Accelerating Universe from an Evolving Lambda in Higher Dimension

We find exact solutions in five dimensional inhomogeneous matter dominated model with a varying cosmological constant. Adjusting arbitrary constants of integration one can also achieve acceleration in our model. Aside from an initial singularity our spacetime is regular everywhere including the centre of the inhomogeneous distribution. We also study the analogous homogeneous universe in (4+d) dimensions. Here an initially decelerating model is found to give late acceleration in conformity with the current observational demands. We also find that both anisotropy and number of dimensions have a role to play in determining the time of flip, in fact the flip is delayed in multidimensional models. Some astrophysical parameters like the age, luminosity distance etc are also calculated and the influence of extra dimensions is briefly discussed. Interestingly our model yields a larger age of the universe compared to many other quintessential models.Comment: 18 pages, 9 figure

Epidemiological And Genetic Characteristics Associated With The Severity Of Acute Viral Bronchiolitis By Respiratory Syncytial Virus

Objective: to assess the epidemiological and genetic factors associated with severity of acute viral bronchiolitis (AVB) by respiratory syncytial virus (RSV). Data source: the key words "bronchiolitis", "risk factor", "genetics" and "respiratory syncytial virus", and all combinations among them were used to perform a search in the PubMed, SciELO, and Lilacs databases, of articles published after the year 2000 that included individuals younger than 2 years of age. Data synthesis: a total of 1,259 articles were found, and their respective summaries were read. Of these, 81 were selected, which assessed risk factors for the severity of AVB, and were read in full; the 60 most relevant studies were included. The epidemiologic factors associated with AVB severity by RSV were prematurity, passive smoking, young age, lack of breastfeeding, chronic lung disease, congenital heart disease, male gender, ethnicity, viral coinfection, low weight at admission, maternal smoking during pregnancy, atopic dermatitis, mechanical ventilation in the neonatal period, maternal history of atopy and/or asthma during pregnancy, season of birth, low socioeconomic status, Down syndrome, environmental pollution, living at an altitude > 2,500 meters above sea level, and cesarean section birth. Conversely, some children with severe AVB did not present any of these risk factors. In this regard, recent studies have verified the influence of genetic factors on the severity of AVB by RSV. Polymorphisms of the TLRs, RANTES, JUN, IFNA5, NOS2, CX3CR1, ILs, and VDR genes have been shown to be associated with more severe evolution of AVB by RSV. Conclusion: the severity of AVB by RSV is a phenomenon that depends on the varying degrees of interaction among epidemiological, environmental, and genetic variables. © 2013 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.896531543Chávez-Bueno, S., Mejías, A., Welliver, R.C., Respiratory syncytial virus bronchiolitis: Current and future strategies for treatment and prophylaxis (2006) Treat Respir Med, 5, pp. 483-494Ogra, P.L., Respiratory syncytial virus: The virus, the disease and the immune