Vinculación física entre super cáscaras de hidrógeno neutro y formación estelar reciente

Las super cáscaras de Hi (SCHi) podrían haber sido formadas por vientos estelares y/o explosiones de supernovas. Con tiempos dinámicos de vida del orden de decenas de millones de años, las estructuras de mayor tamaño sobreviven a las estrellas de gran masa que pudieran haberle dado origen. Por este motivo, las SCHi podrían ser usadas como registros fósiles para estudiar los efectos de formación estelar en la Vía Láctea. Por otra parte, durante su evolución, las SCHi podrían dar origen a nuevas generaciones de estrellas. En este trabajo investigamos la posible vinculación física entre la asociación OB Centaurus OB1 y la SCHi GSH305+01-24 del catálogo de McClure-Griffiths et al. (2002). De nuestro estudio concluimos que GSH305+01-24 no representa una estructura física real. Su estructura resulta mejor representada por dos grandes cáscaras no vinculadas entre sí. En este contexto, no resulta claro el rol que pueda haber jugado Cen OB1 en la creación de una de estas cáscaras de Hi.Many of the known galactic Hi supershells may have been formed by the combined effects of stellar winds and supernovae explosions. Having most of them dynamic lifetimes of a few times 107 yr, these huge structures are likely to outlive the stars that gave rise to them. Hence, these galactic Hi supershells may be used as fossil records of the Milky Way star formation history. Furthermore, along their evolution galactic Hi supershells may trigger star formation. In this paper we analyze the genetic link put forward by McClure-Griffiths et al. (2002) between the OB association Cen OB1 and the galactic Hi supershells GSH305+01-24. From own study we conclude that GSH305+01-24 may not represent a real physical structure. Instead, we believe that their structure is best represented by two unrelated huge Hi shells. The role played by Cen OB1 in powering one of these Hi shells is unclear for the time beeing.Fil: Corti, Mariela Alejandra. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomia; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Arnal, Edmundo Marcelo. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomia; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentin

The new HI supershell GS263-02+45 and the OB Association Bochum 7: close relatives?

Neutral hydrogen (HI) supershells are usually identified, in a given velocity range, as a brightness temperature minimum in the HI distribution that is surrounded by walls of HI emission. McClure-Griffiths et al. (2002) reported the discovery of GSH263+00+47, centered at (l,b) = (263°.0, 0°.0). The OB association Bochum 7 (l,b) = (265°.0, -2°.0) is seen in projection onto the outer border of GSH263+00+47.Instituto de Astrofísica de La PlataInstituto Argentino de Radioastronomí

The new HI supershell GS263-02+45 and the OB Association Bochum 7: close relatives?

Neutral hydrogen (HI) supershells are usually identified, in a given velocity range, as a brightness temperature minimum in the HI distribution that is surrounded by walls of HI emission. McClure-Griffiths et al. (2002) reported the discovery of GSH263+00+47, centered at (l,b) = (263°.0, 0°.0). The OB association Bochum 7 (l,b) = (265°.0, -2°.0) is seen in projection onto the outer border of GSH263+00+47.Instituto de Astrofísica de La PlataInstituto Argentino de Radioastronomí

GS263-02+45: A new HI supershell with evidence of having triggered star formation?

Aims.We look for galactic neutral hydrogen (Hi) supershells likely to be associated with massive star groupings.Methods.A neutral hydrogen (Hi) line survey carried out at the Instituto Argentino de Radioastronomía (IAR) and the Southern Galactic Plane Survey (SGPS) were the main databases used in this investigation.Results.A new Hi supershell (GS263-02+45) was found in the outer part of the Galaxy. This structure is located at a distance of 5.3 1 kpc from the Sun and has a linear diameter of about 665 40 pc. The expansion velocity of the supershell is ~14 km s. The total amount of atomic gas related to GS263-02+45 is ~2 10 . Based on the analysis of the SGPS Hi data it is concluded that the OB-association Bochum 7 is likely to be interacting with GS263-02+45. This fact together with distance and age arguments may indicate that Bochum 7 was born as a consequence of the evolution of GS263-02+45.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

Los aportes de Jordi Borja al pensamiento y la acción urbanística

El presente trabajo ofrece una síntesis de los principales ejes de reflexión del aporte urbanístico de Jordi Borja. Tanto en sus propuestas como en sus rechazos Borja procura dar respuesta a las preguntas y desafíos del momento histórico. Esta elección le ha deparado críticas, pero no lo ha apartado de su compromiso personal con la “ciudad democrática”. En esa línea, la evolución de su pensamiento se corresponde más con variaciones tácticas acordes a los giros de la historia y a su propio rol como intelectual militante que con un cambio estratégico en la manera de entender las ciudades como escenario, objeto y –sobre todo– sujeto de transformación social y política. Los ejes de reflexión sobre los que se sustenta el aporte de Borja pueden enunciarse sintéticamente: a. los movimientos sociales y vecinales como motor de cambio político, b. el espacio público como condición de ciudadanía, c. el enfoque de derechos como sustento de la actuación urbanística, d. la ciudad como sujeto político y espacio de libertad frente a los poderes del Estado conservador –un sujeto político articulador de lo global y lo local; y e. la tensión entre institucionalidad y demanda de cambio

