Littérature scientifique sur le sujet « Onde calcio »
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Articles de revues sur le sujet "Onde calcio"
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Freitas, Nélio Martins, Angela Maria Correa Mouzinho Santos et Lucy Rose de Maria Oliveira Moreira. « AVALIAÇÃO FITOQUÍMICA E DETERMINAÇÃO DE MINERAIS EM AMOSTRAS de Hibiscus sabdariffa L (vinagreira) ». Cadernos de Pesquisa 20, no 3 (21 décembre 2013) : 65. http://dx.doi.org/10.18764/2178-2229.v20n3p65-72.
Texte intégralRésumé :
O presente trabalho teve como objetivo determinar por espectroscopia de emissão óptica com plasma indutivamente acoplado (ICP OES) o teor dos minerais cobalto, cobre, ferro, fósforo, cálcio, magnésio,manganês, níquel, potássio e zinco, presentes nas folhas e no caule do Hibiscus sabdariffa L (vinagreira).Fez-se a triagem fitoquímica para verificar os compostos fitoquímicos como saponinas, taninos, fenóis, terpenos, esteróides, alcalóides, resinas, e flavonóides) da vinagreira coletada do município de São José de Ribamar-MA, onde os agricultores plantam o H. sabdariffa L) e comercializam para a maioria das feiras dessa região. Para os testes fitoquímicos realizados no caule e nas folhas da planta observaram-se saponinase esteróides moderamente positivo, taninos tanto condensado como hidrolisado fraco positivamente. As resinas foram encontradas moderadamente no caule e ausente na folha do H. sabdariffa L. Para os teste de flavonóides obteve reação forte para o caule e moderada para a folha. Observou-se a ausência de fenóis, terpenos e alcalóides. Em relação ao teor de metais presente no caule e na folha do H. sabdariffa L (vinagreira) verificaram-se respectivamente, uma quantidade significativa de ferro (11,91 e 30,04 mg/l) e cálcio (6,08 e 7,09 mg/l); para os demais minerais, o teor foi menor: magnésio (0,31 mg/l), potássio (0,36 e 0,72 mg/l) manganês (0,14 e 0,02 mg/l) e fósforo somente nas folhas (0,62 mg/l).Palavras-chave: Hibiscus sabdariffa L. Minerais. Espectroscopia. PHYTOCHEMISTRY EVALUATION AND DETERMINATION OF MINERAL SIN SAMPLES Hibiscus Sabdariffa L (vinegar)Abstract: This study aimed to determine by optical emission spectroscopy with inductively coupled plasma (ICP OES), the mineral content of cobalt, copper, iron, phosphorus, calcium, magnesium, manganese, nickel,potassium and zinc, present in the leaves and the stem of Hibiscus sabdariffa L (vinagreira). Became the phytochemical screening to check phytochemicals like saponins, tannins, phenols, terpenes, steroids, alkaloids, resins, and flavonoids) of vinegar collected in São José de Ribamar-MA, where farmers plant H. sabdariffa L ), and trade fairs for most of this region. For the tests performed phytochemicals in stems and leaves of the plant was observed saponins and steroids moderately positive, both condensed tannins hydrolyzateas weak positive. The resins were found moderately in stems and absent in leaf H. sabdariffa L. For the test flavonoids obtained strong reaction to stem and leaf to moderate. We observed the absence of phenols, terpenes and alkaloids. WRegarding the metal content present in the stem and leaf H. sabdariffa L (vinegar) respectively, a significant amount of iron (11,91 and 30,04 mg /l), calcium (6,08 and 7,09 mg/l) for the remaining minerals content was lower: Magnesium (0,31 mg/l), potassium (0,36 and 0,72 mg /l) Mn (0,14 and 0,02 mg/ l) and only on phosphor sheets (0,62 mg/l).Keywords: Hibiscus sabdariffa L. Mmineral. Spectroscopy. EVALUACIÓN FITOQUÍMICA Y DETERMINACIÓN DE MINERALES EN MUESTRA SEN MUESTRAS Hibiscus SabdariffaL (vinagre)Resumen: Este estudio tuvo como objetivo determinar por espectroscopia de emisión óptica con plasma acoplado inductivamente (ICP OES), la concentración de minerales de cobalto, cobre, hierro, fósforo, calcio,magnesio, manganeso, níquel, potasio y zinc, presentes en las hojas y el tallo de Hibiscus sabdariffa L (vinagrera). Se realizaron los ensayos generales para comprobar la presencia de fitoquímicos como saponinas,taninos, fenoles, terpenos, esteroides, alcaloides, resinas y flavonoides) en la vinagrera recogida en São José de Ribamar-MA, donde los agricultores siembran H. sabdariffa L, y la comercializan en las ferias de la mayor parte de esta región. En las pruebas realizadas para la detección de fitoquímicos en los tallos y hojas de la planta se observó saponinas y esteroides moderadamente positivos, taninos tanto condensados como hidrolizados dando positivo débil. Las resinas se encuentran moderadamente en los tallos y ausentes en las hojas de H. sabdariffa L. En los ensayos para flavonoides se obtuvo fuerte reacción en los tallos y moderada en las hojas. Se observó la ausencia de fenoles, terpenos y alcaloides. En cuanto al contenido de metales presentes en el tallo y en las hojas de H. sabdariffa L (vinagrera), respectivamente había una cantidad significativa de hierro (11,91 y 30,04 mg / l), y calcio (6,08 y 7 09 mg / l) para el restante de los minerales el contenido fue menor: de magnesio (0,31 mg / l), potasio (0,36 y 0,72 mg / l) Mn (0,14 y 0,02 mg / l ) y fósforo sólo en las hojas (0,62 mg/l).Palabras clave: Hibiscus sabdariffa L. Minerals. Espectroscopia.
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Hernández-Somerson, Mario Andrés. « Onda sinusoidal en el electrocardiograma ». Acta Médica Colombiana 41, no 1 (23 juin 2016) : 74. http://dx.doi.org/10.36104/amc.2016.572.
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Mujer de 58 años, con cuadro de una semana de evolución consistente en astenia progresiva, disnea con esfuerzos medianos y en últimas 48 horas somnolencia marcada. No refiere antecedentes de importancia.
A su ingreso con Tensión arterial en 90/60, frecuencia cardíaca: 50 por minuto, frecuencia respiratoria 14 por minuto y afebril. Se observa con signos de deshidratación grado II y estuporosa. Se toma glucometría en 95 mg/dL y electrocardiograma (figura 1) con evidencia ausencia de onda P con R-R regular y ensanchamiento del complejo QRS (130 mseg), con intervalo QT corregido prolongado (460 mseg) y trastorno inespecífico de la repolarización. Se inicia manejo hídrico, oxigenoterapia, monitoreo electrocardiográfico y se toman paraclínicos. Se realiza electrocardiograma de control a los 10 minutos que muestra la presencia de una onda sinusoidal (figura 2).
Ante la sospecha de hiperpotasemia, se inicia gluconato de calcio intravenoso al 10%, 10 cc cada 10 minutos hasta reversión de la onda sinusoidal (figura 3) , en total requirió 40 cc. Se reciben niveles de potasio en 8.6 meq/L, creatinina en 10 mg/dl y nitrógeno ureico en 110 mg/dL. Se complementa manejo farmacológico para hiperpotasemia y se interconsulta al servicio de nefrología para inicio de terapia de reemplazo renal urgente.
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Yoplac, Ives Julian, Katerin Goñas, Wilmer Bernal, Héctor V. Vásquez et Jorge L. Maicelo. « Caracterización química y digestibilidad in vitro de semillas y subproductos agroindustriales amazónicos con potencial para alimentación animal ». Revista de Investigaciones Veterinarias del Perú 32, no 3 (23 juin 2021) : e18765. http://dx.doi.org/10.15381/rivep.v32i3.18765.