response (2004) Paediatr Respir Rev, 5, pp. 119-S126Stockman, L.J., Curns, A.T., Anderson, L.J., Fischer-Langley, G., Respiratory syncytial virus-associated hospitalizations among infants and young children in the United States, 1997-2006 (2012) Pediatr Infect Dis J, 31, pp. 5-9Leader, S., Kohlhase, K., Recent trends in severe respiratory syncytial virus (RSV) among US infants, 1997 to 2000 (2003) J Pediatr, 143, pp. 127-S132Ranmuthugala, G., Brown, L., Lidbury, B.A., Respiratory syncytial virus - The unrecognised cause of health and economic burden among young children in Australia (2011) Commun Dis Intell, 35, pp. 177-184Simões, E.A., Carbonell-Estrany, X., Impact of severe disease caused by respiratory syncytial virus in children living in developed countries (2003) Pediatr Infect Dis J, 22, pp. 13-S18. , discussion S18-20Albernaz, E.P., Menezes, A.M., César, J.A., Victora, C.G., Barros, F.C., Halpern, R., Risk factors associated with hospitalization for bronchiolitis in the post-neonatal period (2003) Rev Saude Publica, 37, pp. 485-493Deshpande, S.A., Northern, V., The clinical and health economic burden of respiratory syncytial virus disease among children under 2 years of age in a defined geographical area (2003) Arch Dis Child, 88, pp. 1065-1069Fryzek, J.P., Martone, W.J., Groothuis, J.R., Trends in chronologic age and infant respiratory syncytial virus hospitalization: An 8-year cohort study (2011) Adv Ther, 28, pp. 195-201Sung, C.C., Chi, H., Chiu, N.C., Huang, D.T., Weng, L.C., Wang, N.Y., Viral etiology of acute lower respiratory tract infections in hospitalized young children in Northern Taiwan (2011) J Microbiol Immunol Infect, 44, pp. 184-190García, M.L., Ordobás Gabin, M., Calvo Reya, C., González Alvarez, M., Aguilar Ruiz, J., Arregui Sierra, A., Viral infection of the lower respiratory tract in hospitalized infants: Etiology, clinical features and risk factors (2001) An Esp Pediatr, 55, pp. 101-107Riccetto, A.G., Ribeiro, J.D., Silva, M.T., Almeida, R.S., Arns, C.W., Baracat, E.C., Respiratory syncytial virus (RSV) in infants hospitalized for acute lower respiratory tract disease: Incidence and associated risks (2006) Braz J Infect Dis, 10, pp. 357-361Salomão Junior, J.B., Gardinassi, L.G., Simas, P.V., Bittar, C.O., Souza, F.P., Rahal, P., Human respiratory syncytial virus in children hospitalized for acute lower respiratory infection (2011) J Pediatr (Rio J), 87, pp. 219-224Sly, P.D., Jones, C.M., Viral co-detection in infants hospitalized with respiratory disease: Is it important to detect? (2011) J Pediatr (Rio J), 87, pp. 277-280Miller, E.K., Williams, J.V., Gebretsadik, T., Carroll, K.N., Dupont, W.D., Mohamed, Y.A., Host and viral factors associated with severity of human rhinovirus-associated infant respiratory tract illness (2011) J Allergy Clin Immunol, 127, pp. 883-891Nascimento, M.S., Souza, A.V., Ferreira, A.V., Rodrigues, J.C., Abramovici, S., Silva Filho, L.V., High rate of viral identification and coinfections in infants with acute bronchiolitis (2010) Clinics (Sao Paulo), 65, pp. 1133-1137Groothuis, J.R., Fryzek, J.P., Makari, D., Steffey, D., Martone, W.J., Respiratory syncytial virus hospitalization trends in infants with chronic lung disease of infancy, 1998-2008 (2011) Clin Epidemiol, 3, pp. 