929 research outputs found
Esophageal perforation: An uncommon initial manifestation of eosinophilic esophagitis
AbstractEoE-Perforation: Eosinophilic esophagitis (EoE) is commonly observed in children and young adults. Common manifestations of EoE include dysphagia and food impaction in adolescents and adults, whereas children present with failure to thrive, regurgitation, or heartburn and abdominal pain. We describe two patients presenting with esophageal perforation and EoE. Diagnosing perforation promptly is critical to minimize and/or to avoid the multitude of complications resulting from esophageal perforation and to treat EoE because if left untreated, this condition may result in the recurrence of perforation, major morbidity, or rarely death
On elementary extensions in Fuzzy Predicate Logics
10 páginas.-- Comunicación presentada a la International Conference on Information Processing and Management of Uncertainty in Knowledge-Based Systems (IPMU) celebrada en Dortmund (Alemania) del 28 de Junio al 2 de Julio de 2010.Our work is a contribution to the model-theoretic study of
equality-free fuzzy predicate logics. We give a characterization of ele-
mentary equivalence in fuzzy predicate logics using elementary exten-
sions and introduce an strengthening of this notion, the so-called strong
elementary equivalence. Using the method of diagrams developed in [5]
and elementary extensions we present a counterexample to Conjectures
1 and 2 of [8].Research partially funded by the spanish projects CONSOLIDER (CSD2007-
0022), MULOG2 (TIN2007-68005-C04-01) and ARINF (TIN2009-14704-C03-03)
by the ESF Eurocores-LogICCC/MICINN project FFI2008-03126- E/FILO and
by the Generalitat de Catalunya under the grants 2009-SGR 1433 and 1434.Peer reviewe
Returnable transport packaging in developing countries: drivers,barriers and business performance
This study, drawing on natural resource-based view, identifies drivers, barriers and the potential benefits of returnable transport packaging (RTP) – that is, the repeated use of packaging items – and conceptualises RTP as a technology and resource that supports organisational competitiveness. Specifically, it investigates the impact of RTP adoption on business performance, the effects of drivers, barriers and size of organisations. The data collection took place in Nigeria and South Africa. The findings suggest that RTP has a significant positive impact on business performance. Whilst prior studies seem to suggest that shrinkage and attrition are the major problems identified with the usage of RTP, our findings indicate that there are several other barriers affecting RTP adoption and the resultant performance advantage. The results also show that there is an increasing move towards adoption of RTP but some organisations are faced with financial constraints, especially the small and medium size enterprises. In addition, the results show that RTP is largely a ‘sustainability facing’ initiative with adopters motivated primarily by potential environmental, economic, social and operational benefits of adoption
The Influence of Piston Bowl Geometries on In-Cylinder Air Flow in a Direct-Injection (DI) Diesel Engine for Biodiesel Operation / S. Jaichandar, E. James Gunasekaran and A. Gunabalan
Thermal efficiency improvement, fuel consumption and pollutant emissions reduction from biodiesel fueled engines are critical requirements in engine research. In order to achieve these, a rapid and better air-fuel mixing condition is desired. The mixing quality of biodiesel with air can be improved by selecting the best engine design particularly combustion chamber design and injection system parameters. The present work investigates the effect of varying the piston bowl geometry on the air flow characteristics such as swirl velocity, Swirl Ratio (SR), and Turbulent Kinetic Energy (TKE) inside the engine cylinder. The piston’s bowl geometry was modified into several configurations that include Shallow depth combustion chamber (SCC), Toroidal combustion chamber (TCC), Shallow depth reentrant combustion chamber (SRCC) and Toroidal re-entrant combustion chamber (TRCC) from the standard Hemispherical combustion chamber (HCC), without altering the compression ratio of the engine. A commercially available CFD code STAR-CD was used to analyze the in-cylinder flow at different conditions. Flow conditions inside the cylinder were predicted by solving momentum, continuity and energy equations. The results confirmed that the piston bowl geometry had little influence on the in-cylinder flow during the intake stroke and the first part of compression stroke i.e. up to 300oafter suction TDC. However, the piston bowl geometry plays a significant role in the latter stage of the compression stroke i.e. beyond 300oafter suction TDC to compression TDC. The intensity of maximum swirl velocity at the end of compression stroke for TRCC was observed higher as 18.95 m/s and a strong recirculation was observed due to the geometry. Compared to baseline HCC the TRCC had higher, maximum swirl ratio and turbulent kinetic energy by about 28% and 2.14 times respectively. From the analysis of results, it was found that TRCC configuration gives better in-cylinder flows