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Se determinaron las características químicas y digestibilidad in vitro de once insumos, divididos en tres grupos: semillas (sacha inchi [(Plukenetia volubilis], higuerilla [Ricinus communis] y chía [Salvia hispanica]), subproductos derivados del arroz (nielen, cascarilla y polvillo) y residuos agroindustriales de plantas y frutas tropicales (bagazo de caña de azúcar, pulpa de café, casco externo y mucílago de cacao [Theobroma cacao)], pulpa de naranja [Citrus sinensis] y vaina de taya [Caesalpinia spinosa]) con potencial en la alimentación animal. Las muestras fueron recolectadas en la región Amazonas, Perú. Se determinó su composición proximal, contenido de fibra cruda (FC), fibra detergente neutra (FDN), fibra detergente ácida (FDA), calcio y fósforo, así como la digestibilidad in vitro y energía bruta (EB). Las semillas oleaginosas destacaron por su alto contenido de aceites, alto valor energético e importante fuente de calcio y fósforo; el sacha inchi presentó alto contenido proteico de 28.75 ± 0.29%. Los subproductos del arroz mostraron ser importantes fuentes de carbohidratos, con alta digestibilidad a excepción de la cascarilla. Este último, al igual que los residuos de caña de azúcar y cacao, mostró un alto contenido de FC, FDA y FDN. Dentro de los demás residuos agroindustriales, la pulpa de café presentó mayor contenido proteico con 9.7%; los residuos de naranja y taya mayores valores de calcio (entre 0.5 y 0.7%), fósforo (entre 0.3 y 0.5%) y alta digestibilidad (entre 93 y 95%). Por tanto, los insumos evaluados, por su composición química, bajo costo y biodisponibilidad, muestran potencial para alimentación animal.
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Dornelas, Henrique Lopes. « Modernidade, cidade e ambivalência ». Confluências | Revista Interdisciplinar de Sociologia e Direito 2, no 1 (13 décembre 2003) : 11. http://dx.doi.org/10.22409/conflu2i1.p20050.
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O espírito da Modernidade - estreitamente ligado ao conceito de progresso - está calcado no estabelecimento da ordem em detrimento do caos, sendo erigida uma ordem artificial na qual a tarefa seria a de excluir tudo que seja ambíguo. Nessa perspectiva, o presente texto vem tentar discutir as relações entre Modernidade - enquanto produção da ordem -, ambivalência - enquanto refugo da prática moderna- e a cidade - enquanto palco onde irão se desenvolver tais contradições.
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Márquez Prieto, Antonio. « Entre algoritmos : género humano y género artificial. » E-REVISTA INTERNACIONAL DE LA PROTECCION SOCIAL 7, no 1 (2022) : 30–51. http://dx.doi.org/10.12795/e-rips.2022.i01.03.
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La inteligencia artificial, que lleva ya décadas de desarrollo, supone cada vez más una realidad presente en las relaciones laborales, de forma sectorizada, pero evidenciándose al mismo tiempo en toda la realidad económica y social. Por ello aquí se aborda como fenómeno universal ante el que se intentan ofrecer medidas legales de regulación, las cuales, en la medida en que responden al binomio conducta-norma, resultan inadecuadas puesto que el desarrollo de la inteligencia artificial requiere un enfoque en el que entre en juego, como tercer elemento, la propia cultura humana de valores subyacentes. Desde este punto de vista se pretende llamar la atención sobre el hecho de que la inteligencia artificial constituye un fenómeno de enorme calado filosófico y, al mismo tiempo, supone una de las mejores oportunidades para el intento global de comprensión de lo que significa ser humano.
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Pereira, Sueli Menezes, et Oséias Santos de Oliveira. « Constituição e funcionamento do Conselho Municipal de Educação frente ao processo de democratização da gestão : um estudo dos municípios de Santa Maria e Santa Rosa/RS ». Ensaio : Avaliação e Políticas Públicas em Educação 19, no 72 (septembre 2011) : 651–78. http://dx.doi.org/10.1590/s0104-40362011000400010.
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O artigo parte de um estudo qualitativo, calcado em uma pesquisa bibliográfica e documental com objetivo de discutir aspectos referentes à constituição e funcionamento do Conselho Municipal de Educação (CME), como órgão colegiado que se reveste de importante significado para a democratização da gestão educacional. A ênfase da análise recai sobre os CMEs dos municípios gaúchos de Santa Maria e Santa Rosa que, dadas as suas diferenças e peculiaridades, projetam tais órgãos ainda atrelados a uma estrutura formal intermediária. O desafio dos CMEs é funcionar de forma autônoma frente as suas inúmeras atribuições de modo a dar respostas que sinalizem à criação de novos caminhos à educação pública municipal. Atuar de forma diferenciada em um cenário onde a maioria dos conselhos se alinham a uma lógica formal e burocratizada e onde ainda são vistos como órgão de assessoramento do poder governamental é, sem dúvida, uma meta a ser perseguida na busca da democratização deste espaço público.
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Cestaro Remundini, Elerson, et Vera Helena Gomes Wielewicki. « Por uma educação multimodal e pluralista ». Letras & ; Letras 35, especial (23 octobre 2019) : 281–314. http://dx.doi.org/10.14393/ll63-v35nesp2019-14.
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Vivemos numa sociedade grafocêntrica, onde o ensino é calcado na leitura. Isso acaba por privar alunos disléxicos do conhecimento, já que eles enfrentam dificuldades para ler. Este trabalho propõe a utilização de imagens como complemento no ensino de inglês para disléxicos com foco na oralidade. Serão expostos exemplos de atividades voltadas para o ensino do verb to be aplicadas junto a alunos com dislexia, com base na noção de multiletramentos (COPE; KALANTZIS, 2009), além dos resultados alcançados por eles nos instrumentos de avaliação. Tais resultados demonstraram que uma pedagogia dos multiletramentos, que lance luz para além da escrita, é promissora para alunos cuja habilidade da leitura é prejudicada, mas também para os que leem fluentemente.
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Paris, Eleonora, Ziyu Wu, Annibale Mottana et Augustο Marcelli. « Calcium environment in omphacitic pyroxenes : XANES experimental data versus one-electron multiple scattering calculations ». European Journal of Mineralogy 7, no 5 (5 octobre 1995) : 1065–70. http://dx.doi.org/10.1127/ejm/7/5/1065.
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Biyoune, Mohamed Ghali, Brahim Bouargane, Hicham Bari, Abdelkhalek Marrouche, Raddoine Bellajrou, Ali Atbir, Laarbi Boukbir et Said Mançour Billah. « Water quality depends on remineralization’s method in the desalination plant ». Mediterranean Journal of Chemistry 10, no 2 (14 février 2020) : 162–70. http://dx.doi.org/10.13171/mjc10202002141228mgb.
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Desalination of seawater is an alternative solution in arid zones to provide potable water. In south Morocco, the National Office of Electricity and Water (ONEE) has built many desalination factories. However, the osmosis water (permeate) is unbalanced and has a corrosive character. Therefore, a post-treatment of remineralization is necessary to return to water its calcio-carbonic equilibrium and to protect the distribution pipelines from corrosion degradation. Following the performance on limestone bed remineralization in Daoura plant in comparison with other methods, this article evaluates this technique, by checking the effect of parameters on water quality on the laboratory scale using a calcite bed pilot. We tested E.B.C.T (Empty Bed Contact Time), the upward speed, the bed length, the effect of water debit and the residence time on the treated water quality. Monitoring these parameters on the laboratory scale is indeed essential for optimal remineralization process. With the results of this study as well as economic consideration, it is possible to optimize the choice of the conditions needed for remineralization operation through limestone bed to minimize its costs with sizing and extrapolating to the industrial scale.
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Tomm, Davi Alexandre. « Mimetização e linguagem em Vidas Secas : uma abordagem benjaminiana ». Cadernos Benjaminianos 1, no 8 (27 mai 2016) : 34. http://dx.doi.org/10.17851/2179-8478.1.8.34-48.
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O presente trabalho fará uma análise do livro de Graciliano Ramos, Vidas Secas, de 1938, através da teoria de Walter Benjamin sobre a faculdade mimética e sobre a linguagem. Pretende-se mostrar que os personagens do livro de Graciliano, que são caracterizados por não possuírem uma linguagem articulada mais desenvolvida, possuem a faculdade mimética do homem primitivo, pois vivem em um mundo ainda calcado pelas relações mágicas, onde a necessidade de saber ler a natureza nas suas semelhanças e relações é tão importante quanto o bem falar. Por fim, será evidenciado que é papel do narrador utilizar a linguagem articulada, já de posse da função semiótica, para dar voz aos personagens, mimetizando, através de seu estilo, a vida e os pensamentos deles.
