Drawback

None of the aforementioned five methods ought to be mutually exclusive. A regulatory body can incorporate more than one of the techniques and/or apply different processes to different and specific issues. It is, therefore, important to highlight the limitations and drawbacks of each before drawing any conclusions. 

Croup dynamics tend to give rise to a number of issues. In a group environment there exists a pressure to avoid contradicting the points of views of the majority, albeit not always explidUy. As a result, not all of the members of a group can contribute to a robust and creative solution-oriented process. One of the reasons for what Van de Ven and Delbecq call inhibitory influences - those that prevent a dissenting member from contributing - comes from the fact that the other members 

Angrist, S.W. (1995) Iowa market takes stock of presidential candidates , The Wall Street Journal (28 August). Angrist then quotes Steven Feinstein, assistant professor of finance at Boston University s School of Management. 

Nelson, F.D. and Rietz, T.A. (2008) Prediction market accuracy in the long run . International Journal of Forecasting, 24 285-300. The authors gathered national polls for the 1998 through 2004 U.S. Presidential elections and ask[ed] whether either the poll or a contemporaneous Iowa Electronic Markets vote-share market prediction [was] closer to the eventual outcome for the two-major-party vote split. [The authors compared] market predictions to 964 polls over the five Presidential elections since 1988. The market [was] closer to the eventual outcome 74% of the time. Further, the market significantly outperform[ed] the polls in every election when forecasting more than 100 days in advance.  

Van de Ven and Delbecq, Nominal vs. Interacting, p. 206, and Graefe and Armstrong, Four methods of prediction, p. 184. 

Caution must be used in extrapolating enzyme assays as a screening tool for different polymers since the enzymes have been paired to only one polymer. The initially selected enzymes may show significantly reduced activity towards modified polymers or different materials, even though more suitable enzymes may exist in the environment. Caution must also be used if the enzymes are not purified or appropriately stabilised or stored, since inhibition and loss of enzyme activity can occur [23]. 

Both GaN and AlN crystallize, in equilibrium, in the wurtzite structure, which exhibits an ABAB stacking sequence. 6H-SiC, however, exhibits a ABCACB stacking sequence, which is exposed to GaN nucleating on the (1100) surface. 

This fact, as we will see below, constitutes a major obstacle for the realization of high-quality GaN films on SiG(liOO). 

A further disadvantage is the rapid strain relaxation occurring in GaN films on SiC(liOO). The residual strain present even in thin GaN layers is negligibly small in comparison to that in GaN films on y-LiAlO2(100). As we will see in the subsequent chapter by Grahn, the comparatively large strain in the latter films is crucial for applications of these films for polarization-sensitive devices. Finally, for these applications, it is often desirable that the substrate is transparent at the energy of the GaN band gap, a property that 6H-SiC does not possess. 

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Many antibiotics are unsuitable for therapeutic use, frequently because of their general toxicity or as a result of other drawbacks such as instability, inadequate solubility or malabsorption. 

The major drawback of this identification method, as used to date, is that only a part of the useful information contained into original Bscan image, i.e. segmented Bscan image, is used for defect characterization. Moreover, it requires the availability of defect classification information (i.e. if the defect is volumetric or planar, e.g. a crack or a lack of fusion), which, generally, may be as difficult to obtain as the defect parameters themselves. Therefore, we... 

Although direct coupling of a camera to a scintillator can give acceptable results one of its major drawback is the degradation of the quantum noise mainly related to the low transmission of the optics. The following schematics summarizes the particles flux (photons and electrons) across the different stages of the detector ... 

A proximity focused image intensifier appears therefore as a good solution for both low and high energy applications it combines a sufficient gain to avoid noisy images due to a the quantum sink without some drawbacks of standard image intensifier. 

Manual ultrasonic testing offers the advantages of low equipment cost combined with the flexibility of the human operator to provide good access and complex scanning capability. However, a total reliance on the capabilities of the ultrasonic technician to visualise the physical situation leads to a number of drawbacks, including lack of accuracy and consistency of defect size and location measurements, lack of verification that the required scan coverage has been fully achieved, and lack of consistency in flaw classification. A further disadvantage is that the ultrasonic data is not permanently recorded there is therefore no opportunity for the data to be re-examined at a later date if required. 

In this paper we propose a multivariable regression approach for estimating ultrasound attenuation in composite materials by means of pulse-echo measurements, thus overcoming the problems with limited access that is the main drawback of through-transmission testing. 

The connnon tlnead to these designs is that a sample can be exposed to reaction conditions and then studied usmg surface science methods withont exposure to the ambient. The drawback to both of these designs is that the samples are still being analysed under UFIV conditions before and after the reaction under study. The need for in situ teclniiqnes is clear. 

Despite the drawbacks of chemical-fixation based procedures [21,24], most of our current knowledge on biological ultrastnicture relies on this approach. In contrast to cryopreparative procedures, chemical fixation does not require special skills and instrumentation. 

One-photon excitation has lunitations due to the unwanted out-of-focus fliiorophore absorption and bleaching, and light scattering. These drawbacks can be circumvented if multiphoton excitation of the fliiorophore is used. Since it increases with the nth power of the photon density, significant absorption of the exciting light will only occur at the focal point of the objective where the required high photon density for absorption is reached. Consequently, only... 

The main drawback of the chister-m-chister methods is that the embedding operators are derived from a wavefunction that does not reflect the proper periodicity of the crystal a two-dimensionally infinite wavefiinction/density with a proper band structure would be preferable. Indeed, Rosch and co-workers pointed out recently a series of problems with such chister-m-chister embedding approaches. These include the lack of marked improvement of the results over finite clusters of the same size, problems with the orbital space partitioning such that charge conservation is violated, spurious mixing of virtual orbitals into the density matrix [170], the inlierent delocalized nature of metallic orbitals [171], etc. 

A major drawback of MD and MC techniques is that they calculate average properties. The free energy and entropy fiinctions caimot be expressed as simple averages of fimctions of the state point y. They are directly coimected to the logaritlun of the partition fiinction, and our methods do not give us the partition fiinction itself Nonetheless, calculating free energies is important, especially when we wish to detennine the relative thenuodynamic stability of different phases. How can we approach this problem ... 

Master equation methods are not tire only option for calculating tire kinetics of energy transfer and analytic approaches in general have certain drawbacks in not reflecting, for example, certain statistical aspects of coupled systems. Alternative approaches to tire calculation of energy migration dynamics in molecular ensembles are Monte Carlo calculations [18,19 and 20] and probability matrix iteration [21, 22], amongst otliers. 

A major drawback to the approaches that use preconstructed PESs is that there are many more interesting systems undergoing reactive dynamical processes than there are available PESs. It would be much better if the electronic structure part of the problem, which provides the forces for the nuclear dynamics, could be performed simultaneously with the dynamics part, thus making possible the treatment of systems for which preconstructed PESs... 

One drawback is that, as a result of the time-dependent potential due to the LHA, the energy is not conserved. Approaches to correct for this approximation, which is valid when the Gaussian wavepacket is narrow with respect to the width of the potential, include that of Coalson and Karplus [149], who use a variational principle to derive the equations of motion. This results in replacing the function values and derivatives at the central point, V, V, and V" in Eq. (41), by values averaged over the wavepacket. 

The basis consisting of the adiabatic electronic functions (we shall call it bent basis ) has a seiious drawback It leads to appearance of the off-diagonal elements that tend to infinity when the molecule reaches linear geometry (i.e., p 0). Thus it is convenient to introduce new electronic basis functions by the transformation... 

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