Atmospheric Heating and Wind Acceleration: Results for Cool Evolved Stars based on Proposed Processes

A chromosphere is a universal attribute of stars of spectral type later than ~F5. Evolved (K and M) giants and supergiants (including the zeta Aurigae binaries) show extended and highly turbulent chromospheres, which develop into slow massive winds. The associated continuous mass loss has a significant impact on stellar evolution, and thence on the chemical evolution of galaxies. Yet despite the fundamental importance of those winds in astrophysics, the question of their origin(s) remains unsolved. What sources heat a chromosphere? What is the role of the chromosphere in the formation of stellar winds? This chapter provides a review of the observational requirements and theoretical approaches for modeling chromospheric heating and the acceleration of winds in single cool, evolved stars and in eclipsing binary stars, including physical models that have recently been proposed. It describes the successes that have been achieved so far by invoking acoustic and MHD waves to provide a physical description of plasma heating and wind acceleration, and discusses the challenges that still remain.Comment: 46 pages, 9 figures, 1 table; modified and unedited manuscript; accepted version to appear in: Giants of Eclipse, eds. E. Griffin and T. Ake (Berlin: Springer

Autonomic nervous system dysfunction in children with severe tetanus: dissociation of cardiac and vascular sympathetic control

The medical records of ten pediatric patients with a clinical diagnosis of tetanus were reviewed retrospectively. The heart rate and blood pressure of all tetanus patients were measured noninvasively every hour during the first two weeks of hospitalization. Six of ten tetanus patients presented clinical evidence of sympathetic hyperactivity (group A) and were compared with a control group consisting of four children who required mechanical ventilation for diseases other than tetanus (group B). Heart rate and blood pressure simultaneously and progressively increased to a maximum by day 7. The increase over baseline was 43.70 ± 11.77 bpm (mean ± SD) for heart rate (P<0.01) and 38.60 ± 26.40 mmHg for blood pressure (P<0.01). These values were higher and significantly different from those of the control group (group B) at day 6, which had an average heart rate increase over baseline of 19.35 ± 12.26 bpm (P<0.05) and blood pressure of 10.24 ± 13.30 mmHg (P<0.05). By the end of the second week of hospitalization, in group A the increase of systolic blood pressure over baseline had diminished to 9.60 ± 15.37 mmHg (P<0.05), but the heart rate continued to be elevated (27.80 ± 33.92 bpm, P = NS), when compared to day 7 maximal values. The dissociation of these two cardiovascular variables at the end of the second week of hospitalization suggests the presence of asymmetric cardiac and vascular sympathetic control. One possible explanation for these observations is a selective and delayed action of tetanus toxin on the inhibitory neurons which control sympathetic outflow to the heart

Model Solutions (cmc-sucrose) Stability Evaluation After Several Freezing Process [avaliação Da Estabilidade De Soluções Modelo (cmc-sacarose) Em Recongelamentos]

The objective of this paper was to evaluate the stability of the model solutions determining initial freezing temperature after repeated freezing process. The solutions were composed by water, sucrose and Carboxymethylcellulose (CMC). Were evaluated the concentrations of sucrose from 15% to 31.1% (w/w) and the concentration of CMC from 0.5%, 1.0% to 1.5% (w/w). It was also studied the possibility of reutilization of the model solutions for freezing tests. The results showed that at the concentration of 0.5% there was no alteration at the water binding capacity. The variation of sucrose concentration did not interfered in the stability of the solution during the study.281125132Becker, B.R., Fricke, B.A., Food thermophysical property models (1999) Int. Comm. Heat and Mass Transfer, 26 (5), pp. 627-636Berto, M.I., Gratão, A.C.A., Silveira Jr., V., Vitali, A.A., Solução modelo de sacarose e CMC: Análise do tempo de hidratação, caracterização reológica e estabilidade térmica (2003) Brazilian J. Food Techn, 6 (107), pp. 9-14Fellows, P.J., (2000) Food Processing Technology: Principles and Practice, p. 575. , Cambridge, UK: Woodhead PublishingFikiin, K.A., Fikiin, A.G., Predictive equations for thermophysical properties and enthalpy during cooling and freezing of food materials (1999) J. Food Eng, 40, pp. 1-6Fennema, O.R., Powri, W.D., Marth, E.H., (1973) Low Temperature Preservation of Foods and Living Matter, , New York: Marcel DeckerHolland, B., Welch, A.A., Unwin, I.D., Buss, D.H., Paul, A.A., Southgate, D.A.T., (1991) McCance & Widdowson's: The Composition of Foods, p. 554. , 5th ed. Cambridge, UK: Royal Society of ChemistryJeremiah, L.E., (1996) Freezing Effcts On Food Quality, p. 520. , New York: Marcel DekkerPongsawatmanit, R., Miyawaki, O., Measurement of temperature-dependent ice fraction in frozen foods (1993) Bioscience, Biotechnology and Biochemistry, 57 (10), pp. 1650-1654Renaud, T., Thermal properties of model foods in the frozen state (1992) J. Food Eng, 15, pp. 83-97Resende, J.V., Neves, F.L.C., Silveira Jr., V., Coeficientes de transferência de calor efetivos no congelamento com ar forçado de modelos de polpas de frutas em caixas comerciais (2002) Brazilian J. Food Techn, 5, pp. 33-42Resende, J.V., Silveira Jr., V., Medidas da condutividade térmica efetiva em modelos de polpas de frutas no estado congelado (2002) Ciência E Tecnologia De Alimentos, 22 (2), pp. 177-183Resende, J.V., Silveira Jr., V., Escoamento de ar através de embalagens de polpa de frutas em caixas comerciais: Efeitos sobre os perfis de velocidade em túneis de congelamento (2002) Ciência E Tecnologia De Alimentos, 22 (2), pp. 184-191Saad, Z., Scott, E.P., Estimation of temperature dependent thermal properties of basic food solutions during freezing (1996) J. Food Eng, 28, pp. 1-19Scott, E.P., Beck, J.V., Heldman, D.R., Estimation of time variable heat transfer coefficients in frozen foods during storage (1992) J. Food Eng, 15, pp. 99-121(2008) Agriculture Research Service, p. 49. , USDA. United States Department of Agriculture, USDA National Nutrient Database for Standard Reference. Composition of foods raw, processed, prepared. Release 21. Beltsville, MarylandZaritzki, N.E., Factors affecting the stability of frozen foods (2000) Managing Frozend Foods, , In: KENNEDY, C.J, Cambridge: Wood head Publishin