A new way to construct 1-singular Gelfand-Tsetlin modules

We present a simplified way to construct the Gelfand-Tsetlin modules over $\mathfrak{gl}(n,\mathbb C)$ related to a $1$-singular GT-tableau defined by Futorny, Grantcharov and Ramirez. We begin by reframing the classical construction of generic Gelfand-Tsetlin modules found by Drozd, Futorny and Ovsienki, showing that they form a flat family over generic points of $\mathbb C^{\binom{n}{2}}$. We then show that this family can be extended to a flat family over a variety including generic points and $1$-singular points for a fixed singular pair of entries. The $1$-singular modules are precisely the fibers over these points.Comment: 12 pages. Sent for publication in Algebra and Discrete Mathematic

Atmospheric drag on artificial satellites

By using observed values of dP/dt and a convenient model to represent the variable density (ρ) and the scale height (H) of the atmosphere, we calculate mean values for the effective cross-section (S) of a non-spherical satellite at every day during a period of about two and half months. For that calculation we assume in advance that the satellite tumbles around an axis perpendicular to thè longest axis of symmetry. For Satellite 1958 Epsilon (Explorer IV) the orientation of the axis of rotation has been determinated by an analysis of the variation in intensity of the measured radio-transmission from the satellite (Nau- mann,196l). A similar analysis has been carried out for the rocket of Sputnik III (Satellite 1958 δ1) based on its variations of visual brightness (Notni and 01eak,1959). Our results on the effective drag area show a good agreement with those obtained from both analysis. (Párrafo extraído a modo de resumen)Asociación Argentina de Astronomí

Atmospheric drag on artificial satellites

By using observed values of dP/dt and a convenient model to represent the variable density (ρ) and the scale height (H) of the atmosphere, we calculate mean values for the effective cross-section (S) of a non-spherical satellite at every day during a period of about two and half months. For that calculation we assume in advance that the satellite tumbles around an axis perpendicular to thè longest axis of symmetry. For Satellite 1958 Epsilon (Explorer IV) the orientation of the axis of rotation has been determinated by an analysis of the variation in intensity of the measured radio-transmission from the satellite (Nau- mann,196l). A similar analysis has been carried out for the rocket of Sputnik III (Satellite 1958 δ1) based on its variations of visual brightness (Notni and 01eak,1959). Our results on the effective drag area show a good agreement with those obtained from both analysis. (Párrafo extraído a modo de resumen)Asociación Argentina de Astronomí

Atmospheric drag on artificial satellites

By using observed values of dP/dt and a convenient model to represent the variable density (ρ) and the scale height (H) of the atmosphere, we calculate mean values for the effective cross-section (S) of a non-spherical satellite at every day during a period of about two and half months. For that calculation we assume in advance that the satellite tumbles around an axis perpendicular to thè longest axis of symmetry. For Satellite 1958 Epsilon (Explorer IV) the orientation of the axis of rotation has been determinated by an analysis of the variation in intensity of the measured radio-transmission from the satellite (Nau- mann,196l). A similar analysis has been carried out for the rocket of Sputnik III (Satellite 1958 δ1) based on its variations of visual brightness (Notni and 01eak,1959). Our results on the effective drag area show a good agreement with those obtained from both analysis. (Párrafo extraído a modo de resumen)Asociación Argentina de Astronomí