4,223 research outputs found

    Influence of microalgal N and P composition on wastewater nutrient remediation

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    Microalgae have demonstrated the ability to remediate wastewater nutrients efficiently, with methods to further enhance performance through species selection and biomass concentration. This work evaluates a freshwater species remediation characteristics through analysis of internal biomass N:P (nitrogen:phosphorus) and presents a relationship between composition and nutrient uptake ability to assist in species selection. Findings are then translated to an optimal biomass concentration, achieved through immobilisation enabling biomass intensification by modifying bead concentration, for wastewaters of differing nutrient concentrations at hydraulic retention times (HRT) from 3 h to 10 d. A HRT <20 h was found suitable for the remediation of secondary effluent by immobilised Scenedesmus obliquus and Chlorella vulgaris at bead concentrations as low as 3.2 and 4.4 bead·mL−1. Increasing bead concentrations were required for shorter HRTs with 3 h possible at influent concentrations <5 mgP L−1

    Fractal geometry in an expanding, one-dimensional, Newtonian universe

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    International audienceObservations of galaxies over large distances reveal the possibility of a fractal distribution of their positions. The source of fractal behavior is the lack of a length scale in the two body gravitational interaction. However, even with new, larger, sample sizes from recent surveys, it is difficult to extract information concerning fractal properties with confidence. Similarly, three-dimensional N-body simulations with a billion particles only provide a thousand particles per dimension, far too small for accurate conclusions. With one-dimensional models these limitations can be overcome by carrying out simulations with on the order of a quarter of a million particles without compromising the computation of the gravitational force. Here the multifractal properties of two of these models that incorporate different features of the dynamical equations governing the evolution of a matter dominated universe are compared. For each model at least two scaling regions are identified. By employing criteria from dynamical systems theory it is shown that only one of them can be geometrically significant. The results share important similarities with galaxy observations, such as hierarchical clustering and apparent bifractal geometry. They also provide insights concerning possible constraints on length and time scales for fractal structure. They clearly demonstrate that fractal geometry evolves in the µ (position, velocity) space. The observed patterns are simply a shadow (projection) of higher-dimensional structure

    Lunar drill footplate and casing

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    To prevent hole collapse during lunar drilling operations, a casing has been devised of a graphite reinforced polyimide composite which will be able to withstand the lunar environment. Additionally, this casing will be inserted into the ground in segments two meters long which will penetrate the regolith simultaneously with the auger. The vertical action of the mobile platform will provide a downward force to the casing string through a special adaptor, giving the casing the needed impetus to sink the anticipated depth of ten meters. Casing segments will be connected with a simple snap arrangement. Excess casing will be cut off by a cylindrical cutting tool which will also transport the excess casing away from the hole. A footplate will be incorporated to grasp the auger rod string during rod segment additions or removals. The footplate grasping mechanism will consist of a set of vice-like arms, one end of each bearing threaded to a common power screw. The power screw will be threaded such that one end's thread pitch opposes that of the other end. The weight of the auger and rod string will be transmitted through the arms to the power screw and absorbed by a set of three ball bearing assemblies. The power screw will be driven by a one-half horsepower brushless motor actuated by radio control. The footplate will rest on four short legs and be anchored with pins that are an integral part of each leg

    Development of Fractal Geometry in a 1+1 Dimensional Universe

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    Observations of galaxies over large distances reveal the possibility of a fractal distribution of their positions. The source of fractal behavior is the lack of a length scale in the two body gravitational interaction. However, even with new, larger, sample sizes from recent surveys, it is difficult to extract information concerning fractal properties with confidence. Similarly, simulations with a billion particles only provide a thousand particles per dimension, far too small for accurate conclusions. With one dimensional models these limitations can be overcome by carrying out simulations with on the order of a quarter of a million particles without compromising the computation of the gravitational force. Here the multifractal properties of a group of these models that incorporate different features of the dynamical equations governing the evolution of a matter dominated universe are compared. The results share important similarities with galaxy observations, such as hierarchical clustering and apparent bifractal geometry. They also provide insights concerning possible constraints on length and time scales for fractal structure. They clearly demonstrate that fractal geometry evolves in the μ\mu (position, velocity) space. The observed properties are simply a shadow (projection) of higher dimensional structure

    Aires protégées : espaces durables ?

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    Comparison of insulin detemir and insulin glargine in a Basal-Bolus regimen, with insulin aspart as the mealtime insulin, in patients with type 1 diabetes: A 52-week, multinational, randomized, open-label, parallel-group, treat-to-target noninferiority trial

