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Full-Text Articles in Engineering

In Situ Measurement Of Three-Dimensional Ion Densities In Focused Femtosecond Pulses, James Strohaber, Cornelis J. Uiterwaal Jan 2008

In Situ Measurement Of Three-Dimensional Ion Densities In Focused Femtosecond Pulses, James Strohaber, Cornelis J. Uiterwaal

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

We image spatial distribution of xenon ions in the focus of a laser beam of ultrashort, intense pulses in all three dimensions, with a resolution of three by twelve microns in the two transverse directions. This allows for studying ionization processes without spatially averaging ion yields. Our in situ ion imaging is also useful to analyze focal intensity profiles and to investigate the transverse modal purity of tightly focused beams of complex light. As an example, the intensity profile of a Hermite-Gaussian beam mode HG recorded with ions is found to be in good agreement with optical images.


Agricultural Systems: Agroecology And Rural Innovations For Development [Book Review], Charles A. Francis Jan 2008

Agricultural Systems: Agroecology And Rural Innovations For Development [Book Review], Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

To welcome yet another book on sustainable development, a reviewer must look for what is unique and what adds value to the volumes already published. In Agricultural Systems, editors Sieglinde Snapp and Barry Pound have assembled a collection of chapters that goes beyond the usual praise and criticism of the green revolution and the focus on economic development. Their book provides a first-hand story by people with lengthy experiences in the field, especially in Africa, who have developed and tested grassroots, participatory development approaches. The result is a valuable set of principles, strategies and case studies that paint a new …


The Highly Similar Arabidopsis Homologs Of Trithorax Atx1 And Atx2 Encode Proteins With Divergent Biochemical Functions, Abdelaty Saleh, Raul Alvarez-Venegas, Mehtap Yilmaz, Oahn-Le, Guichuan Hou, Monther Sadder, Ayed Al-Abdallat, Yuannan Xia, Guoqinq Lu, Istvan Ladunga, Zoya Avramova Jan 2008

The Highly Similar Arabidopsis Homologs Of Trithorax Atx1 And Atx2 Encode Proteins With Divergent Biochemical Functions, Abdelaty Saleh, Raul Alvarez-Venegas, Mehtap Yilmaz, Oahn-Le, Guichuan Hou, Monther Sadder, Ayed Al-Abdallat, Yuannan Xia, Guoqinq Lu, Istvan Ladunga, Zoya Avramova

Nebraska Center for Biotechnology: Faculty and Staff Publications

Gene duplication followed by functional specialization is a potent force in the evolution of biological diversity. A comparative study of two highly conserved duplicated genes, ARABIDOPSIS TRITHORAX-LIKE PROTEIN1 (ATX1) and ATX2, revealed features of both partial redundancy and of functional divergence. Although structurally similar, their regulatory sequences have diverged, resulting in distinct temporal and spatial patterns of expression of the ATX1 and ATX2 genes. We found that ATX2 methylates only a limited fraction of nucleosomes and that ATX1 and ATX2 influence the expression of largely nonoverlapping gene sets. Even when coregulating shared targets, ATX1 and ATX2 may employ different …