Some measures of reducing leaching loss of nitrates beyond potential rooting zone

Summary Distribution of nitrates in soil profiles under eight different crop rotations was studied after the harvest of various constituent crops. Nitrate distribution patterns at different dates reveal that maximum leaching loss of nitrates occurs from rotations consisting of heavily fertilized shallow rooted crops like potato. Wheat and maize, in a rotation reduce nitrate leaching to deeper soil layers because of their deep and extensive rooting systems. In rainy season, when maximum movement of nitrates occurs in the profile, raising of deep rooted crops like maize leaves for leaching only a small amount of nitrates as compared to crops like groundnut and soybean with shallow rooting systems and low N-requirement. Summer season crops like moong, cowpeas and maize (fodder), do not alter nitrate distribution patterns, unless a large amount of nitrates is present in the profile prior to their sowing.Post-graduate student and Professor of Soils, respectivelyPost-graduate student and Professor of Soils, respectively     

Some measures of reducing leaching loss of nitrates beyond potential rooting zone

Summary Soil nitrate profiles under seven treatments of an experiment on intercropping in row crops were studied at sowing and the after harvesting of different crops. The estimates of NO₃ ^––N in these profiles indicate that intercropping in the row crops grown during the rainy season considerably reduced leaching loss of nitrates. Where the main crop receives the recommended fertilizer amount and the intercrop a small additional application, intercropping greatly reduced the amount of unutilized nitrates and hence their leaching beyong root zone.     

Some theoretical considerations relating to the meaning and measurement of chloroplast reducing potential

The meaning of “chloroplast reducing potential” is examined in order to find out whether determinations of it might not allow one to circumscribe possible mechanisms of photosynthesis. One can define a physical situation where a measure of “chloroplast reducing potential” could allow one to draw an important conclusion about the mechanism of photosynthesis. However, in order to achieve this, it is necessary to make very severe assumptions and to suppose that some very serious experimental difficulties can be overcome.     

Ghrelin as a potential blood pressure reducing factor in obese women during weight loss treatment

BACKGROUND: In animal models ghrelin reduces cardiac afterload and increases cardiac output via receptors in the cardiovascular system. The aim of our study was to evaluate a potential relationship between weight loss treatment, blood pressure and serum ghrelin concentrations in obese women. MATERIAL AND METHODS: A group of 37 obese premenopausal women with no previous history of hypertension (BMI: 36.5 +/- 5 kg/m2) were involved in the study. Blood pressure and serum ghrelin levels were assessed before and after a three-month weight reduction treatment, which consisted of a diet of 1000 kcal/day and physical exercise. Body composition was determined by impedance analysis using Bodystat. RESULTS: Following weight loss (mean 8.9 +/- 4.8 kg) SBP decreased (120 +/- 13 vs. 115 +/- 14 mm Hg, p = 0.01) and serum ghrelin levels increased significantly (66.9 +/- 13.7 vs. 73.9 +/- 15.4 pg/ml; p = 0.005). There were significant correlations between values for ghrelin levels after weight loss and SBP (r = -0.45, p = 0.02), DBP (r = -0.41, p < 0.05), and between Deltaghrelin levels and DeltaSBP (r = 0.52, p = 0.006), DeltaDBP (r = 0.53, p = 0.005). There was a positive correlation between an increase in ghrelin and a decrease in percentage body fat during weight loss (r = 0.51; p = 0.002). CONCLUSION: The results seem to provide evidence that weight loss may decrease blood pressure in obese patients via a ghrelin-dependent mechanism.     

A rapid method to evaluate potential vasodilatory activity of organic nitrates

The kinetics of interaction between organic nitrates (3,3-bis(nitroxymethyl)oxetane) and cysteine were evaluated by the rate of nitrite ion formation at various concentrations of reagents and pH. The activities of natural reducing agents, including cysteine, glutathione, and NADH, in generating the nitrite ion from organic nitrates (3,3-bis(nitroxymethyl)oxetane) were compared. Cysteine was shown to be the most potent reducing agent. Studying the effectiveness of nitrates (trinitroglycerol, 3,3-bis(nitroxymethyl)oxetane, and nicorandil) at a concentration of 3 mM showed that the rate of nitrite ion accumulation in the reaction with 10 mM cysteine is 1.66, 0.37, and 0.02 microM/min, respectively.     

