Hamilton's theory of turns revisited

We present a new approach to Hamilton's theory of turns for the groups SO(3) and SU(2) which renders their properties, in particular their composition law, nearly trivial and immediately evident upon inspection. We show that the entire construction can be based on binary rotations rather than mirror reflections.

O emprego de medias acumuladas na aplicacao do modelo de Horton.

The purpose of this paper is to illustrate the application of accumulated means in two of Horton's laws of drainage composition: law of stream length and law of stream slope. Data used in the analysis were obtained from 30 drainage basins developed in the Paulistano Plateau and in the Serra do Mar escarpment, in the State of Sao Paulo. It was found that the application of accumulated means provides results according to Horton.-from English summary

Concordatos preventivos : proyecto de ley y exposición de motivos /

Mode of access: Internet.

Nueva ley de concordatos preventivos, promulgada el día 25 de enero de 1916, con las modificaciones introducidas por Ley de diciembre 29 de 1916.

Mode of access: Internet.

Group law computations on Jacobians of hyperelliptic Curves

We derive an explicit method of computing the composition step in Cantor’s algorithm for group operations on Jacobians of hyperelliptic curves. Our technique is inspired by the geometric description of the group law and applies to hyperelliptic curves of arbitrary genus. While Cantor’s general composition involves arithmetic in the polynomial ring F_q[x], the algorithm we propose solves a linear system over the base field which can be written down directly from the Mumford coordinates of the group elements. We apply this method to give more efficient formulas for group operations in both affine and projective coordinates for cryptographic systems based on Jacobians of genus 2 hyperelliptic curves in general form.

Its place in property education : where does property law fit into property programs?

Property law is one of the key elements in any property-based degree program. In particular, an understanding of 'property law' is one of the required knowledge fields for inclusion in property programs accredited by professional institutes such as the Royal Institution of Chartered Surveyors, the Appraisal Institute and the Australian Property Institute. Despite the importance of property law as a cornerstone element of all property programs this aspect of the program is often approached from a more generic legal perspective with teaching resources used and pedagogical approach more aligned to the study of law that property. The specificity of this type of program is rarely adequately acknowledged. The question arises as to what the study of 'property law' entails and what the composition of a 'property law' subject should be. Replicating the methodology used by Placid and Weeks (2009) in their examination of the current composition of real estate law courses in the United States, this paper examines the current composition and pedagogical approach adopted by Australian universities based on the study of three Queensland property programs. In particular the curriculum, teaching resources used, assessment and engagement strategies are considered with a view to making improvements to the way these property law courses can be more effectively tailored to property students. It is anticipated that the outcomes of this paper will be of interest to all academics who are responsible for developing and delivering property law subjects and those who manage property programs in Australia and internationally.

Vapour composition and activities in Mg-Zn liquid alloy at 923 K

Vapour species effusing from a magnesia Knudsen cell containing Mg-Zn alloy at 923 K were condensed on a water cooled copper plate. The equilibrium composition of the vapour phase over the alloy was determined from chemical analysis of the condensate. The activity coefficients of both components in the alloy have been derived from the data using a modified Gibbs-Duhem relation. The ratio of saturation vapour pressures of pure Zn and Mg obtained from the analysis of alloy data agree well with values from the literature, providing an internal check on the accuracy of data obtained in this study. Both components of the alloy exhibit negative deviations from Raoult's law. The concentration-concentration structure factor of Bhatia and Thomton at zero wave vector, evaluated from the measurements, indicate the presence of MgZn2 type complex in the liquid state. The associated regular solution model has been used for the thermodynamic description of liquid Mg-Zn alloys.

