Tropical Peatland Hydrology Simulated With a Global Land Surface Model.

Tropical peatlands are among the most carbon-dense ecosystems on Earth, and their water storage dynamics strongly control these carbon stocks. The hydrological functioning of tropical peatlands differs from that of northern peatlands, which has not yet been accounted for in global land surface models (LSMs). Here, we integrated tropical peat-specific hydrology modules into a global LSM for the first time, by utilizing the peatland-specific model structure adaptation (PEATCLSM) of the NASA Catchment Land Surface Model (CLSM). We developed literature-based parameter sets for natural (PEATCLSMTrop,Nat) and drained (PEATCLSMTrop,Drain) tropical peatlands. Simulations with PEATCLSMTrop,Nat were compared against those with the default CLSM version and the northern version of PEATCLSM (PEATCLSMNorth,Nat) with tropical vegetation input. All simulations were forced with global meteorological reanalysis input data for the major tropical peatland regions in Central and South America, the Congo Basin, and Southeast Asia. The evaluation against a unique and extensive data set of in situ water level and eddy covariance-derived evapotranspiration showed an overall improvement in bias and correlation compared to the default CLSM version. Over Southeast Asia, an additional simulation with PEATCLSMTrop,Drain was run to address the large fraction of drained tropical peatlands in this region. PEATCLSMTrop,Drain outperformed CLSM, PEATCLSMNorth,Nat, and PEATCLSMTrop,Nat over drained sites. Despite the overall improvements of PEATCLSMTrop,Nat over CLSM, there are strong differences in performance between the three study regions. We attribute these performance differences to regional differences in accuracy of meteorological forcing data, and differences in peatland hydrologic response that are not yet captured by our model.

PEAT-CLSM: A Specific Treatment of Peatland Hydrology in the NASA Catchment Land Surface Model.

Peatlands are poorly represented in global Earth system modeling frameworks. Here we add a peatland-specific land surface hydrology module (PEAT-CLSM) to the Catchment Land Surface Model (CLSM) of the NASA Goddard Earth Observing System (GEOS) framework. The amended TOPMODEL approach of the original CLSM that uses topography characteristics to model catchment processes is discarded, and a peatland-specific model concept is realized in its place. To facilitate its utilization in operational GEOS efforts, PEAT-CLSM uses the basic structure of CLSM and the same global input data. Parameters used in PEAT-CLSM are based on literature data. A suite of CLSM and PEAT-CLSM simulations for peatland areas between 40°N and 75°N is presented and evaluated against a newly compiled data set of groundwater table depth and eddy covariance observations of latent and sensible heat fluxes in natural and seminatural peatlands. CLSM's simulated groundwater tables are too deep and variable, whereas PEAT-CLSM simulates a mean groundwater table depth of -0.20 m (snow-free unfrozen period) with moderate temporal fluctuations (standard deviation of 0.10 m), in significantly better agreement with in situ observations. Relative to an operational CLSM version that simply includes peat as a soil class, the temporal correlation coefficient is increased on average by 0.16 and reaches 0.64 for bogs and 0.66 for fens when driven with global atmospheric forcing data. In PEAT-CLSM, runoff is increased on average by 38% and evapotranspiration is reduced by 19%. The evapotranspiration reduction constitutes a significant improvement relative to eddy covariance measurements.

Effect of past peat cultivation practices on present dynamics of dissolved organic carbon.

Peatlands are a major source of dissolved organic carbon (DOC) for aquatic ecosystems. Naturally high DOC concentrations in peatlands may be increased further by drainage. For agricultural purposes, peat has frequently been mixed with sand, but the effect of this measure on the release and cycling of DOC has rarely been investigated. This study examined the effects of (i) mixing peat with sand and (ii) water table depth (WTD) on DOC concentrations at three grassland sites on shallow organic soils. The soil solution was sampled bi-weekly for two years with suction plates at 15, 30 and 60cm depth. Selected samples were analysed for dissolved organic nitrogen (DON), δ13CDOM and δ15NDOM. Average DOC concentrations were surprisingly high, ranging from 161 to 192mgl-1. There was no significant impact of soil organic carbon (SOC) content or WTD on mean DOC concentrations. At all sites, DOC concentrations were highest at the boundary between the SOC-rich horizon and the mineral subsoil. In contrast to the mean concentrations, the temporal patterns of DOC concentrations, their drivers and the properties of dissolved organic matter (DOM) differed between peat-sand mixtures and peat. DOC concentrations responded to changes in environmental conditions, but only after a lag period of a few weeks. At the sites with a peat-sand mixture, temperature and therefore probably biological activity determined the DOC concentrations. At the peat site, the contribution of vegetation-derived DOM was higher. The highest concentrations occurred during long, cool periods of waterlogging, suggesting a stronger physicochemical-based DOC mobilisation. Overall, these results indicate that mixing peat with sand does not improve water quality and may result in DOC losses of around 200kg DOCha-1a-1.

