Miracle-dz/UniFAR-FTUs huggingface dataset:
The minimal flow unit in near-wall turbulence

Direct numerical simulations of unsteady channel flow were performed at low to moderate Reynolds numbers on computational boxes chosen small enough so that the flow consists of a doubly periodic (in x and z) array of identical structures. The goal is to isolate the basic flow unit, to study its morphology and dynamics, and to evaluate its contribution to turbulence in fully developed channels. For boxes wider than approximately 100 wall units in the spanwise direction, the flow is turbulent and the low-order turbulence statistics are in good agreement with experiments in the near-wall region. For a narrow range of widths below that threshold, the flow near only one wall remains turbulent, but its statistics are still in fairly good agreement with experimental data when scaled with the local wall stress. For narrower boxes only laminar solutions are found. In all cases, the elementary box contains a single low-velocity streak, consisting of a longitudinal strip on which a thin layer of spanwise vorticity is lifted away from the wall. A fundamental period of intermittency for the regeneration of turbulence is identified, and that process is observed to consist of the wrapping of the wall-layer vorticity around a single inclined longitudinal vortex.
Entry Costs, Task Variety, and Skill Flexibility: A Simple Theory of (Top) Income Skewness

Abstract This paper develops a simple model that provides a unified explanation for both an increase in below-top skewness and a much larger increase in within-top skewness of wage income distribution. It relies on a single mechanism based on the fixed costs of firm entry. A decrease in entry costs increases the variety of goods/tasks and thus the demand for higher-skilled workers who are more flexible in handling a variety of tasks, which increases both types of skewness. Differences in flexibility are modeled as differences in the fixed labor setup costs required to handle a given number of tasks. Our numerical experiments in a calibrated model show that a decrease in entry costs – entry deregulation – can be a quantitatively important source of both the increase in below-top skewness and the much larger increase in within-top skewness observed in the U.S. Moreover, the experiments imply that the observed differences in entry deregulation can cause significant differences in the top skewness across countries that have similar technological change. This can provide an answer to Piketty and Saez’s (2006) question: Why have top wages surged in English speaking countries in recent decades but not in continental Europe or Japan, which have gone through similar technological change?
EFFECTS OF MAGNETIC FIELD AND INCLINED LOAD IN MICROPOLAR THERMOELASTIC MEDIUM POSSESSING CUBIC SYMMETRY UNDER THREE THEORIES

Mohamed I. A. Othmana;b , Kh. Lotfya, R. M. Farouka;c (a) Department of Mathematics, Faculty of Science, Zagazig University, P.O. Box 44519, Zagazig, Egypt. (b) Department of mathematics, Faculty of Science, AL-Dawadmi, King Saud University, Kingdom of Saudi Arabia, P.O. Box 18, AL-Dawadmi 11911. (c) Department of Computer Science, Faculty of Science, AL-Dawadmi, King Saud University, Kingdom of Saudi Arabia, P.O. Box 18, AL-Dawadmi 11911. |||||||||||||||||||||||||||||||Abstract A model of the equations of two-dimensional problems is studied in a half space, whose surface in a medium free of micropolar thermoelastic possesses cubic symmetry as a result of inclined load. There acts an initial magnetic eld parallel to the plane boundary of the half-space. The inclined load is assumed to be a linear combination of a normal load and a tangential load. The formulation is performed in the context of the Lord-Shulman and Green-Lindsay theories, as well as the classical dynamical coupled theory. Comparisons are made with the results in the presence of a magnetic.
Computational homogenization for adhesive and cohesive failure in quasi‐brittle solids

A computational multiscale framework is proposed that incorporates microstructural behaviour in a macroscale discrete fracture model. Homogenization procedures are derived for both adhesive and cohesive failure on the macroscale and are implemented in an FE2‐setting. The most important feature of the homogenization procedure is that it implicitly defines a traction‐opening relation for the macroscale fracture model. The representativeness of the micro models is studied using a one‐dimensional example, which shows that in the softening regime the proposed multiscale scheme behaves different from a bulk homogenization scheme. These results are also observed in a numerical simulation for a micro model with a periodic microstructure. Numerical simulations further demonstrate the applicability of the method. Copyright © 2010 John Wiley & Sons, Ltd.
The role of herbivores in Great Plains conservation: comparative ecology of bison and cattle