Application of composition gradient solid electrolytes in sensors and thermodynamic measurements

New compos~tiong radient solid electrolytes are developed which have application in high temperature solid state galvanic sensors and provide a new tool for thermodynamic measurements. The electrolyte consists oi a solid solution between two ionic conductors with a common mobile ion and spatial variation in composition of otber coxup nents. Incorporation of the composite electrolyte in sensors permits the use oi dissimilar gas electrodes. It is demonsuated, both experimentall y and theoretically, that the composition gradient of the relativeiy immobile species does not give rise to a diffusion potential.The emi of a cell is determined by the activity of the mobile species at the two eiectrodes. The thermodynamic properties of solid solutions can be measured using the gradient solid electrolyte. The experimental stuay is based on model systems A?(COj)x(S04)l-x (A=Na,K),where S \.aria across the electrolyte. The functionally gradient solid electrolytes used for activity measurements consist of pure carbonate at one ena and the solid solution under stuav at the other. The identical vaiues of activity, obtained h m t hree different modes of operation of the ceil. indicate unit transport number for the ddi metal ion in the graciient electrolyte. Tlle activities in the solid solutions exhibit moderate positive deviations from Raoult 's law.

Structural Transformations, Composition Anomalies and a Dramatic Collapse of Linear Polymer Chains in Dilute Ethanol-Water Mixtures

Water-ethanol mixtures exhibit many interesting anomalies, such as negative excess partial molar volume of ethanol, excess sound absorption coefficient at low concentrations, and positive deviation from Raoult's law for vapor pressure, to mention a few. These anomalies have been attributed to different, often contradictory origins, but a quantitative understanding is still lacking. We show by computer simulation and theoretical analyses that these anomalies arise from the sudden emergence of a bicontinuous phase that occurs at a relatively low ethanol concentration of x(eth) approximate to 0.06-0.10 (that amounts to a volume fraction of 0.17-0.26, which is a significant range!). The bicontinuous phase is formed by aggregation of ethanol molecules, resulting in a weak phase transition whose nature is elucidated. We find that the microheterogeneous structure of the mixture gives rise to a pronounced nonmonotonic composition dependence of local compressibility and nonmonotonic dependence in the peak value of the radial distribution function of ethyl groups. A multidimensional free energy surface of pair association is shown to provide a molecular explanation of the known negative excess partial volume of ethanol in terms of parallel orientation and hence better packing of the ethyl groups in the mixture due to hydrophobic interactions. The energy distribution of the ethanol molecules indicates additional energy decay channels that explain the excess sound attenuation coefficient in aqueous alcohol mixtures. We studied the dependence of the solvation of a linear polymer chain on the composition of the water-ethanol solvent. We find that there is a sudden collapse of the polymer at x(eth) approximate to 0.05-a phenomenon which we attribute to the formation of the microheterogeneous structures in the binary mixture at low ethanol concentrations. Together with recent single molecule pulling experiments, these results provide new insight into the behavior of polymer chain and foreign solutes, such as enzymes, in aqueous binary mixtures.

Influence of composition on the structure and properties of Fe-Pd-P and Ni-Pd-P amorphous alloys

Ternary alloys of nickel-palladium-phosphorus and iron-palladium- phosphorus containing 20 atomic % phosphorus were rapidly quenched from the liquid state. The structure of the quenched alloys was investigated by X-ray diffraction. Broad maxima in the diffraction patterns, indicative of a glass-like structure, were obtained for 13 to 73 atomic % nickel and 13 to 44 atomic % iron, with palladium adding up to 80%.

Radial distribution functions were computed from the diffraction data and yielded average interatomic distances and coordination numbers. The structure of the amorphous alloys could be explained in terms of structural units analogous to those existing in the crystalline Pd₃P, Ni₃P and Fe₃P phases, with iron or nickel substituting for palladium. A linear relationship between interatomic distances and composition, similar to Vegard's law, was shown for these metallic glasses.