Thèses sur le sujet "Onde calcio"
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FORCAIA, GRETA. « Multifunctional Liposomes modulate Purinergic Receptor-induced Calcium Wave in Cerebral Microvascular Endothelial Cells and Astrocytes ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2020. http://hdl.handle.net/10281/261943.
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I nostri precedenti studi dimostrano che liposomi multifunzionalizzati con il monomero dell’ApoE e con acido fosfatidico (mApoE-PA-LIP) riducono l’accumulo di Aβ nel cervello migliorando il declino cognitivo in modelli murini di malattia di Alzheimer (AD) (Balducci et al., 2014). In riferimento ai nostri precedenti risultati, abbiamo studiato l’interazione di liposomi funzionalizzati con un peptide derivante dall’ApoE (mApoE) e acido fosfatidico (PA), con le cellule che costituiscono l’unità neurovascolare. In particolar modo, abbiamo valutato la loro attività in cellule di microcircolo cerebrale umano (hCMEC/D3), utilizzate come modello in vitro di barriera ematoencefalica, e in astrociti in coltura (iAstro-WT). Grazie a misurazioni effettuate con la tecnica del calcium imaging abbiamo studiato le dinamiche di calcio intracellulare generate dall’attivazione dei recettori purinergici. I nostri risultati mostrano che l’interazione dei mApoE-PA-LIP con le hCMEC/D3 e gli astrociti inducono attivamente una modulazione della durata delle onde di calcio indotte dall’attivazione dei recettori purinergici stimolati da ATP. In particolare, possiamo confermare che il pre-trattamento con i mApoE-PA-LIP induce un aumento significativo della durata della risposta indotta dall’ATP che non si verifica nelle cellule controllo. Dopo il pre-trattamento con mApoE-PA_LIP, anche l’area sotto la curva (AUC) risulta essere maggiore rispetto alle cellule non pre-trattate sia nelle hCMEC che negli iAstro-WT.
Possiamo inoltre affermare che il pre-trattamento con i mApoE-PA-LIP in assenza di calcio extracellulare, aumenta in modo significativo sia i valori di durata di risposta al calcio allo stimolo di ATP sia quelli di AUC paragonati ai controlli. In aggiunta, abbiamo trovato che quando la pompa del calcio del reticolo sarcoplasmatico (SERCA) è inattiva, perché selettivamente bloccata dall’acido ciclopiazonico, in presenza o assenza di calcio extracellulare, l’ATP non riesce a generare onde di calcio anche dopo pre-trattamento con i mApoE-PA-LIP.
In conclusione, considerando il ruolo neuroprottettivo dell’attivazione dei recettori purinergici (Weisman et al., 2012), possiamo affermare che i mApoE-PA-LIP modulano le dinamiche al calcio ATP indotte quando la SERCA è attiva. I nostri risultati potrebbero aggiungere dati interessanti utili a promuovere i mApoE-PA-LIP come innovativo strumento per il trattamento della malattia di Alzheimer.Our previous results show that multifunctional liposomes (mApoE-PA-LIP) reduce brain Aβ burden and ameliorate memory impairment in Alzheimer’s disease (AD) mouse models (Balducci et al., 2014). In light of these results, we assessed liposomes functionalized with ApoE-derived peptide (mApoE) and phosphatidic acid (PA) at neurovascular unit. In particular, we evaluated their activities on cultured human cerebral microvascular cells (hCMEC/D3), as an in vitro human blood brain barrier model, and on cultured astrocytes (iAstro-WT). By means of calcium imaging measurements, we aimed to study the intracellular calcium dynamics triggered by purinergic receptors activation. Our result show that the interaction of mApoE-PA-LIP with the hCMEC/D3 and astrocytes actively induced a modulation in the calcium waves duration of ATP evoked response. In particular, we find an increase of the duration of the ATP evoked calcium waves in presence of mApoE-PA-LIP in comparison to untreated cells. After the mApoE-PA-LIP pre-treatment also the area under the curve (AUC) is increased in comparison to controls both in hCMEC and iAstro-WT. Furthermore, we found that the pre-treatment with mApoE-PA-LIP in absence of extracellular calcium significantly increased ATP evoked calcium waves in comparison to controls. Also under this condition, the AUC increased in comparison to control. We also found that when the Sarco-Endoplasmic Reticulum Calcium ATPase (SERCA) was inactive, due to its specific blockage with cyclopiazonic acid, both in presence or in absence of extracellular calcium, ATP failed to activate calcium wave also after a pre-treatment with mApoE-PA-LIP both in hCMEC and iAstro-WT. In conclusion, mApoE-PA-LIP modulate calcium dynamics evoked by ATP when SERCA is active. In light of the protective role of the purinergic receptor activation (Weisman et al., 2012), our obtained results would provide an additional support to promote mApoE-PA-LIP as putative therapeutic tool for AD treatment.
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Aymer, de la Chevalerie Dominique. « Interaction onde de choc-couche limite modélisation et calcul ». Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37595581g.
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Hathouti, Abdelhadi. « Calcul des champs dans les fours micro-ondes ». Toulouse, INPT, 1994. http://www.theses.fr/1994INPT024H.
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La conception des fours micro-ondes industriels et domestiques fait encore appel a l'experience et a l'empirisme car les outils de modelisation ne sont pas encore suffisamment developpes. Ce travail tente d'apporter une reponse par une double modelisation bidimensionnelle ecrite par la methode des elements finis et qui cherche a simuler la repartition volumique. Le champ thermique est fonction du materiau par ses caracteristiques electriques et thermiques, par sa forme et sa position dans le four mais aussi du four lui meme et de son excitation. Ce travail aborde ces differents aspects et insiste plus particulierement sur l'influence de la position des sources de champ
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GABER, OUSSAMA. « Ondes de choc supersoniques et calcul formel ». Paris 6, 1999. http://www.theses.fr/1999PA066563.
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La determination par les methodes numeriques de l'evolution instationnaire ou stationnaire de l'onde de choc detachee qui se forme a l'avant d'un obstacle se deplacant a une vitesse supersonique ou hypersonique est couteuse en temps et demande de gros moyens de calculs surtout pour des resultats precis. Certains auteurs ont propose une autre approche dans laquelle le choc est donne par un developpement en serie de taylor. Nous proposons dans ce travail, de valider et etendre cette methode originale utilisant les approximants de pade et le calcul formel. Cette methode a trois principaux avantages : elle ne necessite aucun maillage, depend seulement de la forme de l'obstacle et est peu couteuse en temps. Une fois les coefficients de taylor calcules, on leur a appliques les approximants de pade. Le calculs de ces coefficients requiert la resolution d'un systeme lineaire qui devient vite imposant avec les ordres superieurs. Le calcul formel nous a permis de calculer les ordres superieures de la serie de taylor et donc de pade. Une comparaison avec des resultats numeriques de refernce pour des cas 2d et 3d ont confirmes dans une certaine limite la pertinence de la methode. La resolution du systeme lineaire pour le choc et le calcul formel nous ont permis une extension de la methode pour obtenir, avec un certain succes, la solution complete du champ fluide compris entre l'obstacle et le choc.
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Peyraut, François. « Calcul et visualisation de l'amortissement d'une onde harmonique dans un multicouche viscoelastique ». Paris 6, 1991. http://www.theses.fr/1991PA066609.