245-250Gouyon, J.B., Rozé, J.C., Guillermet-Fromentin, C., Glorieux, I., Adamon, L., Di Maio, M., Hospitalizations for respiratory syncytial virus bronchiolitis in preterm infants at < 33 weeks gestation without bronchopulmonary dysplasia: The CASTOR study (2012) Epidemiol Infect, 15, pp. 1-11Semple, M.G., Taylor-Robinson, D.C., Lane, S., Smyth, R.L., Household tobacco smoke and admission weight predict severe bronchiolitis in infants independent of deprivation: Prospective cohort study (2011) PLoS One, 6, p. 22425Koehoorn, M., Karr, C.J., Demers, P.A., Lencar, C., Tamburic, L., Brauer, M., Descriptive epidemiological features of bronchiolitis in a population-based cohort (2008) Pediatrics, 122, pp. 1196-1203Ochoa Sangrador, C., González De Dios, J., Idoneidad y Adecuación). Consensus conference on acute bronchiolitis (VI): Prognosis of acute bronchiolitis. Review of scientific evidence (2010) An Pediatr (Barc), 72 (354), pp. e1-3634. , Grupo de Revisión del Proyecto aBREVIADo (BRonquiolitis-Estudio de VariabilidadGrimwood, K., Cohet, C., Rich, F.J., Cheng, S., Wood, C., Redshaw, N., Risk factors for respiratory syncytial virus bronchiolitis hospital admission in New Zealand (2008) Epidemiol Infect, 136, pp. 1333-1341López Guinea, A., Casado Flores, J., Martín Sobrino, M.A., Espínola Docio, B., De La Calle Cabrera, T., Serrano, A., García Teresa, M.A., Severe bronchiolitis. Epidemiology and clinical course of 284 patients (2007) An Pediatr (Barc), 67, pp. 116-122Chan, P.W., Lok, F.Y., Khatijah, S.B., Risk factors for hypoxemia and respiratory failure in respiratory syncytial virus bronchiolitis (2002) Southeast Asian J Trop Med Public Health, 33, pp. 806-810Garcia, C.G., Bhore, R., Soriano-Fallas, A., Trost, M., Chason, R., Ramilo, O., Mejias, A., Risk factors in children hospitalized with RSV bronchiolitis versus non-RSV bronchiolitis (2010) Pediatrics, 126, pp. 1453-e1460Chatzimichael, A., Tsalkidis, A., Cassimos, D., Gardikis, S., Tripsianis, G., Deftereos, S., The role of breastfeeding and passive smoking on the development of severe bronchiolitis in infants (2007) Minerva Pediatr, 59, pp. 199-206Jones, L.L., Hashim, A., McKeever, T., Cook, D.G., Britton, J., Leonardi-Bee, J., Parental and household smoking and the increased risk of bronchitis, bronchiolitis and other lower respiratory infections in infancy: Systematic review and meta-analysis (2011) Respir Res, 12, p. 5Bradley, J.P., Bacharier, L.B., Bonfiglio, J., Schechtman, K.B., Strunk, R., Storch, G., Severity of respiratory syncytial virus bronchiolitis is affected by cigarette smoke exposure and atopy (2005) Pediatrics, 115, pp. 7-e14Hervás, D., Reina, J., Yañez, A., Del Valle, J.M., Figuerola, J., Hervás, J.A., Epidemiology of hospitalization for acute bronchiolitis in children: Differences between RSV and non-RSV bronchiolitis (2012) Eur J Clin Microbiol Infect Dis, 31, pp. 1975-1981Oñoro, G., Pérez Suárez, E., Iglesias Bouzas, M.I., Serrano, A., Martínez De Azagra, A., Severe bronchiolitis. Changes in epidemiology and respiratory support (2011) An Pediatr (Barc), 74, pp. 371-376Damore, D., Mansbach, J.M., Clark, S., Ramundo, M., Camargo Jr., C.A., Prospective multicenter bronchiolitis study: Predicting intensive care unit admissions (2008) Acad Emerg Med, 15, pp. 887-894Papoff, P., Moretti, C., Cangiano, G., Bonci, E., Roggini, M., Pierangeli, A., Incidence