Multi-objective optimization for the economic production of d-psicose using simulated moving bed chromatography.

The biocatalytic production of rare carbohydrates from available sugar sources rapidly gains interest as a route to acquire industrial amounts of rare sugars for food and fine chemical applications. Here we present a multi-objective optimization procedure for a simulated moving bed (SMB) process for the production of the rare sugar d-psicose from enzymatically produced mixtures with its epimer d-fructose. First, model parameters were determined using the inverse method and experimentally validated on a 2-2-2-2 lab-scale SMB plant. The obtained experimental purities (PUs) were in excellent agreement with the simulated data derived from a transport-dispersive true-moving bed model demonstrating the feasibility of the proposed design. In the second part the performance of the separation was investigated in a multi-objective optimization study addressing the cost-contributing performance parameters productivity (PR) and desorbent requirement (DR) as a function of temperature. While rare sugar SMB operation under conditions of low desorbent consumption was found to be widely unaffected by temperature, SMB operation focusing on increased PR significantly benefited from high temperatures, with possible productivities increasing from 3.4kg(Lday)(-1) at 20°C to 5kg(Lday)(-1) at 70°C, indicating that decreased selectivity at higher temperatures could be fully compensated for by the higher mass transfer rates, as they translate into reduced switch times and hence higher PR. A DR/PR Pareto optimization suggested a similar but even more pronounced trend also under relaxed PU requirements, with the PR increasing from 4.3kg(Lday)(-1) to a maximum of 7.8kg(Lday)(-1) for SMB operation at 50°C when the PU of the non-product stream was reduced from 99.5% to 90%. Based on the in silico optimization results experimental SMB runs were performed yielding considerable PRs of 1.9 (30°C), 2.4 (50°C) and 2.6kg(Lday)(-1) (70°C) with rather low DR (27L per kg of rare sugar produced) on a lab-scale SMB installation.

Methylphenidate and if-then plans are comparable in modulating the P300 and increasing response inhibition in children with ADHD.

A disturbed functioning of the prefrontal cortex, the anterior cingulate cortex, and an accordingly reduced P300 presumably underlies executive function deficits of children with attention deficit hyperactivity disorder (ADHD). Using a combined classification and Go/NoGo task paradigm, the present study investigated whether medication with methylphenidate (MPH) modulates the P300 as measured by a high-density electroencephalogram (EEG) and facilitates response inhibition in children with ADHD. Further, effects of MPH were compared with effects of self-regulation by if-then plans (Gollwitzer in Am Psychol 54: 493-503, 1999). MPH as well as if-then plans modulated the P300 and improved inhibition of an unwanted response on a Go/NoGo task to the same level observed in children without ADHD. Importantly, self-regulation strategies might be a valuable alternative to medication with MPH in children with ADHD.

Educational quality improvement report: outcomes from a revised morbidity and mortality format that emphasised patient safety.

