecological surgery (n = 46). Endometrial samples were collected from normal cycling women during the mid-secretory phase for ESCs isolation. The study conducted in an academic research laboratory within a tertiary-care hospital. The activation of the Erk1/2 signal transduction pathway elicited by hCG was evaluated in ESC. Signaling pathway inhibitors were used to examine the roles of PKA, PI3K, PKC, adenylyl cyclase and Epac on the hCG-stimulated up-regulation of phospho-Erk1/2 (pErk1/2). Erk1/2 phosphorylation was determined by immunoblot. siRNA targeting Epac was used to investigate the molecular mechanisms. To assess the role of Erk1/2 signaling induced by hCG on ESC function, gene expression regulation was examined by immunofluorescence and real-time quantitative PCR. The role of PR on the regulation of transcript levels was studied using progesterone and the PR antagonist RU486. All experiments were conducted using at least three different cell culture preparations in triplicate. Addition of hCG to ESCs in vitro induced the phosphorylation of Erk1/2 through cAMP accumulation. Such

  15. Epac1 and PDZ-GEF cooperate in Rap1 mediated endothelial junction control

    NARCIS (Netherlands)

    Pannekoek, W.J.; van Dijk, J.; Chan, O.Y.; Huveneers, S.; Linnemann, J.R.; Spanjaard, E.; Brouwer, P.E.M.; van der Meer, A.J.; Zwartkruis, F.J.; Rehmann, H.; de Rooij, J.; Bos, J.


    Epac1 and its effector Rap1 are important mediators of cAMP induced tightening of endothelial junctions and consequential increased barrier function. We have investigated the involvement of Rap1 signalling in basal, unstimulated, barrier function of a confluent monolayer of HUVEC using real time

  16. A GTP-exchange factor required for cell orientation. (United States)

    Nern, A; Arkowitz, R A


    The Rho-family of GTPases and their regulators are essential for cytoskeletal reorganization and transcriptional activation in response to extracellular signals. Little is known about what links these molecules to membrane receptors. In the budding yeast Saccharomyces cerevisiae, haploid cells respond to mating pheromone through a G-protein-coupled receptor and the betagamma subunit of the G protein, resulting in arrest of the cell cycle, transcriptional activation, and polarized growth towards a mating partner. The Rho-family GTPase Cdc42 and its exchange factor Cdc24 have been implicated in the mating process, but their specific role is unknown. Here we report the identification of cdc24 alleles that do not affect vegetative growth but drastically reduce the ability of yeast cells to mate. When exposed to mating pheromone, these mutants arrest growth, activate transcription, and undergo characteristic morphological and actin-cytoskeleton polarization. However, the mutants are unable to orient towards a pheromone gradient, and instead position their mating projection adjacent to their previous bud site. The mutants are specifically defective in the binding of Cdc24 to the G-protein betagamma subunit. Our results demonstrate that the association of an exchange factor and the betagamma subunit of a hetero-trimeric G protein links receptor-mediated activation to oriented cell growth.

  17. Factors contributing to attitude exchange amongst preservice elementary teachers (United States)

    Palmer, David H.


    Previous research has shown that elementary education majors often dislike science and lack confidence in their ability to teach it. This is an important problem because students who hold these attitudes are likely to avoid teaching science, or teach it poorly, when they become teachers. It is therefore necessary to identify preservice elementary teachers who hold negative attitudes towards science, and attempt to convert these attitudes to positive before they become teachers. This study was designed to identify students whose attitudes had changed from negative to positive (i.e., attitude exchange had occurred) after participating in a one-semester elementary science education course, and to identify the course factors that were responsible. Four participants were individually interviewed. The transcripts indicated that attitude exchange had occurred for each of the four students. Each student described several features of the course that had a positive influence. These were of three main types: personal attributes of the tutor, specific teaching strategies, and external validation. It was proposed that many of the individual factors were effective because they represented either performance accomplishments or vicarious experience as defined by Bandura (Psychological Review, 84, 1977, 191-215).

  18. Activation of G protein-coupled estrogen receptor 1 induces coronary artery relaxation via Epac/Rap1-mediated inhibition of RhoA/Rho kinase pathway in parallel with PKA.

    Directory of Open Access Journals (Sweden)

    Xuan Yu

    Full Text Available Previously, we reported that cAMP/PKA signaling is involved in GPER-mediated coronary relaxation by activating MLCP via inhibition of RhoA pathway. In the current study, we tested the hypothesis that activation of GPER induces coronary artery relaxation via inhibition of RhoA/Rho kinase pathway by cAMP downstream targets, exchange proteins directly activated by cAMP (Epac as well as PKA. Our results show that Epac inhibitors, brefeldin A (BFA, 50 μM, or ESI-09 (20 μM, or CE3F4 (100 μM, all partially inhibited porcine coronary artery relaxation response to the selective GPER agonist, G-1 (0.3-3 μM; while concurrent administration of BFA and PKI (5 μM, a PKA inhibitor, almost completely blocked the relaxation effect of G-1. The Epac specific agonist, 8-CPT-2Me-cAMP (007, 1-100 μM, induced a concentration-dependent relaxation response. Furthermore, the activity of Ras-related protein 1 (Rap1 was up regulated by G-1 (1 μM treatment of porcine coronary artery smooth muscle cells (CASMCs. Phosphorylation of vasodilator-stimulated phosphoprotein (p-VASP was elevated by G-1 (1 μM treatment, but not by 007 (50 μM; and the effect of G-1 on p-VASP was blocked by PKI, but not by ESI-09, an Epac antagonist. RhoA activity was similarly down regulated by G-1 and 007, whereas ESI-09 restored most of the reduced RhoA activity by G-1 treatment. Furthermore, G-1 decreased PGF2α-induced p-MYPT1, which was partially reversed with either ESI-09 or PKI; whereas, concurrent administration of ESI-09 and PKI totally prevented the inhibitory effect of G-1. The inhibitory effects of G-1 on p- MLC levels in CASMCs were mostly restored by either ESI-09 or PKI. These results demonstrate that activation of GPER induces coronary artery relaxation via concurrent inhibition of RhoA/Rho kinase by Epac/Rap1 and PKA. GPER could be a potential drug target for preventing and treating cardiovascular diseases.

  19. cAMP and EPAC are key players in the regulation of the signal transduction pathway involved in the α-hemolysin autophagic response.

    Directory of Open Access Journals (Sweden)

    María Belén Mestre

    Full Text Available Staphylococcus aureus is a microorganism that causes serious diseases in the human being. This microorganism is able to escape the phagolysosomal pathway, increasing intracellular bacterial survival and killing the eukaryotic host cell to spread the infection. One of the key features of S. aureus infection is the production of a series of virulence factors, including secreted enzymes and toxins. We have shown that the pore-forming toxin α-hemolysin (Hla is the S. aureus-secreted factor responsible for the activation of the autophagic pathway and that this response occurs through a PI3K/Beclin1-independent form. In the present report we demonstrate that cAMP has a key role in the regulation of this autophagic response. Our results indicate that cAMP is able to inhibit the autophagy induced by Hla and that PKA, the classical cAMP effector, does not participate in this regulation. We present evidence that EPAC and Rap2b, through calpain activation, are the proteins involved in the regulation of Hla-induced autophagy. Similar results were obtained in cells infected with different S. aureus strains. Interestingly, in this report we show, for the first time to our knowledge, that both EPAC and Rap2b are recruited to the S. aureus-containing phagosome. We believe that our findings have important implications in understanding innate immune processes involved in intracellular pathogen invasion of the host cell.

  20. cAMP and EPAC Are Key Players in the Regulation of the Signal Transduction Pathway Involved in the α-Hemolysin Autophagic Response (United States)

    Mestre, María Belén; Colombo, María Isabel


    Staphylococcus aureus is a microorganism that causes serious diseases in the human being. This microorganism is able to escape the phagolysosomal pathway, increasing intracellular bacterial survival and killing the eukaryotic host cell to spread the infection. One of the key features of S. aureus infection is the production of a series of virulence factors, including secreted enzymes and toxins. We have shown that the pore-forming toxin α-hemolysin (Hla) is the S. aureus–secreted factor responsible for the activation of the autophagic pathway and that this response occurs through a PI3K/Beclin1-independent form. In the present report we demonstrate that cAMP has a key role in the regulation of this autophagic response. Our results indicate that cAMP is able to inhibit the autophagy induced by Hla and that PKA, the classical cAMP effector, does not participate in this regulation. We present evidence that EPAC and Rap2b, through calpain activation, are the proteins involved in the regulation of Hla-induced autophagy. Similar results were obtained in cells infected with different S. aureus strains. Interestingly, in this report we show, for the first time to our knowledge, that both EPAC and Rap2b are recruited to the S. aureus–containing phagosome. We believe that our findings have important implications in understanding innate immune processes involved in intracellular pathogen invasion of the host cell. PMID:22654658

  1. Vav family exchange factors: an integrated regulatory and functional view. (United States)

    Bustelo, Xosé R


    The Vav family is a group of tyrosine phosphorylation-regulated signal transduction molecules hierarchically located downstream of protein tyrosine kinases. The main function of these proteins is to work as guanosine nucleotide exchange factors (GEFs) for members of the Rho GTPase family. In addition, they can exhibit a variety of catalysis-independent roles in specific signaling contexts. Vav proteins play essential signaling roles for both the development and/or effector functions of a large variety of cell lineages, including those belonging to the immune, nervous, and cardiovascular systems. They also contribute to pathological states such as cancer, immune-related dysfunctions, and atherosclerosis. Here, I will provide an integrated view about the evolution, regulation, and effector properties of these signaling molecules. In addition, I will discuss the pros and cons for their potential consideration as therapeutic targets.

  2. Dock-family exchange factors in cell migration and disease. (United States)

    Gadea, Gilles; Blangy, Anne


    Dock family proteins are evolutionary conserved exchange factors for the Rho GTPases Rac and Cdc42. There are 11 Dock proteins in mammals, named Dock1 (or Dock180) to Dock11 that play different cellular functions. In particular, Dock proteins regulate actin cytoskeleton, cell adhesion and migration. Not surprisingly, members of the Dock family have been involved in various pathologies, including cancer and defects in the central nervous and immune systems. This review proposes an update of the recent findings regarding the function of Dock proteins, focusing on their role in the control of cell migration and invasion and the consequences in human diseases. Copyright © 2014 Elsevier GmbH. All rights reserved.

  3. Chlamydial entry involves TARP binding of guanine nucleotide exchange factors.

    Directory of Open Access Journals (Sweden)

    B Josh Lane


    Full Text Available Chlamydia trachomatis attachment to cells induces the secretion of the elementary body-associated protein TARP (Translocated Actin Recruiting Protein. TARP crosses the plasma membrane where it is immediately phosphorylated at tyrosine residues by unknown host kinases. The Rac GTPase is also activated, resulting in WAVE2 and Arp2/3-dependent recruitment of actin to the sites of chlamydia attachment. We show that TARP participates directly in chlamydial invasion activating the Rac-dependent signaling cascade to recruit actin. TARP functions by binding two distinct Rac guanine nucleotide exchange factors (GEFs, Sos1 and Vav2, in a phosphotyrosine-dependent manner. The tyrosine phosphorylation profile of the sequence YEPISTENIYESI within TARP, as well as the transient activation of the phosphatidylinositol 3-kinase (PI3-K, appears to determine which GEF is utilized to activate Rac. The first and second tyrosine residues, when phosphorylated, are utilized by the Sos1/Abi1/Eps8 and Vav2, respectively, with the latter requiring the lipid phosphatidylinositol 3,4,5-triphosphate. Depletion of these critical signaling molecules by siRNA resulted in inhibition of chlamydial invasion to varying degrees, owing to a possible functional redundancy of the two pathways. Collectively, these data implicate TARP in signaling to the actin cytoskeleton remodeling machinery, demonstrating a mechanism by which C.trachomatis invades non-phagocytic cells.

  4. Mutations in elongation factor 1beta, a guanine nucleotide exchange factor, enhance translational fidelity. (United States)

    Carr-Schmid, A; Valente, L; Loik, V I; Williams, T; Starita, L M; Kinzy, T G


    Translation elongation factor 1beta (EF-1beta) is a member of the family of guanine nucleotide exchange factors, proteins whose activities are important for the regulation of G proteins critical to many cellular processes. EF-1beta is a highly conserved protein that catalyzes the exchange of bound GDP for GTP on EF-1alpha, a required step to ensure continued protein synthesis. In this work, we demonstrate that the highly conserved C-terminal region of Saccharomyces cerevisiae EF-1beta is sufficient for normal cell growth. This region of yeast and metazoan EF-1beta and the metazoan EF-1beta-like protein EF-1delta is highly conserved. Human EF-1beta, but not human EF-1delta, is functional in place of yeast EF-1beta, even though both EF-1beta and EF-1delta have previously been shown to have guanine nucleotide exchange activity in vitro. Based on the sequence and functional homology, mutagenesis of two C-terminal residues identical in all EF-1beta protein sequences was performed, resulting in mutants with growth defects and sensitivity to translation inhibitors. These mutants also enhance translational fidelity at nonsense codons, which correlates with a reduction in total protein synthesis. These results indicate the critical function of EF-1beta in regulating EF-1alpha activity, cell growth, translation rates, and translational fidelity.

  5. Mutations in Elongation Factor 1β, a Guanine Nucleotide Exchange Factor, Enhance Translational Fidelity (United States)

    Carr-Schmid, Anne; Valente, Louis; Loik, Valerie I.; Williams, Tanishia; Starita, Lea M.; Kinzy, Terri Goss


    Translation elongation factor 1β (EF-1β) is a member of the family of guanine nucleotide exchange factors, proteins whose activities are important for the regulation of G proteins critical to many cellular processes. EF-1β is a highly conserved protein that catalyzes the exchange of bound GDP for GTP on EF-1α, a required step to ensure continued protein synthesis. In this work, we demonstrate that the highly conserved C-terminal region of Saccharomyces cerevisiae EF-1β is sufficient for normal cell growth. This region of yeast and metazoan EF-1β and the metazoan EF-1β-like protein EF-1δ is highly conserved. Human EF-1β, but not human EF-1δ, is functional in place of yeast EF-1β, even though both EF-1β and EF-1δ have previously been shown to have guanine nucleotide exchange activity in vitro. Based on the sequence and functional homology, mutagenesis of two C-terminal residues identical in all EF-1β protein sequences was performed, resulting in mutants with growth defects and sensitivity to translation inhibitors. These mutants also enhance translational fidelity at nonsense codons, which correlates with a reduction in total protein synthesis. These results indicate the critical function of EF-1β in regulating EF-1α activity, cell growth, translation rates, and translational fidelity. PMID:10409717

  6. Common factors and the exchange rate: results from the Brazilian case

    Directory of Open Access Journals (Sweden)

    Wilson Rafael de Oliveira Felício


    Full Text Available This paper studies the usefulness of factor models in explaining the dynamics of the exchange rate Real / Dollar from January 1999 to August 2011. The paper verifies that the inclusion of factors embedded on the common movements of exchange rates of a set of countries significantly improves the in-sample and out-of-sample predictive power of the models comprising only macroeconomic fundamentals commonly used in the literature to forecast the exchange rate. The paper also links the information contained in the factors to global shocks like the demand for dollars - a "dollar effect", volatility and liquidity of global financial markets.

  7. Analysis of factors affecting gas exchange in intravascular blood gas exchanger. (United States)

    Niranjan, S C; Clark, J W; San, K Y; Zwischenberger, J B; Bidani, A


    A mathematical model of an intravascular hollow-fiber gas-exchange device, called IVOX, has been developed using a Krogh cylinder-like approach with a repeating unit structure comprised of a single fiber with gas flowing through its lumen surrounded by a coaxial cylinder of blood flowing in the opposite direction. Species mass balances on O2 and CO2 result in a nonlinear coupled set of convective-diffusion parabolic partial differential equations that are solved numerically using an alternating-direction implicit finite-difference method. Computed results indicated the presence of a large resistance to gas transport on the external (blood) side of the hollow-fiber exchanger. Increasing gas flow through the device favored CO2 removal from but not O2 addition to blood. Increasing blood flow over the device favored both CO2 removal as well as O2 addition. The rate of CO2 removal increased linearly with the transmural PCO2 gradient imposed across the device. The effect of fiber crimping on blood phase mass transfer resistance was evaluated indirectly by varying species blood diffusivity. Computed results indicated that CO2 excretion by IVOX can be significantly enhanced with improved bulk mixing of vena caval blood around the IVOX fibers.

  8. Influence of market factors on the pricing of exchange traded metals in the medium term (United States)

    Bogdanov, S. V.; Shevelev, I. M.; Chernyi, S. A.


    On the basis of comparison of the influence of the stock exchange factors on the pricing of nonferrous metals for medium term with similar results for short term, it has been established that the main attention should be paid to the changes in the pricing environment on the metal market as a function of the prices of exchange traded metals. The situation on the market of energy carriers (hydrocarbons) and the European, American, and Asian stock exchanges can be based on parity and even significantly influence the variation of the metal prices. In the medium term, constructive development of metal trade should be reasonably promoted by changing the elasticity of supply with regard to prices for exchange traded metals and by applying the stock exchange factors that positively influence the pricing on commodity and stock markets.

  9. Risk factors for transient dysfunction of gas exchange after cardiac surgery

    Directory of Open Access Journals (Sweden)

    Cristiane Delgado Alves Rodrigues


    Full Text Available Objective: A retrospective cohort study was preformed aiming to verify the presence of transient dysfunction of gas exchange in the postoperative period of cardiac surgery and determine if this disorder is linked to cardiorespiratory events. Methods: We included 942 consecutive patients undergoing cardiac surgery and cardiac procedures who were referred to the Intensive Care Unit between June 2007 and November 2011. Results: Fifteen patients had acute respiratory distress syndrome (2%, 199 (27.75% had mild transient dysfunction of gas exchange, 402 (56.1% had moderate transient dysfunction of gas exchange, and 39 (5.4% had severe transient dysfunction of gas exchange. Hypertension and cardiogenic shock were associated with the emergence of moderate transient dysfunction of gas exchange postoperatively (P=0.02 and P=0.019, respectively and were risk factors for this dysfunction (P=0.0023 and P=0.0017, respectively. Diabetes mellitus was also a risk factor for transient dysfunction of gas exchange (P=0.03. Pneumonia was present in 8.9% of cases and correlated with the presence of moderate transient dysfunction of gas exchange (P=0.001. Severe transient dysfunction of gas exchange was associated with patients who had renal replacement therapy (P=0.0005, hemotherapy (P=0.0001, enteral nutrition (P=0.0012, or cardiac arrhythmia (P=0.0451. Conclusion: Preoperative hypertension and cardiogenic shock were associated with the occurrence of postoperative transient dysfunction of gas exchange. The preoperative risk factors included hypertension, cardiogenic shock, and diabetes. Postoperatively, pneumonia, ventilator-associated pneumonia, renal replacement therapy, hemotherapy, and cardiac arrhythmia were associated with the appearance of some degree of transient dysfunction of gas exchange, which was a risk factor for reintubation, pneumonia, ventilator-associated pneumonia, and renal replacement therapy in the postoperative period of cardiac surgery and

  10. Exchange rate prediction with multilayer perceptron neural network using gold price as external factor

    Directory of Open Access Journals (Sweden)

    Mohammad Fathian


    Full Text Available In this paper, the problem of predicting the exchange rate time series in the foreign exchange rate market is going to be solved using a time-delayed multilayer perceptron neural network with gold price as external factor. The input for the learning phase of the artificial neural network are the exchange rate data of the last five days plus the gold price in two different currencies of the exchange rate as the external factor for helping the artificial neural network improving its forecast accuracy. The five-day delay has been chosen because of the weekly cyclic behavior of the exchange rate time series with the consideration of two holidays in a week. The result of forecasts are then compared with using the multilayer peceptron neural network without gold price external factor by two most important evaluation techniques in the literature of exchange rate prediction. For the experimental analysis phase, the data of three important exchange rates of EUR/USD, GBP/USD, and USD/JPY are used.

  11. Advanced view factor analysis method for radiation exchange. (United States)

    Park, Sookuk; Tuller, Stanton E


    A raster-based method for determining complex view factor patterns is presented (HURES model). The model uses Johnson and Watson's view factor analysis method for fisheye lens photographs. The entire sphere is divided into 13 different view factors: open sky; sunny and shaded building walls, vegetation (trees) and ground surfaces above and below 1.2 m from the ground surface. The HURES model gave reasonable view factor results in tests at two urban study sites on summer days: downtown Nanaimo, B.C., Canada and Changwon, Republic of Korea. HURES gave better estimates of open sky view factors determined from fisheye lens photographs than did ENVI-met 3.1 and RayMan Pro. However, all three models underestimated sky view factor. For view factor analysis in outdoor urban areas, the 10° interval of rotation angle at 100 m distance of annuli will be suitable settings for three-dimensional computer simulations. The HURES model can be used for the rapid determination of complex view factor patterns which facilitates the analysis of their effects. Examples of how differing view factor patterns can affect human thermal sensation indices are given. The greater proportion of sunny view factors increased the computed predicted mean vote (PMV) by 1.3 on the sunny side of the street compared with the shady side during mid-morning in downtown Nanaimo. In another example, effects of differing amounts of open sky, sunny ground, sunny buildings and vegetation combined to produce only slight differences in PMV and two other human thermal sensation indices, PET and UTCI.

  12. Factors Influencing the Thermal Efficiency of Horizontal Ground Heat Exchangers

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    Eloisa Di Sipio


    Full Text Available The performance of very shallow geothermal systems (VSGs, interesting the first 2 m of depth from ground level, is strongly correlated to the kind of sediment locally available. These systems are attractive due to their low installation costs, less legal constraints, easy maintenance and possibility for technical improvements. The Improving Thermal Efficiency of horizontal ground heat exchangers Project (ITER aims to understand how to enhance the heat transfer of the sediments surrounding the pipes and to depict the VSGs behavior in extreme thermal situations. In this regard, five helices were installed horizontally surrounded by five different backfilling materials under the same climatic conditions and tested under different operation modes. The field test monitoring concerned: (a monthly measurement of thermal conductivity and moisture content on surface; (b continuous recording of air and ground temperature (inside and outside each helix; (c continuous climatological and ground volumetric water content (VWC data acquisition. The interactions between soils, VSGs, environment and climate are presented here, focusing on the differences and similarities between the behavior of the helix and surrounding material, especially when the heat pump is running in heating mode for a very long time, forcing the ground temperature to drop below 0 °C.

  13. Stochastic Discount Factor Approach to International Risk-Sharing: Evidence from Fixed Exchange Rate Episodes


    Hadzi-Vaskov, M.; C.J.M. Kool


    This paper presents evidence of the stochastic discount factor approach to international risk-sharing applied to fixed exchange rate regimes. We calculate risk-sharing indices for two episodes of fixed or very rigid exchange rates: the Eurozone before and after the introduction of the Euro, and several emerging economies in the period 1993-2005. This approach suggests almost perfect bilateral risk-sharing among all countries from the Eurozone. Moreover, it implies that emerging markets with f...

  14. The Emerging Role of Guanine Exchange Factors in ALS and other neurodegenerative diseases

    Directory of Open Access Journals (Sweden)

    Cristian eDroppelmann


    Full Text Available Small GTPases participate in a broad range of cellular processes such as proliferation, differentiation and migration. The exchange of GDP for GTP resulting in the activation of these GTPases is catalyzed by a group of enzymes called guanine nucleotide exchange factors (GEFs, of which two classes: Dbl-related exchange factors and the more recently described Dock family exchange factors. Increasingly, deregulation of normal GEF activity or function has been associated with a broad range of disease states, including neurodegeneration and neurodevelopmental disorders. In this review, we examine this evidence with special emphasis on the novel role of Rho guanine nucleotide exchange factor (RGNEF/p190RhoGEF in the pathogenesis of amyotrophic lateral sclerosis (ALS. RGNEF is the first neurodegeneration-linked GEF that regulates not only RhoA GTPase activation but also functions as an RNA binding protein that directly acts with low molecular weight neurofilament (NEFL mRNA 3’UTR to regulate its stability. This dual role for RGNEF, coupled with the increasing understanding of the key role for GEFs in modulating the GTPase function in cell survival suggests a prominent role for GEFs in mediating a critical balance between cytotoxicity and neuroprotection which, when disturbed, contributes to neuronal loss.

  15. Structural outline of the detailed mechanism for elongation factor Ts-mediated guanine nucleotide exchange on elongation factor Tu. (United States)

    Thirup, Søren S; Van, Lan Bich; Nielsen, Tine K; Knudsen, Charlotte R


    Translation elongation factor EF-Tu belongs to the superfamily of guanine-nucleotide binding proteins, which play key cellular roles as regulatory switches. All G-proteins require activation via exchange of GDP for GTP to carry out their respective tasks. Often, guanine-nucleotide exchange factors are essential to this process. During translation, EF-Tu:GTP transports aminoacylated tRNA to the ribosome. GTP is hydrolyzed during this process, and subsequent reactivation of EF-Tu is catalyzed by EF-Ts. The reaction path of guanine-nucleotide exchange is structurally poorly defined for EF-Tu and EF-Ts. We have determined the crystal structures of the following reaction intermediates: two structures of EF-Tu:GDP:EF-Ts (2.2 and 1.8Å resolution), EF-Tu:PO4:EF-Ts (1.9Å resolution), EF-Tu:GDPNP:EF-Ts (2.2Å resolution) and EF-Tu:GDPNP:pulvomycin:Mg(2+):EF-Ts (3.5Å resolution). These structures provide snapshots throughout the entire exchange reaction and suggest a mechanism for the release of EF-Tu in its GTP conformation. An inferred sequence of events during the exchange reaction is presented. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  16. Multinational telecommunications operators : impact of market factors and foreign currency exchange rate variations in their stock returns


    Oliveira, Maria da Conceição T. F. Monteiro H.


    Mestrado em Finanças Firms are exposed to foreign exchange risk when the results of their projects depend on future exchange rates and those exchange rates can not be fully anticipated. Through the last 50 years, exchange risk management has received increasing attention in both corporate practice and literature. Firms are also exposed to other market factors, domestic and internationally, with a major impact on their stock returns. During the past decade the telecommunications sector has ...

  17. On factors influencing air-water gas exchange in emergent wetlands (United States)

    Ho, David T.; Engel, Victor C.; Ferron, Sara; Hickman, Benjamin; Choi, Jay; Harvey, Judson W.


    Knowledge of gas exchange in wetlands is important in order to determine fluxes of climatically and biogeochemically important trace gases and to conduct mass balances for metabolism studies. Very few studies have been conducted to quantify gas transfer velocities in wetlands, and many wind speed/gas exchange parameterizations used in oceanographic or limnological settings are inappropriate under conditions found in wetlands. Here six measurements of gas transfer velocities are made with SF6 tracer release experiments in three different years in the Everglades, a subtropical peatland with surface water flowing through emergent vegetation. The experiments were conducted under different flow conditions and with different amounts of emergent vegetation to determine the influence of wind, rain, water flow, waterside thermal convection, and vegetation on air-water gas exchange in wetlands. Measured gas transfer velocities under the different conditions ranged from 1.1 cm h−1 during baseline conditions to 3.2 cm h−1 when rain and water flow rates were high. Commonly used wind speed/gas exchange relationships would overestimate the gas transfer velocity by a factor of 1.2 to 6.8. Gas exchange due to thermal convection was relatively constant and accounted for 14 to 51% of the total measured gas exchange. Differences in rain and water flow among the different years were responsible for the variability in gas exchange, with flow accounting for 37 to 77% of the gas exchange, and rain responsible for up to 40%.

  18. Coming to Canada to Study: Factors that Influence Student's Decisions to Participate in International Exchange (United States)

    Massey, Jennifer; Burrow, Jeff


    Increasing numbers of students are participating in study abroad programs. Outcomes associated with these programs have been studied extensively, but relatively little is known about what motivates and influences students to participate. This study investigated factors that motivate and influence students to study on exchange and explored how…

  19. Membrane association of the Arabidopsis ARF exchange factor GNOM involves interaction of conserved domains

    DEFF Research Database (Denmark)

    Anders, Nadine; Nielsen, Michael M.; Keicher, Jutta


    The GNOM protein plays a fundamental role in Arabidopsis thaliana development by regulating endosome-to-plasma membrane trafficking required for polar localization of the auxin efflux carrier PIN1. GNOM is a family member of large ARF guanine nucleotide exchange factors (ARF-GEFs), which regulate...

  20. Leader-Member Exchange (LMX) and Psychosocial Factors at Work Among Healthcare Professionals

    DEFF Research Database (Denmark)

    Johansson Hanse, Jan; Harlin, Ulrika; Jarebrant, Caroline


    Aim: The study aims to examine the associations between leader–member exchange (LMX) and psychosocial factors at work. Methods: A questionnaire-based cross-sectional study was undertaken at four units in two not-for-profit hospitals in southwestern Sweden. The study sample included 240 employees...

  1. Factors influencing intentions to use social recommender systems: a social exchange perspective. (United States)

    Chang, Tsung-Sheng; Hsiao, Wei-Hung


    This study employs the perspective of social exchange theory and seeks to understand users' intentions to use social recommender systems (SRS) through three psychological factors: trust, shared values, and reputation. We use structural equation modeling to analyze 221 valid questionnaires. The results show that trust has a direct positive influence on the intention to use SRS, followed by shared values, whereas reputation has an indirect influence on SRS use. We further discuss specific recommendations concerning these factors for developing SRS.

  2. Severe Neonatal Hyperbilirubinemia; Causes and Contributing Factors Leading to Exchange Transfusion at Ghaem Hospital in Mashhad

    Directory of Open Access Journals (Sweden)

    Farhad Heydarian


    Full Text Available Hyperbilirubinemia is common in neonates; it can have a serious rising course. Due to its critical morbidity called "kernicterus", severe neonatal hyperbilirubinemia causes which lead to exchange transfusion, should be clarified. This descriptive cross sectional study performed with reviewing of files of 118 neonates weighting 2kg and more who had exchange transfusion in pediatrics ward at Ghaem training hospital in Mashhad from April 2004 to March 2007. Among 118 patients, 75 (63.6% were male, and 43 patients (36.4% were female. The most common cause of exchange transfusion was ABO incompatibility (38.1%. In order of frequency, unknown etiology (25.4%, Rh incompatibility (16.1% with no immune hydrops, Sepsis(8.5%, urinary tract infection (5.1% and others (3.4% (Including Crigler-Najjar and cephalohematoma were next ones. Vaginal delivery and exclusive breast feeding were detected as associated factors. Mean serum bilirubin levels was 28.7 mg/dl (SD. 9.2 ABO incompatibility. ABO incompatibility was the main cause of exchange transfusion. Male gender, vaginal delivery and exclusive breast feeding were seen more among patients who need to be exchanged. So in case of ABO incompatibility especially when delivery route is vaginal, newborns should be visited soon again after early discharge from hospital.

  3. Severe Neonatal Hyperbilirubinemia; Causes and Contributing Factors Leading to Exchange Transfusion at Ghaem Hospital in Mashhad

    Directory of Open Access Journals (Sweden)

    Farhad Heydarian


    Full Text Available "nHyperbilirubinemia is common in neonates; it can have a serious rising course. Due to its critical morbidity called "kernicterus", severe neonatal hyperbilirubinemia causes which lead to exchange transfusion, should be clarified. This descriptive cross sectional study performed with reviewing of files of 118 neonates weighting 2kg and more who had exchange transfusion in pediatrics ward at Ghaem training hospital in Mashhad from April 2004 to March 2007. Among 118 patients, 75 (63.6% were male, and 43 patients (36.4% were female. The most common cause of exchange transfusion was ABO incompatibility (38.1%. In order of frequency, unknown etiology (25.4%, Rh incompatibility (16.1% with no immune hydrops, Sepsis(8.5%, urinary tract infection (5.1% and others (3.4% (Including Crigler-Najjar and cephalohematoma were next ones. Vaginal delivery and exclusive breast feeding were detected as associated factors. Mean serum bilirubin levels was 28.7 mg/dl (SD. 9.2 ABO incompatibility. ABO incompatibility was the main cause of exchange transfusion. Male gender, vaginal delivery and exclusive breast feeding were seen more among patients who need to be exchanged. So in case of ABO incompatibility especially when delivery route is vaginal, newborns should be visited soon again after early discharge from hospital.

  4. A comparison of donor-acceptor pairs for genetically encoded FRET sensors: application to the Epac cAMP sensor as an example.

    Directory of Open Access Journals (Sweden)

    Gerard N M van der Krogt

    Full Text Available We recently reported on CFP-Epac-YFP, an Epac-based single polypeptide FRET reporter to resolve cAMP levels in living cells. In this study, we compared and optimized the fluorescent protein donor/acceptor pairs for use in biosensors such as CFP-Epac-YFP. Our strategy was to prepare a wide range of constructs consisting of different donor and acceptor fluorescent proteins separated by a short linker. Constructs were expressed in HEK293 cells and tested for FRET and other relevant properties. The most promising pairs were subsequently used in an attempt to improve the FRET span of the Epac-based cAMP sensor. The results show significant albeit not perfect correlation between performance in the spacer construct and in the Epac sensor. Finally, this strategy enabled us to identify improved sensors both for detection by sensitized emission and by fluorescent lifetime imaging. The present overview should be helpful in guiding development of future FRET sensors.

  5. Factors affecting direct and indirect benefit exchange in the social media–based learning experience

    Directory of Open Access Journals (Sweden)

    Peter L. Mkhize


    Full Text Available Background: Social media platforms are thriving on the co-creation of content, usually socially orientated content about the social interests of participants. There is also a growing trend of social media application in the human resources and marketing for business purposes. This study investigates factors that have an impact on the sharing of knowledge on social media platforms, particularly students at an Open Distance Learning (ODL institution.Objective: This study evaluates the difference between direct and indirect benefit exchange expected by students when sharing knowledge.Method: Random and theoretical sampling were used to select the sample in this study from the population. A literature-informed questionnaire was used as an instrument to collect data from a selected sample of 315 students from the School of Computing at the University of South Africa.Results: A test of association was conducted to evaluate correlations, which revealed that only reputation and social language correlate with direct and indirect benefit exchange. Results indicate that there is a significant mean difference between direct and indirect benefit exchange and that issues concerning social identity and trust should be taken into account when developing social media instructional design.Conclusion: In this study, a survey was used to test the hypothesis. The authors concluded that instructional designer can design teaching and learning experience in the social media platform by catering for both direct and indirect benefit knowledge exchange. The results of the study further confirmed that some students share knowledge with the expectation of direct exchange benefit and, meanwhile, expect indirect exchange benefit.

  6. The exchange factor Cdc24 is required for cell fusion during yeast mating. (United States)

    Barale, Sophie; McCusker, Derek; Arkowitz, Robert A


    During Saccharomyces cerevisiae mating, chemotropic growth and cell fusion are critical for zygote formation. Cdc24p, the guanine nucleotide exchange factor for the Cdc42 G protein, is necessary for oriented growth along a pheromone gradient during mating. To understand the functions of this critical Cdc42p activator, we identified additional cdc24 mating mutants. Two mating-specific mutants, the cdc24-m5 and cdc24-m6 mutants, each were isolated with a mutated residue in the conserved catalytic domain. The cdc24-m6 mutant responds normally to pheromone and orients its growth towards a mating partner yet accumulates prezygotes during mating. cdc24-m6 prezygotes have two apposed intact cell walls and do not correctly localize proteins required for cell fusion, despite normal exocytosis. Our results indicate that the exchange factor Cdc24p is necessary for maintaining or restricting specific proteins required for cell fusion to the cell contact region during mating.

  7. Contact Activation of Blood Plasma and Factor XII by Ion-exchange Resins


    Yeh, Chyi-Huey Josh; Dimachkie, Ziad O.; Golas, Avantika; Cheng, Alice; Parhi, Purnendu; Vogler, Erwin A.


    Sepharose ion-exchange particles bearing strong Lewis acid/base functional groups (sulfopropyl, carboxymethyl, quarternary ammonium, dimethyl aminoethyl, and iminodiacetic acid) exhibiting high plasma protein adsorbent capacities are shown to be more efficient activators of blood factor XII in neat-buffer solution than either hydrophilic clean-glass particles or hydrophobic octyl sepharose particles ( FXII→surfaceactivatorFXIIa; a.k.a autoactivation, where FXII is the zymogen and FXIIa is a p...

  8. The influence of macroeconomic factors to the dynamics of stock exchange in the republic of Kazakhstan

    Directory of Open Access Journals (Sweden)

    Shakizada Uteulievna Niyazbekova


    Full Text Available This article describes the influence of macroeconomic factors on Kazakhstan Stock Exchange Market by using data from 2005 to 2014. Engle-Granger cointegration test has shown that stock index is cointegrated with the exchange rate, interest rate, CPI and oil price. Vector error correction model has confirmed that macroeconomic variables and the stock index has a long-term equilibrium relationship. Moreover, empirical results have shown that stock index can be used as a leading indicator of the economic situation in Kazakhstan. Therefore, the authors decided to consider the impact of major macroeconomic indicators to the dynamics of the stock market of the Republic of Kazakhstan. The Engle-Granger cointegration test results show that the following variables such as exchange rate, 10-years long-term bond rate, the consumer price index and the Brent oil price are cointegrated with stock index, which means that there is a long-term relationship between this stock market index and these variables. With the help of econometric models, the authors have found the factors such as the exchange rate, the 10-year long-term bonds rate, the consumer price index and the Brent oil price (these factors have the long-term relationship with stock market index. Changes in the dynamics of the stock market index in Kazakhstan are caused by changes in the dynamics of Central bank's reserves and export. The analysis has shown that the economy of the Republic of Kazakhstan (the index reflects the situation in the real sector of the economy remains dependent on world oil prices, the volume of exports and the rate of the national currency

  9. Evidence for a pro-proliferative feedback loop in prostate cancer: the role of Epac1 and COX-2-dependent pathways.

    Directory of Open Access Journals (Sweden)

    Uma Kant Misra

    Full Text Available OBJECTIVE: In human prostate cancer cells, a selective Epac agonist, 8-CPT-2Me-cAMP, upregulates cell proliferation and survival via activation of Ras-MAPK and PI- 3-kinase-Akt-mTOR signaling cascades. Here we examine the role of inflammatory mediators in Epac1-induced cellular proliferation by determining the expression of the pro-inflammatory markers p-cPLA2, COX-2, and PGE2 in prostate cancer cells treated with 8-CPT-2Me-cAMP. METHODS: We employed inhibitors of COX-2, mTORC1, and mTORC2 to probe cyclic AMP-dependent pathways in human prostate cancer cells. RNAi targeting Epac1, Raptor, and Rictor was also employed in these studies. RESULTS: 8-CPT-2Me-cAMP treatment caused a 2-2.5-fold increase of p-cPLA2(S505, COX-2, and PGE2 levels in human prostate cancer cell lines. Pretreatment of cells with the COX-2 inhibitor SC-58125 or the EP4 antagonist AH-23848, or with an inhibitor of mTORC1 and mTORC2, Torin1, significantly reduced the Epac1-dependent increase of p-cPLA2 and COX-2, p-S6-kinase(T389, and p-AKT(S473. In addition, Epac1-induced protein and DNA synthesis were greatly reduced upon pretreatment of cells with either COX-2, EP4, or mTOR inhibitors. Transfection of prostate cancer cells with Epac1 dsRNA, Raptor dsRNA, or Rictor dsRNA profoundly reduced Epac1-dependent increases in p-cPLA2 and COX-2. CONCLUSION: We show that Epac1, a downstream effector of cAMP, functions as a pro-inflammatory modulator in prostate cancer cells and promotes cell proliferation and survival by upregulating Ras-MAPK, and PI 3-kinase-Akt-mTOR signaling.

  10. The importance of social exchange to nurses and nurse assistants: impact on retention factors. (United States)

    Trybou, Jeroen; De Pourcq, Kaat; Paeshuyse, Michel; Gemmel, Paul


    The purpose of this study was to test the norm of reciprocity by examining relationships between perceived organisational support (POS), the quality of leader-member exchange (LMX) and psychological contract breach (PCB) and important nurse retention factors identified in the literature. A major cause of turnover among nurses is related to unsatisfying workplaces. Previous research, mainly outside the nursing setting, found that social exchange affects employees' work-related attitudes. A cross-sectional survey was conducted on 217 nurses and nursing assistants to test and refine a model linking POS, LMX, PCB with job satisfaction, trust and turnover intentions. Hierarchical multiple linear regression revealed that POS, PCB and LMX explained significant variance in all three retention factors: job satisfaction (adjusted R² = 0.502), trust (adjusted R² = 0.462) and turnover intentions (adjusted R² = 0.196). POS and PCB predicted most strongly job satisfaction (P < 0.001) and trust (P < 0.001 and P < 0.01, respectively). LMX predicted most strongly intention to leave (P < 0.01). In our study, POS, the quality of LMX and PCB were strongly related to job satisfaction, trust and turnover intentions. Nursing managers and leaders should recognize the importance of social exchange within their organisation to build trust, satisfy and retain scarce nurses and nursing assistants. © 2013 John Wiley & Sons Ltd.

  11. Exchange Protein Activated by cAMP Enhances Long-Term Memory Formation Independent of Protein Kinase A (United States)

    Ma, Nan; Abel, Ted; Hernandez, Pepe J.


    It is well established that cAMP signaling within neurons plays a major role in the formation of long-term memories--signaling thought to proceed through protein kinase A (PKA). However, here we show that exchange protein activated by cAMP (Epac) is able to enhance the formation of long-term memory in the hippocampus and appears to do so…

  12. Empirical Method To Accurately Determine Peptide-Averaged Protection Factors from Hydrogen Exchange MS Data. (United States)

    Walters, Benjamin T


    Amide hydrogen exchange experiments measured by mass spectrometry have become commonplace to study protein structural dynamics; however, the underdetermined nature of these measurements render extraction of exchange rates unreliable at the level of individual peptides. This prevents orthogonal verification of results and severely limits interpretation of the data. This work describes an easy-to-implement empirical method to determine the change in an observed rate constant or the average change in multiple rate constants as compared to some reference condition. This allows direct empirical computation of the average protection factor (PF) for peptides in isolation requiring no knowledge of actual rate constants themselves. Benchmarking the method by comparison of average peptide PFs with site-resolved NMR-derived PFs demonstrates high reliability and accuracy. This empirical method provides the first universally reliable strategy for recovering subglobal structural physics from individual peptides and, in doing so, standardizes the hydrogen exchange experiments measured by bottom-up mass spectrometry (HX MS), simplifies interpretation, and facilitates clear communication of the results.

  13. Structural Dynamics Control Allosteric Activation of Cytohesin Family Arf GTPase Exchange Factors

    Energy Technology Data Exchange (ETDEWEB)

    Malaby, Andrew W.; Das, Sanchaita; Chakravarthy, Srinivas; Irving, Thomas C.; Bilsel, Osman; Lambright, David G.


    Membrane dynamic processes including vesicle biogenesis depend on Arf guanosine triphosphatase (GTPase) activation by guanine nucleotide exchange factors (GEFs) containing a catalytic Sec7 domain and a membrane-targeting module such as a pleckstrin homology (PH) domain. The catalytic output of cytohesin family Arf GEFs is controlled by autoinhibitory interactions that impede accessibility of the exchange site in the Sec7 domain. These restraints can be relieved through activator Arf-GTP binding to an allosteric site comprising the PH domain and proximal autoinhibitory elements (Sec7-PH linker and C-terminal helix). Small-angle X-ray scattering and negative-stain electron microscopy were used to investigate the structural organization and conformational dynamics of cytohesin-3 (Grp1) in autoinhibited and active states. The results support a model in which hinge dynamics in the autoinhibited state expose the activator site for Arf-GTP binding, while subsequent C-terminal helix unlatching and repositioning unleash conformational entropy in the Sec7-PH linker to drive exposure of the exchange site.

  14. Health information exchange implementation: lessons learned and critical success factors from a case study. (United States)

    Feldman, Sue S; Schooley, Benjamin L; Bhavsar, Grishma P


    statewide HIE were found. The most significant perceived success was accomplishing the implementation, although many interviewees also underscored the value of a project champion with decision-making power. In terms of lessons learned, social reasons were found to be very significant motivators for early implementation, frequently outweighing economic motivations. It was clear that understanding the guides early in the project would have mitigated some of the challenges that emerged, and early communication with the electronic health record vendor so that they have a solid understanding of the undertaking was critical. An HIE implementations evaluation framework was found to be useful for assessing challenges, motivations, value propositions for participating, and success factors to consider for future implementations. This case study illuminates five critical success factors for implementation of a health system onto a statewide HIE. This study also reveals that organizations have varied motivations and value proposition perceptions for engaging in the exchange of health information, few of which, at the early stages, are economically driven.

  15. Health Information Exchange Implementation: Lessons Learned and Critical Success Factors From a Case Study (United States)


    implementation of a health system to the statewide HIE were found. The most significant perceived success was accomplishing the implementation, although many interviewees also underscored the value of a project champion with decision-making power. In terms of lessons learned, social reasons were found to be very significant motivators for early implementation, frequently outweighing economic motivations. It was clear that understanding the guides early in the project would have mitigated some of the challenges that emerged, and early communication with the electronic health record vendor so that they have a solid understanding of the undertaking was critical. An HIE implementations evaluation framework was found to be useful for assessing challenges, motivations, value propositions for participating, and success factors to consider for future implementations. Conclusions This case study illuminates five critical success factors for implementation of a health system onto a statewide HIE. This study also reveals that organizations have varied motivations and value proposition perceptions for engaging in the exchange of health information, few of which, at the early stages, are economically driven. PMID:25599991

  16. Estimation of Hydrogen-Exchange Protection Factors from MD Simulation Based on Amide Hydrogen Bonding Analysis (United States)

    Park, In-Hee; Venable, John D.; Steckler, Caitlin; Cellitti, Susan E.; Lesley, Scott A.; Spraggon, Glen; Brock, Ansgar


    Hydrogen exchange (HX) studies have provided critical insight into our understanding of protein folding, structure and dynamics. More recently, Hydrogen Exchange Mass Spectrometry (HX-MS) has become a widely applicable tool for HX studies. The interpretation of the wealth of data generated by HX-MS experiments as well as other HX methods would greatly benefit from the availability of exchange predictions derived from structures or models for comparison with experiment. Most reported computational HX modeling studies have employed solvent-accessible-surface-area based metrics in attempts to interpret HX data on the basis of structures or models. In this study, a computational HX-MS prediction method based on classification of the amide hydrogen bonding modes mimicking the local unfolding model is demonstrated. Analysis of the NH bonding configurations from Molecular Dynamics (MD) simulation snapshots is used to determine partitioning over bonded and non-bonded NH states and is directly mapped into a protection factor (PF) using a logistics growth function. Predicted PFs are then used for calculating deuteration values of peptides and compared with experimental data. Hydrogen exchange MS data for Fatty acid synthase thioesterase (FAS-TE) collected for a range of pHs and temperatures was used for detailed evaluation of the approach. High correlation between prediction and experiment for observable fragment peptides is observed in the FAS-TE and additional benchmarking systems that included various apo/holo proteins for which literature data were available. In addition, it is shown that HX modeling can improve experimental resolution through decomposition of in-exchange curves into rate classes, which correlate with prediction from MD. Successful rate class decompositions provide further evidence that the presented approach captures the underlying physical processes correctly at the single residue level. This assessment is further strengthened in a comparison of

  17. Insights into the biological functions of Dock family guanine nucleotide exchange factors. (United States)

    Laurin, Mélanie; Côté, Jean-François


    Rho GTPases play key regulatory roles in many aspects of embryonic development, regulating processes such as differentiation, proliferation, morphogenesis, and migration. Two families of guanine nucleotide exchange factors (GEFs) found in metazoans, Dbl and Dock, are responsible for the spatiotemporal activation of Rac and Cdc42 proteins and their downstream signaling pathways. This review focuses on the emerging roles of the mammalian DOCK family in development and disease. We also discuss, when possible, how recent discoveries concerning the biological functions of these GEFs might be exploited for the development of novel therapeutic strategies.

  18. Multiple factors confer specific Cdc42 and Rac protein activation by dedicator of cytokinesis (DOCK) nucleotide exchange factors. (United States)

    Kulkarni, Kiran; Yang, Jing; Zhang, Ziguo; Barford, David


    DOCK (dedicator of cytokinesis) guanine nucleotide exchange factors (GEFs) activate the Rho-family GTPases Rac and Cdc42 to control cell migration, morphogenesis, and phagocytosis. The DOCK A and B subfamilies activate Rac, whereas the DOCK D subfamily activates Cdc42. Nucleotide exchange is catalyzed by a conserved DHR2 domain (DOCK(DHR2)). Although the molecular basis for DOCK(DHR2)-mediated GTPase activation has been elucidated through structures of a DOCK9(DHR2)-Cdc42 complex, the factors determining recognition of specific GTPases are unknown. To understand the molecular basis for DOCK-GTPase specificity, we have determined the crystal structure of DOCK2(DHR2) in complex with Rac1. DOCK2(DHR2) and DOCK9(DHR2) exhibit similar tertiary structures and homodimer interfaces and share a conserved GTPase-activating mechanism. Multiple structural differences between DOCK2(DHR2) and DOCK9(DHR2) account for their selectivity toward Rac1 and Cdc42. Key determinants of selectivity of Cdc42 and Rac for their cognate DOCK(DHR2) are a Phe or Trp residue within β3 (residue 56) and the ability of DOCK proteins to exploit differences in the GEF-induced conformational changes of switch 1 dependent on a divergent residue at position 27. DOCK proteins, therefore, differ from DH-PH GEFs that select their cognate GTPases through recognition of structural differences within the β2/β3 strands.

  19. Evaluation of Pump Discontinuation and Associated Factors in the T1D Exchange Clinic Registry. (United States)

    Wong, Jenise C; Boyle, Claire; DiMeglio, Linda A; Mastrandrea, Lucy D; Abel, Kimber-Lee; Cengiz, Eda; Cemeroglu, Pinar A; Aleppo, Grazia; Largay, Joseph F; Foster, Nicole C; Beck, Roy W; Adi, Saleh


    The objectives of this study were to examine factors associated with insulin pump discontinuation among children and adults followed longitudinally for 1 year in the multicenter T1D Exchange clinic registry, and to provide participant-reported reasons for stopping pump therapy. We longitudinally followed 8935 participants of all ages using an insulin pump at the time of registry enrollment. Logistic regressions were used to identify demographic and clinical factors associated with pump discontinuation. Pump discontinuation was self-reported by participants on a first annual follow-up survey. The overall frequency of pump discontinuation was 3%. Discontinuation was higher in adolescents (4%) and young adults (4%) than in younger children (3%) or older adults (1%). In multivariate analysis of children between 6 and pump use were more likely to have higher HbA1c levels at baseline (adjusted P pump included problems with wearability (57%), disliking the pump or feeling anxious (44%), and problems with glycemic control (30%). In T1D Exchange registry participants, insulin pump discontinuation is uncommon, but more prevalent among adolescents and young adults, and youth with poor glycemic control. Given the known benefits of pump therapy, these populations should be targeted for support and education on troubleshooting pump use. Common reasons for discontinuation should also be considered in future device design and technological improvement.

  20. Porphyromonas gingivalis Uses Specific Domain Rearrangements and Allelic Exchange to Generate Diversity in Surface Virulence Factors (United States)

    Dashper, Stuart G.; Mitchell, Helen L.; Seers, Christine A.; Gladman, Simon L.; Seemann, Torsten; Bulach, Dieter M.; Chandry, P. Scott; Cross, Keith J.; Cleal, Steven M.; Reynolds, Eric C.


    Porphyromonas gingivalis is a keystone pathogen of chronic periodontitis. The virulence of P. gingivalis is reported to be strain related and there are currently a number of strain typing schemes based on variation in capsular polysaccharide, the major and minor fimbriae and adhesin domains of Lys-gingipain (Kgp), amongst other surface proteins. P. gingivalis can exchange chromosomal DNA between strains by natural competence and conjugation. The aim of this study was to determine the genetic variability of P. gingivalis strains sourced from international locations over a 25-year period and to determine if variability in surface virulence factors has a phylogenetic basis. Whole genome sequencing was performed on 13 strains and comparison made to 10 previously sequenced strains. A single nucleotide polymorphism-based phylogenetic analysis demonstrated a shallow tri-lobed phylogeny. There was a high level of reticulation in the phylogenetic network, demonstrating extensive horizontal gene transfer between the strains. Two highly conserved variants of the catalytic domain of the major virulence factor the Kgp proteinase (KgpcatI and KgpcatII) were found. There were three variants of the fourth Kgp C-terminal cleaved adhesin domain. Specific variants of the cell surface proteins FimA, FimCDE, MfaI, RagAB, Tpr, and PrtT were also identified. The occurrence of all these variants in the P. gingivalis strains formed a mosaic that was not related to the SNP-based phylogeny. In conclusion P. gingivalis uses domain rearrangements and genetic exchange to generate diversity in specific surface virulence factors. PMID:28184216

  1. The Golgi apparatus is a functionally distinct Ca2+ store regulated by PKA and Epac branches of the β1-adrenergic signaling pathway (United States)

    Yang, Zhaokang.; Kirton, Hannah M.; MacDougall, David A.; Boyle, John P.; Deuchars, James; Frater, Brenda; Ponnambalam, Sreenivasan; Hardy, Matthew E.; White, Edward; Calaghan, Sarah C.; Peers, Chris; Steele, Derek S.


