Irrigation and drainage in the new millennium

Presented at the 2000 USCID international conference, Challenges facing irrigation and drainage in the new millennium on June 20-24 in Fort Collins, Colorado.Includes bibliographical references.Current global population growth rates require an increase in agricultural food production of about 40-50% over the next thirty to forty years, in order to maintain present levels of food intake. To meet the target, irrigated agriculture must play a vital role, in fact the FAO estimates that 60% of future gains will have to come from irrigation. The practice of controlling drainage involves the extension of on-farm water management to include drainage management. With the integration of irrigation and drainage management, the water balance can be managed to reduce excess water losses and increase irrigation efficiencies. Controlled drainage is relatively new and there are many theoretical and practical issues to be addressed. The technique involves maintaining high water table in the soil profile for extended periods of time, requiring careful management to ensure that crop growth is not affected by anaerobic conditions. A fieldwork programme has been investigated to test controlled drainage in the Nile Delta, where water resources are stretched to the limit. Water saving is essential in the next 20 years. Pressures from the fixed Nile water allocation, population growth, industry and other sectors and the horizontal expansion programme mean that this need is urgent. One crop season has been completed at a site in the Western Nile Delta using simple control devices in the subsurface drainage system. This paper discusses the potential benefits of controlled drainage to save water in agricultural areas such as the Nile Delta, and presents findings from the first crop season

Faster N release, but not C loss, from leaf litter of invasives compared to native species in mediterranean ecosystems

Plant invasions can have relevant impacts on biogeochemical cycles, whose extent, in Mediterranean ecosystems, have not yet been systematically assessed comparing litter carbon (C) and nitrogen (N) dynamics between invasive plants and native communities. We carried out a 1-year litterbag experiment in 4 different plant communities (grassland, sand dune, riparian and mixed forests) on 8 invasives and 24 autochthonous plant species, used as control. Plant litter was characterized for mass loss, N release, proximate lignin and litter chemistry by 13C CPMAS NMR. Native and invasive species showed significant differences in litter chemical traits, with invaders generally showing higher N concentration and lower lignin/N ratio. Mass loss data revealed no consistent differences between native and invasive species, although some woody and vine invaders showed exceptionally high decomposition rate. In contrast, N release rate from litter was faster for invasive plants compared to native species. N concentration, lignin content and relative abundance of methoxyl and N-alkyl C region from 13C CPMAS NMR spectra were the parameters that better explained mass loss and N mineralization rates. Our findings demonstrate that during litter decomposition invasive species litter has no different decomposition rates but greater N release rate compared to natives. Accordingly, invasives are expected to affect N cycle in Mediterranean plant communities, possibly promoting a shift of plant assemblages

Climate Change and Reproductive Biocomplexity in Fishes: Innovative Management Approaches towards Sustainability of Fisheries and Aquaculture

The ongoing rapid climate change, combined with the disturbance of fish breeding grounds, may impact reproduction by endangering successful breeding and survival, and thus affect the viable sustainability in aquaculture systems as well as in the sea. In this study we focus on the biocomplexity of fish reproduction in response to climate change. Further, we propose adaptive strategies, including technological advancements, using a noninvasive and non-lethal approach, and we outline an assisted reproduction and nutrigenomics approach to mitigating fish reproductive risks posed by climate change. This was done in an effort to monitor fish aquaculture and ensure that, as a livelihood, it may provide a useful source of nutrition for our society

An electron spin resonance study of Mn<SUP>2+</SUP>doped calcium hydrazine carboxylate monohydrate

Single crystals of calcium hydrazine carboxylate, monohydrate have been studied by ESR of Mn2+ doped in the calcium sites. X-band ESR indicated a large crystal field splitting necessitating experiments at Q band. The analysis shows two magnetically inequivalent (but chemically equivalent) sites with g xx = 2.0042&#177;0.0038,g yy=2.0076 &#177;0.0029,g zz=2.0314&#177;0.001,A zz=0.0099&#177;0.0002 cm-1,A xx=0.0092&#177;0.0002 cm-1,A yy=0.0082&#177;0.0002 cm-1,D=3/2Dzz=0.0558&#177;0.0006 cm-1, and E=1/2 (Dyy-Dyy)=0.0127&#177;0.0002 cm-1. One of the principal components of the crystal field, (Dzz), is found to be along the Ca &#8596;Ca direction in the structure and a second one, (Dxx), along the perpendicular to the plane of the triangle formed by three neighbouring calciums. The A tensor is found to have an orientation different from that of the g and D tensors reflecting the low symmetry of the Ca2+ sites

Does a plant detect its neighbor if it is kin or stranger? Evidence from a common garden experiment

