Magnetism, rotation and accretion in Herbig Ae-Be stars

Studies of stellar magnetism at the pre-main sequence phase can provide important new insights into the detailed physics of the late stages of star formation, and into the observed properties of main sequence stars. This is especially true at intermediate stellar masses, where magnetic fields are strong and globally organised, and therefore most amenable to direct study. This talk reviews recent high-precision ESPaDOnS observations of pre-main sequence Herbig Ae-Be stars, which are yielding qualitatively new information about intermediate-mass stars: the origin and evolution of their magnetic fields, the role of magnetic fields in generating their spectroscopic activity and in mediating accretion in their late formative stages, and the factors influencing their rotational angular momentum.Comment: 8 page

Spectroscopic monitoring of the Herbig Ae star HD 104237. II. Non-radial pulsations, mode analysis and fundamental stellar parameters

Herbig Ae/Be stars are intermediate-mass pre-main sequence (PMS) stars showing signs of intense activity and strong stellar winds, whose origin is not yet understood in the frame of current theoretical models of stellar evolution for young stars. The evolutionary tracks of the earlier Herbig Ae stars cross a recently discovered PMS instability strip. Many of these stars exhibit pulsations of delta Scuti type. HD 104237 is a well-known pulsating Herbig Ae star. In this article, we reinvestigated an extensive high-resolution quasi-continuous spectroscopic data set in order to search for very faint indications of non-radial pulsations in the line profile. To do this, we worked on dynamical spectra of equivalent photospheric (LSD) profiles of HD 104237. A 2D Fourier analysis (F2D) was performed of the entire profile and the temporal variation of the central depth of the line was studied with the time-series analysis tools Period04 and SigSpec. We present a mode identification corresponding to the detected dominant frequency. We perform a new accurate determination of the fundamental stellar parameters in view of a forthcoming asteroseismic modeling. Following the previous studies on this star, our analysis of the dynamical spectrum of recentered LSD profiles corresponding to the 22nd -25th of April 1999 nights spectra has confirmed the presence of multiple oscillation modes of low-degree l in HD 104237 and led to the first direct detection of a non-radial pulsation mode in this star: the dominant mode F1 was identified by the Fourier 2D method having a degree l value comprised between 1 and 2, the symmetry of the pattern variation indicating an azimuthal order of +1 or -1. The detailed study of the fundamental stellar parameters has provided a Teff, log g and iron abundance of 8550 +/- 150K, 3.9 +/- 0.3 and -4.38 +/- 0.19 (i.e. [Fe/H]=+0.16 +/- 0.19), respectively

Charged-Current Neutral Pion production at SciBooNE

SciBooNE, located in the Booster Neutrino Beam at Fermilab, collected data from June 2007 to August 2008 to accurately measure muon neutrino and anti-neutrino cross sections on carbon below 1 GeV neutrino energy. SciBooNE is studying charged current interactions. Among them, neutral pion production interactions will be the focus of this poster. The experimental signature of neutrino-induced neutral pion production is constituted by two electromagnetic cascades initiated by the conversion of the neutral pion decay photons, with an additional muon in the final state for CC processes. In this poster, I will present how we reconstruct and select charged-current muon neutrino interactions producing neutral pions in SciBooNE.Comment: NuInt09 poster proceedings, 4 page

Introductory Chapter: Endoplasmic Reticulum-Knowledge and Perspectives

The endoplasmic reticulum is one of the most studied and fascinating organelles. It is found in all eukaryotic cells and performs a variety of functions. The organelle was designated by this name by Keith Porter in 1953 on the basis of studies carried out with the electron microscope in cells in tissue culture. Porter was able to differentiate the exoplasm, an adjacent region devoid of organelles, from the neighboring endoplasm. In the endoplasm, he examined a system of interrelated tubules, a reticulum, for this reason, the name “endoplasmic reticulum” (ER). The collaboration between Keith Porter and George Palade showed that ER exists in all eukaryotic cells and that it consists of different but continuous domains, the smooth and rough ER, whose abundance fluctuates between different types of cells. Palade observed on the surface of the rough ER the ribosomes that synthesized secretory proteins. The secretory proteins would cross an intracellular membrane, instead of the plasma membrane. The verification of this concept led to the discovery of the secretion pathway and the conception of intracellular protein binding to various organelles.Fil: Catala, Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentin

