Microstructure and Magnetic Properties of Very Thin CoCr Films Deposited on Different Underlayers by rf-Sputtering

Very thin CoCr films deposited on different underlayers on glass disk substrates were studied by the magneto-optic Kerr effect, VSM, torque magnetometry and TEM selected area diffraction. Square or near square perpendicular loops were obtained from Co/Ti, CoCr/Au, CoCr/Al, CoCr/C and CoCr/Si films. TEM SAD study revealed that the crystalline structure is a key factor determining the magnetic anisotropy of the very thin CoCr films. In particular, the c-axis of the hep CoCr films which exhibit square perpendicular loops is perpendicular to the film plane whilst that of the CoCr films which exhibit a thin and flat perpendicular loop lies in the film plane. The texture of the very thin CoCr films deposited on different underlayers is mainly dependent on the structure and texture of underlayers. The relation between the structure of CoCr and its underlayers is discussed

Degeneracy in Candecomp/Parafac and Indscal Explained For Several Three-Sliced Arrays With A Two-Valued Typical Rank

The Candecomp/Parafac (CP) method decomposes a three-way array into a prespecified number R of rank-1 arrays, by minimizing the sum of squares of the residual array. The practical use of CP is sometimes complicated by the occurrence of so-called degenerate sequences of solutions, in which several rank-1 arrays become highly correlated in all three modes and some elements of the rank-1 arrays become arbitrarily large. We consider the real-valued CP decomposition of all known three-sliced arrays, i.e., of size p×q×3, with a two-valued typical rank. These are the 5×3×3 and 8×4×3 arrays, and the 3×3×4 and 3×3×5 arrays with symmetric 3×3 slices. In the latter two cases, CP is equivalent to the Indscal model. For a typical rank of {m,m+1}, we consider the CP decomposition with R=m of an array of rank m+1. We show that (in most cases) the CP objective function does not have a minimum but an infimum. Moreover, any sequence of feasible CP solutions in which the objective value approaches the infimum will become degenerate. We use the tools developed in Stegeman (2006), who considers p×p×2 arrays, and present a framework of analysis which is of use to the future study of CP degeneracy related to a two-valued typical rank. Moreover, our examples show that CP uniqueness is not necessary for degenerate solutions to occur

Polonaise

https://digitalcommons.library.umaine.edu/mmb-ps/3188/thumbnail.jp

Gram-Schmidt versus Bauer-Rutishauser in alternating least-squares algorithms for three-way data

FSW - Gezinsopvoeding - Ou

Monitoring the T-Cell Receptor Repertoire at Single-Clone Resolution

The adaptive immune system recognizes billions of unique antigens using highly variable T-cell receptors. The αβ T-cell receptor repertoire includes an estimated 10(6) different rearranged β chains per individual. This paper describes a novel micro-array based method that monitors the β chain repertoire with a resolution of a single T-cell clone. These T-arrays are quantitative and detect T-cell clones at a frequency of less than one T cell in a million, which is 2 logs more sensitive than spectratyping (immunoscope), the current standard in repertoire analysis. Using T-arrays we detected CMV-specific CD4+ and CD8+ T-cell clones that expanded early after viral antigen stimulation in vitro and in vivo. This approach will be useful in monitoring individual T-cell clones in diverse experimental settings, and in identification of T-cell clones associated with infectious disease, autoimmune disease and cancer

Anti-proliferative action of vitamin D in MCF7 is still active after siRNA-VDR knock-down

Background: The active form of Vitamin D, 1,25-dihydroxyvitamin D3(1,25D), has strong anti-proliferative effects, yet the molecular mechanisms underneath this effect remain unclear. In contrast, the molecular mechanism of 1,25D for the regulation of calcium homeostasis has principally been resolved, demonstrating a pivotal role for the vitamin D receptor (VDR). Results: We first addressed the question whether the anti-proliferative effects of 1,25D are influenced by VDR. Knockdown of VDR by siRNA did not affect the anti-proliferative effects of 1,25D in MCF7 breast cancer cells. This unanticipated finding led us to take an alternative approach using genome wide screens to study the molecular mechanisms of 1,25D in proliferation. For that purpose, four independently developed and stable 1,25D resistant MCF7 cell lines were analyzed. Array CGH identified a copy number alteration in a region of 13.5 Mb at chromosome 11q13.4-14.1 common to all four 1,25D resistant cell lines. Expression arrays revealed that no single gene was differentially expressed between the sensitive and resistant cells, but multiple membrane receptor signaling pathways were altered in the 1,25D resistant cell lines. Importantly, in the genome wide experiments neither VDR, CYP24A1 nor other known vitamin D signaling pathway genes were associated with 1,25D resistance. Conclusion: In conclusion, siRNA and genome wide studies both suggest that the anti-proliferative effects of 1,25D in MCF7 breast tumor cell lines do not rely on classical Vitamin D pathway per se

Developing a running prototype of a bio-economic farm model for a trade-off analysis of different nutrient management options for maize cultivation in East-Africa

Considering projected population trends, food requirements in East Africa will drastically increase in the coming decades (van Ittersum et al., 2016). One way to ensure supply will meet demand is by raising crop yields in the region. In East Africa, agricultural yields still have large potential to increase due to the large gaps between actual and potential yields. A recent study has shown that intensification of agriculture in regions with low current yields (such as in East Africa) is an option to reduce greenhouse gas emissions by avoiding or reducing agricultural land expansion into forests and/or grasslands, thus preserving carbon stocks (Van Loon, Hijbeek, ten Berge and Van Ittersum 2018, in prep). This is however only valid if higher yields are obtained with highly efficient use of fertilisers. For a successful implementation of such climate smart agricultural intensification, improved nutrient management options need to be economically viable for farmers in East Africa. It is however often unclear under which conditions agricultural intensification is beneficial for farmers’ income in sub saharan Africa (Marenya and Barrett, 2009; Place et al., 2003; Sheahan et al., 2013). Besides a number of good agricultural practices (such as improving planting densities and sound crop protection measures), farmers need to apply more nutrients to intensify production. The amounts of additional nutrients required represents the ‘nutrient gap’ between current nutrient applications and the total amount of nutrients removed from fields with increased yields (de Vries et al., 2017). Farmers can use several nutrient management options to close the nutrient gap (e.g. use mineral or organic fertilisers, split application of fertilisers, combine with local or hybrid seeds). The nutrient management option a farmer chooses not only affects his or her nutrient use efficiency (how much of the applied nutrients are recovered by the crop), but also his or her income generation and the contribution to greenhouse gas emissions. Some practices might be most beneficial for farmers’ income, but have a larger contribution to greenhouse gas emissions. Others might have the reversed effect. So far, trade-offs and/or synergies between farmers’ income and greenhouse gas mitigation as a function of nutrient management options have not been systematically assessed. Additionally, it is uncertain how such trade-offs or synergies might evolve over time, in cases where soil carbon and nutrient pools respond over longer time frames to the management exposed. We therefore address the following question: Can certain nutrient management practices be identified which are beneficial for both climate change mitigation and for farmers’ income in East Africa? The aim of this report is to develop a running prototype of a bio-economic model which can be used to assess trade-offs between yields, farmers ‘income and greenhouse gas emissions in function of different nutrient management options, both on the short and the long term. The proposed model will focus on nitrogen (N) as the main limiting nutrient, which is also highly relevant for greenhouse gas emissions (i.e. N2O). The model will be useful for R&D investors, agri-business (including fertiliser companies) and government agencies for ex ante assessment of specific nutrient management options