Time-window concept

Recently, Orosz et al. [136] reviewed and critically reevaluated some of the known mechanistic studies. Detailed mathematical expressions for rate constants were presented, and these are used to derive relationships, which can then be used as guidelines in the optimization procedure of the POCL response. A model based on the time-window concept, which assumes that only a fraction of the exponential light emission curve is captured and integrated by the detector, was presented. Existing data were used to simulate the detector response for different reagent concentrations and flow rates. 

Around acutely infarcted brain, there is an ischemic penumbra (Astrup et al. 1981). Here the blood flow is low, function depressed and the oxygen extraction fraction high. In other words, there is viable tissue with misery perfusion where the needs of the tissue are not being met The tissue may die or recover, depending on the speed and extent of restoration of blood flow. This concept opens up the possibility of a therapeutic time window during which restoration of flow or neuronal protection from ischemic damage might prevent both immediate cell death and the recruitment of neurons for apoptosis (see Ch. 21). 

Nonstationarity of time series s(t) implies that even if the time average of s(t) would look converged for a certain time regime, it should become a totally different value by extending the time window for which the time average of s(t) will be estimated. That is, rigorously, the concept of time average never... 

Another difficulty is caused by the application of Gibbs thermodynamic concept to nonequilibrium conditions of an adsorption layer, as it is done in many theoretical models (cf. Chapter 4). From non-equilibrium thermodynamics we learn (cf Eq. (2C.8) derived by Defay et al. (1966), Appendix 2C) that the diffusional transport causes an additional term to the Gibbs equation. However, this term seems to be negligible in many experiments. The experimental data discussed in Chapter 5, obtained from measurements in very different time windows, support the validity of Gibbs fundamental equation (2.33) also under non-equilibrium conditions. 

Baron JC, von Kummer R, del Zoppo GJ (1995) Treatment of acute ischemic stroke. Challenging the concept of a rigid and universal time window. Stroke 26 2219-2221... 

Obviously, two stages of data manipulation are required to obtain Zi j(o) as a function of frequency from the response of the systan to an arbitrary time domain perturbation first, the input and response functions must be sampled and recorded in the time window of interest, then the transform of each must be computed and the complex ratio calculated. In hard-wired Fourier transform units, the acquisition subsystem is an integral part of the unit, and this function normally can be ignored. If the experimenter is using a computer or microcomputer to perform these functions, the concepts of analog-to-digital conversion and computer interfacing (described briefly in Sections 3.1.3.2 and 3.1.3.3) must be used. 

The Photoassociation Process Time Window, Resonance Window, Concept of a Photoassociation Window... 

The concept is illustrated with the analysis of some organochlorine pesticides in wine. Figure 65 shows the capillary GC - AED trace in the chloor emission line (837 nm) of a wine extract. RTL conditions were adapted to the analysis and the identities were searched via a pesticide RTL database. A retention time window of 0.5 ( 0.25 min from the measured retention time) and the presence of chloor were introduced in the RTL dialogue box. From the search for the main peak eluting at 21.93 min (Table 7) it is clear that the smallest deviation is obtained for procymidone. The presence of this compound could be confirmed using RTL conditions in capillary GC-... 

For confirmation of target compounds, LC relative retention time criteria (retention time window <2.5%) and mass spectrometric identification criteria need to be fulfilled. The latter are based on the concept of identification points (EC, 2002). For accurate mass screening using TOF or Oibitrap MS instraments, no criteria are described. Recently, some propositions for these types of instraments were made by Nielen et al. (2007). For high-resolution screening (resolution >20,000 and a mass accuracy <5 mDa), these authors proposed two identification points. Each product ion (low-mass- resolution MS) also contributes two points. Tlius, acquiring a high-resoludon precursor ion in combination with at least one product ion and the LC relative retention time meets the minimum requirement of four identification points. 

As the specific surface area (Equation 2.24) and the heat transfer coefficient (Equation 2.21) increase with decreasing diameters, it follows that microstructured channel reactors are characterized by very short cooling times, thus improving temperature control and reducing the risk of reactor runaway. As a consequence, microstructured reactors can be operated under harsh reaction conditions such as high temperature and pressure. The chemical kinetics is speeded up drastically reducing the characteristic reaction time. This concept is often called novel process windows [20]. 

The situation may be illustrated well by the development of the public discourse on hydropower in Switzerland over the past few years. As 60% of Swiss electricity generation stems from hydropower, its environmental impacts have time and again raised political debates over the past 50 years. More recently, the liberalization of electricity markets has opened up new windows of opportunity for the development of new approaches of mitigation. One example of an integrative concept was developed by an interdisciplinary team of researchers in the late 1990s. It has been implemented in the currently operating eco-label for sustainably produced electricity in Switzerland (naturemade star). 

Adverse effects in children may result from exposure prior to conception (paternal and/or maternal), during prenatal development, or postnatally to the time of full maturity. Even within a given developmental stage, shorter intervals of exposure may determine susceptibility for particular outcomes. Different organ systems develop at different rates, but it has been shown that for each developmental stage, there are both broad windows of susceptibility and more specific periods of susceptibility (Faustman et al., 2000 ... 

---