    Ca2+ release from the Golgi apparatus regulates key functions of the organelle, including vesicle trafficking. However, the signaling pathways that control this form of Ca2+ release are poorly understood and evidence of discrete Golgi Ca2+ release events is lacking. Here, we identified the Golgi apparatus as the source of prolonged Ca2+ release events that originate from the nuclear ‘poles’ of primary cardiac cells. Once initiated, Golgi Ca2+ release was unaffected by global depletion of sarcoplasmic reticulum Ca2+, and disruption of the Golgi apparatus abolished Golgi Ca2+ release without affecting sarcoplasmic reticulum function, suggesting functional and anatomical independence of Golgi and sarcoplasmic reticulum Ca2+ stores. Maximal activation of β1-adrenoceptors had only a small stimulating effect on Golgi Ca2+ release. However, inhibition of phosphodiesterase (PDE) 3 or 4, or downregulation of PDE 3 and 4 in heart failure markedly potentiated β1-adrenergic stimulation of Golgi Ca2+ release, consistent with compartmentalization of cAMP signaling within the Golgi apparatus microenvironment. β1-adrenergic stimulation of Golgi Ca2+ release involved activation of both Epac and PKA signaling pathways and CaMKII. Interventions that stimulated Golgi Ca2+ release induced trafficking of vascular growth factor receptor-1 (VEGFR-1) from the Golgi apparatus to the surface membrane. These data establish the Golgi apparatus as a juxtanuclear focal point for Ca2+ and β1-adrenergic signaling, which functions independently from the sarcoplasmic reticulum and the global Ca2+ transients that underlie the primary contractile function of the cell. PMID:26462734

  2. The minimal autoinhibited unit of the guanine nucleotide exchange factor intersectin.

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    K Farid Ahmad

    Full Text Available Intersectin-1L is a member of the Dbl homology (DH domain guanine nucleotide exchange factors (GEF which control Rho-family GTPase signaling. Intersectin-1L is a GEF that is specific for Cdc42. It plays an important role in endocytosis, and is regulated by several partners including the actin regulator N-WASP. Intact intersectin-1L shows low Cdc42 exchange activity, although the isolated catalytic DH domain shows high activity. This finding suggests that the molecule is autoinhibited. To investigate the mechanism of autoinhibition we have constructed a series of domain deletions. We find that the five SH3 domains of intersectin are important for autoinhibition, with the fifth domain (SH3(E being sufficient for the bulk of the autoinhibitory effect. This SH3 domain appears to primarily interact with the DH domain. We have determined the crystal structure of the SH3(E-DH domain construct, which shows a domain swapped arrangement in which the SH3 from one monomer interacts with the DH domain of the other monomer. Analytical ultracentrifugation and gel filtration, however, show that under biochemical concentrations, the construct is fully monomeric. Thus we propose that the actual autoinhibited structure contains the related intramolecular SH3(E-DH interaction. We propose a model in which this intramolecular interaction may block or distort the GTPase binding region of the DH domain.

  3. Studies on Some Factors Affecting the Quantitative Estimation of the Exchange Capacity of Organic Matter (United States)

    Walter M. Broadfoot; Edward H. Tyner


    Methods which are satisfactory for determining the base-exchange capacity of mineral soils can not be applied indiscriminately for determining the exchange capacity of fresh or decomposed plant residues.

  4. Nucleocytoplasmic shuttling of the Cdc42p exchange factor Cdc24p. (United States)

    Nern, A; Arkowitz, R A


    Cdc24p, the GDP/GTP exchange factor for the regulator of actin cytoskeleton Cdc42p, localizes to sites of polarized growth. Here we show that Cdc24p shuttles in and out of the yeast nucleus during vegetative growth. Far1p is necessary and sufficient for nuclear accumulation of Cdc24p, suggesting that its nuclear import occurs via an association with Far1p. Nuclear export is triggered either by entry into the cell cycle or by mating pheromone. As Far1p is degraded upon entry into the cell cycle, cell cycle-dependent export of Cdc24p occurs in the absence of Far1p, whereas during mating similar export kinetics indicate that a Cdc24p-Far1p complex is exported. Our results suggest that the nucleus serves as a store of preformed Cdc24p-Far1p complex which is required for chemotropism.

  5. An investigation on important factors influencing on forecasted earnings adjustment: Evidence from Tehran Stock Exchange

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    Fatemeh Babakhani


    Full Text Available This paper presents an empirical investigation to detect important factors influencing earning adjustment on firms selected on Tehran Stock Exchange over the period 2006-2011. There are four independent variables associated with the proposed study of this paper including Proportion of shares owned by institutional investors, Return on assets, Profit change and Market value to book value. In addition, Investment restructuring is considered as control variable. The results of the implementation of regression analysis indicate that there was a reverse relationship between earning forecasted adjustment and two independent variables including size of firm as well as the ratio of market value to book value. However, Net profit has a direct and positive relationship with earning forecast adjustment.

  6. Zizimin and Dock guanine nucleotide exchange factors in cell function and disease. (United States)

    Pakes, Nicholl K; Veltman, Douwe M; Williams, Robin S B


    Zizimin proteins belong to the Dock (Dedicator of Cytokinesis) superfamily of Guanine nucleotide Exchange Factor (GEF) proteins. This family of proteins plays a role in the regulation of Rho family small GTPases. Together the Rho family of small GTPases and the Dock/Zizimin proteins play a vital role in a number of cell processes including cell migration, apoptosis, cell division and cell adhesion. Our recent studies of Zizimin proteins, using a simple biomedical model, the eukaryotic social amoeba Dictyostelium discoideum, have helped to elucidate the cellular role of these proteins. In this article, we discuss the domain structure of Zizimin proteins from an evolutionary viewpoint. We also compare what is currently known about the mammalian Zizimin proteins to that of related Dock proteins. Understanding the cellular functions of these proteins will provide a better insight into their role in cell signaling, and may help in treating disease pathology associated with mutations in Dock/Zizimin proteins.

  7. The signaling module cAMP/Epac/Rap1/PLCε/IP3 mobilizes acrosomal calcium during sperm exocytosis. (United States)

    Lucchesi, Ornella; Ruete, María C; Bustos, Matías A; Quevedo, María F; Tomes, Claudia N


    Exocytosis of the sperm's single secretory granule, or acrosome, is a regulated exocytosis triggered by components of the egg's investments. In addition to external calcium, sperm exocytosis (termed the acrosome reaction) requires cAMP synthesized endogenously and calcium mobilized from the acrosome through IP3-sensitive channels. The relevant cAMP target is Epac. In the first part of this paper, we present a novel tool (the TAT-cAMP sponge) to investigate cAMP-related signaling pathways in response to progesterone as acrosome reaction trigger. The TAT-cAMP sponge consists of the cAMP-binding sites of protein kinase A regulatory subunit RIβ fused to the protein transduction domain TAT of the human immunodeficiency virus-1. The sponge permeated into sperm, sequestered endogenous cAMP, and blocked exocytosis. Progesterone increased the population of sperm with Rap1-GTP, Rab3-GTP, and Rab27-GTP in the acrosomal region; pretreatment with the TAT-cAMP sponge prevented the activation of all three GTPases. In the second part of this manuscript, we show that phospholipase Cε (PLCε) is required for the acrosome reaction downstream of Rap1 and upstream of intra-acrosomal calcium mobilization. Last, we present direct evidence that cAMP, Epac, Rap1, and PLCε are necessary for calcium mobilization from sperm's secretory granule. In summary, we describe here a pathway that connects cAMP to calcium mobilization from the acrosome during sperm exocytosis. Never before had direct evidence for each step of the cascade been put together in the same study. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Activation of GPR4 by Acidosis Increases Endothelial Cell Adhesion through the cAMP/Epac Pathway (United States)

    Leffler, Nancy R.; Asch, Adam S.; Witte, Owen N.; Yang, Li V.


    Endothelium-leukocyte interaction is critical for inflammatory responses. Whereas the tissue microenvironments are often acidic at inflammatory sites, the mechanisms by which cells respond to acidosis are not well understood. Using molecular, cellular and biochemical approaches, we demonstrate that activation of GPR4, a proton-sensing G protein-coupled receptor, by isocapnic acidosis increases the adhesiveness of human umbilical vein endothelial cells (HUVECs) that express GPR4 endogenously. Acidosis in combination with GPR4 overexpression further augments HUVEC adhesion with U937 monocytes. In contrast, overexpression of a G protein signaling-defective DRY motif mutant (R115A) of GPR4 does not elicit any increase of HUVEC adhesion, indicating the requirement of G protein signaling. Downregulation of GPR4 expression by RNA interference reduces the acidosis-induced HUVEC adhesion. To delineate downstream pathways, we show that inhibition of adenylate cyclase by inhibitors, 2′,5′-dideoxyadenosine (DDA) or SQ 22536, attenuates acidosis/GPR4-induced HUVEC adhesion. Consistently, treatment with a cAMP analog or a Gi signaling inhibitor increases HUVEC adhesiveness, suggesting a role of the Gs/cAMP signaling in this process. We further show that the cAMP downstream effector Epac is important for acidosis/GPR4-induced cell adhesion. Moreover, activation of GPR4 by acidosis increases the expression of vascular adhesion molecules E-selectin, VCAM-1 and ICAM-1, which are functionally involved in acidosis/GPR4-mediated HUVEC adhesion. Similarly, hypercapnic acidosis can also activate GPR4 to stimulate HUVEC adhesion molecule expression and adhesiveness. These results suggest that acidosis/GPR4 signaling regulates endothelial cell adhesion mainly through the Gs/cAMP/Epac pathway and may play a role in the inflammatory response of vascular endothelial cells. PMID:22110680

  9. The Guanine Nucleotide Exchange Factor ARNO mediates the activation of ARF and phospholipase D by insulin

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    Fluharty Eric


    Full Text Available Abstract Background Phospholipase D (PLD is involved in many signaling pathways. In most systems, the activity of PLD is primarily regulated by the members of the ADP-Ribosylation Factor (ARF family of GTPases, but the mechanism of activation of PLD and ARF by extracellular signals has not been fully established. Here we tested the hypothesis that ARF-guanine nucleotide exchange factors (ARF-GEFs of the cytohesin/ARNO family mediate the activation of ARF and PLD by insulin. Results Wild type ARNO transiently transfected in HIRcB cells was translocated to the plasma membrane in an insulin-dependent manner and promoted the translocation of ARF to the membranes. ARNO mutants: ΔCC-ARNO and CC-ARNO were partially translocated to the membranes while ΔPH-ARNO and PH-ARNO could not be translocated to the membranes. Sec7 domain mutants of ARNO did not facilitate the ARF translocation. Overexpression of wild type ARNO significantly increased insulin-stimulated PLD activity, and mutations in the Sec7 and PH domains, or deletion of the PH or CC domains inhibited the effects of insulin. Conclusions Small ARF-GEFs of the cytohesin/ARNO family mediate the activation of ARF and PLD by the insulin receptor.

  10. Air exchanges and indoor carbon dioxide concentration in Australian pig buildings: Effect of housing and management factors

    DEFF Research Database (Denmark)

    Banhazi, T. M.; Stott, P.; Rutley, D.


    There has been a growing interest in improving air quality within livestock buildings. However, the influence of housing and management factors on air exchange rates and indoor gas concentrations is not well understood. The aim of this study was to determine the effects of housing and management...... factors on the concentrations of carbon dioxide (CO(2)) and air exchange rates in 160 representative Australian pig buildings. CO(2) concentrations were measured, air changes per hour (ACH) were estimated using a CO(2) balance method, and structural and management parameters were recorded. The mean CO(2......) concentration measured was 858 ppm and a mean air exchange rate of 22.8 ACH was estimated. The analysis showed that CO(2) concentrations were affected by the type of building, season, control of the wall and ridge vents, ceiling height, size of the wall vents and height of the ridge vents. Weaner buildings had...

  11. Exchange enhancement of the electron g-factor in a two-dimensional semimetal in HgTe quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Bovkun, L. S., E-mail:; Krishtopenko, S. S.; Zholudev, M. S.; Ikonnikov, A. V.; Spirin, K. E. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Dvoretsky, S. A.; Mikhailov, N. N. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation); Teppe, F.; Knap, W. [Universite Montpellier II, Laboratoire Charles Coulomb (L2C), UMR CNRS 5221, GIS-TERALAB (France); Gavrilenko, V. I. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)


    The exchange enhancement of the electron g-factor in perpendicular magnetic fields to 12 T in HgTe/CdHgTe quantum wells 20 nm wide with a semimetal band structure is studied. The electron effective mass and g-factor at the Fermi level are determined by analyzing the temperature dependence of the amplitude of Shubnikov–de Haas oscillation in weak fields and near odd Landau-level filling factors ν ≤ 9. The experimental values are compared with theoretical calculations performed in the one-electron approximation using the eight-band kp Hamiltonian. The found dependence of g-factor enhancement on the electron concentration is explained by changes in the contributions of hole- and electron-like states to exchange corrections to the Landau-level energies in the conduction band.

  12. Ric-8A, a Gα protein guanine nucleotide exchange factor potentiates taste receptor signaling

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    Claire J Fenech


    Full Text Available Taste receptors for sweet, bitter and umami tastants are G-protein coupled receptors (GPCRs. While much effort has been devoted to understanding G-protein-receptor interactions and identifying the components of the signalling cascade downstream of these receptors, at the level of the G-protein the modulation of receptor signal transduction remains relatively unexplored. In this regard a taste-specific regulator of G-protein signaling (RGS, RGS21, has recently been identified. To study whether guanine nucleotide exchange factors (GEFs are involved in the transduction of the signal downstream of the taste GPCRs we investigated the expression of Ric-8A and Ric-8B in mouse taste cells and their interaction with G-protein subunits found in taste buds. Mammalian Ric-8 proteins were initially identified as potent GEFs for a range of Gα subunits and Ric-8B has recently been shown to amplify olfactory signal transduction. We find that both Ric-8A and Ric-8B are expressed in a large portion of taste bud cells and that most of these cells contain IP3R-3 a marker for sweet, umami and bitter taste receptor cells. Ric-8A interacts with Gα-gustducin and Gαi2 through which it amplifies the signal transduction of hTas2R16, a receptor for bitter compounds. Overall, these findings are consistent with a role for Ric-8 in mammalian taste signal transduction.

  13. Human body area factors for radiation exchange analysis: standing and walking postures. (United States)

    Park, Sookuk; Tuller, Stanton E


    Effective radiation area factors (f (eff)) and projected area factors (f (p)) of unclothed Caucasians' standing and walking postures used in estimating human radiation exchange with the surrounding environment were determined from a sample of adults in Canada. Several three-dimensional (3D) computer body models were created for standing and walking postures. Only small differences in f (eff) and f (p) values for standing posture were found between gender (male or female) and body type (normal- or over-weight). Differences between this study and previous studies were much larger: ≤0.173 in f (p) and ≤0.101 in f (eff). Directionless f (p) values for walking posture also had only minor differences between genders and positions in a stride. However, the differences of mean directional f (p) values of the positions dependent on azimuth angles were large enough, ≤0.072, to create important differences in modeled radiation receipt. Differences in f (eff) values were small: 0.02 between the normal-weight male and female models and up to 0.033 between positions in a stride. Variations of directional f (p) values depending on solar altitudes for walking posture were narrower than those for standing posture. When both standing and walking postures are considered, the mean f (eff) value, 0.836, of standing (0.826) and walking (0.846) could be used. However, f (p) values should be selected carefully because differences between directional and directionless f (p) values were large enough that they could influence the estimated level of human thermal sensation.

  14. Non-muscle myosin II regulates neuronal actin dynamics by interacting with guanine nucleotide exchange factors.

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    Eun-Young Shin

    Full Text Available BACKGROUND: Non-muscle myosin II (NM II regulates a wide range of cellular functions, including neuronal differentiation, which requires precise spatio-temporal activation of Rho GTPases. The molecular mechanism underlying the NM II-mediated activation of Rho GTPases is poorly understood. The present study explored the possibility that NM II regulates neuronal differentiation, particularly morphological changes in growth cones and the distal axon, through guanine nucleotide exchange factors (GEFs of the Dbl family. PRINCIPAL FINDINGS: NM II colocalized with GEFs, such as βPIX, kalirin and intersectin, in growth cones. Inactivation of NM II by blebbistatin (BBS led to the increased formation of short and thick filopodial actin structures at the periphery of growth cones. In line with these observations, FRET analysis revealed enhanced Cdc42 activity in BBS-treated growth cones. BBS treatment also induced aberrant targeting of various GEFs to the distal axon where GEFs were seldom observed under physiological conditions. As a result, numerous protrusions and branches were generated on the shaft of the distal axon. The disruption of the NM II-GEF interactions by overexpression of the DH domains of βPIX or Tiam1, or by βPIX depletion with specific siRNAs inhibited growth cone formation and induced slender axons concomitant with multiple branches in cultured hippocampal neurons. Finally, stimulation with nerve growth factor induced transient dissociation of the NM II-GEF complex, which was closely correlated with the kinetics of Cdc42 and Rac1 activation. CONCLUSION: Our results suggest that NM II maintains proper morphology of neuronal growth cones and the distal axon by regulating actin dynamics through the GEF-Rho GTPase signaling pathway.


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    P. Raveendiran


    Full Text Available The heat transfer coefficients and friction factors of a baffled shell and heat pipe heat exchanger with various inclination angles were determined experimentally; using methanol as working fluid and water as heat transport fluid were reported. Heat pipe heat exchanger reported in this investigation have inclination angles varied between 15o and 60o for different mass flow rates and temperature at the shell side of the heat exchanger. All the required parameters like outlet temperature of both hot and cold side of heat exchanger and mass flow rate of fluids were measured using an appropriate instrument. Different tests were performed from which condenser side heat transfer coefficient and friction factor were calculated. In all operating conditions it has been found that the heat transfer coefficient increases by increasing the mass flow rate and angle of inclination. The reduction in friction factor occurs when the Reynolds number is increased. The overall optimum experimental effectiveness of GABSHPHE has found to be 42% in all operating conditioning at ψ = 45o.

  16. Activation of protein kinase A and exchange protein directly activated by cAMP promotes adipocyte differentiation of human mesenchymal stem cells

    DEFF Research Database (Denmark)

    Jia, Bingbing; Madsen, Lise; Petersen, Rasmus Koefoed


    Human mesenchymal stem cells are primary multipotent cells capable of differentiating into several cell types including adipocytes when cultured under defined in vitro conditions. In the present study we investigated the role of cAMP signaling and its downstream effectors, protein kinase A (PKA......) and exchange protein directly activated by cAMP (Epac) in adipocyte conversion of human mesenchymal stem cells derived from adipose tissue (hMADS). We show that cAMP signaling involving the simultaneous activation of both PKA- and Epac-dependent signaling is critical for this process even in the presence...... of the strong adipogenic inducers insulin, dexamethasone, and rosiglitazone, thereby clearly distinguishing the hMADS cells from murine preadipocytes cell lines, where rosiglitazone together with dexamethasone and insulin strongly promotes adipocyte differentiation. We further show that prostaglandin I(2) (PGI...

  17. The guanine nucleotide exchange factor RIC8 regulates conidial germination through Gα proteins in Neurospora crassa.

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    Carla J Eaton

    Full Text Available Heterotrimeric G protein signaling is essential for normal hyphal growth in the filamentous fungus Neurospora crassa. We have previously demonstrated that the non-receptor guanine nucleotide exchange factor RIC8 acts upstream of the Gα proteins GNA-1 and GNA-3 to regulate hyphal extension. Here we demonstrate that regulation of hyphal extension results at least in part, from an important role in control of asexual spore (conidia germination. Loss of GNA-3 leads to a drastic reduction in conidial germination, which is exacerbated in the absence of GNA-1. Mutation of RIC8 leads to a reduction in germination similar to that in the Δgna-1, Δgna-3 double mutant, suggesting that RIC8 regulates conidial germination through both GNA-1 and GNA-3. Support for a more significant role for GNA-3 is indicated by the observation that expression of a GTPase-deficient, constitutively active gna-3 allele in the Δric8 mutant leads to a significant increase in conidial germination. Localization of the three Gα proteins during conidial germination was probed through analysis of cells expressing fluorescently tagged proteins. Functional TagRFP fusions of each of the three Gα subunits were constructed through insertion of TagRFP in a conserved loop region of the Gα subunits. The results demonstrated that GNA-1 localizes to the plasma membrane and vacuoles, and also to septa throughout conidial germination. GNA-2 and GNA-3 localize to both the plasma membrane and vacuoles during early germination, but are then found in intracellular vacuoles later during hyphal outgrowth.

  18. The GDP-GTP exchange factor collybistin: an essential determinant of neuronal gephyrin clustering. (United States)

    Harvey, Kirsten; Duguid, Ian C; Alldred, Melissa J; Beatty, Sarah E; Ward, Hamish; Keep, Nicholas H; Lingenfelter, Sue E; Pearce, Brian R; Lundgren, Johan; Owen, Michael J; Smart, Trevor G; Lüscher, Bernhard; Rees, Mark I; Harvey, Robert J


    Glycine receptors (GlyRs) and specific subtypes of GABA(A) receptors are clustered at synapses by the multidomain protein gephyrin, which in turn is translocated to the cell membrane by the GDP-GTP exchange factor collybistin. We report the characterization of several new variants of collybistin, which are created by alternative splicing of exons encoding an N-terminal src homology 3 (SH3) domain and three alternate C termini (CB1, CB2, and CB3). The presence of the SH3 domain negatively regulates the ability of collybistin to translocate gephyrin to submembrane microaggregates in transfected mammalian cells. Because the majority of native collybistin isoforms appear to harbor the SH3 domain, this suggests that collybistin activity may be regulated by protein-protein interactions at the SH3 domain. We localized the binding sites for collybistin and the GlyR beta subunit to the C-terminal MoeA homology domain of gephyrin and show that multimerization of this domain is required for collybistin-gephyrin and GlyR-gephyrin interactions. We also demonstrate that gephyrin clustering in recombinant systems and cultured neurons requires both collybistin-gephyrin interactions and an intact collybistin pleckstrin homology domain. The vital importance of collybistin for inhibitory synaptogenesis is underlined by the discovery of a mutation (G55A) in exon 2 of the human collybistin gene (ARHGEF9) in a patient with clinical symptoms of both hyperekplexia and epilepsy. The clinical manifestation of this collybistin missense mutation may result, at least in part, from mislocalization of gephyrin and a major GABA(A) receptor subtype.

  19. The C-terminal Helix of Pseudomonas aeruginosa Elongation Factor Ts Tunes EF-Tu Dynamics to Modulate Nucleotide Exchange* (United States)

    De Laurentiis, Evelina Ines; Mercier, Evan; Wieden, Hans-Joachim


    Little is known about the conservation of critical kinetic parameters and the mechanistic strategies of elongation factor (EF) Ts-catalyzed nucleotide exchange in EF-Tu in bacteria and particularly in clinically relevant pathogens. EF-Tu from the clinically relevant pathogen Pseudomonas aeruginosa shares over 84% sequence identity with the corresponding elongation factor from Escherichia coli. Interestingly, the functionally closely linked EF-Ts only shares 55% sequence identity. To identify any differences in the nucleotide binding properties, as well as in the EF-Ts-mediated nucleotide exchange reaction, we performed a comparative rapid kinetics and mutagenesis analysis of the nucleotide exchange mechanism for both the E. coli and P. aeruginosa systems, identifying helix 13 of EF-Ts as a previously unnoticed regulatory element in the nucleotide exchange mechanism with species-specific elements. Our findings support the base side-first entry of the nucleotide into the binding pocket of the EF-Tu·EF-Ts binary complex, followed by displacement of helix 13 and rapid binding of the phosphate side of the nucleotide, ultimately leading to the release of EF-Ts. PMID:27624934

  20. The positive transcription factor of the 5S RNA gene proteolyses during direct exchange between 5S DNA sites



    We have examined the association, dissociation, and exchange of the 5S specific transcription factor (TFIIIA) with somatic- and oocyte-type 5S DNA. The factor associates faster with somatic than with oocyte 5S DNA, and the rate of complex formation is accelerated by vector DNA. Once formed, the TFIIIA-5S DNA complex is stable for greater than 4 h in the absence of free 5S DNA, and its dissociation is identical for somatic and for oocyte 5S DNA. In the presence of free 5S DNA, the factor trans...

  1. Effect of market factors on the short-time pricing of stock-exchange metals (United States)

    Bogdanov, S. V.; Shevelev, I. M.; Chernyi, S. A.


    The open trade on the world market is estimated using information of one-day exchange prices of nonferrous and precious metals, oil, reduced crude, and gasoline and the main world stock indices in the time period from January 1, 2009 to December 31, 2015. It is found that the short-term changes in the prices of nonferrous metals are determined by the prices on the metal market. The changes in the prices of energy carriers and the stock trade on the stock market weakly influence the pricing of nonferrous and precious metals. The prices of metals depend on the situation during trade on commodity exchanges, and the stock market indirectly influences the exchange prices of metals through changes in the share prices of the companies that produce copper, aluminum, and zinc.

  2. Epac-Rap1-activated mesenchymal stem cells improve cardiac function in rat model of myocardial infarction. (United States)

    Khan, Irfan; Ali, Anwar; Akhter, Muhammad Aleem; Naeem, Nadia; Chotani, Maqsood Ahmed; Iqbal, Hana'a; Kabir, Nurul; Atiq, Mehnaz; Salim, Asmat


    Rap1, a member of Ras superfamily of small GTP-binding proteins, is involved in cardiovascular biology in numerous ways. It is an evolutionary conserved regulator of adhesion, polarity, differentiation and growth. Our aim was to analyze Rap1-activated rat bone marrow mesenchymal stem cells (MSCs) for their potential role in adhesion and cardiac differentiation. Myocardial infarction (MI) was produced in Sprague Dawley (SD) rats through occlusion of the left anterior descending coronary artery. MSCs were treated with 8-pCPT-2'-O-Me-cAMP (CPT) to activate Rap1. Normal (untreated) and CPT-treated MSCs were transplanted through intramyocardial injection in respective groups. Cardiac function was assessed by echocardiography at 2 and 4 weeks after cell transplantation. Histological analysis was performed to observe changes at tissue level. Homing of CPT-treated MSCs was significantly (***Pinfarcted hearts. This may be due to increase in the gene expression of some of the cell adhesion molecules as evident by qRT-PCR analysis. Significant (***Ptherapy groups showed significant increase as compared to MI model. Our findings showed that pharmacological activation of Epac-Rap1 improves cardiac function through better survival, adhesion and differentiation of transplanted cells. Transplantation of these MSCs in the infarct area restored functional myocardium. © 2016 John Wiley & Sons Ltd.

  3. Indicators of exchange of bile pigments under the action of ecopathogenic factors on the organism and correction with liposomes

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    D. O. Melnychuk


    Full Text Available High levels of anthropogenic impact on the environment requires a detailed study of the features of the influence of heavy metals and ionizing radiation on living organisms, and provides for the development and use of effective means of protecting the body from its negative influence. The purpose of the work was to study the characteristics of the exchange of bile pigments of rats under the action of eсopathogenic factors (ionizing radiation and cadmium on the organism and the corrective properties of liposomes on the basis of milk phospholipids. An analysis of the chromatographic studies of bilirubin and derivatives (nonconjugated bilirubin, bilirubin sulfate, billirubin glucuronide, urobilin and stercobilin in the whole blood, liver, jejunum contents and feces under the action on the animal organism of eсopathogenic factors (ionizing radiation and cadmium indicate material violation of the exchange bile pigments that may be due to the destabilization of the structural and functional hot hepatocytes. Correction of the liposomal form of biologically active additive (BAA FLP-MD is reco­mmended; the latter is a mixture of phospholipids isolated from milk, with a mixture of unsaturated fatty acids (oleic, linoleic, linolenic and antioxidants (α-tocopherol and retinol acetate. The additive components exhibit the reparative effect of the action in respect of the damaged membrane structures with simultaneous improving of cholepoietic and billiation liver function, and therefore contribute to the normalization of exchange og bile pigments in terms of action on the body ecopathogenic factors.

  4. 75 FR 62137 - Notice of Public Meeting; Proposed Alluvial Valley Floor Coal Exchange Public Interest Factors... (United States)


    ...The Bureau of Land Management (BLM) hereby notifies the public that it will hold a public meeting to consider a proposal to exchange Federal coal deposits for Alluvial Valley Floor (AVF) fee coal pursuant to the Federal Land Policy and Management Act (FLPMA) of 1976, as amended, and the Surface Mining Control and Reclamation Act (SMCRA) of 1977. This exchange (serial number MTM-99236) has been proposed by Jay Nance, Brett A. Boedecker, as personal representative for Susanne N. Boedecker, Joseph P. Hayes, Patricia Hayes Rodolph, and the Brown Cattle Company Shareholders Coal Trust, collectively referred to as Nance-Brown.

  5. Slowed conduction and thin myelination of peripheral nerves associated with mutant rho Guanine-nucleotide exchange factor 10. (United States)

    Verhoeven, Kristien; De Jonghe, Peter; Van de Putte, Tom; Nelis, Eva; Zwijsen, An; Verpoorten, Nathalie; De Vriendt, Els; Jacobs, An; Van Gerwen, Veerle; Francis, Annick; Ceuterick, Chantal; Huylebroeck, Danny; Timmerman, Vincent


    Slowed nerve-conduction velocities (NCVs) are a biological endophenotype in the majority of the hereditary motor and sensory neuropathies (HMSN). Here, we identified a family with autosomal dominant segregation of slowed NCVs without the clinical phenotype of HMSN. Peripheral-nerve biopsy showed predominantly thinly myelinated axons. We identified a locus at 8p23 and a Thr109Ile mutation in ARHGEF10, encoding a guanine-nucleotide exchange factor (GEF) for the Rho family of GTPase proteins (RhoGTPases). Rho GEFs are implicated in neural morphogenesis and connectivity and regulate the activity of small RhoGTPases by catalyzing the exchange of bound GDP by GTP. Expression analysis of ARHGEF10, by use of its mouse orthologue Gef10, showed that it is highly expressed in the peripheral nervous system. Our data support a role for ARHGEF10 in developmental myelination of peripheral nerves.

  6. Factors affecting the exchange of genetic material between Nordic and US Holstein populatons

    DEFF Research Database (Denmark)

    Buch, L H; Sørensen, A C; Lassen, J


    be explained by differences in economic values, trait definitions, national genetic evaluation procedures, and genotype x environment interactions. The objective of this study was to test whether uniform definitions of the female fertility traits would increase the exchange of genes across populations......, and to quantify the effect on genetic gain. A second objective was to test whether a more similar relative weighting of the index traits across populations would increase the exchange of genes across populations, and to quantify the effect on genetic gain. This was done in a stochastic simulation study...... of the Nordic and US Holstein populations. Uniform definitions of the female fertility traits did not increase total genetic gain in the Nordic Holstein population. The standardization did not seem to affect selection across populations either. However, the results were sensitive to the assumptions made...

  7. The alternative Epac/cAMP pathway and the MAPK pathway mediate hCG induction of leptin in placental cells.

    Directory of Open Access Journals (Sweden)

    Julieta Lorena Maymó

    Full Text Available Pleiotropic effects of leptin have been identified in reproduction and pregnancy, particularly in the placenta, where it works as an autocrine hormone. In this work, we demonstrated that human chorionic gonadotropin (hCG added to JEG-3 cell line or to placental explants induces endogenous leptin expression. We also found that hCG increased cAMP intracellular levels in BeWo cells in a dose-dependent manner, stimulated cAMP response element (CRE activity and the cotransfection with an expression plasmid of a dominant negative mutant of CREB caused a significant inhibition of hCG stimulation of leptin promoter activity. These results demonstrate that hCG indeed activates cAMP/PKA pathway, and that this pathway is involved in leptin expression. Nevertheless, we found leptin induction by hCG is dependent on cAMP levels. Treatment with (Bu(2cAMP in combination with low and non stimulatory hCG concentrations led to an increase in leptin expression, whereas stimulatory concentrations showed the opposite effect. We found that specific PKA inhibition by H89 caused a significant increase of hCG leptin induction, suggesting that probably high cAMP levels might inhibit hCG effect. It was found that hCG enhancement of leptin mRNA expression involved the MAPK pathway. In this work, we demonstrated that hCG leptin induction through the MAPK signaling pathway is inhibited by PKA. We observed that ERK1/2 phosphorylation increased when hCG treatment was combined with H89. In view of these results, the involvement of the alternative cAMP/Epac signaling pathway was studied. We observed that a cAMP analogue that specifically activates Epac (CPT-OMe stimulated leptin expression by hCG. In addition, the overexpression of Epac and Rap1 proteins increased leptin promoter activity and enhanced hCG. In conclusion, we provide evidence suggesting that hCG induction of leptin gene expression in placenta is mediated not only by activation of the MAPK signaling pathway but also

  8. The Alternative Epac/cAMP Pathway and the MAPK Pathway Mediate hCG Induction of Leptin in Placental Cells (United States)

    Maymó, Julieta Lorena; Pérez Pérez, Antonio; Maskin, Bernardo; Dueñas, José Luis; Calvo, Juan Carlos; Sánchez Margalet, Víctor; Varone, Cecilia Laura


    Pleiotropic effects of leptin have been identified in reproduction and pregnancy, particularly in the placenta, where it works as an autocrine hormone. In this work, we demonstrated that human chorionic gonadotropin (hCG) added to JEG-3 cell line or to placental explants induces endogenous leptin expression. We also found that hCG increased cAMP intracellular levels in BeWo cells in a dose-dependent manner, stimulated cAMP response element (CRE) activity and the cotransfection with an expression plasmid of a dominant negative mutant of CREB caused a significant inhibition of hCG stimulation of leptin promoter activity. These results demonstrate that hCG indeed activates cAMP/PKA pathway, and that this pathway is involved in leptin expression. Nevertheless, we found leptin induction by hCG is dependent on cAMP levels. Treatment with (Bu)2cAMP in combination with low and non stimulatory hCG concentrations led to an increase in leptin expression, whereas stimulatory concentrations showed the opposite effect. We found that specific PKA inhibition by H89 caused a significant increase of hCG leptin induction, suggesting that probably high cAMP levels might inhibit hCG effect. It was found that hCG enhancement of leptin mRNA expression involved the MAPK pathway. In this work, we demonstrated that hCG leptin induction through the MAPK signaling pathway is inhibited by PKA. We observed that ERK1/2 phosphorylation increased when hCG treatment was combined with H89. In view of these results, the involvement of the alternative cAMP/Epac signaling pathway was studied. We observed that a cAMP analogue that specifically activates Epac (CPT-OMe) stimulated leptin expression by hCG. In addition, the overexpression of Epac and Rap1 proteins increased leptin promoter activity and enhanced hCG. In conclusion, we provide evidence suggesting that hCG induction of leptin gene expression in placenta is mediated not only by activation of the MAPK signaling pathway but also by the

  9. Study on the Influential Factors of Heat Transfer of Ground Heat Exchanger with Orthogonal Test (United States)

    Su, Shunyu; Yang, Rui; Liu, Lamei; Zhou, Chuanhui; Shi, Lei


    Orthogonal test method could decrease experimental times and obtain better test effect. The Taguchi method, as well as mean value response and analysis of variance, were applied in this paper to study the influence of water flow velocity in pipe, diameter and water temperature of pipe inlet on heat transfer of ground heat exchanger. The optimum design parameters and the estimated values of heat flux per meter of well depth for single U-tubes are obtained. The analysis revealed that diameter is the most influential parameter for heat flux per meter of well depth in single U-tubes while water flow velocity within 0.3m/s to 0.5m/s. And water flow velocity and diameter are important influential parameters for heat flux per meter of well depth in single U-tubes while water flow velocity within 0.5m/s to 0.8m/s. Tubes with big diameters are superior to tubes with small diameters in the design of ground source heat exchanger with single U-tubes.

  10. Health information exchange technology on the front lines of healthcare: workflow factors and patterns of use (United States)

    Johnson, Kevin B; Lorenzi, Nancy M


    Objective The goal of this study was to develop an in-depth understanding of how a health information exchange (HIE) fits into clinical workflow at multiple clinical sites. Materials and Methods The ethnographic qualitative study was conducted over a 9-month period in six emergency departments (ED) and eight ambulatory clinics in Memphis, Tennessee, USA. Data were collected using direct observation, informal interviews during observation, and formal semi-structured interviews. The authors observed for over 180 h, during which providers used the exchange 130 times. Results HIE-related workflow was modeled for each ED site and ambulatory clinic group and substantial site-to-site workflow differences were identified. Common patterns in HIE-related workflow were also identified across all sites, leading to the development of two role-based workflow models: nurse based and physician based. The workflow elements framework was applied to the two role-based patterns. An in-depth description was developed of how providers integrated HIE into existing clinical workflow, including prompts for HIE use. Discussion Workflow differed substantially among sites, but two general role-based HIE usage models were identified. Although providers used HIE to improve continuity of patient care, patient–provider trust played a significant role. Types of information retrieved related to roles, with nurses seeking to retrieve recent hospitalization data and more open-ended usage by nurse practitioners and physicians. User and role-specific customization to accommodate differences in workflow and information needs may increase the adoption and use of HIE. Conclusion Understanding end users' perspectives towards HIE technology is crucial to the long-term success of HIE. By applying qualitative methods, an in-depth understanding of HIE usage was developed. PMID:22003156

  11. Health information exchange technology on the front lines of healthcare: workflow factors and patterns of use. (United States)

    Unertl, Kim M; Johnson, Kevin B; Lorenzi, Nancy M


    The goal of this study was to develop an in-depth understanding of how a health information exchange (HIE) fits into clinical workflow at multiple clinical sites. The ethnographic qualitative study was conducted over a 9-month period in six emergency departments (ED) and eight ambulatory clinics in Memphis, Tennessee, USA. Data were collected using direct observation, informal interviews during observation, and formal semi-structured interviews. The authors observed for over 180 h, during which providers used the exchange 130 times. HIE-related workflow was modeled for each ED site and ambulatory clinic group and substantial site-to-site workflow differences were identified. Common patterns in HIE-related workflow were also identified across all sites, leading to the development of two role-based workflow models: nurse based and physician based. The workflow elements framework was applied to the two role-based patterns. An in-depth description was developed of how providers integrated HIE into existing clinical workflow, including prompts for HIE use. Workflow differed substantially among sites, but two general role-based HIE usage models were identified. Although providers used HIE to improve continuity of patient care, patient-provider trust played a significant role. Types of information retrieved related to roles, with nurses seeking to retrieve recent hospitalization data and more open-ended usage by nurse practitioners and physicians. User and role-specific customization to accommodate differences in workflow and information needs may increase the adoption and use of HIE. Understanding end users' perspectives towards HIE technology is crucial to the long-term success of HIE. By applying qualitative methods, an in-depth understanding of HIE usage was developed.

  12. Technology, Incentives, or Both? Factors Related to Level of Hospital Health Information Exchange. (United States)

    Lin, Sunny C; Everson, Jordan; Adler-Milstein, Julia


    To assess whether the level of health information exchange (HIE) in U.S. hospitals is related to technology capabilities, incentives to exchange, or both. A total of 1,812 hospitals attesting to stage 2 of Medicare's Meaningful Use Incentive Program through April 2016. Hospital-level, multivariate OLS regression with state fixed effects was used to analyze the relationship between technology capability and incentives measures, and percent of care transitions with summary of care records (SCRs) sent electronically to subsequent providers. Stage 2 hospitals reported sending SCRs electronically for an average of 41 percent (median = 33 percent) of transitions. HIE level is related to four capability measures, one incentive measure, and one measure that is related to both capability and incentive. Percent of transitions with SCRs sent electronically was 3 percentage points higher (95 percent CI: 0.1-5.1) for hospitals with a third-party HIE vendor, 3 percentage points higher (95 percent CI: 0.5-5.4) for hospitals with an EHR vendor as their HIE vendor, and 3 percentage points higher (95 percent CI: 0.4-5.4) for hospitals that automatically alert primary care providers. The direction and statistical significance of the relationships between specific EHR vendor and electronic SCR transmission level varied by vendor. Nonprofits and government hospitals performed 5 percentage points higher (95 percent CI: 1.5-9.1) and 8 percentage points higher (95 percent CI: 3.4-12.3) than for-profits. Hospitals in systems performed 3 percentage points higher (95 percent CI: 0.8-6.1). The overall level of HIE is low, with hospitals sending an SCR electronically for less than half of patient transitions. Specific hospital characteristics related to both technology capabilities and incentives were associated with higher levels of HIE. © Health Research and Educational Trust.

  13. The origins of enhanced activity in factor VIIa analogs and the interplay between key allosteric sites revealed by hydrogen exchange mass spectrometry

    DEFF Research Database (Denmark)

    Rand, Kasper D; Andersen, Mette D; Olsen, Ole H


    Factor VIIa (FVIIa) circulates in the blood in a zymogen-like state. Only upon association with membrane-bound tissue factor (TF) at the site of vascular injury does FVIIa become active and able to initiate blood coagulation. Here we used hydrogen exchange monitored by mass spectrometry to invest......Factor VIIa (FVIIa) circulates in the blood in a zymogen-like state. Only upon association with membrane-bound tissue factor (TF) at the site of vascular injury does FVIIa become active and able to initiate blood coagulation. Here we used hydrogen exchange monitored by mass spectrometry...

  14. Mediated effects of physical risk factors, leader-member exchange and empowerment in predicting perceived injury risk. (United States)

    Muldoon, Jeffery; Matthews, Russell A; Foley, Caroline


    In the context of conservation of resources theory, we examine the indirect (mediated) effects of physical risk factors, leader-member exchange (LMX) and empowerment on perceived injury risk in a heterogeneous sample (N = 226) of individuals employed in occupations related to production, construction and installation/maintenance. Positioning work role stressors and upward safety communications as two important mediating variables, as predicted, LMX and empowerment demonstrated significant indirect effects on perceived injury risk. Results from our model also provide preliminary evidence that an asymmetrical dualistic process exists in terms of the effect physical risk factors have on perceived injury risk via depletion of both psychological (i.e. role stressors) and physical resources (i.e. physical symptoms). Theoretical and practical implications based on the results of our model are also discussed. Copyright © 2011 John Wiley & Sons, Ltd.


    Directory of Open Access Journals (Sweden)

    E. Batara Manurung


    Full Text Available The purpose of this study is to examine the effect of capital structure (debt to asset ratio and debt to equity ratio, economic value added, and coal reserves towards Tobin’s Q, as a proxy of firms’ value, of coal companies listed on the Indonesia Stock Exchange (IDX. This study also aims to examine the contribution of Tobin’s Q towards sectoral stock index price of coal production companies. From a total population of 23 companies, this study took a sample of 16 coal production companies using purposive sampling method. The data used is collected from the companies audited financial statements and annual reports in IDX’s website from 2009 to 2014. The results of multiple linear regression analysis show that there is significant impact of economic value added, coal reserves and profitability dummy towards Tobin’s Q. Furthermore, the results of linear regression analysis show that there is significant impact of Tobin’s Q towards sectoral stock index price of coal production companies. Based on the results of this study, the financial decision makers in coal production companies are advised to use economic value added, availability of coal reserves and profitability in improving firm value reflected in its share price.Keywords: capital structure, coal reserves, economic value added, Tobin’s Q

  16. Human factors issues in aircraft maintenance and inspection : "information exchange and communications". (United States)


    The Federal Aviation Administration sponsored a 2-day meeting in December 1989 as part of a continuing program to address issues of human factors and personnel performance in aviation maintenance and inspection. This meeting focused on issues of "inf...

  17. Opposing HDAC4 nuclear fluxes due to phosphorylation by β-adrenergic activated protein kinase A or by activity or Epac activated CaMKII in skeletal muscle fibres (United States)

    Liu, Yewei; Schneider, Martin F


    Class IIa histone deacetylases (HDACs) move between skeletal muscle fibre cytoplasm and nuclei in response to various stimuli, suppressing activity of the exclusively nuclear transcription factor Mef2. Protein kinase A (PKA) phosphorylates class IIa HDACs in cardiac muscle, resulting in HDAC nuclear accumulation, but this has not been examined in skeletal muscle. Using HDAC4–green fluorescent protein (HDAC4-GFP) expressed in isolated skeletal muscle fibres, we now show that activation of PKA by the beta-receptor agonist isoproterenol or dibutyryl (Db) cAMP causes a steady HDAC4-GFP nuclear influx. The beta-receptor blocker propranolol or PKA inhibitor Rp-cAMPS blocks the effects of isoproterenol on the nuclear influx of HDAC4-GFP, and Rp-cAMPS blocks the effects of Db cAMP. The HDAC4-GFP construct having serines 265 and 266 replaced with alanines, HDAC4 (S265/266A)-GFP, did not respond to beta-receptor or PKA activation. Immunoprecipitation results show that HDAC4-GFP is a substrate of PKA, but HDAC4 (S265/266A)-GFP is not, implicating HDAC4 serines 265/266 as the site(s) phosphorylated by PKA. During 10 Hz trains of muscle fibre electrical stimulation, the nuclear efflux rate of HDAC4-GFP, but not of HDAC4 (S265/266)-GFP, was decreased by PKA activation, directly demonstrating antagonism between the effects of fibre stimulation and beta-adrenergic activation of PKA on HDAC4 nuclear fluxes. 8-CPT, a specific activator of Epac, caused nuclear efflux of HDAC4-GFP, opposite to the effect of PKA. Db cAMP increased both phosphorylated PKA and GTP-bound Rap1. Our results demonstrate that the PKA and CaMKII pathways play important opposing roles in skeletal muscle gene expression by oppositely affecting the subcellular localization of HDAC4. PMID:23652597

  18. Proton Form Factor Puzzle and the CEBAF Large Acceptance Spectrometer (CLAS) Two-Photon Exchange Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Rimal, Dipak [Florida Intl Univ., Miami, FL (United States)


    The electromagnetic form factors are the most fundamental observables that encode information about the internal structure of the nucleon. This dissertation explored dependence of R on kinematic variables such as squared four-momentum transfer (Q2) and the virtual photon polarization parameter (ε).

  19. Carbon exchange between ecosystems and atmosphere in the Czech Republic is affected by climate factors

    Energy Technology Data Exchange (ETDEWEB)

    Marek, Michal V., E-mail: [Global Change Research Centres, Academy of Science of the Czech Republic, Belidla 4a CZ-60300 Brno (Czech Republic); Institute of Forest Ecology Forestry Faculty, Mendel University Brno, Zemedelska 3, CZ-614 00 (Czech Republic); Janous, Dalibor; Taufarova, Klara; Havrankova, Katerina; Pavelka, Marian; Kaplan, Veroslav [Global Change Research Centres, Academy of Science of the Czech Republic, Belidla 4a CZ-60300 Brno (Czech Republic); Markova, Irena [Institute of Forest Ecology Forestry Faculty, Mendel University Brno, Zemedelska 3, CZ-614 00 (Czech Republic)


    By comparing five ecosystem types in the Czech Republic over several years, we recorded the highest carbon sequestration potential in an evergreen Norway spruce forest (100%) and an agroecosystem (65%), followed by European beech forest (25%) and a wetland ecosystem (20%). Because of a massive ecosystem respiration, the final carbon gain of the grassland was negative. Climate was shown to be an important factor of carbon uptake by ecosystems: by varying the growing season length (a 22-d longer season in 2005 than in 2007 increased carbon sink by 13%) or by the effect of short- term synoptic situations (e.g. summer hot and dry days reduced net carbon storage by 58% relative to hot and wet days). Carbon uptake is strongly affected by the ontogeny and a production strategy which is demonstrated by the comparison of seasonal course of carbon uptake between coniferous (Norway spruce) and deciduous (European beech) stands. - Highlights: > Highest carbon sequestration potential in evergreen Norway spruce forest (100%) and an agroecosystem (65%), followed by European beech forest (25%) and a wetland ecosystem (20%). > The final carbon gain of the grassland was negative (massive ecosystem respiration). > Climate is important factor of net primary productivity. > Carbon uptake is strongly affected by the ontogeny and a production strategy of ecosystem. - Identification of the apparent differences in the carbon storage by different ecosystem types.

  20. Factors Related to Initiating Interpersonal Contacts on Internet Dating Sites: A View From the Social Exchange Theory

    Directory of Open Access Journals (Sweden)

    Rivka Shtatfeld


    Full Text Available The purpose of this study was to identify factors that influence dating-site users to initiate contact with potential romantic partners. The study was carried out by observing online behaviors and analyzing the profiles and authentic messages of these users (N = 106 over seven months. Contacts made by and with the research participants were analyzed in terms of the relationships between initiators‘ and receivers‘ demographic variables (marital status, age, level of education, income, writing skills, and stated physical appearance. In addition, the relationship between contacting partners and site accessibility was examined. The findings revealed that dating-site users initiated contact primarily with those having a similar marital status or slightly better characteristics (income, education, writing skills. In regard to writing skills, it was found that skilled writers attracted more contacts than did less skilled writers. However, the factor that was found to be most significantly related to initiating contact was the length of time that elapsed from last connection to the site, which implies the perceived accessibility of potential romantic partners. The findings were explained in terms of the Social Exchange Theory: people are attracted to those who grant them rewards.

  1. Particle-vibration coupling and exchange-current effects on the magnetic electron-scattering form factor

    Energy Technology Data Exchange (ETDEWEB)

    Krewald, S.; Lallena, A.M.; Dehesa, J.S.


    Inelastic electron-scattering form factors of magnetic states in closed-shell nuclei are calculated taking into account the combined effect of the mesonic degrees of freedom and the two-particle-two-hole components of the nuclear wave functions which come from the particle-core vibration coupling. The one-body nucleon- and two-body meson-exchange current contribution to the form factor are evaluated with the same realistic mean field. Application to various high-spin magnetic states of oxygen and lead is made. The comparison with experiment shows an excellent agreement for the states 14/sup -/(6.74 MeV) and 12/sup -/sub(t)(7.06 MeV) in lead, while such is not the case for the second 12/sup -//sub 2/(6.43 MeV) state in lead and the 4/sup -/(18.98 MeV) state in oxygen essentially due to mixing configuration effects and the non-consideration of 3p3h excitations, respectively. (orig.).

  2. Chaos and order in stateless societies: Intercommunity exchange as a factor impacting the population dynamical patterns

    Energy Technology Data Exchange (ETDEWEB)

    Medvinsky, Alexander B., E-mail: [Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino 142290, Moscow Region (Russian Federation); Rusakov, Alexey V. [Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino 142290, Moscow Region (Russian Federation)


    Highlights: > We model community dynamics in stateless societies. > Intercommunity barter is shown to be a factor impacting the societies dynamics. > Increase in the human population growth rate can lead to appearance of chaos. > Secular and millennial cycles are found to arise as a result of the barter. - Abstract: The once abstract notions of dynamical chaos now appear naturally in various systems [Kaplan D, Glass L. Understanding nonlinear dynamics. New York: Springer; 1995]. As a result, future trajectories of the systems may be difficult to predict. In this paper, we demonstrate the appearance of chaotic dynamics in model human communities, which consist of producers of agricultural product and producers of agricultural equipment. In the case of a solitary community, the horizon of predictability of the human population dynamics is shown to be dependent on both intrinsic instability of the dynamics and the chaotic attractor sizes. Since a separate community is usually a part of a larger commonality, we study the dynamics of social systems consisting of two interacting communities. We show that intercommunity barter can lead to stabilization of the dynamics in one of the communities, which implies persistence of stable equilibrium under changes of the maximum value of the human population growth rate. However, in the neighboring community, the equilibrium turns into a stable limit cycle as the maximum value of the human population growth rate increases. Following an increase in the maximum value of the human population growth rate leads to period-doubling bifurcations resulting in chaotic dynamics. The horizon of predictability of the chaotic oscillations is found to be limited by 5 years. We demonstrate that the intercommunity interaction can lead to the appearance of long-period harmonics in the chaotic time series. The period of the harmonics is of order 100 and 1000 years. Hence the long-period changes in the population size may be considered as an

  3. A General Econometric Model of the Determinants of Library Subscription Prices of Scholarly Journals: The Role of Exchange Rate Risk and Other Factors. (United States)

    Chressanthis, George A.; Chressanthis, June D.