A rapid method to evaluate potential vasodilatory activity of organic nitrates

The kinetics of interaction between organic nitrates (3,3-bis(nitroxymethyl)oxetane) and cysteine were evaluated by the rate of nitrite ion formation at various concentrations of reagents and pH. The activities of natural reducing agents, including cysteine, glutathione, and NADH, in generating the nitrite ion from organic nitrates (3,3-bis(nitroxymethyl)oxetane) were compared. Cysteine was shown to be the most potent reducing agent. Studying the effectiveness of nitrates (trinitroglycerol, 3,3-bis(nitroxymethyl)oxetane, and nicorandil) at a concentration of 3 mM showed that the rate of nitrite ion accumulation in the reaction with 10 mM cysteine is 1.66, 0.37, and 0.02 μM/min, respectively. The reaction of organic nitrate with cysteine (Cys) is used as a test system for analyzing the effectiveness of nitrates in nitrite ion formation, which correlates with vasodilatory activity of these compounds (dilation of blood vessels).     

Control of reversible intracellular transfer of reducing potential.

Isolated rat liver mitochondria were incubated in the presence of a reconstituted malate-aspartate shuttle under carboxylating conditions in the presence of glutamate, octanoyl-carnitine and pyruvate, or a preset lactate/pyruvate ratio. The respiration and attendant energy state were varied with soluble F1-ATPase. Under these conditions reducing equivalents are exported due to pyruvate carboxylation. This was shown by lactate production from pyruvate and by a substantial increase in the lactate/pyruvate ratio. This led to a competition between malate export and energy-driven malate cycling via the malate-aspartate shuttle, resulting in a lowered redox segregation of the NAD systems between the mitochondrial and extramitochondrial spaces. If pyruvate carboxylation was blocked, this egress of reducing equivalents was also blocked, leading to an elevated value of redox segregation, delta G(redox) (in kJ) = -5.7 log(NAD+/NADHout)/(NAD+/NADHin) being then equal to approximately one-half of the membrane potential, in accordance with electrogenic glutamate/aspartate exchange. Reconstitution of malate-pyruvate cycling led to a further kinetic decrease in the original malate-aspartate shuttle-driven value of delta G(redox). Therefore, the value of segregation of reducing potential between mitochondria and cytosol caused by glutamate/aspartate exchange can be diminished kinetically by processes exporting reducing equivalents from mitochondria, such as pyruvate carboxylation and pyruvate cycling.     

Effect of one year rotational set-aside on immediate and ensuing nitrogen leaching loss

This paper reports results from a 3-year field experiment which examined Nitrogen (N) leaching loss from land under various set-aside managements. Four treatments were examined: three ploughed plots which were sown with wheat, ryegrass or maintained fallow; the fourth treatment was unploughed and natural weed growth (volunteers) permitted. The l-year set-aside was followed by two winter wheat test crops. Ceramic suction cups were installed at a depth of 90 cm and used to collect drainage water. N leaching loss was calculated by multiplying drainage volume, calculated from meteorological data, by its inorganic N concentration.Set-aside management significantly affected N leaching loss over the three years. During the set-aside year, the peak nitrate concentration from the unploughed treatment growing volunteer weeds was significantly lower than that from ploughed plots. Of the latter, by the spring, crop (i.e. wheat and ryegrass) assimilation of N significantly reduced N concentration compared to the fallow. The four set-aside treatments had a carry-over effect to the following year (first wheat test crop) resulting in significant differences in N losses. Leaching following the ryegrass treatment was very small and we believe that the grass residues minimised rates of net-N mineralization.The influence of set-aside management continued to the second wheat test crop where N loss was greater under the all wheat rotation because take-all had reduced yield and therefore crop N uptake.     