and predisposing factors for severe disease in previously healthy term infants experiencing their first episode of bronchiolitis (2011) Acta Paediatr, 100, pp. 17-e23Vidaurreta, S.M., Marcone, D.N., Ellis, A., Ekstrom, J., Cukier, D., Videla, C., Acute viral respiratory infection in children under 5 years: Epidemiological study in two centers in Buenos Aires, Argentina (2011) Arch Argent Pediatr, 109, pp. 296-304Dornelles, C.T., Piva, J.P., Marostica, P.J., Nutritional status, breastfeeding, and evolution of infants with acute viral bronchiolitis (2007) J Health Popul Nutr, 25, pp. 336-343Al-Shehri, M.A., Sadeq, A., Quli, K., Bronchiolitis in Abha, Southwest Saudi Arabia: Viral etiology and predictors for hospital admission (2005) West Afr J Med, 24, pp. 299-304Che, D., Nicolau, J., Bergounioux, J., Perez, T., Bitar, D., Bronchiolitis among infants under 1 year of age in France: Epidemiology and factors associated with mortality (2012) Arch Pediatr, 19, pp. 700-706Fjaerli, H.O., Farstad, T., Bratlid, D., Hospitalisations for respiratory syncytial virus bronchiolitis in Akershus, Norway, 1993-2000: A population-based retrospective study (2004) BMC Pediatr, 4, p. 25Meissner, H.C., Selected populations at increased risk from respiratory syncytial virus infection (2003) Pediatr Infect Dis J, 22, pp. 40-S45Riccetto, A.G., Silva, L.H., Spilki, F.R., Morcillo, A.M., Arns, C.W., Baracat, E.C., Genotypes and clinical data of respiratory syncytial virus and metapneumovirus in Brazilian infants: A new perspective (2009) Braz J Infect Dis, 13, pp. 35-39D'Elia, C., Siqueira, M.M., Portes, S.A., Sant'Anna, C.C., Respiratory syncytial virus - Associated lower respiratory tract infections in hospitalized infants (2005) Rev Soc Bras Med Trop, 38, pp. 7-10Weigl, J.A., Puppe, W., Schmitt, H.J., Variables explaining the duration of hospitalization in children under two years of age admitted with acute airway infections: Does respiratory syncytial virus have a direct impact? (2004) Klin Padiatr, 216, pp. 7-15Brand, H.K., De Groot, R., Galama, J.M., Brouwer, M.L., Teuwen, K., Hermans, P.W., Infection with multiple viruses is not associated with increased disease severity in children with bronchiolitis (2012) Pediatr Pulmonol, 47, pp. 393-400De Paulis, M., Gilio, A.E., Ferraro, A.A., Ferronato, A.E., Do Sacramento, P.R., Botosso, V.F., Severity of viral coinfection in hospitalized infants with respiratory syncytial virus infection (2011) J Pediatr (Rio J), 87, pp. 307-313Jartti, T., Söderlund-Venermo, M., Hedman, K., Ruuskanen, O., Mäkelä, M.J., New molecular virus detection methods and their clinical value in lower respiratory tract infections in children (2013) Paediatr Respir Rev, 14, pp. 38-45Carroll, K.N., Gebretsadik, T., Griffin, M.R., Dupont, W.D., Mitchel, E.F., Wu, P., Maternal asthma and maternal smoking are associated with increased risk of bronchiolitis during infancy (2007) Pediatrics, 119, pp. 1104-1112Bloemers, B.L., Van Furth, A.M., Weijerman, M.E., Gemke, R.J., Broers, C.J., Van Den Ende, K., Down syndrome: A novel risk factor for respiratory syncytial virus bronchiolitis - A prospective birth-cohort study (2007) Pediatrics, 120, pp. 1076-e1081Karr, C., Lumley, T., Schreuder, A., Davis, R., Larson, T., Ritz, B., Effects of subchronic and chronic