PROBLEM: Although Morbidity and Mortality conferences (MMC) were originally designed to promote quality care through careful analysis of adverse events, focus on individual actions or the fear of incrimination may interfere with identification of system issues contributing to the adverse outcomes. DESIGN: Pre- and post-intervention assessments of participant attitudes toward patient safety and conference redesign were performed utilizing an attitudinal survey. Participants provided a unique identifier for paired-means procedure. A list of contributing factors, recommended solutions, and targeted system improvements was maintained with ongoing progress recorded. SETTING: Department of Internal Medicine training program at University of Missouri-Columbia, an academic health care center affiliated with the University of Missouri Hospitals and Clinics and the Harry S. Truman Veteran's Administration Hospital. PARTICIPANTS: Residents and fellows from the Department of Internal Medicine residency program. EDUCATIONAL OBJECTIVES: (1) Distinguish between culture of blame/shame and patient safety culture, (2) Identify gaps in quality contributing to adverse outcomes, (3) Identify strategies to close gaps, (4) Participate in root cause analysis, demonstrating an ability to review an adverse event and recommend an action plan. STRATEGIES FOR CHANGE: An interdisciplinary team modified the internal medicine MMC to emphasize a better understanding of patient safety principles and system-based practice interventions. For each adverse event analyzed, root causes were identified, followed by discussion of system interventions that might prevent future such events. KEY MEASURES FOR IMPROVEMENT: (1) Attitudes of residents and fellows regarding patient safety, as measured on a 20 item, five-point ordinal scale (strongly disagree to strongly agree) survey, (2) System improvements generated from the Patient Safety M&M Conferences (PSMMC), and (3) Attendance at PSMMC. EFFECTS OF CHANGE: Clinical outcomes: Conference participants offered 121 system improvement recommendations; 39 suggested system interventions were pursued based upon the likelihood of achieving high impact changes. These targeted changes were assigned to department/facility representatives with 23 (59%) improvements implemented, 11 (28%) partially implemented or in progress, and five (13%) abandoned due to impracticality or redundancy. Educational outcomes: Surveys were completed by 58 residents and fellows before and after modification of conference format. Six of the 20 survey items showed significant change with four of these changes occurring in the desired direction. Eleven of the remaining 14 responses changed in the desired direction, but did not reach statistical significance. Average MMC attendance increased from 41+/-8 to 50+/-10 (p<0.03) participants. LESSONS LEARNT: The new PSMMC initiated multiple improvements in the quality of patient care without sacrificing attendance or attitudes of the residents or fellows. The new PSMMC promotes opportunities for participants to improve quality of patient care in a safe and nurturing environment.

Educational quality improvement report: outcomes from a revised morbidity and mortality format that emphasised patient safety.

PROBLEM: Although morbidity and mortality conferences (MMCs) are meant to promote quality care through careful analysis of adverse events, focus on individual actions or the fear of incrimination may interfere with identification of system issues contributing to the adverse outcomes. DESIGN: Participant attitudes before and after the intervention towards patient safety and conference redesign were assessed using an attitudinal survey. A list of contributing factors, recommended solutions and targeted system improvements was maintained with ongoing progress recorded. SETTING: Department of Internal Medicine training programme at University of Missouri-Columbia. PARTICIPANTS: Residents and fellows from the above residency programme. EDUCATIONAL OBJECTIVES: (1) Distinguish between culture of blame/shame and patient safety culture, (2) identify gaps in quality contributing to adverse outcomes (3) identify strategies to close gaps and (4) participate in root cause analysis, demonstrating an ability to review an adverse event and recommend an action plan. STRATEGIES FOR CHANGE: An interdisciplinary team modified the internal medicine MMC to emphasise a better understanding of patient safety principles and system-based practice interventions. For each adverse event analysed, root causes were identified, followed by discussion of system interventions that might prevent future such events. KEY MEASURES FOR IMPROVEMENT: (1) Attitudes of residents and fellows regarding patient safety, as measured on a 20-item, five-point ordinal scale survey, (2) system improvements generated from the patient safety MMC (PSMMC) and (3) attendance at PSMMC. EFFECTS OF CHANGE: Clinical outcomes: 121 system improvement recommendations were made and 39 were pursued on the basis of likelihood of achieving high impact changes. 23 improvements were implemented, 11 were partially implemented or in progress, and 5 were abandoned due to impracticality or redundancy. Educational outcomes: 58 residents and fellows completed surveys before and after modification of conference format. 6/20 survey items showed substantial change with four of these changes occurring in the desired direction. Eleven of the remaining 14 responses changed in the desired direction. Average MMC attendance increased from 41+/-8 to 50+/-10 participants (p<0.03). LESSONS LEARNT: The new PSMMC initiated multiple improvements in the quality of patient care without sacrificing attendance or attitudes of the residents or fellows. The new PSMMC promotes opportunities for participants to improve quality of patient care in a safe and nurturing environment.