Solid phase bioremediation of pendimethalin in contaminated soil and evaluation of leaching potential

Substrate leaching experiments were performed to study the relative leaching potential of pendimethalin in various types of soil matrices. Pendimethalin leaching showed up to a depth of 30 cm in all the studied soil matrices, irrespective of pH conditions used. The leaching potential of pendimethalin was assessed at various pH conditions. Comparatively higher leaching potential was observed in basic conditions compared to the neutral and acid conditions of soil. Soil phase bioremediation of pendimethalin was also performed on all the soil matrices. Among the studied variations, bioremediation experiments performed in presence of sunlight showed higher efficiency. Bioaugmentation along with sunlight showed higher remediation efficiency in all the studied soil matrices. Biostimulation did not respond positively on the progress of bioremediation.     

Homeostatic mechanisms and the loss of mitotic potential

A model for cell division in mammalian tissues is analyzed. The model treats cells capable of division and cells not so capable as separate populations. In the model homeostasis is achieved by a secretion of the non-dividers which acts upon newly formed cells to convert them into non-dividers. The principal result is given in the form of a theorem: if the rate at which cells divide exceeds the rate at which the non-dividers die, then the ratio of dividers to non-dividers tends to zero with time.     

Evaluation of enrichments of sulfate reducing bacteria from pristine hydrothermal vents sediments as potential inoculum for reducing trichloroethylene

The evaluation of enrichments from pristine hydrothermal vents sediments on its capability of reducing trichloroethylene (TCE) under sulfate reducing conditions with lactate and volatile fatty acids (VFAs) as substrates was performed. Effect of the possible TCE biodegradation intermediates cis and trans 1,2 dichloroethenes on sulfate reduction (SR) was also evaluated. The influence of cyanocobalamin (CNB₁₂) and riboflavin (RF) on the SR and biodegradation of TCE was also determined. Sediments from the vents were incubated at 37°C and supplemented with 4 g l⁻¹ SO₄ ²⁻, lactate or VFAs and amended in the corresponding treatments with either CNB₁₂ or RF in separated experiments. A percentage of TCE removal of 86 (150 μmol l⁻¹ initial concentration) was attained coupled to 48% sulfate depletion with lactate as substrate. Up to 93% removal of TCE (300 μmol l⁻¹ initial concentration) and 40% of sulfate was reached for VFAs as electron donor. A combination of lactate and CNB₁₂ yielded the best SR. The overall results suggest a syntrophic association in this microbial community in which sulfate reducers, dehalogenating, and probably halorespiring bacteria may be interacting and taking advantage of the fermentation of substrates differently, but without interruption of SR in spite of the fact that TCE was always present. It was also clear that sulfate reduction must be established in the cultures before any degradation can occur. The microbial community present in these hydrothermal vents sediments could be a new source of inoculum for bioreactors designed for dechlorination purposes.     

Some measures of information arising in statistical games

This paper discusses some measures of information which naturally arise in the context of statistical games (games against nature). Some useful inequalities are proven relating the entropy to the value of information provided by experiments. Two other measures, based on the notion of a metric as informational distance and that of a diameter value are also discussed.     

Assessment of nitrate leaching loss on a yield-scaled basis from maize and wheat cropping systems

Background and aims

It is so far a gap in knowledge to assess nitrate (NO₃ ^?) leaching loss linking with crop yield for a given cereal cropping system.

Methods

We conducted a meta-analysis on 32 published studies reporting both NO₃ ^? leaching losses and crop yields in the maize (N?=?20) and wheat (N?=?12) systems.

Results

On average, 22 % and 15 % of applied fertilizer N to wheat and maize systems worldwide are leached in the form of NO₃ ^?, respectively. The average area-scaled NO₃ ^- leaching loss for maize (57.4 kg N ha^?1) was approx. two times higher than for wheat (29.0 kg N ha^?1). While, if scaled to crop yields, the average yield-scaled NO₃ ^? losses were comparable between maize (5.40 kg N Mg^?1) and wheat (5.41 kg N Mg^?1) systems. Across all sites, the lowest yield-scaled NO₃ ^? leaching losses were observed at slightly suboptimal fertilization rates, corresponding to 90 % and 96 % of maximum maize or wheat yields, respectively.

