7,665 research outputs found
Ion Exchange-Precipitation for Nutrient Recovery from Dilute Wastewater
Regulated phosphorus (P) and nitrogen (N) discharges and the cost of fertilizer provide economic drivers for nutrient removal and recovery from wastewater. This study used ion exchange (IX) in dilute (domestic) wastewater to concentrate nutrients with subsequent recovery by struvite precipitation. This is the first tertiary wastewater treatment study directly comparing P removal using a range of Fe, Cu, and Al-based media followed by clinoptilolite IX columns for N removal and precipitation using the combined regenerants. Phosphate removal prior to breakthrough was 0.5–2.0 g P Lmedia−1, providing effluent concentrations −1 PO4-P and −1 NH4-N for ≥80 bed volumes. Dow-FeCu resin provided effective P removal, efficient neutral pH regeneration and 560 mg P L−1 in the regeneration eluate (≥100× concentration factor). Exchange capacity of clinoptilolite in column mode was 3.9–6.1 g N Lmedia−1 prior to breakthrough. Precipitation using the combined cation and anion regenerants resulted in a maximum of 74% P removal using Dow-FeCu. Precipitates contained impurities, including Al3+, Ca2+, and Fe. Overall, the IX-precipitation recovery process removed ≥98% P and 95% N and precipitates contained 13% P and 1.6% N. This sequential process can satisfy increasingly stringent wastewater standards and offers an effective alternative to traditional treatment technologies that simply remove nutrients. Approximately 84% of total P and 97% of total Kjeldahl N entering a treatment plant can be captured (accounting for primary clarifier removal), whereas most existing technologies target side streams that typically contain only 20–30% of influent P and 15–20% of influent N
A discrete time-dependent method for metastable atoms in intense fields
The full-dimensional time-dependent Schrodinger equation for the electronic
dynamics of single-electron systems in intense external fields is solved
directly using a discrete method.
Our approach combines the finite-difference and Lagrange mesh methods. The
method is applied to calculate the quasienergies and ionization probabilities
of atomic and molecular systems in intense static and dynamic electric fields.
The gauge invariance and accuracy of the method is established. Applications to
multiphoton ionization of positronium and hydrogen atoms and molecules are
presented. At very high intensity above saturation threshold, we extend the
method using a scaling technique to estimate the quasienergies of metastable
states of the hydrogen molecular ion. The results are in good agreement with
recent experiments.Comment: 10 pages, 9 figure, 4 table
Seedling Survival and Natural Regeneration For a Bottomland Hardwood Planting on Sites Differing in Site Preparation
In January 1998, three tracts in Hardin County, TX, were hand-planted with seven species of 1-0 bareroot bottomland hardwood seedlings. The tracts, managed by The Nature Conservancy of Texas, were previously 20-year-old pine plantations. The tracts are located within the floodplain of Village Creek. An objective for this conversion is the restoration of a bottomland hardwood wetland in order to meet Clean Water Act requirements. A pre-harvest plant inventory was conducted for each tract. The tracts were clearcut during the Winter and Spring of 1997. Following harvest, each tract was subjected to a different site preparation technique. One tract was burned. Another tract was treated with herbicide to control Chinese tallow. The third tract was sheared, piled, burned and ripped. Planted seedling survival was greatest (72 percent) on the tract that was sheared, piled, burned and ripped. Hardwood natural regeneration was proportionally higher on the tract prepared by burning only. However, this tract appeared to have a greater potential for hardwood root collar sprouting following harvest of the pine overstory. Chinese tallow was a large portion of all natural woody regeneratton on each tract
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Numerical Model for the Determination of Erythrocyte Mechanical Properties and Wall Shear Stress in vivo From Intravital Microscopy.