exposure to ambient air pollutants on infant bronchiolitis (2007) Am J Epidemiol, 165, pp. 553-560Choudhuri, J.A., Ogden, L.G., Ruttenber, A.J., Thomas, D.S., Todd, J.K., Simoes, E.A., Effect of altitude on hospitalizations for respiratory syncytial virus infection (2006) Pediatrics, 117, pp. 349-356Moore, H.C., De Klerk, N., Holt, P., Richmond, P.C., Lehmann, D., Hospitalisation for bronchiolitis in infants is more common after elective caesarean delivery (2012) Arch Dis Child, 97, pp. 410-414Thomsen, S.F., Stensballe, L.G., Skytthe, A., Kyvic, K.O., Backer, V., Bisgaard, H., Increased concordance of severe respiratory syncytial virus infection in identical twins (2008) Pediatrics, 121, pp. 493-496Tal, G., Mandelberg, A., Dalal, I., Cesar, K., Somekh, E., Tal, A., Association between common Toll-like receptor 4 mutations and severe respiratory syncytial virus disease (2004) J Infect Dis, 189, pp. 2057-2063Douville, R.N., Lissitsyn, Y., Hirschfeld, A.F., Becker, A.B., Kozyrskyj, A.L., Liem, J., TLR4 Asp299Gly and Thr399Ile polymorphisms: No impact on human immune responsiveness to LPS or respiratory syncytial virus (2010) PLoS One, 5, p. 12087Löfgren, J., Marttila, R., Renko, M., Rämet, M., Hallman, M., Toll-like receptor 4 Asp299Gly polymorphism in respiratory syncytial virus epidemics (2010) Pediatr Pulmonol, 45, pp. 687-692Mandelberg, A., Tal, G., Naugolny, L., Cesar, K., Oron, A., Houri, S., Lipopolysaccharide hyporesponsiveness as a risk factor for intensive care unit hospitalization in infants with respiratory syncitial virus bronchiolitis (2006) Clin Exp Immunol, 144, pp. 48-52Puthothu, B., Forster, J., Heinzmann, A., Krueger, M., TLR-4 and CD14 polymorphisms in respiratory syncytial virus associated disease (2006) Dis Markers, 22, pp. 303-308Mailaparambil, B., Krueger, M., Heinze, J., Forster, J., Heinzmann, A., Polymorphisms of toll like receptors in the genetics of severe RSV associated diseases (2008) Dis Markers, 25, pp. 59-65Amanatidou, V., Sourvinos, G., Apostolakis, S., Neonaki, P., Tsilimigaki, A., Krambovitis, E., RANTES promoter gene polymorphisms and susceptibility to severe respiratory syncytial virus-induced bronchiolitis (2008) Pediatr Infect Dis J, 27, pp. 38-42Kresfelder, T.L., Janssen, R., Bont, L., Venter, M., Confirmation of an association between single nucleotide polymorphisms in the VDR gene with respiratory syncytial virus related disease in South African children (2011) J Med Virol, 83, pp. 1834-1840Janssen, R., Bont, L., Siezen, C.L., Hodemaekers, H.M., Ermers, M.J., Doornbos, G., Genetic susceptibility to respiratory syncytial virus bronchiolitis is predominantly associated with innate immune genes (2007) J Infect Dis, 196, pp. 826-834Amanatidou, V., Sourvinos, G., Apostolakis, S., Tsilimigaki, A., Spandidos, D.A., T280 M variation of the CX3C receptor gene is associated with increased risk for severe respiratory syncytial virus bronchiolitis (2006) Pediatr Infect Dis J, 25, pp. 410-414Ampuero, S., Luchsinger, V., Tapia, L., Palomino, M.A., Larrañaga, C.E., SP-A1, SP-A2 and SP-D gene polymorphisms in severe acute respiratory syncytial infection in Chilean infants (2011) Infect Genet Evol, 11, pp. 1368-1377Mulet, J.F., Rodríguez De Torres, B.O., Viral induced bronchiolitis and genetics (2010) An Pediatr (Barc), 73, pp. 159-16

