The first principle

The historical association of epigenesis with embryonic development has been so close that the two terms are sometimes taken as synonymous, and this has been unfortunate because it has probably prevented biologists from realising that a convergent increase of complexity is a universal feature of life. The definitions of life which have appeared in the last 200 years (starting with Lamarck s entry) have produced a long list of supposedly essential characteristics (heredity, metabolism, reproduction, homeostasis, adaptation, autopoiesis, etc.), but none of them has explicitly mentioned epigenesis (for a list of such definitions see Appendix). 

Modern biology has already acknowledged that complexity is at the very heart of life, but semantic biology goes further than that. It states that what is crucial to life is not complexity as such, but the ability to produce a convergent increase of complexity. The first principle of semantic biology, in short, is nothing less than a new definition of life. 

---

Watson S C and Carter E A 2000 Linear-scaling parallel algorithms for the first principles treatment of metals Comp. Pbys. Common. 128 67-92... 

Ultrasonic Spectroscopy. Information on size distribution maybe obtained from the attenuation of sound waves traveling through a particle dispersion. Two distinct approaches are being used to extract particle size data from the attenuation spectmm an empirical approach based on the Bouguer-Lambert-Beerlaw (63) and a more fundamental or first-principle approach (64—66). The first-principle approach implies that no caHbration is required, but certain physical constants of both phases, ie, speed of sound, density, thermal coefficient of expansion, heat capacity, thermal conductivity. 

Ab initio methods, unlike either molecular mechanics or semi-empirical methods, use no experimental parameters in their computations. Instead, their computations are based solely on the laws of quantum mechanics—the first principles referred to in the name ah initio—and on the values of a small number of physical constants ... 

At this point, it may be useful to remind ourselves of an important caveat that is the first principle of kinetics nineties cannot prove a hypothetical mechanism. Kinetic experiments can only rule out various alternative hypotheses because they don t fit the data. However, through thoughtful kinetic studies, a process of elimination of alternative hypotheses leads ever closer to the reality. 

The scope of the early papers was to use the SK approach to accurately interpolate the results of first principles calculations of the energy bands and densities of states. An important characteristic of these calculations is that the first, second, and third nearest neighbor interactions are treated as independent parameters, which is advantageous for minimizing the rms deviation from the first principles bands. 

Figure El shows a data set which contains one data point, A, with significantly higher leverage and one data point, B, with significantly lower leverage than the other points in the data set. Also shown is the first principle component for the data set.

In many cases one can apply the first principles of thermodynamics and chemical kinetics to natural systems only with caution. The reason... 

Using the first-principles molecular-dynamics simulation, Munejiri, Shimojo and Hoshino studied the structure of liquid sulfur at 400 K, below the polymerization temperature [79]. They found that some of the Ss ring molecules homolytically open up on excitation of one electron from the HOMO to the LUMO. The chain-like diradicals S " thus generated partly recombine intramolecularly with formation of a branched Sy=S species rather than cyclo-Ss- Furthermore, the authors showed that photo-induced polymerization occurs in liquid sulfur when the Ss chains or Sy=S species are close to each other at their end. The mechanism of polymerization of sulfur remains a challenging problem for further theoretical work. 

As expected, the C-C bond lengA widens significantly for the rotational transition state. Here, the agreement between the semi-empirical MNDO results and the first-principles LDF results is remarkable. The discrepancy in the C-H bond length remains, but the trend of a small bond shortening from the ground state to the rotational transition state can be found for both the MNDO and the LDF calculation. 

The interdigital feed can be fed in a counter-flow or co-flow orientation the first principle is realized in metal/stainless steel or silicon/stainless steel devices [39, 41], the latter in glass chip devices [40, 44 6]. 

Group I relies, as said before, on the reductionistic ideal that everything, in the field of chemistry, is amenable to the first principles and that a correct applications of the principles, accompanied by the necessary computational effort, will give the answer one is searching. It is a rigourous approach, based on quantum mechanical principles, in which the elements of the computation have no cognitive status, unless when employed to get numerical values of physical observables or of other quantities having a well defined status in the theory. 