Unlike vagile organisms, plants perform a wide range of phenotypic responses to cope with environmental stresses. A special case of interaction with external factors is the ability of plants to recognize genetic relatedness of neighbour plants, actually well known as kin recognition. The present work aimed to provide a valuable contribution to the field of kin recognition in plants through a common garden experiment. To avoid bias involved in pot experiments, we perform an experiment in unconstrained root growth conditions comparing the development of coupled kin, non-kin and solitary plants of Xanthium italicum. Biometrics of plants with different genetic relatedness were measured, then architecture and competitive interaction were assessed using the relative interaction index (RII) for above and belowground portions of plants. X. italicum showed different allocation depending on the neighbourhood. Root biomass was declined in plants growing with kin compared to non-kin coupled plants, while plants coupled with kin allocated more shoot than roots compared to solitary plants. RII explains phenotypic response of decreased competition in roots rather than in shoots. Despite high values of RII for the aboveground portion, the architectural analysis of shoot, number, angle and length of branches and roots reveals dramatic but indistinctive change in the structure of plants growing near kin or non kin compared to a solitary plant. These results confirm phenotypic responses of kin recognition in unconstrained environment

Strategies to improve reference databases for soil microbiomes

Microbial populations in the soil are critical in our lives. The soil microbiome helps to grow our food, nourishing and protecting plants, while also providing important ecological services such as erosion protection, water filtration and climate regulation. We are increasingly aware of the tremendous microbial diversity that has a role in soil heath; yet, despite significant efforts to isolate microbes from the soil, we have accessed only a small fraction of its biodiversity. Even with novel cell isolation techniques

Circular RNAs Are the Predominant Transcript Isoform from Hundreds of Human Genes in Diverse Cell Types

Most human pre-mRNAs are spliced into linear molecules that retain the exon order defined by the genomic sequence. By deep sequencing of RNA from a variety of normal and malignant human cells, we found RNA transcripts from many human genes in which the exons were arranged in a non-canonical order. Statistical estimates and biochemical assays provided strong evidence that a substantial fraction of the spliced transcripts from hundreds of genes are circular RNAs. Our results suggest that a non-canonical mode of RNA splicing, resulting in a circular RNA isoform, is a general feature of the gene expression program in human cells

Monitoring Voltage-Dependent Charge Displacement of Shaker B-IR K+ Ion Channels Using Radio Frequency Interrogation

Here we introduce a new technique that probes voltage-dependent charge displacements of excitable membrane-bound proteins using extracellularly applied radio frequency (RF, 500 kHz) electric fields. Xenopus oocytes were used as a model cell for these experiments, and were injected with cRNA encoding Shaker B-IR (ShB-IR) K+ ion channels to express large densities of this protein in the oocyte membranes. Two-electrode voltage clamp (TEVC) was applied to command whole-cell membrane potential and to measure channel-dependent membrane currents. Simultaneously, RF electric fields were applied to perturb the membrane potential about the TEVC level and to measure voltage-dependent RF displacement currents. ShB-IR expressing oocytes showed significantly larger changes in RF displacement currents upon membrane depolarization than control oocytes. Voltage-dependent changes in RF displacement currents further increased in ShB-IR expressing oocytes after ∼120 µM Cu2+ addition to the external bath. Cu2+ is known to bind to the ShB-IR ion channel and inhibit Shaker K+ conductance, indicating that changes in the RF displacement current reported here were associated with RF vibration of the Cu2+-linked mobile domain of the ShB-IR protein. Results demonstrate the use of extracellular RF electrodes to interrogate voltage-dependent movement of charged mobile protein domains — capabilities that might enable detection of small changes in charge distribution associated with integral membrane protein conformation and/or drug–protein interactions

Gross hematuria caused by a congenital intrarenal arteriovenous malformation: a case report

<p>Abstract</p> <p>Introduction</p> <p>We report the case of a woman who presented with gross hematuria and was treated with a percutaneous embolization.</p> <p>Case presentation</p> <p>A 48-year-old Caucasian woman presented with gross hematuria, left flank pain, and clot retention. The patient had no history of renal trauma, hypertension, urolithiasis, or recent medical intervention with percutaneous instrumentation. The patient did not report any bleeding disorder and was not taking any medication. Her systolic and diastolic blood pressure values were normal at presentation. The patient had anemia (8 mg/dL) and tachycardia (110 bpm). She underwent color and spectral Doppler sonography, multi-slice computed tomography, and angiography of the kidneys, which showed a renal arteriovenous malformation pole on top of the left kidney.</p> <p>Conclusions</p> <p>The feeding artery of the arteriovenous malformation was selectively embolized with a microcatheter introduced using a right transfemoral approach. By using this technique, we stopped the bleeding, preserved renal parenchymal function, and relieved the patient's symptoms. The hemodynamic effects associated with the abnormality were also corrected.</p

Normalizing single-cell RNA sequencing data: challenges and opportunities

Single-cell transcriptomics is becoming an important component of the molecular biologist's toolkit. A critical step when analyzing data generated using this technology is normalization. However, normalization is typically performed using methods developed for bulk RNA sequencing or even microarray data, and the suitability of these methods for single-cell transcriptomics has not been assessed. We here discuss commonly used normalization approaches and illustrate how these can produce misleading results. Finally, we present alternative approaches and provide recommendations for single-cell RNA sequencing users