Parsimony

Chem.) sparing substance, protein sparer. Sparren, m. rafter spar, sparsam, a. sparing, economical, close. Sparsamkeit,/. economy parsimony. Sparstoff, m. scarce (or rationed) material, sparstoffarm, a. low in scarce materials. 

These, such as the black box that was the receptor at the turn of the century, usually are simple input/output functions with no mechanistic description (i.e., the drug interacts with the receptor and a response ensues). Another type, termed the Parsimonious model, is also simple but has a greater number of estimatable parameters. These do not completely characterize the experimental situation completely but do offer insights into mechanism. Models can be more complex as well. For example, complex models with a large number of estimatable parameters can be used to simulate behavior under a variety of conditions (simulation models). Similarly, complex models for which the number of independently verifiable parameters is low (termed heuristic models) can still be used to describe complex behaviors not apparent by simple inspection of the system. 

Applications of the Theory.—As an illustration of the application of the foregoing prindples some predictions may be made regarding the structure of cyanite, andalusite and sillimanite, the three forms of Al2Si05. From the rule of parsimony we expect all aluminum octahedra to be similar and all silicon tetrahedra to be similar. Let the number of octahedra one comer of which is formed by the ith oxygen ion be a,- then the stoichiometries oxygen-aluminum ratio, 5 2, requires that... 

By far the most parsimonious, but nonstatistical, explanation for the observed pattern is that the titrations differ in selectivity, especially as regards basic and acidic impurities. Because of this, the only conclusion that can be drawn is that the true values probably lie near the lowest value for each batch, and everything in excess of this is due to interference from impurities. A more selective method should be applied, e.g., polarimetry or ion chromatography. Parsimony" is a scientific principle make as few assumptions as possible to explain an observation it is in the realm of wishful thinking and fringe science that combinations of improbable and implausible factors are routinely taken for granted. 

Theoretically it has been shown (Thayse, 1988) that the DDP formalism is closely related to a simpler form of horn clause logic, i.e., the propositional calculus. This would suggest that we could use the horn clause form to express some of the types of knowledge we are required to manipulate in combinatorial optimization problems. The explicit inclusion of state information into the representation, necessitates the shift from the simpler propositional form, to the first-order form, since we wish to parsimoniously represent properties that can be true, or take different values, in different states. By limiting the form to horn clauses, we are striving to retain the maximum simplicity of representation, whilst admitting the necessary expressive power. 

The principle of parsimonious parametrization should be applied, according to which the model with as few parameters as possible should be selected this is in accordance with the Wheeler recommendation the best model is the simplest one that works . This is also a guideline for making increasingly complex models stop when the model is sufficiently complex to get an adequate fit of the data. 

Herbstein, F. H. Structural Parsimony and Structuihi Variety Among Inclusion Complexes, 140, 107-139(1987). 

E. de Noord, The influence of data preprocessing on the robustness nd parsimony of multivariate calibration models. Chemom. Intell. Lab. Systems, 23 (1994) 65-70,... 

Structural Parsimony and Structural Variety Among Inclusion Complexes... 

Furthermore, there can be identified two opposing trends in model development. One is a trend toward more detailed models with higher fidelity to the real system, driven by the availability of highly resolved environmental data, increases in computer power, and progress in atmospheric and earth sciences. The other trend is toward models that are tailor-made to specific scientific questions or decision-making problems, driven by the philosophy of parsimony and the increase in the need for scientific results as a basis for decision-making in modem society. 

According to the creators, USEtox provides a parsimonious and transparent tool for human health and ecosystem characterization factor (CF) estimates. It has been carefully constructed as well as evaluated via comparison with other models and falls within the range of their results while being less complex. 

Jim Griesemer That is Sober s argument for parsimony that there are irreducible assumptions, process assumptions, that you have to put in to construct a cladogram in the first place. Unless he s wrong about that, I don t see that it supports your argument. 

Fig. 1.3. (Opposite) COI genes of strongylid and other nematodes. Aligned COI sequences (from Sukhdeo etal., 1997 (where each is designated by the GenBank accession number), except for Ascaris suum ASCOI and C. elegans CECOI which are from Okimoto et al. (1992), O. volvulus COI which is from Keddie etal. (1998) and B. malayiCO sequence which is unpublished data of the author) were analysed using maximum parsimony and neighbour joining.

Fig. 1.5. Delineation of Bursaphelenchus species. (A) Maximum parsimony phylogram of an analysis of the aligned ITS1 and ITS2 regions from Bursaphelenchus isolates. Branch lengths are given above each branch, and bootstrap support below. (B) As for (A) but using NJ analysis (logdet/paralinear distance correction). Adapted from Beckenbach etal. (1999).

FELSENSTEIN, J., Inferring phylogenies from protein sequences by parsimony, distance, and likelihood methods, Methods Enzymol., 1996, 266, 418-427. 

Macey, J.R. (2005) Plethodontid salamander mitochondrial genomics a parsimony evaluation of character conflict and implications for historical biogeography. Qadistics 21, 194—202. 

Because variables in models are often highly correlated, when experimental data are collected, the xrx matrix in Equation 2.9 can be badly conditioned (see Appendix A), and thus the estimates of the values of the coefficients in a model can have considerable associated uncertainty. The method of factorial experimental design forces the data to be orthogonal and avoids this problem. This method allows you to determine the relative importance of each input variable and thus to develop a parsimonious model, one that includes only the most important variables and effects. Factorial experiments also represent efficient experimentation. You systematically plan and conduct experiments in which all of the variables are changed simultaneously rather than one at a time, thus reducing the number of experiments needed. 

Control over the material s shape at the nanoscale enables further control over reactants access to the dopant, and ultimately affords a potent means of controlling function which is analogous to that parsimoniously employed by Nature to synthesize materials with myriad function with a surprisingly low number of material s building blocks. A nice illustration is offered by the extrusion catalytic polymerization of ethylene within the hexagonal channels of MCM-41 mesoporous silica doped with catalyst titanocene.36 The structure is made of amorphous silica walls spatially arranged into periodic arrays with high surface area (up to 1400 m2g 1) and mesopore volume >0.7 mLg-1. In this case, restricted conformation dictates polymerization the pore diameter... 

In line 29, the word parsimonious most nearly means... 

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