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Accurate estimation of plant height is essential for precision crop production. Remote sensing provides a beneficial tool for monitoring plant height, but few attempts had been made to monitor wheat plant height using ground-based hyperspectral vegetation indexes. This study systematically analyzed the quantitative relationship between various hyperspectral vegetation indexes and wheat plant height based on a field experiment under different sowing conditions (i.e., normal sowing and late sowing). The optimal vegetation indexes that were highly sensitive to wheat plant height were derived by comparing the newly constructed hyperspectral vegetation indexes with published vegetation indexes. The experiment was conducted at the Agrometeorological Station, Nanjing University of Information Science and Technology, Jiangsu Province, China. Wheat canopy reflectance spectra were synchronously determined with plant height in tillering-anthanis stage. Results showed that the newly developed vegetation index (R785 – R810)/(R785 + R810 – 2×R802) in normal sowing treatment and R1029 – R1004 in late sowing treatment, generated the optimal testing performance for estimating wheat plant height with the coefficient of determination (R2) of 0.78 and 0.89, root mean square error (RMSE) of 7.37 and 5.92 cm, and residual prediction deviation (RPD) of 2.04 and 3.09, respectively. This study suggests that the ground-based hyperspectral remote sensing technique can provide spectral indexes for accurately monitoring wheat plant height. [ABSTRACT FROM AUTHOR]

Background: The use of hypertonic crystalloid solutions, including sodium chloride and bicarbonate, for treating severe sepsis has been much debated in previous investigations. We have investigated the effects of three crystalloid solutions on fluid resuscitation in severe sepsis patients with hypotension. Methods: Ninety-four severe sepsis patients with hypotension were randomly assigned to three groups. The patients received the following injections within 15 min at initial treatment: Ns group (n = 32), 5 ml/kg normal saline; Hs group (n = 30), with 5 ml/kg 3.5% sodium chloride; and Sb group (n = 32), 5 ml/kg 5% sodium bicarbonate. Cardiac output (CO), systolic blood pressure, mean arterial pressure (MAP), body temperature, heart rate, respiratory rate and blood gases were measured. Results: There were no differences among the three groups in CO, MAP, heart rate or respiratory rate during the 120 min trial or the 8 hour follow-up, and no significant differences in observed mortality rate after 28 days. However, improvement of MAP and CO started earlier in the Sb group than in the Ns and Hs groups. Sodium bicarbonate increased the base excess but did not alter blood pH, lactic acid or [HCO3]- values; and neither 3.5% hypertonic saline nor 5% sodium bicarbonate altered the Na+, K+, Ca2+ or Cl- levels. Conclusion: All three crystalloid solutions may be used for initial volume loading in severe sepsis, and sodium bicarbonate confers a limited benefit on humans with severe sepsis. Trial registration: ISRCTN36748319. [ABSTRACT FROM AUTHOR]