    Provides regression-based empirical evidence of the effects of variations in exchange rate risk on 1985 library prices of the top-ranked 99 journals in economics. The relationship between individual journal prices and library prices is shown, and other factors associated with increases and decreases in library journal prices are given. (Contains…

  4. Characterization of Stress-Exposed Granulocyte Colony Stimulating Factor Using ELISA and Hydrogen/Deuterium Exchange Mass Spectrometry (United States)

    Tsuchida, Daisuke; Yamazaki, Katsuyoshi; Akashi, Satoko


    Information on the higher-order structure is important in the development of biopharmaceutical drugs. Recently, hydrogen/deuterium exchange coupled with mass spectrometry (HDX-MS) has been widely used as a tool to evaluate protein conformation, and unique automated systems for HDX-MS are now commercially available. To investigate the potential of this technique for the prediction of the activity of biopharmaceuticals, granulocyte colony stimulating factor (G-CSF), which had been subjected to three different stress types, was analyzed using HDX-MS and through comparison with receptor-binding activity. It was found that HDX-MS, in combination with ion mobility separation, was able to identify conformational changes in G-CSF induced by stress, and a good correlation with the receptor-binding activity was demonstrated, which cannot be completely determined by conventional peptide mapping alone. The direct evaluation of biological activity using bioassay is absolutely imperative in biopharmaceutical development, but HDX-MS can provide the alternative information in a short time on the extent and location of the structural damage caused by stresses. Furthermore, the present study suggests the possibility of this system being a versatile evaluation method for the preservation stability of biopharmaceuticals.

  5. RINL, guanine nucleotide exchange factor Rab5-subfamily, is involved in the EphA8-degradation pathway with odin.

    Directory of Open Access Journals (Sweden)

    Hiroaki Kajiho

    Full Text Available The Rab family of small guanosine triphosphatases (GTPases plays a vital role in membrane trafficking. Its active GTP-bound state is driven by guanine nucleotide-exchange factors (GEFs. Ras and Rab interactor (or Ras interaction/interference-like (RINL, which contains a conserved VPS9 domain critical for GEF action, was recently identified as a new Rab5 subfamily GEF in vitro. However, its detailed function and interacting molecules have not yet been fully elucidated. Here we found that RINL has GEF activity for the Rab5 subfamily proteins by measuring their GTP-bound forms in cultured cells. We also found that RINL interacts with odin, a member of the ankyrin-repeat and sterile-alpha motif (SAM domain-containing (Anks protein family. In addition, the Eph tyrosine kinase receptor EphA8 formed a ternary complex with both RINL and odin. Interestingly, RINL expression in cultured cells reduced EphA8 levels in a manner dependent on both its GEF activity and interaction with odin. In addition, knockdown of RINL increased EphA8 level in HeLa cells. Our findings suggest that RINL, as a GEF for Rab5 subfamily, is implicated in the EphA8-degradation pathway via its interaction with odin.

  6. Cdc24, the GDP-GTP exchange factor for Cdc42, is required for invasive hyphal growth of Candida albicans. (United States)

    Bassilana, Martine; Blyth, James; Arkowitz, Robert A


    Candida albicans, the most common human fungal pathogen, is particularly problematic for immunocompromised individuals. The reversible transition of this fungal pathogen to a filamentous form that invades host tissue is important for its virulence. Although different signaling pathways such as a mitogen-activated protein kinase and a protein kinase A cascade are critical for this morphological transition, the function of polarity establishment proteins in this process has not been determined. We examined the role of four different polarity establishment proteins in C. albicans invasive growth and virulence by using strains in which one copy of each gene was deleted and the other copy expressed behind the regulatable promoter MET3. Strikingly, mutants with ectopic expression of either the Rho G-protein Cdc42 or its exchange factor Cdc24 are unable to form invasive hyphal filaments and germ tubes in response to serum or elevated temperature and yet grow normally as a budding yeast. Furthermore, these mutants are avirulent in a mouse model for systemic infection. This function of the Cdc42 GTPase module is not simply a general feature of polarity establishment proteins. Mutants with ectopic expression of the SH3 domain containing protein Bem1 or the Ras-like G-protein Bud1 can grow in an invasive fashion and are virulent in mice, albeit with reduced efficiency. These results indicate that a specific regulation of Cdc24/Cdc42 activity is required for invasive hyphal growth and suggest that these proteins are required for pathogenicity of C. albicans.

  7. Driving factors of interactions between the exchange rate market and the commodity market: A wavelet-based complex network perspective (United States)

    Wen, Shaobo; An, Haizhong; Chen, Zhihua; Liu, Xueyong


    In traditional econometrics, a time series must be in a stationary sequence. However, it usually shows time-varying fluctuations, and it remains a challenge to execute a multiscale analysis of the data and discover the topological characteristics of conduction in different scales. Wavelet analysis and complex networks in physical statistics have special advantages in solving these problems. We select the exchange rate variable from the Chinese market and the commodity price index variable from the world market as the time series of our study. We explore the driving factors behind the behavior of the two markets and their topological characteristics in three steps. First, we use the Kalman filter to find the optimal estimation of the relationship between the two markets. Second, wavelet analysis is used to extract the scales of the relationship that are driven by different frequency wavelets. Meanwhile, we search for the actual economic variables corresponding to different frequency wavelets. Finally, a complex network is used to search for the transfer characteristics of the combination of states driven by different frequency wavelets. The results show that statistical physics have a unique advantage over traditional econometrics. The Chinese market has time-varying impacts on the world market: it has greater influence when the world economy is stable and less influence in times of turmoil. The process of forming the state combination is random. Transitions between state combinations have a clustering feature. Based on these characteristics, we can effectively reduce the information burden on investors and correctly respond to the government's policy mix.

  8. Simplified in vitro refolding and purification of recombinant human granulocyte colony stimulating factor using protein folding cation exchange chromatography. (United States)

    Vemula, Sandeep; Dedaniya, Akshay; Thunuguntla, Rahul; Mallu, Maheswara Reddy; Parupudi, Pavani; Ronda, Srinivasa Reddy


    Protein folding-strong cation exchange chromatography (PF-SCX) has been employed for efficient refolding with simultaneous purification of recombinant human granulocyte colony stimulating factor (rhG-CSF). To acquire a soluble form of renatured and purified rhG-CSF, various chromatographic conditions, including the mobile phase composition and pH was evaluated. Additionally, the effects of additives such as urea, amino acids, polyols, sugars, oxidizing agents and their amalgamations were also investigated. Under the optimal conditions, rhG-CSF was efficaciously solubilized, refolded and simultaneously purified by SCX in a single step. The experimental results using ribose (2.0M) and arginine (0.6M) combination were found to be satisfactory with mass yield, purity and specific activity of 71%, ≥99% and 2.6×10(8)IU/mg respectively. Through this investigation, we concluded that the SCX refolding method was more efficient than conventional methods which has immense potential for the large-scale production of purified rhG-CSF. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Impact factors on the long-term sustainability of Borehole Heat Exchanger coupled Ground Source Heat Pump System (United States)

    Shao, Haibing; Hein, Philipp; Görke, Uwe-Jens; Bucher, Anke; Kolditz, Olaf


    In recent years, Ground Source Heat Pump System (GSHPS) has been recognized as an efficient technology to utilize shallow geothermal energy. Along with its wide application, some GSHPS are experiencing a gradual decrease in Borehole Heat Exchanger (BHE) outflow temperatures and thus have to be turned off after couple of years' operation. A comprehensive numerical investigation was then performed to model the flow and heat transport processes in and around the BHE, together with the dynamic change of heat pump efficiency. The model parameters were based on the soil temperature and surface weather condition in the Leipzig area. Different scenarios were modelled for a service life of 30 years, to reveal the evolution of BHE outflow and surrounding soil temperatures. It is found that lateral groundwater flow and using BHE for cooling will be beneficial to the energy recovery, along with the efficiency improvement of the heat pump. In comparison to other factors, the soil heat capacity and thermal conductivity are considered to have minor impact on the long-term sustainability of the system. Furthermore, the application of thermally enhanced grout material will improve the sustainability and efficiency. In contrast, it is very likely that undersized systems and improper grouting are the causes of strong system degradation.

  10. Identification and weighting factors influencing the establishment of a single minute exchange of dies in plastic injection industry using VIKOR and Shannon Entropy

    Directory of Open Access Journals (Sweden)

    Gholam Reza Hashemzadeh


    Full Text Available Single minute exchange of dies (SMED is one of the most important tools to achieve lean production system. The main idea of this system is to provide methods and to use creative and innovative solutions for continuous improvement. Due to the importance of this issue and its effect on reducing waste during the production process, this study presents a method to identify and to weight factors in the establishment of a single minute exchange of dies in 14 plastic injection factories. In this study, fourteen factories in injection industry were chosen and the factors influencing the implementation of single minute exchange of dies were identified. Following data collection, decision matrix was formed and the weight of each factor was determined by using Shannon Entropy. Then, in order to determine the readiness of factories, VIKOR method was used to rank companies. The results indicate priorities of the following factors in establishing SMED that include: Senior management support, technical capabilities, technical knowledge of staff and consultants, knowledge of mold design, manufacturing infrastructure, team work, combination of the project team work, benchmarking, training, clear understanding of project objectives, rewards and motivation, proper management expectation, project management, teamwork and organizational culture. Practical implications: Due to the factors, Top manager can make the best decision for implementing of SMED technique. This study develops factors influencing on SMED implementation based on Shannon and VIKOR methods for ranking parameters and plants.

  11. Exchange Protein Directly Activated by cAMP (epac) : A Multidomain cAMP Mediator in the Regulation of Diverse Biological Functions

    NARCIS (Netherlands)

    Schmidt, Martina; Dekker, Frank J.; Maarsingh, Harm

    Since the discovery nearly 60 years ago, cAMP is envisioned as one of the most universal and versatile second messengers. The tremendous feature of cAMP to tightly control highly diverse physiologic processes, including calcium homeostasis, metabolism, secretion, muscle contraction, cell fate, and

  12. Mapping temperature-induced conformational changes in the Escherichia coli heat shock transcription factor sigma 32 by amide hydrogen exchange

    DEFF Research Database (Denmark)

    Rist, Wolfgang; Jørgensen, Thomas J D; Roepstorff, Peter


    gene transcription. To investigate possible heat-induced conformational changes in sigma 32 we performed amide hydrogen (H/D) exchange experiments under optimal growth and heat shock conditions combined with mass spectrometry. We found a rapid exchange of around 220 of the 294 amide hydrogens at 37...... degrees C, indicating that sigma 32 adopts a highly flexible structure. At 42 degrees C we observed a slow correlated exchange of 30 additional amide hydrogens and localized it to a helix-loop-helix motif within domain sigma 2 that is responsible for the recognition of the -10 region in heat shock...

  13. The pulsations of boundary conditions – factor of the rapid wear on heat exchange surfaces in heterogeneous dispersed flows (United States)

    Khodunkov, V. P.


    The results of experimental studies of industrial furnace with a fluidized bed reactor. The data on the values of the coefficient of heat transfer, the quality of fluidization and mixing efficiency. In theory shows that there are significant variables of temperature gradients on the walls of the heat exchange elements are qualitative arguments about the causes of increased wear of heat exchange surfaces in a fluidized bed.

  14. Regulation of Ras exchange factors and cellular localization of Ras activation by lipid messengers in T cells

    Directory of Open Access Journals (Sweden)

    Jesse E. Jun


    Full Text Available The Ras-MAPK signaling pathway is highly conserved throughout evolution and is activated downstream of a wide range of receptor stimuli. Ras guanine nucleotide exchange factors (RasGEFs catalyze GTP loading of Ras and play a pivotal role in regulating receptor-ligand induced Ras activity. In T cells, three families of functionally important RasGEFs are expressed: RasGRF, RasGRP, and SOS-family GEFs.Early on it was recognized that Ras activation is critical for T cell development and that the RasGEFs play an important role herein. More recent work has revealed that nuances in Ras activation appear to significantly impact T cell development and selection. These nuances include distinct biochemical patterns of analog versus digital Ras activation, differences in cellular localization of Ras activation, and intricate interplays between the RasGEFs during distinct T cell developmental stages as revealed by various new mouse models. In many instances, the exact nature of these nuances in Ras activation or how these may result from fine-tuning of the RasGEFs is not understood.One large group of biomolecules critically involved in the control of Ras-GEFs´functions are lipid second messengers. Multiple, yet distinct lipid products are generated following T cell receptor (TCR stimulation and bind to different domains in the RasGRP and SOS RasGEFs to facilitate the activation of the membrane-anchored Ras GTPases. In this review we highlight how different lipid-based elements are generated by various enzymes downstream of the TCR and other receptors and how these dynamic and interrelated lipid products may fine-tune Ras activation by RasGEFs in developing T cells.

  15. The putative guanine nucleotide exchange factor RicA mediates upstream signaling for growth and development in Aspergillus. (United States)

    Kwon, Nak-Jung; Park, Hee-Soo; Jung, Seunho; Kim, Sun Chang; Yu, Jae-Hyuk


    Heterotrimeric G proteins (G proteins) govern growth, development, and secondary metabolism in various fungi. Here, we characterized ricA, which encodes a putative GDP/GTP exchange factor for G proteins in the model fungus Aspergillus nidulans and the opportunistic human pathogen Aspergillus fumigatus. In both species, ricA mRNA accumulates during vegetative growth and early developmental phases, but it is not present in spores. The deletion of ricA results in severely impaired colony growth and the total (for A. nidulans) or near (for A. fumigatus) absence of asexual sporulation (conidiation). The overexpression (OE) of the A. fumigatus ricA gene (AfricA) restores growth and conidiation in the ΔAnricA mutant to some extent, indicating partial conservation of RicA function in Aspergillus. A series of double mutant analyses revealed that the removal of RgsA (an RGS protein of the GanB Gα subunit), but not sfgA, flbA, rgsB, or rgsC, restored vegetative growth and conidiation in ΔAnricA. Furthermore, we found that RicA can physically interact with GanB in yeast and in vitro. Moreover, the presence of two copies or OE of pkaA suppresses the profound defects caused by ΔAnricA, indicating that RicA-mediated growth and developmental signaling is primarily through GanB and PkaA in A. nidulans. Despite the lack of conidiation, brlA and vosA mRNAs accumulated to normal levels in the ΔricA mutant. In addition, mutants overexpressing fluG or brlA (OEfluG or OEbrlA) failed to restore development in the ΔAnricA mutant. These findings suggest that the commencement of asexual development requires unknown RicA-mediated signaling input in A. nidulans.

  16. Activation of Rac1 by the guanine nucleotide exchange factor Dck1 is required for invasive filamentous growth in the pathogen Candida albicans. (United States)

    Hope, Hannah; Bogliolo, Stéphanie; Arkowitz, Robert A; Bassilana, Martine


    Rho G proteins and their regulators are critical for cytoskeleton organization and cell morphology in all eukaryotes. In the opportunistic pathogen Candida albicans, the Rho G proteins Cdc42 and Rac1 are required for the switch from budding to filamentous growth in response to different stimuli. We show that Dck1, a protein with homology to the Ced-5, Dock180, myoblast city family of guanine nucleotide exchange factors, is necessary for filamentous growth in solid media, similar to Rac1. Our results indicate that Dck1 and Rac1 do not function in the same pathway as the transcription factor Czf1, which is also required for embedded filamentous growth. The conserved catalytic region of Dck1 is required for such filamentous growth, and in vitro this region directly binds a Rac1 mutant, which mimics the nucleotide-free state. In vivo overexpression of a constitutively active Rac1 mutant, but not wild-type Rac1, in a dck1 deletion mutant restores filamentous growth. These results indicate that the Dock180 guanine nucleotide exchange factor homologue, Dck1 activates Rac1 during invasive filamentous growth. We conclude that specific exchange factors, together with the G proteins they activate, are required for morphological changes in response to different stimuli.

  17. Barter exchanges

    DEFF Research Database (Denmark)

    Sudzina, Frantisek

    Although barter is often perceived as something that proceeded money, barter is still used. The focus of the paper is on barter exchanges. Barter exchanges are used both in developing countries as well as in developed countries (including the U.S.). They are used by both organizations...... and individuals. They usually allow to exchange good but some include also services. Some exchanges allow only for bi-directional barter, i.e. when only two parties are involved in the exchange. But probably most of the barter exchanges use barter money; this makes it easier to exchange goods and services...

  18. Activation of exchange protein activated by cAMP in the rat basolateral amygdala impairs reconsolidation of a memory associated with self-administered cocaine.

    Directory of Open Access Journals (Sweden)

    Xun Wan

    Full Text Available The intracellular mechanisms underlying memory reconsolidation critically involve cAMP signaling. These events were originally attributed to PKA activation by cAMP, but the identification of Exchange Protein Activated by cAMP (Epac, as a distinct mediator of cAMP signaling, suggests that cAMP-regulated processes that subserve memory reconsolidation are more complex. Here we investigated how activation of Epac with 8-pCPT-cAMP (8-CPT impacts reconsolidation of a memory that had been associated with cocaine self-administration. Rats were trained to lever press for cocaine on an FR-1 schedule, in which each cocaine delivery was paired with a tone+light cue. Lever pressing was then extinguished in the absence of cue presentations and cocaine delivery. Following the last day of extinction, rats were put in a novel context, in which the conditioned cue was presented to reactivate the cocaine-associated memory. Immediate bilateral infusions of 8-CPT into the basolateral amygdala (BLA following reactivation disrupted subsequent cue-induced reinstatement in a dose-dependent manner, and modestly reduced responding for conditioned reinforcement. When 8-CPT infusions were delayed for 3 hours after the cue reactivation session or were given after a cue extinction session, no effect on cue-induced reinstatement was observed. Co-administration of 8-CPT and the PKA activator 6-Bnz-cAMP (10 nmol/side rescued memory reconsolidation while 6-Bnz alone had no effect, suggesting an antagonizing interaction between the two cAMP signaling substrates. Taken together, these studies suggest that activation of Epac represents a parallel cAMP-dependent pathway that can inhibit reconsolidation of cocaine-cue memories and reduce the ability of the cue to produce reinstatement of cocaine-seeking behavior.

  19. Clinical outcomes and predictive factors related to good outcomes in plasma exchange in severe attack of NMOSD and long extensive transverse myelitis: Case series and review of the literature. (United States)

    Aungsumart, Saharat; Apiwattanakul, Metha


    To investigate the predictive factors associated with good outcomes of plasma exchange in severe attacks through neuromyelitis optica spectrum disorder (NMOSD) and long extensive transverse myelitis (LETM). In addition, to review the literature of predictive factors associated with the good outcomes of plasma exchange in central nervous system inflammatory demyelinating diseases (CNS IDDs). Retrospective study in 27 episodes of severe acute attacks myelitis and optic neuritis in 24 patients, including 20 patients with NMOSD seropositive, 1 patient with NMOSD seronegative and 3 patients with LETM. Plasma exchange was performed, reflecting poor responses to high-dose intravenous methylprednisolone (IVMP) therapy. The outcomes of the present study were the functional outcome improvements at 6 months after plasma exchange. The predictive factors of good outcomes after plasma exchange were determined in this cohort, and additional factors reported in the literature were reviewed. Plasma exchange was performed in 16 spinal cord attacks and 11 attacks of optic neuritis. Twenty patients were female (83%). The median age of the patients at the time of plasma exchange was 41 years old. The median disease duration was 0.6 years. The AQP4-IgG status was positive in 20 patients (83%). Plasma exchange following IVMP therapy led to a significant improvement in 81% of the cases after 6 months of follow up. A baseline Expanded Disability Status Scale (EDSS) score ≤6 before the attack was associated with significant improvement at 6 months (p=0.02, OR 58.33, 95%CI 1.92-1770). In addition, we reviewed the evidence for factors associated with good outcomes of plasma exchange in CNS IDDs, classified according to pre-plasma exchange, post-plasma exchange, and radiological features. Plasma exchange following IVMP therapy is effective as a treatment for patients experiencing a severe attack of NMOSD or LETM. The factors associated with good outcomes after plasma exchange in CNS IDDs are

  20. Canopy gas exchange and water use efficiency of 'Empire' apple in response to particle film, irrigation, and microclimatic factors (United States)

    This study examined the interaction between a reflective particle film and water use efficiency (WUE) response of irrigated and non-irrigated apple trees over a wide range of environmental conditions. The objectives were to measure the specific gas exchange and WUE response of 'Empire' apple treate...

  1. The X-Factor: On the Relevance of Implicit Leadership and Followership Theories for Leader-Member Exchange (LMX) Agreement

    NARCIS (Netherlands)

    S. van Gils (Suzanne); N. van Quaquebeke (Niels); D.L. van Knippenberg (Daan)


    textabstractWhile Leader-Member Exchange (LMX) research shows that leaders engage in different kinds of relationships with different followers, it remains somewhat of an enigma why one and the same relationship is often rated differently by a leader and the respective follower. We seek to fill that

  2. The X-Factor: On the Relevance of Implicit Leadership and Followership Theories for Leader-Member Exchange (LMX) Agreement


    Gils, Suzanne; Quaquebeke, Niels; Knippenberg, Daan


    textabstractWhile Leader-Member Exchange (LMX) research shows that leaders engage in different kinds of relationships with different followers, it remains somewhat of an enigma why one and the same relationship is often rated differently by a leader and the respective follower. We seek to fill that conceptual void by explaining when and why such LMX disagreement is likely to occur. To do so, we reconsider antecedents of LMX quality perceptions and outline how each party’s LMX quality percepti...

  3. Factors influencing the separation of oligonucleotides using reversed-phase/ion-exchange mixed-mode high performance liquid chromatography columns. (United States)

    Biba, Mirlinda; Jiang, Eileen; Mao, Bing; Zewge, Daniel; Foley, Joe P; Welch, Christopher J


    New mixed-mode columns consisting of reversed-phase and ion-exchange separation modes were evaluated for the analysis of short RNA oligonucleotides (∼20mers). Conventional analysis for these samples typically involves using two complementary methods: strong anion-exchange liquid chromatography (SAX-LC) for separation based on charge, and ion-pair reversed-phase liquid chromatography (IP-RPLC) for separation based on hydrophobicity. Recently introduced mixed-mode high performance liquid chromatography (HPLC) columns combine both reversed-phase and ion-exchange modes, potentially offering a simpler analysis by combining the benefits of both separation modes into a single method. Analysis of a variety of RNA oligonucleotide samples using three different mixed-mode stationary phases showed some distinct benefits for oligonucleotide separation and analysis. When using these mixed-mode columns with typical IP-RPLC mobile phase conditions, such as ammonium acetate or triethylammonium acetate as the primary ion-pair reagent, the separation was mainly based on the IP-RPLC mode. However, when changing the mobile phase conditions to those more typical for SAX-LC, such as salt gradients with NaCl or NaBr, very different separation patterns were observed due to mixed-mode interactions. In addition, the Scherzo SW-C18 and SM-C18 columns with sodium chloride or sodium bromide salt gradients also showed significant improvements in peak shape. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Neighborhood History as a Factor Shaping Syringe Distribution Networks Among Drug Users at a U.S. Syringe Exchange. (United States)

    Braine, Naomi; Acker, Caroline; Goldblatt, Cullen; Yi, Huso; Friedman, Samuel; Desjarlais, Don C


    Throughout the US, high-visibility drug markets are concentrated in neighborhoods with few economic opportunities, while drug buyers/users are widely dispersed. A study of Pittsburgh Syringe Exchange participants provides data on travel between and network linkages across neighborhoods with different levels of drug activity. There are distinct racial patterns to syringe distribution activity within networks and across neighborhoods. Pittsburgh's history suggests these patterns emerge from historical patterns of social and economic development. Study data demonstrate the ability of IDUs to form long term social ties across racial and geographic boundaries and use them to reduce the risk of HIV transmission.

  5. The guanine exchange factor Gartenzwerg and the small GTPase Arl1 function in the same pathway with Arfaptin during synapse growth

    Directory of Open Access Journals (Sweden)

    Leo Chang


    Full Text Available The generation of neuronal morphology requires transport vesicles originating from the Golgi apparatus (GA to deliver specialized components to the axon and dendrites. Drosophila Arfaptin is a membrane-binding protein localized to the GA that is required for the growth of the presynaptic nerve terminal. Here we provide biochemical, cellular and genetic evidence that the small GTPase Arl1 and the guanine-nucleotide exchange factor (GEF Gartenzwerg are required for Arfaptin function at the Golgi during synapse growth. Our data define a new signaling pathway composed of Arfaptin, Arl1, and Garz, required for the generation of normal synapse morphology.

  6. Fourth-generation epac-based FRET sensors for cAMP feature exceptional brightness, photostability and dynamic range: characterization of dedicated sensors for FLIM, for ratiometry and with high affinity.

    Directory of Open Access Journals (Sweden)

    Jeffrey Klarenbeek

    Full Text Available Epac-based FRET sensors have been widely used for the detection of cAMP concentrations in living cells. Originally developed by us as well as others, we have since then reported several important optimizations that make these sensors favourite among many cell biologists. We here report cloning and characterization of our fourth generation of cAMP sensors, which feature outstanding photostability, dynamic range and signal-to-noise ratio. The design is based on mTurquoise2, currently the brightest and most bleaching-resistant donor, and a new acceptor cassette that consists of a tandem of two cp173Venus fluorophores. We also report variants with a single point mutation, Q270E, in the Epac moiety, which decreases the dissociation constant of cAMP from 9.5 to 4 μM, and thus increases the affinity ~ 2.5-fold. Finally, we also prepared and characterized dedicated variants with non-emitting (dark acceptors for single-wavelength FLIM acquisition that display an exceptional near-doubling of fluorescence lifetime upon saturation of cAMP levels. We believe this generation of cAMP outperforms all other sensors and therefore recommend these sensors for all future studies.

  7. Factors Affecting the Return Stock Company in Indonesia Stock Exchange (IDX LQ45 in Years 2012-2015

    Directory of Open Access Journals (Sweden)

    Fangki A. Sorongan


    Full Text Available This research aimed to determine the effect of partially and jointly independent variable of Debt to Equity Ratio (DER, Return on Equity (ROA, Return on Equity (ROE, and Net Profit Margin (NPM against the dependent variable on the stock return. Objects of this research were companies listed on the Indonesia Stock Exchange (BEI LQ45 continuously for four years in the period 2012-2015. Companies that qualify for this research were 28 companies. Based on this research, the conclusions indicate that all four independent variables; Debt to Equity Ratio (DER, Return on Equity (ROA, Return on Equity (ROE, and Net Profit Margin (NPM, either jointly or partially give the significant effect on return stock.

  8. 3D-CFD simulation and neural network model for the j and f factors of the wavy fin-and-flat tube heat exchangers

    Directory of Open Access Journals (Sweden)

    M Khoshvaght Aliabadi


    Full Text Available A three dimensional (3D computational fluid dynamics (CFD simulation and a neural network model are presented to estimate the behaviors of the Colburn factor (j and the Fanning friction factor (f for wavy fin - and - flat tube (WFFT heat exchangers. Effects of the five geometrical factors of fin pitch, fin height, fin length, fin thickness, and wavy amplitude are investigated over a wide range of Reynolds number (600factors as a function of Reynolds number. The computational results have an adequate accuracy when compared to experimental data. The accuracy of the calculations of the j and f factors are evaluated by the values of the absolute average relative deviation (AARD, being respectively 3.8% and 8.2% for the CFD simulation and 1.3% and 1% for the neural network model. Finally, new correlations are proposed to estimate the values of the j and f factors with 3.22% and 3.68% AARD respectively.

  9. Exchange of Sex for Drugs or Money in Adolescents and Young Adults: An Examination of Sociodemographic Factors, HIV-Related Risk, and Community Context. (United States)

    Boyer, Cherrie B; Greenberg, Lauren; Chutuape, Kate; Walker, Bendu; Monte, Dina; Kirk, Jennifer; Ellen, Jonathan M


    The goal of this research was to examine associations among sociodemographic factors, HIV risk, and community context (e.g., economic insecurity, job training, housing instability, crime victimization, and perceived community norms) in adolescents and young adults who ever exchanged sex for drugs or money. Anonymous survey data were collected using ACASIs at community venues where adolescents and young adults congregate in resource-challenged, STI prevalent, urban, US neighborhoods. Conventional descriptive statistics, Fisher's exact tests, and generalized estimating equations approaches were used to examine associations. Participants (1818, 95.5 % of those screened eligible) were, on average, aged 21.0 years; 42.2 % were males, and 4.6 % were transgender. Almost one-third (32.1 %) identified as gay or lesbian, 18.1 % identified as bisexual; 66.2 % were Black and 21.0 % were Hispanic; 1.3 % was 'living on the street'. A sizeable proportion reported HIV-related risk: 16.3 % exchanged sex, 12.6 % had sex with someone they knew to be HIV-infected, 7.8 % had sex with someone who injected drugs, and 1.3 % injected drugs. Multivariate comparisons identified a number of variables (e.g., being male or transgender, homelessness, sex with a partner who has HIV, STI history, unemployment, job training access, housing instability, crime victimization, perceived community norms) that were significantly associated with exchange of sex (p development of effective evidence-based prevention strategies.

  10. Growing season length as a key factor of cumulative net ecosystem exchange over the pine forest ecosystems in Europe

    Czech Academy of Sciences Publication Activity Database

    Danielewska, A.; Urbaniak, M.; Olejnik, Janusz


    Roč. 29, č. 2 (2015), s. 129-135 ISSN 0236-8722 Institutional support: RVO:67179843 Keywords : forest * carbon dioxide * eddy covariance * growing season length Subject RIV: EH - Ecology, Behaviour Impact factor: 1.067, year: 2015

  11. One-step refolding and purification of recombinant human tumor necrosis factor-α (rhTNF-α) using ion-exchange chromatography. (United States)

    Wang, Yan; Ren, Wenxuan; Gao, Dong; Wang, Lili; Yang, Ying; Bai, Quan


    Protein refolding is a key step for the production of recombinant proteins, especially at large scales, and usually their yields are very low. Chromatographic-based protein refolding techniques have proven to be superior to conventional dilution refolding methods. High refolding yield can be achieved using these methods compared with dilution refolding of proteins. In this work, recombinant human tumor necrosis factor-α (rhTNF-α) from inclusion bodies expressed in Escherichia coli was renatured with simultaneous purification by ion exchange chromatography with a DEAE Sepharose FF column. Several chromatographic parameters influencing the refolding yield of the denatured/reduced rhTNF-α, such as the urea concentration, pH value and concentration ratio of glutathione/oxidized glutathione in the mobile phase, were investigated in detail. Under optimal conditions, rhTNF-α can be renatured and purified simultaneously within 30 min by one step. Specific bioactivity of 2.18 × 10(8) IU/mg, purity of 95.2% and mass recovery of 76.8% of refolded rhTNF-α were achieved. Compared with the usual dilution method, the ion exchange chromatography method developed here is simple and more effective for rhTNF-α refolding in terms of specific bioactivity and mass recovery. Copyright © 2014 John Wiley & Sons, Ltd.

  12. The auto-inhibitory state of Rho guanine nucleotide exchange factor ARHGEF5/TIM can be relieved by targeting its SH3 domain with rationally designed peptide aptamers. (United States)

    He, Ping; Tan, De-Li; Liu, Hong-Xiang; Lv, Feng-Lin; Wu, Wei


    The short isoform of Rho guanine nucleotide exchange factor ARHGEF5 is known as TIM, which plays diverse roles in, for example, tumorigenesis, neuronal development and Src-induced podosome formation through the activation of its substrates, the Rho family of GTPases. The activation is auto-inhibited by a putative helix N-terminal to the DH domain of TIM, which is stabilized by the intramolecular interaction of C-terminal SH3 domain with a poly-proline sequence between the putative helix and the DH domain. In this study, we systematically investigated the structural basis, energetic landscape and biological implication underlying TIM auto-inhibition by using atomistic molecular dynamics simulations and binding free energy analysis. The computational study revealed that the binding of SH3 domain to poly-proline sequence is the prerequisite for the stabilization of TIM auto-inhibition. Thus, it is suggested that targeting SH3 domain with competitors of the poly-proline sequence would be a promising strategy to relieve the auto-inhibitory state of TIM. In this consideration, we rationally designed a number of peptide aptamers for competitively inhibiting the SH3 domain based on modeled TIM structure and computationally generated data. Peptide binding test and guanine nucleotide exchange analysis solidified that these designed peptides can both bind to the SH3 domain potently and activate TIM-catalyzed RhoA exchange reaction effectively. Interestingly, a positive correlation between the peptide affinity and induced exchange activity was observed. In addition, separate mutation of three conserved residues Pro49, Pro52 and Lys54 - they are required for peptide recognition by SH3 domain -- in a designed peptide to Ala would completely abolish the capability of this peptide activating TIM. All these come together to suggest an intrinsic relationship between peptide binding to SH3 domain and the activation of TIM. Copyright © 2015 Elsevier B.V. and Société Française de

  13. Exchange Network (United States)

    The Environmental Information Exchange Network (EIEN) is an Internet-based system used by state, tribal and territorial partners to securely share environmental and health information with one another and EPA.


    Directory of Open Access Journals (Sweden)



    Full Text Available This paper experimentally investigates the performance and capacity of Purolite C100E commercial resin recommended for water softening applications in the food industry. The practical ion exchange capacity and the softening process efficiency are studied in batch mode as a function of the sorption specific process factors. Optimum operation conditions were determined as initial pH 7.1, resin dose 8 g dry resin•L-1, temperature 25 oC, contact time of 360 min, and in those conditions the retention capacity for the Ca2+ ions is 17.18 mg•g-1 that corresponds to a removal efficiency equal to 85.7%.

  15. [Study of the Sociodemographic Factors and Risky Behaviours Associated with the Acquisition of Sexual Transmitted Infections by Foreign Exchange Students in Portugal]. (United States)

    Gravata, Andreia; Castro, Rita; Borges-Costa, João


    Sexual transmitted infections are a main cause of morbidity, being a public health problem due to its reproductive complications, mostly observed in teenagers and young adults. The purpose of this study was to evaluate sociodemographic factors and risky behaviours associated with sexual transmitted infections acquisition and to assess personal awareness of risky behaviour and the knowledge about Chlamydia trachomatis infection between foreign exchange students in Portugal. The main instrument for data collection was a questionnaire, applied to foreign students in university exchange in Portugal, during the years 2012/2013, 2013/2014 e 2014/2015 Results: Three hundred and thirty eight (338) questionnaires were evaluated, being 58.3% female students, aged between 17 and 30 years old. Mean age for the beginning of the sexual activity was 17.5 years old and the mean number of lifetime sexual partners was 6.9. Concerning the answers given: 11.8% mentioned a sexual relationship with the same gender, 9.5% mentioned that they have never done oral sex and 29% assumed they had practiced anal sex; 82.1% mentioned alcohol/drugs consumption; 21% did not know that Sexual transmitted infections can be transmitted through oral sex and 42.3% did not recognize Chlamydia trachomatis as an Sexual transmitted infections agent. Although sexual transmitted infections can affect individuals of all ages, races and sexual orientation, various demographic, social and behavioral factors have revealed influence in their prevalence rates. Despite knowing about sexual transmitted infections, these students maintain sexual risky behaviours, mainly early age for starting sexual activity, multiple sexual partners and the absence of protection during sexual activities.

  16. Parathyroid hormone inhibition of Na{sup +}/H{sup +} exchanger 3 transcription: Intracellular signaling pathways and transcription factor expression

    Energy Technology Data Exchange (ETDEWEB)

    Neri, Elida Adalgisa; Bezerra, Camila Nogueira Alves, E-mail:; Queiroz-Leite, Gabriella Duarte; Polidoro, Juliano Zequini; Rebouças, Nancy Amaral


    The main transport mechanism of reabsorption of sodium bicarbonate and fluid in the renal proximal tubules involves Na{sup +}/H{sup +} exchanger 3 (NHE3), which is acutely and chronically downregulated by parathyroid hormone (PTH). Although PTH is known to exert an inhibitory effect on NHE3 expression and transcription, the molecular mechanisms involved remain unclear. Here, we demonstrated that, in opossum kidney proximal tubule (OKP) cells, PTH-induced inhibition of Nhe3 gene promoter occurs even in the core promoter that controls expression of the reporter gene. We found that inhibition of the protein kinase A (PKA) and Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathways transformed PTH from an inhibitor of promoter activity into an activator of that same activity, as did point mutations in the EGR1, Sp1, and Sp3 binding consensus elements in the promoter. In nuclear extracts of PTH-treated OKP cells, we also observed increased expression of EGR1 mRNA and of some Sp3 isoforms. Electrophoretic mobility shift assay showed a supershift of the −61 to −42-bp probe with an anti-EGR1 antibody in PTH-treated cells, suggesting that EGR1 binding is relevant for the inhibitory activity of PTH. We conclude that PTH-induced inhibition of NHE3 transcription is related to higher EGR1 expression; to EGR1 binding to the proximal and core promoters; and to PKA and JAK/STAT pathway activation. This mechanism might be responsible, at least in part, for lower NHE3 expression and sodium reabsorption in renal proximal tubules in the presence of high PTH levels. - Highlights: • PTH regulation of Nhe3 promoter depends on EGR1 binding. • EGR1, PKA and JAK/STAT are involved in PTH inhibition of the Nhe3 promoter. • PTH alters expression of EGR1 and Sp3. • PTH inhibits the Nhe3 promoter by regulating PKA and JAK/STAT signaling.

  17. Factors affecting spatial and temporal variability in material exchange between the Southern Everglades wetlands and Florida Bay (USA) (United States)

    Sutula, Martha A.; Perez, Brian C.; Reyes, Enrique; Childers, Daniel L.; Davis, Steve; Day, John W.; Rudnick, David; Sklar, Fred


    Physical and biological processes controlling spatial and temporal variations in material concentration and exchange between the Southern Everglades wetlands and Florida Bay were studied for 2.5 years in three of the five major creek systems draining the watershed. Daily total nitrogen (TN), and total phosphorus (TP) fluxes were measured for 2 years in Taylor River, and ten 10-day intensive studies were conducted in this creek to estimate the seasonal flux of dissolved inorganic nitrogen (N), phosphorus (P), total organic carbon (TOC), and suspended matter. Four 10-day studies were conducted simultaneously in Taylor, McCormick, and Trout Creeks to study the spatial variation in concentration and flux. The annual fluxes of TOC, TN, and TP from the Southern Everglades were estimated from regression equations. The Southern Everglades watershed, a 460-km 2 area that includes Taylor Slough and the area south of the C-111 canal, exported 7.1 g C m -2, 0.46 g N m -2, and 0.007 g P m -2, annually. Everglades P flux is three to four orders of magnitude lower than published flux estimates from wetlands influenced by terrigenous sedimentary inputs. These low P flux values reflect both the inherently low P content of Everglades surface water and the efficiency of Everglades carbonate sediments and biota in conserving and recycling this limiting nutrient. The seasonal variation of freshwater input to the watershed was responsible for major temporal variations in N, P, and C export to Florida Bay; approximately 99% of the export occurred during the rainy season. Wind-driven forcing was most important during the later stages of the dry season when low freshwater head coincided with southerly winds, resulting in a net import of water and materials into the wetlands. We also observed an east to west decrease in TN:TP ratio from 212:1 to 127:1. Major spatial gradients in N:P ratios and nutrient concentration and flux among the creek were consistent with the westward decrease in

  18. Nitrous oxide exchanges with the atmosphere of a constructed wetland treating wastewater. Parameters and implications for emission factors

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, A.E.; Svenssom, B.H. [Linkoeing Univ. (Sweden). Dept. of Water and Environmental Studies; Kasimir Klemedtsson, Aa. [Trollhaettan/Uddevalla Univ. College, Trollhaettan (Sweden). Dept. of Informatics and Mathematics; Klemedtsson, L. [Goeteborg Univ. (Sweden). Botanical Inst.


    Static chamber measurements of N{sub 2}O fluxes were taken during the 1998 and 1999 growth seasons in a Swedish constructed wetland receiving wastewater. The dominating plant species in different parts of the wetland were Lemna minor L., Typha latifolia L., Spirogyra sp. and Glyceria maxima (Hartm.) and Phalaris arundinacea (L.), respectively. There were large temporal and spatial variations in N{sub 2}O fluxes, which ranged from consumption at -350 to emissions at 1791 {mu}g N{sub 2}O/m{sup 2}/h. The largest positive flux occurred in October 1999 and the lowest in the middle of July 1999. The average N{sub 2}O flux for the two years was 130 {mu}g N{sub 2}O/m{sup 2}/h (SD = 220). No significant differences in N{sub 2}O fluxes were found between the years, even though the two growing seasons differed considerably with respect to both air temperature and precipitation. 15% of the fluxes were negative, showing a consumption of N{sub 2}O. Consumption occurred on a few occasions at most measurement sites and ranged from 1 - 350 {mu}g N{sub 2}O/m{sup 2}/h. 13 - 43% of the variation in N{sub 2}O fluxes was explained by multiple linear regression analysis including principal components. Emission factors were calculated according to IPCC methods from the N{sub 2}O fluxes in the constructed wetland. The calculated emission factors were always lower (0.02 - 0.27%) compared to the default factor provided by the IPCC (0.75%). Thus, direct application of the IPCC default factor may lead to overestimation of N{sub 2}O fluxes from constructed wastewater-treating wetlands.

  19. Hydrogen exchange

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Rand, Kasper Dyrberg


    Hydrogen exchange (HX) monitored by mass spectrometry (MS) is a powerful analytical method for investigation of protein conformation and dynamics. HX-MS monitors isotopic exchange of hydrogen in protein backbone amides and thus serves as a sensitive method for probing protein conformation...... and dynamics along the entire protein backbone. This chapter describes the exchange of backbone amide hydrogen which is highly quenchable as it is strongly dependent on the pH and temperature. The HX rates of backbone amide hydrogen are sensitive and very useful probes of protein conformation......, as they are distributed along the polypeptide backbone and form the fundamental hydrogen-bonding networks of basic secondary structure. The effect of pressure on HX in unstructured polypeptides (poly-dl-lysine and oxidatively unfolded ribonuclease A) and native folded proteins (lysozyme and ribonuclease A) was evaluated...

  20. Transforming Growth Factor β2 Promotes Transcription of COX2 and EP4, Leading to a Prostaglandin E2-Driven Autostimulatory Loop That Enhances Virulence of Theileria annulata-Transformed Macrophages (United States)

    Echebli, Nadia; Ding, Ying; Kamau, Everlyn


    Transforming growth factor beta (TGF-β) is a pleiotropic cytokine known to regulate cell growth, differentiation, and motility and is a potent modulator of immune function. TGF-β consequently plays a central role in carcinogenesis, and a dampened TGF-β2 response by Theileria annulata-infected monocytes/macrophages underpins disease resistance to tropical theileriosis. Here, we show that concomitant with the loss of TGF-β2 production, there is ablated expression of COX2 and EP4, which leads to a drop in cyclic AMP (cAMP) levels and, consequently, reduced activation of protein kinase A (PKA) and EPAC. This ablated phenotype can be rescued in attenuated macrophages by the addition of exogenous TGF-β2, which reactivates the expression of COX2 and EP4 while repressing that of protein kinase inhibitor gamma (PKIG) to the levels in virulent macrophages. TGF-β2 therefore promotes the adhesion and invasiveness of virulent macrophages by modulating COX2, EP4, and PKIG transcription to initiate a prostaglandin E2 (PGE2)-driven autostimulatory loop that augments PKA and EPAC activities. A virulence phenotype stemming from the double activation of PKA and EPAC is the induction of a CREB-mediated transcriptional program and the upregulation of JAM-L- and integrin 4αβ1-mediated adhesion of Theileria-infected macrophages. PMID:25690101

  1. A three-factor Doehlert matrix design in optimising the determination of octadecyltrimethylammonium bromide by cation-exchange chromatography with suppressed conductivity detection. (United States)

    Cataldi, Tommaso R I; Orlando, Donatella; Nardiello, Donatella; Rubino, Alessandra; Bianco, Giuliana; Abate, Salvatore; Ciriello, Rosanna; Guerrieri, Antonio


    A simple and effective chromatographic method with suppressed conductivity detection was developed and validated to determine dissolved samples of octadecyltrimethylammonium bromide (C18H37N+ Me3Br-, ODTAB) for purity testing. A response surface methodology generated with a Doehlert matrix design was applied to optimize the chromatographic and detection conditions in ion-exchange chromatography (IEC) with conductivity detection in the chemical suppression mode. A three-factor Doehlert design was performed to fit a second-order model and jointly optimize the peak intensity and shorten analysis time through a global desirability function. Regenerant flow rate, volume fraction of acetonitrile in the acidic eluent and its flow rate were studied at seven, five and three levels, respectively. The optimized separation and detection conditions were accomplished by using a cation-exchange column eluted at 0.5 mL min(-1) with an isocratic mobile phase composed of CH3CN and 25 mN H2SO4, 82/18 (v/v). Chemical suppression of ionic conductivity was performed by 100 mN tetrabutylammonium hydroxide (TBAOH) as a regenerant at a flow-rate of 4.0 mL min(-1). Remarkably good agreement was found between predicted and experimental values of signal intensity and chromatographic retention. With the developed method, a linear calibration curve of ODTA+ as bromide salt from 5 to 1000 ppm was obtained using hexadecyltrimethylammonium bromide as internal standard. The estimated limit of detection was 0.3 ppm (S/N=3). The effectiveness of electrochemically suppressed conductivity detection of ODTA+ was also demonstrated, thus making easier the whole detection operation and instrumental needs as well.

  2. Sister chromatid exchange and micronucleus frequency in human lymphocytes of 1,650 subjects in an Italian population: I. Contribution of methodological factors. (United States)

    Barale, R; Marrazzini, A; Bacci, E; Di Sibio, A; Tessa, A; Cocchi, L; Scarcelli, V; Lubrano, V; Vassalle, C; Landi, S


    The influence of several methodological factors on mean values of sister chromatid exchanges (SCEs) and micronuclei (MN) in peripheral lymphocytes of 1,650 subjects was analyzed. Donors belonged to a general healthy population living in Pisa and in two nearby small cities: Cascina and Navacchio (Ca-Na). Blood samples were collected over a period of 29 months and processed in three different laboratories of the some institute. Slides were analyzed by several scorers. Our data showed that lymphocyte proliferation indexes (PIs) and baseline mean values of SCEs were affected mainly by sampling period. This factor accounted for a percentage ranging from roughly 10% (Pisa) to 20% (Ca-Na) of total SCE variance and from roughly 10% (Pisa) to 13% (Ca-Na) of total PIs variance. A marginal effect was attributable to the different laboratories involved (maximum 3% for SCEs and 7% for PIs). The sampling period variable included many sources of variability such as culture media batches, fetal calf serum, PHA, BrdUrd, and seasonality. MN counts revealed a more marked dependence on processing laboratories. This factor accounted for a percentage of roughly 10% (Pisa and Ca-Na) of total variance, while the sampling period was marginally effective (about 1-4% of total variability). Because laboratories were equipped and supplied with the same materials and consumables and technicians were rotated constantly, the only variable ascertained was represented by the three different models of CO2 incubators used for lymphocyte culturing. When "month" and "incubator" variables were considered jointly, experimental variability accounted for 15-20% of total variance, both for PIs and mean values SCEs and MN. The variability due to slide scoring was reduced by assigning each slide to five different scorers and matching low with high scorers in each group. Present data show that when the study is performed under these controlled conditions, about 20% of total interdonor variability can be

  3. MtbHLH1, a bHLH transcription factor involved in Medicago truncatula nodule vascular patterning and nodule to plant metabolic exchanges (United States)

    Godiard, Laurence; Lepage, Agnès; Moreau, Sandra; Laporte, Damien; Verdenaud, Marion; Timmers, Ton; Gamas, Pascal


    This study aimed at defining the role of a basic helix–loop–helix (bHLH) transcription factor gene from Medicago truncatula, MtbHLH1, whose expression is upregulated during the development of root nodules produced upon infection by rhizobia bacteria. We used MtbHLH1 promoter::GUS fusions and quantitative reverse-transcription polymerase chain reaction analyses to finely characterize the MtbHLH1 expression pattern. We altered MtbHLH1 function by expressing a dominantly repressed construct (CRES-T approach) and looked for possible MtbHLH1 target genes by transcriptomics. We found that MtbHLH1 is expressed in nodule primordia cells derived from pericycle divisions, in nodule vascular bundles (VBs) and in uninfected cells of the nitrogen (N) fixation zone. MtbHLH1 is also expressed in root tips, lateral root primordia cells and root VBs, and induced upon auxin treatment. Altering MtbHLH1 function led to an unusual phenotype, with a modified patterning of nodule VB development and a reduced growth of aerial parts of the plant, even though the nodules were able to fix atmospheric N. Several putative MtbHLH1 regulated genes were identified, including an asparagine synthase and a LOB (lateral organ boundary) transcription factor. Our results suggest that the MtbHLH1 gene is involved in the control of nodule vasculature patterning and nutrient exchanges between nodules and roots. PMID:21679315

  4. Unique classes of mutations in the Saccharomyces cerevisiae G-protein translation elongation factor 1A suppress the requirement for guanine nucleotide exchange. (United States)

    Ozturk, Sedide B; Vishnu, Melanie R; Olarewaju, Olubunmi; Starita, Lea M; Masison, Daniel C; Kinzy, Terri Goss


    G-proteins play critical roles in many cellular processes and are regulated by accessory proteins that modulate the nucleotide-bound state. Such proteins, including eukaryotic translation elongation factor 1A (eEF1A), are frequently reactivated by guanine nucleotide exchange factors (GEFs). In the yeast Saccharomyces cerevisiae, only the catalytic subunit of the GEF complex, eEF1Balpha, is essential for viability. The requirement for the TEF5 gene encoding eEF1Balpha can be suppressed by the presence of excess substrate, eEF1A. These cells, however, have defects in growth and translation. Two independent unbiased screens performed to dissect the cause of these phenotypes yielded dominant suppressors that bypass the requirement for extra eEF1A. Surprisingly, all mutations are in the G-protein eEF1A and cluster in its GTP-binding domain. Five mutants were used to construct novel strains expressing only the eEF1A mutant at normal levels. These strains show no growth defects and little to no decreases in total translation, which raises questions as to the evolutionary expression of GEF complexity and other potential functions of this complex. The location of the mutations on the eEF1A-eEF1Balpha structure suggests that their mechanism of suppression may depend on effects on the conserved G-protein elements: the P-loop and NKXD nucleotide-binding element.

  5. Exchange Options

    NARCIS (Netherlands)

    Jamshidian, F.


    The contract is described and market examples given. Essential theoretical developments are introduced and cited chronologically. The principles and techniques of hedging and unique pricing are illustrated for the two simplest nontrivial examples: the classical Black-Scholes/Merton/Margrabe exchange

  6. Climate and site management as driving factors for the atmospheric greenhouse gas exchange of a restored wetland

    Directory of Open Access Journals (Sweden)

    M. Herbst


    Full Text Available The atmospheric greenhouse gas (GHG budget of a restored wetland in western Denmark was established for the years 2009–2011 from eddy covariance measurements of carbon dioxide (CO2 and methane (CH4 fluxes. The water table in the wetland, which was restored in 2002, was unregulated, and the vegetation height was limited through occasional grazing by cattle and grass cutting. The annual net CO2 uptake varied between 195 and 983 g m−2 and the annual net CH4 release varied between 11 and 17 g m−2. In all three years the wetland was a carbon sink and removed between 42 and 259 g C m−2 from the atmosphere. However, in terms of the full annual GHG budget (assuming that 1 g CH4 is equivalent to 25 g CO2 with respect to the greenhouse effect over a time horizon of 100 years the wetland was a sink in 2009, a source in 2010 and neutral in 2011. Complementary observations of meteorological factors and management activities were used to explain the large inter-annual variations in the full atmospheric GHG budget of the wetland. The largest impact on the annual GHG fluxes, eventually defining their sign, came from site management through changes in grazing duration and animal stocking density. These changes accounted for half of the observed variability in the CO2 fluxes and about two thirds of the variability in CH4 fluxes. An unusually long period of snow cover in 2010 had the second largest effect on the annual CO2 flux, whose interannual variability was larger than that of the CH4 flux. Since integrated CO2 and CH4 flux data from restored wetlands are still very rare, it is concluded that more long-term flux measurements are needed to quantify the effects of ecosystem disturbance, in terms of management activities and exceptional weather patterns, on the atmospheric GHG budget more

  7. The Bipartite Rac1 Guanine Nucleotide Exchange Factor Engulfment and Cell Motility 1/Dedicator of Cytokinesis 180 (Elmo1/Dock180) Protects Endothelial Cells from Apoptosis in Blood Vessel Development

    NARCIS (Netherlands)

    Schaeker, Kathrin; Bartsch, Susanne; Patry, Christian; Stoll, Sandra J.; Hillebrands, Jan-Luuk; Wieland, Thomas; Kroll, Jens


    Engulfment and cell motility 1/dedicator of cytokinesis 180 (Elmol/Dock180) is a bipartite guanine nucleotide exchange factor for the monomeric GTPase Ras-related C3 botulinum toxin substrate 1 (Racl). Elmol/Dock180 regulates Racl activity in a specific spatiotemporal manner in endothelial cells

  8. Ion exchange equilibrium constants

    CERN Document Server

    Marcus, Y


    Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and

  9. Multifaceted Roles of the Ras Guanine-Nucleotide Exchange Factor ChRgf in Development, Pathogenesis, and Stress Responses of Colletotrichum higginsianum. (United States)

    Gu, Qiongnan; Chen, Meijuan; Huang, Junbin; Wei, Yangdou; Hsiang, Tom; Zheng, Lu


    The infection process of Colletotrichum higginsianum, which causes a disease of crucifers, involves several key steps: conidial germination, appressorial formation, appressorial penetration, and invasive growth in host tissues. In this study, the ChRgf gene encoding a Ras guanine-nucleotide exchange factor protein was identified by screening T-DNA insertion mutants generated from Agrobacterium tumefaciens-mediated transformation that were unable to cause disease on the host Arabidopsis thaliana. Targeted gene deletion of ChRgf resulted in a null mutant (ΔChrgf-42) with defects in vegetative growth, hyphal morphology, and conidiation, and poor surface attachment and low germination on hydrophobic surfaces; however, there were no apparent differences in appressorial turgor pressure between the wild type and the mutant. The conidia of the mutant were unable to geminate on attached Arabidopsis leaves and did not cause any disease symptoms. Intracellular cyclic adenosine monophosphate levels in the ΔChrgf mutant were lower than that of the wild type. Our results suggest that ChRgf is a key regulator in response to salt and osmotic stresses in C. higginsianum, and indicate that it is involved in fungal pathogenicity. This gene seems to act as an important modulator upstream of several distinct signaling pathways that are involved in regulating vegetative growth, conidiation, infection-related structure development, and stress responses of C. higginsianum.

