Globally model-identifiable

A parameter 6i of 0 is globally model-identifiable at 0 for model class C and input F if ... 

In other words, 6 is uniquely specified by F and V. If Oi is globally model-identifiable at 0, then it is also model-identifiable at 0. ... 

One weakness of the developed model approach is the central, one-dimensional optimisation that assumes the same target function for all participants. The model identifies possible economic and environmental benefits of a hydrogen infrastructure build-up by determining the global optimum for the whole system instead of the... 

An important block of the MBWB is the methods of determination of various parameters of the water cycle. Such methods are based on the use of surface, satellite, and airborne measurements. The MBWB used as a global model makes it easier to understand the role of the oceans and land in the hydrological cycle, to identify the main factors that control it, as well as to trace the dynamics of its interaction with plants, soil, and topographic characteristics of the Earth surface. It is based on the interaction between the elements of the water cycle, and takes natural and anthropogenic factors into account by means of information interfaces with other units of the global model (Krapivin and Kondratyev, 2002). 

A subtle concept, not readily apparent from the transfer function [Eq. (1.79)], is that model identifiability also depends on the shape of the input function, [u(t, p)] (Godfrey, Jones, and Brown, 1980). This property can be exploited, in the case of a single measurement system, to make a model identifiable by the addition of another input into the system. But care must be made in what is the shape of the second input. A second input having the same shape as the first input will not make an unidentifiable model identifiable. If, for example, a second bolus input into Compartment 2 of Model B in Fig. 1.13 were added at the same time as the bolus input into Compartment 1, the model will still remain unidentifiable. If, however, the input into Compartment 1 is a bolus and the input into Compartment 2 is an infusion the model will become globally identifiable. But, if the inputs are reversed and the input into Compartment 1 is an infusion and the input into Compartment 2 is a bolus, the model becomes globally identifiable only if there is an independent estimate of the volume of distribution of the central compartment. Hence, one way to make an unidentifiable model identifiable is to use another route of administration. 

Thus, explanation of the ice-core records demands a creative interaction with other fields of earth system science. We identify two such fields as crucial. The first is global modeling, which is a standard approach to climate change problems (both present / future and past) and is being actively extended to include interactions of the biogeochemical cycles with climate. The second is Quaternary science in the broad sense, especially insofar as Quaternary paleo-environmental records have been standardized and compiled on a global scale. Quaternary scientists have amassed data from widely distributed natural archives such as marine and lacustrine sediments which, when suitably compiled, yield spatially extensive information about many aspects of climate, ecosystem composition, and even some indicators of atmospheric composition such as the... 

Variations of these indicators over time ean oeenr dne to changes in emissions, but they can also be due to meteorological variability and to changes in the measurement method employed. Signal-to-noise ratio is a eritioal issue for all of the indicators identified above dne to the global natnre of the airshed for atmospherie Hg and the regional-to-loeal nature of proposed emission rednctions. The development and use of numerieal model simulations of atmospherie Hg emissions, transport, transformations, and deposition should be used to measure pertinent indieators and to better understand the fundamental atmospherie proeesses that affeet Hg dynamics. 

The vast majority of research focused on selenium in biology (primarily in the fields of molecular biology, cell biology, and biochemistry) over the past 20 years has centered on identification and characterization of specific selenoproteins, or proteins that contain selenium in the form of selenocysteine. In addition, studies to determine the unique machinery necessary for incorporation of a nonstandard amino acid (L-selenocysteine) during translation also have been central to our understanding of how cells can utilize this metalloid. This process has been studied in bacterial models (primarily Escherichia colt) and more recently in mammals in vitro cell culture and animal models). In this work, we will review the biosynthesis of selenoproteins in bacterial systems, and only briefly review what is currently known about parallel pathways in mammals, since a comprehensive review in this area has been recently published. Moreover, we summarize the global picture of the nonspecific and specific use of selenium from a broader perspective, one that includes lesser known pathways for selenium utilization into modified nucleosides in tRNA and a labile selenium cofactor. We also review recent research on newly identified mammalian selenoproteins and discuss their role in mammalian cell biology. 

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