Conclusions

Our findings suggest that small adjustments of agricultural N management practices can effectively reduce yield-scaled NO₃ ^? leaching losses. However, further targeted field experiments are still needed to identify at regional scale best agricultural management practices for reducing yield-scaled NO₃ ^? leaching losses in maize and wheat systems.     

Event-related potential measures of attention in moderately depressed subjects

Prior research has inferred attentional changes related to depression from evidence concerning other cognitive processes. The present experiment investigated attentional changes related to depression in a more direct manner. Subjects were 32 young adults attending college. Depression was measured by self-report measures. In an auditory selective attention task similar to that of Hansen and Hillyard (1980), auditory event-related potentials(ERPs) were recorded from central (Cz) and frontal (Fz) scalp locations. Evidence for selective attention was manifest as the difference wave (Nd), which showed larger mean and peak amplitudes for the less difficult of two attention conditions. Nd was also shown to have an earlier peak latency at the Cz scalp location. However, there was no significant difference between the Depressed and Control groups as measured by the Nd wave. Significant differences were found between groups for the amplitude of the N1 peak of the ERP at the Fz scalp location. This suggests that the Depressed group differed in arousal level or sensory sensitivity from the Control group.     

A legion of potential regulatory sRNAs exists beyond the typical microRNAs microcosm

Post ENCODE, regulatory sRNAs (rsRNAs) like miRNAs have established their status as one of the core regulatory elements of cell systems. However, large number of rsRNAs are compromised due to traditional approaches to identify miRNAs, limiting the otherwise vast world of rsRNAs mainly to hair-pin loop bred typical miRNAs. The present study has analyzed for the first time a huge volume of sequencing data from 4997 individuals and 25 cancer types to report 11 234 potentially regulatory small RNAs which appear to have deep reaching impact. The rsRNA-target interactions have been studied and validated extensively using experimental data from AGO-crosslinking, DGCR8 knockdown, CLASH, proteome and expression data. A subset of such interactions was also validated independently in the present study using multiple cell lines, by qPCR. Several of the potential rsRNAs have emerged as a critical cancer biomarker controlling some important spots of cell system. The entire study has been presented into an interactive info-analysis portal handling more than 260 GB of processed data. The possible degree of cell system regulation by sRNAs appears to be much higher than previously assumed.     

Influence of rocks on soil temperature,soil water potential,and rooting patterns for desert succulents

Summary At a site in the Sonoran Desert, subterranean rocks and exposed boulders affected soil water potential as well as root morphology and distribution. For Agave deserti, the number of lateral roots per unit length of main root was 11 times higher under rocks and six times higher alongside rocks than in rock-free regions. Total root length per unit soil volume for Echinocereus engelmannii averaged 3-fold higher within 1 cm of boulders than 5 cm away, where the soil was drier. The total length of lateral roots per unit length of main root for Ferocactus acanthodes was 4.2 m m^–1 under rocks but only 0.8 m m^–1 in rock-free regions. The number of lateral roots per unit length of main root for Opuntia acanthocarpa was 7-fold higher alongside rocks than in rock-free regions and even higher under rocks. For transplanted and watered A. deserti, the number of new main roots produced per 1–2 month interval averaged 13 for five plants on the north side of boulders, 8 on the south side, 11 for five plants with half of their roots under rocks, 2 for those with half of their roots over rocks, and 3 for the control plants without rocks. Laboratory experiments showed that the soil water potential under rocks for 10 and 30 mm waterings stayed above –0.5 MPa for 13 and 19 d longer, respectively, than for regions away from rocks. The shortwave absorptance of granitic rocks from the field site was 0.82, the thermal conductivity coefficient was 1.50 W m^–1 °C^–1, and the volumetric heat capacity was 1.75 MJ m^–3 °C^–1. Field measurements indicated that 5-cm-thick buried rocks decreased the diel variation in soil temperatures on their undersurface by only 0.4° C compared with soil. Thus, the primary influence of rocks at the field site on root proliferation and branching for the four species was apparently caused by influences on soil water content.