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Pour rendre indetectable les sous-marins aux sonars ennemis, on concoit des revetements anechoiques susceptibles de reduire l'echo de la coque. Ces revetements sont constitues de materiaux viscoelastiques au sein desquels les ondes s'amortissent par dissipation. Pour evaluer l'amortissement, on calcule l'energie dissipee par de tels revetements a l'aide de la thermodynamique des milieux continus. En modelisant le comportement viscoelastique par une convolution en temps au sens des distributions, on se place dans le cadre le plus general possible. La determination des ondes se propageant au sein de revetements multicouches viscoelastiques est realisee avec une methode de matrice de transfert. Lorsque l'epaisseur des couches constituant le revetement est faible devant la longueur d'onde, on couple cette methode avec l'utilisation de l'homogeneisation periodique. Deux methodes d'homogeneisation ont ete developpees. La premiere consiste a homogeneiser l'operateur de viscoelasticite harmonique. La deuxieme methode repose sur l'homogeneisation de l'equation du mouvement dans une multicouche. Pour interpreter les resultats, un logiciel de post-traitement graphique a ete developpe a partir des elements de la bibliotheque phigs (programmer's hierarchical interactive graphics system). Ce logiciel est destine a visualiser les isovaleurs d'une fonction dependant de trois parametres dans un ou plusieurs plans de coupe. L'accent a ete mis sur le developpement de fonctionnalites de manipulation d'objets tridimensionnels
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Escande, Béatrice. « Modélisation de l'interaction onde de choc/couche limite turbulente comparaison calcul-expérience ». Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb375974105.
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Mora, Frédéric. « Visibilité polygone à polygone : calcul, représentation, application ». Poitiers, 2006. http://www.theses.fr/2006POIT2292.
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Cette thèse aborde le problème du calcul et de la représentation de la visibilité mutuelle de polygones. Elle montre tout le potentiel et l'intérêt de cette information pour la résolution de problèmes difficiles en synthèse d'images et en propagation électromagnétique. Nous proposons un nouvel algorithme pour calculer la visibilité dans l'espace de Plücker, afin de minimiser les coûts en temps et mémoire vis-à-vis des précédentes approches. En synthèse d'images, nous utilisons l'information ainsi calculée pour proposer une nouvelle solution au calcul analytique des ombres douces en illumination directe. Cette solution concilie la qualité et la rapidité du rendu. En propagation électromagnétique, nous proposons l'optimisation sans perte d'un modèle basé rayons. Celle-ci permet d'effectuer des simulations dont la précision est optimale tout en s'appliquant à des environnements de tailles significativesThis thesis addresses the visibility computation between two polygons and its representation. We bring up the potential of this information to solve difficult problems in image synthesis and in electromagnetic waves propagation. We present a new algorithm for the visibility computation in the Plücker space. In comparison to previous methods, it reduces the time computation and the memory requirements. In image synthesis, we use the computed information to design a new solution for the analytic computation of soft shadows. This solution is both accurate and fast in comparison with stochastic approaches. In electromagnetic waves propagation, we present the first ray based model optimisation without path lost. This optimisation allows to perform accurate simulations on significant environments
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Dupont, Geneviève. « Modélisation des oscillations et des ondes de calcium intracellulaire ». Doctoral thesis, Universite Libre de Bruxelles, 1993. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212822.
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Bruyant, Jean Paul. « Calcul de la diffraction d'une onde plane par une paroi diélectrique à surface rainurée ». Bordeaux 1, 1985. http://www.theses.fr/1985BOR10627.
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Diffraction par un cylindre dielectrique de section arbitraire. Influence des effets de bord et calcul des performances de rubans dielectriques. Diffraction par un panneau dielectrique a surface rainuree
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KAHAN, MICHEL. « Approches stochastiques pour le calcul des ponts aux séismes ». Marne-la-vallée, ENPC, 1996. http://www.theses.fr/1996ENPC9609.
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Nous proposons quelques méthodes stochastiques pour le calcul des ponts aux séismes. Nous étudions l'effet de la variabilité spatiale des ondes sismiques sur la réponse linéaire des ouvrages d'art grâce à une méthode de spectre de réponse pour structures multi-supportées. Nous proposons une méthode simplifiée pour le calcul rapide de la sensibilité des ouvrages à de petites variations spatiales ainsi qu'un algorithme pour déterminer la sollicitation la plus défavorable. Pour tenir compte des capacités de ductilité, nous proposons une méthode de spectre de réponse non-linéaire. Elle s'appuie sur une linéarisation stochastique de la structure. La localisation des non-linéarités est mise à profit dans une synthèse modale adaptée. On obtient de bons résultats en termes de demande de ductilité et d'énergie dissipée par hystérésis dans les éléments non-linéaires. Enfin, nous évoquons une technique de calcul de fiabilité de structures non-linéaires sous sollicitations stochastiques.
Livres sur le sujet "Onde calcio"
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Keown, Tim. Skyline : One season, one team, one city. New York : Macmillan, 1994.
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Hays, Gayleen. Policewoman one : My twenty years on the LAPD. New York : Villard Books, 1992.
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California Energy Commission. Siting Office. Staff assessment and draft environmental impact statement, Calico Solar Project : Application for certification (08-AFC-13), San Bernardino County. Sacramento, Calif.] : California Energy Commission, 2010.
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Dempsey, Thomas Gregwer. True stories cops tell to one another. San Francisco, CA : T. Dempsey, 1998.
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Willis, Clare. Once bitten. New York : Kensington Pub., 2009.
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Hostage One. New York City, New York, USA : Random House, 1989.
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Epperson, Tom. The kind one. New York : Pocket Books, 2009.
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Tyler, Ben. One night stand. New York : Kensington Books, 2004.
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Deutsch, Rick. One best hike : Yosemite's Half Dome. 2e éd. Birmingham, AL : Wilderness Press, 2012.
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Doherty, Dave. There once was a place called P.O.P. [Bloomington, IN] : Xlibris, 2008.
Trouver le texte intégralChapitres de livres sur le sujet "Onde calcio"
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Tveito, Aslak, et Glenn T. Lines. « One-Dimensional Calcium Release ». Dans Lecture Notes in Computational Science and Engineering, 23–54. Cham : Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-30030-6_2.
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Gosling, Peter. « Lesson One ». Dans Easily into Super Calc® 4, 3–8. London : Macmillan Education UK, 1989. http://dx.doi.org/10.1007/978-1-349-10476-5_1.
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Pettegree, Andrew. « Chapter One : Calvin and Luther as Men of the Book ». Dans Calvin and the Book, 17–32. Göttingen : Vandenhoeck & Ruprecht, 2015. http://dx.doi.org/10.13109/9783666550881.17.
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Cates, Dennis M. « DECOMPOSITION OF A DEFINITE INTEGRAL INTO SEVERAL OTHERS. IMAGINARY DEFINITE INTEGRALS. GEOMETRIC REPRESENTATION OF REAL DEFINITE INTEGRALS. DECOMPOSITION OF THE FUNCTION UNDER THE $$\int $$ SIGN INTO TWO FACTORS IN WHICH ONE ALWAYS MAINTAINS THE SAME SIGN. » Dans Cauchy's Calcul Infinitésimal, 123–27. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-11036-9_23.
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Hirota, E., K. Kuchitsu, T. Steimle, J. Vogt et N. Vogt. « 66 CaHO Calcium(I) hydroxide ». Dans Molecules Containing No Carbon Atoms and Molecules Containing One or Two Carbon Atoms, 97. Berlin, Heidelberg : Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-540-70614-4_67.
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Hirota, E., K. Kuchitsu, T. Steimle, J. Vogt et N. Vogt. « 67 CaHS Calcium hydrogen sulfide ». Dans Molecules Containing No Carbon Atoms and Molecules Containing One or Two Carbon Atoms, 98. Berlin, Heidelberg : Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-540-70614-4_68.
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Hirota, E., K. Kuchitsu, T. Steimle, J. Vogt et N. Vogt. « 22 BCaH4 Tetrahydroborato(1-)-H,H',H''-calcium ». Dans Molecules Containing No Carbon Atoms and Molecules Containing One or Two Carbon Atoms, 52. Berlin, Heidelberg : Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-540-70614-4_23.
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Brownlee, C., N. F. H. Manison et R. Anning. « Calcium, polarity and osmoregulation inFucus embryos : one messenger, multiple messages ». Dans EBO Experimental Biology Online Annual 1998, 145–61. Berlin, Heidelberg : Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-642-60083-8_11.
