Some comments on the F ring-Prometheus-Pandora environment

The system formed by the F ring and two close satellites, Prometheus and Pandora, has been analysed since the time that Voyager visited the planet Saturn. During the ring plane crossing in 1995 the satellites were found in different positions as predicted by the Voyager data. Besides the mutual effects of Prometheus and Pandora, they are also disturbed by a massive F ring. Showalter et al. [Icarus 100 (1992) 394] proposed that, the core of the ring has a mass which corresponds to a moonlet varying in size from 15 to 70 kin in radius which can prevent the ring from spreading due to dissipative forces, such as Poynting-Robertson drag and collisions. We have divided this work into two parts. Firstly we analysed the secular interactions between Prometheus-Pandora and a massive F ring using the secular theory. Our results show the variation in eccentricity and inclination of the satellites and the F ring taking into account a massive ring corresponding to a moonlet of different sizes. There is also a population of dust particles in the ring in the company of moonlets at different sizes [Icarus 109 (1997) 304]. We also analysed the behaviour of these particles under the effects of the Poynting-Robertson drag and radiation pressure. Our results show that the time scale proposed for a dust particle to leave the ring is much shorter than predicted before even in the presence of a coorbital moonlet. This result does not agree with the confinement model proposed by Dermott et al. [Nature 284 (1980) 309]. In 2004, Cassini mission will perform repeated observations of the whole system, including observations of the satellites and the F ring environment. These data will help us to better understand this system. (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

TERRESTRIAL PLANET FORMATION IN A PROTOPLANETARY DISK WITH A LOCAL MASS DEPLETION: A SUCCESSFUL SCENARIO FOR THE FORMATION OF MARS

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Katherine A. Kendall (USA), Honorary President since 1978

For more than two-thirds of the life of the International Association of Schools of Social Work (IASSW), Katherine Kendall has been among its leaders. She began her involvement in 1950, served as the first paid Secretary General of the Association in the 1970's and, now in her late 90's, continues to share her wisdom as Honorary President. Beginning in 1950, she attended all the IASSW congresses except 2 (1990 and 1998) until 2004, when health issues prevented long international trips. She personally knew and worked with every President except the first. Thus, although the IASSW began with sustained involvement and contributions of two remarkable founders, Alice Salomon and René Sand, Kendall has surpassed all in terms of her enduring commitment to international social work education and its professional organization. Kendall's remarkable professional career spans 7 decades. Her international involvements began even earlier.

Katherine A. Kendall (USA), Honorary President since 1978

For more than two-thirds of the life of the International Association of Schools of Social Work (IASSW), Katherine Kendall has been among its leaders. She began her involvement in 1950, served as the first paid Secretary General of the Association in the 1970's and, now in her late 90's, continues to share her wisdom as Honorary President. Beginning in 1950, she attended all the IASSW congresses except 2 (1990 and 1998) until 2004, when health issues prevented long international trips. She personally knew and worked with every President except the first. Thus, although the IASSW began with sustained involvement and contributions of two remarkable founders, Alice Salomon and René Sand, Kendall has surpassed all in terms of her enduring commitment to international social work education and its professional organization. Kendall's remarkable professional career spans 7 decades. Her international involvements began even earlier. This article will focus on highlights of her international career, especially her IASSW service. It will also discuss her formative years and mention other aspects of contributions. Materials for the article are drawn from published and unpublished interviews conducted by other scholars, Kendall's own writings, and a personal interview conducted by the author in 2007.

Potential economic impacts of changes in Puerto Rico's status under S. 712.

"April 1990."

Gender, genre and the (re)invention of life in Charlotte Salomon's Life? or Theatre?

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Aggregates in the strength and gravity regime: Particles sizes in Saturn's rings

Particles in Saturn's main rings range in size from dust to kilometer-sized objects. Their size distribution is thought to be a result of competing accretion and fragmentation processes. While growth is naturally limited in tidal environments, frequent collisions among these objects may contribute to both accretion and fragmentation. As ring particles are primarily made of water ice attractive surface forces like adhesion could significantly influence these processes, finally determining the resulting size distribution. Here, we derive analytic expressions for the specific self-energy Q and related specific break-up energy Q(star) of aggregates. These expressions can be used for any aggregate type composed of monomeric constituents. We compare these expressions to numerical experiments where we create aggregates of various types including: regular packings like the face-centered cubic (fcc), Ballistic Particle Cluster Aggregates (BPCA), and modified BPCAs including e.g. different constituent size distributions. We show that accounting for attractive surface forces such as adhesion a simple approach is able to: (a) generally account for the size dependence of the specific break-up energy for fragmentation to occur reported in the literature, namely the division into "strength" and "gravity" regimes and (b) estimate the maximum aggregate size in a collisional ensemble to be on the order of a few tens of meters, consistent with the maximum particle size observed in Saturn's rings of about 10 m. (c) 2012 Elsevier B.V. All rights reserved.

Familientafel des Rabbiners Dr. Salomon Cohn sel. And.

[Verf.[[Elektronische Ressource]] : Alfred Cohn]

Status of the Mariner Jupiter/Saturn 1977 project : National Aeronautics and Space Administration : report to the Congress /

"B-183134."

Study of interplanetary missions to Mercury through Saturn with emphasis on manned missions to Venus and Mars 1973/82 involving capture.

At head of title: GD/A 63-0916.