Stability of the monoclinic phase in the ferroelectric perovskite PbZr(1-x)TixO3

Recent structural studies of ferroelectric PbZr(1-x)TixO3 (PZT) with x= 0.48, have revealed a new monoclinic phase in the vicinity of the morphotropic phase boundary (MPB), previously regarded as the the boundary separating the rhombohedral and tetragonal regions of the PZT phase diagram. In the present paper, the stability region of all three phases has been established from high resolution synchrotron x-ray powder diffraction measurements on a series of highly homogeneous samples with 0.42 <=x<= 0.52. At 20K the monoclinic phase is stable in the range 0.46 <=x<= 0.51, and this range narrows as the temperature is increased. A first-order phase transition from tetragonal to rhombohedral symmetry is observed only for x= 0.45. The MPB, therefore, corresponds not to the tetragonal-rhombohedral phase boundary, but instead to the boundary between the tetragonal and monoclinic phases for 0.46 <=x<= 0.51. This result provides important insight into the close relationship between the monoclinic phase and the striking piezoelectric properties of PZT; in particular, investigations of poled samples have shown that the monoclinic distortion is the origin of the unusually high piezoelectric response of PZT.Comment: REVTeX file, 7 figures embedde

Photoacoustic Measurement Of The Thermal Properties Of Two-layer Systems

Using two different photoacoustic techniques for a two-layer system of variable thickness, we show that the thermal diffusivity and the thermal conductivity are completely determined, based upon the effective-sample model widely used in heat-transfer problems. A procedure to establish a standard photothermal technique for measuring both the thermal diffusivity and the thermal conductivity is also discussed. © 1990 The American Physical Society.4274477448

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Cardiovascular Responses To Postural Change And Aerobic Capacity In Middle-aged Men And Women Before And After Aerobic Physical Training