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    Objective: The primary study objective was to determine whether insulin detemir (detemir) was noninferior to insulin glargine (glargine) as the basal insulin in a basal-bolus regimen, with insulin aspart as the mealtime insulin, in terms of glycemic control at the end of 52 weeks in patients with type I diabetes mellitus (T1DM). Methods: This multinational, open-label, parallel-group, treat-to-target, noninferiority trial enrolled patients aged >= 18 years who had had T1DM for at least 12 months, had been taking a basal-bolus insulin regimen for at least 3 months, and had a glycosylated hemoglobin (HbA(1c)) value <= 11.0% at screening. Patients were randomized in a 2:1 ratio to receive either detemir or glargine for 52 weeks. The basal insulin was initially administered once daily (in the evening) in both groups; if patients in the detemir group were achieving the plasma glucose (PG) target before breakfast but not before dinner, they were switched to twice-daily administration. Glargine was administered once daily throughout the trial, according to its approved labeling. Each patient attended 13 study visits and received 16 scheduled telephone calls from the trial site. The primary efficacy end point was glycemic control (HbA(1c)) after 52 weeks of treatment. Secondary end points included the number of patients achieving an HbAlc value <= 7.0%, with or without a major hypoglycemic episode in the last month of treatment; fasting PG (FPG); within-patient variation in self-monitored plasma glucose (SMPG) before breakfast and dinner; and 10-point SMPG profiles. The noninferiority margin was 0.4%, consistent with US Food and Drug Administration guidelines. Results: Four hundred forty-three patients (mean [SD] age, 42 [12] years; body mass index, 26.5 [4.0] kg/m(2); duration of diabetes, 17.2 [11.4] years; HbA(1c), 8.1% [1.1%]) received study treatment. After 52 weeks, the estimated mean HbA(1c) did not differ significantly between the detemir and glargine groups (7.57% and 7.56%, respectively; mean difference, 0.01%; 95% CI -0.13 to 0.16), consistent with the noninferiority of detemir to glargine. The corresponding estimated changes in HbA(1c) were -0.53% and -0.54%. In the 90 patients who completed the trial on once-dally detemir and the 173 patients who completed the trial on twice-daily detemir, the estimated changes in HbA(1c) were-0.49% and -0.58%, respectively. After 52 weeks, there were no significant differences in the proportions of those receiving detemir and glargine who achieved an HbA(1c) value <= 7.0% without major hypo-glycemia (31.9% and 28.9%, respectively). In addition, there were no significant differences in estimated mean FPG (8.58 and 8.81 rnmol/L; mean difference, -0.23 mmol/L; 95% CI, -1.04 to 0.58) or in basal insulin doses. The basal insulin dose was numerically higher in patients receiving detemir twice rather than once daily (0.47 vs 0.33 U/kg, respectively). The relative risks for total and nocturnal hypoglycemia with detemir versus glargine were 0.94 and 1.12, respectively (both, P = NS). Six patients (2.0%) randomized to the detemir group and 4 (2.7%) randomized to the glargine group withdrew due to adverse events. Conclusions: During 52 weeks of basal-bolus therapy in patients with T1DM, detemir was noninferior to glargine in terms of overall glycemic control (HbA(1c)). When used according to the approved labeling, detemir and glargine did not differ in tolerability or in terms of the occurrence of hypoglycemia. (Clin Ther. 2009; 31:2086-2097) (C) 2009 Excerpta Medica Inc

    Soluble Epoxide Hydrolase in Atherosclerosis

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    Like many eicosanoids, epoxyeicosatrienoic acids (EETs) have multiple biological functions, including reduction of blood pressure, inflammation, and atherosclerosis in multiple species. Hydration of EETs by the soluble epoxide hydrolase (sEH) is the major route of their degradation to the less bioactive diols. Inhibition of the sEH stabilizes EETs, thus, enhancing the beneficial effects of EETs. Human data show an association of sEH (Ephx2) gene polymorphisms with increased risk of atherosclerosis and cardiovascular diseases. These data suggest a potential therapeutic effect of sEH inhibitors (sEHI) in the treatment of atherosclerosis. Indeed, two laboratories reported independently that using different sEHIs in apolipoprotein E–deficient mice significantly attenuated atherosclerosis development and aneurysm formation. The antiatherosclerotic effects of sEHI are correlated with elevation in EET levels and associated with reduction of low-density lipoprotein and elevation of high-density lipoprotein cholesterols, as well as attenuation of expression of proinflammatory genes and proteins. In addition, the antihypertensive effects and improvement of endothelial function also contribute to the mechanism of the antiatherosclerotic effects of sEHI. The broad spectrum of biological action of EETs and sEHIs with multiple biological beneficial actions provides a promising new class of therapeutics for atherosclerosis and other cardiovascular diseases

    Characterisation of a non-pathogenic and non-protective infectious rabbit lagovirus related to RHDV

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    The existence of non-pathogenic RHDV strains was established when a non-lethal virus named rabbit calicivirus (RCV) was characterised in 1996 in Italy. Since then, different RNA sequences related to RHDV have been detected in apparently healthy domestic and wild rabbits, and recently a new lagovirus was identified in Australia. We have characterised from seropositive healthy domestic rabbits a non-lethal lagovirus that differs from RHDV in terms of pathogenicity, tissue tropism and capsid protein sequence. Phylogenetic analyses have revealed that it is close to the Ashington strain and to the RCV, but distinct. We proved experimentally that it is infectious but non-pathogenic and demonstrated that, contrary to the other described non-pathogenic lagoviruses, it induces antibodies that do not protect against RHDV. Our results indicate the existence of a gradient of cross-protection between circulating strains, from non-protective, partially protective to protective strains, and highlight the extent of diversity within the genus Lagovirus
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