BackgroundAlthough the exact pathophysiology of preeclampsia is not completely understood, the utility of different platelets indices can be utilized to predict preeclampsia.ObjectiveTo compare platelet indices, namely platelet count (PC), mean platelet volume (MPV), platelet distribution width (PDW), and PC to MPV ratio in women with preeclampsia compared with healthy controls.SettingQassim Hospital, Kingdom of Saudi Arabia.DesignA case–control study. Sixty preeclamptic women were the cases and an equal number of healthy pregnant women were the controls.ResultsThere was no significant difference in age, parity, and body mass index between the study groups. Sixteen and 44 of the cases were severe and mild preeclampsia, respectively. There was no significant difference in PDW and MPV between the preeclamptic and control women. Both PC and PC to MPV ratios were significantly lower in the women with preeclampsia compared with the controls. There was no significant difference in the PC, PDW, MPV, and PC to MPV ratio when women with mild and severe preeclampsia were compared. Using receiver operating characteristic (ROC) curves, the PC cutoff was 248.0×103/µL for diagnosis of pre-eclampsia (P=0.019; the area under the ROC curve was 62.4%). Binary regression suggests that women with PC <248.010×103/µL were at higher risk of preeclampsia (odds ratio =2.2, 95% confidence interval =1.08–4.6, P=0.03). The PC/MPV cutoff was 31.2 for diagnosis of preeclampsia (P=0.035, the area under the ROC curve was 62.2%).ConclusionPC <248.010×103/µL and PC to MPV ratio 31.2 are valid predictors of preeclampsia.

Simultaneous measurement of N2 O and CO2 flux at the soil surface with photoacoustic infrared spectroscopy (PAS) is gaining popularity due to portability, low maintenance, and ease-of-operation. However, the ability of PAS to measure N2 O with accuracy and precision similar to gas chromatography (GC) is uncertain due to overlap in N2 O, CO2 , and H2 O absorbance spectra combined with the large range in analyte concentrations. We tested the ability of six PAS units to simultaneously measure N2 O and CO2 gas concentrations and fluxes with accuracy and precision similar to two GC units. We also evaluated H2 O vapor and CO2 interferences with N2 O measurement. The accuracy and precision of standard gas concentration measurements with PAS and GC were similar. High water vapor (~26 600 ppm) and CO2 concentrations (~4500 ppm) did not interfere with N2 O measurement across the concentration range typically observed in static flux chambers at the soil surface (~0.5-3.0 ppm N2 O). On average, N2 O fluxes measured with the six PAS were 4.7% higher than one GC and 9.9% lower than the second GC.

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a b s t r a c tThe ability of biogeochemical ecosystem models to represent agro-ecosystems depends on their correct integration with field observations. We report simultaneous calibration of 67 DayCent model parameters using multiple observation types through inverse modeling using the PEST parameter estimation software. Parameter estimation reduced the total sum of weighted squared residuals by 56% and improved model fit to crop productivity, soil carbon, volumetric soil water content, soil temperature, N 2 O, and soil NO 3 À compared to the default simulation. Inverse modeling substantially reduced predictive model error relative to the default model for all model predictions, except for soil NO 3 À and NH 4 þ . Post-processing analyses provided insights into parametereobservation relationships based on parameter correlations, sensitivity and identifiability. Inverse modeling tools are shown to be a powerful way to systematize and accelerate the process of biogeochemical model interrogation, improving our understanding of model function and the underlying ecosystem biogeochemical processes that they represent.

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