  10. The Rho-specific guanine nucleotide exchange factor Plekhg5 modulates cell polarity, adhesion, migration, and podosome organization in macrophages and osteoclasts. (United States)

    Iwatake, Mayumi; Nishishita, Kazuhisa; Okamoto, Kuniaki; Tsukuba, Takayuki


    Osteoclasts are multinucleated bone-resorbing cells that are formed by fusion of monocyte/macrophage lineage. Osteoclasts and macrophages generate podosomes that are actin-based dynamic organelles implicated in cell adhesion, spreading, migration, and degradation. However, the detailed mechanisms of podosome organization remain unknown. Here, we identified the Rho-specific guanine-nucleotide exchange factor (Rho-GEF) Plekhg5 as an up-regulated gene during differentiation of osteoclasts from macrophages. Knockdown of Plekhg5 with small interfering RNA in both macrophages and osteoclasts induced larger cell formation with impaired cell polarity and resulted in an elongated and flattened shape. In macrophages, Plekhg5 depletion enhanced random migration, but impaired directional migration, adhesion, and matrix degradation. Plekhg5 in osteoclasts affected random migration, podosome organization, and bone resorption. Plekhg5 depletion affected signaling and localization of several Rho downstream effectors. In fact, end-binding protein 1 (EB1), cofilin and vinculin were abnormally localized in Plekhg5-depleted cells, and mDia1 and LIM kinase (LIMK)1 were upregulated in Plekhg5-depleted cells compared with control cells. However, overexpression of Plekhg5 in macrophages induced an increase in its mRNA level, but failed to increase the protein level, indicating that overexpressed Plekhg5 was degraded in macrophages but not HEK293T cells. Thus, Plekhg5 affects cell polarity, migration, adhesion, degradation, and podosome organization in macrophages and osteoclasts. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. A bacterial cytotoxin identifies the RhoA exchange factor Net1 as a key effector in the response to DNA damage.

    Directory of Open Access Journals (Sweden)

    Lina Guerra

    Full Text Available BACKGROUND: Exposure of adherent cells to DNA damaging agents, such as the bacterial cytolethal distending toxin (CDT or ionizing radiations (IR, activates the small GTPase RhoA, which promotes the formation of actin stress fibers and delays cell death. The signalling intermediates that regulate RhoA activation and promote cell survival are unknown. PRINCIPAL FINDINGS: We demonstrate that the nuclear RhoA-specific Guanine nucleotide Exchange Factor (GEF Net1 becomes dephosphorylated at a critical inhibitory site in cells exposed to CDT or IR. Expression of a dominant negative Net1 or Net1 knock down by iRNA prevented RhoA activation, inhibited the formation of stress fibers, and enhanced cell death, indicating that Net1 activation is required for this RhoA-mediated responses to genotoxic stress. The Net1 and RhoA-dependent signals involved activation of the Mitogen-Activated Protein Kinase p38 and its downstream target MAPK-activated protein kinase 2. SIGNIFICANCE: Our data highlight the importance of Net1 in controlling RhoA and p38 MAPK mediated cell survival in cells exposed to DNA damaging agents and illustrate a molecular pathway whereby chronic exposure to a bacterial toxin may promote genomic instability.

  12. Na+/H+ exchange regulatory factor 1 is required for ROMK1 K+ channel expression in the surface membrane of cultured M-1 cortical collecting duct cells. (United States)

    Suzuki, Takashi; Nakamura, Kazuyoshi; Mayanagi, Taira; Sobue, Kenji; Kubokawa, Manabu


    The ROMK1 K+ channel, a member of the ROMK channel family, is the major candidate for the K+ secretion pathway in the renal cortical collecting duct (CCD). ROMK1 possesses a PDZ domain-binding motif at its C-terminus that is considered a modulator of ROMK1 expression via interaction with Na+/H+ exchange regulatory factor (NHERF) 1 and NHERF2 scaffold protein. Although NHERF1 is a potential binding partner of the ROMK1 K+ channel, the interaction between NHERF1 and K+ channel activity remains unclear. Therefore, in this study, we knocked down NHERF1 in cultured M-1 cells derived from mouse CCD and investigated the surface expression and K+ channel current in these cells after exogenous transfection with EGFP-ROMK1. NHERF1 knockdown resulted in reduced surface expression of ROMK1 as indicated by a cell biotinylation assay. Using the patch-clamp technique, we further found that the number of active channels per patched membrane and the Ba2+-sensitive whole-cell K+ current were decreased in the knockdown cells, suggesting that reduced K+ current was accompanied by decreased surface expression of ROMK1 in the NHERF1 knockdown cells. Our results provide evidence that NHERF1 mediates K+ current activity through acceleration of the surface expression of ROMK1 K+ channels in M-1 cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. An unexpected role for the yeast nucleotide exchange factor Sil1 as a reductant acting on the molecular chaperone BiP. (United States)

    Siegenthaler, Kevin D; Pareja, Kristeen A; Wang, Jie; Sevier, Carolyn S


    Unfavorable redox conditions in the endoplasmic reticulum (ER) can decrease the capacity for protein secretion, altering vital cell functions. While systems to manage reductive stress are well-established, how cells cope with an overly oxidizing ER remains largely undefined. In previous work (Wang et al., 2014), we demonstrated that the chaperone BiP is a sensor of overly oxidizing ER conditions. We showed that modification of a conserved BiP cysteine during stress beneficially alters BiP chaperone activity to cope with suboptimal folding conditions. How this cysteine is reduced to reestablish 'normal' BiP activity post-oxidative stress has remained unknown. Here we demonstrate that BiP's nucleotide exchange factor - Sil1 - can reverse BiP cysteine oxidation. This previously unexpected reductant capacity for yeast Sil1 has potential implications for the human ataxia Marinesco-Sjögren syndrome, where it is interesting to speculate that a disruption in ER redox-signaling (due to genetic defects in SIL1 ) may influence disease pathology.

  14. Role of the guanine nucleotide exchange factor in Akt2-mediated plasma membrane translocation of GLUT4 in insulin-stimulated skeletal muscle. (United States)

    Takenaka, Nobuyuki; Yasuda, Naoto; Nihata, Yuma; Hosooka, Tetsuya; Noguchi, Tetsuya; Aiba, Atsu; Satoh, Takaya


    The small GTPase Rac1 plays a key role in insulin-promoted glucose uptake mediated by the GLUT4 glucose transporter in skeletal muscle. Our recent studies have demonstrated that the serine/threonine protein kinase Akt2 is critically involved in insulin-dependent Rac1 activation. The purpose of this study is to clarify the role of the guanine nucleotide exchange factor FLJ00068 in Akt2-mediated Rac1 activation and GLUT4 translocation in mouse skeletal muscle and cultured myocytes. Constitutively activated FLJ00068 induced GLUT4 translocation in a Rac1-dependent and Akt2-independent manner in L6 myocytes. On the other hand, knockdown of FLJ00068 significantly reduced constitutively activated Akt2-triggered GLUT4 translocation. Furthermore, Rac1 activation and GLUT4 translocation induced by constitutively activated phosphoinositide 3-kinase were inhibited by knockdown of FLJ00068. In mouse gastrocnemius muscle, constitutively activated FLJ00068 actually induced GLUT4 translocation to the sarcolemma. GLUT4 translocation by constitutively activated FLJ00068 was totally abolished in rac1 knockout mouse gastrocnemius muscle. Additionally, we were successful in detecting the activation of Rac1 following the expression of constitutively activated FLJ00068 in gastrocnemius muscle by immunofluorescence microscopy using an activation-specific probe. Collectively, these results strongly support the notion that FLJ00068 regulates Rac1 downstream of Akt2, leading to the stimulation of glucose uptake in skeletal muscle. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Epitope mapping of inhibitory antibodies targeting the C2 domain of coagulation factor VIII by hydrogen-deuterium exchange mass spectrometry (United States)

    Sevy, Alexander M.; Healey, John F.; Deng, Wei; Spiegel, P. Clint; Meeks, Shannon L.; Li, Renhao


    Summary Background The development of anti-factor VIII (fVIII) antibodies (inhibitors) is a significant complication in the management of patients with hemophilia A, leading to significant increases in morbidity and treatment cost. Using a panel of anti-fVIII monoclonal antibodies (MAbs) to different epitopes on fVIII, we recently have shown that epitope specificity, inhibitor kinetics, and time to maximum inhibition are more important than inhibitor titer in predicting response to fVIII and the combination of fVIII and recombinant factor VIIa. In particular, a subset of high-titer inhibitors responded to high dose fVIII, which would not be predicted based on their inhibitor titer alone. Thus the ability to quickly map the epitope spectrum of patient plasma using a clinically feasible assay may fundamentally change how clinicians approach the treatment of high-titer inhibitor patients. Objectives To map the epitopes of anti-fVIII MAbs, of which 3 are classical inhibitors and one non-classical, using hydrogen-deuterium exchange coupled with liquid chromatography-mass spectrometry (HDX-MS). Methods Binding epitopes of 4 MAbs targeting fVIII C2 domain were mapped using HDX-MS. Results The epitopes determined by HDX-MS are consistent with those obtained earlier through structural characterization and antibody competition assays. In addition classical and non-classical inhibitor epitopes could be distinguished using a limited subset of C2-derived peptic fragments. Conclusion Our results demonstrate the effectiveness and robustness of the HDX-MS method for epitope mapping and suggest a potential role of rapid mapping of fVIII inhibitor epitopes in facilitating individualized treatment of inhibitor patients. PMID:24152306

  16. The signaling pathway of Campylobacter jejuni-induced Cdc42 activation: Role of fibronectin, integrin beta1, tyrosine kinases and guanine exchange factor Vav2

    LENUS (Irish Health Repository)

    Krause-Gruszczynska, Malgorzata


    Abstract Background Host cell invasion by the foodborne pathogen Campylobacter jejuni is considered as one of the primary reasons of gut tissue damage, however, mechanisms and key factors involved in this process are widely unclear. It was reported that small Rho GTPases, including Cdc42, are activated and play a role during invasion, but the involved signaling cascades remained unknown. Here we utilised knockout cell lines derived from fibronectin-\\/-, integrin-beta1-\\/-, focal adhesion kinase (FAK)-\\/- and Src\\/Yes\\/Fyn-\\/- deficient mice, and wild-type control cells, to investigate C. jejuni-induced mechanisms leading to Cdc42 activation and bacterial uptake. Results Using high-resolution scanning electron microscopy, GTPase pulldowns, G-Lisa and gentamicin protection assays we found that each studied host factor is necessary for induction of Cdc42-GTP and efficient invasion. Interestingly, filopodia formation and associated membrane dynamics linked to invasion were only seen during infection of wild-type but not in knockout cells. Infection of cells stably expressing integrin-beta1 variants with well-known defects in fibronectin fibril formation or FAK signaling also exhibited severe deficiencies in Cdc42 activation and bacterial invasion. We further demonstrated that infection of wild-type cells induces increasing amounts of phosphorylated FAK and growth factor receptors (EGFR and PDGFR) during the course of infection, correlating with accumulating Cdc42-GTP levels and C. jejuni invasion over time. In studies using pharmacological inhibitors, silencing RNA (siRNA) and dominant-negative expression constructs, EGFR, PDGFR and PI3-kinase appeared to represent other crucial components upstream of Cdc42 and invasion. siRNA and the use of Vav1\\/2-\\/- knockout cells further showed that the guanine exchange factor Vav2 is required for Cdc42 activation and maximal bacterial invasion. Overexpression of certain mutant constructs indicated that Vav2 is a linker

  17. Timing Foreign Exchange Markets

    Directory of Open Access Journals (Sweden)

    Samuel W. Malone


    Full Text Available To improve short-horizon exchange rate forecasts, we employ foreign exchange market risk factors as fundamentals, and Bayesian treed Gaussian process (BTGP models to handle non-linear, time-varying relationships between these fundamentals and exchange rates. Forecasts from the BTGP model conditional on the carry and dollar factors dominate random walk forecasts on accuracy and economic criteria in the Meese-Rogoff setting. Superior market timing ability for large moves, more than directional accuracy, drives the BTGP’s success. We explain how, through a model averaging Monte Carlo scheme, the BTGP is able to simultaneously exploit smoothness and rough breaks in between-variable dynamics. Either feature in isolation is unable to consistently outperform benchmarks throughout the full span of time in our forecasting exercises. Trading strategies based on ex ante BTGP forecasts deliver the highest out-of-sample risk-adjusted returns for the median currency, as well as for both predictable, traded risk factors.

  18. The nuclear guanine nucleotide exchange factors Ect2 and Net1 regulate RhoB-mediated cell death after DNA damage.

    Directory of Open Access Journals (Sweden)

    Melissa C Srougi


    Full Text Available Commonly used antitumor treatments, including radiation and chemotherapy, function by damaging the DNA of rapidly proliferating cells. However, resistance to these agents is a predominant clinical problem. A member of the Rho family of small GTPases, RhoB has been shown to be integral in mediating cell death after ionizing radiation (IR or other DNA damaging agents in Ras-transformed cell lines. In addition, RhoB protein expression increases after genotoxic stress, and loss of RhoB expression causes radio- and chemotherapeutic resistance. However, the signaling pathways that govern RhoB-induced cell death after DNA damage remain enigmatic. Here, we show that RhoB activity increases in human breast and cervical cancer cell lines after treatment with DNA damaging agents. Furthermore, RhoB activity is necessary for DNA damage-induced cell death, as the stable loss of RhoB protein expression using shRNA partially protects cells and prevents the phosphorylation of c-Jun N-terminal kinases (JNKs and the induction of the pro-apoptotic protein Bim after IR. The increase in RhoB activity after genotoxic stress is associated with increased activity of the nuclear guanine nucleotide exchange factors (GEFs, Ect2 and Net1, but not the cytoplasmic GEFs p115 RhoGEF or Vav2. Importantly, loss of Ect2 and Net1 via siRNA-mediated protein knock-down inhibited IR-induced increases in RhoB activity, reduced apoptotic signaling events, and protected cells from IR-induced cell death. Collectively, these data suggest a mechanism involving the nuclear GEFs Ect2 and Net1 for activating RhoB after genotoxic stress, thereby facilitating cell death after treatment with DNA damaging agents.

  19. Cool-1/βPIX functions as a guanine nucleotide exchange factor in the cycling of Cdc42 to regulate insulin secretion. (United States)

    Kepner, Erica M; Yoder, Stephanie M; Oh, Eunjin; Kalwat, Michael A; Wang, Zhanxiang; Quilliam, Lawrence A; Thurmond, Debbie C


    Second-phase insulin release requires the sustained mobilization of insulin granules from internal storage pools to the cell surface for fusion with the plasma membrane. However, the detailed mechanisms underlying this process remain largely unknown. GTP-loading of the small GTPase Cdc42 is the first glucose-specific activation step in the process, although how glucose triggers Cdc42 activation is entirely unknown. In a directed candidate screen for guanine nucleotide exchange factors (GEFs), which directly activate small GTPases, Cool-1/βPix was identified in pancreatic islet beta cells. In support of its role as the beta cell Cdc42 GEF, βPix coimmunoprecipitated with Cdc42 in human islets and MIN6 beta cells in a glucose-dependent manner, peaking just prior to Cdc42 activation. Furthermore, RNAi-mediated βPix reduction by 50% corresponded to full ablation of glucose-induced Cdc42 activation and significant attenuation of basal and glucose-stimulated insulin secretion. Of the two Cdc42 guanine nucleotide dissociation inhibitor (GDI) proteins identified in beta cells, βPix competed selectively with caveolin-1 (Cav-1) but not RhoGDI in coimmunoprecipitation and GST-Cdc42-GDP interaction assays. However, a phospho-deficient Cav-1-Y14F mutant failed to compete with βPix; Cav-1(Tyr14) is an established phosphorylation site for Src kinase. Taken together, these data support a new model, wherein glucose stimulates Cav-1 and induces its dissociation from Cdc42, possibly via Src kinase activation to phosphorylate Cav-1(Tyr14), to promote Cdc42-βPix binding and Cdc42 activation, and to trigger downstream signaling and ultimately sustain insulin release.

  20. Control of cerebellar long-term potentiation by P-Rex-family guanine-nucleotide exchange factors and phosphoinositide 3-kinase.

    Directory of Open Access Journals (Sweden)

    Claire Jackson


    Full Text Available Long-term potentiation (LTP at the parallel fibre-Purkinje cell synapse in the cerebellum is a recently described and poorly characterized form of synaptic plasticity. The induction mechanism for LTP at this synapse is considered reciprocal to "classical" LTP at hippocampal CA1 pyramidal neurons: kinases promote increased trafficking of AMPA receptors into the postsynaptic density in the hippocampus, whereas phosphatases decrease internalization of AMPA receptors in the cerebellum. In the hippocampus, LTP occurs in overlapping phases, with the transition from early to late phases requiring the consolidation of initial induction processes by structural re-arrangements at the synapse. Many signalling pathways have been implicated in this process, including PI3 kinases and Rho GTPases.We hypothesized that analogous phases are present in cerebellar LTP, and took as the starting point for investigation our recent discovery that P-Rex--a Rac guanine nucleotide exchange factor which is activated by PtdIns(3,4,5P(3--is highly expressed in mouse cerebellar Purkinje neurons and plays a role in motor coordination. We found that LTP evoked at parallel fibre synapses by 1 Hz stimulation or by NO donors was not sustained beyond 30 min when P-Rex was eliminated or Rac inhibited, suggesting that cerebellar LTP exhibits a late phase analogous to hippocampal LTP. In contrast, inhibition of PI3 kinase activity eliminated LTP at the induction stage.Our data suggest that a PI3K/P-Rex/Rac pathway is required for late phase LTP in the mouse cerebellum, and that other PI3K targets, which remain to be discovered, control LTP induction.

  1. Rac1 Activation Caused by Membrane Translocation of a Guanine Nucleotide Exchange Factor in Akt2-Mediated Insulin Signaling in Mouse Skeletal Muscle.

    Directory of Open Access Journals (Sweden)

    Nobuyuki Takenaka

    Full Text Available Insulin-stimulated glucose uptake in skeletal muscle is mediated by the glucose transporter GLUT4, which is translocated to the plasma membrane following insulin stimulation. Several lines of evidence suggested that the protein kinase Akt2 plays a key role in this insulin action. The small GTPase Rac1 has also been implicated as a regulator of insulin-stimulated GLUT4 translocation, acting downstream of Akt2. However, the mechanisms whereby Akt2 regulates Rac1 activity remain obscure. The guanine nucleotide exchange factor FLJ00068 has been identified as a direct regulator of Rac1 in Akt2-mediated signaling, but its characterization was performed mostly in cultured myoblasts. Here, we provide in vivo evidence that FLJ00068 indeed acts downstream of Akt2 as a Rac1 regulator by using mouse skeletal muscle. Small interfering RNA knockdown of FLJ00068 markedly diminished GLUT4 translocation to the sarcolemma following insulin administration or ectopic expression of a constitutively activated mutant of either phosphoinositide 3-kinase or Akt2. Additionally, insulin and these constitutively activated mutants caused the activation of Rac1 as shown by immunofluorescent microscopy using a polypeptide probe specific to activated Rac1 in isolated gastrocnemius muscle fibers and frozen sections of gastrocnemius muscle. This Rac1 activation was also abrogated by FLJ00068 knockdown. Furthermore, we observed translocation of FLJ00068 to the cell periphery following insulin stimulation in cultured myoblasts. Localization of FLJ00068 in the plasma membrane in insulin-stimulated, but not unstimulated, myoblasts and mouse gastrocnemius muscle was further affirmed by subcellular fractionation and subsequent immunoblotting. Collectively, these results strongly support a critical role of FLJ00068 in Akt2-mediated Rac1 activation in mouse skeletal muscle insulin signaling.

  2. Release of GTP Exchange Factor Mediated Down-Regulation of Abscisic Acid Signal Transduction through ABA-Induced Rapid Degradation of RopGEFs (United States)

    Waadt, Rainer; Schroeder, Julian I.


    The phytohormone abscisic acid (ABA) is critical to plant development and stress responses. Abiotic stress triggers an ABA signal transduction cascade, which is comprised of the core components PYL/RCAR ABA receptors, PP2C-type protein phosphatases, and protein kinases. Small GTPases of the ROP/RAC family act as negative regulators of ABA signal transduction. However, the mechanisms by which ABA controls the behavior of ROP/RACs have remained unclear. Here, we show that an Arabidopsis guanine nucleotide exchange factor protein RopGEF1 is rapidly sequestered to intracellular particles in response to ABA. GFP-RopGEF1 is sequestered via the endosome-prevacuolar compartment pathway and is degraded. RopGEF1 directly interacts with several clade A PP2C protein phosphatases, including ABI1. Interestingly, RopGEF1 undergoes constitutive degradation in pp2c quadruple abi1/abi2/hab1/pp2ca mutant plants, revealing that active PP2C protein phosphatases protect and stabilize RopGEF1 from ABA-mediated degradation. Interestingly, ABA-mediated degradation of RopGEF1 also plays an important role in ABA-mediated inhibition of lateral root growth. The presented findings point to a PP2C-RopGEF-ROP/RAC control loop model that is proposed to aid in shutting off ABA signal transduction, to counteract leaky ABA signal transduction caused by “monomeric” PYL/RCAR ABA receptors in the absence of stress, and facilitate signaling in response to ABA. PMID:27192441

  3. Release of GLP-1 and PYY in response to the activation of G protein-coupled bile acid receptor TGR5 is mediated by Epac/PLC-ε pathway and modulated by endogenous H2S. (United States)

    Bala, Vanitha; Rajagopal, Senthilkumar; Kumar, Divya P; Nalli, Ancy D; Mahavadi, Sunila; Sanyal, Arun J; Grider, John R; Murthy, Karnam S


    Activation of plasma membrane TGR5 receptors in enteroendocrine cells by bile acids is known to regulate gastrointestinal secretion and motility and glucose homeostasis. The endocrine functions of the gut are modulated by microenvironment of the distal gut predominantly by sulfur-reducing bacteria of the microbiota that produce H2S. However, the mechanisms involved in the release of peptide hormones, GLP-1 and PYY in response to TGR5 activation by bile acids and the effect of H2S on bile acid-induced release of GLP-1 and PYY are unclear. In the present study, we have identified the signaling pathways activated by the bile acid receptor TGR5 to mediate GLP-1 and PYY release and the mechanism of inhibition of their release by H2S in enteroendocrine cells. The TGR5 ligand oleanolic acid (OA) stimulated Gαs and cAMP formation, and caused GLP-1 and PYY release. OA-induced cAMP formation and peptide release were blocked by TGR5 siRNA. OA also caused an increase in PI hydrolysis and intracellular Ca(2+). Increase in PI hydrolysis was abolished in cells transfected with PLC-ε siRNA. 8-pCPT-2'-O-Me-cAMP, a selective activator of Epac, stimulated PI hydrolysis, and GLP-1 and PYY release. L-Cysteine, which activates endogenous H2S producing enzymes cystathionine-γ-lyase and cystathionine-β-synthase, and NaHS and GYY4137, which generate H2S, inhibited PI hydrolysis and GLP-1 and PYY release in response to OA or 8-pCPT-2'-O-Me-cAMP. Propargylglycine, an inhibitor of CSE, reversed the effect of L-cysteine on PI hydrolysis and GLP-1 and PYY release. We conclude: (i) activation of Gαs-coupled TGR5 receptors causes stimulation of PI hydrolysis, and release of GLP-1 and PYY via a PKA-independent, cAMP-dependent mechanism involving Epac/PLC-ε/Ca(2+) pathway, and (ii) H2S has potent inhibitory effects on GLP-1 and PYY release in response to TGR5 activation, and the mechanism involves inhibition of PLC-ε/Ca(2+) pathway.

  4. Segmented heat exchanger (United States)

    Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann


    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  5. Counterflow Regolith Heat Exchanger (United States)

    Zubrin, Robert; Jonscher, Peter


    A problem exists in reducing the total heating power required to extract oxygen from lunar regolith. All such processes require heating a great deal of soil, and the heat energy is wasted if it cannot be recycled from processed material back into new material. The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat exchanger with internal and external augers attached to the inner rotating tube to move the regolith. Hot regolith in the outer tube is moved in one direction by a right-hand - ed auger, and the cool regolith in the inner tube is moved in the opposite direction by a left-handed auger attached to the inside of the rotating tube. In this counterflow arrangement, a large fraction of the heat from the expended regolith is transferred to the new regolith. The spent regolith leaves the heat exchanger close to the temperature of the cold new regolith, and the new regolith is pre-heated close to the initial temperature of the spent regolith. Using the CoRHE can reduce the heating requirement of a lunar ISRU system by 80%, reducing the total power consumption by a factor of two. The unique feature of this system is that it allows for counterflow heat exchange to occur between solids, instead of liquids or gases, as is commonly done. In addition, in variants of this concept, the hydrogen reduction can be made to occur within the counterflow heat exchanger itself, enabling a simplified lunar ISRU (in situ resource utilization) system with excellent energy economy and continuous nonbatch mode operation.

  6. Investigating the effects of liquidity and exchange rate on Tehran Stock Exchange

    Directory of Open Access Journals (Sweden)

    Younos Vakil Alroaia


    Full Text Available This paper presents an empirical investigation to study the effects of two macroeconomic factors; namely exchange rate and liquidity on stock index. The proposed study was applied in Iran and on major index of Tehran Stock Exchange over the period 2001-2011. They reported that the currency exchange maintained negative impact on stock exchange for the period of investigation. This is due to the fact that when currency devalued, working capital decreases and firms did not enough money to purchase raw materials, pay wages, etc. In addition, liquidity marinated a direct and positive relationship with exchange index. However, the impact of liquidity seems to be bigger than currency exchange.

  7. Australian Universities' Strategic Goals of Student Exchange and Participation Rates in Outbound Exchange Programmes (United States)

    Daly, Amanda; Barker, Michelle


    International student exchange programmes are acknowledged as one aspect of a broader suite of internationalisation strategies aimed at enhancing students' intercultural understanding and competence. The decision to participate in an exchange programme is dependent on both individual and contextual factors such as student exchange policies and…

  8. The amino acid exchange R28E in ciliary neurotrophic factor (CNTF) abrogates interleukin-6 receptor-dependent but retains CNTF receptor-dependent signaling via glycoprotein 130 (gp130)/leukemia inhibitory factor receptor (LIFR). (United States)

    Wagener, Eva-Maria; Aurich, Matthias; Aparicio-Siegmund, Samadhi; Floss, Doreen M; Garbers, Christoph; Breusing, Kati; Rabe, Björn; Schwanbeck, Ralf; Grötzinger, Joachim; Rose-John, Stefan; Scheller, Jürgen


    Ciliary neurotrophic factor (CNTF) is a neurotrophic factor with therapeutic potential for neurodegenerative diseases. Moreover, therapeutic application of CNTF reduced body weight in mice and humans. CNTF binds to high or low affinity receptor complexes consisting of CNTFR·gp130·LIFR or IL-6R·gp130·LIFR, respectively. Clinical studies of the CNTF derivative Axokine revealed intolerance at higher concentrations, which may rely on the low-affinity binding of CNTF to the IL-6R. Here, we aimed to generate a CNTFR-selective CNTF variant (CV). CV-1 contained the single amino acid exchange R28E. Arg(28) is in close proximity to the CNTFR binding site. Using molecular modeling, we hypothesized that Arg(28) might contribute to IL-6R/CNTFR plasticity of CNTF. CV-2 to CV-5 were generated by transferring parts of the CNTFR-binding site from cardiotrophin-like cytokine to CNTF. Cardiotrophin-like cytokine selectively signals via the CNTFR·gp130·LIFR complex, albeit with a much lower affinity compared with CNTF. As shown by immunoprecipitation, all CNTF variants retained the ability to bind to CNTFR. CV-1, CV-2, and CV-5, however, lost the ability to bind to IL-6R. Although all variants induced cytokine-dependent cellular proliferation and STAT3 phosphorylation via CNTFR·gp130·LIFR, only CV-3 induced STAT3 phosphorylation via IL-6R·gp130·LIFR. Quantification of CNTF-dependent proliferation of CNTFR·gp130·LIFR expressing cells indicated that only CV-1 was as biologically active as CNTF. Thus, the CNTFR-selective CV-1 will allow discriminating between CNTFR- and IL-6R-mediated effects in vivo. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. The Amino Acid Exchange R28E in Ciliary Neurotrophic Factor (CNTF) Abrogates Interleukin-6 Receptor-dependent but Retains CNTF Receptor-dependent Signaling via Glycoprotein 130 (gp130)/Leukemia Inhibitory Factor Receptor (LIFR)* (United States)

    Wagener, Eva-Maria; Aurich, Matthias; Aparicio-Siegmund, Samadhi; Floss, Doreen M.; Garbers, Christoph; Breusing, Kati; Rabe, Björn; Schwanbeck, Ralf; Grötzinger, Joachim; Rose-John, Stefan; Scheller, Jürgen


    Ciliary neurotrophic factor (CNTF) is a neurotrophic factor with therapeutic potential for neurodegenerative diseases. Moreover, therapeutic application of CNTF reduced body weight in mice and humans. CNTF binds to high or low affinity receptor complexes consisting of CNTFR·gp130·LIFR or IL-6R·gp130·LIFR, respectively. Clinical studies of the CNTF derivative Axokine revealed intolerance at higher concentrations, which may rely on the low-affinity binding of CNTF to the IL-6R. Here, we aimed to generate a CNTFR-selective CNTF variant (CV). CV-1 contained the single amino acid exchange R28E. Arg28 is in close proximity to the CNTFR binding site. Using molecular modeling, we hypothesized that Arg28 might contribute to IL-6R/CNTFR plasticity of CNTF. CV-2 to CV-5 were generated by transferring parts of the CNTFR-binding site from cardiotrophin-like cytokine to CNTF. Cardiotrophin-like cytokine selectively signals via the CNTFR·gp130·LIFR complex, albeit with a much lower affinity compared with CNTF. As shown by immunoprecipitation, all CNTF variants retained the ability to bind to CNTFR. CV-1, CV-2, and CV-5, however, lost the ability to bind to IL-6R. Although all variants induced cytokine-dependent cellular proliferation and STAT3 phosphorylation via CNTFR·gp130·LIFR, only CV-3 induced STAT3 phosphorylation via IL-6R·gp130·LIFR. Quantification of CNTF-dependent proliferation of CNTFR·gp130·LIFR expressing cells indicated that only CV-1 was as biologically active as CNTF. Thus, the CNTFR-selective CV-1 will allow discriminating between CNTFR- and IL-6R-mediated effects in vivo. PMID:24802752

  10. Sites involved in intra- and interdomain allostery associated with the activation of factor VIIa pinpointed by hydrogen-deuterium exchange and electron transfer dissociation mass spectrometry

    DEFF Research Database (Denmark)

    Song, Hongjian; Olsen, Ole H; Persson, Egon


    enhancement remain elusive. Here we have applied hydrogen/deuterium exchange mass spectrometry coupled to electron transfer dissociation to pinpoint individual residues in the heavy chain of FVIIa whose conformation and/or local interaction pattern changes when the enzyme transitions to the active form...

  11. Totalization Data Exchange (TDEX) (United States)

    Social Security Administration — The Totalization Data Exchange (TDEX) process is an exchange between SSA and its foreign country partners to identify deaths of beneficiaries residing abroad. The...

  12. The determinants of exchange rate in Croatia

    Directory of Open Access Journals (Sweden)

    Manuel BENAZIC


    Full Text Available The dilemma for every country with an independent monetary policy is which kind of exchange rate arrangement should be applied. Through the exchange rate policy, countries can influence their economies, i.e. price stability and export competiveness. Croatia is a new EU member state, it has its own monetary policy and currency but it is on the way to euro introduction. Regarding the experiences from the beginning of the 1990s when Croatia was faced with serious monetary instabilities and hyperinflation, the goal of Croatian National Bank (CNB is to ensure price stability and one way to do so is through exchange rate policy. Croatia, as a small and open economy, has applied a managed floating exchange rate regime. The exchange rate is determined primarily by the foreign exchange supply and demand on the foreign exchange market, with occasional market interventions by the CNB. Therefore, in order to maintain exchange rate stability, policymakers must be able to recognize how changes in these factors affect changes in the exchange rate. This research aims to find a relationship among the main sources of foreign currency inflow and outflow and the level of exchange rate in Croatia. The analysis is carried out by using the bounds testing (ARDL approach for co-integration. The results indicate the existence of a stable co-integration relationship between the observed variables, whereby an increase in the majority of variables leads to an exchange rate appreciation.

  13. Analyzing Influential Factors Against Timeliness of Financial Reporting (Empirical Study of Automation and Components and Telecommunication Companies Listed on Indonesia Stock Exchange.

    Directory of Open Access Journals (Sweden)

    Joko Suryanto


    Full Text Available This research aims to examine the effect of the relationship between firm size, profitability, solvency, public ownership, and the audit opinion on the timeliness of financial reporting. The dependent variable in the form of timekeeping company deliver the financial statements to the Stock Exchange. Meanwhile for the independent variables such as firm size measured by total asets of the company, profitability is measured by profit margin ratio, solvency measured by debt-to-equity ratio, public ownership is measured by the percentage of the number of shares owned by the community, and the audit opinion is measured with an unqualified opinion and otherwise unqualified. This study uses secondary data with population automotive companies and telecommunications components and annual financial statements issued on the Stock Exchange in the period 2010-2012. From the analysis conducted in this study it can be concluded that the size of the company significantly influence the timeliness of financial reporting. While profitability, solvency, public ownership, and the audit opinion does not affect the timeliness of financial reporting.

  14. Sorting Nexin 27 Protein Regulates Trafficking of a p21-activated Kinase (PAK) Interacting Exchange Factor (β-Pix)-G Protein-coupled Receptor Kinase Interacting Protein (GIT) Complex via a PDZ Domain Interaction* (United States)

    Valdes, Julie L.; Tang, Jingrong; McDermott, Mark I.; Kuo, Jean-Cheng; Zimmerman, Seth P.; Wincovitch, Stephen M.; Waterman, Clare M.; Milgram, Sharon L.; Playford, Martin P.


    Sorting nexin 27 (SNX27) is a 62-kDa protein localized to early endosomes and known to regulate the intracellular trafficking of ion channels and receptors. In addition to a PX domain, SNX27 is the only sorting family member that contains a PDZ domain. To identify novel SNX27-PDZ binding partners, we performed a proteomic screen in mouse principal kidney cortical collecting duct cells using a GST-SNX27 fusion construct as bait. We found that β-Pix (p21-activated kinase-interactive exchange factor), a guanine nucleotide exchange factor for the Rho family of small GTPases known to regulate cell motility directly interacted with SNX27. The association of β-Pix and SNX27 is specific for β-Pix isoforms terminating in the type-1 PDZ binding motif (ETNL). In the same screen we also identified Git1/2 as a potential SNX27 interacting protein. The interaction between SNX27 and Git1/2 is indirect and mediated by β-Pix. Furthermore, we show recruitment of the β-Pix·Git complex to endosomal sites in a SNX27-dependent manner. Finally, migration assays revealed that depletion of SNX27 from HeLa and mouse principal kidney cortical collecting duct cells significantly decreases cell motility. We propose a model by which SNX27 regulates trafficking of β-Pix to focal adhesions and thereby influences cell motility. PMID:21926430

  15. Exchange potentials of phosphorus between sediments and water coupled to alkaline phosphatase activity and environmental factors in an oligo-mesotrophic reservoir. (United States)

    Mhamdi, Badre Alaoui; Azzouzi, Assia; Elloumi, Jannet; Ayadi, Habib; Mhamdi, Mohammed Alaoui; Aleya, Lotfi


    We investigated the exchange potentials of phosphates at the water-sediment interface together with in situ benthic-chamber fractionated alkaline phosphatase activity and bacteria estimates during September and October 1998 at two stations: station 1, which received immediately the urban inputs from the Taounate city, and station 2, located in the centre of the Sahela reservoir (Morocco). The results showed that low oxygenation enhanced both the bacterial abundance and the alkaline phosphatase activity. Size-fractionated (0.65-100 microm) bacteria attached to dead organic matter together with algae and zooplankton contributed strongly (78%) to the total alkaline phosphatase synthesis in the two sampled stations, suggesting that attachment to organic particles stimulated phosphatase activities. The appearance of anoxic conditions and the decrease of pH supported the dissolution of particulate phosphorus and the release of soluble reactive phosphorus. This latter, together with persisting discharges of organic matter, sewage, and olive mill waste will exacerbate the eutrophication of the reservoir.

  16. VT Telephone Exchange Boundaries (United States)

    Vermont Center for Geographic Information — (Link to Metadata) The UtilityTelecom_EXCHANGE represents Vermont Telephone Exchange boundaries as defined by the VT Public Service Board. The original data was...

  17. Ideal Heat Exchange System (United States)

    Tsirlin, A. M.


    The requirements with which a heat exchange system should comply in order that at certain values of the total contact surface and heat load the entropy production in it should be minimal have been determined. It has been shown that this system can serve as a standard for real systems of irreversible heat exchange. We have found the conditions for physical realizability of a heat exchange system in which heat exchange occurs by a law linear with respect to the temperature difference between contacting flows. Analogous conditions are given without deriving for the case of heat exchange by the Fourier law.

  18. Resolution exchange simulation. (United States)

    Lyman, Edward; Ytreberg, F Marty; Zuckerman, Daniel M


    We extend replica-exchange simulation in two ways and apply our approaches to biomolecules. The first generalization permits exchange simulation between models of differing resolution--i.e., between detailed and coarse-grained models. Such "resolution exchange" can be applied to molecular systems or spin systems. The second extension is to "pseudoexchange" simulations, which require little CPU usage for most levels of the exchange ladder and also substantially reduce the need for overlap between levels. Pseudoexchanges can be used in either replica or resolution exchange simulations. We perform efficient, converged simulations of a 50-atom peptide to illustrate the new approaches.

  19. Ammonium removal from aqueous solution by ion-exchange using ...

    African Journals Online (AJOL)

    Ammonium removal from aqueous solution by a natural ion-exchange resin was investigated by considering the factors affecting the ammonium-exchange capacity including the zeolites' particle size, the loading flow rates and the impact of a number of regenerations upon the ion-exchange capacity. The resin column was ...

  20. A Range-Based Multivariate Model for Exchange Rate Volatility

    NARCIS (Netherlands)

    B. Tims (Ben); R.J. Mahieu (Ronald)


    textabstractIn this paper we present a parsimonious multivariate model for exchange rate volatilities based on logarithmic high-low ranges of daily exchange rates. The multivariate stochastic volatility model divides the log range of each exchange rate into two independent latent factors, which are

  1. Health information exchange among US hospitals. (United States)

    Adler-Milstein, Julia; DesRoches, Catherine M; Jha, Ashish K


    To determine the proportion of US hospitals engaged in health information exchange (HIE) with unaffiliated providers and to identify key hospital-level and market-level factors associated with participating in exchange. Using the 2009 American Hospital Association Information Technology survey, supplemented by Dartmouth Atlas, Area Resource File, and other national data, we examined which hospitals participated in regional efforts to electronically exchange clinical data. We used logistic regression models to determine hospital-level characteristics and market-level characteristics associated with hospitals' likelihood of participating in HIE. We found that 10.7% of US hospitals engaged in HIE with unaffiliated providers. In communities where exchange occurred, for-profit hospitals and those with a small market share were far less likely to engage in HIE than nonprofit hospitals or those with a larger market share. Hospitals in more concentrated markets were more likely to exchange and hospitals in markets with higher Medicare spending were less likely to exchange. At the start of implementation of the Health Information Technology for Economic and Clinical Health (HITECH) Act, only a small minority of US hospitals electronically exchange clinical data with unaffiliated providers. Health information exchange is a key part of reforming the healthcare system, and factors related to competitiveness may be holding some providers back.

  2. cAMP Signaling of Adenylate Cyclase Toxin Blocks the Oxidative Burst of Neutrophils through Epac-Mediated Inhibition of Phospholipase C Activity

    Czech Academy of Sciences Publication Activity Database

    Černý, Ondřej; Anderson, K.E.; Stephens, L.R.; Hawkins, P.T.; Šebo, Peter


    Roč. 198, č. 3 (2017), s. 1285-1296 ISSN 0022-1767 R&D Projects: GA ČR(CZ) GA13-14547S; GA MŠk(CZ) LM2015064 Institutional support: RVO:61388971 Keywords : BORDETELLA-PERTUSSIS * NADPH OXIDASE * CYCLIC-AMP Subject RIV: EE - Microbiology, Virology Impact factor: 4.856, year: 2016

  3. Coordinated regulation by two VPS9 domain-containing guanine nucleotide exchange factors in small GTPase Rab5 signaling pathways in fission yeast

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, Yuta [Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan); Kagiwada, Satoshi [Department of Biological Sciences, Faculty of Science, Nara Women' s University, Kitauoyanishi-machi, Nara 630-8506 (Japan); Shimazu, Sayuri [Center for Supports to Research and Education Activities, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan); Takegawa, Kaoru [Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Noguchi, Tetsuko [Department of Biological Sciences, Faculty of Science, Nara Women' s University, Kitauoyanishi-machi, Nara 630-8506 (Japan); Miyamoto, Masaaki, E-mail: [Department of Biology, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan); Center for Supports to Research and Education Activities, Kobe University, 1-1 Rokkodai-cho, Nada, Kobe 657-8501 (Japan)


    The small GTPase Rab5 is reported to regulate various cellular functions, such as vesicular transport and endocytosis. VPS9 domain-containing proteins are thought to activate Rab5(s) by their guanine-nucleotide exchange activities. Numerous VPS9 proteins have been identified and are structurally conserved from yeast to mammalian cells. However, the functional relationships among VPS9 proteins in cells remain unclear. Only one Rab5 and two VPS9 proteins were identified in the Schizosaccharomyces pombe genome. Here, we examined the cellular function of two VPS9 proteins and the relationship between these proteins in cellular functions. Vps901-GFP and Vps902-GFP exhibited dotted signals in vegetative and differentiated cells. vps901 deletion mutant (Δvps901) cells exhibited a phenotype deficient in the mating process and responses to high concentrations of ions, such as calcium and metals, and Δvps901Δvps902 double mutant cells exhibited round cell shapes similar to ypt5-909 (Rab5 mutant allele) cells. Deletion of both vps901 and vps902 genes completely abolished the mating process and responses to various stresses. A lack of vacuole formation and aberrant inner cell membrane structures were also observed in Δvps901Δvps902 cells by electron microscopy. These data strongly suggest that Vps901 and Vps902 are cooperatively involved in the regulation of cellular functions, such as cell morphology, sexual development, response to ion stresses, and vacuole formation, via Rab5 signaling pathways in fission yeast cells. - Highlights: • Roles of Rab5 activator VPS9 proteins in cellular functions. • Cooperation between VPS9 proteins in Rab5 signaling pathway. • Roles of each VPS9 protein in Rab5 signaling pathway are discussed.

  4. Factors Associated With Medical School Entrants' Interest in Military Financial Assistance in Exchange for a Service Obligation: The Michigan State University College of Human Medicine Cohort. (United States)

    Sienko, Dean G; Oberst, Kathleen


    The U.S. military offers comprehensive scholarships to medical students to help offset costs in exchange for either reserve or active duty service commitments. Our goal was to describe to what degree newly admitted students to Michigan State University's College of Human Medicine were aware of and interested in these opportunities. We surveyed 176 newly admitted students at the beginning and immediately following a presentation on military medicine opportunities. We collected anonymous paper surveys from program attendees and entered the data into Stata v13.1. The project was submitted for institutional review board review and deemed to not involve human subjects. Tests of association were performed using Chi-square test of independence and Fisher's exact test where needed. Our cohort was 49% female, 51% male, and over 90% were less than 30 years of age. Only 14% reported having family involved in the military. Our results indicated that over 90% of students were aware of these programs but less than 3% took advantage of the offerings. Despite 65% reporting somewhat or significant concerns over debt, financial concerns were not statistically associated with scholarship interest level. Instead, having a family member in the military was the most significant positive predictor of interest (47% compared with 17%, p service aside from financial support. Career vignettes and summaries may offer better insight into the service experience for those lacking familiarity thereby potentially increasing interest and applications. Focus groups with current scholarship awardees may inform recruitment strategies. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

  5. [Effect of space flight factors simulated in ground-based experiments on the behavior, discriminant learning, and exchange of monoamines in different brain structures of rats]. (United States)

    Shtemberg, A S; Lebedeva-Georgievskaia, K V; Matveeva, M I; Kudrin, V S; Narkevich, V B; Klodt, P M; Bazian, A S


    Experimental treatment (long-term fractionated γ-irradiation, antiorthostatic hypodynamia, and the combination of these factors) simulating the effect of space flight in ground-based experiments rapidly restored the motor and orienting-investigative activity of animals (rats) in "open-field" tests. The study of the dynamics of discriminant learning of rats of experimental groups did not show significant differences from the control animals. It was found that the minor effect of these factors on the cognitive performance of animals correlated with slight changes in the concentration ofmonoamines in the brain structures responsible for the cognitive, emotional, and motivational functions.


    Directory of Open Access Journals (Sweden)



    Full Text Available Moderate fluctuation of the exchange rate, basically in its floating regime is considered normality. Meanwhile,excessive volatility of the exchange rate is an issue for many countries. Its elimination is directed to foreign trade, which, through essential exports, followed by significant currency inflows, contribute to the stability of exchange rates. Unfortunately, Moldova’s foreign trade has become a key factor in maintaining the stability of foreign exchange.

  7. Foreign Exchange Reserves: Bangladesh Perspective

    Directory of Open Access Journals (Sweden)

    Md Zahangir Alam


    Full Text Available This study is about foreign exchangereserves of Bangladesh. The mainpurpose of this study is to the influence of exchange rates on foreign exchangereserves to the Bangladesh context.  Both the primary and secondary data has been used inthis study. The primary data has been collected through a structuredquestionnaire from 50 respondents. The secondary data, namely Bangladeshforeign exchange reserves (FER, Bangladesh current account balance (CAB,Bangladesh capital andfinancial account balance (CFAB, and BDT/USD exchange rates (ER.  This study covers yearly data from July 01,1996 to June 30, 2005 and quarterly data from July 01, 2005 to June 30, 2012. Findingsof this study shows that out of the selected 16 factors affecting foreignexchange reserves, exchange rates occupy the first position, weighted averagescore (WAS being 4.56. Foreign exchange reserves (FER and current accountbalance (CAB have increased by 502.9087% and 1451.218%,whereas capital and financial account (CFAB has decreased by -649.024% on June30, 2012 compared to June 30, 1997. The influence of other factors heldconstant, as ER changes by 285.6894 units due to one unit change in FER, onaverage in the same direction which represents that ER has positive effect on theFER and this relationship is statistically significant.  62.1526 percentof the variation in FER is explained by ER. The outcomes of Breusch-Godfrey test (LM test, ARCHtest, and the Normality test are that there is a serial correlation among residuals, the variance of residuals is notconstant, and the residuals are not normally distributed.

  8. Adaptively Compressed Exchange Operator

    CERN Document Server

    Lin, Lin


    The Fock exchange operator plays a central role in modern quantum chemistry. The large computational cost associated with the Fock exchange operator hinders Hartree-Fock calculations and Kohn-Sham density functional theory calculations with hybrid exchange-correlation functionals, even for systems consisting of hundreds of atoms. We develop the adaptively compressed exchange operator (ACE) formulation, which greatly reduces the computational cost associated with the Fock exchange operator without loss of accuracy. The ACE formulation does not depend on the size of the band gap, and thus can be applied to insulating, semiconducting as well as metallic systems. In an iterative framework for solving Hartree-Fock-like systems, the ACE formulation only requires moderate modification of the code, and can be potentially beneficial for all electronic structure software packages involving exchange calculations. Numerical results indicate that the ACE formulation can become advantageous even for small systems with tens...

  9. Laser Processed Heat Exchangers (United States)

    Hansen, Scott


    The Laser Processed Heat Exchanger project will investigate the use of laser processed surfaces to reduce mass and volume in liquid/liquid heat exchangers as well as the replacement of the harmful and problematic coatings of the Condensing Heat Exchangers (CHX). For this project, two scale unit test articles will be designed, manufactured, and tested. These two units are a high efficiency liquid/liquid HX and a high reliability CHX.

  10. Microsoft Exchange 2013 cookbook

    CERN Document Server

    Van Horenbeeck, Michael


    This book is a practical, hands-on guide that provides the reader with a number of clear, step-by-step exercises.""Microsoft Exchange 2013 Cookbook"" is targeted at network administrators who deal with the Exchange server in their day-to-day jobs. It assumes you have some practical experience with previous versions of Exchange (although this is not a requirement), without being a subject matter expert.

  11. Microtube strip heat exchanger (United States)

    Doty, F. D.


    During the last quarter, Doty Scientific, Inc. (DSI) continued to make progress on the microtube strip (MTS) heat exchanger. The DSI completed a heat exchanger stress analysis of the ten-module heat exchanger bank; and performed a shell-side flow inhomogeneity analysis of the three-module heat exchanger bank. The company produced 50 tubestrips using an in-house CNC milling machine and began pressing them onto tube arrays. The DSI revised some of the tooling required to encapsulate a tube array and press tubestrips into the array to improve some of the prototype tooling.

  12. GRUNDTVIG in transnational exchange

    DEFF Research Database (Denmark)

    Grundtvig in transnational exchange is the report from the seminar in december 2015 in cooperation with University of Cape Town and University of Hamburg.......Grundtvig in transnational exchange is the report from the seminar in december 2015 in cooperation with University of Cape Town and University of Hamburg....

  13. Optimization of Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Ivan Catton


    The objective of this research is to develop tools to design and optimize heat exchangers (HE) and compact heat exchangers (CHE) for intermediate loop heat transport systems found in the very high temperature reator (VHTR) and other Generation IV designs by addressing heat transfer surface augmentation and conjugate modeling. To optimize heat exchanger, a fast running model must be created that will allow for multiple designs to be compared quickly. To model a heat exchanger, volume averaging theory, VAT, is used. VAT allows for the conservation of mass, momentum and energy to be solved for point by point in a 3 dimensional computer model of a heat exchanger. The end product of this project is a computer code that can predict an optimal configuration for a heat exchanger given only a few constraints (input fluids, size, cost, etc.). As VAT computer code can be used to model characteristics )pumping power, temperatures, and cost) of heat exchangers more quickly than traditional CFD or experiment, optimization of every geometric parameter simultaneously can be made. Using design of experiment, DOE and genetric algorithms, GE, to optimize the results of the computer code will improve heat exchanger disign.

  14. Education and Industry Exchange (United States)

    Webb, Gerald A.