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Aldenhoff, J. B. « Lithium and Calcium Antagonists : Do They Act on One Neuronal Function ? » Dans New Directions in Affective Disorders, 142–44. New York, NY : Springer New York, 1989. http://dx.doi.org/10.1007/978-1-4612-3524-8_32.
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Wilson, Helen, Diana Calcraft, Cai Neville, Susan Lanham-New et Louise R. Durrant. « Bone Health, Fragility and Fractures ». Dans Perspectives in Nursing Management and Care for Older Adults, 115–34. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63892-4_9.
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AbstractAchieving and maintaining skeletal health throughout the life trajectory is essential for the prevention of bone diseases such as rickets, osteomalacia and osteoporosis. Rickets and osteomalacia are usually a result of calcium and/or vitamin D deficiency, causing softening of bones and bone pain, and both conditions are treatable with calcium and vitamin D supplementation. Osteoporosis is a multifaceted disease mainly affecting older people, and its pathogenesis (and hence treatment) is more complex. Untreated osteoporosis results in fragility fractures causing morbidity and increased mortality.Nutrition is one of many factors that influence bone mass and risk of bone disease. Developing a nutritional sciences approach is a feasible option for improving bone health.The importance of adequate calcium and vitamin D in ensuring skeletal integrity throughout the life course has a sound evidence base. Poor vitamin D status in population groups of all ages is widespread across many countries (including affluent and non-affluent areas). Public health approaches are required to correct this given the fact that vitamin D is not just required for musculoskeletal health but also for other health outcomes.Dietary protein may be beneficial for bone due to its effect of increasing insulin-like growth-factor-1 (IGF-1). Recent meta-analyses show that dietary protein has a beneficial role to play in bone health at all ages.Other nutritional factors and nutrients (such as potassium, magnesium, vitamin K and acid-base balance) are also likely to have an important role in bone health, though the literature is less clear in terms of the association/relationship and more research is required.
Actes de conférences sur le sujet "Onde calcio"
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Zhang, Nan, Amy T. Kan et Mason B. Tomson. « Attchment/Release of Phosphonate to/from a CaCO3 Surface in Supersaturated Brines ». Dans SPE International Oilfield Scale Conference and Exhibition. SPE, 2014. http://dx.doi.org/10.2118/spe-169772-ms.
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Abstract One of the most intractable concerns when engineers try to reuse the produced water as frac fluid in the Bakken and some other shale plays is the scale formation caused by the incompatibility of produced water with additives in the frac fluids and with the formation. In order to obtain a more efficient scale treatment for a successful hydraulic fracing that handles the extraordinary amount of water with high supersaturation level, the better understanding of inhibitor retention and release in the production system is urgent. To explore the mechanism of attachment/release of phosphonate to/from a mineral surface, calcite supersaturated feed solutions with different diethylenetriamine penta (DTPMP) concentrations were introduced into the steel tubing that was internally pre-coated with a thin layer of CaCO3. It is unveiled that DTPMP attachment was dominated by the precipitation of calcium phosphonate solid once the solution is supersaturated with Ca3H4DTPMP (pKsp=53.5), and the total amount of DTPMP attached on the calcite surface added up with the increasing supersaturation of Ca3H4DTPMP. The co-precipitation of CaCO3 and Ca3H4DTPMP has facilitated the attachment of the inhibitor with the increase of supersaturation of CaCO3. The retained phosphonate was released from the surface with a steady and low level inhibitor concentration over extended period of time. Combining with the kinetics of calcium carbonate precipitation in the presence of inhibitor, a 1500 gram of calcium phosphonate precipitation can protect the scaling for about 100 days (100 bbl/day) when the saturation index of calcium carbonate (SIcalcite) is as high as 1.3. The results provide a better understanding of calcium-phosphonate-carbonate interaction, and show the phosphonate inhibitor can continuously accumulate on the carbonate and slowly dissolve. We anticipate this study can shed a light on how much inhibitor can be delivered to the unconventional reservoir as well as the theoretical limitation of inhibitor return in the flowback water.
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Yang, Yong, Hyoungsup Kim, Jin M. Jung, Alexander Fridman et Young I. Cho. « Application of Pulsed Spark Discharge for Mitigation of Mineral Fouling in a Heat Exchanger ». Dans 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-22392.
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One of the challenges in the production of electricity is the cooling water management because the calcium content in circulating cooling water continues to increase with time as pure water evaporates. Thus, the excessive mineral contents in water circulation systems could cause severe fouling in heat transfer equipment. To avoid the catastrophic failure in condensers, the cooling water is discharged after 3 cycles at a rate of 10 million gallons a day in a 1,000-MW thermoelectric power plant. The present study investigated the effect of pulsed spark discharges on the mitigation of mineral fouling in a concentric counterflow heat exchanger. Artificial hard water with calcium carbonate hardness ranging from 250 to 500 ppm was used with velocity varying over a range of 0.1–0.5 m/s and zero blowdown. Fouling resistances decreased by 50–88% for the plasma treated cases compared with the values for no-treatment cases. SEM photographs showed particle with larger sizes for the plasma treated cases comparing to smaller but more organized particles for the no-treatment cases. The different structures of particles were associated with pulsed spark discharge assisted precipitation of calcium carbonate in oversaturated hard water. X-ray diffraction data showed calcite crystal structures for all cases.
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Abdulvaliyev, R. A., et A. Akcil. « Change in the phase composition of low-quality bauxites as a result of chemical activation ». Dans Challenges of Science. Institute of Metallurgy and Ore Beneficiation, Satbayev University, 2021. http://dx.doi.org/10.31643/2021.10.
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As a result of separation of a fine fraction of gibbsite-kaolinite low-quality bauxite from the Krasnogorsky deposit, it is possible to increase its silicon module. When bauxite is chemically activated in a solution of sodium bicarbonate, the fine fraction is effectively separated from the large one and the phase composition changes – the calcium silicate phase disappears and the calcite phase is formed. With an increase in the activation temperature, the content of kaolinite and siderite decreases, the content of quartz and hematite increases. Studies have shown that at chemical activation temperatures of 120 oC, lasting more than 120 minutes and 200 oC, lasting more than 40 minutes, a dawsonite phase is formed in bauxite, which compacts the mineral structure. When determining the mode of chemical activation, it is necessary to take into account the negative possibility of the formation of dawsonite.
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Sulimai, N. H., Rozina Abdul Rani, Z. Khusaimi, S. Abdullah, M. J. Salifairus, Salman Alrokayan, Haseeb Khan et M. Rusop. « Calcite phase determination of CaCO3 nanoparticles synthesized by one step drying method ». Dans 8TH INTERNATIONAL CONFERENCE ON NANOSCIENCE AND NANOTECHNOLOGY 2017 (NANO-SciTech 2017). Author(s), 2018. http://dx.doi.org/10.1063/1.5036915.
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Popeski-Dimovski, Riste. « Optimized spray drying process for preparation of one-step calcium-alginate gel microspheres ». Dans 9TH INTERNATIONAL PHYSICS CONFERENCE OF THE BALKAN PHYSICAL UNION (BPU-9). AIP Publishing LLC, 2016. http://dx.doi.org/10.1063/1.4944310.
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Rao, Gundu H. R., et James G. White. « INFLUENCE OF CALCIUM FLUX ON STABILITY OF PLATELET MICROTUBULE COILS ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643904.
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Resting human platelets have a characteristic discoid form supported by a circumferential microtubule (MT). Ultrastructural, immunocytochemical and immunofluorescence studies have shown that the circumferential MT is a stable structure which undergoes constriction following exposure of platelets to aggregating agents. However, some biochemical and morphological studies suggested that MT coils dissolved almost completely within seconds after exposure to aggregating agents, then reassembled 1-4 minutes later. One investigation suggested that disappearance of the MT coils was associated with calcium flux caused by agonist stimulation or exposure to the ionophore, A23187. The present study has examined the latter hypothesis directly. Fura 2, a calcium sensitive fluorophore, was loaded into washed platelets at a concentration of 1 μM, the cells washed once and resuspended in HEPES buffer. Fluorescence changes were monitored in a Fluorolog spectrofluorometer.Thrombin stimulation of Fura 2 loaded platelets resulted in an immediate eight fold increase in the level of cytoplasmic calcium. The calcium ionophore, ionomycin, stimulated a 15 fold rise in the cytoplasmic calcium of Fura 2 loaded cells.Samples of thrombin and ionomycin stimulated platelets were fixed in glutaraldehyde and osmic acid at the peak of calcium flux indicated by the rise in fluorescence. Examination of activated platelets in the electron microscope revealed shape change and internal transformation. MT coils were constricted, but did not disappear from platelets fixed during the maximum elevation of cytoplasmic calcium. The findings do not support the concept that the calcium rise produced in platelets following exposure to potent agonists causes disappearance of the circumferential MT.
