Water deficit calculation

Add 1.6 mEq/L to the measured serum sodium for every 100 mg/dL rise in serum glucose >200 mg/dL ° Calculate free water deficit... 

Calculating water deficit and general management principles... 

Calculate the water deficit in a 75-kg male with a serum sodium of 154 mEq/L (154 mmol/L). 

Nearly all quantitative estimates of open-ocean water column denitrification are based on some type of nitrate deficit calculation. In the Arabian Sea, Naqvi (1987) have used nutrient-potential temperature relationships to estimate a denitrification rate of 30 Tg/y. In a later study Naqvi and Shailaja (1993) arrived at a... 

Figure 2. The KBIs and excesses (or deficits) for methanol (l)/water (2) mixtures (T = 313.15 K). (a) The KBIs" Gn (A), G22 (B), and Gn(C) (b) excesses (or deficits) around a central methanol molecule calculated with eq 1 (c) excesses (or deficits) around a central water molecule calculated with eq 1 (2) excesses (or deficits) around a central methanol molecule calculated with eq 13 (e) excesses (or deficits) around a central water molecule calculated with eq 13.

It is clear (see Figures 1—3) that the excesses (or deficits) calculated with the new eq 13 are always very different from those obtained with eq 1. However, eq 13 and eqs 3 and 4 provide comparable results for binary mixtures when the molar volumes of the components are approximately the same. The results obtained using eq 1 and those obtained from eq 13 for methanoFwater and 2-propanoFwater mixtures are very different. In contrast to the methods based on a reference state, the new method predicts that the alcohols are preferentially hydrated at high alcohol mole fractions. For the 2-propanol/water mixtures there are experimental observations which support this prediction. 

Let us apply eqns (13), (14) and (15) to a real system and compare the results. Fig. 2 provides such a comparison for the binary system isopropanol (l)-water (2) (The Kirkwood-Buff integrals were taken from literature and the van der Waals volumes were calculated as suggested in ref. 39-41). Fig. 2 shows that the excesses (deficits) calculated using all three equations (eqns (13), (14) and (15)) provide quite comparable results for both central isopropanol and water molecules. The differences between the excesses (deficits) calculated with eqns (13) and (14) are small. 

However, only 401 of water is available from the first concentration interval. This implies that the deficit should be supplied by fresh water. The amount of fresh water required is calculated as ... 

Caicuiation of sodium deficit-To calculate the amount of sodium that must be administered to raise serum sodium to the desired level, use the following equation (TBW = total body water) Na deficit (mEq) = TBW (desired - observed plasma Na). 

Initial dose - 1 to 2 mEq/kg/min given over 1 to 2 minutes followed by 1 mEq/kg every 10 minutes of arrest. If base deficit is known, give calculated dose of 0.3 X kg X base deficit. If only 7.5% or 8.4% sodium bicarbonate is available, dilute 1 1 with 5% dextrose in water before administration. 

The commonly used expression Vapor Pressure Deficit or VPD is the partial pressure of water vapor in the leaf intercellular air spaces, minus the partial pressure of water vapor in the turbulent air outside the boundary layer, P 0,. Often P af is calculated as the saturation water vapor partial pressure at the temperature of the leaf (for a leaf water potential of -1.4 MPa at 20°C, this leads to an error of only 1% in Pj. af Table 2-1). P a, equals the air relative humidity times the saturation water vapor partial pressure (P. w) at the air temperature (values of P , in kPa, which can be used to calculate P f and P 0, are given at the end of Appendix I). 

The first quantitative estimates of denitrification in the eastern tropical North Pacific were made by Codispoti and Richards (1976). Codispoti and Richards used apparent oxygen utilization, AOU, and phosphate data to stoichiometricaUy extrapolate back to the nitrate concentration present when a given water mass was previously at the surface. In this way they were able to develop a relationship between pNOj and sigma-f for waters of the ETNP-ODZ, from which they calculated nitrate deficit as outlined in Eq. (6.4). 

A second method used to calculate nitrate deficit takes advantage of the semiconservative water-mass tracer NO (Broecker, 1974). StoichiometricaUy, every mole of O2 respired wiU remineralize approximately 1/9 of a mole of NOJ so that NO, defined as... 

Figure 6.16 Solutions to a horizontal ventilation model of denitrification for waters of the eastern tropical North Pacific for d NOa vs J, the fraction of nitrate remaining, i.e., the measured nitrate minus the nitrate deficit. Nitrate deficit was calculated as NOa deficit) = M.8 x PO4—NO3, where NO3 and PO4 are the measured concentrations.The two equations describing the steady-state nitrate isotope distrihution are 0[ NO3]/0t—J[ N03] + 0 [ NO3]/0a and0[ NO3]/0t—aQ/[ N03] + ri0 pNO3]/0x where is the eddy diffusion coefficient in the x direction, J is the denitrification rate, a is the fraction factor, and Q is a N N ratio that makes the system non-linear. (See Voss et at, 2001 for solution details). Solutions for three different values of are given ( = [l-0(] x 1000).

Using the expressions suggested in this paper, we calculated the excess number of molecules An ij around a central one (eqs 22—24). Figure 10 provides the excess (or deficit) number of molecules in the vicinity of an alcohol molecule and Figure 11—in the vicinity of a water molecule as the central molecule. 

The present paper is devoted to the local composition of liquid mixtures calculated in the framework of the Kirkwood—Buff theory of solutions. A new method is suggested to calculate the excess (or deficit) number of various molecules around a selected (central) molecule in binary and multicomponent liquid mixtures in terms of measurable macroscopic thermodynamic quantities, such as the derivatives of the chemical potentials with respect to concentrations, the isothermal compressibility, and the partial molar volumes. This method accounts for an inaccessible volume due to the presence of a central molecule and is applied to binary and ternary mixtures. For the ideal binary mixture it is shown that because of the difference in the volumes of the pure components there is an excess (or deficit) number of different molecules around a central molecule. The excess (or deficit) becomes zero when the components of the ideal binary mixture have the same volume. The new method is also applied to methanol + water and 2-propanol -I- water mixtures. In the case of the 2-propanol + water mixture, the new method, in contrast to the other ones, indicates that clusters dominated by 2-propanol disappear at high alcohol mole fractions, in agreement with experimental observations. Finally, it is shown that the application of the new procedure to the ternary mixture water/protein/cosolvent at infinite dilution of the protein led to almost the same results as the methods involving a reference state. 

Therefore, for the system water (l)/protein (2)/cosolvent (or salt) (3), the new method for calculating the excesses (or deficits) around a biomolecule at its infinite dilution (eq 13) leads to the same results as those based on a reference state (eqs 3 and 4). The method based on eq 1 leads to erroneous results because it does not reflect the true excesses (deficits) of water and cosolvent around an infinitely dilute biomolecule. 

The KBIs for the 1-propanol (l)/water (2) mixture are available in the literature,and there is agreement between the KBIs obtained in various calculations.In the present paper, the excesses (deficits) for the 1-propanol (l)/water (2) mixture have been calculated with eqn (13) by using the KBIs already calculated by us. The partial molar volumes for the 1-propanol (l)/water (2) mixture have been calculated from density data" and the isothermal compressibilities have been evaluated using the expression ... 

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