Land Grant Application- Worster, Thomas (Sanford)

Land grant application submitted to the Maine Land Office on behalf of Thomas Worster for service in the Revolutionary War, by their widow Susan.https://digitalmaine.com/revolutionary_war_me_land_office/2007/thumbnail.jp

Formation of Chimneys in Mushy Layers: Experiment and Simulation

In this fluid dyanmics video, we show experimental images and simulations of chimney formation in mushy layers. A directional solidification apparatus was used to freeze 25 wt % aqueous ammonium chloride solutions at controlled rates in a narrow Hele-Shaw cell (1mm gap). The convective motion is imaged with schlieren. We demonstrate the ability to numerically simulate mushy layer growth for direct comparison with experiments

Transformações da terra: para uma perspectiva agroecológica na história.

O artigo discute a constituição do campo da história ambiental, que se deu nos anos 70 em meio aos debates sobre a crise ecológica e a eclosão do movimento ambientalista. Esta história não aceita a noção de que as sociedades humanas não produzem alterações ambientais significativas, e interpela as condições específicas dessa interação recorrente. O sistema agroecológico representa um dos casos mais típicos de rearranjo da atividade humana sobre os ecossistemas naturais, em uma relação complexa de interação entre plantas nativas, vegetação forasteira, fertilidade dos solos e diversas práticas agrícolas. O itinerário dessas mudanças é essencial para se compreender a história do ponto de vista ambienta

A New Science for a Post-Frontier World

The driving force behind the North American frontier were waves of economic migrants from Europe and their offspring, competing against the indigenous people and eventually replacing them. But those waves were backed up by the power of the American and Canadian nation states, with their well-armed military, their well funded railroads, and other technology and capital. Science too was initially on the side of the invaders. But after World War One that frontier began to run out of free, abundant land. Then began what I will call a “post-frontier” science, especially ecological in content, that represented a very different attitude toward the white man’s conquest. Scientists like Frederick Clements, John C. Weaver, Paul Sears, and Stan Rowe, all natives to the Great Plains, laid the foundations for what is now a powerful critique of frontier agriculture. This article aims to summarize that critique briefly but focus mainly on the more recent work of Wes Jackson, founder and longtime president of the Land Institute. He has strongly criticized the frontier ethos for its the lack of understanding of the native ecology of the grasslands. In its place he has offered a vision of “perennial polyculture,” using nature as a model for agriculture in an era of limits. That model has not only been making a growing impact on American thinking but has now spread to other continents. Will the end of this frontier cycle and scientific reappraisal turn out to be what Jackson calls a “new agriculture,” one based on learning from the past and one that can change farming all over the world?The driving force behind the North American frontier were waves of economic migrants from Europe and their offspring, competing against the indigenous people and eventually replacing them. But those waves were backed up by the power of the American and Canadian nation states, with their well-armed military, their well funded railroads, and other technology and capital. Science too was initially on the side of the invaders. But after World War One that frontier began to run out of free, abundant land. Then began what I will call a “post-frontier” science, especially ecological in content, that represented a very different attitude toward the white man’s conquest. Scientists like Frederick Clements, John C. Weaver, Paul Sears, and Stan Rowe, all natives to the Great Plains, laid the foundations for what is now a powerful critique of frontier agriculture. This article aims to summarize that critique briefly but focus mainly on the more recent work of Wes Jackson, founder and longtime president of the Land Institute. He has strongly criticized the frontier ethos for its the lack of understanding of the native ecology of the grasslands. In its place he has offered a vision of “perennial polyculture,” using nature as a model for agriculture in an era of limits. That model has not only been making a growing impact on American thinking but has now spread to other continents. Will the end of this frontier cycle and scientific reappraisal turn out to be what Jackson calls a “new agriculture,” one based on learning from the past and one that can change farming all over the world?The driving force behind the North American frontier were waves of economic migrants from Europe and their offspring, competing against the indigenous people and eventually replacing them. But those waves were backed up by the power of the American and Canadian nation states, with their well-armed military, their well funded railroads, and other technology and capital. Science too was initially on the side of the invaders. But after World War One that frontier began to run out of free, abundant land. Then began what I will call a “post-frontier” science, especially ecological in content, that represented a very different attitude toward the white man’s conquest. Scientists like Frederick Clements, John C. Weaver, Paul Sears, and Stan Rowe, all natives to the Great Plains, laid the foundations for what is now a powerful critique of frontier agriculture. This article aims to summarize that critique briefly but focus mainly on the more recent work of Wes Jackson, founder and longtime president of the Land Institute. He has strongly criticized the frontier ethos for its the lack of understanding of the native ecology of the grasslands. In its place he has offered a vision of “perennial polyculture,” using nature as a model for agriculture in an era of limits. That model has not only been making a growing impact on American thinking but has now spread to other continents. Will the end of this frontier cycle and scientific reappraisal turn out to be what Jackson calls a “new agriculture,” one based on learning from the past and one that can change farming all over the world