The first-principles calculation of NIS spectra has several important aspects. First of all, they greatly assist the assignment of NIS spectra. Secondly, the elucidation of the vibrational frequencies and normal mode compositions by means of quantum chemical calculations allows for the interpretation of the observed NIS patterns in terms of geometric and electronic structure and consequently provide a means of critically testing proposals for species of unknown structure. The first-principles calculation also provides an unambiguous way to perform consistent quantitative parameterization of experimental NIS data. Finally, there is another methodological aspect concerning the accuracy of the quantum chemically calculated force fields. Such calculations typically use only the experimental frequencies as reference values. However, apart from the frequencies, NIS probes the shapes of the normal modes for which the iron composition factors are a direct quantitative measure. Thus, by comparison with experimental data, one can assess the quality of the calculated normal mode compositions. 

Thus far it has not been possible to derive from the first principles the coalescence rate function for preferential combination of pellet species of different sizes. Kapur (K4) has proposed an ad hoc rate function in continuous sample space as follows ... 

The complete theory of catalysis, which would start with the isolated reaction participants, was not available until now because of the lack of adequate knowledge of the participants themselves (even the complete theory of the isolated participants, starting from the first principles, is still lacking). However, in analogy with the homogeneous chemical reactions one can expect that the quantum chemical approach, based on the semiempirical quantum mechanical methods, could be a prospective one. 

After all, even in the first case we deal with the interaction of an electron belonging to the gas particle with all the electrons of the crystal. However, this formulation of the problem already represents a second step in the successive approximations of the surface interaction. It seems that this more or less exact formulation will have to be considered until the theoretical methods are available to describe the behavior both of the polyatomic molecules and the metal crystal separately, starting from the first principles. In other words, a crude model of the metal, as described earlier, constructed without taking into account the chemical reactivity of the surface, would be in this general approach (in the contemporary state of matter) combined with a relatively precise model of the polyatomic molecule (the adequacy of which has been proved in the reactivity calculations of the homogeneous reactions). 

A straightforward definition of the term ab initio is from the beginning , from the first principles . Ab initio calculation of some property implies not using any experimental data or input, but relating the calculated property only to the fundamental constants entering the applied quantum-physical laws. 

Ruskin, John. 1862. Unto this Last Four Essays on the First Principles of Political Economy. London Smith, Elder. 

Molecular mechanics force fields rest on four fundamental principles. The first principle is derived from the Bom-Oppenheimer approximation. Electrons have much lower mass than nuclei and move at much greater velocity. The velocity is sufficiently different that the nuclei can be considered stationary on a relative scale. In effect, the electronic and nuclear motions are uncoupled, and they can be treated separately. Unlike quantum mechanics, which is involved in determining the probability of electron distribution, molecular mechanics focuses instead on the location of the nuclei. Based on both theory and experiment, a set of equations are used to account for the electronic-nuclear attraction, nuclear-nuclear repulsion, and covalent bonding. Electrons are not directly taken into account, but they are considered indirectly or implicitly through the use of potential energy equations. This approach creates a mathematical model of molecular structures which is intuitively clear and readily available for fast computations. The set of equations and constants is defined as the force... 

Simplified mathematical models These models typically begin with the basic conservation equations of the first principle models but make simplifying assumptions (typically related to similarity theory) to reduce the problem to the solution of (simultaneous) ordinary differential equations. In the verification process, such models must also address the relevant physical phenomenon as well as be validated for the application being considered. Such models are typically easily solved on a computer with typically less user interaction than required for the solution of PDEs. Simplified mathematical models may also be used as screening tools to identify the most important release scenarios however, other modeling approaches should be considered only if they address and have been validated for the important aspects of the scenario under consideration. 

The first principle of dose-response determination in inhalation toxicology is based on Haber s rule, which states that responses to an inhaled toxicant will be the same under conditions where C varies in complementary manner to t (Haber, 1924). For example, if C t elicits a specific magnitude of the same response that is, Ct = K, where A is a constant for the stated magnitude of response (as shown in Figure 10.2). 

The first principle in hazard assessment is to have the data correspond as closely as possible to the real-life situation that is, the nearer the model to humans, the better the quality of the prediction of any potential hazards. The second principle should now also be clear to be able to translate toxicity to hazard, and to be able to manage such hazards, it is essential to know how the agent is to be used and the marketplace it is to be part of. It is hoped that this section has made these relationships clear. 

---