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Lu, Hung-Yun, Anil Bollimunta, Ryan W. Eaton, John H. Morrison, Karen A. Moxon, Jose M. Carmena, Jonathan J. Nassi et Samantha R. Santacruz. « Short-training Algorithm for Online Brain-machine Interfaces Using One-photon Microendoscopic Calcium Imaging ». Dans 2021 43rd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC). IEEE, 2021. http://dx.doi.org/10.1109/embc46164.2021.9629838.
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KÖhlin, A., et J. Stenflo. « HIGH AFFINITY CALCIUM BINDING TO DOMAINES OF PROTEIN C THAT ARE HOMOLOGUS TO THE EPIDERMAL GROWTH FACTOR ». Dans XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643645.
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In addition to γ-carboxyglutamic acid (Gla)-dependent calcium binding all of the vitamin K-dependent plasma proteins, except prothrombin, have one or two high affinity calcium binding sites that do not require the Gla residues. A common denominator among these proteins (factors IX, X, protein C, protein Z and protein S) is that they have domaines that are homologus to the epidermal growth factor (EGF) precursor. In factors VII,IX,X, protein C and in protein Z the aminoterminal of two EGF homology regions contain one residue of β-hydroxyaspartic acid (Hya) whereas in protein S the aminoterminal EGF homology region contains Hya and the three following contain one β-hydroxyasparagine residue each.In an attempt to elucidate the role of the EGF homology regions in the Gla independent calcium binding we have isolated a tryptic fragment (residue 44-138) from the light chain of human protein C. The fragment was isolated using a monoclonal antibody that recognizes a calcium ion stabilized epitope that is expressed both in intact protein C and in protein C lacking the Gla domaine.The antibody bound the isolated EGF homology region in the presence of calcium ions but not in EDTA containing buffer. A calcium ion titration showed half maximal binding at approximately 200 μM Ca2+. The metal ion induced conformational change in the isolated fragment was also studied with affinity purified rabbit antibodies against Gla domainless protein C. Antibodies that bound in the presence of calcium ions and that could be eluted with EDTA recognized the metal ion induced conformational change in the isolated EGF homology domain. Our results suggest that one or both of the EGF homology regions are involved in the Gla-independent high affinity calcium binding in the vitamin K-dependent plasma proteins.
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Mohamed, Abdelmjeed, Salaheldin Elkatatny et Salem Basfar. « One-Stage Calcium Carbonate Oil-Based Filter Cake Removal Using a New Biodegradable Acid System ». Dans SPE Kuwait Oil & Gas Show and Conference. Society of Petroleum Engineers, 2019. http://dx.doi.org/10.2118/198045-ms.
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Mohd Apandi, Nabila Wahida, et Mazlini Adnan. « Development of peri-calcup board kit as a form one teaching aids for perimeter topics ». Dans THE 3RD INTERNATIONAL CONFERENCE ON SCIENCE, MATHEMATICS, ENVIRONMENT, AND EDUCATION : Flexibility in Research and Innovation on Science, Mathematics, Environment, and education for sustainable development. AIP Publishing, 2023. http://dx.doi.org/10.1063/5.0106376.
Texte intégralRapports d'organisations sur le sujet "Onde calcio"
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Fromm, Hillel, et Joe Poovaiah. Calcium- and Calmodulin-Mediated Regulation of Plant Responses to Stress. United States Department of Agriculture, septembre 1993. http://dx.doi.org/10.32747/1993.7568096.bard.
Texte intégralRésumé :
We have taken a molecular approach to clone cellular targets of calcium/calmodulin (Ca2+/CaM). A 35S-labeled recombinant CaM was used as a probe to screen various cDNA expression libraries. One of the isolated clones from petunia codes for the enzyme glutamate decarboxylase (GAD) which catalyzes the conversion of glutamate to g-aminobutyric acid (GABA). The activity of plant GAD has been shown to be dramatically enhanced in response to cold and heat shock, anoxia, drought, mechanical manipulations and by exogenous application of the stress phytohormone ABA in wheat roots. We have purified the recombinant GAD by CaM-affinity chromatography and studied its regulation by Ca2+/CaM. At a physiological pH range (7.0-7.5), the purified enzyme was inactive in the absence of Ca2+ and CaM but could be stimulated to high levels of activity by the addition of exogenous CaM (K0.5 = 15 nM) in the presence of Ca2+ (K 0.5 = 0.8 mM). Neither Ca2+ nor CaM alone had any effect on GAD activity. Transgenic tobacco plants expressing a mutant petunia GAD lacking the CaM-binding domain, or transgenic plants expressing the intact GAD were prepared and studied in detail. We have shown that the CaM-binding domain is necessary for the regulation of glutamate and GABA metabolism and for normal plant development. Moreover, we found that CaM is tightly associated with a 500 kDa GAD complex. The tight association of CaM with its target may be important for the rapid modulation of GAD activity by Ca2+ signaling in response to stresses.
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Hinrichs, Claudia, et Judith Hauck. Report on skill of CMIP6 models to simulate alkalinity and improved parameterizations for large scale alkalinity distribution. OceanNets, juin 2022. http://dx.doi.org/10.3289/oceannets_d4.4.
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In part one of this deliverable, an ensemble of 14 CMIP6 Earth System Models is evaluated regarding their performance in simulating alkalinity and related parameters. The majority of the models and the multi-model-mean underestimate surface alkalinity compared to climatological observations. Alkalinity biases stemming from the parametrization of calcium carbonate formation and dissolution can be as big as biases stemming from model physics. In part two, we test the sensitivity of parametrizations concerning the carbonate chemistry in the FESOM2.1-REcoM3 and give recommendations for addressing alkalinity biases.
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Sink, Ken, Shamay Izhar et Abraham Nachmias. Asymmetric Somatic Hybridization : Developing a Gene Transfer System for Solanaceous Vegetable Crops. United States Department of Agriculture, février 1996. http://dx.doi.org/10.32747/1996.7613010.bard.
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Highly asymmetric somatic hybrid plants were obtained by PEG/DMSO fusion of gamma irradiated (100, 250, 7500 and 1000 Gy) protoplasts of a (KmR-) interspecific hybrid Lycopersicon esculentum x L. pennellii (EP) with protoplasts of eggplant (E). Somatic hybrid calli were selected based on kanamycin resistance and verified by PCR of the NptII gene, RAPD's and Southern's using potato rDNA pTHG2 probes. Flow cytometry indicated all hybrid calli that did not regenerate shoots were 5-9n. Three asymmetric plants regenerated only from callus close to 4n and such calli oly occurred when EP received 100 Gy. The asymmetric plants had eggplant morphology and regenerated from one hybrid callus with 6.29 average size tomato chromosomes. Limited amounts of EP DNA were found in the three somatic hybrid plants H18-1 to -3 by dot-blot hybridization with probe pTHG2, to be equivalent to 6.23, 5.41, and 5.95 % EP, respectively. RFLP analysis of Lycopersicon esculentum and L. pennellii specific chromosomes revealed that only fragments of 8 to 10 out of the 24 EP chromosomes are present in the asymmetric plants. Transgenic plants 2-3, 2-4 and 10-3 were found resistant to verticillium; suggesting successful transfer of the Ve complex from S. torvum to eggplant.
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Navarro, Gaston, Juan Pavlo Nicolini et Pedro Teles. Self-Fulfilling Debt Crises with Long Stagnations. Inter-American Development Bank, février 2023. http://dx.doi.org/10.18235/0004743.
