Optimal Scaling of Interaction Effects in Generalized Linear Models

Multiplicative interaction models, such as Goodman's RC(M) association models, can be a useful tool for analyzing the content of interaction effects. However, most models for interaction effects are only suitable for data sets with two or three predictor variables. Here, we discuss an optimal scaling model for analyzing the content of interaction effects in generalized linear models with any number of categorical predictor variables. This model, which we call the optimal scaling of interactions (OSI) model, is a parsimonious, one-dimensional multiplicative interaction model. We discuss how the model can be used to visually interpret the interaction effects. Two empirical data sets are used to show how the results of the model can be applied and interpreted. Finally, several multidimensional extensions of the one-dimensional model are explored.

Optimal Scaling of Interaction Effects in Generalized Linear Models

Multiplicative interaction models, such as Goodman's RC(M) association models, can be a useful tool for analyzing the content of interaction effects. However, most models for interaction effects are only suitable for data sets with two or three predictor variables. Here, we discuss an optimal scaling model for analyzing the content of interaction effects in generalized linear models with any number of categorical predictor variables. This model, which we call the optimal scaling of interactions (OSI) model, is a parsimonious, one-dimensional multiplicative interaction model. We discuss how the model can be used to visually interpret the interaction effects. Two empirical data sets are used to show how the results of the model can

Agro-waste as source of fine and industrial chemicals: synthesis of 2-formyl-6 hydroxybenzoic acid and 4-methoxyisobenzofuran-1,3-dione from cashew nut shell liquid

This paper reports on the synthesis of 2-formyl-6-hydroxybenzoic acid (8) and 4 methoxyisobenzofuran-1,3-dione (10) from a renewable natural material Cashew Nut Shell Liquid (CNSL) achieved in five and seven steps, respectively. Anacardic acid was isolated from CNSL, dimethoxylated into (E)-methyl 2-methoxy-6-(pentadec-8-enyl)benzoate which was subsequently hydrogenated into methyl 2-methoxy-6-pentadecylbenzoate. Benzylic bromination of the methoxyester, and dehydrobromination afforded (E)-methyl 2-methoxy-6-(pentadec-1-enyl)benzoate which upon ozonolysis gave methyl 2-formyl-6-methoxybenzoate. Oxidation and dehydration of 8 formed methoxyphthalic anhydride (10). The work reported in this paper has further demonstrated the resourcefulness of cashew nut shell liquid as a renewable natural resource for synthesis of fine and industrial chemicals.Keywords: Anacardium occidentale, Cashew Nut Shell Liquid, Anacardic acid, 2 formyl-6-methoxybenzoate, methoxyphthalic anhydrid

Keuzes voor de lange termijn

Op vijf beleidsterreinen hebben het CPB en het SCP een toekomstverkenning voor het kabinet gemaakt. Dit artikel geeft de hoofdlijnen van de CPB-bijdrage

Modification of maleic anhydride grafted polyethylene with 1,4-diaminobutane in near critical propane

Granules of high density polyethylene grafted with 0.17 wt.% maleic anhydride (PEMA) were modified with an excess of 1,4-diaminobutane (DAB) by impregnation from near critical propane. After formation of amic acid groups, the excess of diaminobutane was extracted with a near critical propane–ethanol mixture (95/5 wt.%). Finally, the obtained PEMA–DAB was imidised quantitatively to the corresponding imide (PEMI) in the melt. The obtained PEMI showed no increased gel content with respect to the PEMA. The presence of primary amine groups was indirectly proven by selective extraction experiments. It appeared that PEMI samples had reacted with the anhydride groups of styrene-MA copolymer (SMA) during melt blending of SMA with PEMI, while the PEMA had not reacted. SMA/PEMI 80/20 blends consisted of a continuous SMA phase and PEMI droplets with a diameter of less than 1 μm. SMA/PEMA 80/20 blends showed a course morphology of PEMA strings in a continuous SMA phase. With this article we have shown that this new technique for the chemical modification of swollen HDPE particles in near critical propane has proven to be much better than the conventional modification in the melt, when it comes to avoiding crosslinking

Efficiency of free energy calculations of spin lattices by spectral quantum algorithms

Quantum algorithms are well-suited to calculate estimates of the energy spectra for spin lattice systems. These algorithms are based on the efficient calculation of the discrete Fourier components of the density of states. The efficiency of these algorithms in calculating the free energy per spin of general spin lattices to bounded error is examined. We find that the number of Fourier components required to bound the error in the free energy due to the broadening of the density of states scales polynomially with the number of spins in the lattice. However, the precision with which the Fourier components must be calculated is found to be an exponential function of the system size.Comment: 9 pages, 4 figures; corrected typographical and minor mathematical error

Toward complete oral cavity cancer resection using a handheld diffuse reflectance spectroscopy probe

This ex-vivo study evaluates the feasibility of diffuse reflectance spectroscopy (DRS) for discriminating tumor from healthy tissue, with the aim to develop a technology that can assess resection margins for the presence of tumor cells during oral cavity cancer surgery. Diffuse reflectance spectra were acquired on fresh surgical specimens from 28 patients with oral cavity squamous cell carcinoma. The spectra (400 to 1600 nm) were detected after illuminating tissue with a source fiber at 0.3-, 0.7-, 1.0-, and 2.0-mm distances from a detection fiber, obtaining spectral information from different sampling depths. The spectra were correlated with histopathology. A total of 76 spectra were obtained from tumor tissue and 110 spectra from healthy muscle tissue. The first- A nd second-order derivatives of the spectra were calculated and a classification algorithm was developed using fivefold cross validation with a linear support vector machine. The best results were obtained by the reflectance measured with a 1-mm source-detector distance (sensitivity, specificity, and accuracy are 89%, 82%, and 86%, respectively). DRS can accurately discriminate tumor from healthy tissue in an ex-vivo setting using a 1-mm source-detector distance. Accurate validation methods are warranted for larger sampling depths to allow for guidance during oral cavity cancer excision.</p