Petrology at DSDP Leg 66 Holes

The sandstone petrology of Leg 66 samples provides insights into changes through time in the geology of the source regions along the Guerrero portion of the Middle America continental margin. This in turn constrains possible models of the evolution of the Middle America Trench (e.g., de Czerna, 1971; Malfait and Dinkleman, 1972; Karig, 1974). Primarily medium-grained sands and sandstones, representing the widest variety available of trench/trench slope settings and ages, were analyzed in both light and heavy mineral studies. Standard techniques were used as much as possible in order to compare results from other margins and from ancient rocks.

The evolutionary history of termites as inferred from 66 mitochondrial genomes

Termites have colonized many habitats and are among the most abundant animals in tropical ecosystems, which they modify considerably through their actions. The timing of their rise in abundance and of the dispersal events that gave rise to modern termite lineages is not well understood. To shed light on termite origins and diversification, we sequenced the mitochondrial genome of 48 termite species and combined them with 18 previously sequenced termite mitochondrial genomes for phylogenetic and molecular clock analyses using multiple fossil calibrations. The 66 genomes represent most major clades of termites. Unlike previous phylogenetic studies based on fewer molecular data, our phylogenetic tree is fully resolved for the lower termites. The phylogenetic positions of Macrotermitinae and Apicotermitinae are also resolved as the basal groups in the higher termites, but in the crown termitid groups, including Termitinae + Syntermitinae + Nasutitermitinae + Cubitermitinae, the position of some nodes remains uncertain. Our molecular clock tree indicates that the lineages leading to termites and Cryptocercus roaches diverged 170 Ma (153-196 Ma 95% confidence interval [CI]), that modern Termitidae arose 54 Ma (46-66 Ma 95% CI), and that the crown termitid group arose 40 Ma (35-49 Ma 95% CI). This indicates that the distribution of basal termite clades was influenced by the final stages of the breakup of Pangaea. Our inference of ancestral geographic ranges shows that the Termitidae, which includes more than 75% of extant termite species, most likely originated in Africa or Asia, and acquired their pantropical distribution after a series of dispersal and subsequent diversification events.

Vykopirovka s proektplana Kolaiskoĭ dachi razverstani︠ia︡ Dzhankoĭskoogo raǐona, na uchastky zemli otvedennykh za Nº Nº 106, 109, 66 i 66A

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Preparation and NMR spectra of four isomeric diformyl2.2]paracyclophanes (cyclophanes 66)

Four isomeric dialdehydes 4, readily available from cycloaddition of propiolic aldehyde (2) to 1,2,4,5-hexatetraene (1), were separated by chromatography and recrystallization, and were characterized by their spectroscopic data. The individual isomers can now be easily identified from their H-1 NMR spectra even if only one of them is present.

An algebraic formulation of static isotropy and design of statically isotropic 6–6 Stewart platform manipulators

In this paper, we present an algebraic method to study and design spatial parallel manipulators that demonstrate isotropy in the force and moment distributions. We use the force and moment transformation matrices separately, and derive conditions for their isotropy individually as well as in combination. The isotropy conditions are derived in closed-form in terms of the invariants of the quadratic forms associated with these matrices. The formulation is applied to a class of Stewart platform manipulator, and a multi-parameter family of isotropic manipulators is identified analytically. We show that it is impossible to obtain a spatially isotropic configuration within this family. We also compute the isotropic configurations of an existing manipulator and demonstrate a procedure for designing the manipulator for isotropy at a given configuration.

Magnetoresistance of FexNi80-xCr20 (50

The authors have measured longitudinal and transverse magnetoresistance (MR) of crystalline pseudo-binary alloys FexNi80-xCr20 (50

Determinación del costo del beneficio húmedo del café, en el departamento de Nueva Segovia, durante el ciclo agrícola 1965/66

El presente trabajo sirve como una modesta contribución a los estudios que sobre el cultivo del café y su beneficio deben todavía hacerse en Nicaragua y como tema de tesis para el autor. El objetivo fue investigar el costo de la fase húmeda del beneficio húmedo, conocida también con este ultimo nombre, en el departamento de Nueva Segovia. Para ello se elaboro una boleta con 7 secciones en base a las diferentes operaciones que se suceden durante el beneficio y los gastos variables y fijos que ellas ocasionan. Se determinaron los centros productores de café y se estimo encuestas del 10 al 20% de la superficie departamental sembrada con café, agrupando todas las explotaciones que siembran café en tres stratos: de 1 a 100 manzanas, de 100 a 500 manzanas y 500 y mas manzanas, de los cuales al primero correspondería el mayor porcentaje de la muestra, al segundo el porcentaje intermedio y al tercero, el menor. La encuesta se realizo del 23 de enero al 9 de febrero inclusive de 1966, actuando de empadronador único el autor del trabajo. Se obtuvo como muestra el 16.1% del área sembrada con café en el departamento y la información obtenida se vació en una manta-cartulina preparada al efecto. por municipio. Por aparte se obtuvo la misma información, por strato. La encuesta abarco un total de 34 productores propietarios de 42 fincas en las que se siembra café, las que se encuentran agrupadas en 36 unidades de explotación. Los datos recopilados convenientemente dieron como resultado que en el departamento de Nueva Segovia el costo del beneficio húmedo de 1 quintal oro de café en el ciclo agrícola 1965/66, fue de C$35.60 (Treinticinco córdobas y sesenta centavos de córdobas). La proporción en que los stratos se acercan o se alejan del promedio departamental se atribuye a la eficiencia o deficiencia de las técnicas administrativas empleadas.

Cruise Report 66-S-1

(PDF contains 3 pages.)

Cruise Report 66-S-2

(PDF contains 3 pages.)