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This licentiate thesis presents our investigation of Saturn's inner plasma disk. The thesis gives an overview of the Cassini-Huygens project, what a plasma is and how we use the Langmuir probe to investigate it, various difficulties related to the measurements, the structure of the magnetosphere of Saturn, with special focus on the inner magnetosphere and the region around the Saturnian moon Enceladus. For our investigation we use the Cassini Langmuir probe to derive ion density and ion velocity in the region from 2.5 to 12 Saturn radii. We show that the dominant part of the plasma torus, ion density above ~15 particle/cm3, is located in between 2.5 and 8 Saturn radii (1 RS = 60,268 km) from the planet, with a north-southward extension of <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5Cpm" />2 RS. The plume of the moon Enceladus is clearly visible as an ion density maximum of 105 cm-3, only present at the south side of the ring plane, as expected since the Enceladus plumes are located in the south polar region. Also the azimuthal ion velocity vi,Θ is estimated, showing a clear general trend in the region between 3 and 7 RS, described by vi,Θ =1.5R2-8.7R+39. The average vi,Θ starts to deviate from corotation speed at around 3 RS and reaches down to ~68 % of corotation close to 5 RS. The Langmuir probe data show a clear day/night side asymmetry in both ion density and ion velocity, most prominent in the radial region 4-6 RS from the center of Saturn. The ion densities ni varies from an average of ~35 cm-3 for the lowest dayside values close to noon up to ~70 cm-3 for the highest nightside values around midnight. The azimuthal ion velocities vi,Θ varies from ~28-32 km/s at the lowest dayside values around noon to ~36-40 km/s at the highest nightside values around midnight. This gives an azimuthal ion velocity difference between noon and midnight of Δvi,Θ ~5-10 km/s. The day/night asymmetry is suggested to be due to dust-plasma interaction.

Dominance status in female ring-tailed lemurs (Lemur catta) has a pervasive effect upon social organization, however the proximate mechanisms underlying female rank-relations remain poorly understood. I investigated how four such attributes - weight, age, agonistic frequency, and fecal testosterone levels - relate to female rank-order wild ring-tailed lemurs at the Beza Mahafaly Special Reserve, Madagascar. My results indicated that: (1) The mean weight of high-ranking females is significantly greater than in lower-ranking females; (2) The relationship of age in relation to rank follows an inverted J-shaped pattern, with old adults attaining the highest average rank, followed by prime adults, young adults, and very old adults; (3) Significant, positive correlations between rank and rates of agonism exist in four of the six study groups; and (4) The effect of rank on mean testosterone concentration was significant in one social troop, in which the two highest ianking females exhibited significantly lower mean testosterone levels.

This paper deals with the development of the convolution ring and the construction of a field from this ring.

The study of some acylurea derivatives of 2-amino-3-alkylamino- and -3-arylamino-1,4-naphthoquinones was undertaken to determine the course of reaction under conditions similar to those used by J. R. Hoover and A. R. Day to prepare 2-alkyl-1H-naphth[2,3-d] imidazole-4.9-diones from 2-acylamino-3-amino-1,4-naphthoquinones.

Thesis advisor: Marc L. Snapper / Chapter 1: Over the past 100 years, ring expansion chemistry with non-stabilized diazoalkanes has grown slowly. While the intrinsic hazards and stigma associated with the use of diazoalkanes has been a serious impediment to more widespread development, a number of groups have made significant advances over the years. This chapter aims to provide a brief historical account of the most significant developments related to diazoalkane- based ring expansion methods. Chapter 2: The construction of stereogenic centers adjacent to ketones remains a challenging synthetic problem for chemists. Deficiencies with regard to reaction scope, efficiency, and generality remain. In contrast to the majority of other methods in the literature, stereoselective insertion of diazoalkanes provides a pathway to directly access enantiomerically enriched α-substituted cycloalkanones. In this chapter, an account of how we developed the first catalytic asymmetric diazoalkane-based ring expansion reactions is presented. Ring expansion of unfunctionalized cycloalkanones with diazoalkanes efficiently affords α-aryl substituted cycloalkanones with high enantiopurity. Additionally, this work led to the synthesis of new chiral bis(oxazoline) ligands and the discovery of a rapid method to assay the concentration of diazoalkane solutions. Chapter 3: Single-carbon ring expansion is a powerful synthetic disconnection, allowing chemists to construct or purchase the lower homologue of a ring system before expanding to the target ring size. Starting from a smaller ring size can often allow access to a broader array of transformations that proceed with greater stereoselection. In our approach to a class of natural products bearing a cis-decalin core, we successfully implemented a catalytic regioselective single-carbon ring expansion reaction in the context of an advanced synthetic intermediate. This chapter describes the experimental details behind the first catalytic single carbon cyclopentanone homologations and how we extended the method to more complex substrates. Chapter 4: Catalytic activation of sp2 hybridized electrophiles by nucleophilic catalysts has been studied extensively and proceeds through a well-defined mechanistic pathway. In constrast, activation of sp3 hybridized electrophiles in a similar fashion with small-molecule organocatalysts remains an elusive endeavor for chemists. This chapter describes prelimi- nary studies towards this lofty goal and how we discovered a new class of imidazole-based catalysts. Thorough mechanistic studies with the newly discovered catalysts ultimately proved that the reactions proceeded through a pathway that does not involve electrophile activation. However, inexpensive and commercially available imidazolium salts were found to catalyze Williamson etherification reactions under mild conditions through a mechanism that involves an unusual imidazolium alkoxide ion-pair. / Thesis (PhD) — Boston College, 2013. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.