Electrical resistivity measurements showed that the quenched alloys were metallic. Measurements were performed from liquid helium temperatures (4.2°K) up to the vicinity of the melting points (900°K- 1000°K). The temperature coefficient in the glassy state was very low, of the order of 10^-4/°K. A resistivity minimum was found at low temperature, varying between 9°K and 14°K for Ni_x-Pd_80-x -P₂₀ and between 17°K and 96°K for Fe_x-Pd_80-x -P₂₀, indicating the presence of a Kondo effect. Resistivity measurements, with a constant heating rate of about 1.5°C/min,showed progressive crystallization above approximately 600°K.

The magnetic moments of the amorphous Fe-Pd-P alloys were measured as a function of magnetic field and temperature. True ferromagnetism was found for the alloys Fe₃₂-Pd₄₈-P₂₀ and Fe₄₄-Pd₃₆-P₂₀ with Curie points at 165° K and 380° K respectively. Extrapolated values of the saturation magnetic moments to 0° K were 1.70 µ_B and 2.10 µ_B respectively. The amorphous alloy Fe₂₃-Pd₅₇-P₂₀ was assumed to be superparamagnetic. The experimental data indicate that phosphorus contributes to the decrease of moments by electron transfer, whereas palladium atoms probably have a small magnetic moment. A preliminary investigation of the Ni-Pd-P amorphous alloys showed that these alloys are weakly paramagnetic.

The Paradox of Performative Immediacy: Law, Music, Improvisation

In a 1999 essay, J.M. Balkin and Sanford Levinson called for law to be considered as a performing art. Against or perhaps going further than Balkin and Levinson, this commentary claims that while engagement with performance practices in the arts, such as music, is of the utmost value to law and legal theory, we must not take for granted what it means to ‘‘perform’’. Uniting Jacques Derrida’s la Villette performance (with jazz legend, Ornette Coleman) with his writings on performativity in law, this commentary looks to the musical practice of improvisation to trouble the notion of performance as immediate and singular and to question taken for granted distinctions between text and performance, writing and music, composition and improvisation. The consequence of this refined understanding of the performative on legal theory and the actual practice of law is a reconceptualization of law as improvisation, that is, both singular and general, pre-existent and immediate, and a refocusing on the creativity that lies at the heart of law’s conservativism.

Congress composition and electoral advantage

In 2003, an electoral reform changed the mechanism to assign seats in the Colombian Congress. I simulate the 2006 Senate elections using the previous assignment mechanism to determine which senators benefited from the reform, i.e. would have not been elected had the reform not been made. With the results of the simulation, I use a regression discontinuity design to compare the senators that would have been barely elected anyways with those who would have lost, but were near to be elected. I check the differences in the amount of law drafts presented, the attendance to voting sessions, and a discipline index for each senator as proxy of their legislative behavior. I find that the senators benefiting from the reform present a different legislative behavior during the 4-year term with respect to the senators that would have been elected anyways. Since the differential legislative behavior cannot be interpreted as being better (worse) politician, I examine if the behavioral difference gives them an electoral advantage. I find no difference in the electoral result of 2010 Senate election in terms of the probability of being (re)elected in 2010, the share of votes, the share of votes within their party list, and the concentration of their votes. Additionally, I check the probability of being investigated for links with paramilitary groups and I find no differences. The results suggest that political reforms can change the composition of governing or legislative bodies in terms of performance, but it does not necessarily translate into an electoral advantage.

Atmospheric composition of West Africa: highlights from the AMMA program

The atmospheric composition of West Africa reflects the interaction of various dynamical and chemical systems (i.e. biogenic, urban, convective and long-range transport) with signatures from local to continental scales. Recent measurements performed during the African Monsoon Multidisciplinary Analyses (AMMA) observational periods in 2005 and 2006 provide new data which has allowed new insight into the processes within these systems that control the distribution of ozone and its precursors. Using these new data and recently published results, we provide an overview of these systems with a particular emphasis on ozone distributions over West Africa during the wet season.

Well-Alloyed PtFe/C Nanocatalysts of Controlled Composition and Same Particle Size: Oxygen Reduction and Methanol Tolerance

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)