196,346 research outputs found
Conserved visual capacity of rats under red light
No full textRecent studies examine the behavioral capacities of rats and mice with and without visual input, and the neuronal mechanisms underlying such capacities. These animals are assumed to be functionally blind under red light, an assumption that might originate in the fact that they are dichromats who possess ultraviolet and green cones, but not red cones. But the inability to see red as a color does not necessarily rule out form vision based on red light absorption. We measured Long-Evans rats’ capacity for visual form discrimination under red light of various wavelength bands. Upon viewing a black and white grating, they had to distinguish between two categories of orientation: horizontal and vertical. Psychometric curves plotting judged orientation versus angle demonstrate the conserved visual capacity of rats under red light. Investigations aiming to explore rodent physiological and behavioral functions in the absence of visual input should not assume red-light blindness
Elastic–plastic frictionless indentation analysis of a functionally graded vitreous enameled steel plate by a rigid spherical indenter
No full textElastic-plastic frictionless indentation of a functionally graded (FG) vitreous enameled steel plate with finite dimensions by a rigid spherical punch is studied in this paper. The problem is studied both experimentally and by using ABAQUS finite element package. The results obtained from ABAQUS simulations are compared to experimental results to check the validity of the ABAQUS model. In the simulations, the plastic deformation of the constituting phases of the plate is taken into account by using a volume fraction based model called TTO model. The validity of the TTO estimation of the modulus of elasticity is examined and verified by nano-indentation technique. The ABAQUS model is used to conduct a parametric analysis on the effect of parameters such as plate dimensions and thickness, indenter diameter and material properties distribution on the force-indentations curves of the plate and stress distribution underneath the punch. The simulations show that increasing the overall stiffness of the graded medium increases the stress mismatch at the interface of the plate constituting layers regardless of the layers thicknesses. In addition, the acquired results illustrated that for plates with similar thickness and material property distribution, changing the span does not affect the force-indentation curves
Delamination evaluation of composite laminates with different interface fiber orientations using acoustic emission features and micro visualization
No full textThis study aims to investigate the sequence of initiation and evolution of different damage mechanisms during the DCB standard test procedure on specimens with different interface fiber orientation using Acoustic Emission (AE) data analysis and microscopic imaging methods. For this purpose, a series of experiments based on standard ASTM D5528 were performed on 24 layer glass epoxy multidirectional specimens with ±θ/05 As As layup, in which θ is 0. 30. 45 and 60. The acoustic data were then acquired with two AE sensors and the whole test procedure was observed by two digital cameras, which were focused on specimen edges. The results show that the initiation and evolution process of matrix cracking as the first activated damage mechanism greatly depends on the interface fiber orientation. Also, load-displacement curves and AE data can be well correlated with microscopic observation in all stages of damage initiation, evolution and propagation. Although the standard nonlinear point as crack initiation onset predict an equal fracture energy for all cases, however AE analyses and microscopic observations show early damage initiation and evolution in 45 and 60-degree interfaces
IS200 fingerprinting of Salmonella enterica serotype Abortusovis strains isolated in Iran
No full textSalmonella enterica serovar Abortusovis is one of the most common pathogens responsible for abortion in sheep. In Iran, the spread of Abortusovis is highly dependent on the nomadic life style. In this study we performed IS200 fingerprinting to identify the clonal lines circulating in Iran. All the isolates contained 4 or 5 copies of the transposon and could be classified in 4 genotypes. A single genotype was highly prevalent and very likely it has circulated in Iran since 1970. All the isolates showed a high degree of relatedness
Process Engineering for Low-Temperature Carbon-Based Perovskite Solar Modules
No full text<p>In less than a decade, Perovskite solar cell (PSC) technology has gained high efficiency and broad attention because of its key enabling physical and morphological features. One of the main obstacles to PSC industrialization and commercialization is managed with the demonstration of stable devices by adopting low-cost, reliable materials and fabrication process methods. Here, we report a Perovskite solar module based on a low-temperature carbon electrode. The full process was performed in ambient air and engineered by printing techniques.</p>