Model-based characterization of an amino acid racemase from Pseudomonas putida DSM 3263 for application in medium-constrained continuous processes.

The amino acid racemase with broad substrate specificity from Pseudomonas putida DSM 3263 was overproduced and characterized with respect to application in an integrated multi-step process (e.g., dynamic kinetic resolution) that--theoretically--would allow for 100% chemical yield and 100% enantiomeric excess. Overexpression of the racemase gene in Escherichia coli delivered cell free extract with easily sufficient activity (20-50 U mg(-1) total protein) for application in an enzyme membrane reactor (EMR) setting. Model-based experimental analysis of a set of enzyme assays clearly indicated that racemization of the model substrates D- or L-methionine could be accurately described by reversible Michaelis-Menten kinetics. The corresponding kinetic parameters were determined from progress curves for the entire suitable set of aqueous-organic mixtures (up to 60% methanol and 40% acetonitrile) that are eligible for an integrated process scheme. The resulting kinetic expression could be successfully applied to describe enzyme membrane reactor performance under a large variety of settings. Model-based calculations suggested that a methanol content of 10% and an acetonitrile content of 20% provide maximum productivity in EMR operations. However product concentrations were decreased in comparison to purely aqueous operation due to decreasing solubility of methionine with increasing organic solvent content. Finally, biocatalyst stability was investigated in different solvent compositions following a model-based approach. Buffer without organic content provided excellent stability at moderate temperatures (20-35 degrees C) while addition of 20% acetonitrile or methanol drastically reduced the half-life of the racemase.

Fetomaternal Doppler sonography nomograms.

PURPOSE: To constitute Doppler flow velocity nomograms for use in obstetric clinics and to analyse the technical infrastructure of constructing Doppler sonography nomograms for clinical use. METHODS: On a cross-sectional study plan basis 602 flow results of 370 pregnant women were used. Pregnancy gestational ages were confirmed with an early sonogram prior to the 14th gestational week. Patients in whom primary section for placental insufficiency had to be done, who had pathological fetal heart rate monitoring, signs of intrauterine asphyxia, multiple pregnancy or a fetal anomaly were excluded. Every two gestational weeks patients were grouped and for these groups the 5th, 10th, 50th, 90th and 95th percentiles were calculated to represent the umbilical artery, fetal aorta, middle cerebral artery (MCA) and uterine artery S/D ratio, resistence index (RI) and pulsatility index (PI) Doppler flow velocity nomograms. RESULTS: In normal pregnancies, after the 22nd-24th gestational week, the uteroplacental flow velocities were constant, but at the fetal vessels there were changes in velocity waveforms after this period. With advancing gestation in the third trimester, umbilical artery and middle cerebral artery impedance was lower and the resistance in the descending fetal aorta remained nearly constant. CONCLUSION: With growing gestational age the Doppler velocity forms change. In fact because of this, for Doppler velocity studies and to differentiate between normal and abnormal pregnancy status, nomograms adapted to gestational age should be used. For practical use in different obstetrics clinics, we are presenting our Doppler velocity norm-curves.

Structure of the P700(+ )A1(-) radical pair intermediate in photosystem I by high time resolution multifrequency electron paramagnetic resonance: analysis of quantum beat oscillations.

The geometry of the secondary radical pair P700(+)A1(-), in photosystem I (PSI) from the deuterated and 15N-substituted cyanobacterium Synechococcus lividus, has been determined by high time resolution electron paramagnetic resonance (EPR), performed at three different microwave frequencies. Structural information is extracted from light-induced quantum beats observed in the transverse magnetization of P700(+)A1(-) at early times after laser excitation. A computer analysis of the two-dimensional Q-band experiment provides the orientation of the various magnetic tensors of with respect to a magnetic reference frame. The orientation of the cofactors of the primary donor in the g-tensor system of is then evaluated by analyzing time-dependent X-band EPR spectra, extracted from a two-dimensional data set. Finally, the cofactor arrangement of P700(+)A1(-) in the photosynthetic membrane is deduced from angular-dependent W-band spectra, observed for a magnetically aligned sample. Thus, the orientation of the g-tensor of P700(+) with respect to a chlorophyll based reference system could be determined. The angle between the g1(z) axis and the chlorophyll plane normal is found to be 29 +/- 7 degrees, while the g1(y) axis lies in the chlorophyll plane. In addition, a complete structural model for the reduced quinone acceptor, A1(-), is evaluated. In this model, the quinone plane of is found to be inclined by 68 +/- 7 degrees relative to the membrane plane, while the P700(+)-A1(-) axis makes an angle of 35 +/- 6 degrees with the membrane normal. All of these values refer to the charge separated state, observed at low temperatures, where forward electron transfer to the iron-sulfur centers is partially blocked. Preliminary room temperature studies of P700(+)A1(-), employing X-band quantum beat oscillations, indicate a different orientation of A1(-) in its binding pocket. A comparison with crystallographic data provides information on the electron-transfer pathway in PSI. It appears that quantum beats represent excellent structural probes for the short-lived intermediates in the primary energy conversion steps of photosynthesis.