    Through an exchange plan a school representative worked at the personnel counter of a local company, and a supervisor from that company worked with counselors, faculty, administrators, and students from the local school. The exchange of ideas and insights were of benefit to the school and the company. (KP)

  15. İşletmelerde Bir Avantaj Unsuru Olarak Kur Korelasyonlarının Kullanımı(Using Exchange Rate Correlation as An Advantage Factor in Managements

    Directory of Open Access Journals (Sweden)

    Cantürk KAYAHAN


    Full Text Available Today, international competition is not only based on production of technology and product, but also requires use of some financial advantages. Exchange rate correlations one of these advantages allow the financial managers to understand how exchange rates change and to follow portfolio risks better. Some exchange rates may change the same way, while the others may change opposite way. In this study, the effect of exchange rate correlations over a sample portfolio is analyzed and their possible advantages or disadvantages over firms are evaluated.

  16. A cross-country Exchange Market Pressure (EMP) dataset. (United States)

    Desai, Mohit; Patnaik, Ila; Felman, Joshua; Shah, Ajay


    The data presented in this article are related to the research article titled - "An exchange market pressure measure for cross country analysis" (Patnaik et al. [1]). In this article, we present the dataset for Exchange Market Pressure values (EMP) for 139 countries along with their conversion factors, ρ (rho). Exchange Market Pressure, expressed in percentage change in exchange rate, measures the change in exchange rate that would have taken place had the central bank not intervened. The conversion factor ρ can interpreted as the change in exchange rate associated with $1 billion of intervention. Estimates of conversion factor ρ allow us to calculate a monthly time series of EMP for 139 countries. Additionally, the dataset contains the 68% confidence interval (high and low values) for the point estimates of ρ's. Using the standard errors of estimates of ρ's, we obtain one sigma intervals around mean estimates of EMP values. These values are also reported in the dataset.

  17. Heat exchanger design handbook

    CERN Document Server

    Thulukkanam, Kuppan


    Completely revised and updated to reflect current advances in heat exchanger technology, Heat Exchanger Design Handbook, Second Edition includes enhanced figures and thermal effectiveness charts, tables, new chapter, and additional topics--all while keeping the qualities that made the first edition a centerpiece of information for practicing engineers, research, engineers, academicians, designers, and manufacturers involved in heat exchange between two or more fluids.See What's New in the Second Edition: Updated information on pressure vessel codes, manufacturer's association standards A new c

  18. Anion exchange membrane (United States)

    Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus


    An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

  19. Data Exchange Inventory System (DEXI) (United States)

    Social Security Administration — Enterprise tool used to identify data exchanges occurring between SSA and our trading partners. DEXI contains information on both incoming and outgoing exchanges and...

  20. Microplate Heat Exchanger Project (United States)

    National Aeronautics and Space Administration — We propose a microplate heat exchanger for cryogenic cooling systems used for continuous flow distributed cooling systems, large focal plane arrays, multiple cooling...

  1. Exchange Risk Management Policy

    CERN Document Server


    At the Finance Committee of March 2005, following a comment by the CERN Audit Committee, the Chairman invited the Management to prepare a document on exchange risk management policy. The Finance Committee is invited to take note of this document.

  2. HUD Exchange Grantee Database (United States)

    Department of Housing and Urban Development — The About Grantees section of the HUD Exchange brings up contact information, reports, award, jurisdiction, and location data for organizations that receive HUD...

  3. NASA Earth Exchange (NEX) (United States)

    National Aeronautics and Space Administration — The NASA Earth Exchange (NEX) represents a new platform for the Earth science community that provides a mechanism for scientific collaboration and knowledge sharing....

  4. Anion exchange polymer electrolytes (United States)

    Kim, Yu Seung; Kim, Dae Sik


    Anion exchange polymer electrolytes that include guanidinium functionalized polymers may be used as membranes and binders for electrocatalysts in preparation of anodes for electrochemical cells such as solid alkaline fuel cells.

  5. Rapgef2, a guanine nucleotide exchange factor for Rap1 small GTPases, plays a crucial role in adherence junction (AJ) formation in radial glial cells through ERK-mediated upregulation of the AJ-constituent protein expression. (United States)

    Farag, Maged Ibrahim; Yoshikawa, Yoko; Maeta, Kazuhiro; Kataoka, Tohru


    Rapgef2 and Rapgef6 define a subfamily of guanine nucleotide exchange factors for Rap1, characterized by possession of the Ras/Rap-associating domains and implicated in the etiology of schizophrenia. We previously found that dorsal telencephalon-specific Rapgef2 conditional knockout mice exhibits severe defects in formation of apical surface adherence junctions (AJs) and localization of radial glial cells (RGCs). In this study, we analyze the underlying molecular mechanism by using primary cultures of RGCs established from the developing cerebral cortex. The results show that Rapgef2-deficient RGCs exhibit a decreased ability of neurosphere formation, morphological changes represented by regression of radial glial (RG) fibers and reduced expression of AJ-constituent proteins such as N-cadherin, zonula occludens-1, E-cadherin and β-catenin. Moreover, siRNA-mediated knockdown of Rapgef2 or Rap1A inhibits the AJ protein expression and RG fiber formation while overexpression of Rapgef2, Rapgef6, Rap1AG12V or Rap1BG12V in Rapgef2-deficient RGCs restores them. Furthermore, Rapgef2-deficient RGCs exhibit a reduction in phosphorylation of extracellular signal-regulated kinase (ERK) leading to downregulation of the expression of c-jun, which is implicated in the AJ protein expression. These results indicate a crucial role of the Rapgef2-Rap1A-ERK-c-jun pathway in regulation of the AJ formation in RGCs. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Cryptographic Combinatorial Securities Exchanges (United States)

    Thorpe, Christopher; Parkes, David C.

    We present a useful new mechanism that facilitates the atomic exchange of many large baskets of securities in a combinatorial exchange. Cryptography prevents information about the securities in the baskets from being exploited, enhancing trust. Our exchange offers institutions who wish to trade large positions a new alternative to existing methods of block trading: they can reduce transaction costs by taking advantage of other institutions’ available liquidity, while third party liquidity providers guarantee execution—preserving their desired portfolio composition at all times. In our exchange, institutions submit encrypted orders which are crossed, leaving a “remainder”. The exchange proves facts about the portfolio risk of this remainder to third party liquidity providers without revealing the securities in the remainder, the knowledge of which could also be exploited. The third parties learn either (depending on the setting) the portfolio risk parameters of the remainder itself, or how their own portfolio risk would change if they were to incorporate the remainder into a portfolio they submit. In one setting, these third parties submit bids on the commission, and the winner supplies necessary liquidity for the entire exchange to clear. This guaranteed clearing, coupled with external price discovery from the primary markets for the securities, sidesteps difficult combinatorial optimization problems. This latter method of proving how taking on the remainder would change risk parameters of one’s own portfolio, without revealing the remainder’s contents or its own risk parameters, is a useful protocol of independent interest.

  7. Exchanging Description Logic Knowledge Bases

    NARCIS (Netherlands)

    Arenas, M.; Botoeva, E.; Calvanese, D.; Ryzhikov, V.; Sherkhonov, E.


    In this paper, we study the problem of exchanging knowledge between a source and a target knowledge base (KB), connected through mappings. Differently from the traditional database exchange setting, which considers only the exchange of data, we are interested in exchanging implicit knowledge. As

  8. Microgravity condensing heat exchanger (United States)

    Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor); North, Andrew (Inventor); Weislogel, Mark M. (Inventor)


    A heat exchanger having a plurality of heat exchanging aluminum fins with hydrophilic condensing surfaces which are stacked and clamped between two cold plates. The cold plates are aligned radially along a plane extending through the axis of a cylindrical duct and hold the stacked and clamped portions of the heat exchanging fins along the axis of the cylindrical duct. The fins extend outwardly from the clamped portions along approximately radial planes. The spacing between fins is symmetric about the cold plates, and are somewhat more closely spaced as the angle they make with the cold plates approaches Passageways extend through the fins between vertex spaces which provide capillary storage and communicate with passageways formed in the stacked and clamped portions of the fins, which communicate with water drains connected to a pump externally to the duct. Water with no entrained air is drawn from the capillary spaces.

  9. Ion exchange phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Bourg, I.C.; Sposito, G.


    Ion exchange phenomena involve the population of readily exchangeable ions, the subset of adsorbed solutes that balance the intrinsic surface charge and can be readily replaced by major background electrolyte ions (Sposito, 2008). These phenomena have occupied a central place in soil chemistry research since Way (1850) first showed that potassium uptake by soils resulted in the release of an equal quantity of moles of charge of calcium and magnesium. Ion exchange phenomena are now routinely modeled in studies of soil formation (White et al., 2005), soil reclamation (Kopittke et al., 2006), soil fertilitization (Agbenin and Yakubu, 2006), colloidal dispersion/flocculation (Charlet and Tournassat, 2005), the mechanics of argillaceous media (Gajo and Loret, 2007), aquitard pore water chemistry (Tournassat et al., 2008), and groundwater (Timms and Hendry, 2007; McNab et al., 2009) and contaminant hydrology (Chatterjee et al., 2008; van Oploo et al., 2008; Serrano et al., 2009).


    African Journals Online (AJOL)

    Common stock value is affected by two important economic and financial risk factors namely interest rate and exchange rate. Interest rate which reflects the price of money also affects other variables in the financial market. Valuation of stock prices is indirectly affected by interest rates while directly its volatility causes a shift ...

  11. Modeling foreign exchange risk premium in Armenia

    NARCIS (Netherlands)

    Poghosyan, Tigran; Kocenda, Evnen; Zemcik, Petr


    This paper applies stochastic discount factor methodology to modeling the foreign exchange risk premium in Armenia. We use weekly data on foreign and domestic currency deposits, which coexist in the Armenian banking system. This coexistence implies elimination of the cross-country risks and

  12. Recent Gene Duplication and Subfunctionalization Produced a Mitochondrial GrpE, the Nucleotide Exchange Factor of the Hsp70 Complex, Specialized in Thermotolerance to Chronic Heat Stress in Arabidopsis1[W][OA (United States)

    Hu, Catherine; Lin, Siou-ying; Chi, Wen-tzu; Charng, Yee-yung


    The duplication and divergence of heat stress (HS) response genes might help plants adapt to varied HS conditions, but little is known on the topic. Here, we examined the evolution and function of Arabidopsis (Arabidopsis thaliana) mitochondrial GrpE (Mge) proteins. GrpE acts as a nucleotide-exchange factor in the Hsp70/DnaK chaperone machinery. Genomic data show that AtMge1 and AtMge2 arose from a recent whole-genome duplication event. Phylogenetic analysis indicated that duplication and preservation of Mges occurred independently in many plant species, which suggests a common tendency in the evolution of the genes. Intron retention contributed to the divergence of the protein structure of Mge paralogs in higher plants. In both Arabidopsis and tomato (Solanum lycopersicum), Mge1 is induced by ultraviolet B light and Mge2 is induced by heat, which suggests regulatory divergence of the genes. Consistently, AtMge2 but not AtMge1 is under the control of HsfA1, the master regulator of the HS response. Heterologous expression of AtMge2 but not AtMge1 in the temperature-sensitive Escherichia coli grpE mutant restored its growth at 43°C. Arabidopsis T-DNA knockout lines under different HS regimes revealed that Mge2 is specifically required for tolerating prolonged exposure to moderately high temperature, as compared with the need of the heat shock protein 101 and the HS-associated 32-kD protein for short-term extreme heat. Therefore, with duplication and subfunctionalization, one copy of the Arabidopsis Mge genes became specialized in a distinct type of HS. We provide direct evidence supporting the connection between gene duplication and adaptation to environmental stress. PMID:22128139

  13. Heat exchanger panel (United States)

    Warburton, Robert E. (Inventor); Cuva, William J. (Inventor)


    The present invention relates to a heat exchanger panel which has broad utility in high temperature environments. The heat exchanger panel has a first panel, a second panel, and at least one fluid containment device positioned intermediate the first and second panels. At least one of the first panel and the second panel have at least one feature on an interior surface to accommodate the at least one fluid containment device. In a preferred embodiment, each of the first and second panels is formed from a high conductivity, high temperature composite material. Also, in a preferred embodiment, the first and second panels are joined together by one or more composite fasteners.

  14. Microscale Regenerative Heat Exchanger (United States)

    Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred


    The device described herein is designed primarily for use as a regenerative heat exchanger in a miniature Stirling engine or Stirling-cycle heat pump. A regenerative heat exchanger (sometimes called, simply, a "regenerator" in the Stirling-engine art) is basically a thermal capacitor: Its role in the Stirling cycle is to alternately accept heat from, then deliver heat to, an oscillating flow of a working fluid between compression and expansion volumes, without introducing an excessive pressure drop. These volumes are at different temperatures, and conduction of heat between these volumes is undesirable because it reduces the energy-conversion efficiency of the Stirling cycle.

  15. Climate control of terrestrial carbon exchange across biomes and continents

    DEFF Research Database (Denmark)

    Yi, Chuixiang; Ricciuto, Daniel; Li, Runze


    climate and terrestrial CO2 exchange with the atmosphere across biomes and continents are lacking. Here we present data describing the relationships between net ecosystem exchange of carbon (NEE) and climate factors as measured using the eddy covariance method at 125 unique sites in various ecosystems...

  16. Exchange rates, petroleum prices and price determination in Sierra ...

    African Journals Online (AJOL)

    This study determined the effects of monetary environment, exchange rate movement and petroleum prices on domestic prices in Sierra Leone by estimating a hybrid model of inflation. The empirical results showed that petroleum product prices, exchange rate as well as monetary factors determined inflation in Sierra Leone ...

  17. Operating revenue changes in a demutualized stock exchange

    Directory of Open Access Journals (Sweden)

    Mohamed Hesham Abdel-Hafez


    Full Text Available Stock exchanges were traditionally run as cooperative venues. The globalization, the development of technology, and the increase of competition among stock exchanges forced these venues to change their structure and adopt a new one-demutualization- that can be a lifeline in facing these environmental changes in regards to stock exchanges. This new trend enables the exchange to expand their activities and supply the market with new products and services, therefore enhancing the value of the exchange itself. The main sources of revenue for traditional exchanges have been listing fees, transaction fees, membership fees and the sale of information services such as market data, quotations, and trade data. Due to the environmental changes the stock exchanges' services are now executed electronically, and in turn, this has led to an increase in the competition among exchanges. Furthermore, this increased competition has led to the re-adjustment of the regulation structure which gradually erodes the sources of revenues provided by the conventional stock exchanges. The paper divided the research plan into two sections: the first section is to highlight the concept of demutualization process; the phases of demutualization, the factors that push the stock exchanges to demutualize and the benefits of demutualization. The second section was based on statistical comparative analysis of the stock exchanges' revenues prior and after demutualization. The researcher used the regression analysis tool on seven demutualized stock exchanges during the period from 1997-2012. The paper aims to prove that demutualization has a positive effect on the revenues of the stock exchange, thus it enhances the value of the exchange.

  18. Nature's Heat Exchangers. (United States)

    Barnes, George


    Discusses the heat-transfer systems of different animals. Systems include heat conduction into the ground, heat transferred by convection, heat exchange in lizards, fish and polar animals, the carotid rete system, electromagnetic radiation from animals and people, and plant and animal fiber optics. (MDH)

  19. Basic Exchange Rate Theories

    NARCIS (Netherlands)

    J.G.M. van Marrewijk (Charles)


    textabstractThis four-chapter overview of basic exchange rate theories discusses (i) the elasticity and absorption approach, (ii) the (long-run) implications of the monetary approach, (iii) the short-run effects of monetary and fiscal policy under various economic conditions, and (iv) the transition

  20. Technology Performance Exchange

    Energy Technology Data Exchange (ETDEWEB)


    To address the need for accessible, high-quality data, the Department of Energy has developed the Technology Performance Exchange (TPEx). TPEx enables technology suppliers, third-party testing laboratories, and other entities to share product performance data. These data are automatically transformed into a format that technology evaluators can easily use in their energy modeling assessments to inform procurement decisions.

  1. Telephone Exchange Maintenance

    CERN Document Server


    Urgent maintenance work on CERN telephone exchanges will be performed on 24 March from 6 a.m. to 8 a.m. Telephone services may be disrupted or even interrupted during this time. For more details, please contact us by email at

  2. Baltic Exchange toodi Tallinna

    Index Scriptorium Estoniae


    Viimane osa merekonteineritesse kokkupakitud Londoni laevandus- ja merebörsi Baltic Exchange'i endise peakorteri detailidest jõudis 2007. a. juunis Tallinna. Hoone detailid ostnud ärimehed Heiti Hääl ja Eerik-Niiles Kross plaanivad leida hoonele koha Tallinna kesklinnas. E.-N. Krossi kommentaar

  3. Heat exchanger. Varmeveksler

    Energy Technology Data Exchange (ETDEWEB)

    Rosman, I.E.; Wagner, W.R.


    The invention concerns a manifold for a plate-type heat exchanger, and includes a side channel connected the inlet of the manifold. The plates can be designed as an integral assembly together with the integrated side- and external end-manifolds as well. 16 drawings.

  4. Chemical exchange program analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Waffelaert, Pascale


    As part of its EMS, Sandia performs an annual environmental aspects/impacts analysis. The purpose of this analysis is to identify the environmental aspects associated with Sandia's activities, products, and services and the potential environmental impacts associated with those aspects. Division and environmental programs established objectives and targets based on the environmental aspects associated with their operations. In 2007 the most significant aspect identified was Hazardous Materials (Use and Storage). The objective for Hazardous Materials (Use and Storage) was to improve chemical handling, storage, and on-site movement of hazardous materials. One of the targets supporting this objective was to develop an effective chemical exchange program, making a business case for it in FY07, and fully implementing a comprehensive chemical exchange program in FY08. A Chemical Exchange Program (CEP) team was formed to implement this target. The team consists of representatives from the Chemical Information System (CIS), Pollution Prevention (P2), the HWMF, Procurement and the Environmental Management System (EMS). The CEP Team performed benchmarking and conducted a life-cycle analysis of the current management of chemicals at SNL/NM and compared it to Chemical Exchange alternatives. Those alternatives are as follows: (1) Revive the 'Virtual' Chemical Exchange Program; (2) Re-implement a 'Physical' Chemical Exchange Program using a Chemical Information System; and (3) Transition to a Chemical Management Services System. The analysis and benchmarking study shows that the present management of chemicals at SNL/NM is significantly disjointed and a life-cycle or 'Cradle-to-Grave' approach to chemical management is needed. This approach must consider the purchasing and maintenance costs as well as the cost of ultimate disposal of the chemicals and materials. A chemical exchange is needed as a mechanism to re-apply chemicals on site. This

  5. Hard Colour Singlet Exchange at the Tevatron

    CERN Document Server

    Cox, Brian; Lonnblad, Leif; Cox, Brian; Forshaw, Jeff; Lonnblad, Leif


    We have performed a detailed phenomenological investigation of the hard colour singlet exchange process which is observed at the Tevatron in events which have a large rapidity gap between outgoing jets. We include the effects of multiple interactions to obtain a prediction for the gap survival factor. Comparing the data on the fraction of gap events with the prediction from BFKL pomeron exchange we find agreement provided that a constant value of alpha_s is used in the BFKL calculation. Moreover, the value of alpha_s is in line with that extracted from measurements made at HERA.

  6. [Eco-physiological investigations on wild and cultivated plants in the Negev Desert : II. The influence of climatic factors on carbon dioxide exchange and transpiration at the end of the dry period]. (United States)

    Schulze, E -D; Lange, O L; Koch, W


    The influence of climatic factors on net photosynthesis, dark respiration and transpiration was investigated in the Negev Desert at the end of the dry summer period when plant water stress was at a maximum. Species studied included: dominant species of the natural vegetation (Artemisia herba-alba, Hammada scoparia, Noaea mucronata, Reaumuria negevensis, Salsola inermis, Zygophyllum dumosum), cultivated plants receiving rainfall and run-off water during the winter season in the run-off farm Avdat (Prunus armeniaca, Vitis vinifera), and irrigated cultivated plants receiving additional water during the summer season (Citrullus colocynthis, Datura metel). 1. Light saturation of net photosynthesis was reached at 60-90 klx conforming to the high solar radiation intensities of the desert. 2. Maximum rates of CO2 uptake per unit of dry weight for the irrigated mesomorphic plants was ten times that of the wild plants. However, in comparison to the other species, maximal rates of CO2 uptake for wild plants were higher when calculated on a leaf area basis than when represented on a dry weight basis. Maximum rates of net photosynthesis per unit chlorophyll content for some of the wild plants (Salsola and Noaea) were comparable to those of the cultivated Vitis and irrigated Citrullus and Datura, Hammada exhibited even higher rates than Prunus. This demonstrates the great photosynthetic capacity of the wild plants even at the end of the dry season. 3. The upper temperature compensation point for net photosynthesis of the wild plants was unusually high as an adaptation to the temperatures of the habitat. Compensation points higher than 49°C exceed the maxima known so far for other flowering species. Maximum rates of net photosynthesis of Hammada were measured when the temperature of the photosynthetic organs was 37°C; at 49°C photosynthesis was only reduced by 50%. 4. Leaf temperature affects plant gas exchange by influencing stomatal aperture. Diffusion resistance of leaves

  7. Analytical applications of ion exchangers

    CERN Document Server

    Inczédy, J


    Analytical Applications of Ion Exchangers presents the laboratory use of ion-exchange resins. This book discusses the development in the analytical application of ion exchangers. Organized into 10 chapters, this book begins with an overview of the history and significance of ion exchangers for technical purposes. This text then describes the properties of ion exchangers, which are large molecular water-insoluble polyelectrolytes having a cross-linked structure that contains ionic groups. Other chapters consider the theories concerning the operation of ion-exchange resins and investigate th


    Directory of Open Access Journals (Sweden)

    Attila Rozsa


    Full Text Available The profitability of the operation of an enterprise is influenced by several factors. Beside the evolution of market supply and demand the hectic changes in exchange rates have an increasingly important role too. Since the start of the economic crisis in the autumn of 2008, changes in the exchange rate have been more and more emphasized. The article deals with methods for decreasing exchange risks of foreign currency transactions, without the need of completeness. In international trade due to the growth of the number of currency loans the significance of managing financial risks coming from the changes in exchange rates has increased. One of the most obvious tools is properly selected currency.

  9. Extratropical Stratosphere-Troposphere Mass Exchange (United States)

    Schoeberl, Mark R.


    Understanding the exchange of gases between the stratosphere and the troposphere is important for determining how pollutants enter the stratosphere and how they leave. This study does a global analysis of that the exchange of mass between the stratosphere and the troposphere. While the exchange of mass is not the same as the exchange of constituents, you can t get the constituent exchange right if you have the mass exchange wrong. Thus this kind of calculation is an important test for models which also compute trace gas transport. In this study I computed the mass exchange for two assimilated data sets and a GCM. The models all agree that amount of mass descending from the stratosphere to the troposphere in the Northern Hemisphere extra tropics is approx. 10(exp 10) kg/s averaged over a year. The value for the Southern Hemisphere by about a factor of two. ( 10(exp 10) kg of air is the amount of air in 100 km x 100 km area with a depth of 100 m - roughly the size of the D.C. metro area to a depth of 300 feet.) Most people have the idea that most of the mass enters the stratosphere through the tropics. But this study shows that almost 5 times more mass enters the stratosphere through the extra-tropics. This mass, however, is quickly recycled out again. Thus the lower most stratosphere is a mixture of upper stratospheric air and tropospheric air. This is an important result for understanding the chemistry of the lower stratosphere.

  10. Data Exchange Inventory (DEXI) System (United States)

    Social Security Administration — DEXI is an intranet application used by SSA users to track all incoming and outgoing data exchanges between SSA and our data exchange partners. Information such as...

  11. Dynamical Clustering of Exchange Rates


    Fenn, Daniel J.; Porter, Mason A.; Mucha, Peter J; Mark McDonald; Stacy Williams; Johnson, Neil F.; Jones, Nick S


    We use techniques from network science to study correlations in the foreign exchange (FX) market over the period 1991--2008. We consider an FX market network in which each node represents an exchange rate and each weighted edge represents a time-dependent correlation between the rates. To provide insights into the clustering of the exchange rate time series, we investigate dynamic communities in the network. We show that there is a relationship between an exchange rate's functional role withi...

  12. Serial tempering without exchange. (United States)

    Nymeyer, Hugh


    Serial tempering is a computational method that turns the temperature T (or more generally any independent λ parameter) into a dynamical variable. It is shown that, under conditions for which this variable is fast, serial tempering is equivalent to the umbrella sampling method with a single effective potential. This equivalence is demonstrated using both a small one-dimensional system and a small solvated peptide. The suggestion is then made to replace the serial tempering protocol with the equivalent umbrella sampling calculation. This approach, serial tempering without exchange (STeWiE), has the same performance as serial tempering in the limit that exchanges are frequent, is simpler to implement, and has fewer adjustable parameters than conventional serial tempering. The equivalence of serial tempering and STeWiE also provides a convenient route for estimating and optimizing the performance of serial tempering simulations and other generalized-ensemble methods.

  13. Lipid exchange by ultracentrifugation

    DEFF Research Database (Denmark)

    Drachmann, Nikolaj Düring; Olesen, Claus


    Lipids play an important role in maintaining P-type ATPase structure and function, and often they are crucial for ATPase activity. When the P-type ATPases are in the membrane, they are surrounded by a mix of different lipids species with varying aliphatic chain lengths and saturation......, and the complex interplay between the lipids and the P-type ATPases are still not well understood. We here describe a robust method to exchange the majority of the lipids surrounding the ATPase after solubilisation and/or purification with a target lipid of interest. The method is based on an ultracentrifugation...... step, where the protein sample is spun through a dense buffer containing large excess of the target lipid, which results in an approximately 80-85 % lipid exchange. The method is a very gently technique that maintains protein folding during the process, hence allowing further characterization...

  14. Exchange rate rebounds after foreign exchange market interventions (United States)

    Hoshikawa, Takeshi


    This study examined the rebounds in the exchange rate after foreign exchange intervention. When intervention is strongly effective, the exchange rate rebounds at next day. The effect of intervention is reduced slightly by the rebound after the intervention. The exchange rate might have been 67.12-77.47 yen to a US dollar without yen-selling/dollar-purchasing intervention of 74,691,100 million yen implemented by the Japanese government since 1991, in comparison to the actual exchange rate was 103.19 yen to the US dollar at the end of March 2014.

  15. O3 and NOx Exchange

    NARCIS (Netherlands)

    Loubet, B.; Castell, J.F.; Laville, P.; Personne, E.; Tuzet, A.; Ammann, C.; Emberson, L.; Ganzeveld, L.; Kowalski, A.S.; Merbold, L.; Stella, P.; Tuovinen, J.P.


    This discussion was based on the background document “Review on modelling atmosphere-biosphere exchange of Ozone and Nitrogen oxides”, which reviews the processes contributing to biosphere-atmosphere exchange of O3 and NOx, including stomatal and non-stomatal exchange of O3 and NO, NO2.

  16. The stability of exchange networks

    NARCIS (Netherlands)

    Doğan, G.; Assen, M. van; Rijt, A. van de; Buskens, V.W.


    Economic and sociological exchange theories predict divisions of exchange benefits given an assumed fixed network of exchange relations. Since network structure has been found to have a large impact on actors’ payoffs, actors have strong incentives for network change.Weanswer the question what

  17. Integrated foreign exchange risk management

    DEFF Research Database (Denmark)

    Aabo, Tom; Høg, Esben; Kuhn, Jochen


    Empirical research has focused on export as a proxy for exchange rate exposure and the use of foreign exchange derivatives as an instrument to deal with this exposure. This empirical study applies an integrated foreign exchange risk management approach with a particular focus on the role of impor...

  18. Integrated Foreign Exchange Risk Management

    DEFF Research Database (Denmark)

    Aabo, Tom; Høg, Esben; Kuhn, Jochen

    Empirical research has focused on export as a proxy for the exchange rate exposure and the use of foreign exchange derivatives as the instrument to deal with this exposure. This empirical study applies an integrated foreign exchange risk management approach with a particular focus on the role...

  19. Scraped surface heat exchangers. (United States)

    Rao, Chetan S; Hartel, Richard W


    Scraped surface heat exchangers (SSHEs) are commonly used in the food, chemical, and pharmaceutical industries for heat transfer, crystallization, and other continuous processes. They are ideally suited for products that are viscous, sticky, that contain particulate matter, or that need some degree of crystallization. Since these characteristics describe a vast majority of processed foods, SSHEs are especially suited for pumpable food products. During operation, the product is brought in contact with a heat transfer surface that is rapidly and continuously scraped, thereby exposing the surface to the passage of untreated product. In addition to maintaining high and uniform heat exchange, the scraper blades also provide simultaneous mixing and agitation. Heat exchange for sticky and viscous foods such as heavy salad dressings, margarine, chocolate, peanut butter, fondant, ice cream, and shortenings is possible only by using SSHEs. High heat transfer coefficients are achieved because the boundary layer is continuously replaced by fresh material. Moreover, the product is in contact with the heating surface for only a few seconds and high temperature gradients can be used without the danger of causing undesirable reactions. SSHEs are versatile in the use of heat transfer medium and the various unit operations that can be carried out simultaneously. This article critically reviews the current understanding of the operations and applications of SSHEs.

  20. Paste heat exchange

    Energy Technology Data Exchange (ETDEWEB)


    The subject of coal paste heat exchangers is discussed in this letter report from Gelsenberg A.G. to I.G. Farbenindustrie A.G. Gelsenberg had given little consideration to the heating of coal paste by means of regeneration (heat exchange) because of the lack of experience in paste regeneration with bituminous coal, especially at 700 atmospheres. At the I.G. Farben plant at Poelitz, paste regeneration was carried out so that low concentration coal paste was heated in the regenerator together with the process gas, and the remaining coal was fed into the cold pass of the preheater in a thicker paste. Later tests proved this process viable. Gelsenberg heated normal coal paste and the gas in heat exchangers with the goal of relieving the preheater. Good results were achieved without change in design. The coal paste was heated with process gas in the regenerator at up to 315 degrees with constant pressure difference, so that after three months no decrease in K-values and no deposition or thickening was observed. Through the omission of paste gas, the pressure difference of the system became more constant and did not rise above the former level. The temperature also was more controllable, the chamber smoother running. Principal thermal data are given in a table. 1 table, 1 graph.

  1. The exchangeability of shape

    Directory of Open Access Journals (Sweden)

    Kaba Dramane


    Full Text Available Abstract Background Landmark based geometric morphometrics (GM allows the quantitative comparison of organismal shapes. When applied to systematics, it is able to score shape changes which often are undetectable by traditional morphological studies and even by classical morphometric approaches. It has thus become a fast and low cost candidate to identify cryptic species. Due to inherent mathematical properties, shape variables derived from one set of coordinates cannot be compared with shape variables derived from another set. Raw coordinates which produce these shape variables could be used for data exchange, however they contain measurement error. The latter may represent a significant obstacle when the objective is to distinguish very similar species. Results We show here that a single user derived dataset produces much less classification error than a multiple one. The question then becomes how to circumvent the lack of exchangeability of shape variables while preserving a single user dataset. A solution to this question could lead to the creation of a relatively fast and inexpensive systematic tool adapted for the recognition of cryptic species. Conclusions To preserve both exchangeability of shape and a single user derived dataset, our suggestion is to create a free access bank of reference images from which one can produce raw coordinates and use them for comparison with external specimens. Thus, we propose an alternative geometric descriptive system that separates 2-D data gathering and analyzes.

  2. Anion exchangers with branched functional ion exchange layers of different hydrophilicity for ion chromatography. (United States)

    Shchukina, O I; Zatirakha, A V; Smolenkov, A D; Nesterenko, P N; Shpigun, O A


    Novel polystyrene-divinylbenzene (PS-DVB) based anion exchangers differing from each other in the structure of the branched functional ion exchange layer are prepared to investigate the role of linker and functional site on ion exchange selectivity. The proposed method of synthesis includes the obtaining of aminated PS-DVB particles by means of their acylation with following reductive amination with methylamine. Further modification of the obtained secondary aminogroups is provided by the alkylation with either 1,4-butanediol diglycidyl ether (1,4-BDDGE) or resorcinol diglycidyl ether (RDGE), which form the linkers of different hydrophobicity, and amination of terminal epoxide rings with trimethylamine (TMA), dimethylethanolamine (DMEA), methyldiethanolamine (MDEA) or triethanolamine (TEA). The variation of the structure and hydrophobicity of the linker and terminal quaternary ammonium sites in the functional layer allows the alteration of selectivity and separation efficiency of the obtained adsorbents. The ion exchange selectivity and separation efficiency of the anion exchangers are evaluated using the model mixtures of anions (F(-), HCOO(-), Cl(-), NO2(-), Br(-), NO3(-), HPO4(2-) and SO4(2-)) in potassium hydroxide eluents. The adsorbents show the decrease of selectivity with increasing the hydrophilicity of the terminal functional site. The anion exchangers having more flexible and hydrophilic 1,4-BDDGE linker provide smaller separation factors for most of the analytes as compared with RDGE-containing adsorbents with the same terminal ion exchange sites, but are characterized with higher column efficiencies and better peak symmetry for polarizable anions. In case of 1,4-BDDGE-modified anion exchangers of the particle size of 3.3μm functionalized with DMEA and MDEA the calculated values of column efficiencies for polarizable NO3(-) and Br(-) are up to 49,000 and 53,000N/m, respectively, which is almost twice higher than the values obtained for the RDGE

  3. Inhibition of endogenous heat shock protein 70 attenuates inducible nitric oxide synthase induction via disruption of heat shock protein 70/Na(+) /H(+) exchanger 1-Ca(2+) -calcium-calmodulin-dependent protein kinase II/transforming growth factor β-activated kinase 1-nuclear factor-κB signals in BV-2 microglia. (United States)

    Huang, Chao; Lu, Xu; Wang, Jia; Tong, Lijuan; Jiang, Bo; Zhang, Wei


    Inducible nitric oxide synthase (iNOS) critically contributes to inflammation and host defense. The inhibition of heat shock protein 70 (Hsp70) prevents iNOS induction in lipopolysaccharide (LPS)-stimulated macrophages. However, the role and mechanism of endogenous Hsp70 in iNOS induction in microglia remains unclear. This study addresses this issue in BV-2 microglia, showing that Hsp70 inhibition or knockdown prevents LPS-induced iNOS protein expression and nitric oxide production. Real-time PCR experiments showed that LPS-induced iNOS mRNA transcription was blocked by Hsp70 inhibition. Further studies revealed that the inhibition of Hsp70 attenuated LPS-stimulated nuclear translocation and phosphorylation of nuclear factor (NF)-κB as well as the degradation of inhibitor of κB (IκB)-α and phosphorylation of IκB kinase β (IKKβ). This prevention effect of Hsp70 inhibition on IKKβ-NF-κB activation was found to be dependent on the Ca(2+) /calcium-calmodulin-dependent protein kinase II (CaMKII)/transforming growth factor β-activated kinase 1 (TAK1) signals based on the following observations: 1) chelation of intracellular Ca(2+) or inhibition of CaMKII reduced LPS-induced increases in TAK1 phosphorylation and 2) Hsp70 inhibition reduced LPS-induced increases in CaMKII/TAK1 phosphorylation, intracellular pH value, [Ca(2+) ]i , and CaMKII/TAK1 association. Mechanistic studies showed that Hsp70 inhibition disrupted the association between Hsp70 and Na(+) /H(+) exchanger 1 (NHE1), which is an important exchanger responsible for Ca(2+) influx in LPS-stimulated cells. These studies demonstrate that the inhibition of endogenous Hsp70 attenuates the induction of iNOS, which likely occurs through the disruption of NHE1/Hsp70-Ca(2+) -CaMKII/TAK1-NF-κB signals in BV-2 microglia, providing further insight into the functions of Hsp70 in the CNS. © 2015 Wiley Periodicals, Inc.

  4. The Dynamics of Multilateral Exchange (United States)

    Hausken, Kjell; Moxnes, John F.

    The article formulates a dynamic mathematical model where arbitrarily many players produce, consume, exchange, loan, and deposit arbitrarily many goods over time to maximize utility. Consuming goods constitutes a benefit, and producing, exporting, and loaning away goods constitute a cost. Utilities are benefits minus costs, which depend on the exchange ratios and bargaining functions. Three-way exchange occurs when one player acquires, through exchange, one good from another player with the sole purpose of using this good to exchange against the desired good from a third player. Such a triple handshake is not merely a set of double handshakes since the player assigns no interest to the first good in his benefit function. Cognitive and organization costs increase dramatically for higher order exchanges. An exchange theory accounting for media of exchange follows from simple generalization of two-way exchange. The examples of r-way exchange are the triangle trade between Africa, the USA, and England in the 17th and 18th centuries, the hypothetical hypercycle involving RNAs as players and enzymes as goods, and reaction-diffusion processes. The emergence of exchange, and the role of trading agents are discussed. We simulate an example where two-way exchange gives zero production and zero utility, while three-way exchange causes considerable production and positive utility. Maximum utility for each player is reached when exchanges of the same order as the number of players in society are allowed. The article merges micro theory and macro theory within the social, natural, and physical sciences.

  5. Cryogenic regenerative heat exchangers

    CERN Document Server

    Ackermann, Robert A


    An in-depth survey of regenerative heat exchangers, this book chronicles the development and recent commercialization of regenerative devices for cryogenic applications. Chapters cover historical background, concepts, practical applications, design data, and numerical solutions, providing the latest information for engineers to develop advanced cryogenic machines. The discussions include insights into the operation of a regenerator; descriptions of the cyclic and fluid temperature distributions in a regenerator; data for various matrix geometries and materials, including coarse and fine bronze, stainless steel-woven wire mesh screens, and lead spheres; and unique operating features of cryocoolers that produce deviations from ideal regenerator theory.

  6. Modeling Philippine Stock Exchange Composite Index Using Time Series Analysis (United States)

    Gayo, W. S.; Urrutia, J. D.; Temple, J. M. F.; Sandoval, J. R. D.; Sanglay, J. E. A.


    This study was conducted to develop a time series model of the Philippine Stock Exchange Composite Index and its volatility using the finite mixture of ARIMA model with conditional variance equations such as ARCH, GARCH, EG ARCH, TARCH and PARCH models. Also, the study aimed to find out the reason behind the behaviorof PSEi, that is, which of the economic variables - Consumer Price Index, crude oil price, foreign exchange rate, gold price, interest rate, money supply, price-earnings ratio, Producers’ Price Index and terms of trade - can be used in projecting future values of PSEi and this was examined using Granger Causality Test. The findings showed that the best time series model for Philippine Stock Exchange Composite index is ARIMA(1,1,5) - ARCH(1). Also, Consumer Price Index, crude oil price and foreign exchange rate are factors concluded to Granger cause Philippine Stock Exchange Composite Index.

  7. Developing bulk exchange spring magnets

    Energy Technology Data Exchange (ETDEWEB)

    Mccall, Scott K.; Kuntz, Joshua D.


    A method of making a bulk exchange spring magnet by providing a magnetically soft material, providing a hard magnetic material, and producing a composite of said magnetically soft material and said hard magnetic material to make the bulk exchange spring magnet. The step of producing a composite of magnetically soft material and hard magnetic material is accomplished by electrophoretic deposition of the magnetically soft material and the hard magnetic material to make the bulk exchange spring magnet.

  8. Characteristics of model heat exchanger (United States)

    Kolínský, Jan


    The aim of this paper is thermal analysis of model water to water heat exchanger at different mass flow rates. Experimental study deals with determination of total heat transfer - power of the heat exchanger. Furthermore the paper deals with analysis of heat exchanger charakcteristic using a definition of thermal efficiency. It is demonstrated that it is advisable to monitor the dependence of thermal efficiency and flow ratio.

  9. What Drives Stock Exchange Integration?

    National Research Council Canada - National Science Library

    Ekaterina Dorodnykh


    .... After a broad discussion of the existent literature, the investigation combines a large number of potentially relevant determinants for the explanation of whether stock exchanges are participating...

  10. Mastering Microsoft Exchange Server 2013

    CERN Document Server

    Elfassy, David


    The bestselling guide to Exchange Server, fully updated for the newest version Microsoft Exchange Server 2013 is touted as a solution for lowering the total cost of ownership, whether deployed on-premises or in the cloud. Like the earlier editions, this comprehensive guide covers every aspect of installing, configuring, and managing this multifaceted collaboration system. It offers Windows systems administrators and consultants a complete tutorial and reference, ideal for anyone installing Exchange Server for the first time or those migrating from an earlier Exchange Server version.Microsoft

  11. Hybrid Heat Exchangers (United States)

    Tu, Jianping Gene; Shih, Wei


    A hybrid light-weight heat exchanger concept has been developed that uses high-conductivity carbon-carbon (C-C) composites as the heat-transfer fins and uses conventional high-temperature metals, such as Inconel, nickel, and titanium as the parting sheets to meet leakage and structural requirements. In order to maximize thermal conductivity, the majority of carbon fiber is aligned in the fin direction resulting in 300 W/m.K or higher conductivity in the fin directions. As a result of this fiber orientation, the coefficient of thermal expansion (CTE) of the C-C composite in both non-fiber directions matches well with the CTE of various high-temperature metal alloys. This allows the joining of fins and parting sheets by using high-temperature braze alloys.

  12. The Radioecology Exchange

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, Catherine L.; Beresford, Nicholas A.; Patel, Sabera; Wells, Claire; Howard, Brenda J. [NERC Centre for Ecology and Hydrology, CEH Lancaster, Lancaster Environment Centre, Library Av., Bailrigg, Lancaster, LA1 4AP (United Kingdom); Mora, Juan Carlos; Real, Almudena [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Avenida complutense 22, Madrid, 28040 (Spain); Beaugelin-Seiller, Karine; Gilbin, Rodolphe; Hinton, Thomas [IRSN-Institut de Radioprotection et de Surete Nucleaire, 31, Avenue de la Division Leclerc, 92260 Fontenay-Aux-Roses (France); Vesterbacka, Pia; Muikku, Maarit; Outola, Iisa [Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881 Helsinki (Finland); Skuterud, Lavrans; AlbumYtre-Eide, Martin [Norwegian Radiation Protection Authority, Grini Naeringspark 13, Oesteraas, 1332 (Norway); Bradshaw, Clare; Stark, Karolina; Jaeschke, Ben [Stockholms Universitet, Universitetsvaegen 10, Stockholm, 10691 (Sweden); Oughton, Deborah; Skipperud, Lindis [NMBU Norwegian University of Life Science P.O. Box 5003N-1432 Aas, Oslo (Norway); Vandenhove, Hildegarde; Vanhoudt, Nathalie [SCK.CEN, Studiecentrum voor Kernenergie/Centre d' Etude de l' Energie Nucleaire, Avenue Herrmann-Debroux 40, BE-1160 Brussels (Belgium); Willrodt, Christine; Steiner, Martin [Bundesamt fuer Strahlenschutz, Willy-Brandt-Strasse 5, 38226 Salzgitter (Germany)


    The Radioecology Exchange ( was created in 2011 under the EU FP7 STAR (Strategy for Allied Radioecology) network of excellence. The project aims to integrate the research efforts on radioecology of nine European organisations into a sustainable network. The web site (together with associated Twitter feeds and Facebook page) currently provides the gateway to project outputs and other on-line radiation protection and radioecological resources. In 2013, the EU FP7 COMET (Coordination and implementation of a pan-European instrument for radioecology) project commenced; it aims to strengthen research on the impact of radiation on man and the environment. COMET includes the STAR partners with the addition of one Japanese and two Ukrainian research institutes. As STAR and COMET interact closely together and with the European Radioecology Alliance (, the Radioecology Exchange will be modified to become an international 'hub' for information related to radioecology. Project specific information will be hosted on separate web sites and This paper will present an overview of the resources hosted on the Radioecology Exchange inviting other scientists to contribute. Highlighted aspects of the site include: Social media (News blog, Twitter, Facebook) - Items announcing project outputs, training courses, jobs, studentships etc. Virtual laboratory - Information which encourages integration through joint research and integrated use of data and sample materials. These pages will focus on three categories: (1) Methodological: descriptions and video clips of commonly used analytical methods and protocols and the procedures used in STAR and COMET; (2) Informative: databases made available by STAR/COMET partners together with details of sample archives held. Fact-sheets on radio-ecologically important radionuclides and 'topical descriptions' which show absorbed

  13. Exchange rate risk in Central European countries

    Czech Academy of Sciences Publication Activity Database

    Kočenda, Evžen; Poghosyan, T.


    Roč. 60, č. 1 (2010), s. 22-39 ISSN 0015-1920 R&D Projects: GA ČR(CZ) GA402/08/1376; GA MŠk LC542 Institutional research plan: CEZ:MSM0021620846 Keywords : foreign exchange risk * time-varying risk premium * stochastic discount factor Subject RIV: AH - Economics Impact factor: 0.278, year: 2010

  14. Research on Heat Exchange Process in Aircraft Air Conditioning System (United States)

    Chichindaev, A. V.


    Using of heat-exchanger-condenser in the air conditioning system of the airplane Tu-204 (Boeing, Airbus, Superjet 100, MS-21, etc.) for cooling the compressed air by the cold air with negative temperature exiting the turbine results in a number of operational problems. Mainly it’s frosting of the heat exchange surface, which is the cause of live-section channels frosting, resistance increasing and airflow in the system decreasing. The purpose of this work is to analyse the known freeze-up-fighting methods for heat-exchanger-condenser, description of the features of anti-icing protection and offering solutions to this problem. For the problem of optimizing the design of heat exchangers in this work used generalized criterion that describes the ratio of thermal resistances of cold and hot sections, which include: the ratio of the initial values of heat transfer agents flow state; heat exchange surface finning coefficients; factors which describes the ratio of operating parameters and finning area. By controlling the ratio of the thermal resistances can be obtained the desired temperature of the heat exchange surface, which would prevent freezing. The work presents the results of a numerical study of the effect of different combinations of regime and geometrical factors changes on reduction of the heat-exchanger-condenser freezing surface area, including using of variable ratio of thermal resistances.

  15. Analysis of heat exchanger network for temperature fluctuation

    Directory of Open Access Journals (Sweden)

    Jin Zunlong


    Full Text Available Subject to temperature disturbance, exchangers in heat exchanger network will interact. It is necessary to evaluate the degree of temperature fluctuation in the network. There is inherently linear relationship between output and inlet temperatures of heat exchanger network. Based on this, the concept of temperature-change sensitivity coefficient was put forward. Quantitative influence of temperature fluctuation in the network was carried out in order to examine transmission character of temperature fluctuation in the system. And the information was obtained for improving the design quality of heat exchanger network. Favorable results were obtained by the introduced method compared with the experimental results. These results will assist engineers to distinguish primary and secondary influencing factors, which can be used in observing and controlling influencing factors accurately.

  16. Determinants of International Outsourcing and Performance: A Relational Exchange Perspective

    Directory of Open Access Journals (Sweden)

    Carl E. Dresden


    Full Text Available Prescriptive discussions regarding international outsourcing abound, but there are few previously proposed models of the antecedents leading to such sourcing. This empirical study utilizes the relational exchange framework proposed by Dwyer, Schurr and Oh (1987 and builds a conceptual model of the firm's use of international outsourcing within the context of relational exchange. The model concentrates on the aspects of relational exchange that are crucial antecedents to successful international outsourcing and empirically demonstrates how both economic and social factors have their influence. The resulting model demonstrates how cooperation, rather than competition, leads to successful international outsourcing.

  17. The city in motions : circulations, commercial exchanges and materiality of the city : a systemic approach of the factors of Parisian fabric evolution between the 15th century and the 19th century


    Hermenault, Léa


    In this work, we sought to understand effects of circulations on the Parisian urban fabric between the 15th and the first third of the 19th century, and, in particular, we sought to understand how it is evolving according to the interactions that develop at different scales between the materiality of the city and potentialities of exchange. The mapping of several corpus of planimetric and written data allow us to build our own geohistoric data, while theirs integration in a GIS bas made compa...

  18. Treasury Bond Market Segment at Bucharest Stock Exchange

    Directory of Open Access Journals (Sweden)

    Georgescu Maria Andrada


    Full Text Available The present paper aims to present the level of development reached by Romanian Treasury bond market segment at Bucharest Stock Exchange. A trial will be made to identify the determinants that contributed to the current level of development of domestic secondary government bond market and the factors that can generate a further (and improved development. The analysis will be descriptive (the data series available for Romanian are short, based on the secondary data offered by Bucharest Stock Exchange.

  19. 78 FR 69910 - Joint Industry Plan; BATS Exchange, Inc., BATS-Y Exchange, Inc., BOX Options Exchange LLC, C2... (United States)


    ... COMMISSION Joint Industry Plan; BATS Exchange, Inc., BATS-Y Exchange, Inc., BOX Options Exchange LLC, C2... LLC, NYSE Arca, Inc. and Topaz Exchange, LLC; Notice of Filing of Proposed National Market System Plan... and Exchange Commission (``Commission'') the proposed National Market System (``NMS'') Plan Governing...

  20. Liquid/liquid heat exchanger (United States)

    Miller, C. G.


    Conceptual design for heat exchanger, utilizing two immiscible liquids with dissimilar specific gravities in direct contact, is more efficient mechanism of heat transfer than conventional heat exchangers with walls or membranes. Concept could be adapted for collection of heat from solar or geothermal sources.

  1. Educators Exchange: A Program Evaluation. (United States)

    Armstrong, William B.

    The Educators Exchange Program (EEP) was established under a training and educational exchange agreement reached by California's San Diego Community College District (SDCCD) and the republic of Mexico. In the program, the District provided a 4-week technological training program to faculty at Centros de Capacitacion Tecnologica Industrial…

  2. Risk Balance in Exchange Protocols

    NARCIS (Netherlands)

    M.T. Dashti (Mohammad); Y. Wang (Yanjing); I. Cervesato


    htmlabstractWe study the behaviour of rational agents in exchange protocols which rely on trustees. We allow malicious parties to compromise the trustee by paying a cost and, thereby, present a game analysis that advocates exchange protocols which induce balanced risks on the participants. We also

  3. Professional Exchange: Mapping the Future. (United States)

    Dingman, Robert L.


    New associate editor of Professional Exchange section of "Journal of Mental Health Counseling" discusses importance of section. Lists potential topics suggested in 1989, then adds several other topics to the list. Concludes with guidelines for submission to Professional Exchange section. (NB)

  4. A cross-country Exchange Market Pressure (EMP dataset

    Directory of Open Access Journals (Sweden)

    Mohit Desai


    Full Text Available The data presented in this article are related to the research article titled - “An exchange market pressure measure for cross country analysis” (Patnaik et al. [1]. In this article, we present the dataset for Exchange Market Pressure values (EMP for 139 countries along with their conversion factors, ρ (rho. Exchange Market Pressure, expressed in percentage change in exchange rate, measures the change in exchange rate that would have taken place had the central bank not intervened. The conversion factor ρ can interpreted as the change in exchange rate associated with $1 billion of intervention. Estimates of conversion factor ρ allow us to calculate a monthly time series of EMP for 139 countries. Additionally, the dataset contains the 68% confidence interval (high and low values for the point estimates of ρ’s. Using the standard errors of estimates of ρ’s, we obtain one sigma intervals around mean estimates of EMP values. These values are also reported in the dataset.

  5. Heat exchanger leakage problem location

    Directory of Open Access Journals (Sweden)

    Jícha Miroslav


    Full Text Available Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.

  6. Transendothelial lipoprotein exchange and microalbuminuria

    DEFF Research Database (Denmark)

    Jensen, Jan Skov; Feldt-Rasmussen, Bo; Jensen, Kurt Svarre


    OBJECTIVE: Microalbuminuria associates with increased risk of atherosclerosis in individuals without diabetes. We hypothesized that transendothelial lipoprotein exchange is elevated among such individuals, possibly explaining increased intimal lipoprotein accumulation and thus atherosclerosis....... METHODS: Using an in vivo isotope technique, transendothelial exchange of low density lipoprotein (LDL) was measured in 77 non-diabetic individuals. Autologous 131-iodinated LDL was reinjected intravenously, and the 1-h fractional escape rate was calculated as index of transendothelial exchange. RESULTS......: There was no difference in transendothelial LDL exchange between subjects with microalbuminuria versus normoalbuminuria (mean (95% confidence interval) 3.8%/h (3.3-4.3%/h) versus 4.2%/h (3.7-4.7%/h); P=0.33). In contrast, there was a positive correlation between transendothelial LDL exchange and (logarithmically...

  7. Next Generation Microchannel Heat Exchangers

    CERN Document Server

    Ohadi, Michael; Dessiatoun, Serguei; Cetegen, Edvin


    In Next Generation Microchannel Heat Exchangers, the authors’ focus on the new generation highly efficient heat exchangers and presentation of novel data and technical expertise not available in the open literature.  Next generation micro channels offer record high heat transfer coefficients with pressure drops much less than conventional micro channel heat exchangers. These inherent features promise fast penetration into many mew markets, including high heat flux cooling of electronics, waste heat recovery and energy efficiency enhancement applications, alternative energy systems, as well as applications in mass exchangers and chemical reactor systems. The combination of up to the minute research findings and technical know-how make this book very timely as the search for high performance heat and mass exchangers that can cut costs in materials consumption intensifies.