The mechanical properties and deformability of Red Blood Cells (RBCs) are important determinants of blood rheology and microvascular hemodynamics. The objective of this study is to quantify the mechanical properties and wall shear stress experienced by the RBC membrane during capillary plug flow in vivo utilizing high speed video recording from intravital microscopy, biomechanical modeling, and computational methods. Capillaries were imaged in the rat cremaster muscle pre- and post-RBC transfusion of stored RBCs for 2-weeks. RBC membrane contours were extracted utilizing image processing and parametrized. RBC parameterizations were used to determine updated deformation gradient and Lagrangian Green strain tensors for each point along the parametrization and for each frame during plug flow. The updated Lagrangian Green strain and Displacement Gradient tensors were numerically fit to the Navier-Lame equations along the parameterized boundary to determined Lame's constants. Mechanical properties and wall shear stress were determined before and transfusion, were grouped in three populations of erythrocytes: native cells (NC) or circulating cells before transfusion, and two distinct population of cells after transfusion with stored cells (SC1 and SC2). The distinction, between the heterogeneous populations of cells present after the transfusion, SC1 and SC2, was obtained through principle component analysis (PCA) of the mechanical properties along the membrane. Cells with the first two principle components within 3 standard deviations of the mean, were labeled as SC1, and those with the first two principle components greater than 3 standard deviations from the mean were labeled as SC2. The calculated shear modulus average was 1.1±0.2, 0.90±0.15, and 12 ± 8 MPa for NC, SC1, and SC2, respectively. The calculated young's modulus average was 3.3±0.6, 2.6±0.4, and 32±20 MPa for NC, SC1, and SC2, respectively. o our knowledge, the methods presented here are the first estimation of the erythrocyte mechanical properties and shear stress in vivo during capillary plug flow. In summary, the methods introduced in this study may provide a new avenue of investigation of erythrocyte mechanics in the context of hematologic conditions that adversely affect erythrocyte mechanical properties
Education for Innovation (E4I): Exploring the Developmental Process of a Canadian Curriculum Resource
The Rideau Hall Foundation (RHF) in Ottawa, Canada selected the Schulich School of Education (SSoE) at Nipissing University to create educational resources to correspond with the release of two 2017 publications (Innovation Nation written for emergent readers; and Ingenious written for older readers. Both books were co-authored by The Right Honourable David Johnston (former Governor General of Canada) and Tom Jenkins as part of the Canada 150 sesquicentennial celebrations. The SSoE organized school teacher writing teams in summer 2017 and produced three cross-curricular Education for Innovation (E4I) resources (Early Learning; Grades 1-8; Grades 7-12) each of which included an Innovation Cycle model, sample key innovation learning experiences, and suggestions for culminating Innovation Celebrations. Teacher candidates from participating SSoE faculty classes also created curriculum-specific Innovation units which were subsequently revised by teacher teams and then implemented and reviewed by teachers from different educational contexts (e.g., public schools, private schools, homeschools). The E4I project collaboration involved university faculty, teachers, teacher candidates, and community partners. Based on participant survey data, researchers identified reported benefits and challenges relating to the overall developmental process. Findings indicate that the experiences of inquiring, ideating, incubating, and implementing the E4I resources closely reflected the phases found within the Innovation Cycle model. Feedback from teachers confirmed the usefulness of E4I for promoting innovation skills and mindsets in their students. Further themes emerging from the process survey data analysis include the evidence of, and need for: solid leadership, flexible support, iterative mindsets, and organic organizational structures.
Key words: Innovation, Education, Curriculum, Interdisciplinary
La Fondation Rideau Hall (FRH) à Ottawa, Canada, a sélectionné la Schulich School of Education (SSoE) de l’Université Nipissing pour élaborer des ressources didactiques dans le cadre de la publication de deux livres en 2017, Innovation Nation pour lecteurs débutants et Ingenious pour lecteurs plus âgés. Les deux livres ont été rédigés par le très honorable David Johnston, ancien Gouverneur général du Canada, en collaboration avec Tom Jenkins dans le cadre des célébrations du cent-cinquantenaire du Canada. La SSoE a organisé des équipes de rédaction pour enseignants à l’été 2017 et a produit trois ressources multidisciplinaires portant sur l’éducation pour l’innovation (E41), chacune comportant un modèle du cycle d’innovation, un échantillon des expériences d’apprentissage axées sur l’innovation et des suggestions axées sur les célébrations de l’innovation comme activité culminante. Des stagiaires suivant des cours avec l’équipe professorale de SSoE ont également créé des unités portant sur l’innovation alignées avec les programmes d’études. Par la suite, des équipes d’enseignants ont révisé les unités et des enseignants de divers contextes éducationnels (par exemple, écoles publiques, écoles privées, enseignement à domicile) les ont mises en œuvre et les ont commentées. Le projet E41 a impliqué la collaboration du personnel enseignant de l’université, d’enseignants, de stagiaires et de partenaires communautaires. À partir des données de sondages, les chercheurs ont identifié les avantages et les défis de l’ensemble du processus de développement. Les résultats indiquent que les expériences consistant à poser des questions, à imaginer, à réfléchir et à mettre sur pied les ressources E41 correspondent étroitement aux phases du modèle du cycle de l’innovation. La rétroaction des enseignants a confirmé l’utilité de E41 pour les compétences et les mentalités en innovation chez les étudiants. L’analyse des données du sondage a également fait ressortir la présence, et le besoin, d’un leadership solide, d’un appui souple, de mentalités itératives et de structures organisationnelles organiques.
