Cross-classified factor

Finally, there are two families of factorial designs which depend on the combination mode of the factors. If it is possible to combine each level of one factor with each level of every other factor this is denoted cross-classified design. The second family consists of nested designs or hierarchical experiments. In those designs the levels of one factor may not be combined with all the levels of another factor. As an example consider an investigation performed by two laboratories (factor no. 1) which unfortunately cannot... 

Corrected sum of squares See total sum of squares. (Section 4.4) Cross-classified system In a multiway ANOYA when the measurements are made at every combination of each factor. (Section 4.8) Degrees of freedom The number of data minus the number of parameters calculated from them. The degrees of freedom for a sample standard deviation of n data is n — 1. For a calibration in which an intercept and slope are calculated, df=n — 2. (Sections 2.4.5, 5.3.1) Dependent variable The instrument response which depends on the value of the independent variable (the concentration of the analyte). (Section 5.2)... 

To illustrate this point, consider Table 9.2, which gives frequencies of patients in a clinical trial cross-classified according to treatment (A or B), strata of a factor with two levels and outcome (success or failure). The trial is perfectly balanced at baseline in that there are 100 patients within each stratum for each treatment. The odds ratios in stratum 1 and stratum 2 are... 

This block design, in which each treatment appears once in each row and once in each column, is known as a Latin square. It allows the separation of the variation into the between-treatment, between-block, between-time-of-day and random experimental error components. More complex designs are possible which remove the constraint of equal numbers of blocks and treatments. If there are more than three blocks and treatments a number of Latin square designs are obviously possible (one can be chosen at random). Experimental designs of the types discussed so far are said to be cross-classified designs, as they provide for measurements for every possible combination of the factors. But in other cases (for example when samples are sent to different laboratories, and are analysed by two or more different experimenters in each laboratory) the designs are said to be nested or hierarchical, because the experimenters do not make measurements in laboratories other than their own. Mixtures between nested and cross-classified designs are also possible. 

Bacteria produce chromosomady and R-plasmid (resistance factor) mediated P-lactamases. The plasmid-mediated enzymes can cross interspecific and intergeneric boundaries. This transfer of resistance via plasmid transfer between strains and even species has enhanced the problems of P-lactam antibiotic resistance. Many species previously controded by P-lactam antibiotics are now resistant. The chromosomal P-lactamases are species specific, but can be broadly classified by substrate profile, sensitivity to inhibitors, analytical isoelectric focusing, immunological studies, and molecular weight deterrnination. Individual enzymes may inactivate primarily penicillins, cephalosporins, or both, and the substrate specificity predeterrnines the antibiotic resistance of the producing strain. Some P-lactamases are produced only in the presence of the P-lactam antibiotic (inducible) and others are produced continuously (constitutive). 

In order to make justified risk management decisions, the first step is to classify the risks. This is often not an easy task. There is a balance between acceptability of a risk (both socially and regulatory based) and the chance that it occurs. In the case of allergen cross-contamination, this latter aspect is a crucial factor as risk management often focuses on reduction of the chance rather than avoidance. 

The influence of factors such as chemical structure, molecular weight, cross-linking and plasticizers in the glass transition of polymers can be related to the changes that they provoke on the free volume fraction, which, as we already know, reaches a critical value at the glass transition temperature. The factors affecting the glass transition can be classified into two types (1) molecular factors, i.e., those related to the chemical structure of the polymer chain, and (2) external or controllable factors. 

Clostridium bofulinum type C was firstly isolated by Bengston in 1922 (Bengston, 1922). In 1935, Mason and Robinson reported that C. bofulinum type C produced three different toxic factors, Cl, C2 and D (Mason and Robinson, 1935), although it had been considered at that time that other types of C. bofulinum, types A and B, produced only one antigenic type of the toxin. This was the first use of the term C2 toxin in the literature. Later on, Jansen applied this notion to the toxins produced by C. bofulinum C and Cp strains, which had been classified by immunological cross-neutralization produces Cl, C2 and D toxins and Cp only C2 toxin (Jansen, 1971). Thus, C2 toxin had been thought of as a botulinum neurotoxin until it was purified and characterized in 1980 (Ohishi etal., 1980). 

There is a definite association between the size of a primary melanoma lesion and the likelihood of metastases. The prognostic factor originally used to determine survival was based on the cross-sectional profile of the primary tumor. The cross-sectional profile could be evaluated if the deepest invasive tumor cells lay above or below the sweat glands. This assessment was further clarified by Clark, who described the relationship of depth of invasion of the cancer cells to the standard anatomic landmarks of the skin (Table 133-3). Clark s classification is a practical approach for patients with more superficial tumors, because tumors classified as Clark levels I through III seldom metastasize. That classification system has been criticized because of problems associated with practical measurements. Melanoma lesions that occur in the presence of lymphoid infiltration, fibrosis, or even the cells of preexisting nevi are difficult to assess with classic reference landmarks. 

Taguchi, F. et al., Mass spectrometry to classify non-small-cell lung cancer patients for clinical outcome after treatment with epidermal growth factor receptor tyrosine kinase inhibitors A multicohort cross-institutional study, J. Natl. Cancer Inst., 99(11), 838, 2007. 

Irradiation (e-beam or y-irradiation) is classified among the high-energy solid-state processes. Some similarities between mechanical milling and irradiation to compatibilize nonmiscible blends have been observed by different authors. 1- Smith et al. considered that these processes lead to the same phenomena (chain scission, cross-linking, amorphization), and they claimed that the factors influencing these phenomena (polymer chemical structure and temperature) are not dependent on the process. ... 

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