Objective: To compare the cardiovascular responses to passive postural maneuvers (tilt test) and the cardiorespiratory capacity in middle-aged men and women, before and after aerobic physical training. Methods: Seven men (44.6±2.1 years old) and seven women (51.7±4.8 years old) participated in aerobic physical training for 12 weeks. The tilt test protocol (five minutes supine, ten minutes tilted at 70° and five minutes supine) was followed, with arterial blood pressure and heart rate monitoring. A cycle ergometer protocol was used to measure cardiorespiratory capacity. Results: In the sedentary condition, men showed greater parasympathetic influence in heart rate control, as demonstrated by their higher RR interval (iRR) during the tilt test. After training, the iRR values became more similar in the two groups, although the women had higher iRR in the supine position and the men continued to present higher iRR under tilted conditions. The women's blood pressures continued to be higher after training, but heart rate tended to become similar in the two groups. The cardiorespiratory capacity patterns in the two groups were similar after training. Except for absolute heart rate values, for which there were no differences between the groups, the men's values were higher than those of the women for all other variables. It was also observed that, after the training, the women's blood pressures were significantly lower, even though their pressures remained higher than the men's. Conclusions: The training seemed to reduce the women's arterial blood pressure levels and improve both groups' cardiorespiratory capacity, but the men continued to present better performance than the women.125392400Pollock, M.L., Dawson, G.A., Physiologic responses of men 49 to 65 years of age to endurance training (1976) J Am Geriatr Soc, 24 (3), pp. 97-104Haddock, B.L., Marshak, H.P.H., Mason, J.J., Blix, G., The effect of hormone replacement therapy and exercise on cardiovascular disease risk factors in postmenopausal women (2000) Sports Med, 29 (1), pp. 39-49Liu, C.C., Kuo, T.B., Yang, C.C., Effects of estrogen on gender-related autonomic differences in humans (2003) Am J Physiol Heart Circ Physiol, 285 (5), pp. H2188-H2193Rosano, G.M., Vitale, C., Fini, M., Hormone replacement therapy and cardioprotection: What is good and what is bad for the cardiovascular system? (2006) Ann. N.Y. Acad Sci, 1092, pp. 341-348Ghorayeb N, Baptista CA, Dioguardi GS, Reginatto LE. Atividade física na mulher. Rev Soc Cardiol Est São Paulo, SOCESP.1996;6:540-2Kannel, W.B., Hjortland, M.C., McNamara, P.M., Gordon, T., Menopause and risk of cardiovascular disease: The Framingham study (1976) Ann Intern Med, 85 (4), pp. 447-452Tank, J., Does aging cause women to be more sympathetic than men? (2005) Hypertension, 45 (4), pp. 489-490Kuttenn, F., Gerson, M., Hormone replacement therapy of menopause, heart and blood vessels (2001) Arch Mal Coeur Vaiss, 94 (7), pp. 685-689Vanoli, E., De Ferrari, G.M., Stramba-Badiale, M., Hull Jr, S.S., Foreman, R.D., Schwartz, P.J., Vagal stimulation and prevention of sudden death in conscious dogs with a healed myocardial infarction (1991) Circ Res, 68 (5), pp. 1471-1481Smith, J.J., Kampine, J.P., (1990) Regulation of arterial blood pressure, , editores. Circulatory physiology, the essentials. 3aed. Baltimore: Williams &ampWilkins;Kuo, T.B., Lin, T., Yang, C.C., Li, C.L., Chen, C.F., Chou, P., Effect of aging on gender differences in neural control of heart rate (1999) Am J Physiol, 277 (6 PART 2), pp. H2233-H2239Evans, J.M., Ziegler, M.G., Patwardhan, A.R., Ott, J.B., Kim, C.S., Leonelli, F.M., Gender differences in autonomic cardiovascular regulation: Spectral, hormonal, and hemodynamic indexes (2001) J Appl Physiol, 91 (6), pp. 2611-2618Pikkujämsä, S.M., Mäkikallio, T.H., Airaksinen, K.E., Huikuri, H.V., Determinants and interindividual variation of R-R interval dynamics in healthy middle-aged subjects (2001) Am J Physiol Heart Circ Physiol, 280 (3), pp. H1400-H1406Neves, V.F., Silva de, S.M., Gallo Jr, L., Catai, A.M., Martins, L.E., Crescêncio, J.C., Autonomic modulation of heart rate of young and postmenopausal women undergoing estrogen therapy (2007) Braz J Med Biol Res, 40 (4), pp. 491-499(2005) ACSM's guidelines for exercise testing and prescription/ACSM, , American College of Sports Medicine, Philadelphia: Lippincott Williams & Wilkins;Maciel, B.C., Gallo Júnior, L., Marin Neto, J.A., Lima Filho, E.C., Terra Filho, J., Manço, J.C., Parasympathetic contribution to bradycardia induced by endurance training in man (1985) Cardiovasc Res, 19 (10), pp. 642-648Martinelli, F.S., (1996) Respostas da freqüência cardíaca e da pressão arterial sistêmica às manobras postural passiva e de valsalva, em indivíduos sedentários e atletas corredores de longa distância, , dissertação, Campinas: Unicamp;Goldsmith, R.L., Bigger Jr, J.T., Steinman, R.C., Fleiss, J.L., Comparison of 24-hour parasympathetic activity in endurance-trained and untrained young men (1992) J Am Coll. Cardiol, 20 (3), pp. 552-558Shin, K., Minamitani, H., Onishi, S., Yamazaki, H., Lee, M., Autonomic differences between athletes and nonathletes: Spectral analysis approach (1997) Med Sci Sports Exerc, 29 (11), pp. 1482-1490Seals, D.R., Taylor, J.A., Ng, A.V., Esler, M.D., Exercise and aging: Autonomic control of the circulation (1994) Med Sci Sports Exerc, 26 (5), pp. 568-576Chacon-Mikahil, M.P.T., (1998) Estudo da variabilidade da freqüência cardíaca nos domínios do tempo e da freqüência antes e após o treinamento aeróbio em homens de meia idade [tese], , Campinas: Unicamp;Laitinen, T., Niskanen, L., Geelen, G., Länsimies, E., Hartikainen, J., Age dependency of cardiovascular autonomic responses to head-up tilt test in healthy subjects (2004) J Appl Physiol, 96 (6), pp. 2333-2340Gordon, C.C., Chumlea, W.C., Roche, A.F., Stature, Recumbent Length, Weight (1988) Anthropometric standardizing reference manual, pp. 3-8. , Lohman TG et al, editores, Champaign, Illinois: Human Kinetics Books;Wasserman, K., Whipp, B.J., Koyl, S.N., Beaver, W.L., Anaerobic threshold and respiratory gas exchange during exercise (1973) J Appl Physiol, 35 (2), pp. 236-243Montano, N., Ruscone, T.G., Porta, A., Lombardi, F., Pagani, M., Malliani, A., Power spectrum analysis of heart rate variability to assess the changes in sympathovagal balance during graded orthostatic tilt (1994) Circulation, 90 (4), pp. 1826-1831Shoemaker, J.K., Hogeman, C.S., Khan, M., Kimmerly, D.S., Sinoway, L.I., Gender affects sympathetic and hemodynamic response to postural stress (2001) Am J Physiol Heart Circ Physiol, 281 (5), pp. H2028-H2035Bigger Jr, J.T., Fleiss, J.L., Steinman, R.C., Rolnitzky, L.M., Kleiger, R.E., Rottman, J.N., Correlations among time and frequency domain measures of heart period variability two weeks after acute myocardial infarction (1992) Am J Cardiol, 69 (9), pp. 891-898Almeida, M.B.E., Araújo, C.G.S., Effects of aerobic training on heart rate (2003) Rev Bras Med Esporte, 9 (2), pp. 113-120Yataco, A.R., Fleisher, L.A., Katzel, L.I., Heart rate variability and cardiovascular fitness in senior athletes (1997) Am J Cardiol, 80 (10), pp. 1389-1391Rennie, K.L., Hemingway, H., Kumari, M., Brunner, E., Malik, M., Marmot, M., Effects of moderate and vigorous physical activity on heart rate variability in a British study of civil servants (2003) Am J Epidemiol, 158 (2), pp. 135-14