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We assess the quantitative relevance of expectations-driven sovereign debt crises, focusing on the Southern European crisis of the early 2010s and the Argentine default of 2001. The source of multiplicity is the one in Calvo (1988). Key for multiplicity is an output process featuring long periods of either high growth or stagnation that we estimate using data for those countries. We find that expectations-driven debt crises are quantitatively relevant but state dependent, as they only occur during stagnations. Expectations are a major driver explaining default rates and credit spread differences between Spain and Argentina.
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Rafaeli, Ada, Russell Jurenka et Daniel Segal. Isolation, Purification and Sequence Determination of Pheromonotropic-Receptors. United States Department of Agriculture, juillet 2003. http://dx.doi.org/10.32747/2003.7695850.bard.
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Moths constitute a major group of pest insects in agriculture. Pheromone blends are utilised by a variety of moth species to attract conspecific mates, which is under circadian control by the neurohormone, PBAN (pheromone-biosynthesis-activating neuropeptide). Our working hypothesis was that, since the emission of sex-pheromone is necessary to attract a mate, then failure to produce and emit pheromone is a potential strategy for manipulating adult moth behavior. The project aimed at identifying, characterising and determining the sequence of specific receptors responsible for the interaction with pheromonotropic neuropeptide/s using two related moth species: Helicoverpa armigera and H. lea as model insects. We established specific binding to a membrane protein estimated at 50 kDa in mature adult females using a photoaffinity-biotin probe for PBAN. We showed that JH is required for the up-regulation of this putative receptor protein. In vitro studies established that the binding initiates a cascade of second messengers including channel opening for calcium ions and intracellular cAMP production. Pharmacological studies (using sodium fluoride) established that the receptor is coupled to a G-protein, that is, the pheromone-biosynthesis-activating neuropeptide receptor (PBAN-R) belongs to the family of G protein-coupled receptor (GPCR)'s. We showed that PBAN-like peptides are present in Drosophila melanogaster based on bioassay and immunocytochemical data. Using the annotated genome of D. melanogaster to search for a GPCR, we found that some were similar to neuromedin U- receptors of vertebrates, which contain a similar C-terminal ending as PBAN. We established that neuromedin U does indeed induce pheromone biosynthesis and cAMP production. Using a PCR based cloning strategy and mRNA isolated from pheromone glands of H. zea, we successfully identified a gene encoding a GPCR from pheromone glands. The full-length PBAN-R was subsequently cloned and expressed in Sf9 insect cells and was shown to mobilize calcium in response to PBAN in a dose-dependent manner. The successful progress in the identification of a gene, encoding a GPCR for the neurohormone, PBAN, provides a basis for the design of a novel battery of compounds that will specifically antagonize pheromone production. Furthermore, since PBAN belongs to a family of insect neuropeptides with more than one function in different life stages, this rationale may be extended to other physiological key-regulatory processes in different insects.
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Beckett-Brown, C. E., A. M. McDonald et M. B. McClenaghan. Discovering a porphyry deposit using tourmaline : a case study from Yukon. Natural Resources Canada/CMSS/Information Management, 2023. http://dx.doi.org/10.4095/331349.
Texte intégralRésumé :
As the exploration for porphyry Cu-Au-Mo deposits has become increasingly challenging, the development of more effective techniques directed at detecting buried deposits has become critical. One methodology is to focus on key minerals, one of which is tourmaline, a robust, ubiquitous mineral in most mineralized porphyry systems. Overall, a combination of physical and chemical characteristics including 1) macro-color, 2) morphology, 3) inclusion populations, and 4) trace-element compositions are useful in discriminating between porphyry- versus non-porphyry-derived (or related) tourmaline in surficial sediments (Beckett-Brown 2022). These features are applied to tourmaline obtained from stream sediment samples (n = 22) from 16 streams derived from the unglaciated terrain proximal to the Casino calc-alkaline porphyry Cu-Au-Mo deposit (Yukon Territory, Canada). The obtained tourmaline occurs as two distinct morphologies: 1) individual blocky to prismatic sub- to euhedral grains (Type 1), 2) aggregates of radiating prismatic to acicular sub- to euhedral grains (Type 2). Type 1 grains display trace-element contents that reflect mixed origins including a mineralized porphyry origin as well metamorphic and pegmatitic (background) environments. Type 2 grains almost exclusively exhibit porphyry-derived trace-element chemistries (i.e., high Sr/Pb ~150 avg. and relatively low Zn/Cu ~2.5 avg. values). In Canadian Creek, that directly drains from the Casino deposit, samples closest to the deposit contain >70% porphyry-derived tourmaline, while other streams in the region from unprospective drainage basins contain no porphyry-derived tourmaline. At the most distal sample site in Canadian Creek, ~20 km downstream from Casino, nearly 30% of the recovered tourmaline in the stream sediments is porphyry-related. This method has potential to be a strong indicator of prospectivity and applicable for exploration for porphyry Cu-Au-Mo systems in both unglaciated and glaciated terrains.
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Wilson, Charles, et Edo Chalutz. Biological Control of Postharvest Diseases of Citrus and Deciduous Fruit. United States Department of Agriculture, septembre 1991. http://dx.doi.org/10.32747/1991.7603518.bard.
Texte intégralRésumé :
The objectives of this research were to develop control measures of postharvest diseases of citrus and deciduous fruits by using naturally-occurring, non-antibiotic-producing antagonists; study the mode of action of effective antagonists and optimize their application methods. Several antagonists were found against a variety of diseases of fruits and vegetables. One particularly effective yeast antagonist (US-7) was chosen for more in-depth studies. This antagonist outcompetes rot pathogens at the wound site for nutrients and space; it is better adapted than the pathogen to extreme environmental conditions such as temperature, humidity and osmotic changes, and is relatively resistant to common postharvest fungicides. Our data suggests that other modes of action may also be involved. These are induction of host resistance by the antagonists or its products, and direct interaction between the antagonists and the pathogen with the possible involvement of an extracellular material and/or cell wall degrading enzymes produced by the antagonist. However, these interactions were not fully elucidated. The antagonistic activity of US-7 and other biocontrol agents isolated, was enhanced by calcium salts. While the mode of action is not known, the addition of these salts had a significant effect both in laboratory experiments and in large-scale tests. Compatibility of the yeast antagonist with present packinghouse treatments and procedures was determined. An integrated control procedure was developed, utilizing the antagonists together with ultra-low dosages of fungicides and activity-enhancing additives. This cooperative research resulted in numerous publications describing the antagonistic agents. their mode of action and possible commercial application. Patents were developed from this research and a commercial company is pursuing the licensing of these patents and the testing of the procedure on a commercial scale. Our research findings have expanded the potential for using non-antibiotic-producing antagonistic microorganisms in the control of postharvest diseases of fruits and vegetables; thus meeting a critical need to find alternatives to the use of synthetic fungicides on food products.
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Nelson, Nathan, et Charles F. Yocum. Structure, Function and Utilization of Plant Photosynthetic Reaction Centers. United States Department of Agriculture, septembre 2012. http://dx.doi.org/10.32747/2012.7699846.bard.
Texte intégralRésumé :
Light capturing and energy conversion by PSI is one of the most fundamental processes in nature. In the heart of these adaptations stand PSI, PSII and their light harvesting antenna complexes. The main goal of this grant proposal was to obtain by X-ray crystallography information on the structure of plant photosystem I (PSI) and photosystem II (PSII) supercomplexes. We achieved several milestones along this line but as yet, like several strong laboratories around the world, we have no crystal structure of plant PSII. We have redesigned the purification and crystallization procedures and recently solved the crystal structure of the PSI supercomplex at 3.3 Å resolution. Even though this advance in resolution appears to be relatively small, we obtained a significantly improved model of the supercomplex. The work was published in J. Biol. Chem. (Amunts et al., 2010). The improved electron density map yielded identification and tracing of the PsaK subunit. The location of an additional 10 ß-carotenes, as well as 5 chlorophylls and several loop regions that were previously uninterruptable have been modeled. This represents the most complete plant PSI structure obtained thus far, revealing the locations of and interactions among 17 protein subunits and 193 non-covalently bound photochemical cofactors. We have continued extensive experimental efforts to improve the structure of plant PSI and to obtain PSII preparation amenable to crystallization. Most of our efforts were devoted to obtain well-defined subcomplexes of plant PSII preparations that are amenable to crystallization. We studied the apparent paradox of the high sensitivity of oxygen evolution of isolated thylakoids while BBY particles exhibit remarkable resilience to the same treatment. The integrity of the photosystem II (PSII) extrinsic protein complement as well as calcium effects arise from the Ca2+ atom associated with the site of photosynthetic water oxidation were investigated. This work provides deeper insights into the interaction of PsbO with PSII. Sight-directed mutagenesis indicated the location of critical sites involved in the stability of the water oxidation reaction. When combined with previous results, the data lead to a more detailed model for PsbO binding in eukaryotic PSII.