  8. High Temperature Heat Exchanger Project

    Energy Technology Data Exchange (ETDEWEB)

    Anthony E. Hechanova, Ph.D.


    The UNLV Research Foundation assembled a research consortium for high temperature heat exchanger design and materials compatibility and performance comprised of university and private industry partners under the auspices of the US DOE-NE Nuclear Hydrogen Initiative in October 2003. The objectives of the consortium were to conduct investigations of candidate materials for high temperature heat exchanger componets in hydrogen production processes and design and perform prototypical testing of heat exchangers. The initial research of the consortium focused on the intermediate heat exchanger (located between the nuclear reactor and hydrogen production plan) and the components for the hydrogen iodine decomposition process and sulfuric acid decomposition process. These heat exchanger components were deemed the most challenging from a materials performance and compatibility perspective

  9. Fault-Tolerant Heat Exchanger (United States)

    Izenson, Michael G.; Crowley, Christopher J.


    A compact, lightweight heat exchanger has been designed to be fault-tolerant in the sense that a single-point leak would not cause mixing of heat-transfer fluids. This particular heat exchanger is intended to be part of the temperature-regulation system for habitable modules of the International Space Station and to function with water and ammonia as the heat-transfer fluids. The basic fault-tolerant design is adaptable to other heat-transfer fluids and heat exchangers for applications in which mixing of heat-transfer fluids would pose toxic, explosive, or other hazards: Examples could include fuel/air heat exchangers for thermal management on aircraft, process heat exchangers in the cryogenic industry, and heat exchangers used in chemical processing. The reason this heat exchanger can tolerate a single-point leak is that the heat-transfer fluids are everywhere separated by a vented volume and at least two seals. The combination of fault tolerance, compactness, and light weight is implemented in a unique heat-exchanger core configuration: Each fluid passage is entirely surrounded by a vented region bridged by solid structures through which heat is conducted between the fluids. Precise, proprietary fabrication techniques make it possible to manufacture the vented regions and heat-conducting structures with very small dimensions to obtain a very large coefficient of heat transfer between the two fluids. A large heat-transfer coefficient favors compact design by making it possible to use a relatively small core for a given heat-transfer rate. Calculations and experiments have shown that in most respects, the fault-tolerant heat exchanger can be expected to equal or exceed the performance of the non-fault-tolerant heat exchanger that it is intended to supplant (see table). The only significant disadvantages are a slight weight penalty and a small decrease in the mass-specific heat transfer.

  10. Electrically switched ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Lilga, M.A. [Pacific Northwest National Lab., Richland, WA (United States); Schwartz, D.T.; Genders, D.


    A variety of waste types containing radioactive {sup 137}Cs are found throughout the DOE complex. These waste types include water in reactor cooling basins, radioactive high-level waste (HLW) in underground storage tanks, and groundwater. Safety and regulatory requirements and economics require the removal of radiocesium before these wastes can be permanently disposed of. Electrically Switched Ion Exchange (ESIX) is an approach for radioactive cesium separation that combines IX and electrochemistry to provide a selective, reversible, and economic separation method that also produces little or no secondary waste. In the ESIX process, an electroactive IX film is deposited electrochemically onto a high-surface area electrode, and ion uptake and elution are controlled directly by modulating the potential of the film. For cesium, the electroactive films under investigation are ferrocyanides, which are well known to have high selectivities for cesium in concentrated sodium solutions. When a cathode potential is applied to the film, Fe{sup +3} is reduced to the Fe{sup +2} state, and a cation must be intercalated into the film to maintain charge neutrality (i.e., Cs{sup +} is loaded). Conversely, if an anodic potential is applied, a cation must be released from the film (i.e., Cs{sup +} is unloaded). Therefore, to load the film with cesium, the film is simply reduced; to unload cesium, the film is oxidized.


    Directory of Open Access Journals (Sweden)

    Polyakov Egor Nikolaevich


    Full Text Available We provide an analysis of real effective exchange rate dynamics in Russia throughout the last decade. Authors analysed the causes and consequences of real effective exchange growth and assessed how Russian ruble real effective exchange rate comply with its equilibrium level. Authors present results of empiric analysis of relationship between real effective exchange rate and labour productivity in industry of 20 european, asian countries and Russia. The result of this writing was the formulation of key copyright conclusions, namely: 1. The price level in the country (and the level of the real exchange rate of the national currency is a key factor of competitiveness. Accordingly, the real exchange rate of the national currency - is one of the most important policy tools. 2. The ruble today seriously overvalued. Overvaluation of the national currency relative to the equilibrium level is extremely harmful to the economy. Less recognized, but also widespread YaV it possible to the idea that an undervalued currency is a prerequisite for rapid economic growth. 3. A direct consequence of the growth of the real exchange rate in the past 12 years has been the growth of the external debt of the private sector. 4. Restraining the growth rate of the national currency - is also a common practice for countries who are concerned about the level of competitiveness. But Russia is this day-the only country of the G-20, which is impossible to control the REER.

  12. Custom, contract, and kidney exchange. (United States)

    Healy, Kieran; Krawiec, Kimberly D


    In this Essay, we examine a case in which the organizational and logistical demands of a novel form of organ exchange (the nonsimultaneous, extended, altruistic donor (NEAD) chain) do not map cleanly onto standard cultural schemas for either market or gift exchange, resulting in sociological ambiguity and legal uncertainty. In some ways, a NEAD chain resembles a form of generalized exchange, an ancient and widespread instance of the norm of reciprocity that can be thought of simply as the obligation to “pay it forward” rather than the obligation to reciprocate directly with the original giver. At the same time, a NEAD chain resembles a string of promises and commitments to deliver something in exchange for some valuable consideration--that is, a series of contracts. Neither of these salient "social imaginaries" of exchange--gift giving or formal contract--perfectly meets the practical demands of the NEAD system. As a result, neither contract nor generalized exchange drives the practice of NEAD chains. Rather, the majority of actual exchanges still resemble a simpler form of exchange: direct, simultaneous exchange between parties with no time delay or opportunity to back out. If NEAD chains are to reach their full promise for large-scale, nonsimultaneous organ transfer, legal uncertainties and sociological ambiguities must be finessed, both in the practices of the coordinating agencies and in the minds of NEAD-chain participants. This might happen either through the further elaboration of gift-like language and practices, or through a creative use of the cultural form and motivational vocabulary, but not necessarily the legal and institutional machinery, of contract.



    Podobeková, Veronika; Peráčková, Jana


    The article discusses utilization of heat from waste water in sewage. During the year, temperature of water in sewage ranges between 10 °C and 20 °C and the heat from sewage could be used for heating, cooling and hot water preparation in building. The heat is extracted through a transfer surface area of the heat exchanger into the heat pump, which is able to utilize the low–potential energy. Different design and types of the heat exchangers in sewage are dealt with: heat exchangers embedded i...

  14. Relational and XML Data Exchange

    CERN Document Server

    Arenas, Marcelo


    Data exchange is the problem of finding an instance of a target schema, given an instance of a source schema and a specification of the relationship between the source and the target. Such a target instance should correctly represent information from the source instance under the constraints imposed by the target schema, and it should allow one to evaluate queries on the target instance in a way that is semantically consistent with the source data. Data exchange is an old problem that re-emerged as an active research topic recently, due to the increased need for exchange of data in various for

  15. Heat exchanger using graphite foam (United States)

    Campagna, Michael Joseph; Callas, James John


    A heat exchanger is disclosed. The heat exchanger may have an inlet configured to receive a first fluid and an outlet configured to discharge the first fluid. The heat exchanger may further have at least one passageway configured to conduct the first fluid from the inlet to the outlet. The at least one passageway may be composed of a graphite foam and a layer of graphite material on the exterior of the graphite foam. The layer of graphite material may form at least a partial barrier between the first fluid and a second fluid external to the at least one passageway.

  16. Knowledge exchange and integrated services: experiences from an integrated community intellectual (learning) disability service for adults. (United States)

    Farrington, C; Clare, I C H; Holland, A J; Barrett, M; Oborn, E


    This paper examines knowledge exchange dynamics in a specialist integrated intellectual (learning) disability service, comprising specialist healthcare provision with social care commissioning and management, and considers their significance in terms of integrated service delivery. A qualitative study focusing on knowledge exchange and integrated services. Semi-structured interviews (n = 25) were conducted with members of an integrated intellectual disability service in England regarding their perceptions of knowledge exchange within the service and the way in which knowledge exchange impinges on the operation of the integrated service. Exchange of 'explicit' (codifiable) knowledge between health and care management components of the service is problematic because of a lack of integrated clinical governance and related factors such as IT and care record systems and office arrangements. Team meetings and workplace interactions allowed for informal exchange of explicit and 'tacit' (non-codifiable) knowledge, but presented challenges in terms of knowledge exchange completeness and sustainability. Knowledge exchange processes play an important role in the functioning of integrated services incorporating health and care management components. Managers need to ensure that knowledge exchange processes facilitate both explicit and tacit knowledge exchange and do not rely excessively on informal, 'ad hoc' interactions. Research on integrated services should take account of micro-scale knowledge exchange dynamics and relationships between social dynamics and physical factors. © 2014 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

  17. Effects of interest and exchange rate policies on Brazilian exports

    Directory of Open Access Journals (Sweden)

    Cláudia Maria Sonaglio


    Full Text Available In heterodox literature, the industrial sector is considered strategic for economic development. Consequently, reducing the contribution of this sector in the production of the country before it has reached the stage of economic maturity, affects the productive dynamics and slow technical progress. The appreciation of the real exchange rate is seen as one of the factors responsible for the reduction of the external competitiveness of Brazilian manufactures, and this exchange rate valuation may be occurring due to the differences between domestic and international interest rates. Given this context, the aim of this study is to evaluate the impact of changes in the monetary and exchange rate policy and in the composition of the total exports on the performance of the Brazilian economy using a structuralist model. The results reinforce the importance of the manufacturing sector to economic growth, especially in a competitive exchange rate environment.

  18. An evaluation of a European teacher exchange programme. (United States)

    Law, Kate; Muir, Nita; Thompson, Karen


    This longitudinal study evaluated a European teacher exchange programme within a UK School of Nursing and Midwifery. A cross case study design was employed over a three year period. A range of data methods were used which gave a clear, detailed and rich picture of the exchange experience. Overall analysis of the data generated two key themes, namely that of value and role identity. The study highlighted factors which were deemed to have positive and negative influences on the teacher exchange experience. It is concluded that a teacher exchange programme is of value to the School, by aiding personal and professional development and internationalisation. Recommendations from the study are included in the paper. 2010. Published by Elsevier Ltd.

  19. Hydraulic Validation of the LHC Cold Mass Heat Exchanger Tube

    CERN Document Server

    Provenaz, P


    The knowledge of the helium mass flow vs. the fraction of the tube wetted by the liquid helium II in the heat exchanger is a crucial input parameter for the heat exchange since the heat flux is direct ly proportional to the wetted surface. In the range of liquid and gas velocities inside the heat exchanger, the liquid flow behaves like in an open channel. Looking at the flow equations for such a s ituation, the velocity depends on the fluid properties only by the friction factor which is a function of the Reynolds number. Thus it was decided to build an experiment with water in order to check t he open channel equations in the heat exchanger geometry. This paper shows the results for water and gives the extrapolation for helium.

  20. How amide hydrogens exchange in native proteins. (United States)

    Persson, Filip; Halle, Bertil


    Amide hydrogen exchange (HX) is widely used in protein biophysics even though our ignorance about the HX mechanism makes data interpretation imprecise. Notably, the open exchange-competent conformational state has not been identified. Based on analysis of an ultralong molecular dynamics trajectory of the protein BPTI, we propose that the open (O) states for amides that exchange by subglobal fluctuations are locally distorted conformations with two water molecules directly coordinated to the N-H group. The HX protection factors computed from the relative O-state populations agree well with experiment. The O states of different amides show little or no temporal correlation, even if adjacent residues unfold cooperatively. The mean residence time of the O state is ∼100 ps for all examined amides, so the large variation in measured HX rate must be attributed to the opening frequency. A few amides gain solvent access via tunnels or pores penetrated by water chains including native internal water molecules, but most amides access solvent by more local structural distortions. In either case, we argue that an overcoordinated N-H group is necessary for efficient proton transfer by Grotthuss-type structural diffusion.

  1. Exchange Rates and Fundamentals. (United States)

    Engel, Charles; West, Kenneth D.


    We show analytically that in a rational expectations present-value model, an asset price manifests near-random walk behavior if fundamentals are I (1) and the factor for discounting future fundamentals is near one. We argue that this result helps explain the well-known puzzle that fundamental variables such as relative money supplies, outputs,…

  2. Pu Anion Exchange Process Intensification

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    This project seeks to improve the efficiency of the plutonium anion-exchange process for purifying Pu through the development of alternate ion-exchange media. The objective of the project in FY15 was to develop and test a porous foam monolith material that could serve as a replacement for the current anion-exchange resin, Reillex® HPQ, used at the Savannah River Site (SRS) for purifying Pu. The new material provides advantages in efficiency over the current resin by the elimination of diffusive mass transport through large granular resin beads. By replacing the large resin beads with a porous foam there is much more efficient contact between the Pu solution and the anion-exchange sites present on the material. Several samples of a polystyrene based foam grafted with poly(4-vinylpyridine) were prepared and the Pu sorption was tested in batch contact tests.

  3. Liquid droplet heat exchanger studies (United States)

    Bruckner, A. P.; Hedges, D. E.; Yungster, S.


    Recent analytical and experimental investigations of the liquid droplet heat exchanger (LDHX) concept for space power applications are described. The performance of the LDHX is compared to that of a conventional heat exchanger for heat rejection applications in a Brayton cycle, using the mass-specific heat exchanger effectiveness as a figure of merit. It is shown that the LDHX has an order of magnitude advantage over the conventional heat exchanger. Furthermore, significant improvement in cycle efficiency and power to mass ratio is possible. Two-phase flow experiments in a laboratory scale LDHX, using air and water as the two media, show very good agreement with the quasi-one-dimensional model used in the parametric studies.

  4. Estimating Foreign Exchange Reserve Adequacy

    Directory of Open Access Journals (Sweden)

    Abdul Hakim


    Full Text Available Accumulating foreign exchange reserves, despite their cost and their impacts on other macroeconomics variables, provides some benefits. This paper models such foreign exchange reserves. To measure the adequacy of foreign exchange reserves for import, it uses total reserves-to-import ratio (TRM. The chosen independent variables are gross domestic product growth, exchange rates, opportunity cost, and a dummy variable separating the pre and post 1997 Asian financial crisis. To estimate the risky TRM value, this paper uses conditional Value-at-Risk (VaR, with the help of Glosten-Jagannathan-Runkle (GJR model to estimate the conditional volatility. The results suggest that all independent variables significantly influence TRM. They also suggest that the short and long run volatilities are evident, with the additional evidence of asymmetric effects of negative and positive past shocks. The VaR, which are calculated assuming both normal and t distributions, provide similar results, namely violations in 2005 and 2008.

  5. VLER Health Exchange by Area (United States)

    Department of Veterans Affairs — “Connect Your Docs” through the Virtual Lifetime Electronic Record (VLER) Health Exchange program. This program gives VA and community health care providers secure...

  6. Counterflow Regolith Heat Exchanger Project (United States)

    National Aeronautics and Space Administration — The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat...

  7. Analysis of the Chinese Exchange Rate Stability

    Directory of Open Access Journals (Sweden)

    Youngrok Cheng


    Full Text Available Asian Financial Crisis now is moving to a relatively stable phase, and at this time, whether Chinese RMB will depreciate is raising the concern of the outside world. If we simply consider economic factors, we will find REER (Real Effective Exchange Rate increased around 10%, where depreciation factors are lurking. However, after Vice Premier Zhu Rongji took the responsibility of economic operation and fixed the fundamental key of developing stably, many foreign departments present good impetus of development. After that, Foreign Exchange Rate Reservation increases and major focus is put on long-term operation for debt structure. On the contrary, If Chinese RMB depreciates dramatically, there will be some uneasiness towards domestic economy and also the burden of paying debt should be increased, people may suffer the loss quite a lot. Especially even we consider the responsibility as the central country in this region and the political & economical factors causing the harmonious atmosphere of Sino-American relationship, it can be predicted that Chinese RMB cannot depreciate dramatically within 1-2 years.

  8. International Prices and Exchange Rates


    Gopinath, Gita; Burstein, Ariel


    We survey the recent empirical and theoretical developments in the literature on the relation between prices and exchange rates. After updating some of the major findings in the empirical literature we present a simple framework to interpret this evidence. We review theoretical models that generate insensitivity of prices to exchange rate changes through variable markups, both under flexible prices and nominal rigidities, first in partial equilibrium and then in general equilibrium.

  9. Exchange rate determination in Vietnam


    Thai-Ha Le


    This study investigates the determinants of the exchange rate in Vietnam and suggests policy implications. Gregory-Hansen cointegration tests and generalised variance decomposition (VDC) analysis were applied to monthly data from July 2004 to December 2013. The model was built based on the three popular approaches to exchange rate determination, which are purchasing power parity (PPP) approach, balance of payment (BOP) approach, and monetary and portfolio approach. This study finds that the p...

  10. Shared Year Exchange in Nursing

    DEFF Research Database (Denmark)

    Vedsegaard, Helle Wendner; Wederkinck, Elisabeth


    Beskrivelse af Shared Year Exchange in Nursing, et udviklingsporjekt omhandlende udvikling, beskrivelse og implementering af et fælles studieår for sygeplejerskestuderende ved Metropol og La Trobe University Australien.......Beskrivelse af Shared Year Exchange in Nursing, et udviklingsporjekt omhandlende udvikling, beskrivelse og implementering af et fælles studieår for sygeplejerskestuderende ved Metropol og La Trobe University Australien....

  11. Exchange Rate Exposure Management: "Speculation" in Non-Financial Companies

    DEFF Research Database (Denmark)

    Aabo, Tom

    "Speculation" in non-financial companies in relation to exchange rate exposure management constitutes one of the contributing factors behind corporate (or more widespread) crises. Deviations from benchmark positions constitute speculation. An empirical study of Danish non-financial companies finds...... that the larger the company (ability) and the larger its relative sale on foreign markets (relevance), the more likely the company will be to benchmark its exchange rate exposures. However, at the same time the very same factors (size and foreign sale) lead to more extensive speculation. Financial solvency (value...

  12. Patient Protection and Affordable Care Act; establishment of exchanges and qualified health plans; exchange standards for employers. Final rule, Interim final rule. (United States)


    This final rule will implement the new Affordable Insurance Exchanges ("Exchanges"), consistent with title I of the Patient Protection and Affordable Care Act of 2010 as amended by the Health Care and Education Reconciliation Act of 2010, referred to collectively as the Affordable Care Act. The Exchanges will provide competitive marketplaces for individuals and small employers to directly compare available private health insurance options on the basis of price, quality, and other factors. The Exchanges, which will become operational by January 1, 2014, will help enhance competition in the health insurance market, improve choice of affordable health insurance, and give small businesses the same purchasing clout as large businesses.

  13. An analysis of determinants of going concern audit opinion: Evidence from Tehran Stock Exchange

    Directory of Open Access Journals (Sweden)

    Hadi Mashadi Gharaghayah


    Full Text Available This paper presents an empirical investigation to find out important factors influencing exchange authorities for keeping firms on Tehran Stock Exchange. The proposed study uses logistic regression technique to study the effects of five factors including liquidity, solvability, profitability, cash flow and size of auditing firm. The results of the study show that only solvability is the most important factor according to auditing officials for extending listed firms on this exchange while the effects of other factors, liquidity, capability of meeting commitments, profitability, cash flow and size of auditing firm, are not statistically significance.

  14. Using register data to deduce patterns of social exchange. (United States)

    Jansson, Fredrik


    This paper presents a novel method for deducting propensities for social exchange between individuals based on the choices they make, and based on factors such as country of origin, sex, school grades and socioeconomic background. The objective here is to disentangle the effect of social ties from the other factors, in order to find patterns of social exchange. This is done through a control-treatment design on analysing available data, where the 'treatment' is similarity of choices between socially connected individuals, and the control is similarity of choices between non-connected individuals. Structural dependencies are controlled for and effects from different classes are pooled through a mix of methods from network and meta-analysis. The method is demonstrated and tested on Swedish register data on students at upper secondary school. The results show that having similar grades is a predictor of social exchange. Also, previous results from Norwegian data are replicated, showing that students cluster based on country of origin.

  15. Pengaruh Leader Member Exchange Terhadap Komitmen Organisasi Pada PT Midian Karya Pasuruan


    Prisetyadi, Amiruddin


    This study aimed to describe and explain the influence of leader member exchange toorganizational commitment of employees at PT Midian Karya Pasuruan. Data Analysis uses RangeScale and Simple Linear Regression. The results reveal that the Leader Member Exchange (LMX)show very strong and high in Organizational Commitment. Based on statistical tests and empiricalconditions in the company is known that the leader member exchange is one of the factors thatdetermine the commitment of the organizat...

  16. Fair Exchange in Strand Spaces

    Directory of Open Access Journals (Sweden)

    Joshua D. Guttman


    Full Text Available Many cryptographic protocols are intended to coordinate state changes among principals. Exchange protocols coordinate delivery of new values to the participants, e.g. additions to the set of values they possess. An exchange protocol is fair if it ensures that delivery of new values is balanced: If one participant obtains a new possession via the protocol, then all other participants will, too. Fair exchange requires progress assumptions, unlike some other protocol properties. The strand space model is a framework for design and verification of cryptographic protocols. A strand is a local behavior of a single principal in a single session of a protocol. A bundle is a partially ordered global execution built from protocol strands and adversary activities. The strand space model needs two additions for fair exchange protocols. First, we regard the state as a multiset of facts, and we allow strands to cause changes in this state via multiset rewriting. Second, progress assumptions stipulate that some channels are resilient-and guaranteed to deliver messages-and some principals are assumed not to stop at certain critical steps. This method leads to proofs of correctness that cleanly separate protocol properties, such as authentication and confidentiality, from invariants governing state evolution. G. Wang's recent fair exchange protocol illustrates the approach.

  17. Pu Anion Exchange Process Intensification

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, Kathryn M. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    This research is focused on improving the efficiency of the anion exchange process for purifying plutonium. While initially focused on plutonium, the technology could also be applied to other ion-exchange processes. Work in FY17 focused on the improvement and optimization of porous foam columns that were initially developed in FY16. These foam columns were surface functionalized with poly(4-vinylpyridine) (PVP) to provide the Pu specific anion-exchange sites. Two different polymerization methods were explored for maximizing the surface functionalization with the PVP. The open-celled polymeric foams have large open pores and large surface areas available for sorption. The fluid passes through the large open pores of this material, allowing convection to be the dominant mechanism by which mass transport takes place. These materials generally have very low densities, open-celled structures with high cell interconnectivity, small cell sizes, uniform cell size distributions, and high structural integrity. These porous foam columns provide advantages over the typical porous resin beads by eliminating the slow diffusion through resin beads, making the anion-exchange sites easily accessible on the foam surfaces. The best performing samples exceeded the Pu capacity of the commercially available resin, and also offered the advantage of sharper elution profiles, resulting in a more concentrated product, with less loss of material to the dilute heads and tails cuts. An alternate approach to improving the efficiency of this process was also explored through the development of a microchannel array system for performing the anion exchange.

  18. Electrically Switched Cesium Ion Exchange

    Energy Technology Data Exchange (ETDEWEB)

    JPH Sukamto; ML Lilga; RK Orth


    This report discusses the results of work to develop Electrically Switched Ion Exchange (ESIX) for separations of ions from waste streams relevant to DOE site clean-up. ESIX combines ion exchange and electrochemistry to provide a selective, reversible method for radionuclide separation that lowers costs and minimizes secondary waste generation typically associated with conventional ion exchange. In the ESIX process, an electroactive ion exchange film is deposited onto. a high surface area electrode, and ion uptake and elution are controlled directly by modulating the potential of the film. As a result, the production of secondary waste is minimized, since the large volumes of solution associated with elution, wash, and regeneration cycles typical of standard ion exchange are not needed for the ESIX process. The document is presented in two parts: Part I, the Summary Report, discusses the objectives of the project, describes the ESIX concept and the approach taken, and summarizes the major results; Part II, the Technology Description, provides a technical description of the experimental procedures and in-depth discussions on modeling, case studies, and cost comparisons between ESIX and currently used technologies.

  19. Geothermal heat exchanger with coaxial flow of fluids

    Directory of Open Access Journals (Sweden)

    Pejić Dragan M.


    Full Text Available The paper deals with a heat exchanger with coaxial flow. Two coaxial pipes of the secondary part were placed directly into a geothermal boring in such a way that geothermal water flows around the outer pipe. Starting from the energy balance of the exchanger formed in this way and the assumption of a study-state operating regime, a mathematical model was formulated. On the basis of the model, the secondary circle output temperature was determined as a function of the exchanger geometry, the coefficient of heat passing through the heat exchange areas, the average mass isobaric specific heats of fluid and mass flows. The input temperature of the exchanger secondary circle and the temperature of the geothermal water at the exit of the boring were taken as known values. Also, an analysis of changes in certain factors influencing the secondary water temperature was carried out. The parameters (flow temperature of the deep boring B-4 in Sijarinska Spa, Serbia were used. The theoretical results obtained indicate the great potential of this boring and the possible application of such an exchanger.

  20. Moving knowledge to action through dissemination and exchange. (United States)

    Gagnon, Michelle L


    The objective of this article is to discuss the knowledge dissemination and exchange components of the knowledge translation process that includes synthesis, dissemination, exchange, and ethically sound application of knowledge. This article presents and discusses approaches to knowledge dissemination and exchange and provides a summary of factors that appear to influence the effectiveness of these processes. It aims to provide practical information for researchers and knowledge users as they consider what to include in dissemination and exchange plans developed as part of grant applications. Not relevant. Dissemination is targeting research findings to specific audiences. Dissemination activities should be carefully and appropriately considered and outlined in a dissemination plan focused on the needs of the audience who will use the knowledge. Researchers should engage knowledge users to craft messages and help disseminate research findings. Knowledge brokers, networks, and communities of practice hold promise as innovative ways to disseminate and facilitate the application of knowledge. Knowledge exchange or integrated knowledge translation involves active collaboration and exchange between researchers and knowledge users throughout the research process. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Pervaporation with ion exchange membranes

    Energy Technology Data Exchange (ETDEWEB)

    Boeddeker, K.W.; Wenzlaff, A.


    Sorption and pervaporation of aqueous-organic solvent systems (water-ethanol; water-carboxylic acids) with commercial ion exchange membranes are compared to obtain information on polymersolvent interaction vs. coupling. Close agreement between sorption selectivity and pervaporation selectivity indicates coupling. If pervaporation is less selective than sorption, polymer-solvent interaction overtakes coupling, the limit of de-coupling being phase separation within the sorbate as signaled by a sudden increase in permeability of the lesser interacting component. As long as sorption and pervaporation operate in parallel, favoring enrichment of the same component, coupling enhances the separation effect. If pervaporation counteracts sorption, coupling is detrimental to the separation effect. Potential applications include the dehydration of pre-concentrated water-ethanol using anion exchange membranes, and the enrichment of acetic acid from dilute aqueous solution by pervaporative removal of water through cation exchange membranes.


    Directory of Open Access Journals (Sweden)

    Sandu Carmen


    Full Text Available The benefit of international trade is a more efficient employment of the productive forces of the world. (John Stuart Mill The exchange rate is a primary factor that influences economy. This instrument is used by some countries in order to improve the lack of balance caused as a result of the financial crisis felt in many countries considered by then infallible. The negative effects of the financial crisis can also be found in the decreased volume of commodities involved in international trade exchanges, as a consequence of modified prices and decreased offer. The globalizing trend leads to a constant expansion of exchanges between countries and to the consolidation of international cooperation. Except that economic interdependence generates an increased risk under the influence of economic, financial, monetary or political factors. The currency risk can generate either a gain or loss during foreign trade operations. The long period of RON depreciation made possible the entry of Romanian products on the international markets due to their prices. Sheltered by the gain generated by the evolution of the exchange rate, most of the exporters were not concerned by the increase of product competitiveness or by avoiding the currency risk. The fact that, for many years, the evolution of the exchange rate generated substantial losses for the exporters shows that risk coverage in Romania is, in most cases, a purely theoretical concept.

  3. Stability versus exchange: a paradox in DNA replication. (United States)

    Åberg, Christoffer; Duderstadt, Karl E; van Oijen, Antoine M


    Multi-component biological machines, comprising individual proteins with specialized functions, perform a variety of essential processes in cells. Once assembled, most such complexes are considered very stable, retaining individual constituents as long as required. However, rapid and frequent exchange of individual factors in a range of critical cellular assemblies, including DNA replication machineries, DNA transcription regulators and flagellar motors, has recently been observed. The high stability of a multi-protein complex may appear mutually exclusive with rapid subunit exchange. Here, we describe a multisite competitive exchange mechanism, based on simultaneous binding of a protein to multiple low-affinity sites. It explains how a component can be stably integrated into a complex in the absence of competing factors, while able to rapidly exchange in the presence of competing proteins. We provide a mathematical model for the mechanism and give analytical expressions for the stability of a pre-formed complex, in the absence and presence of competitors. Using typical binding kinetic parameters, we show that the mechanism is operational under physically realistic conditions. Thus, high stability and rapid exchange within a complex can be reconciled and this framework can be used to rationalize previous observations, qualitatively as well as quantitatively. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  4. The Determinants of Real Exchange Rate Volatility in Nigeria

    African Journals Online (AJOL)


    interest rates, domestic and foreign money supply, the exchange rate regime and central bank independence (Stancik, 2007). The degree of the impact of each of these factors varies and depends on a particular country's economic condition. Thus, the countries that are in the transition process (such as. Nigeria) are more ...


    Directory of Open Access Journals (Sweden)

    Eduard Dadyan


    Full Text Available In this paper we present the results of neural network analysis of the effect of significant factors on the quotation of the exchange rate on the example of the formation of the dollar in terms of «the turbulence of the economy» in Russia.

  6. Oscillating-Coolant Heat Exchanger (United States)

    Scotti, Stephen J.; Blosser, Max L.; Camarda, Charles J.


    Devices useful in situations in which heat pipes inadequate. Conceptual oscillating-coolant heat exchanger (OCHEX) transports heat from its hotter portions to cooler portions. Heat transported by oscillation of single-phase fluid, called primary coolant, in coolant passages. No time-averaged flow in tubes, so either heat removed from end reservoirs on every cycle or heat removed indirectly by cooling sides of channels with another coolant. Devices include leading-edge cooling devices in hypersonic aircraft and "frost-free" heat exchangers. Also used in any situation in which heat pipe used and in other situations in which heat pipes not usable.


    Directory of Open Access Journals (Sweden)



    Full Text Available The experience of recentyears showsthat it hasa fundamentalroleformation mechanismof the exchange rateinmacroeconomic stabilization. Global economiccrises, oil shockshave shownthe difficultyoffloatingsustainabilitybyparticipants in the system. EuropeanMonetary System, focused onconcertedfloatingcurrenciestoECU, was formedunder the conditionsin which somecountries have adoptedregional monetaryarrangements(EU countries, with suchbasescurrencyregimeshybridthat combinesspecific mechanismsto those offixedratefree floating. This paperaims to demonstratethe important role thatithasthe choice ofexchange rateregimeas abasic elementin thefoundationofmacroeconomic stabilizationinstruments. Consideredan expression of thestateof the domestic economyandinternationalcompetitiveness, the exchange rate is determined bya complex set ofexternal factorsorinternalstabilityisa prerequisite forthe crisis.

  8. Proton exchange membrane fuel cells

    CERN Document Server

    Qi, Zhigang


    Preface Proton Exchange Membrane Fuel CellsFuel CellsTypes of Fuel CellsAdvantages of Fuel CellsProton Exchange Membrane Fuel CellsMembraneCatalystCatalyst LayerGas Diffusion MediumMicroporous LayerMembrane Electrode AssemblyPlateSingle CellStackSystemCell Voltage Monitoring Module (CVM)Fuel Supply Module (FSM)Air Supply Module (ASM)Exhaust Management Module (EMM)Heat Management Module (HMM)Water Management Module (WMM)Internal Power Supply Module (IPM)Power Conditioning Module (PCM)Communications Module (COM)Controls Module (CM)SummaryThermodynamics and KineticsTheoretical EfficiencyVoltagePo

  9. [Histone variants and histone exchange]. (United States)

    Wu, Nan; Gui, Jian-Fang


    Histones, as the basic components of nucleosome, are essential to chromatin structure and function. To adapt to various states of chromatin, corresponding histone variants are incorporated in nucleosome, and certain modifications also occur on the variants' tails. These variants change the conformation and stability of nucleosome to facilitate transcriptional activation or deactivation, DNA repairing, heterochromatin formation, and others. During histone exchange, chromatin remodeling complex facilitates histone variant deposition into nucleosome, and different variants have diverse deposition pathways. Recently, research on histone variants is not only a new hotspot in epigenetics, but also a new annotation of "histone code". In addition, histone exchange reveals new changing mechanism of DNA-histone interaction.

  10. Isotopically exchangeable Al in coastal lowland acid sulfate soils

    Energy Technology Data Exchange (ETDEWEB)

    Yvanes-Giuliani, Yliane A.M. [UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052 (Australia); Centre Européen de Recherche et d' Enseignement des Géosciences de l' Environnement, Aix-Marseille Université, Aix en Provence (France); Fink, D. [Centre Européen de Recherche et d' Enseignement des Géosciences de l' Environnement, Aix-Marseille Université, Aix en Provence (France); Rose, J. [Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Waite, T. David [UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052 (Australia); Collins, Richard N., E-mail: [UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052 (Australia)


    Periodic discharges of high concentrations of aluminium (Al) causing fish kills and other adverse effects occur worldwide in waterways affected by coastal lowland acid sulfate soils (CLASS). The exchangeability — a metal's ability to readily transfer between the soil solid- and solution-phases — of Al in these soils is therefore of particular importance as it has implications for metal transport, plant availability and toxicity to living organisms. In the present study, the concentrations of isotopically exchangeable Al (E values) were measured in 27 CLASS and compared with common salt extractions (i.e. KCl and CuCl{sub 2}) used to estimate exchangeable soil pools of Al. E values of Al were high in the soils, ranging from 357 to 3040 mg·kg{sup −1}. Exchangeable concentrations estimated using 1 M KCl were consistently lower than measured E values, although a reasonable correlation was obtained between the two values (E = 1.68 × Al{sub KCl}, r{sup 2} = 0.66, n = 25). The addition of a 0.2 M CuCl{sub 2} extraction step improved the 1:1 agreement between extractable and isotopically exchangeable Al concentrations, but lead to significant mobilisation of non-isotopically exchangeable Al in surficial ‘organic-rich’ CLASS having E values < 1000 mg·kg{sup −1}. It was concluded that currently used (i.e. 1 M KCl) methodology severely underestimates exchangeable Al and total actual acidity values in CLASS and should be corrected by a factor similar to the one determined here. - Highlights: • Isotopically exchangeable Al was compared to 1 M KCl or 0.2 M CuCl{sub 2} extractable Al. • 1 M KCl always underestimated isotopically exchangeable Al concentrations. • 0.2 M CuCl{sub 2} mobilised non-isotopically exchangeable Al • 1 M KCl values require correction of ~ 1.7 to reflect exchangeable Al concentrations.

  11. Carbon dioxide exchange between an undisturbed old-growth temperate forest and the atmosphere (United States)

    D.Y. Hollinger; F.M. Kelliher; J.N. Byers; J.E. Hunt; T.M. McSeveny; P.L. Weir


    We used the eddy-correlation technique to investigate the exchange of C02 between an undisturbed old-growth forest and the atmosphere at a remote Southern Hemisphere site on 15 d between 1989 and 1990. Our goal was to determine how environmental factors regulate ecosystem CO2 exchange, and to test whether present knowledge...

  12. An investigation on the role of thermal fins in the design of micro heat exchangers

    DEFF Research Database (Denmark)

    Omidvarnia, Farzaneh; Hansen, Hans Nørgaard; Sarhadi, Ali


    heat exchanger in comparison with the effective factors in designing its macro counterpart ar e investigated. Numerical si mulations in the finite element software COMSOL are used to evaluate the thermal performance of both micro and macro heat exchangers. The result of the analysis reveals the fact...

  13. Social Exchange and Sexual Behavior in Young Women's Premarital Relationships in Kenya (United States)

    Luke, Nancy; Goldberg, Rachel E.; Mberu, Blessing U.; Zulu, Eliya M.


    Transactional sex, or the exchange of money and gifts for sexual activities within nonmarital relationships, has been widely considered a contributing factor to the disproportionate prevalence of HIV/AIDS among young women in sub-Saharan Africa. This study applied social exchange theory to premarital relationships in order to investigate the…

  14. Land-use change arising from rural land exchange : an agent-based simulation model

    NARCIS (Netherlands)

    Bakker, Martha M.; Alam, Shah Jamal; van Dijk, Jerry; Rounsevell, Mark D. A.

    Land exchange can be a major factor driving land-use change in regions with high pressure on land, but is generally not incorporated in land-use change models. Here we present an agent-based model to simulate land-use change arising from land exchange between multiple agent types representing

  15. Land-use change arising from rural land exchange: an agent-based simulation model

    NARCIS (Netherlands)

    Bakker, M.M.; Alam, S.J.; Dijk, van J.; Rounsevell, M.D.A.


    Land exchange can be a major factor driving land-use change in regions with high pressure on land, but is generally not incorporated in land-use change models. Here we present an agent-based model to simulate land-use change arising from land exchange between multiple agent types representing

  16. Solvent accessibility of protein surfaces by amide H/2H exchange MALDI-TOF mass spectrometry. (United States)

    Truhlar, Stephanie M E; Croy, Carrie H; Torpey, Justin W; Koeppe, Julia R; Komives, Elizabeth A


    One advantage of detecting amide H/2H exchange by mass spectrometry instead of NMR is that the more rapidly exchanging surface amides are still detectable. In this study, we present quench-flow amide H/2H exchange experiments to probe how rapidly the surfaces of two different proteins exchange. We compared the amide H/2H exchange behavior of thrombin, a globular protein, and IkappaBalpha, a nonglobular protein, to explore any differences in the determinants of amide H/2H exchange rates for each class of protein. The rates of exchange of only a few of the surface amides were as rapid as the "intrinsic" exchange rates measured for amides in unstructured peptides. Most of the surface amides exchanged at a slower rate, despite the fact that they were not seen to be hydrogen bonded to another protein group in the crystal structure. To elucidate the influence of the surface environment on amide H/2H exchange, we compared exchange data with the number of amides participating in hydrogen bonds with other protein groups and with the solvent accessible surface area. The best correlation with amide H/2H exchange was found with the total solvent accessible surface area, including side chains. In the case of the globular protein, the correlation was modest, whereas it was well correlated for the nonglobular protein. The nonglobular protein also showed a correlation between amide exchange and hydrogen bonding. These data suggest that other factors, such as complex dynamic behavior and surface burial, may alter the expected exchange rates in globular proteins more than in nonglobular proteins where all of the residues are near the surface.

  17. Macroeconomic sources of foreign exchange risk in new EU members

    Czech Academy of Sciences Publication Activity Database

    Kočenda, Evžen; Poghosyan, T.


    Roč. 33, č. 11 (2009), s. 2164-2173 ISSN 0378-4266 R&D Projects: GA ČR(CZ) GA402/08/1376; GA MŠk LC542 Institutional research plan: CEZ:MSM0021620846 Keywords : foreign exchange risk * time-varying risk premium * Stochastic discount factor * new EU member countries Subject RIV: AH - Economics Impact factor: 1.908, year: 2009

  18. Exchange asymmetry in experimental settings (United States)

    Thomas C. Brown; Mark D. Morrison; Jacob A. Benfield; Gretchen Nurse Rainbolt; Paul A. Bell


    We review past trading experiments and present 11 new experiments designed to show how the trading rate responds to alterations of the experimental procedure. In agreement with earlier studies, results show that if the trade decision is converted to one resembling a choice between goods the exchange asymmetry disappears, but otherwise the asymmetry is...


    Directory of Open Access Journals (Sweden)



    Full Text Available Using spectral analysis is very common in technical areas but rather unusual in economics and finance, where ARIMA and GARCH modeling are much more in use. To show that spectral analysis can be useful in determining hidden periodic components for high-frequency finance data as well, we use the example of foreign exchange rates

  20. Our International Art Exchange Project. (United States)

    Cocciolone, Kathy R.


    Discusses an international art exchange project designed to teach fifth-grade students that the culture of a country is reflected in its art and that art is a universal language. Describes the contributions from Scotland, Mexico, Saudi Arabia, Egypt, Japan, and India. Points out ways to use materials in schools. (KO)

  1. Milk fouling in heat exchangers

    NARCIS (Netherlands)

    Jeurnink, T.J.M.


    The mechanisms of fouling of heat exchangers by milk were studied. Two major fouling mechanisms were indentified during the heat treatment of milk: (i) the formation and the subsequent deposition of activated serum protein molecules as a result of the heat denaturation; (ii) the

  2. Update of telephone exchange switches

    CERN Multimedia


    Within the scope of the CERN phone services improvement, a software update will be done on exchange switches on Wednesday 27 october from 7.00 pm to 12.00 pm. Disturbances or even interruptions of telephony services may occur during this intervention. We appology in advance for any inconveniences that may occur.

  3. Maintenance of CERN telephone exchanges

    CERN Multimedia


    A maintenance of CERN telephone exchanges will be performed on 21st, 22nd, 23rd, 24th of September from 7 p.m. to 9 p.m. Disturbances or even interruptions of telephony services may occur during this lapse of time. We apology in advance for any inconveniences that this may cause.

  4. The Commodity and its Exchange

    DEFF Research Database (Denmark)

    Høst, Jeppe Engset


    and the value of the quota are examined through the concrete exchange of fishing rights, and it is explained why quota trade can give rise to speculation and monopolies. In the final part of the chapter, it is argued that the value of transferable fishing quotas rely on a social relation between owners...... and nonowners of quota, as a form of monopoly rent....

  5. Baltic Exchange teper v Tallinne

    Index Scriptorium Estoniae


    Viimane osa merekonteineritesse kokkupakitud Londoni laevandus- ja merebörsi Baltic Exchange'i endise peakorteri detailidest jõudis 2007. a. juunis Tallinna. Hoone detailid ostnud ärimehed Heiti Hääl ja Eerik-Niiles Kross plaanivad leida hoonele koha Tallinna kesklinnas. E.-N. Krossi kommentaar

  6. Energy Exchange NASA Opening Plenary (United States)

    Marrs, Rick


    Rick Marrs, Deputy Assistant Administrator Office of Strategic Infrastructure NASA Headquarters will be speaking during the 2017 Energy Exchange opening plenary. His presentation showcases the NASA mission, sustainability at NASA, NASA's strategic Sustainability Performance Plan, Existing PV Partnerships, and NASA funded Solar Initiatives at KSC.

  7. Homans on Exchange: Hedonism Revived (United States)

    Abrahamsson, Bengt


    George C. Homan's theory on social exchange is critically examined and found to have serious shortcomings with regard to its deductive and inductive aspects. An expecially prominent shortcoming concerns the tautological character of his concept of reward," which makes his theory deductively unclear and empirically untestable. Homan's critique…

  8. Common knowledge in email exchanges

    NARCIS (Netherlands)

    Sietsma, F.; Apt, K.R.; van Eijck, D.J.N.; Verbrugge, R.


    We consider a framework in which a group of agents communicates by means of emails, with the possibility of replies, forwards and blind carbon copies (BCC). We study the epistemic consequences of such email exchanges by introducing an appropriate epistemic language and semantics. This allows us to

  9. Knowledge Exchange with Sistema Scotland (United States)

    Allan, Julie; Moran, Nikki; Duffy, Celia; Loening, Gica


    This paper reports on a knowledge exchange project, funded by the Scottish Funding Council and undertaken by a group of researchers from three higher education institutions in Scotland and the project partner, Sistema Scotland. This newly established charity is attempting to implement a major programme of social change, developed in Venezuela,…

  10. Inflationary trispectrum from graviton exchange

    DEFF Research Database (Denmark)

    Seery, David; Sloth, Martin Snoager; Vernizzi, Filippo


    We compute the connected four-point correlation function of the primordial curvature perturbation generated during inflation with standard kinetic terms, where the correlation is established via exchange of a graviton between two pairs of scalar fluctuations. Any such correlation yields a contrib...

  11. Exchange Rate Expectations and the Current Exchange Rate: A Test of the Monetarist Approach


    V S Somanath


    The monetarist model of the exchange rate includes expectations of the future exchange rate as a determinant of the current exchange rate. This paper investigates whether expectations are a significant determinant of the exchange rate. An expectations process that is consistent with a basic monetarist exchange rate model is considered. Alternative measures of expectations are generated using this process. In the empirical tests, while the standard forward exchange premium measure of expectati...

  12. Phase exposure-dependent exchange (United States)

    Ginn, T. R.; Schreyer, L. G.; Zamani, K.


    Solutes and suspended material often experience delays during exchange between phases one of which may be moving. Consequently transport often exhibits combined effects of advection/dispersion, and delays associated with exchange between phases. Such processes are ubiquitous and include transport in porous/fractured media, watersheds, rivers, forest canopies, urban infrastructure systems, and networks. Upscaling approaches often treat the transport and delay mechanisms together, yielding macroscopic "anomalous transport" models. When interaction with the immobile phase is responsible for the delays, it is not the transport that is anomalous, but the lack of it, due to delays. We model such exchanges with a simple generalization of first-order kinetics completely independent of transport. Specifically, we introduce a remobilization rate coefficient that depends on the time in immobile phase. Memory-function formulations of exchange (with or without transport) can be cast in this framework, and can represent practically all time-nonlocal mass balance models including multirate mass transfer and its equivalent counterparts in the continuous time random walk and time-fractional advection dispersion formalisms, as well as equilibrium exchange. Our model can address delayed single-/multievent remobilizations as in delay-differential equations and periodic remobilizations that may be useful in sediment transport modeling. It is also possible to link delay mechanisms with transport if so desired, or to superpose an additional source of nonlocality through the transport operator. This approach allows for mechanistic characterization of the mass transfer process with measurable parameters, and the full set of processes representable by these generalized kinetics is a new open question.

  13. Compact Ceramic Microchannel Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Lewinsohn, Charles [Ceramatec, Inc., Salt Lake City, UT (United States)


    The objective of the proposed work was to demonstrate the feasibility of a step change in power plant efficiency at a commercially viable cost, by obtaining performance data for prototype, compact, ceramic microchannel heat exchangers. By performing the tasks described in the initial proposal, all of the milestones were met. The work performed will advance the technology from Technology Readiness Level 3 (TRL 3) to Technology Readiness Level 4 (TRL 4) and validate the potential of using these heat exchangers for enabling high efficiency solid oxide fuel cell (SOFC) or high-temperature turbine-based power plants. The attached report will describe how this objective was met. In collaboration with The Colorado School of Mines (CSM), specifications were developed for a high temperature heat exchanger for three commercial microturbines. Microturbines were selected because they are a more mature commercial technology than SOFC, they are a low-volume and high-value target for market entry of high-temperature heat exchangers, and they are essentially scaled-down versions of turbines used in utility-scale power plants. Using these specifications, microchannel dimensions were selected to meet the performance requirements. Ceramic plates were fabricated with microchannels of these dimensions. The plates were tested at room temperature and elevated temperature. Plates were joined together to make modular, heat exchanger stacks that were tested at a variety of temperatures and flow rates. Although gas flow rates equivalent to those in microturbines could not be achieved in the laboratory environment, the results showed expected efficiencies, robust operation under significant temperature gradients at high temperature, and the ability to cycle the stacks. Details of the methods and results are presented in this final report.


    Directory of Open Access Journals (Sweden)

    Handan AKSUYEK,


    Full Text Available As with all sectors, recent extreme changes occurred in the exchange rates have substantially affected the construction operations. While the rise in foreign exchange rates leads to harmful effects in the negative direction at the operations having foreign exchange – based debt or it provides also advantageous effect in the positive direction at the construction companies having foreign exchange – indexed investments. In this context, this sudden change in foreign exchange rates which cannot be predicted beforehand and emerges as a result of speculative events. As with all operations carrying out foreign exchange – based tasks, these fluctuations in the foreign exchange rate head first among the factors which affect the achievement or failure of the cost or profit targets previously determined by the construction companies as well. Therefore, the companies whose costs and profits consist of different units of currency in their construction agreements should apply to the hedging methods in order to be protected against the exchange rate. As for the main tools of protection method are the derivative products such as forward, futures, swap and optional contracts. In this study, the effect of exchange rate fluctuations on the completion costs of construction projects is scrutinized. Moreover, the tools which may be employed by the construction companies in order to get rid of exchange rate which adversely influence the building companies in both directions have been comparatively evaluated.

  15. Political Economy of Exchange Rate Regimes: A Panel Data Analysis of Selected European Countries

    Directory of Open Access Journals (Sweden)

    Ahmet BEŞKAYA


    Full Text Available The aim of this study is to investigate the effects of economic and political factors on the choice of exchange rate regimes. In order to achieve this goal, we apply for Binary Choice Panel Probit Model to examine the relationships between exchange rate regimes and financial depth, real exchange rate, capital inflow and democracy. Our data covers the period of 1980-2013 for the selected EU countries, namely, Austria, Germany, Belgium, France, Denmark, England, Sweden and Italy. Estimation results demonstrates that the choice of fixed exchange rate regime become disadvantageous and flexible exchange rate turn out to be the right choice as financial depth, real exchange rate, capital inflow and democratization increases.

  16. Using a health information exchange system for imaging information: patterns and predictors. (United States)

    Vest, Joshua R; Grinspan, Zachary M; Kern, Lisa M; Campion, Thomas R; Kaushal, Rainu


    Health information exchange (HIE) systems may address the challenges that prevent easy access to patients' existing radiological information at the point of care. However, little is known about the factors associated with usage of HIE for radiology reports, nor about how reports are shared with an exchange network. We analyzed the system log files from a regional health information organization in upstate New York matched with insurance claims files using network analysis and regression modeling. The exchange network was dominated by a few key information sources. Outpatient users overall accessed 17 times more radiology reports than inpatient and ED users combined. Additionally, as the number of exchange partners increased per organization, the average number of reports exchanged by that organization also increased. Radiology reports were most likely to be accessed by physicians and other clinical users. These findings have implications for those operating and fostering exchange activity.

  17. Characterising the exchangeability of phenanthrene associated with naturally occurring soil colloids using an isotopic dilution technique. (United States)

    Tavakkoli, Ehsan; Juhasz, Albert; Donner, Erica; Lombi, Enzo


    The association of polycyclic aromatic hydrocarbons (PAHs) with inorganic and organic colloids is an important factor influencing their bioavailability, mobility and degradation in the environment. Despite this, our understanding of the exchangeability and potential bioavailability of PAHs associated with colloids is limited. The objective of this study was to use phenanthrene as a model PAH compound and develop a technique using (14)C phenanthrene to quantify the isotopically exchangeable and non-exchangeable forms of phenanthrene in filtered soil water or sodium tetraborate extracts. The study was also designed to investigate the exchangeability of colloidal phenanthrene as a function of particle size. Our findings suggest that the exchangeability of phenanthrene in sodium tetraborate is controlled by both inorganic and organic colloids, while in aqueous solutions inorganic colloids play the dominant role (even though coating of these by organic matter cannot be excluded). Filter pore size did not have a significant effect on phenanthrene exchangeability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. The Examination o f Fina ncial Performance o f Companies i n Tourism S ector, Which Are Being, Traded i n Exchange Istanbul (E I With Data Envelopment Analysis a nd Total Factor Productivity

    Directory of Open Access Journals (Sweden)

    Emre Yakut


    Full Text Available Performance analysis is an indication of the extent to which companies use resources they have effectively and efficiently in line with the objectives of company. Ratio analysis for activity analysis, one of the techniques that are used to measure performances of companies, parametric and non-parametric methods are applied. The aim of this study is to research the financial efficiencies of 9 tourism companies which are processed in EI 100 between 2009 -2013 with the help of financial statements.Data Envelopment Analysis (DEA which is one of none parametric mathematical programming based efficiency measuring method is used to measure for organizational efficiency and Malmquist Total Factor Productivity (TFP used in this study. According to the criteria set by the active and inactive as a result of the analysis, tourism businesses have been identified

  19. Rethinking ASGISA and the rand exchange rate

    Directory of Open Access Journals (Sweden)

    Willem H Boshoff


    Full Text Available Abstract: The ASGISA policy document identifies the exchange rate as one of the factors constraining accelerated growth in South Africa. This note argues that currency developments do not translate into business cycle movements in the aggregate economy, and that a weaker exchange rate is less likely to boost either foreign investment or export performance in the face of regulatory uncertainty. The South African government has recently launched the Accelerated and Shared Growth Initiative (ASGISA aimed at raising the long-term growth path of the economy. The plan identifies several so-called “binding constraints” that are considered to be inhibiting the economy from rising to more elevated levels of economic growth. One such “constraint”, according to the ASGISA policy document, is the “volatility and level of the currency” (Republic of South Africa, 2006. By including this issue, policymakers have signalled that fluctuations in the Rand are considered significant to broader economic fluctuations in South Africa. This research note questions such a conviction by offering evidence that currency fluctuations are not mirrored in the South African business cycle. Nonetheless, proponents may argue that a weaker Rand will stimulate particular sectors, mostly those that are export-oriented, while it will boost Foreign Direct Investment (FDI. However, this note argues further that a weaker Rand is less likely to generate sustainable improvement in either export-oriented industries or FDI in the absence of other reforms. The following sections consider these two issues in sequence.