Understanding and engineering beneficial plant–microbe interactions:Plant growth promotion in energy crops

Plant production systems globally must be optimized to produce stable high yields from limited land under changing and variable climates. Demands for food, animal feed, and feedstocks for bioenergy and biorefining applications, are increasing with population growth, urbanization and affluence. Low-input, sustainable, alternatives to petrochemical-derived fertilizers and pesticides are required to reduce input costs and maintain or increase yields, with potential biological solutions having an important role to play. In contrast to crops that have been bred for food, many bioenergy crops are largely undomesticated, and so there is an opportunity to harness beneficial plant–microbe relationships which may have been inadvertently lost through intensive crop breeding. Plant–microbe interactions span a wide range of relationships in which one or both of the organisms may have a beneficial, neutral or negative effect on the other partner. A relatively small number of beneficial plant–microbe interactions are well understood and already exploited; however, others remain understudied and represent an untapped reservoir for optimizing plant production. There may be near-term applications for bacterial strains as microbial biopesticides and biofertilizers to increase biomass yield from energy crops grown on land unsuitable for food production. Longer term aims involve the design of synthetic genetic circuits within and between the host and microbes to optimize plant production. A highly exciting prospect is that endosymbionts comprise a unique resource of reduced complexity microbial genomes with adaptive traits of great interest for a wide variety of applications

Measurement of the correlation between flow harmonics of different order in lead-lead collisions at √sNN = 2.76 TeV with the ATLAS detector

Correlations between the elliptic or triangular flow coefficients vm (m=2 or 3) and other flow harmonics vn (n=2 to 5) are measured using √sNN=2.76 TeV Pb+Pb collision data collected in 2010 by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 7 μb−1. The vm−vn correlations are measured in midrapidity as a function of centrality, and, for events within the same centrality interval, as a function of event ellipticity or triangularity defined in a forward rapidity region. For events within the same centrality interval, v3 is found to be anticorrelated with v2 and this anticorrelation is consistent with similar anticorrelations between the corresponding eccentricities, ε2 and ε3. However, it is observed that v4 increases strongly with v2, and v5 increases strongly with both v2 and v3. The trend and strength of the vm−vn correlations for n=4 and 5 are found to disagree with εm−εn correlations predicted by initial-geometry models. Instead, these correlations are found to be consistent with the combined effects of a linear contribution to vn and a nonlinear term that is a function of v22 or of v2v3, as predicted by hydrodynamic models. A simple two-component fit is used to separate these two contributions. The extracted linear and nonlinear contributions to v4 and v5 are found to be consistent with previously measured event-plane correlations

