661 research outputs found
Modified Laplace transformation method and its application to the anharmonic oscillator
We apply a recently proposed approximation method to the evaluation of
non-Gaussian integral and anharmonic oscillator. The method makes use of the
truncated perturbation series by recasting it via the modified Laplace integral
representation. The modification of the Laplace transformation is such that the
upper limit of integration is cut off and an extra term is added for the
compensation. For the non-Gaussian integral, we find that the perturbation
series can give accurate result and the obtained approximation converges to the
exact result in the limit ( denotes the order of perturbation
expansion). In the case of anharmonic oscillator, we show that several order
result yields good approximation of the ground state energy over the entire
parameter space. The large order aspect is also investigated for the anharmonic
oscillator.Comment: 26 pages including tables, Late
"Qué Dios es ese que adoras?": The Construction of Spectatorship in Sor Juana's Loa for The Divine Narcissus
In principle, this loaâs simple plot, the perfect symmetry of its characters, and its religious and political orthodoxy leave little room for the audienceâs agency or imagination. However, a closer examination reveals that, far from offering the kind of straightforward views and statements that one might expect from a work of such apparent simplicity, formal and conceptual elements are interwoven so as to elicit multiple, simultaneous, and conflicting readings. Simply put, the loa is designed to elicit questions, rather than to offer answers. Such questions, in turn, point towards a central position â the readerâs or spectatorâs â around which the entire play gravitates. And yet, this center is constructed on such terms that it becomes a vanishing point: a presence as well as an absence, an inside and an outside, a constituting and a constituted gaze. (MB, Article in English
Experimental Investigation of Shock-Cell Noise Reduction for Single Stream Nozzles in Simulated Flight
Seven single stream model nozzles were tested in the Anechoic Free-Jet Acoustic Test Facility to evaluate the effectiveness of convergent divergent (C-D) flowpaths in the reduction of shock-cell noise under both static and mulated flight conditions. The test nozzles included a baseline convergent circular nozzle, a C-D circular nozzle, a convergent annular plug nozzle, a C-D annular plug nozzle, a convergent multi-element suppressor plug nozzle, and a C-D multi-element suppressor plug nozzle. Diagnostic flow visualization with a shadowgraph and aerodynamic plume measurements with a laser velocimeter were performed with the test nozzles. A theory of shock-cell noise for annular plug nozzles with shock-cells in the vicinity of the plug was developed. The benefit of these C-D nozzles was observed over a broad range of pressure ratiosin the vicinity of their design conditions. At the C-D design condition, the C-D annual nozzle was found to be free of shock-cells on the plug
A systematic review of criteria used to report complications in soft tissue and oncologic surgical clinical research studies in dogs and cats.
ObjectiveTo evaluate reporting of surgical complications and other adverse events in clinical research articles describing soft tissue and oncologic surgery in dogs and cats.Study designSystematic literature review.SampleEnglish-language articles describing soft tissue and oncologic surgeries in client-owned dogs and cats published in peer-reviewed journals from 2013 to 2016.MethodsCAB, AGRICOLA, and MEDLINE databases were searched for eligible articles. Article characteristics relevant to complications were abstracted and summarized, including reported events, definitions, criteria used to classify events according to severity and time frame, and relevant citations.ResultsOne hundred fifty-one articles involving 10â522 animals were included. Canine retrospective case series of dogs predominated. Ninety-two percent of articles mentioned complications in study results, but only 7.3% defined the term complication. Articles commonly described complications according to time frame and severity, but terminology and classification criteria were highly variable, conflicting between studies, or not provided. Most (58%) reported complications could have been graded with a published veterinary adverse event classification scheme, although common intraoperative complications were notable exceptions.ConclusionDefinitions and criteria used to classify and report soft tissue and oncologic surgical complications are often absent, incomplete, or contradictory among studies.Clinical significanceLack of consistent terminology contributes to inadequate communication of important information about surgical complications. Standardization of terminology and consistency in severity scoring will improve comparative evaluation of clinical research results
Thermal behaviour of rebars and steel deck components of composite slabs under natural fire