  20. Ion-exchange concentration of inorganic anions from aqueous solution

    Directory of Open Access Journals (Sweden)

    L. P. Bondareva


    Full Text Available Monitoring of natural waters in the present time - consuming process, the accuracy of which is influenced by many factors: the composition of water, the presence of impurities and "interfering" components. The water sample preparation process includes the step of concentration and separation of ions determined. The most versatile, efficient, and frequently used method is the concentration of inorganic anions from aqueous solutions by ion exchanger, which can optimize the composition of water to the optimal for identification and quantitative determination of anions. The characteristics of sorption chloride, nitrate and sulfate ions of basic anion exchange resin AВ-17 and Purolite A430 were compared in the article. The constants of protolysis of ion exchangers both AB 17 and Purolite A430 are the same and equal 0.037 ± 0,002. The value of total capacity (POE Purolite A430 was 4.3 mmol/g, AB 17 – 3.4 mmol/g. The studied ion exchangers have the same type of ionic groups – quaternary ammonium, but their number and denotes differ. The number of quaternary ammonium groups is higher in Purolite A430, respectively the number of absorbed anions of these ion exchanger is higher. The values of dynamic exchange capacity (DOE of ion exchanger Purolite A430 is higher than these values of AB-17 and equal to 1.48 ± 0.03 mmol / dm3 for chloride ion, 1.50 ± 0.03 mmol / dm3 for nitrate ion, 1.62 ± 0.03 mmol / dm3 for sulfate ion. The values of the POE and DOE of anion-exchange resins Purolite A430 and AV-17 and the characteristics of the individual sorption of chloride, nitrate, sulfate ions showed an advantage of the Purolite for the concentrationing of anions. It is found that times of anions sorption from triple-anion solutions by Purolite A430 are significantly different for different anions, and these times are close for anion-exchanger AV-17. It proves the possibility of quantitative separation and concentration by anion-exchanger Purolite A430.


    Directory of Open Access Journals (Sweden)

    Егор Николаевич Поляков


    Full Text Available We provide an analysis of real effective exchange rate dynamics in Russia throughout the last decade. Authors analysed the causes and consequences of real effective exchange growth and assessed how Russian ruble real effective exchange rate comply with its equilibrium level. Authors present results of empiric analysis of relationship between real effective exchange rate and labour productivity in industry of 20 european, asian countries and Russia.The result of this writing was the formulation of key copyright conclusions, namely:1. The price level in the country (and the level of the real exchange rate of the national currency is a key factor of competitiveness. Accordingly, the real exchange rate of the national currency - is one of the most important policy tools.2. The ruble today seriously overvalued. Overvaluation of the national currency relative to the equilibrium level is extremely harmful to the economy. Less recognized, but also widespread YaV it possible to the idea that an undervalued currency is a prerequisite for rapid economic growth.3. A direct consequence of the growth of the real exchange rate in the past 12 years has been the growth of the external debt of the private sector.4. Restraining the growth rate of the national currency - is also a common practice for countries who are concerned about the level of competitiveness. But Russia is this day-the only country of the G-20, which is impossible to control the REER.DOI:

  2. Exchange Rate Instability and Sectoral Exports: Evidence from Pakistan

    Directory of Open Access Journals (Sweden)

    Muhammad Haseeb


    Full Text Available Exports of a country is one of the main factors indicating economic health of a country and fluctuating exchange rates and relative price can significantly affect the level of exports and it is an alarming situation for a country when its exports are affected by exchange rate volatility. Impact of exchange rate volatility and relative price on trade has been a heated debate in the field of finance and most of work has been done on aggregate and bilateral trade. Few researches are found on product basis especially in the scenario of Pakistan. This research will provide an overview of the exports of 13 different products from Pakistan. Secondary data is used to analyze the impact of exchange rate instability on the exports of different products from Pakistan to all over the world. Significance of the study depends on the right choice of estimation method. We use auto regressive distributive lags (ARDL method to check the relationship of two main variables. Glass, meat and paper & board products show that relative price affects negatively to exports so Government should make policies to strengthen the exports of these three products. Government can provide subsidies on these products in order to boost up the exports and make these products competitive in international market. Under the shadow of our results we conclude that exchange rate volatility has significant negative relationship with the exports of food processing machinery, grapes, meat and petroleum products so government needs to be focused on it when exchange rate are highly instable. Iron & steel bars show short run negative impact of exchange rate however this impact is adjusted in the long run.

  3. The Motivations of Exchange Students at Scandinavian Universities

    DEFF Research Database (Denmark)

    Caudery, Tim; Petersen, Margrethe; Shaw, Philip


    In Europe, exchange students increasingly travel to countries where they will use English, rather than the national language, as the medium of their instruction. Previous research has largely focussed on students of languages learning the language of their host countries. Here we report...... generally for improving English but only three in ten expressing any interest in learning a new language. It is striking, however, that around four in ten subjects did not mention improving English as part of their motivation, even when prompted, suggesting that they think their English skills are already...... on a section of a project[1] on non-language students, intended to identify the motivational factors associated with exchange visits. A total of 194 exchange students spread across four host institutions, two in Sweden, two in Denmark, were interviewed. Language learning motivation varied, with high motivation...

  4. Modular Heat Exchanger With Integral Heat Pipe (United States)

    Schreiber, Jeffrey G.


    Modular heat exchanger with integral heat pipe transports heat from source to Stirling engine. Alternative to heat exchangers depending on integrities of thousands of brazed joints, contains only 40 brazed tubes.

  5. Flexible Exchange of Farming Device Data

    DEFF Research Database (Denmark)

    Iftikhar, Nadeem; Pedersen, Torben Bach


    A new trend in the farming business is to replace conventional farming devices with computerized farming devices. Accordingly, numerous computer-based farming devices for logging, processing and exchanging data have recently been installed on moving farm machinery such as tractors. The exchange...... of data generally takes place between the devices and farming systems, mostly installed at the premises of farmers, contractors, advisory services etc. In most cases, data exchange is based on farming data exchange standards and is bi-directional. Bi-directional data exchange allows different devices...... and systems to exchange data based on a predefined set of rules. In consequence, many hand-coded data exchange solutions have been developed in the farming business. Although efforts regarding incorporating data exchange standards have been made, their actual usage so far has been limited, due to the fact...

  6. Exploring stakeholder perceptions of facilitators and barriers to using needle exchange programs in Yunnan Province, China

    National Research Council Canada - National Science Library

    Philbin, Morgan M; FuJie, Zhang


    .... Though the Ministry of Health has scaled-up needle exchange programs (NEPs), they have not received official government recognition nor have they been extensively evaluated to explore factors influencing their acceptability and feasibility...

  7. Rethinking exchange market models as optimization algorithms (United States)

    Luquini, Evandro; Omar, Nizam


    The exchange market model has mainly been used to study the inequality problem. Although the human society inequality problem is very important, the exchange market models dynamics until stationary state and its capability of ranking individuals is interesting in itself. This study considers the hypothesis that the exchange market model could be understood as an optimization procedure. We present herein the implications for algorithmic optimization and also the possibility of a new family of exchange market models

  8. Latin American foreign exchange intervention - Updated


    Da Silva, Sergio; Nunes, Mauricio


    We examine Latin American foreign exchange intervention in a framework where the exchange rate regime is endogenous and there exists an inefficient, equilibrium foreign exchange intervention bias. The model suggests that greater central bank independence is associated with lesser intervention in the foreign exchange market, and also with leaning-against-the-wind intervention. Both results are confirmed by data from 13 Latin American countries.

  9. How to stabilize the currency exchange rate


    BLINOV, Sergey


    In 2015, many countries had to deal with the weakening of their currencies. Issues regarding exchange rate management by the Central Banks have again become the focal point of heated debate. For example, the Russian Ruble exchange rate has been fluctuating hugely. The problem now is not so much the Ruble's weakness as instability of its exchange rate, volatility. The management of the Central Bank claims that stabilization of the Ruble exchange rate is not possible though it is the respons...

  10. Heat exchanger and related methods (United States)

    Turner, Terry D.; McKellar, Michael G.


    Heat exchangers include a housing having an inlet and an outlet and forming a portion of a transition chamber. A heating member may form another portion of the transition chamber. The heating member includes a first end having a first opening and a second end having a second opening larger than the first opening. Methods of conveying a fluid include supplying a first fluid into a transition chamber of a heat exchanger, supplying a second fluid into the transition chamber, and altering a state of a portion of the first fluid with the second fluid. Methods of sublimating solid particles include conveying a first fluid comprising a material in a solid state into a transition chamber, heating the material to a gaseous state by directing a second fluid through a heating member and mixing the first fluid and the second fluid.

  11. The picture exchange communication system. (United States)

    Bondy, A S; Frost, L A


    The Picture Exchange Communication System (PECS) was developed as a means to teach children with autism and related developmental disabilities a rapidly acquired, self-initiating, functional communication system. Its theoretical roots combine principles from applied behavior analysis and guidelines established within the field of alternative and augmentative communication. This approach has several potential advantages relative to imitation-based strategies (both vocal and gestural) and symbol selection strategies. The system begins with the exchange of simple icons but rapidly builds "sentence" structure. The system also emphasizes developing the request function prior to developing responding to simple questions and commenting. The development of requesting with a sentence structure also permits the rapid development of attributes more traditionally taught within a receptive mode. The relationship between the introduction of PECS and various other behavioral issues (i.e., social approach and behavior management) as well as its relationship to the codevelopment of speech are reviewed.

  12. Analysis of Leader Member Exchange

    Directory of Open Access Journals (Sweden)

    Adi Santoso


    Full Text Available This research aims to find out how the relationship of superiors and subordinates works or we call it, LEADER MEMBER EXCHANGE (LMX in another term. The object of this research is an Integrated Nursing Home for Impaired Speech and Hearing (INISPH, ''Meohai” Kendari, with 5 superiors and subordinates of this institution as the research informants. The method used in this research is descriptive qualitative analysis. The research found that the relationship of superiors and subordinates or Leader Member Exchange (LMX, has been well-intertwined, based on the affection, loyalty, enormous contribution, and respect one another toward the profession done in creating a close relationship to achieve the goal.DOI: 10.15408/etk.v15i2.3244

  13. Value Appropriation in Business Exchange

    DEFF Research Database (Denmark)

    Ellegaard, Chris; Medlin, Christopher J.; Geersbro, Jens


    master the difficult balance between value creation and appropriation. This review has provided an overview of the many managerial options for value appropriation and created knowledge on the effects of the various appropriation mechanisms enabling managers to secure company rents while not jeopardizing......Purpose – Value appropriation is a central, yet neglected aspect in business exchange research. The purpose of the paper is to generate an overview of research on active value appropriation in business exchange and provide the foundation for further research into value appropriation, as well...... as some initial guidance for managers. Design/methodology/approach – Literatures investigating value appropriation were identified by the means of a systematic review of the overall management literature. Findings – The authors provide an overview and comparison of the literatures and find that they apply...

  14. High Temperature Composite Heat Exchangers (United States)

    Eckel, Andrew J.; Jaskowiak, Martha H.


    High temperature composite heat exchangers are an enabling technology for a number of aeropropulsion applications. They offer the potential for mass reductions of greater than fifty percent over traditional metallics designs and enable vehicle and engine designs. Since they offer the ability to operate at significantly higher operating temperatures, they facilitate operation at reduced coolant flows and make possible temporary uncooled operation in temperature regimes, such as experienced during vehicle reentry, where traditional heat exchangers require coolant flow. This reduction in coolant requirements can translate into enhanced range or system payload. A brief review of the approaches and challengers to exploiting this important technology are presented, along with a status of recent government-funded projects.

  15. Groundwater–Surface Water Exchange

    DEFF Research Database (Denmark)

    Karan, Sachin

    The exchange of groundwater-surface water has been invetigated in the western part of Denmark. Holtum AA provides the framework for all the performed investigations. Several methods are used, primarily eld based measurements ombined with numerical models to achieve insight to the governing...... processes of interaction between groundwater and surface water. By using heat as a tracer it has been possible to use temperature directly as calibrationtargets in a groundwater and heat transport model. Thus, it is possible to use heat investigate the change in groundwater discharge in dynamic conditions...... by using simple temperature devices along a stream to delineate the areas of interest in regard to GW{SW exchange. Thus, at several locations in a stream a temperature data logger was placed in the water column and right at the streambed-water interface. By looking at the correlation of streambed...

  16. Electrically controlled cesium ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Lilga, M. [Pacific Northwest Lab., Richland, WA (United States)


    Several sites within the DOE complex (Savannah River, Idaho, Oak Ridge and Hanford) have underground storage tanks containing high-level waste resulting from nuclear engineering activities. To facilitate final disposal of the tank waste, it is advantageous to separate and concentrate the radionuclides for final immobilization in a vitrified glass matrix. This task proposes a new approach for radionuclide separation by combining ion exchange (IX) and electrochemistry to provide a selective and economic separation method.

  17. Value-Added Exchange Rates


    Rudolfs Bems; Robert C. Johnson


    This paper updates the conceptual foundations for measuring real effective exchange rates (REERs) to allow for vertical specialization in trade. We derive a value-added REER describing how demand for the value added that a country produces changes as the price of its value added changes relative to competitors. We then compute this index for 42 countries from 1970-2009 using trade measured in value added terms and GDP deflators. There are substantial differences between value-added and conven...

  18. Exchange, phenomenology and the Self


    Galonska, Deniece; Yener, Efe Can; Sørensen, Karen Mallya; Olesen, Tine Lautrup


    The research project aims to investigate the ‘Self’ concerning the experience of being an international exchange student. As the research approaches the three participants as unique individuals, phenomenology provided a foundation regarding the ontological stance and a method. The philosophy of phenomenology and its different interview methods will be discussed, in relation to perspectives by Edmund Husserl and Martin Heidegger, with attention aimed at the question whether or not objectiv...

  19. Review of Fractal Heat Exchangers


    Huang, Zhiwei; Hwang, Yunho; Aute, Vikrant; Radermacher, Reinhard


    Nature has inspired many scientists and engineers to solve problems through observation and mimicry. One such example is heat transfer enhancement. The enormous natural heat and mass transfer phenomena have led engineers to seek solutions to heat transfer enhancement problems from nature. Fractal geometries are found in respiratory and vascular systems of plants and animals, such as blood vessels, human lungs, leaves, coastlines, etc. Inspired by this, fractal heat exchangers have been develo...

  20. Prison needle exchange programs work. (United States)


    On 27 October 2004 the Canadian HIV/AIDS Legal Network and the Ontario Medical Association (OMA) released reports recommending that needle exchange programs (NEPs) be implemented in prisons, based on evidence that such programs promote and protect the health of both prisoners and prison staff. At the same time, the Scottish Prison Service announced that it was looking at providing such programs, and an Iranian physician reported on a pilot project in his country.

  1. Ion-exchange chromatographic protein refolding

    NARCIS (Netherlands)

    Freydell, E.; Wielen, van der L.; Eppink, M.H.M.; Ottens, M.


    The application of ion-exchange (IEX) chromatography to protein refolding (IExR) has been successfully proven, as supported by various studies using different model proteins, ion-exchange media and flow configurations. Ion-exchange refolding offers a relatively high degree of process

  2. Monetary and Exchange Rate Policy in Slovenia


    Gonzalo Caprirolo; Vladimir Lavrac


    The paper is divided in three sections presenting some stylized facts concerning monetary and exchange rate policy framework in Slovenia. Three periods are covered: Money-based Stabilization Policy (1991-1995), Price and Real Exchange Rate Stability Dual Targeting Policy (1996-2001), and Exchange Rate Based Stabilization Policy and Accession to ERM2 (2001-).

  3. 78 FR 38203 - Refunds and Exchanges (United States)


    ... Service through the manager, Payment Technology, USPS Headquarters. Subsequently, as part of this final... from the manager, Payment Technology (see 608.8.1 for address). * * * * * 9.0 Exchanges and Refunds... Not Exchangeable The following postage items cannot be exchanged: a. Adhesive stamps, unless mistakes...

  4. Cryogenic Heat Exchanger with Turbulent Flows (United States)

    Amrit, Jay; Douay, Christelle; Dubois, Francis; Defresne, Gerard


    An evaporator-type cryogenic heat exchanger is designed and built for introducing fluid-solid heat exchange phenomena to undergraduates in a practical and efficient way. The heat exchanger functions at liquid nitrogen temperature and enables cooling of N[subscript 2] and He gases from room temperatures. We present first the experimental results of…

  5. The magic of knowledge exchange

    CERN Multimedia

    CERN Bulletin


    “If you have an apple and I have an apple and we exchange these apples then you and I will still each have one apple. But if you have an idea and I have an idea and we exchange these ideas, then each of us will have two ideas”. (George Bernard Shaw). The CERN Global Network is a new, ideal place for past and present members of the CERN community to share ideas and create new links.   On 29 April, CERN’s Knowledge and Technology Transfer (KTT) Group launched the CERN Global Network, a tool whose aim is to facilitate knowledge exchanges inside and outside CERN. "Among the greatest ambassadors of knowledge are people who have been trained and educated at CERN and also at other institutes: here is where the Global Network comes into play", says Rolf Heuer, CERN Director General. “During the first phase, the Network will be open to current and former members of the CERN personnel, that is, staff, fellows, apprentices, associates, students a...


    Energy Technology Data Exchange (ETDEWEB)

    Bunge, A.L.; Klein, G.; Radke, C.J.


    Exchange of hardness ions is important in enhanced oil recovery with chemical additives. In both micellar-polymer and caustic flooding processes, multivalent ions released from rock surfaces can interact with anionic surfactants, rendering them preferentially oil soluble and/or insoluble in water. Because hardness cations are sparingly soluble and precipitate in alkaline solutions, such solutions may be more efficient as surfactant flood preflushes than are softened brines. Multivalent ion precipitation may also occur in alkaline waterflooding. To permit design of such processes, this paper presents a chromatographic theory for simultaneous ion exchange with precipitation of divalent ions. Theoretical effluent histories and concentration profiles are presented for the cases of finite pulses and continuous injection of hydroxide ions into linear cores. Complete capture of the insoluble salt particles is assumed. Results are given for the case of instantaneous equilibration of the solution with the precipitate, as well for the case of complete nonequilibrium, in which the solid precipitate does not redissolve. The efficiency of alklaine preflushing is shown to depend on the exchange isotherm, initial divalent loading of the rock, injected pH and salinity, the solubility product of the precipitated salt, and pulse size. The effect of slug size on complete equilibrium removal of hardness ions is reduced efficiency with increasing size until a critical volume approximating continuous injection is reached. Increasing injected pH and salinity provides a more favorable response. Experimental data for Berea sandstone and an argillaceous sand compare favorably with the proposed theory.


    Energy Technology Data Exchange (ETDEWEB)

    Boltz, J.C. (ed.)


    This report discusses the following topics on computer environments: Releasing computer software outside EG G Idaho; Ilford digital photo imager; mandatory upgrade of PC ORPS software; ORPS host computer upgrade; EROB computer users see network change; password expiration notice; big iron still has place in HPC market; handy scripts to copy and move files; more on workstation password expiration; training center course schedule for April 1993; Microsoft Word Version 5.1a- button bar; file attributes can provide you greater flexibility; constructing a personal WordPerfect dictionary; and Windows shortcuts.

  8. Long-Run Determinants of the Real Exchange Rate; A Stock-Flow Perspective


    Hamid Faruqee


    This paper examines the long-run determinants of the real exchange rate from a stock-flow perspective. The empirical analysis estimates a long-run relationship between the real exchange rate, net foreign assets, and other factors affecting trade flows. Using postwar data for the United States and Japan, cointegration analysis supports the finding that the structural factors underlying each country's net trade and net foreign asset positions determine the long-run path for the real value of th...

  9. Ultrafast dynamics of hydrogen bond exchange in aqueous ionic solutions. (United States)

    Park, Sungnam; Odelius, Michael; Gaffney, Kelly J


    The structural and dynamical properties of aqueous ionic solutions influence a wide range of natural and biological processes. In these solutions, water has the opportunity to form hydrogen bonds with other water molecules and anions. Knowing the time scale with which these configurations interconvert represents a key factor to understanding the influence of molecular scale heterogeneity on chemical events in aqueous ionic solutions. We have used ultrafast IR spectroscopy and Car-Parrinello molecular dynamics (CPMD) simulations to investigate the hydrogen bond (H-bond) structural dynamics in aqueous 6 M sodium perchlorate (NaClO4) solution. We have measured the H-bond exchange dynamics between spectrally distinct water-water and water-anion H-bond configurations with 2DIR spectroscopy and the orientational relaxation dynamics of water molecules in different H-bond configurations with polarization-selective IR pump-probe experiments. The experimental H-bond exchange time correlates strongly with the experimental orientational relaxation time of water molecules. This agrees with prior observations in water and aqueous halide solutions, and has been interpreted within the context of an orientational jump model for the H-bond exchange. The CPMD simulations performed on aqueous 6 M NaClO4 solution clearly demonstrate that water molecules organize into two radially and angularly distinct structural subshells within the first solvation shell of the perchlorate anion, with one subshell possessing the majority of the water molecules that donate H-bonds to perchlorate anions and the other subshell possessing predominantly water molecules that donate two H-bonds to other water molecules. Due to the high ionic concentration used in the simulations, essentially all water molecules reside in the first ionic solvation shells. The CPMD simulations also demonstrate that the molecular exchange between these two structurally distinct subshells proceeds more slowly than the H

  10. Simulated-tempering replica-exchange method for the multidimensional version. (United States)

    Mitsutake, Ayori


    In this article, the general formulation of the multidimensional simulated-tempering replica-exchange method is described. In previous works, the one-dimensional replica-exchange simulated-tempering and simulated-tempering replica-exchange methods were developed. For the former method, the weight factor of the one-dimensional simulated tempering is determined by a short replica-exchange simulation and multiple-histogram reweighing techniques. For the latter method, the production run is a replica-exchange simulation with a few replicas not in the canonical ensembles but in the simulated-tempering ensembles which cover wide ranges of temperature. Recently, the general formulation of the multidimensional replica-exchange simulated tempering was presented. In this article, the extension of the simulated-tempering replica-exchange method for the multidimensional version is given. As an example of applications of the algorithm, a two-dimensional replica-exchange simulation and two simulated-tempering replica-exchange simulations have been performed. Here, an alpha-helical peptide system with a model solvent has been used for the applications.

  11. A Review of Industrial Heat Exchange Optimization (United States)

    Yao, Junjie


    Heat exchanger is an energy exchange equipment, it transfers the heat from a working medium to another working medium, which has been wildly used in petrochemical industry, HVAC refrigeration, aerospace and so many other fields. The optimal design and efficient operation of the heat exchanger and heat transfer network are of great significance to the process industry to realize energy conservation, production cost reduction and energy consumption reduction. In this paper, the optimization of heat exchanger, optimal algorithm and heat exchanger optimization with different objective functions are discussed. Then, optimization of the heat exchanger and the heat exchanger network considering different conditions are compared and analysed. Finally, all the problems discussed are summarized and foresights are proposed.

  12. Distinct PKA and Epac compartmentalization in airway function and plasticity

    NARCIS (Netherlands)

    Dekkers, Bart G. J.; Racke, Kurt; Schmidt, Martina

    Asthma and chronic obstructive pulmonary disease (COPD) are obstructive lung diseases characterized by airway obstruction, airway inflammation and airway remodelling. Next to inflammatory cells and airway epithelial cells, airway mesenchymal cells, including airway smooth muscle cells and

  13. Heat exchanger with oscillating flow (United States)

    Scotti, Stephen J. (Inventor); Blosser, Max L. (Inventor); Camarda, Charles J. (Inventor)


    Various heat exchange apparatuses are described in which an oscillating flow of primary coolant is used to dissipate an incident heat flux. The oscillating flow may be imparted by a reciprocating piston, a double action twin reciprocating piston, fluidic oscillators or electromagnetic pumps. The oscillating fluid flows through at least one conduit in either an open loop or a closed loop. A secondary flow of coolant may be used to flow over the outer walls of at least one conduit to remove heat transferred from the primary coolant to the walls of the conduit.

  14. Information exchanges in cournot duopolies

    Directory of Open Access Journals (Sweden)

    Faíña Medín J. Andrés


    Full Text Available In this paper we analyze the profitability of information sharing among Cournot oligopolists receiving private information about random demand. We model the random demand as a linear demand having, 1 an unknown intercept, and 2 an unknown slope. In each of these two scenarios, firms observe private signals about the unknown parameter. We show that in the scenario-1, if the private signal observed by firms is accurate enough, information exchange is profitable and in the scenario-2, if there is a sufficiently large variation in the demand slope and private signals are accurate enough, firms earn strictly higher profits by sharing their information rather than keeping it private.



    V. L. Dobin; V. G. Demikhov; M. P. Zharikova


    The review analyzes the major foreign publications on the iron exchange in mycobacteria for the recent years. The issues of iron absorption by tuberculous mycobacteria, its preservation and regulation of their metabolism have been reviewed. Deeper and more detail description of the above process will provide new opportunities for therapeutic interventions into it and assist in development of new tuberculosis treatment techniques.


    Directory of Open Access Journals (Sweden)

    V. L. Dobin


    Full Text Available The review analyzes the major foreign publications on the iron exchange in mycobacteria for the recent years. The issues of iron absorption by tuberculous mycobacteria, its preservation and regulation of their metabolism have been reviewed. Deeper and more detail description of the above process will provide new opportunities for therapeutic interventions into it and assist in development of new tuberculosis treatment techniques.

  17. EPR of exchange coupled systems

    CERN Document Server

    Bencini, Alessandro


    From chemistry to solid state physics to biology, the applications of Electron Paramagnetic Resonance (EPR) are relevant to many areas. This unified treatment is based on the spin Hamiltonian approach and makes extensive use of irreducible tensor techniques to analyze systems in which two or more spins are magnetically coupled. This edition contains a new Introduction by coauthor Dante Gatteschi, a pioneer and scholar of molecular magnetism.The first two chapters review the foundations of exchange interactions, followed by examinations of the spectra of pairs and clusters, relaxation in oligon

  18. Suppression of the Nuclear Factor Eny2 Increases Insulin Secretion in Poorly Functioning INS-1E Insulinoma Cells

    Directory of Open Access Journals (Sweden)

    P. Dames


    Full Text Available Eny2, the mammalian ortholog of yeast Sus1 and drosophila E(y2, is a nuclear factor that participates in several steps of gene transcription and in mRNA export. We had previously found that Eny2 expression changes in mouse pancreatic islets during the metabolic adaptation to pregnancy. We therefore hypothesized that the protein contributes to the regulation of islet endocrine cell function and tested this hypothesis in rat INS-1E insulinoma cells. Overexpression of Eny2 had no effect but siRNA-mediated knockdown of Eny2 resulted in markedly increased glucose and exendin-4-induced insulin secretion from otherwise poorly glucose-responsive INS-1E cells. Insulin content, cellular viability, and the expression levels of several key components of glucose sensing remained unchanged; however glucose-dependent cellular metabolism was higher after Eny2 knockdown. Suppression of Eny2 enhanced the intracellular incretin signal downstream of cAMP. The use of specific cAMP analogues and pathway inhibitors primarily implicated the PKA and to a lesser extent the EPAC pathway. In summary, we identified a potential link between the nuclear protein Eny2 and insulin secretion. Suppression of Eny2 resulted in increased glucose and incretin-induced insulin release from a poorly glucose-responsive INS-1E subline. Whether these findings extend to other experimental conditions or to in vivo physiology needs to be determined in further studies.

  19. 31 CFR 515.325 - National securities exchange. (United States)


    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false National securities exchange. 515.325... Definitions § 515.325 National securities exchange. The term national securities exchange shall mean an exchange registered as a national securities exchange under section 6 of the Securities Exchange Act of...

  20. 31 CFR 500.325 - National securities exchange. (United States)


    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false National securities exchange. 500.325... Definitions § 500.325 National securities exchange. The term national securities exchange shall mean an exchange registered as a national securities exchange under section 6 of the Securities Exchange Act of...


    Directory of Open Access Journals (Sweden)

    Manhur Jafarli


    Full Text Available Sorption regularities of Zn2+ and Pb2+ ions from water solutions by ion exchangers of Diaion CR 11, Amberlite IRC 748 with iminodiacetic acid functional group and Dowex M 4195 with bis-picolilamine functional group are investigated, sorption isotherms are plotted, isotherms are analyzed on the basis of known models, thermodynamic parameters are calculated on the basis of kinetic data, thermodynamic factor controlling processes is determined.

  2. Inorganic ion exchangers for nuclear waste remediation

    Energy Technology Data Exchange (ETDEWEB)

    Clearfield, A.; Bortun, A.; Bortun, L.; Behrens, E. [Texas A& M Univ., College Station, TX (United States)


    The objective of this work is to provide a broad spectrum of inorganic ion exchangers that can be used for a range of applications and separations involving remediation of groundwater and tank wastes. The authors intend to scale-up the most promising exchangers, through partnership with AlliedSignal Inc., to provide samples for testing at various DOE sites. While much of the focus is on exchangers for removal of Cs{sup +} and Sr{sup 2+} from highly alkaline tank wastes, especially at Hanford, the authors have also synthesized exchangers for acid wastes, alkaline wastes, groundwater, and mercury, cobalt, and chromium removal. These exchangers are now available for use at DOE sites. Many of the ion exchangers described here are new, and others are improved versions of previously known exchangers. They are generally one of three types: (1) layered compounds, (2) framework or tunnel compounds, and (3) amorphous exchangers in which a gel exchanger is used to bind a fine powder into a bead for column use. Most of these exchangers can be regenerated and used again.

  3. How did China's foreign exchange reform affect the efficiency of foreign exchange market? (United States)

    Ning, Ye; Wang, Yiming; Su, Chi-wei


    This study compares the market efficiency of China's onshore and offshore foreign exchange markets before and after the foreign exchange reform on August 11, 2015. We use the multifractal detrended fluctuation analysis of the onshore and offshore RMB/USD spot exchange rate series as basis. We then find that the onshore foreign exchange market before the reform has the lowest market efficiency, which increased after the reform. The offshore foreign exchange market before the reform has the highest market efficiency, which dropped after the reform. This finding implies the increased efficiency of the onshore foreign exchange market and the loss of efficiency in the offshore foreign exchange market. We also find that the offshore foreign exchange market is more efficient than the onshore market and that the gap shrank after the reform. Changes in intervention of the People's Bank of China since the reform is a possible explanation for the changes in the efficiency of the foreign exchange market.

  4. Phase-exchange thermoacoustic engine (United States)

    Offner, Avshalom; Meir, Avishai; Ramon, Guy Z.; WET Lab Team


    Phase-exchange thermoacoustic engines are reliable machines holding great promise in converting heat from low grade heat sources to mechanical or electrical power. In these engines the working fluid is a gas mixture containing one condensable component, decreasing the temperature difference required for ignition and steady state operation. Our experimental setup consists of a vertical acoustic resonator containing a mixture of air-water vapor. Water evaporates near the heat source, condenses at the heat sink and is drawn back down by gravity and capillary forces where it re-evaporates, sustaining a steady state closed thermodynamic cycle. We investigated the stability limit, namely the critical point at which temperature difference in the engine enables onset of self-excited oscillations, and the steady state of the engine. A simple theoretical model was derived, describing mechanisms of irreversible entropy generation and production of acoustic power in such engines. This model captures the essence in the differences between regular and phase-exchange thermoacoustic engines, and shows good agreement with experimental results of stability limit. Steady state results reveal not only a dramatic decrease in temperature difference, but also an increase in engine performances. The authors acknowledge the support from the Nancy and Stephen Grand Technion Energy Program (GTEP).

  5. Dipole-induced exchange bias. (United States)

    Torres, Felipe; Morales, Rafael; Schuller, Ivan K; Kiwi, Miguel


    The discovery of dipole-induced exchange bias (EB), switching from negative to positive sign, is reported in systems where the antiferromagnet and the ferromagnet are separated by a paramagnetic spacer (AFM-PM-FM). The magnitude and sign of the EB is determined by the cooling field strength and the PM thickness. The same cooling field yields negative EB for thin spacers, and positive EB for thicker ones. The EB decay profile as a function of the spacer thickness, and the change of sign, are attributed to long-ranged dipole coupling. Our model, which accounts quantitatively for the experimental results, ignores the short range interfacial exchange interactions of the usual EB theories. Instead, it retains solely the long range dipole field that allows for the coupling of the FM and AFM across the PM spacer. The experiments allow for novel switching capabilities of long range EB systems, while the theory allows description of the structures where the FM and AFM are not in atomic contact. The results provide a new approach to design novel interacting heterostructures.

  6. Exchange of astronomy teaching experiences (United States)

    Ros, Rosa M.

    The Working Group of the European Association for Astronomy Education responsible for Teacher Training organises an annual Summer School for teachers under expert guidance. For a week the teachers participating can exchange experiences, increase their knowledge and discuss different ideas and perspectives. In general, the instructors are professional astronomers, professors and teachers from different countries. The papers presented offer very practical activities, paying special attention to didactic aspects, and take the form of general lectures to all 40 participants and workshops to reduced groups of 20 participants. There are also day and night observations, without expensive equipment or complicated procedures, that are easy to set up and based on topics that it is possible to use in the classroom. The Summer Schools promote a scientific astronomical education at all levels of astronomy teaching, reinforce the link between professional astronomers and teachers with experience of teaching astronomy, allow debates among the participants on their pedagogical activities already carried out in their own classroom and help them to organise activities outside it. Astronomy teachers need special training, access to specific research, to new educational materials and methods and the opportunity to exchange experiences. All these things are provided by the Summer School.

  7. Sustainable health information exchanges: the role of institutional factors

    National Research Council Canada - National Science Library

    Frankel, Meir; Chinitz, David; Salzberg, Claudia A; Reichman, Katriel


    ... United States.In Israel, the vertically integrated Clalit health services developed a different solution for HIE than was developed in the non-vertically integrated Maccabi and Meuhedet health funds...

  8. Energy and CO $ _2 $; exchanges and influencing factors in spring ...

    Indian Academy of Sciences (India)

    is an important crop for food security in the desert-oasis farmland in the middle reaches of the Heihe River in northwestern China. ... State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, ...

  9. Influence of scale deposit and its thickness on the heat exchanger operational efficiency (United States)

    Kocharyan, E. V.; Skiba, E. D.; Levina, E. Y.


    Materials submitted provide for the research results of the problem of scale formation in heat exchangers and show results of calculations of scale type and thickness impact on heat transfer factor and on heat exchanger overall energy efficiency with regard to heat exchanger hydraulic resistance increase. Calculations have been carried out using the example of heat exchanger PV1 (∏B1) 219-2-G-1, 6-6-UZ, manufactured as per State Standard (GOST) 27590-2005. On the basis of calculations performed recommendations on maximum allowable thickness of scale crust of different type, after scaling of which the heat exchanger operation may infringe the technological process, have been elaborated.

  10. A thermal design method for the performance optimization of multi-stream plate-fin heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhe; Li, Yanzhong [Xi’an Jiaotong University, Xi’an (China); Sunden, Bengt [Lund University, Lund (Sweden); Han, Fenghui [Dalian Maritime University, Dalian (China)


    An optimization design method based on field synergy principle is developed for Multi-stream plate-fin heat exchangers (MPHEs) with a segmented differential model. The heat exchanger is divided into a number of sub-exchangers along the main stream, and each sub-exchanger consists of N passages along the height of the exchanger. Compared with the traditional heat exchanger design, this method allows temperature and pressure fields to be obtained via coupling calculation with consideration of variable physical properties and the axial heat loss of the heat exchanger. Finally, the heat exchanger is optimally designed using a temperature-difference uniformity optimization factor based on field synergy principle. This design model can provide an accurate temperature field and pressure field, because the stream properties are determined by the mean temperature and pressure of each local sub-exchanger. Optimum results indicate that the temperature distribution on the cross section of the heat exchanger is relatively uniform and that the temperature difference of heat transfer for each stream is always a small value. These characteristics prove the feasibility and effectiveness of this design model. In this paper, a case of five stream plate-fin heat exchangers for an ethylene plant is designed under a practical cold box operating condition with the proposed model, the structure and heat transfer of which are optimally determined. The design model and optimization method proposed in this work can provide theoretical and technical support to the optimization design of MPHEs.

  11. DHE (downhole heat exchangers). [Downhole Heat Exchangers (DHE)

    Energy Technology Data Exchange (ETDEWEB)

    Culver, G.


    The use of downhole heat exchangers (DHE) for residential or commercial space and domestic water heating and other applications has several desirable features. Systems are nearly or completely passive -- that is, no or very little geothermal water or steam is produced from the well either reducing or completely eliminating surface environmental concerns and the need for disposal systems or injection wells. Initial cost of pumps and installation are eliminated or reduced along with pumping power costs and maintenance costs associated with pumping often corrosive geothermal fluids. Many residential and small commercial systems do not require circulating pumps because the density difference in the incoming and outgoing sides of the loop are sufficient to overcome circulating friction losses in the entire system. The major disadvantage of DHEs is their dependence on natural heat flow. In areas where geological conditions provide high permeability and a natural hydraulic gradient, DHEs can provide a substantial quantity of heat. A single 500-ft (152 m) well in Klamath Falls, Oregon, supplies over one megawatt thermal and output is apparently limited by the surface area of pipe that can be installed in the well bore. In contrast, DHEs used in conjunction with heat pumps may supply less than 8 KW from a well of similar depth. Here output is limited by conductive heat flow with perhaps a small contribution from convection near the well bore. The highest capacity DHE reported to date, in Turkey, supplies 6 MW thermal from an 820-ft (250 m) well. There were two main goals for this project. The first was to gather, disseminate and exchange internationally information on DHES. The second was to perform experiments that would provide insight into well bore/aquifer interaction and thereby provide more information on which to base DHE designs. 27 refs., 31 figs., 3 tabs.

  12. Gas exchange and chlorophyll a fluorescence parameters of ornamental bromeliads

    Directory of Open Access Journals (Sweden)

    Karina Gonçalves da Silva


    Full Text Available Gas exchange and chlorophyll a fluorescence are widely used in physiological and ecological studies; however, few studies have used these techniques with ornamental plants. This study tested the potential contribution of gas exchange and chlorophyll a fluorescence to evaluate the water and nutrients uptake by the tank and root system of epiphyte bromeliad Guzmania lingulata. For this purpose, we conducted an experiment with different water regime and another with different concentrations of nitrogen. The experiments were: 1 - Watering: Control (application of water into Tank and Root, Tank (watering into Tank, Root (watering Root and Drought (water suspension during the 90 days of experimentation and 2 - Nitrogen: Plants fertilized with Hoagland and Arnon nutrient solution exclusively into Tank or Root with nitrogen concentrations of control and 2.62 or 5.34 mM N applied as urea. The Fv /Fm ratio allowed comparing the treatments between experiments, demonstrating that Root and Tank both have the capacity to maintain G. lingulata photosynthetic activity and growth, while Drought treatment (water suspension was the limiting factor for energy conversion efficiency of PSII. However, gas exchange was more permissive as a parameter for comparing treatments in the nitrogen experiment, providing important information about the general aspects of the photosynthetic process in the watering experiment. Both gas exchange and chlorophyll a fluorescence can support the evaluation of G. lingulata physiological status and can be useful tools in ornamental horticultural studies.

  13. Potential Effects of Horizontal Gene Exchange in the Human Gut

    Directory of Open Access Journals (Sweden)

    Aaron Lerner


    Full Text Available Many essential functions of the human body are dependent on the symbiotic microbiota, which is present at especially high numbers and diversity in the gut. This intricate host–microbe relationship is a result of the long-term coevolution between the two. While the inheritance of mutational changes in the host evolution is almost exclusively vertical, the main mechanism of bacterial evolution is horizontal gene exchange. The gut conditions, with stable temperature, continuous food supply, constant physicochemical conditions, extremely high concentration of microbial cells and phages, and plenty of opportunities for conjugation on the surfaces of food particles and host tissues, represent one of the most favorable ecological niches for horizontal gene exchange. Thus, the gut microbial system genetically is very dynamic and capable of rapid response, at the genetic level, to selection, for example, by antibiotics. There are many other factors to which the microbiota may dynamically respond including lifestyle, therapy, diet, refined food, food additives, consumption of pre- and probiotics, and many others. The impact of the changing selective pressures on gut microbiota, however, is poorly understood. Presumably, the gut microbiome responds to these changes by genetic restructuring of gut populations, driven mainly via horizontal gene exchange. Thus, our main goal is to reveal the role played by horizontal gene exchange in the changing landscape of the gastrointestinal microbiome and potential effect of these changes on human health in general and autoimmune diseases in particular.

  14. Exchange Rate Forecasting Using Entropy Optimized Multivariate Wavelet Denoising Model

    Directory of Open Access Journals (Sweden)

    Kaijian He


    Full Text Available Exchange rate is one of the key variables in the international economics and international trade. Its movement constitutes one of the most important dynamic systems, characterized by nonlinear behaviors. It becomes more volatile and sensitive to increasingly diversified influencing factors with higher level of deregulation and global integration worldwide. Facing the increasingly diversified and more integrated market environment, the forecasting model in the exchange markets needs to address the individual and interdependent heterogeneity. In this paper, we propose the heterogeneous market hypothesis- (HMH- based exchange rate modeling methodology to model the micromarket structure. Then we further propose the entropy optimized wavelet-based forecasting algorithm under the proposed methodology to forecast the exchange rate movement. The multivariate wavelet denoising algorithm is used to separate and extract the underlying data components with distinct features, which are modeled with multivariate time series models of different specifications and parameters. The maximum entropy is introduced to select the best basis and model parameters to construct the most effective forecasting algorithm. Empirical studies in both Chinese and European markets have been conducted to confirm the significant performance improvement when the proposed model is tested against the benchmark models.

  15. Injection risk behavior among women syringe exchangers in San Francisco. (United States)

    Lum, Paula J; Sears, Clare; Guydish, Joseph


    Women who inject drugs in cities where syringe exchange programs (SEPs) are well established may have different risks for HIV infection. In 1997, we interviewed 149 female syringe exchangers in San Francisco, CA, a city with high rates of injection drug use that is home to one of the largest and oldest SEPs in the United States. In this report, we describe their sociodemographics, health, and risk behavior, and we examine factors associated with recent syringe sharing. Fifty percent of respondents were women of color and the median age was 38 years. Most (86%) injected heroin and nearly half were currently homeless or had recently been incarcerated. One-third of all women reported needle sharing in the prior month. This was higher than the rate of needle sharing reported by a mixed gender sample of San Francisco exchangers in 1993, although it resembled the rate reported by a mixed gender sample in 1992. In a multivariate analysis, syringe sharing was associated with age, housing status, and sexual partnerships. Syringe sharers were more likely to be young, homeless, or have a sexual partner who was also an injection drug user. While wide access to sterile syringes is an important strategy to reduce HIV transmission among injection drug users (IDU), syringe exchange alone cannot eradicate risky injection by female IDU. Additional efforts to reduce risky injection practices should focus on younger and homeless female IDU, as well as address selective risk taking between sexual partners.

  16. Needs Assessment for Exchange Students in Taiwan

    Directory of Open Access Journals (Sweden)

    Kentei Takaya


    Full Text Available With the growing mobility of international students in Asia and the Pacific, Taiwan has become actively involved in promoting international academic exchange. This research investigates the experience of exchange students from the Philippines and mainland China and examines their needs while studying in Taiwan. Qualitative in-depth interviews were conducted with exchange students from the Philippines and mainland China. The findings suggest that while exchange students from the Philippines and mainland China both encountered difficulties during their study in Taiwan, exchange students from the Philippines were inclined to encounter more difficulties compared to those from mainland China due to language difficulties. Based on the findings of this study, suggested support services for future exchange students in Taiwan are outlined to match the needs of students from both Chinese and non-Chinese-speaking backgrounds.

  17. Listening to agent agendas in student exchanges

    DEFF Research Database (Denmark)

    Tarp, Gertrud


    The paper is based upon a research study of short-term student exchanges. The study took place from 1996-2000, and comprises seven classes of students from six Danish business schools. Short-term student exchanges in terms of EU funded exchanges and local school exchanges are means to develop...... the students’ understanding of their own cultural background and of foreign cultures. The research study is an attempt to look at internationalisation and student exchanges from a student perspective. Thus the structural aim and the structural framework are considered given elements. The study is based upon...... institutional scepticism and placed within the theoretical framework of symbolic interactionism. The methodology applied is qualitative, grounded theory, and the data originate from diaries, semi-structured interviews and semi-open questionnaires. The findings show that the students have their own exchange...

  18. Incentives and Information Exchange in International Taxation


    Keen, M.; Ligthart, J.E.


    The exchange of taxpayer-specific information between national tax authorities has recently emerged as a key and controversial topic in international tax policy discussions, most notably with the OECD s harmful tax practices project and the EU s savings tax initiative.This paper analyses the effects of information exchange and withholding taxes, recognizing that countries which agree to exchange information do not forfeit the ability to levy withholding taxes, and also focusing in particular ...

  19. Development of nursing students during international exchange


    Varusk, Inge


    The purpose of the study was to gather information about the experiences which nursing exchange students have had when they have been abroad. This aim of this literature review was to evaluates and presents the most current and relevant information of the topic as possible. The findings were divided into two themes – how nursing exchange students had evolved on a personal and on a professional level. Most of the findings were about how the nursing exchange students had evolved on a person...

  20. [Plasma exchange in nephrology: Indications and technique]. (United States)

    Ridel, Christophe; Kissling, Sébastien; Mesnard, Laurent; Hertig, Alexandre; Rondeau, Éric


    Plasma exchange is a non-selective apheresis technique that can be performed by filtration or centrifugation allowing rapid purification of high molecular weight pathogens. An immunosuppressive treatment is generally associated to reduce the rebound effect of the purified substance. Substitution solutes such as human albumin and macromolecules are needed to compensate for plasma extraction. Compensation by viro-attenuated plasma is reserved solely for the treatment of thrombotic microangiopathies or when there is a risk of bleeding, because this product is very allergenic and expensive. The treatment goal for a plasma exchange session should be between one and one and one-half times the patient's plasma volume estimated at 40 mL/kg body weight. The anticoagulation is best ensured by the citrate. Complications of plasma exchange are quite rare according to the French hemapheresis registry. The level of evidence of efficacy of plasma exchange in nephrology varies from one pathology to another. Main indications of plasma exchange in nephrology are Goodpasture syndrome, antineutrophil cytoplasmic antibody vasculitis when plasma creatinine is greater than 500 μmol/L, and thrombotic microangiopathies. During renal transplantation, plasma exchange may be proposed in the context of human leukocyte antigen (HLA) desensitization protocols or ABO-incompatible graft. After renal transplantation, plasma exchange is indicated as part of the treatment of acute humoral rejection or recurrent focal segmental glomerulosclerosis on the graft. Plasma exchanges are also proposed in the management of cryoglobulinemia or polyarteritis nodosa. Hemodialysis with membranes of very high permeability tends to replace plasma exchange for myeloma nephropathy. The benefit from plasma exchange has not been formally demonstrated for the treatment of severe lupus or antiphospholipid antibody syndrome. There is no indication of plasma exchange in the treatment of scleroderma or nephrogenic

  1. Electric control of exchange bias training. (United States)

    Echtenkamp, W; Binek, Ch


    Voltage-controlled exchange bias training and tunability are introduced. Isothermal voltage pulses are used to reverse the antiferromagnetic order parameter of magnetoelectric Cr(2)O(3), and thus continuously tune the exchange bias of an adjacent CoPd film. Voltage-controlled exchange bias training is initialized by tuning the antiferromagnetic interface into a nonequilibrium state incommensurate with the underlying bulk. Interpretation of these hitherto unreported effects contributes to new understanding in electrically controlled magnetism.

  2. China: Exchange Rate Policy and Asian Trade


    Alicia García-Herrero; Tuuli Koivu


    This paper shows empirically that China s trade balance is sensitive to fluctuations in the renminbi real effective exchange rate. However, the current size of the trade surplus is such that exchange rate policy, alone, will probably not be able to address the imbalance. The reduction in the trade surplus is limited mainly because Chinese imports do not react as expected to exchange rate appreciation. In fact, they tend to fall rather than increase. By estimating bilateral import equations fo...

  3. Fluid to fluid contact heat exchanger (United States)

    Clark, W. E.


    Heat transfer and pressure drop test results for a fluid to fluid contact heat exchanger are reported. The heat exchanger, fabricated and tested to demonstrate one method of transferring heat between structures in space, had a total contact area of 0.18 sq m. It utilized contact surfaces which were flexible and conformed to the mating contact surfaces upon pressurization of the fluid circulating within the heat exchanger. During proof-of-concept performance tests, the heat exchanger was operated in a typical earth environment. It demonstrated a contact conductance of 3.8 kW/sq m C at contact pressures in the 15 to 70 kPa range.

  4. Essential Specification Elements for Heat Exchanger Replacement

    Energy Technology Data Exchange (ETDEWEB)

    Bower, L.


    Performance upgrade and equipment degradation are the primary impetuses for a nuclear power plant to engage in the large capital cost project of heat exchanger replacement. Along with attention to these issues, consideration of heat exchanger Codes and Standards, material improvements, thermal redesign, and configuration are essential for developing User’s Design Specifications for successful replacement projects. The User’s Design Specification is the central document in procuring ASME heat exchangers. Properly stated objectives for the heat exchanger replacement are essential for obtaining the materials, configurations and thermal designs best suited for the nuclear power plant. Additionally, the code of construction required and the applied manufacturing standard (TEMA or HEI) affects how the heat exchanger may be designed or configured to meet the replacement goals. Knowledge of how Codes and Standards affect design and configuration details will aid in writing the User’s Design Specification. Joseph Oat Corporation has designed and fabricated many replacement heat exchangers for the nuclear power industry. These heat exchangers have been constructed per ASME Section III to various Code-Years or ASME Section VIII-1 to the current Code-Year also in accordance with TEMA and HEI. These heat exchangers have been a range of like-for-like replacement to complete thermal, material and configuration redesigns. Several examples of these heat exchangers with their Code, Standard and specification implications are presented. (Author.

  5. Ion Exchange and Liquid Column Chromatography. (United States)

    Walton, Harold F.


    Emphasizes recent advances in principles and methodology in ion exchange and chromatography. Two tables list representative examples for inorganic ions and organic compounds. Cites 544 references. (CS)

  6. Entropy exchange for infinite-dimensional systems. (United States)

    Duan, Zhoubo; Hou, Jinchuan


    In this paper the entropy exchange for channels and states in infinite-dimensional systems are defined and studied. It is shown that, this entropy exchange depends only on the given channel and the state. An explicit expression of the entropy exchange in terms of the state and the channel is proposed. The generalized Klein's inequality, the subadditivity and the triangle inequality about the entropy including infinite entropy for the infinite-dimensional systems are established, and then, applied to compare the entropy exchange with the entropy change.

  7. Micro tube heat exchangers for Space Project (United States)

    National Aeronautics and Space Administration — Mezzo fabricates micro tube heat exchangers for a variety of applications, including aerospace, automotive racing, Department of Defense ground vehicles, economizers...

  8. Foreign Exchange Risk in International Transactions

    Directory of Open Access Journals (Sweden)

    Florentina-Olivia Balu


    In this article we will focus on forward and futures contracts for managing foreign exchange risk. A forward is a contract to buy or sell currency at an agreed upon exchange rate at a specific date in the future. Futures are similar to forwards except that they’re traded on exchanges which specify settlement dates. Also we make some recommendations related to the foreign exchange risk-management practices that are useful for companies involved in international trade and for financial institutions interested in providing hedging products to these companies.

  9. Data Exchange Management Information System (DEMIS) (United States)

    Social Security Administration — DEMIS combines a database (Operational Data Store - ODS) of data exchange-related Management Information (MI) with the agency's querying and reporting utility, the...