Mots clés : innovation, éducation, curriculum, interdisciplinaire
 
XMM-Newton Spectra of Intermediate-Mass Black Hole Candidates: Application of a Monte-Carlo Simulated Model
We present a systematic spectral analysis of six ultraluminous X-ray sources
(NGC1313 X-1/X-2, IC342 X-1, HoIX X-1, NGC5408 X-1 and NGC3628 X-1) observed
with XMM-Newton Observatory. These extra-nuclear X-ray sources in nearby
late-type galaxies have been considered as intermediate-mass black hole
candidates. We have performed Monte-Carlo simulations of Comptonized
multi-color black-body accretion disks. This unified and self-consistent
spectral model assumes a spherically symmetric, thermal corona around each disk
and accounts for the radiation transfer in the Comptonization. We find that the
model provides satisfactory fits to the XMM-Newton spectra of thesources. The
characteristic temperatures of the accretion disks (T_in), for example, are in
the range of ~ 0.05-0.3 keV, consistent with the intermediate-mass black hole
interpretation. We find that the black hole mass is typically about a few times
10^3 M_\odot and has an accretion rate ~ 10^{-6} - 10^{-5} M_\odot yr^{-1}. For
the spectra considered here, we find that the commonly used multi-color
black-body accretion disk model with an additive power law component, though
not physical, provides a good mathematical approximation to the Monte-Carlo
simulated model. However, the latter model provides additional constraints on
the properties of the accretion systems, such as the disk inclination angles
and corona optical depths.Comment: 23 pages, 4 figures, 5 tables. ApJ accepted, July 2004 issu
Efficacy and safety of ten day moxifloxacin 400 mg once daily in the treatment of patients with community-acquired pneumonia
AbstractCommunity-acquired pneumonia (CAP) remains a common and serious illness with approximately 2–4 million cases reported annually. Management of CAP is therapeutically challenging due to the increasing prevalence of penicillin- and macrolide-resistant pneumococci and β -lactamase producing Haemophilus influenzae, as well as the increased recognition of ‘atypical’ pathogens, such as Chlamydia pneumoniae and Mycoplasma pneumoniae, and the frequent need for empiric therapy.We aimed to evaluate the safety and efficacy of moxifloxacin in the treatment of patients with CAP. To do this we carried out a prospective, uncontrolled, non-blind, Phase III clinical trial, in 27 U.S. centers. Patients included in the study were over 18 years of age with signs and symptoms of CAP confirmed by evidence of a new or progressive infiltrate on chest radiograph. The intervention used was moxifloxacin 400 mg PO once daily for 10 days.Sputum samples were collected pretherapy for Gram stain and culture for typical organisms. Culture and serological testing for Chlamydia pneumoniae and Mycoplasma pneumoniae was also performed. Susceptibility to moxifloxacin was determined by disk diffusion and MIC. Clinical and bacteriological responses were determined at the end of therapy (0–6 days post-therapy), follow-up (14–35 days post-therapy) and overall (end of therapy plus follow-up). Analyses were performed on both valid for efficacy and intent-to-treat populations. The primary efficacy variable was overall clinical resolution.Of 254 patients enrolled in the Study, 196 patients were included in the efficacy analyses. The majority of patients were male (58%) and Caucasian (85%) with a mean age of 49 years (range: 18 to 85 years). Only 3% of patients were hospitalized pretherapy. The most common pretherapy organisms identified, by culture or serology, in the valid for efficacy population (i.e. 147 organisms among 116 patients), were: Chlamydia pneumoniae (n=63; 54%),Mycoplasma pneumoniae (n=29; 25%), Streptococcus pneumoniae (n=14; 12%) and Haemophilus influenzae (n=13; 10%). End of therapy, follow-up and overall clinical resolution rates for the valid for efficacy population were 94%, 93% and 93%, respectively. The 95% CI for the overall clinical resolution rate was 88·1%, 95·9%. The overall bacteriological response for patients diagnosed by culture or serological criteria, was 91% (95% CI=84%, 96%). For patients who only met serological criteria for infection, the overall bacteriological response was 94% (60/64). Bacterial response rates for the four most commonly isolated pathogens were: 89% (56/63) for C. pneumoniae, 93% (27/29) for M. pneumoniae, 93% (13/14) for S. pneumoniae and 85% (11/13) for H. influenzae. Drug-related adverse events were reported in 33% (85/254) of moxifloxacin-treated patients. Nausea (9%), diarrhea (6%) and dizziness (4%) were the most commonly reported adverse events.Atypical organisms were isolated in high frequency among patients with CAP. Moxifloxacin 400 mg once daily for 10 days was effective and well-tolerated in the treatment of these adult patients with CAP. Moxifloxacin offers an effective treatment alternative for CAP due to both typical and atypical bacterial pathogens