Plan de gestión de residuos sólidos urbanos en la Facultad de Ciencias Económicas (UBA): ECON VERDE, el camino hacia la gestión integral (Período 2016 / 2018)

Fil: Corti, Marcelo A.. Universidad de Buenos Aires. Facultad de Ciencias Económicas. Buenos Aires, Argentina

GS305+04-26: Revisiting the interstellar medium around the Centaurus OB1 stellar association

Context. Massive stars deeply modify their surrounding interstellar medium (ISM) via their high throughput of ionizing photons and their strong stellar winds. In this way, they may create large expanding structures of neutral gas. Aims. We study a new large neutral hydrogen (Hi) shell, labelled GS305+04-26, and its relationship with the OB association Cen OB1. Methods. To carry out this study, we have used a multi-wavelength approach. We analyse both Hi line data retrieved from the Leiden-Argentina-Bonn (LAB) survey and new spectroscopic optical observations obtained at CASLEO, as well as make use of proper motion databases available from CDS. Results. The analysis of the Hi data reveals a large expanding structure GS305+04-26 centred at (l,b) = (305°, + 4°) in the velocity range from-33 to-17 km s -1. Based on its central velocity of-26 km s -1 and using standard galactic rotation models, a distance of 2.5 ± 0.9 kpc is inferred. This structure, elliptical in shape, has a major and minor axis of 440 and 270 pc, respectively. Its expansion velocity, total gaseous mass, and kinetic energy are ~8 km s -1, (2.4 ± 0.5) × 10 5 M âŠ(tm), and (1.6 ± 0.4) × 10 50 erg, respectively. Several stars of the OB-association Cen OB1 are seen projected onto, and within, the boundaries of GS305+04-26. Based on an analysis of proper motions, new members of Cen OB1 are identified. The mechanical energy injected by these stars could have been the origin of this Hi structure.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

Carcinoma de células escamosas do canal anal: a nova neoplasia associada com AIDS?

O carcinoma de células escamosas do canal anal é uma malignidade rara que representa 1,5% a 2% de todos os cânceres do trato gastrointestinal inferior. Entretanto, é observada uma incidência aumentada do carcinoma anal invasivo, na população soropositiva para o HIV desde a difusão da terapia antirretroviral altamente ativa. O vírus do papiloma está fortemente associado com a patogênese do câncer anal. Sexo anal e um alto número de parceiros sexuais parecem ser os fatores de risco para desenvolver câncer anal em ambos os sexos. Dor anal, sangramento e lesão palpável no canal anal são as manifestações clínicas mais comuns. O ultrassom endoanal é o melhor método diagnóstico para avaliar o tamanho do tumor, sua extensão e a infiltração para o complexo do músculo esfincteriano. A quimioradioterapia mais terapia antirretroviral é o tratamento recomendado para todos os estádios do carcinoma localizado de células escamosas do canal anal nos pacientes HIV soropositivos, devido a sua alta taxa de cura. Apresentamos um paciente que desenvolveu carcinoma do canal anal depois de um longo tempo de infecção por HIV sob tratamento com a terapia antirretroviral altamente ativa, com boa resposta virológica e imunológica.Squamous anal cell carcinoma is a rare malignancy that represents the 1.5% to 2% of all the lower digestive tract cancers. However, an increased incidence of invasive anal carcinoma is observed in HIV-seropositive population since the widespread of highly active antiretroviral therapy. Human papillomavirus is strongly associated with the pathogenesis of anal cancer. Anal intercourse and a high number of sexual partners appear to be risk factors to develop anal cancer in both sexes. Anal pain, bleeding and a palpable lesion in the anal canal are the most common clinical features. Endo-anal ultrasound is the best diagnosis method to evaluate the tumor size, the tumor extension and the infiltration of the sphincter muscle complex. Chemoradiotherapy plus antiretroviral therapy are the recommended treatments for all stages of localized squamous cell carcinoma of the anal canal in HIV-seropositive patients because of its high rate of cure. Here we present an HIV patient who developed a carcinoma of the anal canal after a long time of HIV infection under highly active antiretroviral therapy with a good virological and immunological response

Disseminated paracoccidioidomycosis with peripleuritis in an AIDS patient

La paracoccidioidomicosis es una de las micosis sistémicas endémicas más frecuentes de Latinoamérica, causada por un hongo dimorfo. En los pacientes con SIDA se presenta como una enfermedad grave y diseminada, con un amplio espectro de manifestaciones clínicas. Los niveles de linfocitos T CD4 + son habitualmente < de 200 cél/myL. Presentamos un caso de paracoccidioidomicosis diseminada con peripleuritis y abscesos subcutáneos sobre la pared torácica como manifestación inicial del SIDA. En países endémicos, la paracoccidioidomicosis debe incluirse como una complicación oportunista de los pacientes con SIDA.Paracoccidioidomycosis is one of the most frequent systemic and endemic mycoses of Latin America caused by a dimorphic fungus. In AIDS patients, paracoccidioidomycosis appears as a severe and disseminated disease with a wide spectrum of clinical findings. The CD4 counts are usually less than 200 cell/mu L. We present a case of disseminated paracoccidioidomycosis with peripleuritis and subcutaneous abscesses on the chest wall as initial manifestation of AIDS. In endemic countries, paracoccidioidomycosis should be included as an opportunistic infection in AIDS