Most of the studies involving composite slabs under fire follow the standard fire scenario described by the ISO 834 curve, disregarding the cooling-phase. However, recent studies show that this phase is equally important, as it can lead to the collapse of the structure. Therefore, the present research carried out a parametric study, using numerical models, validated through experimental tests, to evaluate the thermal behaviour of the composite slabs components under natural fire. The results showed that the maximum temperatures in the reinforcement bars occur during the cooling-phase, reaching temperatures up to 300% higher than at the heating-phase, on the steel deck occur at the end of heating, and that the concrete thickness above the steel deck influences the temperature of these components. Also, during the cooling-phase, a âheat bubbleâ effect is observed on the ribs of the composite slabs, where the reinforcement bars are normally placed. These results highlight the importance of considering different natural fire scenarios, in the structural performance and safety of composite slabs, since during the cooling-phase there is still heat transfer between the elements, which can lead to slab failure. New parameters are proposed to find the temperature of each component for different fire ratings
Free jet feasibility study of a thermal acoustic shield concept for AST/VCE application: Single stream nozzles
A technology base for the thermal acoustic shield concept as a noise suppression device for single stream exhaust nozzles was developed. Acoustic data for 314 test points for 9 scale model nozzle configurations were obtained. Five of these configurations employed an unsuppressed annular plug core jet and the remaining four nozzles employed a 32 chute suppressor core nozzle. Influence of simulated flight and selected geometric and aerodynamic flow variables on the acoustic behavior of the thermal acoustic shield was determined. Laser velocimeter and aerodynamic measurements were employed to yield valuable diagnostic information regarding the flow field characteristics of these nozzles. An existing theoretical aeroacoustic prediction method was modified to predict the acoustic characteristics of partial thermal acoustic shields
On the relationship between sloppiness and identifiability
25 pĂĄginas, 11 figuras, 2 tablasDynamic models of biochemical networks are often formulated as sets of non-linear ordinary differential equations, whose states are the concentrations or abundances of the network components. They typically have a large number of kinetic parameters, which must be determined by calibrating the model with experimental data. In recent years it has been suggested that dynamic systems biology models are universally sloppy, meaning that the values of some parameters can be perturbed by several orders of magnitude without causing significant changes in the model output. This observation has prompted calls for focusing on model predictions rather than on parameters. In this work we examine the concept of sloppiness, investigating its links with the long-established notions of structural and practical identifiability. By analysing a set of case studies we show that sloppiness is not equivalent to lack of identifiability, and that sloppy models can be identifiable. Thus, using sloppiness to draw conclusions about the possibility of estimating parameter values can be misleading. Instead, structural and practical identifiability analyses are better tools for assessing the confidence in parameter estimates. Furthermore, we show that, when designing new experiments to decrease parametric uncertainty, designs that optimize practical identifiability criteria are more informative than those that minimize sloppinessThis project has received funding from the European Unionâs Horizon 2020 research and innovation programme under grant agreement No 686282 (âCANPATHPROâ) and from the Spanish government (MINECO) and the European Regional Development Fund (ERDF) through the projects âSYNBIOFACTORYâ (grant number DPI2014-55276-C5-2-R), and âIMPROWINEâ (grant number AGL2015-67504-C3-2-R)N
Aberrant migration and surgical removal of a heartworm (Dirofilaria immitis) from the femoral artery of a cat.
A cat was evaluated for an acute-onset of right pelvic limb paresis. Thoracic radiographs revealed normal cardiac size and tortuous pulmonary arteries. Abdominal ultrasound identified a heartworm (HW) extending from the caudal abdominal aorta into the right external iliac artery and right femoral artery. The cat was HW-antigen positive. Echocardiography revealed a HW within the right branch of the main pulmonary artery and evidence of pulmonary hypertension. An agitated-saline contrast echocardiogram revealed a small right to left intracardiac shunt at the level of the atria. Surgical removal of the HW was performed with no substantial postoperative complications. There was return of blood flow and improved motor function to the limb. The cat remains mildly paretic on the affected limb with no other clinical signs
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