  10. Health and sexual behaviour among exchange students. (United States)

    Petersson, Carina; Peterson, Ulla; Swahnberg, Katarina; Oscarsson, Marie


    The objective was to describe the exchange students' health and sexual behaviour associated with their exchange studies, and examine the extent to which they had received preventive efforts against human immunodeficiency virus (HIV)/sexually transmitted infection (STI) and safer sex before departure. A cross-sectional study was conducted based on a web survey with questions about sexual behaviour, self-esteem and psychological well-being. Data were analysed using descriptive and analytical statistics. A total of 136 outgoing exchange students from a Swedish University participated. Most of the exchange students rated their health as good, had psychological well-being and rated their self-esteem as being high. Approximately half of the exchange students had sex with a new partner during the exchange semester, and 87% of them had sexually risky behaviour. More than half (61%) of the exchange students had received preventive efforts before departure. No statistically significant difference regarding preventive information was found between those who reported sexually risky behaviour and those who did not. The group that had sexually risky behaviour desired free condoms and access to clinics for sexual health. CONCLUSIONS EXCHANGE STUDENTS RATED THEIR HEALTH AS GOOD, AND THE MAJORITY OF THEM PARTICIPATED IN INFORMATION SESSIONS THAT ADDRESSED PREVENTIVE EFFORTS ON HIV/STI AND SAFER SEX BEFORE DEPARTURE SEXUALLY RISKY BEHAVIOUR DURING EXCHANGE STUDIES WAS REPORTED AND HIGHLIGHTS THE NEED FOR MORE EFFECTIVE PREVENTIVE MEASURES; FOR EXAMPLE, A RECOLLECTION OF READING STI INFORMATION. © Author(s) 2016.

  11. Exchange effects in a cold plasma

    CERN Document Server

    Ekman, Robin; Brodin, Gert


    We have studied the exchange corrections to linear electrostatic wave propagation in a plasma using a quantum kinetic formalism. Specifically we have considered the zero temperature limit. In order to simplify the calculations we have focused on the long wavelength limit, i.e. wavelengths much longer than the de Broglie wavelength. For the case of ion-acoustic waves we have calculated the exchange correction both to the damping rate and the real part of the frequency. For Langmuir waves the frequency shift due to exchange effects is found. Our results are compared with the frequency shifts deduced from commonly used exchange potentials which are computed from density functional theory.

  12. Microchannel Heat Exchangers with Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Y.; Ohadi, M.M.; Radermacher, R.


    significantly. However, under such conditions, air side pressure drop also increases when moisture condensation occurs. An increase in airflow rate also increases the overall heat transfer coefficient. Air side pressure drop mainly depends on airflow rate. For the gas cooler, a significant portion of the heat transfer occurred in the first heat exchanger module on the refrigerant inlet side. The temperature and pressure of CO{sub 2} significantly affect the heat transfer and fluid flow characteristics due to some important properties (such as specific heat, density, and viscosity). In the transcritical region, performance of CO{sub 2} strongly depends on the operating temperature and pressure. Semi-empirical models were developed for predictions of CO{sub 2} evaporator and gas cooler system capacities. The evaporator model introduced two new factors to account for the effects of air-side moisture condensate and refrigerant outlet superheat. The model agreed with the experimental results within {+-}13%. The gas cooler model, based on non-dimensional parameters, successfully predicted the experimental results within {+-}20%. Recommendations for future work on this project include redesigning headers and/or introducing flow mixers to avoid flow mal-distribution problems, devising new defrosting techniques, and improving numerical models. These recommendations are described in more detail at the end of this report.

  13. Performance evaluation on an air-cooled heat exchanger for alumina nanofluid under laminar flow. (United States)

    Teng, Tun-Ping; Hung, Yi-Hsuan; Teng, Tun-Chien; Chen, Jyun-Hong


    This study analyzes the characteristics of alumina (Al2O3)/water nanofluid to determine the feasibility of its application in an air-cooled heat exchanger for heat dissipation for PEMFC or electronic chip cooling. The experimental sample was Al2O3/water nanofluid produced by the direct synthesis method at three different concentrations (0.5, 1.0, and 1.5 wt.%). The experiments in this study measured the thermal conductivity and viscosity of nanofluid with weight fractions and sample temperatures (20-60°C), and then used the nanofluid in an actual air-cooled heat exchanger to assess its heat exchange capacity and pressure drop under laminar flow. Experimental results show that the nanofluid has a higher heat exchange capacity than water, and a higher concentration of nanoparticles provides an even better ratio of the heat exchange. The maximum enhanced ratio of heat exchange and pressure drop for all the experimental parameters in this study was about 39% and 5.6%, respectively. In addition to nanoparticle concentration, the temperature and mass flow rates of the working fluid can affect the enhanced ratio of heat exchange and pressure drop of nanofluid. The cross-section aspect ratio of tube in the heat exchanger is another important factor to be taken into consideration.

  14. Algorithms for Lightweight Key Exchange. (United States)

    Alvarez, Rafael; Caballero-Gil, Cándido; Santonja, Juan; Zamora, Antonio


    Public-key cryptography is too slow for general purpose encryption, with most applications limiting its use as much as possible. Some secure protocols, especially those that enable forward secrecy, make a much heavier use of public-key cryptography, increasing the demand for lightweight cryptosystems that can be implemented in low powered or mobile devices. This performance requirements are even more significant in critical infrastructure and emergency scenarios where peer-to-peer networks are deployed for increased availability and resiliency. We benchmark several public-key key-exchange algorithms, determining those that are better for the requirements of critical infrastructure and emergency applications and propose a security framework based on these algorithms and study its application to decentralized node or sensor networks.

  15. Monetary Exchange with Multilateral Matching

    DEFF Research Database (Denmark)

    Julien, Benoît; Kennes, John; King, Ian

    This paper analyzes monetary exchange in a search model allowing for multilateral matches to be formed, according to a standard urn-ballprocess. We consider three physical environments: indivisible goods and money, divisible goods and indivisible money, and divisible goods and money. We compare....... In particular, surplus maximization can be achieved in this setting, in equilibrium, with a positive money supply. Moreover, with flexible prices and directed search, the first best allocation can be attained through price posting or through auctions with lotteries, but not through auctions without lotteries....... Finally, analysis of the case of divisible goods and money can be performed without the assumption of large families (as in Shi (1997)) or the day and night structure of Lagos and Wright (2005)....

  16. Educational Exchanges Across the Equator (United States)

    Norman, D. J.; Walker, C. E.; Smith, M.; Pompea, S. M.; Orellana, D.


    What is color? What is light? How can we use a spectrometer to help students understand the answers to these questions? Even half a world apart and between people of different languages and cultures, how to teach these ideas to students can be a lively subject for discussion. And it is! Aided by Internet 2-based videoconferencing, NOAO North and South have sponsored three teacher professional development videoconference workshops, dubbed ASTRO-Chile, linking teachers in Tucson, AZ, and La Serena, Chile. The teachers exchange methods and ideas about how to explain and demonstrate physical concepts, important to the study of astronomy, to students of various ages. The workshops are conducted in Spanish with four bilingual science teachers from the Tucson area discussing pedagogical approaches with their teaching counterparts in Chile. Demonstrations and project presentations, from both sites, are included as part of each workshop. This work is supported, in part, through funding from the NSF Astronomy and Astrophysics Postdoctoral Fellowship.

  17. Exchanger system for anhydrite pipeline

    Energy Technology Data Exchange (ETDEWEB)

    Penet, A.


    This paper deals with the problem of roadway behaviour affecting airways, bottom roads and top roads in advancing faces in the HBNPC area. The support work in these zones used to be undertaken manually and involved a lot of man hours. These operations are now mechanized in the form of pneumatic stowing with anhydrite. The latter is delivered by pipeline using compressed air. The 'exchanger' is a sort of branching system in the pipeline enabling the flow to be switched from the top end of the face to the bottom end and vice versa (diagram). The associated operations can be undertaken with ease. The effect the system has on costs will soon be known. (In French)

  18. Evaluation of the thermal effect on separation selectivity in anion-exchange processes using superheated water ion-exchange chromatography. (United States)

    Shibukawa, Masami; Taguchi, Akihiko; Suzuki, Yusuke; Saitoh, Kazunori; Hiaki, Toshihiko; Yarita, Takashi


    The thermal effect on retention and separation selectivity of inorganic anions and aromatic sulfonate ions in anion-exchange chromatography is studied on a quaternized styrene-divinylbenzene copolymer anion-exchange column in the temperature range of 40-120 °C using superheated water chromatography. The selectivity coefficient for a pair of identically charged anions approaches unity as temperature increases provided the ions have the same effective size, such that the retention of an analyte ion decreases with an increase in temperature when the analyte ion has stronger affinity for the ion-exchanger than that of the eluent counterion, whereas it increases when it has weaker affinity. The change in anion-exchange selectivity with temperature observed with superheated water chromatography has been discussed on the basis of the effect of temperature on hydration of the ions. At elevated temperatures, especially in superheated water, the electrostatic interaction or association of the ions with the fixed ion in the resin phase becomes a predominant factor resulting in a different separation selectivity from that obtained at ambient temperature.

  19. Modelling boreal forest CO{sub 2} exchange and seasonality

    Energy Technology Data Exchange (ETDEWEB)

    Thum, T.


    Man-induced climate change has raised the need to predict the future climate and its feedback to vegetation. These are studied with global climate models; to ensure the reliability of these predictions, it is important to have a biosphere description that is based upon the latest scientific knowledge. This work concentrates on the modelling of the CO{sub 2} exchange of the boreal coniferous forest, studying also the factors controlling its growing season and how these can be used in modelling. In addition, the modelling of CO{sub 2} gas exchange at several scales was studied. A canopy-level CO{sub 2} gas exchange model was developed based on the biochemical photosynthesis model. This model was first parameterized using CO{sub 2} exchange data obtained by eddy covariance (EC) measurements from a Scots pine forest at Sodankylae. The results were compared with a semi-empirical model that was also parameterized using EC measurements. Both of the models gave satisfactory results. The biochemical canopy-level model was further parameterized at three other coniferous forest sites located in Finland and Sweden. At all the sites, the two most important biochemical model parameters showed seasonal behaviour, i.e., their temperature responses changed according to the season. Modelling results were improved when these changeover dates were related to temperature indices. During summer-time the values of the biochemical model parameters were similar at all the four sites. Different control factors for CO{sub 2} gas exchange were studied at the four coniferous forests, including how well these factors can be used to predict the initiation and cessation of the CO{sub 2} uptake. Temperature indices, atmospheric CO{sub 2} concentration, surface albedo and chlorophyll fluorescence (CF) were all found to be useful and have predictive power. In Finnish Lapland a trend toward an earlier start of the CO{sub 2} uptake in spring was also observed. In addition, a detailed simulation study

  20. Comparative study of Nusselt number for a single phase fluid flow using plate heat exchanger

    Directory of Open Access Journals (Sweden)

    Shanmugam Rajasekaran


    Full Text Available In this study, the plate heat exchangers are used for various applications in the industries for heat exchange process such as heating, cooling and condensation. The performance of plate heat exchanger depends on many factors such as flow arrangements, plate design, chevron angle, enlargement factor, type of fluid used, etc. The various Nusselt number correlations are developed by considering that the water as a working fluid. The main objective of the present work is to design the experimental set-up for a single phase fluid flow using plate heat exchanger and studied the heat transfer performance. The experiments are carried out for various Reynolds number between 500 and 2200, the heat transfer coefficients are estimated. Based on the experimental results the new correlation is developed for Nusselt number and compared with an existing correlation.

  1. Analysis of Heat Transfers inside Counterflow Plate Heat Exchanger Augmented by an Auxiliary Fluid Flow (United States)

    Khaled, A.-R. A.


    Enhancement of heat transfers in counterflow plate heat exchanger due to presence of an intermediate auxiliary fluid flow is investigated. The intermediate auxiliary channel is supported by transverse conducting pins. The momentum and energy equations for the primary fluids are solved numerically and validated against a derived approximate analytical solution. A parametric study including the effect of the various plate heat exchanger, and auxiliary channel dimensionless parameters is conducted. Different enhancement performance indicators are computed. The various trends of parameters that can better enhance heat transfer rates above those for the conventional plate heat exchanger are identified. Large enhancement factors are obtained under fully developed flow conditions. The maximum enhancement factors can be increased by above 8.0- and 5.0-fold for the step and exponential distributions of the pins, respectively. Finally, counterflow plate heat exchangers with auxiliary fluid flows are recommended over the typical ones if these flows can be provided with the least cost. PMID:24719572

  2. Analysis of heat transfers inside counterflow plate heat exchanger augmented by an auxiliary fluid flow. (United States)

    Khaled, A-R A


    Enhancement of heat transfers in counterflow plate heat exchanger due to presence of an intermediate auxiliary fluid flow is investigated. The intermediate auxiliary channel is supported by transverse conducting pins. The momentum and energy equations for the primary fluids are solved numerically and validated against a derived approximate analytical solution. A parametric study including the effect of the various plate heat exchanger, and auxiliary channel dimensionless parameters is conducted. Different enhancement performance indicators are computed. The various trends of parameters that can better enhance heat transfer rates above those for the conventional plate heat exchanger are identified. Large enhancement factors are obtained under fully developed flow conditions. The maximum enhancement factors can be increased by above 8.0- and 5.0-fold for the step and exponential distributions of the pins, respectively. Finally, counterflow plate heat exchangers with auxiliary fluid flows are recommended over the typical ones if these flows can be provided with the least cost.

  3. Noise suppression and long-range exchange coupling for gallium arsenide spin qubits

    DEFF Research Database (Denmark)

    Malinowski, Filip

    of the qubit splitting with respect to gate voltages. We show that for singlet-triplet and resonant exchange qubit this can be achieved by operating a quantum dot array in a highly symmetric configuration. The symmetrization approach results in a factor-of-six improvement of the double dot singlet......-triplet exchange oscillations quality factor while the dephasing times for the threeelectron resonant exchange qubit are marginally longer. Second, we present the study of the Overhauser field noise arising due to interaction with the nuclear spin bath. We show that the Overhauser field noise conforms to classical...... dot in nine different charge occupancies and identify ground state spin in all cases. For even-occupied spin-1/2 multielectron quantum dot a variation of the gate voltage by a few milivolts in the vicinity of the charge transition leads to sign change of the exchange interaction with a single...

  4. Influence on Heat Transfer Coefficient of Heat Exchanger by Velocity and Heat Transfer Temperature Difference

    Directory of Open Access Journals (Sweden)

    WANG Fang


    Full Text Available Aimed to insufficient heat transfer of heat exchanger, research the influence on the heat transfer coefficient impacted by velocity and heat transfer temperature difference of tube heat exchanger. According to the different heat transfer temperature difference and gas velocity,the experimental data were divided into group. Using the control variable method,the above two factors were analyzed separately. K一△T and k一:fitting curve were clone to obtain empirical function. The entire heat exchanger is as the study object,using numerical simulation methods,porous media,k一£model,second order upwind mode,and pressure一velocity coupling with SIMPLE algorithm,the entire heat exchanger temperature field and the heat transfer coefficient distribution were given. Finally the trend of the heat transfer coefficient effected by the above two factors was gotten.

  5. Exchange Rate Policy in Morocco and Persistence of Real Exchange Rate Misalignments

    National Research Council Canada - National Science Library

    Mohamed Bouzahzah; Radouane Bachar


    .... The objective of this article is to highlight the persistent nature of misalignments of the real exchange rate of the Dirham, especially since the adoption by Morocco of a policy exchange rate based...

  6. Review of shell-and-tube heat exchanger fouling and corrosion in geothermal power plant service

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, P.F. II


    Heat exchangers for hot geofluid/working substance vaporizers for binary power plants are considered. A brief description of the physical test apparatus and the geofluid chemistry for each of the several heat exchanger tests is presented. The fouling data developed from these tests are summarized, in most cases presenting a mathematical expression for the increase in fouling factor with time. The materials performance data developed from these same tests are explored. The performance of shell-and-tube heat exchangers used as condensers and ancillary coolers in the power plant heat rejection system is considered.

  7. The exchange rate managements in crisis-experienced emerging market economies after the 1990s


    Taguchi, Hiroyuki


    This article examined the exchange rate managements in the crisis-experienced emerging market economies after the 1990s. First, we found that the exchange rate flexibility has increased from the pre-crisis period towards the post-crisis period under the “soft peg” regime. Second, we identified a structural change in the factors for determining a reference rate in exchange rate management from the pre-crisis period to the post-crisis period. Third, we found that East Asian countries, in their ...

  8. The two-photon exchange contribution to elastic electron-nucleon scattering at large momentum transfer

    Energy Technology Data Exchange (ETDEWEB)

    Andrei V. Afanasev; Stanley J. Brodsky; Carl E. Carlson; Yu-Chun Chen; Marc Vanderhaeghen


    We estimate the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer by using a quark-parton representation of virtual Compton scattering. We thus can relate the two-photon exchange amplitude to the generalized parton distributions which also enter in other wide angle scattering processes. We find that the interference of one- and two-photon exchange contribution is able to substantially resolve the difference between electric form factor measurements from Rosenbluth and polarization transfer experiments.

  9. Land-use change arising from rural land exchange: an agent-based simulation model


    Martha M. Bakker; Alam, Shah Jamal; van Dijk, Jerry; Rounsevell, Mark D A


    Land exchange can be a major factor driving land-use change in regions with high pressure on land, but is generally not incorporated in land-use change models. Here we present an agent-based model to simulate land-use change arising from land exchange between multiple agent types representing farmers, nature organizations, and estate owners. The RULEX model (Rural Land EXchange) was calibrated and applied to a 300 km(2) case study area in the east of the Netherlands. Decision rules about whic...

  10. Exchange Rate Pass Throught: an Analysis for the Costarican Economy from 1991 to 2001


    Leon, Jorge; Morera, Ana Patricia; Ramos, Welmer


    This paper estimates a coefficient of pass through for Costa Rica and tries to determine the importance of some factors that had been pointed out by several empiric studies as probable determinants (GDP gap, real exchange rate deviation from equilibrium, economy openness, and inflationary lag). The coefficient is estimated by OLS. In order to estimate the dynamic between exchange rate and inflation rate a VAR analysis is conducted. In the short run the pass through coefficient is 16% with two...

  11. Social Exchange and Sexual Behavior in Young Women’s Premarital Relationships in Kenya


    Luke, Nancy; Goldberg, Rachel E.; Mberu, Blessing U.; Zulu, Eliya M.


    Transactional sex, or the exchange of money and gifts for sexual activities within nonmarital relationships, has been widely considered a contributing factor to the disproportionate prevalence of HIV/AIDS among young women in sub-Saharan Africa. This study applied social exchange theory to premarital relationships in order to investigate the linkages between a variety of young women’s resources—including employment and material transfers from male partners—and sexual behaviors. Data on the fi...

  12. Switching field of partially exchange-coupled particles (United States)

    Oliva, M. I.; Bertorello, H. R.; Bercoff, P. G.


    The magnetization reversal of partially exchange-coupled particles is studied in detail. The starting point is the observation of a complicated phenomenology in the irreversible susceptibility and FORC distribution functions of Ba hexaferrite samples obtained by means of different sintering conditions. Several peaks in the first-order reversal curve (FORC) distribution functions were identified and associated with clusters with different number of particles. The switching fields of these clusters were related to an effective anisotropy constant Keff that depends on the number of particles in the cluster. Keff is linked to the exchange-coupled volume between two neighboring particles and as a weighted mean between the anisotropy constants of the coupled and uncoupled volumes. By using the modified Brown's equation αex=0.322 is obtained. In order to interpret these results, the switching field of a two-particle system with partial exchange coupling is studied. It is assumed that the spins reorientation across the contact plane between the particles is like a Bloch wall. The energy of the system is written in terms of the fraction of volume affected by exchange coupling and the switching fields for both particles are calculated. At small interaction volume fraction each particle inverts its magnetization independently from the other. As the fraction of exchange-coupled volume increases, cooperative effects appear and the two particles invert their magnetization in a cooperative way. The proposed model allows to interpret for the first time the empirical factor αex in terms of physical arguments and also explain the details observed in the FORC distribution function.

  13. Flow and heat transfer enhancement in tube heat exchangers (United States)

    Sayed Ahmed, Sayed Ahmed E.; Mesalhy, Osama M.; Abdelatief, Mohamed A.


    The performance of heat exchangers can be improved to perform a certain heat-transfer duty by heat transfer enhancement techniques. Enhancement techniques can be divided into two categories: passive and active. Active methods require external power, such as electric or acoustic field, mechanical devices, or surface vibration, whereas passive methods do not require external power but make use of a special surface geometry or fluid additive which cause heat transfer enhancement. The majority of commercially interesting enhancement techniques are passive ones. This paper presents a review of published works on the characteristics of heat transfer and flow in finned tube heat exchangers of the existing patterns. The review considers plain, louvered, slit, wavy, annular, longitudinal, and serrated fins. This review can be indicated by the status of the research in this area which is important. The comparison of finned tubes heat exchangers shows that those with slit, plain, and wavy finned tubes have the highest values of area goodness factor while the heat exchanger with annular fin shows the lowest. A better heat transfer coefficient ha is found for a heat exchanger with louvered finned and thus should be regarded as the most efficient one, at fixed pumping power per heat transfer area. This study points out that although numerous studies have been conducted on the characteristics of flow and heat transfer in round, elliptical, and flat tubes, studies on some types of streamlined-tubes shapes are limited, especially on wing-shaped tubes (Sayed Ahmed et al. in Heat Mass Transf 50: 1091-1102, 2014; in Heat Mass Transf 51: 1001-1016, 2015). It is recommended that further detailed studies via numerical simulations and/or experimental investigations should be carried out, in the future, to put further insight to these fin designs.

  14. The Kuroshio exchange with the South and East China Seas

    Directory of Open Access Journals (Sweden)

    T. Matsuno


    Full Text Available The Kuroshio flows along the edges of the marginal East Asian seas such as the South China Sea (SCS and East China Sea (ECS. Exchanges of materials and energy between the Kuroshio and the marginal seas partly control the environments of the marginal seas. In particular, saline water from the Kuroshio maintains certain salinity in the shelf water in the ECS. Nutrients from the subsurface of the Kuroshio may influence primary production on the shelf. We summarize how the Kuroshio comes into contact with the shelf water or marginal seas, describing phenomena related to the exchange between the Kuroshio and the ECS along with the SCS, using reports in the literature along with original data. The Kuroshio tends to intrude into the SCS through the Luzon Strait in various manners such as direct intrusion, associated with eddies and as a loop current. The Kuroshio intrusion into the shelf region of the ECS has distinct seasonal variation and the Taiwan Warm Current plays a significant role in the determination of water properties in the outer shelf associated with the Kuroshio intrusion. We then examine physical processes related to the interaction between the Kuroshio and shelf water. Interaction between the Kuroshio and the bottom topography is an important process in the control of the exchange around the shelf break. Vertical mixing and frontal eddies are also important factors that control the water exchange and formation of water masses in the outer shelf. Wind stress plays a significant role in the exchange with a rather event-like manner. To determine the source of the water masses, chemical tracers could be powerful tools and it is suggested that a significant part of the shelf water consists of Kuroshio intermediate water.

  15. Foreign exchange transaction exposure of enterprises in Serbia

    Directory of Open Access Journals (Sweden)

    Bogićević Jasmina


    Full Text Available Enterprises involved in international business face transaction exposure to foreign exchange risk. This type of exposure occurs when an enterprise trades, borrows, or lеnds in foreign currency. Transaction exposure has a direct effect on an enterprise’s financial position and profitability. It is one of the three forms of exposure to exchange rate fluctuations, the other two being translation exposure and operating exposure. The aim of this paper is to assess the transaction exposure of enterprises in Serbia operating internationally. In addition to identifying and measuring transaction exposure, this paper explores the practical importance that enterprises in Serbia attach to management of this type of foreign exchange risk. We do not find significant differences between domestic and foreign enterprises in their choice of the type of foreign exchange risk exposure to manage. Although transaction exposure is the most managed type of foreign exchange risk, research has shown that, compared to foreign businesses, Serbian enterprises do not use sufficient protective measures to minimize the negative impact of this type of exposure on their cash flows and profitability. We expected that there would be a statistically significant dependence between the volume of enterprises’ foreign currency transactions and the level of applied transaction exposure management practices. However, the results of our research, based on a sample of enterprises in Serbia operating internationally, show that transaction exposure management practices can be influenced by factors other than the level of an enterprise’s foreign currency transactions, such as the enterprise’s country of origin.

  16. 76 FR 25774 - Determination of Foreign Exchange Swaps and Foreign Exchange Forwards Under the Commodity... (United States)


    ... exchange derivatives, such as foreign exchange options, currency swaps, or non-deliverable forwards (``NDFs... markets for derivative instruments. In general, the payment obligations on currency swaps, interest rate... derivatives. Foreign exchange options, currency swaps, and NDFs may not be exempted from the CEA's definition...

  17. Interest Rate Rules, Exchange Market Pressure, and Successful Exchange Rate Management

    NARCIS (Netherlands)

    Klaassen, F.; Mavromatis, K.


    Central banks with an exchange rate objective set the interest rate in response to what they call ''pressure.'' Instead, existing interest rate rules rely on the exchange rate minus its target. To stay closer to actual policy, we introduce a rule that uses exchange market pressure (EMP), the

  18. Exchange Studies as Actor-Networks: Following Korean Exchange Students in Swedish Higher Education (United States)

    Ahn, Song-ee


    This article explores how Korean exchange students organized their studies during exchange programs in Swedish higher education. For most students, the programs became a disordered period in relation to their education. The value of exchange studies seems mainly to be extra-curricular. Drawing upon actor network theory, the article argues that the…

  19. 77 FR 24752 - Self-Regulatory Organizations; EDGA Exchange, Inc.; EDGX Exchange, Inc.; International Securities... (United States)


    ... COMMISSION [Release No. 34-66834; File Nos. SR-EDGA-2012-08; SR-EDGX-2012-07; SR- ISE-2012-21] Self... Exchange AG Will Transfer Its Interest in ISE Holdings, Inc. to a Newly Formed Swiss Corporation, Eurex... (``EDGA''), EDGX Exchange, Inc. (``EDGX''), International Securities Exchange, LLC (``ISE'' and, with EDGA...

  20. Knowledge sharing in virtual communities: A social exchange theory perspective

    Directory of Open Access Journals (Sweden)

    Li Jinyang


    Full Text Available Purpose: The author tried to identify the knowledge sharing behaviors on the internet, using structural equation modeling methods, proposing a model based on social exchange theory in which share willingness, trust, reciprocity, altruism tended to have impact on people’s knowledge sharing behaviors in virtual communities. Design/methodology/approach: We presented an empirical research which integrated social exchange theory and structural equation modeling methods to analyze several important factors influencing members’ knowledge sharing behaviors in virtual communities. Findings: We analyzed the knowledge sharing behaviors in virtual communities. We found that members’ altruism can not predict knowledge sharing behaviors. We also found that members’ sharing willingness is the most important factor on virtual community knowledge sharing behaviors compared with trust, reciprocity and altruism. Originality/value: From the perspective of social exchange theory, we did empirical test and verified the proposed research model by using structural equation modeling methods. Our finding can help recognize people’s incentive about knowledge sharing.

  1. Heat Exchanger Lab for Chemical Engineering Undergraduates (United States)

    Rajala, Jonathan W.; Evans, Edward A.; Chase, George G.


    Third year chemical engineering undergraduate students at The University of Akron designed and fabricated a heat exchanger for a stirred tank as part of a Chemical Engineering Laboratory course. The heat exchanger portion of this course was three weeks of the fifteen week long semester. Students applied concepts of scale-up and dimensional…

  2. Assessing heat exchanger performance data using temperature ...

    African Journals Online (AJOL)

    To ensure operation of heat exchangers, the goal is to verify that the exchanger is performing, or will perform, at its design. This is especially relevant to coolers that typically operate at heat loads reduced from their design basis. In addition, any calculated performance acceptance criteria must also consider uncertainty and ...

  3. Identifying the weights in exchange market pressure

    NARCIS (Netherlands)

    Klaassen, F.


    Exchange market pressure (EMP) measures the pressure on a currency to depreciate, and it is particularly relevant in crisis periods. EMP adds to the actual depreciation a weighted combination of policy instruments used to ward off depreciation, such as interest rates and foreign exchange

  4. The Story of Foreign Trade and Exchange. (United States)

    Fan, Cedric

    This comic-style booklet is one of a series of educational booklets published by the Federal Reserve Bank of New York. The booklet uses everyday language and lively illustrations to explain the benefits of international trade; the effects of tariffs and quotas; the significance of foreign exchange rates; how the foreign exchange market facilities…

  5. Timing matters in foreign exchange markets (United States)

    Hirata, Yoshito; Aihara, Kazuyuki


    We show using nonlinear time series analysis that the timing of trades in foreign exchange markets has significant information. We apply a set of methods for analyzing point process data developed in neuroscience and nonlinear science. Our results imply that foreign exchange markets might be chaotic and have short-term predictability.

  6. Individual Differences in Reactions to Inequitable Exchanges. (United States)

    Ellis, Barbara B.; Penner, Louis A.


    Investigates the role of sociopathic tendencies in reactions to inequitable exchanges in 273 males and females classified as high or low in sociopathy. Subjects read narratives of inequitable exchanges and assumed the role of the exploiter and the role of the victim in each. (Author/RH)

  7. Synthesis, characterization and ion exchange properties of ...

    Indian Academy of Sciences (India)

    The material has been characterized on the basis of chemical composition, pH titration, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis. The effect on the exchange capacity of drying the exchanger at different temperatures has been studied. The analytical importance of the material has been ...

  8. 22 CFR 41.62 - Exchange visitors. (United States)


    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Exchange visitors. 41.62 Section 41.62 Foreign Relations DEPARTMENT OF STATE VISAS VISAS: DOCUMENTATION OF NONIMMIGRANTS UNDER THE IMMIGRATION AND... intends to participate, in an exchange visitor program designated by the Bureau of Education and Cultural...

  9. Intersite Coulomb interaction and Heisenberg exchange

    NARCIS (Netherlands)

    Eder, R; van den Brink, J.; Sawatzky, G.A


    Based on exact diagonalization results for small clusters we discuss the effect of intersite Coulomb repulsion in Mott-Hubbard or charge transfers insulators. Whereas the exchange constant J for direct exchange is enhanced by intersite Coulomb interaction, that for superexchange is suppressed. The

  10. Exchange Rate Deregulation and Industrial Performance: An ...

    African Journals Online (AJOL)

    The study found that a long-run relationship exists between the industrial productivity growth rate, ration of industrial production to gross domestic product, exchange rate, interest rate and terms of trade, and that exchange rate deregulation has significant impact on industrial performance. In order to determine the short term ...

  11. Are Student Exchange Programs Worth It? (United States)

    Messer, Dolores; Wolter, Stefan C.


    The number of university students participating in exchange programs has risen sharply over the last decade. A survey of Swiss university graduates (classes of 1999 and 2001) shows that participation in student exchange programs depends significantly on the socio-economic background of students. We further analyze whether the participants benefit…

  12. 76 FR 33993 - Exchange Visitor Program (United States)


    ... due to this employment and accordingly, such students will be deemed to be in valid J-1 Exchange... Part 62 RIN 1400-ZA20 Exchange Visitor Program AGENCY: Department of State. ACTION: Notice of... Libyan students. This action is necessary to mitigate the adverse impact upon these students due to...

  13. Pan-American Teletandem Language Exchange Project (United States)

    Castillo-Scott, Aurora


    This paper describes a TeleTandem language exchange project between English speaking Spanish students at Georgia College, USA, and Spanish speaking English students at Universidad de Concepción, Chile. The aim of the project was to promote linguistic skills and intercultural competence through a TeleTandem exchange. Students used Skype and Google…

  14. Ion exchange in the nuclear industry

    Energy Technology Data Exchange (ETDEWEB)

    Bibler, J.P.


    Ion exchange is used in nearly every part of the nuclear fuel cycle -- from the purification of uranium from its ore to the final recovery of uranium and transmutation products. Ion exchange also plays a valuable role in the management of nuclear wastes generated in the fuel cycle.

  15. Ion exchange in the nuclear industry

    Energy Technology Data Exchange (ETDEWEB)

    Bibler, J.P.


    Ion exchange is used in nearly every part of the nuclear fuel cycle -- from the purification of uranium from its ore to the final recovery of uranium and transmutation products. Ion exchange also plays a valuable role in the management of nuclear wastes generated in the fuel cycle.

  16. Staff Exchange or Legal Alien Programs

    DEFF Research Database (Denmark)

    Jørgensen, Rune Nørgaard


    SRA would very much like to support the exchange of best practice between members throughout the year and the Membership Committee is presently looking into the opportunities for a Staff Exchange or Legal Alien Program. However the International Section has already had the chance to provide...

  17. Synthesis, characterization and ion exchange properties of ...

    Indian Academy of Sciences (India)

    zirconium(IV) oxychloride. Its ion exchange capacity for Na+ and K+ was found to be 2⋅20 and 2⋅35 meq g–1 dry exchanger, respectively. The material has been characterized on the basis of chemical composition, pH titration, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis. The effect on the.

  18. Anion exchange membrane design for reverse electrodialysis

    NARCIS (Netherlands)

    Güler, E.


    Reverse electrodialysis (RED) is a clean, sustainable technology for the generation of energy from the mixing of solutions with different salinity. The ion exchange membranes are key elements in RED. Especially the study of anion exchange membranes is crucial since limited research has been done

  19. Microsoft Exchange Server PowerShell cookbook

    CERN Document Server

    Andersson, Jonas


    This book is for messaging professionals who want to build real-world scripts with Windows PowerShell 5 and the Exchange Management Shell. If you are a network or systems administrator responsible for managing and maintaining Exchange Server 2013, you will find this highly useful.

  20. Thermal and hydrodynamic considerations of ice slurry in heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Bedecarrats, Jean-Pierre; Strub, Francoise; Peuvrel, Christophe [Laboratoire de Thermique, Energetique et Procedes, Equipe Energetique, Universite de Pau et des Pays de l' Adour, Avenue de l' Universite, BP 1155, 64013 Pau Cedex (France)


    This article focuses on the behavior in heat exchangers of an ice slurry composed of fine ice particles inside an ethanol-water solution. The heat transfer and friction characteristics were studied in two double pipe heat exchangers, one with a smooth surface and another with an improved surface. Heat transfer coefficients and pressure drops were experimentally investigated for the slurry flowing in the internal tube with ice mass fractions ranging from 0 to 30% and with flow velocities between 0.3 and 1.9 m s{sup -1}. For some flow velocities, the results showed that an increase in the ice fractions caused a change in the slurry flow structure influencing the evolution of the pressure drops and the heat transfer coefficients. Critical ice fraction values were determined corresponding to a change flow structure from laminar to turbulent motion revealed by the evolution of the friction factor. (author)

  1. Oscillating flow loss test results in Stirling engine heat exchangers (United States)

    Koester, G.; Howell, S.; Wood, G.; Miller, E.; Gedeon, D.


    The results are presented for a test program designed to generate a database of oscillating flow loss information that is applicable to Stirling engine heat exchangers. The tests were performed on heater/cooler tubes of various lengths and entrance/exit configurations, on stacked and sintered screen regenerators of various wire diameters and on Brunswick and Metex random fiber regenerators. The test results were performed over a range of oscillating flow parameters consistent with Stirling engine heat exchanger experience. The tests were performed on the Sunpower oscillating flow loss rig which is based on a variable stroke and variable frequency linear drive motor. In general, the results are presented by comparing the measured oscillating flow losses to the calculated flow losses. The calculated losses are based on the cycle integration of steady flow friction factors and entrance/exit loss coefficients.

  2. Highly durable direct hydrazine hydrate anion exchange membrane fuel cell (United States)

    Sakamoto, Tomokazu; Serov, Alexey; Masuda, Teruyuki; Kamakura, Masaki; Yoshimoto, Koji; Omata, Takuya; Kishi, Hirofumi; Yamaguchi, Susumu; Hori, Akihiro; Horiuchi, Yousuke; Terada, Tomoaki; Artyushkova, Kateryna; Atanassov, Plamen; Tanaka, Hirohisa


    The factors influenced on degradation of direct hydrazine hydrate fuel cells (DHFCs) under operation conditions are analyzed by in situ soft X-ray radiography. A durability of DHFCs is significantly improved by multi-step reaction DHFCs (MSR-DHFCs) approach designed to decrease the crossover of liquid fuel. An open circuit voltage (OCV) as well as cell voltage at 5 mA cm-2 of MSR-DHFC construct with commercial anion exchange membrane (AEM) maintained for over of 3500 h at 60 °C. Furthermore, the commercial proton exchange membrane (PEM) is integrated into AEM of MSR-DHFCs resulting in stable power output of MSR-DHFCs for over than 2800 h at 80 °C.

  3. Exchange fluctuation theorem for correlated quantum systems. (United States)

    Jevtic, Sania; Rudolph, Terry; Jennings, David; Hirono, Yuji; Nakayama, Shojun; Murao, Mio


    We extend the exchange fluctuation theorem for energy exchange between thermal quantum systems beyond the assumption of molecular chaos, and describe the nonequilibrium exchange dynamics of correlated quantum states. The relation quantifies how the tendency for systems to equilibrate is modified in high-correlation environments. In addition, a more abstract approach leads us to a "correlation fluctuation theorem". Our results elucidate the role of measurement disturbance for such scenarios. We show a simple application by finding a semiclassical maximum work theorem in the presence of correlations. We also present a toy example of qubit-qudit heat exchange, and find that non-classical behaviour such as deterministic energy transfer and anomalous heat flow are reflected in our exchange fluctuation theorem.

  4. Pseudo exchange bias due to rotational anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Ehrmann, A., E-mail: [Faculty of Engineering and Mathematics, Bielefeld University of Applied Sciences, 33619 Bielefeld (Germany); Komraus, S.; Blachowicz, T.; Domino, K. [Institute of Physics – Center for Science and Education, Silesian University of Technology, 44-100 Gliwice (Poland); Nees, M.K.; Jakobs, P.J.; Leiste, H. [Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen (Germany); Mathes, M.; Schaarschmidt, M. [ACCESS e. V., 57072 Aachen (Germany)


    Ferromagnetic nanostructure arrays with particle dimensions between 160 nm and 400 nm were created by electron-beam lithography. The permalloy structures consist of rectangular-shaped walls around a square open space. While measuring their magnetic properties using the Magneto-Optical Kerr Effect (MOKE), in some angular regions an exchange bias (EB) seemed to appear. This paper gives an overview of possible reasons for this “pseudo exchange bias” and shows experimentally and by means of micromagnetic simulations that this effect can be attributed to unintentionally measuring minor loops. - Highlights: • Pseudo exchange bias can be found in square Py nanorings of different dimensions. • Pseudo exchange bias stems from unintentionally measuring minor loops. • New approach in explaining “real” exchange bias effect in coupled FM/AFM systems. • Theoretical base to explain other measurements of a rotational anisotropy.

  5. Fertility as a process of social exchange

    Directory of Open Access Journals (Sweden)

    Patrick Heady


    Full Text Available By marrying and raising children, parents participate in a system of gift-exchange in which the gifts in question are human lives, and the parties to the exchange are the kinship groups recognised in the society concerned. Fertility reflects the attitudes of prospective parents to their place in the existing system of reproductive exchange, and the relationships of cooperation and authority which it implies - as well as their confidence in the system's continuing viability. It is shown that this view is compatible with earlier ideas about self-regulating population systems - and that changing economic circumstances are an important source of discrepancy between existing exchange systems and the attitudes and expectations of prospective parents. The discussion is developed with reference to data on European societies, including a case-study from the Alps, and concludes with an assessment of the relevance of the anthropological theory of gift exchange to contemporary fertility patterns in Europe and beyond.

  6. Minimax Decision for the Reliability of Aircraft Fleet with and Without Information Exchange


    Tretjakovs, S; Paramonovs, J


    The scientific article addresses the dependence of aircraft fleet safety on the human factor. The article demonstrates the significance of information exchange concerning the open fatigue cracks, which is necessary to bring a new type of aircraft into operation. The article provides numerical examples obtained by means of the Monte Carlo method and considers the dependences of failure probability on various factors.

  7. Perspectives of advanced thermal management in solar thermochemical syngas production using a counter-flow solid-solid heat exchanger (United States)

    Falter, Christoph; Sizmann, Andreas; Pitz-Paal, Robert


    A modular reactor model is presented for the description of solar thermochemical syngas production involving counter-flow heat exchangers that recuperate heat from the solid phase. The development of the model is described including heat diffusion within the reactive material as it travels through the heat exchanger, which was previously identified to be a possibly limiting factor in heat exchanger design. Heat transfer within the reactive medium is described by conduction and radiation, where the former is modeled with the three-resistor model and the latter with the Rosseland diffusion approximation. The applicability of the model is shown by the analysis of heat exchanger efficiency for different material thicknesses and porosities in a system with 8 chambers and oxidation and reduction temperatures of 1000 K and 1800 K, respectively. Heat exchanger efficiency is found to rise strongly for a reduction of material thickness, as the element mass is reduced and a larger part of the elements takes part in the heat exchange process. An increase of porosity enhances radiation heat exchange but deteriorates conduction. The overall heat exchange in the material is improved for high temperatures in the heat exchanger, as radiation dominates the energy transfer. The model is shown to be a valuable tool for the development and analysis of solar thermochemical reactor concepts involving heat exchange from the solid phase.

  8. Analysis of Exchange Interaction and Electron Delocalization as Intramolecular Determinants of Intermolecular Electron-Transfer Kinetics. (United States)

    Bominaar, E. L.; Achim, C.; Borshch, S. A.; Girerd, J.-J.; Münck, E.


    During the past decades, spectroscopic characterization of exchange interactions and electron delocalization has developed into a powerful tool for the recognition of metal clusters in metalloproteins. By contrast, the biological relevance of these interactions has received little attention thus far. This paper presents a theoretical study in which this problem is addressed. The rate constant for intermolecular electron-transfer reactions which are essential in many biological processes is investigated. An expression is derived for the dependence of the rate constant for self-exchange on the delocalization degree of the mixed-valence species. This result allows us to rationalize published kinetic data. In the simplest case of electron transfer from an exchange-coupled binuclear mixed-valence donor to a diamagnetic acceptor, the rate constant is evaluated, taking into account spin factors and exchange energies in the initial and final state. The theoretical analysis indicates that intramolecular spin-dependent electron delocalization (double exchange) and Heisenberg-Dirac-van Vleck (HDvV) exchange have an important impact on the rate constant for intermolecular electron transfer. This correlation reveals a novel relationship between magnetochemistry and electrochemistry. Contributions to the electron transfer from the ground and excited states of the exchange-coupled dimer have been evaluated. For clusters in which these states have different degrees of delocalization, the excited-state contributions to electron transfer may become dominant at potentials which are less reductive than the potential at which the rate constant for the transfer from the ground state is maximum. The rate constant shows a steep dependence on HDvV exchange, which suggests that an exchange-coupled cluster can act as a molecular switch for exchange-controlled electron gating. The relevance of this result is discussed in the context of substrate specificity of electron-transfer reactions in


    Directory of Open Access Journals (Sweden)

    BAKO Elena Dana


    Full Text Available This paper continues the series of researches about the paradoxes of modern stock exchange markets and their impact on the real economy, addressing this time the most important technical anomalies but also fundamental anomalies, which can be observed on the financial markets. As we mentioned in several previous articles, the paradoxes of stock exchanges are related to potential contradictions that arise in relation to a generally accepted truth. A lot of researches in the field of stock market investment focused on finding the answer to the question whether historical prices can be used to predict future prices for listed securities. Complex forecasting methods were created to clarify this aspect. Thus, technical analysis is a method of forecasting the price movements and trends of the market in the future, by studying the market graphs (including here both, the price of the listed instruments and the volume of transactions. The fundamental anomalies refer to the anomalies in trading financial instruments, and to the elements of fundamental analysis. The basic principle of fundamental analysis refers to the fact that the market price of any financial instrument is the result of supply and demand for that instrument. Both the supply and demand that finally determine the price of a financial instrument, are under the influence of various factors. Market’s analysts monitor various economic indicators and examine the market reports, to detect changes that may occur in the economy. The fundamental analysis attempts to predict prices and the overall market development by analyzing some economic indicators, political or social factors which are likely to influence the stock exchange prices. Both technical and fundamental anomalies have a major impact on price formation for financial instruments which are traded on stock exchanges, and are able to offer to warned investors higher earnings.

  10. 40 CFR 63.654 - Heat exchange systems. (United States)


    ... any one of the criteria in paragraphs (b)(1) through (2) of this section. (1) All heat exchangers that... any heat exchangers that are in organic HAP service as defined in this subpart). (c) The owner or... each heat exchanger exit line for each heat exchanger or group of heat exchangers in organic HAP...

  11. 40 CFR 63.1409 - Heat exchange system provisions. (United States)


    ... locations where the cooling water enters and exits each heat exchanger or any combination of heat exchangers.... (iii) For samples taken at the entrance and exit of each heat exchanger or any combination of heat exchangers, the entrance is the point at which the cooling water enters the individual heat exchanger or...

  12. 17 CFR 229.802 - Exchange Act industry guides. (United States)


    ... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Exchange Act industry guides. 229.802 Section 229.802 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION STANDARD... AND CONSERVATION ACT OF 1975-REGULATION S-K List of Industry Guides § 229.802 Exchange Act industry...

  13. The European-American exchange. (United States)

    Guerra, F


    The European-American exchange of infectious diseases was responsible for the demographic havoc of the native population in the New World after 1492. Prior to this date medical writers describe the presence in Spain of viral diseases like influenza, parotitis, smallpox, measles, poliomyelitis, and rabies; there were also rickettsiasis, diphtheria, salmonellosis, plague, tubercolosis, leprosy, malaria, scabies and tinea. In America, before European arrivals, there were no records of human viral diseases, though there were records of rickettsiasis, treponematosis--pinta, yaws and syphilis--leihsmaniasis, amibiasis and perhaps leprosy. With the discovery of America in 1492, Columbus's sailors were contaminated by yaws and spread this disease into Europe. In 1493 influenza, as a zoonosis, was introduced into Santo Domingo and was responsible for the annihilation of the natives of the Antilles in less than a quarter of a century; in 1518 smallpox was also introduced in Santo Domingo and then to the American continent by negro slaves: by the same means measles were introduced in 1531. The previous existence or introduction of other infectious diseases in America is also discussed.

  14. Therapeutic plasma exchange in Casablanca. (United States)

    Tazi, I; Merimi, F; Majd, A; Benchemsi, N


    Therapeutic plasma exchange (TPE) is an extracorporeal blood purification method for the treatment of diseases in which pathological proteins have to be eliminated. In the aim to demonstrate our single center activity, we analyzed our data since 2 years. Between years 2002 and 2005, 104 TPE procedures were performed on 42 patients. Median age and male/female ratio were 32 (range, 17-56) and 24/18, respectively. Departments those referred the majority of the TPE were neurology (n=32), nephrology (n=5) and intensive care unit (n=5). The most common indications were: polyradiculoneuropathies (53%), myasthenia gravis (17%) and Guillain-Barré syndrome (12%). The median TPE procedure per patient was 2.3 (range, 1-10). In the majority of patients, vascular access was provided by puncture of two large, durable peripheral antecubital veins. The procedures were performed with the "Haemonetic Ultralight" discontinuous flow cell separator devices. Citrate solution was used as an anticoagulant in all cases. The substitution fluids most often used in our unit are Albumin 20% solution (92 times), Albumin 4% (10 times) and fresh frozen plasma (twice). Seventy five percent of the patients showed improvement, 7% remained the same and 18% worsened. Thirteen adverse reactions were recorded. The creation of a national registry by the local society is a vital move to improve TPE practice in our country.

  15. The interplanetary exchange of photosynthesis. (United States)

    Cockell, Charles S


    Panspermia, the transfer of organisms from one planet to another, either through interplanetary or interstellar space, remains speculation. However, its potential can be experimentally tested. Conceptually, it is island biogeography on an interplanetary or interstellar scale. Of special interest is the possibility of the transfer of oxygenic photosynthesis between one planet and another, as it can initiate large scale biospheric productivity. Photosynthetic organisms, which must live near the surface of rocks, can be shown experimentally to be subject to destruction during atmospheric transit. Many of them grow as vegetative cells, which are shown experimentally to be susceptible to destruction by shock during impact ejection, although the effectiveness of this dispersal filter can be shown to be mitigated by the characteristics of the cells and their local environment. Collectively these, and other, experiments reveal the particular barriers to the cross-inoculation of photosynthesis. If oxygen biosignatures are eventually found in the atmospheres of extrasolar planets, understanding the potential for the interplanetary exchange of photosynthesis will aid in their interpretation.

  16. Update of CERN exchange network

    CERN Multimedia


    An update of the CERN exchange network will be done next April. Disturbances or even interruptions of telephony services may occur from 4th to 24th April during evenings from 18:30 to 00:00 but will not exceed more than 4 consecutive hours (see tentative planning below). In addition, the voice messaging system will be shut down on March, 26th April from 18:00 to 00:00. Calls supposed to be routed to the voice messaging system will not be possible during the shutdown. CERN divisions are invited to avoid any change requests (set-ups, move or removals) of telephones and fax machines from 4th to 25th April. Everything will be done to minimize potential inconveniences which may occur during this update. There will be no loss of telephone functionalities. CERN GSM portable phones won't be affected by this change. Should you need more details, please send us your questions by email to Date Change type Affected areas March 26 Update of the voice messaging system All CERN sites April...

  17. Update of CERN exchange network

    CERN Multimedia


    An update of the CERN exchange network will be done next April. Disturbances or even interruptions of telephony services may occur from 4th to 24th April during evenings from 18:30 to 00:00 but will not exceed more than 4 consecutive hours (see tentative planning below). In addition, the voice messaging system will be shut down on March, 26th April from 18:00 to 00:00. Calls supposed to be routed to the voice messaging system will not be possible during the shutdown. CERN divisions are invited to avoid any change requests (set-ups, move or removals) of telephones and fax machines from 4th to 25th April. Everything will be done to minimize potential inconveniences which may occur during this update. There will be no loss of telephone functionalities. CERN GSM portable phones won't be affected by this change. Should you need more details, please send us your questions by email to Date Change type Affected areas April 8 Update of switch in LHC 7 LHC 7 Point April 9 Update of...

  18. Update of CERN exchange network

    CERN Multimedia


    An update of the CERN exchange network will be done next April. Disturbances or even interruptions of telephony services may occur from 4th to 24th April during evenings from 18:30 to 00:00 but will not exceed more than 4 consecutive hours (see tentative planning below). In addition, the voice messaging system will be shut down on March, 26th April from 18:00 to 00:00. Calls supposed to be routed to the voice messaging system will not be possible during the shutdown. CERN divisions are invited to avoid any change requests (set-ups, move or removals) of telephones and fax machines from 4th to 25th April. Everything will be done to minimize potential inconveniences which may occur during this update. There will be no loss of telephone functionalities. CERN GSM portable phones won't be affected by this change. Should you need more details, please send us your questions by email to DateChange typeAffected areas March 26Update of the voice messaging systemAll CERN sites April 4Updat...

  19. Update of CERN exchange network

    CERN Multimedia


    An update of the CERN exchange network will be done next April. Disturbances or even interruptions of telephony services may occur from 4th to 24th April during evenings from 18:30 to 00:00 but will not exceed more than 4 consecutive hours (see tentative planning below). CERN divisions are invited to avoid any change requests (set-ups, move or removals) of telephones and fax machines from 4th to 25th April. Everything will be done to minimize potential inconveniences which may occur during this update. There will be no loss of telephone functionalities. CERN GSM portable phones won't be affected by this change. Should you need more details, please send us your questions by email to DateChange typeAffected areas April 11 Update of switch in LHC 4 LHC 4 Point April 14 Update of switch in LHC 5 LHC 5 Point April 15 Update of switches in LHC 3 and LHC 2 Points LHC 3 and LHC 2 April 22 Update of switch N4 Meyrin Ouest April 23 Update of switch  N6 Prévessin Site Ap...

  20. Plant uptake of radionuclides and rhizosphere factors

    Energy Technology Data Exchange (ETDEWEB)

    Arie, Tsutomu; Gouthu, S.; Ambe, Shizuko; Yamaguchi, Isamu [Institute of Physical and Chemical Research, Wako, Saitama (Japan); Hirata, Hiroaki


    Influence of soil factors such as nuclide availability, pH, organic carbon, cation exchange capacity (CEC), exchangeable cations (Ca{sup 2+}, Mg{sup 2+}, and K{sup +}), phosphate absorption coefficient (PAC), physical composition of soil (coarse sand, fine sand, silt, and clay), soil texture, and rhizosphere microbes on uptake of radionuclides by plants are studied. (author)