Comparative seismology of pre- and main sequence stars in the instability strip

Pulsational properties of 1.8 M$_{\odot}$ stellar models covering the latest stages of contraction toward the main sequence up to early hydrogen burning phases are investigated by means of linear nonadiabatic analyses. Results confirm that pre-main sequence stars (pms) which cross the classical instability strip on their way toward the main sequence are pulsationally unstable with respect to the classical opacity mechanisms. For both pms and main sequence types of models in the lower part of the instability strip, the unstable frequency range is found to be roughly the same. Some non-radial unstable modes are very sensitive to the deep internal structure of the star. It is shown that discrimination between pms and main sequence stages is possible using differences in their oscillation frequency distributions in the low frequency range.Comment: 8 pages, 9 figures, accepted for publication in A&

Influye la alimentación sobre el dimorfismo sexual en Triatoma infestans (Hemiptera, Reduviidae) de hábitats naturales?

Triatoma infestans es el principal vector del parásito que causa la enfermedadde Chagas en Sudamérica. Se sabe que T. infestans tiene diferentes patrones reproductivosy de desarrollo dependiendo de si se alimentan de aves o mamíferos. Utilizando la cabeza deinsectos adultos como estimador del desarrollo, se intenta determinar si existen diferenciasen el dimorfismo de tamaño sexual asociado con la disponibilidad del recurso alimenticioen T. infestans de hábitats naturales en la región de Llanos Riojanos (Argentina). El estadonutricional fue mayor en gallineros y, en ambos hábitats, fue mayor para las hembrasen relación con los machos. El tamaño centroide fue mayor en las hembras que en losmachos de gallineros, pero no en los especímenes de corrales de cabras. Los tamañoscentroide revelaron medianas más pequeñas en insectos de cabra en comparación con losprocedentes de gallineros. El dimorfismo sexual del tamaño se asocia con diferencias en elestado nutricional solo para triatominos de gallineros de habitats naturales. La conformaciónde las cabezas no se vio influenciada por el estado nutricional. Las diferenciasmorfofisiológicas encontradas en T. infestans ayudan a comprender aspectos delcomportamiento de la especie en diversos ambientes y sus implicaciones en la transmisiónvectorial de Trypanosoma cruzi.Triatoma infestans is the main vector of the parasite that causes the Chagas disease in South America. It is known that T. infestans has different reproductive and development patterns depending on whether they feed on birds or mammals. Using the head of adult insects as an estimator of the specimen development, we attempt to determine if there are any differences in the sexual size dimorphism associated with the availability of the food resource in T. infestans of natural habitats in the Llanos Riojanos region (Argentina). The nutritional status resulted higher in chicken coops and, in both habitats, it was higher for females in relation to males. The centroid size was larger in females than in males from chicken coops, but not in the specimens from goat corrals. Centroid sizes revealed smaller medians in goat insects in comparison to those coming from chicken coops. Sexual size dimorphism occurs associated with differences in the nutritional status only for triatomines from chicken coops in natural habitats. The heads shape was not influenced by the nutritional status. The sexual morphophysiological differences found in T. infestans help us understand aspects of the behavior of the species in diverse environments and its implications in the vectorial transmission of Trypanosoma cruzi.Fil: Hernández, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; ArgentinaFil: Amelotti, Ivana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; Argentina. Universidad Nacional de La Rioja; ArgentinaFil: Catala, Silvia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; ArgentinaFil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Actividades Espaciales; Argentin

Introductory Chapter: Liposomes - Advances and Perspectives - My Point of View

Liposomes are vesicular arrangements composed of one or more phospholipid bilayers surrounding an aqueous core. Liposomes were discovered almost six decades ago. Due to its versatility, liposomes are now analyzed for their applicability both in laboratory techniques and in medical studies. Its interest lies in its ability to traverse cell membranes and to transport certain types of molecules to defined places in the human body. Liposomes can carry both hydrophilic and hydrophobic molecules. The preparation of the liposomes results in different properties for these systems. There are several factors involved in the preparation of liposomes that can modify their structures. Due to its biological compatibility, nonimmunogenicity, greater solubility of chemotherapeutic agents, and its ability to encapsulate a wide variety of drugs, the supply of drugs using liposomes has meant a great advance. The purpose of this book is to focus on recent developments in liposomes. The chapters selected in this book are contributions from invited researchers with long experience in different areas of research. This book offers expert and updated reviews of the field of liposomes.Fil: Catala, Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentin