An investigation of the free reading of middle grade children

Thesis (M.A.)--Boston University, 1947. This item was digitized by the Internet Archive

\u3ci\u3eMcphersonarcys\u3c/i\u3e, a New Genus for \u3ci\u3ePentatoma Aequalis\u3c/i\u3e Say (Heteroptera: Pentatomidae)

A new monotypic genus, Mcphersonarcys is erected to hold Pentatoma aequalis Say, a species formerly placed in the genus Hymenarcys. Based on the distribution of 19 character-states Hymenarcys forms a clade with its sister genus Coenus. Both genera are related to the large genus Euschistus. Mcphersonarcys is basal to Euschistus, whereas the clade with Hymenarcys and Coenus is derived. Removal of P. aequalis to a new genus resolves the paraphyly of Hymenarcys sensu lato

Deep drilling into a Hawaiian volcano

Hawaiian volcanoes are the most comprehensively studied on Earth. Nevertheless, most of the eruptive history of each one is inaccessible because it is buried by younger lava flows or is exposed only below sea level. For those parts of Hawaiian volcanoes above sea level, erosion typically exposes only a few hundred meters of buried lavas (out of a total thickness of up to 10 km or more).Available samples of submarine lavas extend the time intervals of individual volcanoes that can be studied. However, the histories of individual Hawaiian volcanoes during most of their ~1-million-year passages across the zone of melt production are largely unknown

Introduction to special section: Hawaii Scientific Drilling Project

Intraplate or "hot spot" volcanic island chains, exemplified by Hawaii, play an important role in plate tectonic theory as reference points for absolute plate motions, but the origin of these volcanoes is not explained by the plate tectonic paradigm [Engebretson et al., 1985; Molnar and Stock, 1987; Morgan, 1971, 1981, 1983; Wilson, 1963]. The most widely held view is that these chains of volcanoes form from magma generated by decompression melting of localized, buoyant upwellings in the mantle [Ribe and Christensen, 1994; Richards et al., 1988; Sleep, 1990; Watson and McKenzie, 1991] . These upwellings, or "plumes," are believed to originate at boundary layers in the mantle (e.g., at the core-mantle boundary or near the boundary at-670 km between the upper and lower mantle), and the cause of the buoyancy may be both compositional and thermal [Campbell and Griffiths, 1990; Griffiths, 1986; Richards et al., 1988; Watson and McKenzie, 1991]. Mantle plumes are responsible for about 10% of the Earth's heat loss and constitute an important mechanism for cycling mass from the deep mantle to the Earth's surface. Studies of the chemical and isotopic compositions of lavas from intraplate volcanoes, especially ocean island volcanoes, have contributed significantly to our knowledge of magma genesis in the mantle [Carmichael et al., 1974; Macdonald et al., 1983] and the compositional heterogeneity of the mantle [Allègre et al., 1983; Hart, 1988; Hart et al., 1986; Kurz et al., 1983]. Of particular importance is the identification of distinct compositional end members in the mantle, the origin and distribution of which provide insight into the long-term differentiation of the mantle-crust system, the recycling of oceanic crust and continental sediment into the mantle, and the history of the lithosphere [Allègre et al., 1995; Farley et al., 1992; Hart, 1988; Hofmann and White, 1982; McKenzie and O'Nions, 1983; Weaver, 1991; Zindler and Hart, 1986]

Changing Time History in Moving Boundary Problems

A class of diffusion-stress equations modeling transport of solvent in glassy polymers is considered. The problem is formulated as a one-phase Stefan problem. It is shown that the moving front changes like √t initially but quickly behaves like t as t increases. The behavior is typical of stress-dominated transport. The quasi-steady state approximation is used to analyze the time history of the moving front. This analysis is motivated by the small time solution

Pentatomidae (Heteroptera) of Honduras : a checklist with description of a new ochlerine genus

Through collecting, surveys of museum collections, and search of the literature, we are able to list 181 species of Pentatomidae as occurring within the boundaries of the Republic of Honduras. Most of these, 129, around 70%, are widespread in the American tropics. Twenty-nine species are new country records, reported for Honduras for the first time. Four species of pentatomids are endemic to Honduras including a new genus and species of ochlerine (Discocephalinae) herein described. Although a few species extend from South America into Honduras (the Gondwanan element), and a few from North America extend into Honduras (the Nearctic element), the most important faunal element is one which is native to nuclear Central America.Con colectas, revisiones de las colecciones de museos, y revisiones de literaturas, se puede enumerar 181 especies de Pentatomidae distribuidas dentro de los límites de la república de Honduras. La mayoría de éstos, 129, alrededor del 70%, se extienden en las zonas tropicales americanas. Veinte y nueve especies son nuevos registros en el país, reportados en Honduras por primera vez. Cuatro especies de pentatómidos son endémicas de Honduras incluyendo un nuevo género y especie de Ochlerini (Discocephalinae) adjunto descrito. Aunque algunas especies se extienden de Sudamérica a Honduras (el elemento de Gondwana), y algunas de Norteamérica se extienden dentro Honduras (el elemento neárctico), el elemento más importante de la fauna es aquel que es nativo del núcleo de la región centroamericana

Review of the genus Dendrocoris Bergroth with descriptions of new species (Pentatomidae: Heteroptera)

The procleticine genus Dendrocoris Bergroth is revised with the descriptions of three new species from the United States, D. nelsoni, Mexico, D. inermis, and Guatemala, D. guatemalensis. A diagnosis is provided for each species with notes on distribution and host plants. Akeyis provided for determination of all fourteen species

Free boundary problems in controlled release pharmaceuticals. I: diffusion in glassy polymers

This paper formulates and studies two different problems occurring in the formation and use of pharmaceuticals via controlled release methods. These problems involve a glassy polymer and a penetrant, and the central problem is to predict and control the diffusive behavior of the penetrant through the polymer. The mathematical theory yields free boundary problems which are studied in various asymptotic regimes

Controlled Drug Release Asymptotics

The solution of Higushi's model for controlled release of drugs is examined when the solubility of the drug in the polymer matrix is a prescribed function of time. A time-dependent solubility results either from an external control or from a change in pH due to the activation of pH immobilized enzymes. The model is described as a one-phase moving boundary problem which cannot be solved exactly. We consider two limits of our problem. The first limit considers a solubility much smaller than the initial loading of the drug. This limit leads to a pseudo-steady-state approximation of the diffusion equation and has been widely used when the solubility is constant. The second limit considers a solubility close to the initial loading of the drug. It requires a boundary layer analysis and has never been explored before. We obtain simple analytical expressions for the release rate which exhibits the effect of the time-dependent solubility