The biogeochemical influence of nitrate, dissolved oxygen, and dissolved organic carbon on stream nitrate uptake

Streams are potential hotspots for retention and removal of NO3−, and understanding the mechanisms that enhance NO3− reactivity in stream systems is critical for predicting and preventing eutrophication. Both dissolved organic C (DOC) and dissolved O2 (DO) influence NO3− removal processes. Assessing the individual impacts of NO3−, DO, and DOC concentrations on stream NO3− removal is difficult because these factors covary and are coupled through the C and N cycles. We used an experimental approach to quantify the influences of NO3−, DOC, and DO on NO3− transport in headwater streams of the Ipswich and Parker River watersheds (Massachusetts, USA) with contrasting levels of DOC and DO. In a 1st set of experiments, we added NO3− to address how uptake kinetics differed between a low-DO/high-DOC stream (Cedar Swamp Creek) and a high-DO/low-DOC stream (Cart Creek). In a 2nd set of experiments, we manipulated, for the first time at the reach scale, both DO and DOC in a factorial experiment. DO was added to the low-DO stream by injecting O2 and was removed from the high-DO stream by adding sodium sulfite. DOC was added both alone and in combination with the DO manipulations. NO3− concentration was an important control of NO3− uptake velocity in our study streams, consistent with previous findings. The results of the DOC and DO manipulations suggested that DO determines whether a stream has net NO3− uptake or production and that the presence of DOC magnifies the DO response processes. Addition of DOC by itself did not lead to increased NO3− uptake. In addition, we observed organic matter priming effects, wherein the addition of labile organic matter resulted in accelerated metabolism of naturally occurring DOC in the water column. Priming effects have not been reported previously in stream systems. Results from our experiments suggest that NO3− uptake in streams might arise from complex interactions among DOC, DO, and NO3−, and ultimately, from the influence of DO on dominant stream processes

IT Outsourcing in Finnish Business

This paper reviews the characteristics and magnitude of information technology (IT) outsourcing as well as studies its labor productivity effects with a representative sample of Finnish businesses. Depending on the IT task in question, on average from one-third to two-thirds of IT has been outsourced; of the ten categories considered, the development of non-Internet business-to-business applications (e.g., EDI) is the leading activity in this respect. The various dimensions of IT outsourcing are all highly positively correlated. After controlling for industry and regional effects as well as characteristics of firms and their employees, it is found that an externally-supported computer user is about 20% more productive than an otherwise similar worker without a computer, which corresponds to about 5% output elasticity of outsourced IT; the effect of internally-supported computer use is not statistically significantly different for zero, and it is also several times smaller in magnitude. While the issues of causality, timing, self-selection, and unobserved firm heterogeneity are not fully addressed, the findings nevertheless suggest that IT outsourcing may have significant economic consequences

Bandwidth Estimation for Admission Control in MANET: Review and Conceptual MANET Admission Control Framework

The widespread of wireless mobile network have increased the demand for its applications. Providing a reliable QoS in wireless medium, especially mobile ad-hoc network (MANET), is quite challenging and remains an ongoing research trend. One of the key issues of MANET is its inability to accurately predict the needed and available resources to avoid interference with already transmitting traffic flow. In this work, we propose a resource allocation and admission control (RAAC) solution. RAAC is an admission control scheme that estimates the available bandwidth needed within a network, using a robust and accurate resource estimation technique. Simulation results obtained show that our proposed scheme for MANET can efficiently estimate the available bandwidth and outperforms other existing approaches for admission control with bandwidth estimation

Concentrations of potentially toxic elements and soil environmental quality evaluation of a typical Prosecco vineyard of the Veneto region (NE Italy)

Purpose The aim of this work was to assess the concentrations of potentially toxic elements and to evaluate the soil quality of a typical Prosecco Denomination of Controlled and Guaranteed Origin vineyard of the Veneto region, NE Italy. Materials and methods Soil samples and leaves of Taraxacum officinale and Vitis vinifera were collected during spring–summer 2014. Element determination (Al, Cd, Cr, Cu, Fe, Mg, Mn, Ni, P, Pb, V, and Zn) were performed with ICP-OES after microwave digestion of samples. Soil quality was assessed via the biological soil quality (BSQ-ar) index. Lipid peroxidation test was performed to evaluate the vegetation oxidative stress, based on malondialdehyde (MDA) content via spectrophotometer. Results and discussion High concentrations of Al,Mg, and P were identified in soil, while high contents of Al, Cu, Fe, and Zn were found in V. vinifera leaves. The high concentrations in soil are probably due to agricultural activities, whereas those in leaves are probably due to atmospheric deposition and repeated use of foliar sprays in viticulture. The bioconcentration factor showed an effective transport of Cu, P, and Zn, from soil to leaf. The BSQ-ar values registered were similar to those obtained in preserved soils; hence, the biological class (VI) of these soils is high. The MDA content in T. officinale and V. vinifera leaves was below the reference value for T. officinale (2.9 ± 0.2 μM), suggesting that the metal content did not stress the vegetation in the investigated site. Conclusions The MDA value for V. vinifera (1.1 ± 0.7 μM) could be adopted as another control value for soil quality, which in our case is of Bgood quality.^ Moreover, our results suggest that high concentrations of elements detected in the analyzed samples do not influence negatively the quality of soil, but a better agronomic management could improve soil quality in the studied area

Early onset absence epilepsy: 1 in 10 cases is caused by GLUT1 deficiency

Fulltext embargoed for: 12 months post date of publicationGlucose transporter 1 (GLUT1) deficiency caused by mutations of SLC2A1 is an increasingly recognized cause of genetic generalized epilepsy. We previously reported that >10% (4 of 34) of a cohort with early onset absence epilepsy (EOAE) had GLUT1 deficiency. This study uses a new cohort of 55 patients with EOAE to confirm that finding. Patients with typical absence seizures beginning before 4 years of age were screened for solute carrier family 2 (facilitated glucose transporter), member 1 (SLC2A1) mutations or deletions. All had generalized spike-waves on electroencephalography (EEG). Those with tonic and/or atonic seizures were excluded. Mutations were found in 7 (13%) of 55 cases, including five missense mutations, an in-frame deletion leading to loss of a single amino acid, and a deletion spanning two exons. Over both studies, 11 (12%) of 89 probands with EOAE have GLUT1 deficiency. Given the major treatment and genetic counseling implications, this study confirms that SLC2A1 mutational analysis should be strongly considered in EOAE

Analysis of multi-sensor, multi-spectral, active and passive imaging measurements.

We study the complementarity of active and passive EO sensors in different spectral bands, applied to friend or foe identification of human activities and of individuals. Laser imaging may complement radar or passive EO sensors. The laser may be fired only when required. During field trials, we have recorded dynamic scenarios of interest with as many as ten sensors simultaneously: three active sensors in the NIR and SWIR regions, and seven passive sensors from the blue to the LWIR. The scenes include personnel using objects of interest, as well as reflectance and resolution targets. A good dataset was recorded, for distances from 600 to 1000 m, against different backgrounds and under a variety of atmospheric conditions. These experimental data are under analysis to determine and understand the key phenomena that can be exploited for enhancing target-tobackground discrimination and for defining sensor combinations of interest. We present first results

Rhizobium-legume symbiosis in the absence of Nod factors : two possible scenarios with or without the T3SS

The occurrence of alternative Nod factor (NF)-independent symbiosis between legumes and rhizobia was first demonstrated in some Aeschynomene species that are nodulated by photosynthetic bradyrhizobia lacking the canonical nodABC genes. In this study, we revealed that a large diversity of non-photosynthetic bradyrhizobia, including B. elkanii, was also able to induce nodules on the NFindependent Aeschynomene species, A. indica. Using cytological analysis of the nodules and the nitrogenase enzyme activity as markers, a gradient in the symbiotic interaction between bradyrhizobial strains and A. indica could be distinguished. This ranged from strains that induced nodules that were only infected intercellularly to rhizobial strains that formed nodules in which the host cells were invaded intracellularly and that displayed a weak nitrogenase activity. In all nonphotosynthetic bradyrhizobia, the type III secretion system (T3SS) appears required to trigger nodule organogenesis. In contrast, genome sequence analysis revealed that apart from a few exceptions, like the Bradyrhizobium ORS285 strain, photosynthetic bradyrhizobia strains lack a T3SS. Furthermore, analysis of the symbiotic properties of an ORS285 T3SS mutant revealed that the T3SS could have a positive or negative role for the interaction with NF-dependent Aeschynomene species, but that it is dispensable for the interaction with all NF-independent Aeschynomene species tested. Taken together, these data indicate that two NF-independent symbiotic processes are possible between legumes and rhizobia: one dependent on a T3SS and one using a so far unknown mechanism