3,614 research outputs found
Assessment of free-living nitrogen fixing microorganisms for commercial nitrogen fixation
Ammonia production by Klebsiella pneumoniae is not economical with present strains and improving nitrogen fixation to its theoretical limits in this organism is not sufficient to achieve economic viability. Because the value of both the hydrogen produced by this organism and the methane value of the carbon source required greatly exceed the value of the ammonia formed, ammonia (fixed nitrogen) should be considered the by-product. The production of hydrogen by KLEBSIELLA or other anaerobic nitrogen fixers should receive additional study, because the activity of nitrogenase offers a significant improvement in hydrogen production. The production of fixed nitrogen in the form of cell mass by Azotobacter is also uneconomical and the methane value of the carbon substrate exceeds the value of the nitrogen fixed. Parametric studies indicate that as efficiencies approach the theoretical limits the economics may become competitive. The use of nif-derepressed microorganisms, particularly blue-green algae, may have significant potential for in situ fertilization in the environment
The development of an unconventional food regeneration process: Quantifying the nutritional components of a model methylotrophic yeast
A hybrid chemical/biological approach to unconventional food regeneration is discussed. Carbon dioxide and water, the major wastes of human metabolism would be converted to methanol by one of several physiochemical processes available (thermal, photocatalytic, etc.). Methanol is then used to supply carbon and energy for the culture of microorganisms which in turn produce biological useful basic food stuffs for human nutrition. Our work has focused on increasing the carbohydrate levels of a candidate methylotrophic yeast to more nearly coincide with human nutritional requirements. Yeasts were chosen due to their high carbohydrate levels compared to bacteria and their present familiarity in the human diet. The initial candidate yeast studied was a thermotolerant strain of Hansenula polymor pha, DL-1. The quantitative results that permit an evaluation of the overall efficiency in hybrid chemical/biological food production schemes are discussed. A preliminary evaluation of the overall efficiency of such schemes is also discussed
Comparison of Parent-Child Interactions in Abusive and Control Families: An Observational Study
This study sought to identify differences in caregiver-child interactions between caregivers with and without prior reports of child physical abuse. Data for the abuse group were made available for secondary analyses by the National Archive for Child Abuse and Neglect via Cornell University. Data for the comparison group were collected for a previous study at West Virginia University. For both studies, caregiver-child dyads participated in a 5---minute, videotaped observation in a situation in which the parent had to exert moderate control over the child. Data that had been coded using the Dyadic Parent---Child Interaction Coding System (Eyberg, et al., 1994; Eyberg, et al., 2005) were compared in 70 caregiver-child dyads. Groups were similar with regard to child behavior, parent age, child gender, parental education level, caregiver marital status, and relation of parent to child. Analyses were conducted with both the sample of 70 dyads, in which children in the abuse group were older, and with a subsample of 41 dyads, in which all children were 4- to 5-years-old and significantly more caregivers in the abuse group were male. Race was considered in both sets of analyses. Results with both samples revealed that, over and above demographic differences, parents in the abuse group talked significantly more and, after additionally controlling for total talk, gave significantly less praise. These results inform parental fitness examinations, but observations should be examined within a broader assessment. Limitations of this study include comparison of two pre-existing samples with some procedural and sample differences. Future research should consider demographic differences when examining caregiver-child differences in abusive samples and attempt to include fathers
Cockpit Ocular Recording System (CORS)
The overall goal was the development of a Cockpit Ocular Recording System (CORS). Four tasks were used: (1) the development of the system; (2) the experimentation and improvement of the system; (3) demonstrations of the working system; and (4) system documentation. Overall, the prototype represents a workable and flexibly designed CORS system. For the most part, the hardware use for the prototype system is off-the-shelf. All of the following software was developed specifically: (1) setup software that the user specifies the cockpit configuration and identifies possible areas in which the pilot will look; (2) sensing software which integrates the 60 Hz data from the oculometer and heat orientation sensing unit; (3) processing software which applies a spatiotemporal filter to the lookpoint data to determine fixation/dwell positions; (4) data recording output routines; and (5) playback software which allows the user to retrieve and analyze the data. Several experiments were performed to verify the system accuracy and quantify system deficiencies. These tests resulted in recommendations for any future system that might be constructed
An Optimal Calibration Procedure for a TELEMAC-2D Model of the Eastern Coast of Ireland
Water Qualit
Exponentially small heteroclinic breakdown in the generic Hopf-zero singularity
In this paper we prove the breakdown of an heteroclinic connection in the
analytic versal unfoldings of the generic Hopf-Zero singularity in an open set
of the parameter space. This heteroclinic orbit appears at any order if one
performs the normal form around the origin, therefore it is a phenomenon
"beyond all orders". In this paper we provide a formula for the distance
between the corresponding stable and unstable one dimensional manifolds which
is given by an exponentially small function in the perturbation parameter. Our
result applies both for conservative and dissipative unfoldings
EBM Resources Decision Tree
The EBM Resources Decision Tree is a mobile-friendly website designed for for a month-long problem-based learning (PBL) course for pre-clinical medical students. The website sought to improve the range and quality of sources used by students in the PBL course. A secondary objective was to offer a website to encourage the use of evidence-based medicine tools in clinical care
Developing and sustaining specialist and advanced practice roles in nursing and midwifery: A discourse on enablers and barriers
Aims and objectives
To collate, synthesise and discuss published evidence and expert professional opinion on enablers and barriers to the development and sustainability of specialist and advanced practice roles in nursing and midwifery. Background
Expanded practice is a response to population health needs, healthcare costs and practitioners’ willingness to expand their scope of practice through enhanced responsibility, accountability and professional autonomy. Design
This discursive paper is based on a rapid review of literature on enablers and barriers to the development and sustainability of specialist and advanced practice roles and is part of a wider policy analysis. Methods
We analysed and synthesised of 36 research articles, reviews and discussion papers on enablers and barriers in the development and sustainability of expanded practice roles. Results
Several factors enable role expansion, including: role clarity; credentialing and endorsement; availability of education for expanded roles; individual practitioners’ dispositions towards role expansion; support from peers, other professionals and the work organisation; and costs. Where limited or absent, these same factors can constrain role expansion. Conclusions
Enabling nurses and midwives to practice to their full scope of education and expertise is a global challenge for disciplinary leadership, a national challenge for professional regulation and a local challenge for employers and individual clinicians. These challenges need to be addressed through multistakeholder coordinated efforts at these four levels. Relevance to clinical practice
This discursive paper synthesises empirical evidence and expert professional opinion on the factors that enable or hinder the development and sustainability of specialist and advanced practice roles. Providing a critical appraisal of current knowledge, it provides a reference source for disciplinary debate and policy development regarding the nursing and midwifery resource and informs clinicians of the myriad issues that can impact on their capacity to expand their scope of practice
DNA species surveillance: Monitoring bushmeat poaching and trading in Kenya using partial cytochrome b gene
DNA species identification has applications in such areas as forensic science, systematics, conservation genetics and agriculture. One key anthropogenic activity threatening large wildlife fauna is illegal exploitation. In Kenya, species identification of raw and processed meat products remains a constraint to effective enforcement of illegal trade in game meat (bushmeat) and products. We tested the reliability of a 321 bp mitochondrial cytochrome b (cyt b) region as a species identification tool for application in wildlife forensics. Query sequences were generated from known specimens of 14 Eastern African wildlife species, 13 representing commonly poached ungulates, and three domesticated species. These were compared, using Basic Local Alignment Search Tool (BLAST) algorithm, with NCBI GenBank reference sequences for species identity. These query sequences were subsequently deposited on Genbank. They represent a contribution to a diagnostic internal East African Wildlife reference cyt b database. The test species comprised: Cape buffalo, bushbuck, Guenther’s dik-dik, common duiker, common eland, Grant’s gazelle, hartebeest, impala, lesser kudu, plains zebra, Thomson’s gazelle, common warthog, wildebeest, Maasai ostrich, cattle, goat and sheep. Additionally, cooked beef and pork samples were analyzed. The results show that, when conspecific sequences were available in the database, species discrimination was 100%. Phylogeny clustering of the species by maximum likelihood supported the species determination by BLAST. The second part of the study carried out a preliminary survey of the prevalence of illegal game meat sold in the dispersal area of Tsavo National Park, Kenya. Sixty two raw meat samples were randomly collected from small roadside retail outlets along the Nairobi-Mombasa highway (A109), a major transnational highway that transverses Tsavo National Park. The results indicate a 9.7% (n = 6) illegal game meat sale, comprising five Guenther’s dik-diks and a Beisa oryx. A 2 km radius hotspot, with 83% (n = 5) of the bushmeat sales was identified just south of Tsavo East National Park.Key words: East Africa, Kenya, bushmeat, poaching, wildlife conservation, species identification, mitochondrial cytochrome b gene
New Approach to Nonlinear Dynamics of Fullerenes and Fullerites
New type of nonlinear (anharmonic) excitations -- bushes of vibrational modes
-- in physical systems with point or space symmetry are discussed. All infrared
active and Raman active bushes for C60 fulerene are found by means of special
group-theoretical methods.Comment: LaTeX, 8 pages, to be published in Fizika Tverdogo Tela, 200
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