Efeito de fontes e de aditivos na absorção de 35S via foliar pelo feijoeiro

A greenhouse experiment was carried out with the aim of evaluating the effect of sulphur sources, in the presence or absence of additives (urea and glucose), on the sulphur uptake by bean leaves. The treatments: solutions of sulphuric acid, ammonium, potassium, magnesium, manganese and zinc sulphates labelled with 35S, containing or not the additives, were applied to the first trifoliate of the plants to assess the sulphur uptake and translocation. The results enable to conclude that 33% of the added sulphur was absorved, and 27% out of this total was translocated. The additives did not have any influence on uptake and translocation. The sulphuric acid and ammonium sulphate solutions were the best sulphur suppliers for the bean plant.Foi conduzido em casa de vegetação um experimento com o objetivo de avaliar o efeito de fontes de enxofre, na presença ou não de aditivos (uréia e glicose), sobre a absorção do demento pelas folhas de feijoeiro. Os tratamentos: soluções de ácido sulfúrico e de sulfates de amonio, potássio, magnésio, manganês e zinco marcadas com 35S, contendo ou não os aditivos, foram aplicados ao primeiro trifólio das plantas para avaliar a absorção e translocação de enxofre. Os resultados permitiram concluir que 33% do S adicionado foi absorvido, e desse total 27% foi translocado, não havendo influência dos aditivos sobre esses processos. O ácido sulfúrico e o sulfato de amonio destacaram-se como os melhores fornecedores de enxofre, via foliar, para o feijoeiro

A Biased Review of Sociophysics

Various aspects of recent sociophysics research are shortly reviewed: Schelling model as an example for lack of interdisciplinary cooperation, opinion dynamics, combat, and citation statistics as an example for strong interdisciplinarity.Comment: 16 pages for J. Stat. Phys. including 2 figures and numerous reference

Determining the density of states for classical statistical models: A random walk algorithm to produce a flat histogram

We describe an efficient Monte Carlo algorithm using a random walk in energy space to obtain a very accurate estimate of the density of states for classical statistical models. The density of states is modified at each step when the energy level is visited to produce a flat histogram. By carefully controlling the modification factor, we allow the density of states to converge to the true value very quickly, even for large systems. This algorithm is especially useful for complex systems with a rough landscape since all possible energy levels are visited with the same probability. In this paper, we apply our algorithm to both 1st and 2nd order phase transitions to demonstrate its efficiency and accuracy. We obtained direct simulational estimates for the density of states for two-dimensional ten-state Potts models on lattices up to $200 \times 200$ and Ising models on lattices up to $256 \times 256$. Applying this approach to a 3D $\pm J$ spin glass model we estimate the internal energy and entropy at zero temperature; and, using a two-dimensional random walk in energy and order-parameter space, we obtain the (rough) canonical distribution and energy landscape in order-parameter space. Preliminary data suggest that the glass transition temperature is about 1.2 and that better estimates can be obtained with more extensive application of the method.Comment: 22 pages (figures included

Health-related fitness as a predictor of anxiety levels among school adolescents: an observational cross-sectional study

Background: There is an inverse association between cardiorespiratory fitness and general anxiety levels in adolescents. Obesity also is associated with a higher risk of anxiety in this population. However, little is known about the association between other health-related fitness elements with anxiety symptoms in this population. The authors explored the relationship between health-related fitness and anxiety symptoms in a large sample of Brazilian youth. Methods: This was an observational cross-sectional study with a sample comprised of 257 school adolescents, who were 136 girls (52.9%) and 121 boys (47.1%). The health-related fitness elements were evaluated by FitnessGram® test and anxiety levels by Multidimensional Anxiety Scale for Children - 39. Hierarchical regression analyses were used to determine the association between health-related fitness elements and anxiety symptoms in both sexes. Results: In male adolescents, only the cardiorespiratory fitness was significantly associated with anxiety symptoms (F(1, 119) = 6.472; P = 0.012; R2 = 0.052; adjusted R2 = 0.044). In turn, the anxiety symptoms showed an inverse small relationship with cardiorespiratory fitness (r = - 0.227; P < 0.01). However, in female adolescents, no association was found between health-related fitness elements and anxiety symptoms. Conclusion: The level of cardiorespiratory fitness may represent a marker of anxiety in male adolescents

Adubos verdes e seus efeitos no rendimento da cana-de-açúcar em sistema de plantio direto.