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A study of glycaemic effects following acute anthocyanin-rich blueberry supplementation in healthy young adults
The postprandial response to ingested carbohydrate is recognised as a marker of metabolic health. Postprandial hyperglycaemia is observed in type 2 diabetes mellitus and is a significant risk factor for cardiovascular disease. Cognitive deficits are also associated with type 2 diabetes. Therefore interventions which moderate postprandial glucose profiles are desirable. Here we investigated the impact of anthocyanin-rich wild blueberries on postprandial glucose response. Seventeen healthy young adults consumed a range of doses of freeze-dried wild blueberry powder, in smoothie form, in both sugar-matched and no-added-sugar conditions. Plasma glucose was determined by a capillary sampling method at baseline and at regular intervals up to 2.5 hours postprandially. Blueberries were observed to significantly extend the postprandial glucose response beyond the period observed for a sugar-matched control,
characteristic of a beneficial glycaemic response. Furthermore, blueberries were observed to reduce peak
postprandial glucose levels, although statistical significance was not achieved. The findings suggest a tempering of the postprandial glucose response in the presence of anthocyanin-rich blueberry, and are discussed
with reference to likely glucoregulatory mechanisms of action and their implications for cognitive and type 2 diabetes research
Characterization and comparison of lesions on ornamental sweetpotato 'Blackie', tomato 'Maxifort', interspecific geranium 'Caliente Coral', and bat-faced cuphea 'Tiny Mice'.
Many plant species are prone to physiological disorders in which lesions develop on the leaf tissue. Nomenclature for such lesions has included intumescences, excrescences, neoplasms, galls, genetic tumors, enations, and oedemata. Interchangeably using these terms causes confusion as to whether these names refer to the same or different
disorders. Two of the most commonly used names are oedema and intumescence. The objective of this research was to characterize the development of lesions on ornamental sweetpotato (Ipomoea batatas ‘Blackie’), tomato (Solanum lycopersicum ‘Maxifort’), interspecific hybrid geranium(Pelargonium· ‘CalienteCoral’), and bat-faced cuphea (Cuphea llavea ‘TinyMice’) to determine similarities and differences in morphology and nomenclature among these physiological disorders. Light microscopy was used to characterize differences in cross-sectional height, width, and area of lesions on each species. Additionally, leaf tissue samples were embedded in paraffin, and 10-mm cross-sections were stained with Toluidine blue O and observed using light microscopy to identify specific cell layers involved with lesion development. Field emission scanning electron microscopy (SEM) and digital photography were used to observe the microscopic and macroscopic stages of lesion development, respectively, on each species. The lesions observed on ornamental sweetpotato were significantly greater in height and area than on the other three species, whereas tomato lesions were significantly greater in width. Lesions on ornamental sweetpotato and bat-faced cuphea occurred predominantly on the adaxial surface of the leaf, whereas lesions on geraniumand tomato occurred predominantly on the abaxial surface.With lesions
on tomato, ornamental sweetpotato, and bat-faced cuphea, the epidermis was often subjected to the same hypertrophy apparent in the underlying parenchyma cells, ultimately allowing for greater cell expansion. However, in geranium, the epidermis resisted the expansion of the underlying cells, resulting in the eventual tearing of this tissue layer. Previous research indicates that lesion development on geranium is closely related to water status within the plant and may result in a wound response or provide a means of facilitated gas exchange. On the contrary, development of lesions on
ornamental sweetpotato and tomato is believed to involve light quality. Based on these results and observations, two disorders occur across these species. The term "intumescence’’ should be used when referring to abnormal lesions on ornamental sweetpotato and tomato, and the term ‘‘oedema’’ should be used when referring to lesions on geranium. The term ‘‘intumescence’’ should also be used when referring to bat-faced cuphea lesions resulting from the morphological and anatomical aspects of these lesions closely resembling development on ornamental sweetpotato and tomato. Future research should investigate the role of light quality regarding development on this species
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