Evidence for oxidative damage to red blood cells in mice induced by arsine gas.

In animals and human beings exposed to arsine gas (AsH3) a severe and fulminant lysis of erythrocytes occurs. Little is known about the effects of subchronic exposure on the hematopoietic system or about the mechanism of hemolysis produced by arsine gas. To examine these, we exposed male and female mice to 0.000, 0.025, 0.500 and 2.500 ppm arsine gas for 6 h a day, 5 days a week during a 90-day period. After 5, 15, and 90 days of exposure, blood was collected and routine hematologic profiles were performed to document the effects of arsine gas on peripheral blood. A moderate hemolytic anemia, indicated by decreases in erythrocyte counts, hematocrits, hemoglobin concentrations and increases in mean corpuscular hemoglobins and mean corpuscular hemoglobin concentrations, was seen in blood samples collected after 5 days of exposure. In blood collected after 15 and 90 days of exposure, the anemia was less severe but a greater increase in mean corpuscular volumes and absolute reticulocyte counts revealed an active regenerative response. Higher concentrations of methemoglobin in animals in the 2.500 ppm exposure group (measured after 90 days of exposure) indicated that the rate of oxidation of heme (ferrous to ferric) increased due to exposure to arsine gas. Additionally, the presence of Heinz bodies in blood smears stained with brilliant cresyl blue and decreases in reduced glutathione concentrations in red blood cells exposed to arsine gas in vitro provide evidence that the mechanism of hemolysis involves depletion of intracellular reduced glutathione resulting in an oxidation of sulfhydryl groups in hemoglobin and possibly red cell membranes.

Carbon tetrachloride-mediated expiration of pentane and chloroform by the intact rat: the effects of pretreatment with diethyl maleate, SKF-525A and phenobarbital.

Measurements were made of pentane, a produce of lipid peroxidation, and chloroform (CHCl3), a product of the reproductive metabolism of carbon tetrachloride (CCl4), expired by rats administered CCl4 plus either phenobarbital (PB), 2-diethylaminoethyl-2,2-diphenyl valerate hydrochloride (SKF-525A), or diethyl maleate (DEM). In rats fed a standard laboratory diet, treatment with PB prior to injection of CCl4 increased expiration of both CHCl3 and pentane. SKF-525A pretreatment decreased the metabolism of CCl4 and CCl4-induced lipid peroxidation. DEM, a depleter of intracellular glutathione, increased lipid peroxidation. In rats fed 10% corn oil diets that contained either 0 or 40 IU of dl-alpha-tocopherol acetate, oxidant stresses caused by glutathione depletion and CCl4-intoxication were found to be additive.

Carbon tetrachloride-induced lipid peroxidation: simultaneous in vivo measurements of pentane and chloroform exhaled by the rat.

Simultaneous measurements of pentane, an index of lipid peroxidation, and chloroform (CHCl3), an index of carbon tetrachloride (CCl4) metabolism, were made on samples of breath from rats injected with 30 microliter CCL4/100 g body wt. In the first 3 h after administration of CCl4, rats fasted overnight metabolized less CCl4 and exhaled less pentane than did fed rats. Multiple injections of CCl4 decreased both the metabolism of CCl4 to CHCl3 and the level of in vivo lipid peroxidation following administration of a subsequent dose of CCl4. Dietary vitamin E provided limited protection from CCl4-induced lipid peroxidation and had no effect on the rate of CCl4 metabolism to CHCl3.