O objetivo deste trabalho foi avaliar adubos verdes e seus efeitos no rendimento da cana-de-açúcar em sistema de plantio direto (SPD). O trabalho foi realizado em Campos dos Goytacazes (RJ), no período de dezembro de 2003 a julho de 2005. O delineamento experimental foi em blocos casualizados, com quatro repetições. Os tratamentos foram: feijão-de-porco (Canavalia ensiformis), mucuna-preta(Mucuna aterrimum), crotalária (Crotalária juncea) em plantio direto e vegetação espontânea em preparo convencional (testemunha). Com crotalária aos 35 dias após emergência (DAE) houve maior taxa de cobertura do solo – 87% – e, aos 92 DAE produziu 17.852 kg ha-1 de matéria seca, respectivamente, 41%, 78% e 407% superior ao feijão-de-porco, mucuna e vegetação espontânea, além de superá-las em acúmulos de K, Mg, S, Zn e Fe. O feijão-de-porco e a mucuna proporcionaram o maior teor de N na parte aérea. Com feijão-de-porco, os teores de P e Ca foram maiores que a crotalária e a mucuna. Com vegetação espontânea, o maior teor de K foi na parte aérea. As leguminosas acumularam maiores quantidades de N e Cu do que a vegetação espontânea. A crotalária e o feijão-de-porco acumularam 66% a mais de P na parte área que a mucuna. O SPD utilizando a adubação verde contribuiu significativamente para a maior produtividade de cana-de-açúcar, 135.863 kg ha-1, sendo 37% superior ao PC com a vegetação espontânea

Cosmological Dynamics of Phantom Field

We study the general features of the dynamics of the phantom field in the cosmological context. In the case of inverse coshyperbolic potential, we demonstrate that the phantom field can successfully drive the observed current accelerated expansion of the universe with the equation of state parameter $w_{\phi} < -1$. The de-Sitter universe turns out to be the late time attractor of the model. The main features of the dynamics are independent of the initial conditions and the parameters of the model. The model fits the supernova data very well, allowing for $-2.4 < w_{\phi} < -1$ at 95 % confidence level.Comment: Typos corrected. Some clarifications and references added. To appear in Physical Review

Actividad antioxidante y polifenoles de las algas marinas halimeda opuntia y halimeda monile

En este trabajo se estudió la actividad antioxidante de dos especies de algas marinas (H. opuntia y H. monile) mediante el ensayo de atrapamiento de radicales DPPH• y el sistema β-Caroteno-acido linoleico. Adicionalmente a las fracciones de ácidos fenolicos libres, ésteres solubles y ésteres insolubles de ácidos fenólicos se les determinó el contenido en fenoles totales mediante la técnica de Folin-Ciocalteu y posteriormente se identificaron y cuantificaron 8 ácidos fenólicos y cinámicos, resultando el componente mayoritario el ácido salicílico. En los ensayos utilizados se obtuvieron valores altos de actividad antioxidante para las diferentes fracciones. A partir de estos resultados se puede postular que la actividad antioxidante de los extractos polares de estas algas pudiera ser explicada, al menos parcialmente, por la presencia de los ácidos fenólicos y cinámicos. En el caso del alga Halimeda monile, de acuerdo con la literatura consultada, es el primer reporte de la actividad antioxidante.In this paper, the antioxidant activity displayed by two different green seaweed species (H. opuntia y H. monile) was studied using the β- carotene/ linoleic acid and the DPPH• scavenging.systems as different experimental in vitro antioxidant assessment models. Polar seaweed fractions containing free phenolic acids, soluble esters and insoluble esters of phenolic acids were chemically characterized in terms of their phenolic content and composition. In that direction, 8 phenolic acids were identified and quantified, and salycilic acid was shown to be the majoritary compound on the fractions from both species. In addition, the polar fractions were proved to exert antioxidant activity in the two used experimental systems with considerably low values of CI50. Thus, in view of these findings, the antioxidant activity of these polar Halimeda spp. extracts could be supported and at least partially related to the presence of phenolic acids. In case of Halimeda monile this is, at least to the extend of our knowledge, the first report of such biological activity