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Lichter, Amnon, Gopi K. Podila et Maria R. Davis. Identification of Genetic Determinants that Facilitate Development of B. cinerea at Low Temperature and its Postharvest Pathogenicity. United States Department of Agriculture, mars 2011. http://dx.doi.org/10.32747/2011.7592641.bard.
Texte intégralRésumé :
Botrytis cinerea is the postharvest pathogen of many agricultural produce with table grapes, strawberries and tomatoes as major targets. The high efficiency with which B. cinerea causes disease on these produce during storage is attributed in part due to its exceptional ability to develop at very low temperature. Our major goal was to understand the genetic determinants which enable it to develop at low temperature. The specific research objectives were: 1. Identify expression pattern of genes in a coldenriched cDNA library. 2. Identify B. cinerea orthologs of cold-induced genes 3. Profile protein expression and secretion at low temperature on strawberry and grape supplemented media. 4. Test novel methods for the functional analysis of coldresponsive genes. Objective 1 was modified during the research because a microarray platform became available and it allowed us to probe the whole set of candidate genes according to the sequence of 2 strains of the fungus, BO5.10 and T4. The results of this experiment allowed us to validate some of our earlier observations which referred to genes which were the product of a SSH suppression-subtraction library. Before the microarray became available during 2008 we also analyzed the expression of 15 orthologs of cold-induced genes and some of these results were also validated by the microarray experiment. One of our goals was also to perform functional analysis of cold-induced genes. This goal was hampered for 3 years because current methodology for transformation with ‘protoplasts’ failed to deliver knockouts of bacteriordopsin-like (bR) gene which was our primary target for functional analysis. Consequently, we developed 2 alternative transformation platforms, one which involves an air-gun based technique and another which involves DNA injection into sclerotia. Both techniques show great promise and have been validated using different constructs. This contribution is likely to serve the scientific community in the near future. Using these technologies we generated gene knockout constructs of 2 genes and have tested there effect on survival of the fungus at low temperature. With reference to the bR genes our results show that it has a significant effect on mycelial growth of the B. cinerea and the mutants have retarded development at extreme conditions of ionic stress, osmotic stress and low temperature. Another gene of unknown function, HP1 is still under analysis. An ortholog of the yeast cold-induced gene, CCH1 which encodes a calcium tunnel and was shown to be cold-induced in B. cinerea was recently cloned and used to complement yeast mutants and rescue them from cold-sensitivity. One of the significant findings of the microarray study involves a T2 ribonuclease which was validated to be cold-induced by qPCR analysis. This and other genes will serve for future studies. In the frame of the study we also screened a population of 631 natural B. cinerea isolates for development at low temperature and have identified several strains with much higher and lower capacity to develop at low temperature. These strains are likely to be used in the future as candidates for further functional analysis. The major conclusions from the above research point to specific targets of cold-induced genes which are likely to play a role in cold tolerance. One of the most significant observations from the microarray study is that low temperature does not induce ‘general stress response in B. cinerea, which is in agreement to its exceptional capacity to develop at low temperature. Due to the tragic murder of the Co-PI Maria R. Davis and GopiPodila on Feb. 2010 it is impossible to deliver their contribution to the research. The information of the PI is that they failed to deliver objective 4 and none of the information which relates to objective 3 has been delivered to the PI before the murder or in a visit to U. Alabama during June, 2010. Therefore, this report is based solely on the IS data.
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Litaor, Iggy, James Ippolito, Iris Zohar et Michael Massey. Phosphorus capture recycling and utilization for sustainable agriculture using Al/organic composite water treatment residuals. United States Department of Agriculture, janvier 2015. http://dx.doi.org/10.32747/2015.7600037.bard.
Texte intégralRésumé :
Objectives: 1) develop a thorough understanding of the sorption mechanisms of Pi and Po onto the Al/O- WTR; 2) determine the breakthrough range of the composite Al/O-WTR during P capturing from agro- wastewaters; and 3) critically evaluate the performance of the composite Al/O-WTR as a fertilizer using selected plants grown in lysimeters and test-field studies. Instead of lysimeters we used pots (Israel) and one- liter cone-tainers (USA). We conducted one field study but in spite of major pretreatments the soils still exhibited high enough P from previous experiments so no differences between control and P additions were noticeable. Due to time constrains the field study was discontinued. Background: Phosphorous, a non-renewable resource, has been applied extensively in fields to increase crop yield, yet consequently has increased the potential of waterway eutrophication. Our proposal impetus is the need to develop an innovative method of P capturing, recycling and reuse that will sustain agricultural productivity while concurrently reducing the level of P discharge from and to agricultural settings. Major Conclusions & Achievements: An innovative approach was developed for P removal from soil leachate, dairy wastewater (Israel), and swine effluents (USA) using Al-based water treatment residuals (Al- WTR) to create an organic-Al-WTR composite (Al/O-WTR), potentially capable of serving as a P fertilizer source. The Al-WTR removed 95% inorganic-P, 80% to 99.9% organic P, and over 60% dissolved organic carbon from the agro-industrial waste streams. Organic C accumulation on particles surfaces possibly enhanced weak P bonding and facilitated P desorption. Analysis by scanning electron microscope (SEM- EDS), indicated that P was sparsely sorbed on both calcic and Al (hydr)oxide surfaces. Sorption of P onto WW-Al/O-WTR was reversible due to weak Ca-P and Al-P bonds induced by the slight alkaline nature and in the presence of organic moieties. Synchrotron-based microfocused X-ray fluorescence (micro-XRF) spectrometry, bulk P K-edge X-ray absorption near edge structure spectroscopy (XANES), and P K-edge micro-XANES spectroscopy indicated that adsorption was the primary P retention mechanism in the Al- WTR materials. However, distinct apatite- or octocalciumphosphatelike P grains were also observed. Synchrotron micro-XRF mapping further suggested that exposure of the aggregate exteriors to wastewater caused P to diffuse into the porous Al-WTR aggregates. Organic P species were not explicitly identified via P K-edge XANES despite high organic matter content, suggesting that organic P may have been predominantly associated with mineral surfaces. In screen houses experiments (Israel) we showed that the highest additions of Al/O-WTR (5 and 7 g kg⁻¹) produced the highest lettuce (Lactuca sativa L. var. longifolial) yield. Lettuce yield and P concentration were similar across treatments, indicating that Al/O- WTR can provide sufficient P to perform similarly to common fertilizers. A greenhouse study (USA) was utilized to compare increasing rates of swine wastewater derived Al/O-WTR and inorganic P fertilizer (both applied at 33.6, 67.3, and 134.5 kg P₂O₅ ha⁻¹) to supply plant-available P to spring wheat (TriticumaestivumL.) in either sandy loam or sandy clay loam soil. Spring wheat straw and grain P uptake were comparable across all treatments in the sandy loam, while Al/O-WTR application to the sandy clay loam reduced straw and grain P uptake. The Al/O-WTR did not affect soil organic P concentrations, but did increase phosphatase activity in both soils; this suggests that Al/O-WTR application stimulated microorganisms and enhance the extent to which microbial communities can mineralize Al/O-WTR-bound organic P. Implications: Overall, results suggest that creating a new P fertilizer from Al-WTR and agro-industrial waste sources may be a feasible alternative to mining inorganic P fertilizer sources, while protecting the environment from unnecessary waste disposal.