Nonlinear Protein Degradation and the Function of Genetic Circuits
The functions of most genetic circuits require sufficient degrees of
cooperativity in the circuit components. While mechanisms of cooperativity have
been studied most extensively in the context of transcriptional initiation
control, cooperativity from other processes involved in the operation of the
circuits can also play important roles. In this study, we examine a simple
kinetic source of cooperativity stemming from the nonlinear degradation of
multimeric proteins. Ample experimental evidence suggests that protein subunits
can degrade less rapidly when associated in multimeric complexes, an effect we
refer to as cooperative stability. For dimeric transcription factors, this
effect leads to a concentration-dependence in the degradation rate because
monomers, which are predominant at low concentrations, will be more rapidly
degraded. Thus cooperative stability can effectively widen the accessible range
of protein levels in vivo. Through theoretical analysis of two exemplary
genetic circuits in bacteria, we show that such an increased range is important
for the robust operation of genetic circuits as well as their evolvability. Our
calculations demonstrate that a few-fold difference between the degradation
rate of monomers and dimers can already enhance the function of these circuits
substantially. These results suggest that cooperative stability needs to be
considered explicitly and characterized quantitatively in any systematic
experimental or theoretical study of gene circuits.Comment: 42 pages, 10 figure
Annealing studies and electrical properties of SnS-based solar cells
Thin films of SnS (tin sulphide) were thermally evaporated onto glass and CdS/ITO (cadmium sulphide/indium tin oxide) coated glass substrates and then annealed in vacuum with the aim of optimising them for use in photovoltaic solar cell device structures. The chemical and physical properties of the layers were determined using scanning electron microscopy, energy dispersive x-ray analysis, x-ray diffraction, and transmittance versus wavelength measurements. “Superstrate configuration” devices were also made using indium tin oxide as the transparent conductive oxide, thermally evaporated cadmium sulphide as the buffer layer and evaporated copper/indium as the back contact material. Capacitance-voltage data are given for the fabricated devices. Capacitance- voltage, spectral response and I-V data are given for the fabricated devices
Methyl 1-methyl-3-p-tolyl-1,2,3,3a,4,11c-hexahydrobenzo[f]chromeno[4,3-b]pyrrole-3a-carboxylate
In the title compound, C25H25NO3, the dihydropyran ring adopts a half-chair conformation, whereas the pyrrolidine ring is in a twist conformation. The tolyl group is oriented at an angle of 82.92 (7)° with respect to the napthalene ring system. In the crystal structure, molecules are linked into centrosymmetric dimers by C—H⋯π interactions involving the benzene ring of the tolyl group
A Dynamic Knowledge Management Framework for the High Value Manufacturing Industry
Dynamic Knowledge Management (KM) is a combination of cultural and technological factors, including the cultural factors of people and their motivations, technological factors of content and infrastructure and, where these both come together, interface factors. In this paper a Dynamic KM framework is described in the context of employees being motivated to create profit for their company through product development in high value manufacturing. It is reported how the framework was discussed during a meeting of the collaborating company’s (BAE Systems) project stakeholders. Participants agreed the framework would have most benefit at the start of the product lifecycle before key decisions were made. The framework has been designed to support organisational learning and to reward employees that improve the position of the company in the market place
Hole concentration and phonon renormalization in Ca-doped YBa_2Cu_3O_y (6.76 < y < 7.00)
In order to access the overdoped regime of the YBa_2Cu_3O_y phase diagram, 2%
Ca is substituted for Y in YBa_2Cu_3O_y (y = 7.00,6.93,6.88,6.76). Raman
scattering studies have been carried out on these four single crystals.
Measurements of the superconductivity-induced renormalization in frequency
(Delta \omega) and linewidth (\Delta 2\gamma) of the 340 cm^{-1} B_{1g} phonon
demonstrate that the magnitude of the renormalization is directly related to
the hole concentration (p), and not simply the oxygen content. The changes in
\Delta \omega with p imply that the superconducting gap (\Delta_{max})
decreases monotonically with increasing hole concentration in the overdoped
regime, and \Delta \omega falls to zero in the underdoped regime. The linewidth
renormalization \Delta 2\gamma is negative in the underdoped regime, crossing
over at optimal doping to a positive value in the overdoped state.Comment: 18 pages; 5 figures; submitted to Phys. Rev. B Oct. 24, 2002 (BX8292
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