► The present work provides field evidence on the effect of biochar on GHG fluxes in Mediterranean wheat crop. ► No significant increase of N
2O and CO
2 emissions observed in char treated plots. ► ...No significant effect of char on CH
4 soil consumption and production. ► Short term stimulating effect of biochar on soil microflora.
Biochar has been recently proposed as a management strategy to improve crop productivity and global warming mitigation. However, the effect of such approach on soil greenhouse gas fluxes is highly uncertain and few data from field experiments are available. In a field trial, cultivated with wheat, biochar was added to the soil (3 or 6
kg
m
−2) in two growing seasons (2008/2009 and 2009/2010) so to monitor the effect of treatments on microbial parameters 3
months and 14
months after char addition. N
2O, CH
4 and CO
2 fluxes were measured in the field during the first year after char addition. Biochar incorporation into the soil increased soil pH (from 5.2 to 6.7) and the rates of net N mineralization, soil microbial respiration and denitrification activity in the first 3
months, but after 14
months treated and control plots did not differ significantly. No changes in total microbial biomass and net nitrification rate were observed. In char treated plots, soil N
2O fluxes were from 26% to 79% lower than N
2O fluxes in control plots, excluding four sampling dates after the last fertilization with urea, when N
2O emissions were higher in char treated plots. However, due to the high spatial variability, the observed differences were rarely significant. No significant differences of CH
4 fluxes and field soil respiration were observed among different treatments, with just few exceptions. Overall the char treatments showed a minimal impact on microbial parameters and GHG fluxes over the first 14
months after biochar incorporation.
Abstract
Objective
The dorsal root ganglion (DRG) is a novel target for neuromodulation, and DRG stimulation is proving to be a viable option in the treatment of chronic intractable neuropathic pain. ...Although the overall principle of conventional spinal cord stimulation (SCS) and DRG stimulation—in which an electric field is applied to a neural target with the intent of affecting neural pathways to decrease pain perception—is similar, there are significant differences in the anatomy and physiology of the DRG that make it an ideal target for neuromodulation and may account for the superior outcomes observed in the treatment of certain chronic neuropathic pain states. This review highlights the anatomy of the DRG, its function in maintaining homeostasis and its role in neuropathic pain, and the unique value of DRG as a target in neuromodulation for pain.
Methods
A narrative literature review was performed.
Results
Overall, the DRG is a critical structure in sensory transduction and modulation, including pain transmission and the maintenance of persistent neuropathic pain states. Unique characteristics including selective somatic organization, specialized membrane characteristics, and accessible and consistent location make the DRG an ideal target for neuromodulation. Because DRG stimulation directly recruits the somata of primary sensory neurons and harnesses the filtering capacity of the pseudounipolar neural architecture, it is differentiated from SCS, peripheral nerve stimulation, and other neuromodulation options.
Conclusions
There are several advantages to targeting the DRG, including lower energy usage, more focused and posture-independent stimulation, reduced paresthesia, and improved clinical outcomes.
We report the results of detailed calculations of reactive, inelastic, and dissociative processes in collisions of atomic oxygen with molecular nitrogen in their respective electronic ground states. ...Cross sections are calculated as a function of collision energy in the range 0.001–10 eV, considering the whole rovibrational ladder. Some problems related to the vibrational energy levels of the asymptotes of 3A″ and 3A′ potential energy surfaces used in this work are solved by an appropriate scaling at the level of cross sections. The results are compared with data in the literature, obtaining excellent agreement with experimental thermal data for reactive processes on a very large temperature range, and reasonable agreement with indirect dissociative data. Significant discrepancies are observed with previous reactive state-to-state results calculated on less detailed potential energy surfaces. Inelastic results are compatible with extrapolation of experimental thermal rate coefficient for temperatures higher than 4500 K but completely fail to reproduce experimental data at room temperature. The issue is discussed, indicating the reasons and possible solutions to the problem, and a resonable rate coefficient is obtained combining experimental and theoretical results in the range 300–20000 K. Complete, accurate fits are provided for both reactive and dissociative state-to-state rate coefficients to use them in applicative numerical codes concerning air kinetics.
Display omitted
•N + O2 collisions: reactive, inelastic, dissociation vibrationally-detailed rates fit.•State-to-state vibrational kinetics model of a N2/N/O2/O/NO mixture.•0-dimensional ...time-dependent model as preliminary step in plasma medicine modelling.•Hypersonic boundary layer model to simulate fast transportation problems.
The reactive, inelastic and dissociation vibrationally-detailed rate coefficients of the N + O2 collision processes, previously calculated by means of a QCT method, have been interpolated as a function of the initial and final vibrational levels and of the temperature, in the range 1000–20000 K. These rates have been implemented in a N2/N/O2/O/NO mixture state-to-state kinetic model. The model has been tested in a couple of applications. The first consists in its time evolution, for 10−3 s, from an equilibrium composition at 4000/3000 K towards a new composition obtained by suddenly decreasing the temperature to 1000 K. This is a preliminary study that could open the way to a new approach in the investigation of some biomedical applications governed by plasma sources at atmospheric pressure.
The second test regards the boundary layer formed around the nose of a hypersonic vehicle in the framework of the fast transportation and space tourism applications.
Mineral dust particles represent the most abundant component of atmospheric aerosol in terms of dry mass. They play a key role in climate and climate change, so the study of their emission processes ...is of utmost importance. Measurements of dust emission into the atmosphere are scarce, so that the dust load is generally estimated using models. It is known that the emission process can generate strong atmospheric electric fields. Starting from the data we acquired in the Sahara desert, here, we show for the first time that depending on the relative humidity conditions, electric fields contribute to increase up to a factor of 10 the amount of particles emitted into the atmosphere. This means that electrical forces and humidity are critical quantities in the dust emission process and should be taken into account in climate and circulation models to obtain more realistic estimations of the dust load in the atmosphere.