Search for W′→tb→qqbb decays in pp collisions at √s=8 TeV with the ATLAS detector

A search for a massive W′ gauge boson decaying to a top quark and a bottom quark is performed with the ATLAS detector in pp collisions at the LHC. The dataset was taken at a centre-of-mass energy of √s=8 TeV and corresponds to 20.3 fb−1 of integrated luminosity. This analysis is done in the hadronic decay mode of the top quark, where novel jet substructure techniques are used to identify jets from high-momentum top quarks. This allows for a search for high-mass W′ bosons in the range 1.5–3.0 TeV. b-tagging is used to identify jets originating from b-quarks. The data are consistent with Standard Model background-only expectations, and upper limits at 95 % confidence level are set on the W′→tb cross section times branching ratio ranging from 0.16pb to 0.33pb for left-handed W′ bosons, and ranging from 0.10pb to 0.21pb for W′ bosons with purely right-handed couplings. Upper limits at 95 % confidence level are set on the W′-boson coupling to tb as a function of the W′ mass using an effective field theory approach, which is independent of details of particular models predicting a W′boson

Sorogrupos e genes de virulência em Escherichia coli isoladas de psitacídeos

Escherichia coli isolates from 24 sick psittacine birds were serogrouped and investigated for the presence of genes encoding the following virulence factors: attaching and effacing (eae), enteropathogenic E. coli EAF plasmid (EAF), pili associated with pyelonephritis (pap), S fimbriae (sfa), afimbrial adhesin (afa), capsule K1 (neu), curli (crl, csgA), temperature-sensitive hemagglutinin (tsh), enteroaggregative heat-stable enterotoxin-1 (astA), heat-stable enterotoxin -1 heat labile (LT) and heat stable (STa and STb) enterotoxins, Shiga-like toxins (stx1 and stx2), cytotoxic necrotizing factor 1 (cnf1), haemolysin (hly), aerobactin production (iuc) and serum resistance (iss). The results showed that the isolates belonged to 12 serogroups: O7; O15; O21; O23; O54; O64; O76; O84; O88; O128; O152 and O166. The virulence genes found were: crl in all isolates, pap in 10 isolates, iss in seven isolates, csgA in five isolates, iuc and tsh in three isolates and eae in two isolates. The combination of virulence genes revealed 11 different genotypic patterns. All strains were negative for genes encoding for EAF, EAEC, K1, sfa, afa, hly, cnf, LT, STa, STb, stx1 and stx2. Our findings showed that some E. coli isolated from psittacine birds present the same virulence factors as avian pathogenic E. coli (APEC), uropathogenic E. coli (UPEC) and Enteropathogenic E. coli (EPEC) pathotypes.Amostras de Escherichia coli isoladas de 24 psitacídeos doentes foram sorogrupadas e investigadas para a presença de genes que codificam os seguintes fatores de virulência: attaching e effacing (eae), plasmídeo EAF (EAF), pili associado à pielonefrite (pap), fímbria S (sfa), adesina afimbrial (afa), cápsula K1 (neu), curli (crl, csgA), hemaglutinina termosensível (tsh), enterotoxina termo-estável 1 de E. coli enteroagregativa (astA), toxina termolábil (LT) e toxina termoestável (STa e STb), Shiga-like toxinas (stx1 e stx2), fator citotóxico necrotizante 1 (cnf1), hemolisina (hly), produção de aerobactina (iuc) e resistência sérica (iss). Os resultados mostraram que os isolados pertenciam a 12 sorogrupos: O7; O15; O21; O23; O54; O64; O76; O84; O88; O128; O152 e O166. Os genes de virulência encontrados foram: crl em todos os isolados, pap em 10 isolados, iss em sete isolados, csgA em cinco isolados, iuc e tsh em três isolados e eae em dois isolados. A combinação dos genes de virulência revelou 11 perfis genotípicos distintos. Todas as amostras foram negativas para os genes que codificam EAF, EAEC, K1, sfa, afa, hly, cnf, LT, STa, STb, stx1 e stx2. Estes resultados demonstraram que algumas amostras de E. coli isoladas de psitacídeos apresentam os mesmos fatores de virulência presentes nos patotipos de E. coli patogênicas para aves (APEC), uropatogênicas (UPEC) e E. coli enteropatogênicas (EPEC).916921Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP