788 research outputs found

    Polarographic study of cadmium 5-hydroxy 2-(hydroxymethyl) 4H-pyran-4-one complex

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    A polarographic study was performed on the products formed in the interaction of cadmium (II) with a 5-hydroxy 2-(hydroxymethyl) 4H-Pyran-4-one, using varying conditions of pH, supporting electrolytes, and concentrations. Measurements using the differential pulse method show that cadmium (II) exhibits a molar combining ratio of complexing agents to cation ranging from 1 to 1 to 3 to 1 depending on the pH and the supporting electrolyte employed

    Motivational Patterns Of Enrollees In University-Based Executive And Professional Education Courses

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    The purpose of this paper is to begin an exploration into high-skills lifelong learning in the field of business and management, referred to as executive and professional education (EPE).  Several additional undertakings were necessary, including: discovering methods of valuing knowledge to a region, state or country, and establishing why participants in EPE programs enroll in them. To support this inquiry two research questions were developed, as follows:  1. What are the components of relevant EPE? 2. What motivates participants to take part in EPE? An exploratory case study was written exploring the intricacies of developing a successful EPE department.  This exploratory case study served as a basis for developing a survey, administered to participants in EPE to determine reasons for their participation.  This final survey was conducted in the classroom. The researchers believe that the findings and conclusions will be of value to practitioners involved in EPE, as well as to academics studying this area of business education.  This research exercise has assisted the researchers in being more effective in managing and developing EPE within their own university.  As professions and skills are made obsolete in the knowledge economy the need for continued high level lifelong learning becomes increasing important to the sustainability and viability of local, regional, state and national economies

    Resonance energy transfer: The unified theory revisited

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    Resonanceenergy transfer (RET) is the principal mechanism for the intermolecular or intramolecular redistribution of electronic energy following molecular excitation. In terms of fundamental quantum interactions, the process is properly described in terms of a virtual photon transit between the pre-excited donor and a lower energy (usually ground-state) acceptor. The detailed quantum amplitude for RET is calculated by molecular quantum electrodynamical techniques with the observable, the transfer rate, derived via application of the Fermi golden rule. In the treatment reported here, recently devised state-sequence techniques and a novel calculational protocol is applied to RET and shown to circumvent problems associated with the usual method. The second-rank tensor describing virtual photon behavior evolves from a Green’s function solution to the Helmholtz equation, and special functions are employed to realize the coupling tensor. The method is used to derive a new result for energy transfer systems sensitive to both magnetic- and electric-dipole transitions. The ensuing result is compared to that of pure electric-dipole–electric-dipole coupling and is analyzed with regard to acceptable transfer separations. Systems are proposed where the electric-dipole–magnetic-dipole term is the leading contribution to the overall rate

    Investigating a Multimodal Intervention for Children with Limited Expressive Vocabularies Associated with Autism

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    This is the author's accepted manuscript. The original is available at http://www.asha.org/default.htmPurpose: To investigate a new intervention package aimed at increasing expressive word learning by school-age children with autism who have limited expressive vocabularies. This pilot investigation was intended to show proof of concept. Method: Ten children between the ages of 6-10 years with educational diagnoses of autism and limited expressive vocabularies at the outset of the study participated. A multimodal intervention composed of speech sound practice and AAC was used to teach individualized vocabulary words that were selected based on initial speech sound repertoires and principles of phonotactic probability and neighborhood density. A multiple-probe design was used to evaluate learning outcomes. Results: Five children showed gains in spoken- word learning across successive word sets (High Responders). Five children did not meet learning criteria (Low Responders). Comparisons of behaviors measured prior to intervention indicated that High Responders had relatively higher skills in receptive language, prelinguistic communication, vocal/verbal imitation, adaptive behavior and consonant productions. Conclusions: The intervention package holds promise for improving spoken word productions for some children with autism who have limited expressive vocabularies. Further research is needed to better describe who may most benefit from this approach as well as investigate generalized benefits to untaught contexts and targets

    Iatrogenic Spinal Cord Injury Resulting From Cervical Spine Surgery.

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    STUDY DESIGN: Retrospective cohort study of prospectively collected data. OBJECTIVE: To examine the incidence of iatrogenic spinal cord injury following elective cervical spine surgery. METHODS: A retrospective multicenter case series study involving 21 high-volume surgical centers from the AOSpine North America Clinical Research Network was conducted. Medical records for 17 625 patients who received cervical spine surgery (levels from C2 to C7) between January 1, 2005, and December 31, 2011, were reviewed to identify occurrence of iatrogenic spinal cord injury. RESULTS: In total, 3 cases of iatrogenic spinal cord injury following cervical spine surgery were identified. Institutional incidence rates ranged from 0.0% to 0.24%. Of the 3 patients with quadriplegia, one underwent anterior-only surgery with 2-level cervical corpectomy, one underwent anterior surgery with corpectomy in addition to posterior surgery, and one underwent posterior decompression and fusion surgery alone. One patient had complete neurologic recovery, one partially recovered, and one did not recover motor function. CONCLUSION: Iatrogenic spinal cord injury following cervical spine surgery is a rare and devastating adverse event. No standard protocol exists that can guarantee prevention of this complication, and there is a lack of consensus regarding evaluation and treatment when it does occur. Emergent imaging with magnetic resonance imaging or computed tomography myelography to evaluate for compressive etiology or malpositioned instrumentation and avoidance of hypotension should be performed in cases of intraoperative and postoperative spinal cord injury

    Caprock integrity and public perception studies of carbon storage in depleted hydrocarbon reservoirs

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    Capture and subsurface storage of CO2 is widely viewed as being a necessary component of any strategy to minimise and control the continued increase in average global temperatures. Existing oil and gas reservoirs can be re-used for carbon storage, providing a substantial fraction of the vast amounts of subsurface storage space that will be required for the implementation of carbon storage at an industrial scale. Carbon capture and storage (CCS) in depleted reservoirs aims to ensure subsurface containment, both to satisfy safety considerations, and to provide confidence that the containment will continue over the necessary timescales. Other technical issues that need to be addressed include the risk of unintended subsurface events, such as induced seismicity. Minimisation of these risks is key to building confidence in CCS technology, both in relation to financing/liability, and the development and maintenance of public acceptance. These factors may be of particular importance with regard to CCS projects involving depleted hydrocarbon reservoirs, where the mechanical effects of production activities must also be considered. Given the importance of caprock behaviour in this context, several previously published geomechanical caprock studies of depleted hydrocarbon reservoirs are identified and reviewed, comprising experimental and numerical studies of fourteen CCS pilot sites in depleted hydrocarbon reservoirs, in seven countries (Algeria, Australia, Finland, France, Germany, Netherlands, Norway, UK). Particular emphasis is placed on the amount and types of data collected, the mathematical methods and codes used to conduct geomechanical analysis, and the relationship between geomechanical aspects and public perception. Sound geomechanical assessment, acting to help minimise operational and financial/liability risks, and the careful recognition of the impact of public perception are two key factors that can contribute to the development of a successful CCS project in a depleted hydrocarbon reservoir

    The in vitro synthesis and processing of the branched-chain amino acid binding proteins

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    The synthesis of the leucine-specific and LIV-binding proteins was examined in vitro in a coupled transcription/translation system using the hybrid plasmids pOX7 and pOX13 as templates. Plasmid pOX7 contains the livK gene coding for the leucine-specific binding protein, and pOX13 contains the liv J gene coding for the LIV-binding protein. Both binding proteins were synthesized in vitro as precursor forms with molecular weights approximately 2,500 greater than their respective mature forms. Conversion of the precursor forms to their mature forms occurred during post-translational incubation following synthesis in the presence of membrane. The precursor of the LIV-binding protein was processed more rapidly than the leucine-specific binding protein precursor. Processing activity could be removed from the in vitro synthesis system by centrifugation, suggesting that the processing activity was membrane associated. Restoration of post-translational processing activity was achieved by adding inside-out membrane vesicles to membrane-depleted reaction mixtures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38208/1/400140305_ftp.pd

    Regulation of high-affinity leucine transport in escherichia coli

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    Leucine is transported into E coli by two osmotic shock-sensitive, high-affinity systems (LIV-I and leucine-specific systems) and one membrane bound, low-affinity system (LIV-II). Expression of the high-affinity transport systems is altered by mutations in liv R and 1st R , genes for negatively acting regulatory elements, and by mutations in rho , the gene for transcription termination. All four genes for high-affinity leucine transport ( livJ, livK, livH , and livG ) are closely linked and have been cloned on a plasmid vector, pOX1. Several subcloned fragments of this plasmid have been prepared and used in complementation and regulation studies. The results of these studies suggest that livJ and livK are separated by approximately one kilobase and give a gene order of livJ–livK–livH. livJ and livK appear to be regulated in an interdependent fashion; livK is expressed maximally when the livJ gene is inactivated by mutation or deletion. The results support the existence of separate promoters for the livJ and livK genes. The effects of mutations in the rho and livR genes are additive on one another and therefore appear to be involved in independent regulatory mechanisms. Mutations in the rho gene affect both the LIV-I and leucinespecific transport systems by increasing the expression of livJ and livK , genes for the LIV-specific and leucine-specific binding proteins, respectively.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38209/1/400140410_ftp.pd

    An Experimental Evaluation of Rate Adaptation for Multi-Antenna Systems

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    Abstract—Increasingly wireless networks use multi-antenna nodes as in IEEE 802.11n and 802.16. The Physical layer (PHY) in such systems may use the antennas to provide multiple streams of data (spatial multiplexing) or to increase the robustness of fewer streams. These physical layers also provide support for sending packets at different rates by changing the modulation and coding of transmissions. Rate adaptation is the problem of choosing the best transmission mode for the current channel and in these systems requires choosing both the level of spatial multiplexing and the modulation and coding. Hydra is an experimental wireless network node prototype in which both the MAC and PHY are highly programmable. Hydra’s PHY is essentially the 802.11n PHY, and currently supports two antennas and the same modulations and codings as 802.11n. Because of limitations of our hardware platform, th
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