Key Points
The tight interrelation between the dust‐lifting process and atmospheric electric field is shown
The role of the relative humidity is demonstrated
Electric forces contribute to the entrainment of dust in the atmosphere
We consider positive singular solutions to semilinear elliptic problems with possibly singular nonlinearity. We deduce symmetry and monotonicity properties of the solutions via the moving plane ...procedure.
Key points
Vascular function and arterial stiffness are important markers of cardiovascular health and cardiovascular co‐morbidity.
Transitional phases of hypoemia and hypermia, with consequent ...fluctuations in shear rate, occuring during repetitive passive stretching adminstration (passive stretching training) may constitute an effective stimulus to induce an amelioration in vascular function, arterial stiffness and vascular remodelling by improving central and local blood flow control mechanisms.
Vascular function, arterial stiffness and vascular remodelling were evaluated before and after 12 weeks of passive stretching training and after 6 weeks from training cessation, in the femoral, popliteal (treated with stretching), and brachial arteries (untreated) of both sides.
After passive stretching training, vascular function and arterial remodelling improved, and arterial stiffness decreased in all the arteries, suggesting modifications of both central and local blood flow control mechanisms. Passive stretching‐induced improvements related to central mechanisms seemed to have a short duration, as they returned to pre‐training baseline within 6 weeks from training cessation, whereas those more related to a local mechanism persisted in the follow‐up.
Acute passive stretching (PS) effects on blood flow (Q̇), shear rate (Ẏ), and vascular function in the feeding arteries of the stretched muscle have been extensively investigated; however, few data are available on vascular adjustments induced by long‐term PS training. We investigated the effects of PS training on vascular function and stiffness of the involved (femoral and popliteal) and uninvolved (brachial) arteries. Our hypothesis was that PS‐induced changes in Q̇ and Ẏ would improve central and local mechanisms of Q̇ control. Thirty‐nine participants were randomly assigned to bilateral PS (n = 14), monolateral PS (n = 13) or no PS training (n = 12). Vascular function was measured before and after 12 weeks of knee extensor and plantar flexor muscles’ PS training by single passive limb movement and flow‐mediated dilatation (FMD). Central (carotid‐femoral artery PWV, PWVCF) and peripheral (carotid‐radial artery PWV, PWVCR) arterial stiffness was measured by pulse‐wave velocity (PWV), together with systolic (SBP) and diastolic (DBP) blood pressure. After PS training, increases of 30%, 25% and 8% (P < 0.05) in femoral ΔQ̇, popliteal and brachial artery FMD%, respectively, occurred in both PS training groups. A decrease in PWVCF, PWVCR, SBP and DBP (−25%, −17%, −4% and −8%, respectively; P < 0.05) was noted. No changes occurred in controls. Vascular function improved and arterial stiffness reduced in the arteries involved and uninvolved with PS training, suggesting modifications in both central and local Q̇ control mechanisms. PS‐induced improvements had a short duration in some of vascular function parameters, as they returned to baseline within 6 weeks of PS training cessation.
Key points
Vascular function and arterial stiffness are important markers of cardiovascular health and cardiovascular co‐morbidity.
Transitional phases of hypoemia and hypermia, with consequent fluctuations in shear rate, occuring during repetitive passive stretching adminstration (passive stretching training) may constitute an effective stimulus to induce an amelioration in vascular function, arterial stiffness and vascular remodelling by improving central and local blood flow control mechanisms.
Vascular function, arterial stiffness and vascular remodelling were evaluated before and after 12 weeks of passive stretching training and after 6 weeks from training cessation, in the femoral, popliteal (treated with stretching), and brachial arteries (untreated) of both sides.
After passive stretching training, vascular function and arterial remodelling improved, and arterial stiffness decreased in all the arteries, suggesting modifications of both central and local blood flow control mechanisms. Passive stretching‐induced improvements related to central mechanisms seemed to have a short duration, as they returned to pre‐training baseline within 6 weeks from training cessation, whereas those more related to a local mechanism persisted in the follow‐up.
ABSTRACT The Rosetta probe, orbiting Jupiter-family comet 67P/Churyumov-Gerasimenko, has been detecting individual dust particles of mass larger than 10−10 kg by means of the GIADA dust collector and ...the OSIRIS Wide Angle Camera and Narrow Angle Camera since 2014 August and will continue until 2016 September. Detections of single dust particles allow us to estimate the anisotropic dust flux from 67P, infer the dust loss rate and size distribution at the surface of the sunlit nucleus, and see whether the dust size distribution of 67P evolves in time. The velocity of the Rosetta orbiter, relative to 67P, is much lower than the dust velocity measured by GIADA, thus dust counts when GIADA is nadir-pointing will directly provide the dust flux. In OSIRIS observations, the dust flux is derived from the measurement of the dust space density close to the spacecraft. Under the assumption of radial expansion of the dust, observations in the nadir direction provide the distance of the particles by measuring their trail length, with a parallax baseline determined by the motion of the spacecraft. The dust size distribution at sizes >1 mm observed by OSIRIS is consistent with a differential power index of −4, which was derived from models of 67P's trail. At sizes <1 mm, the size distribution observed by GIADA shows a strong time evolution, with a differential power index drifting from −2 beyond 2 au to −3.7 at perihelion, in agreement with the evolution derived from coma and tail models based on ground-based data. The refractory-to-water mass ratio of the nucleus is close to six during the entire inbound orbit and at perihelion.
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