Clonal diversity of Salmonella enterica serotype Typhi isolated from patients with typhoid fever in Tehran
No full textLeptin Receptor mRNA in Bull Ejaculated Spermatozoa
No full textLeptin is a potential satiety factor and plays an important role in both metabolism and reproduction; both leptin and its receptor (Ob-R) have been detected in human spermatozoa, thus suggesting leptin involvement in male gamete physiology. This experiment was designed to investigate leptin receptor [the long isoform (Ob-Rb)] mRNA in bull ejaculated spermatozoa by RT-PCR and southern hybridization. Total RNA was isolated from ejaculated spermatozoa and purified by different methods. Although the concentrations of RNA determined by all methods (except SDS/Proteinase K, lowest amount of RNA recovery) were similar, ethidium bromide staining was only detectable in lanes containing the samples isolated by sodium dodecyl sulphate (SDS) and SDS/citric acid extraction which produced higher RNA concentration. Ob-Rb mRNA was detected in all samples using southern hybridization after RT-PCR; it was shown only in three of them by RT-PCR. We may conclude that Ob-Rb mRNA is present in bull spermatozoa and leptin perhaps exerts physiological effects, as already demonstrated in humans and pigs
Techno-economical Analysis of Rooftop Grid-connected PV Dairy Farms; Case Study of Urmia University Dairy Farm
No full textThe global trends indicate a growing commitment to renewable energy development because of declining fossil fuels and environmental threats. Moreover, the global demographic growth coupled with rising demands for food has escalated the rate of energy consumption in food section. This study aims to investigate the techno-economic impacts of a grid-connected rooftop PV plan applied for a educational dairy farm in Urmia university, with total estimated annual electrical energy consumption of 18,283 kWh, located at the north west part of Iran. Based on the current feed-in tariff and tremendously low electricity price in agriculture section in Iran, the plants with size ranged from 14.4 to 19.7 kWp (initial investment ranged from 26,000 to 36,000 USD) would be satisfied economically
Automated Solution of Partial Differential Equations with Discontinuities using the Partition of Unity Method
No full textAlthough computers were invented to automate tedious and error-prone tasks, computer programming is a tedious and error-prone task itself. This is a well-known paradox in the field of computational mathematical modelling. Recently, automatic code generation has been proposed to solve this paradox. In this approach, a required code to model physical problems is generated by compiling an input file which mimics mathematical notations. In this thesis, the automatic code generation has been extended to support developing models for problems with discontinuities. Examples of this kind of problems in real world are cracks, slip planes and singularities in materials as well as phase interfaces in multiphase flows. This framework is designed in the context of the FEniCS project, an open source project in the Automation of Computational Mathematical Modelling (ACMM). The automated framework has been implemented in two packages which are licensed as open source software and they can be downloaded for free. - A compiler (in Python) for generating C++ low-level code to model discontinuities from the high-level code close to mathematical notations https://launchpad.net/ffc-pum - A solver library (in C++) to use the generated code from the PUM compiler in combination with other reusable components of DOLFIN to model discontinuities https://launchpad.net/dolfin-pum This framework provides required tools and functionalities to fast and efficient development of the partition of unity models for physical problems represented by partial differential equations in domains with discontinuity surfaces. Developing such models especially for coupled problems, in which different combinations of continuous/discontinuous spaces may exist, is a time consuming and difficult task. Using the automated framework moves the focus from implementation to modeling. Therefore, different models can be simulated and tested quickly with minimum reworks. The examples, presented in this thesis, were limited to non-branching discontinuity surfaces with the Heaviside enrichment function. A novel algorithm is also proposed to keep track of three-dimensional propagating surfaces. However, the solver library is designed such that it can be relatively easily extended to support other types of problems.Structural EngineeringCivil Engineering and Geoscience
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
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