The Great Plains of North America evolved with significant influence from bison (Bison bison), but is presently dominated by cattle (Bos taurus). While there are a variety of opinions concerning differences between these two species, there is a lack of scientific comparisons, including those that incorporate important ecological variation. We developed a framework to study and compare the grazing behavior and effects of bison and cattle within grassland ecosystems. Environmental (e.g., resource distribution, disturbance) and animal (e.g., number, social organization) factors play a critical role in determining grazing effects and should be incorporated into discussions that compare the effects of bison and cattle. Using this framework we specifically compare the grazing behavior of both species in tallgrass prairie and discuss the implications of these differences in the context of conservation. We collared bison and cattle with global positioning systems and used resource selection functions to estimate the importance of various environmental factors on site selection. Both species preferred recently burned areas and avoided steeper slopes. Cattle selected areas that were closer to water, while bison were not limited by distance to water; cattle also preferred areas with woody vegetation, while bison avoided them. Incorporating broad scale environmental complexity allows for an effective comparison of ecological differences between bison and cattle. While there are similarities and differences in these species, a comprehensive analysis of all conditions and scenarios is not possible. It is clear, however, that the greatest differences between these species will likely be evident from broad scale studies across complex landscapes. In addition to species, conservation and land managers need to consider other environmental factors that are critical to grazing effects and overall conservation.
Differential Display Analysis of 2,3,7,8-Tetrachlorodibenzo-p-dioxin Identified Induction of Ras-related Nuclear Protein Binding Protein2 (RanBP2) Gene

TCDD (2,3,7,8-tetrachlorodibenzo- p -dioxin) and related halogenated aromatic hydrocarbons elicit a diverse spectrum of biochemical and toxic responses in laboratory animals and mammalian cells in culture. Toxicity and carcinogenicity of TCDD is well established but the molecular mechanism is still poorly understood. Here, we found the noble responsive genes to TCDD using the differential display analysis. Treatment of HepG2 cells with TCDD showed a significantly different mRNA expression pattern from the untreated cells in differential display analysis. The differentially displayed bands were isolated and used as probes in dot blot and Northern blot analyses. Of thirty-five isolated differentially displayed bands, only two bands were confirmed as positive in dot blot and Northern blot analyses. The nucleotides sequences of these clones were analyzed and the search of Genebank database revealed that one clone is highly homologous with RanBP2 (Ras-related nuclear protein binding protein2; 92%) and the other is an unknown gene. RanBP2 is a nucleoporin with SUMO E3 ligase activity that functions in both nucleocytoplasmic transport and mitosis and its role as a novel tumor suppressor has been recently proposed. Thus, these results may suggest the clue elucidating the toxic mechanism of TCDD through RanBP2.
COMPRESSED SENSINGWITH SEQUENTIAL OBSERVATIONS

Compressed sensing allows perfect recovery of sparse signals (or signals sparse in some basis) using only a small number of measurements. The results in the literature have focused on the asymptotics of how many samples are required and the probability of making an error for a fixed batch of samples. We investigate an alternative scenario where observations are available in sequence and can be stopped as soon as there is reasonable certainty of correct reconstruction. This approach does not require knowing how sparse is the signal, and allows reconstruction using the smallest number of samples. Central to our sequential approach is the stopping rule. For the random Gaussian ensemble we show that a simple stopping rule gives the absolute minimum number of observations required for exact recovery, with probability one. However, for other ensembles like Bernoulli or Fourier, this is no longer true, and the rule is modified to trade off delay in stopping and probability of error. We also consider near-sparse signals and describe how to estimate the reconstruction error from the sequence of solutions. This enables stopping once the error falls below a desired tolerance. Our sequential approach to compressed sensing involves a sequence of linear programs, and we outline how such a sequence can be solved efficiently.
Protrusion Guided 3 D Mesh Segmentation

Mesh segmentation, as a crucial step in model analysis and understanding, is vital to the success of the applications, e.g., the 3D reverse engineering and modeling by example. A number of recent works suggested segmenting 3D meshes on the basis of the cognitive psychology concept of “part salience”, which comprises three dominant factors: the protrusion degree , boundary strength, and relative size of the parts of the inspected object. In previous works, the estimation of salient feature such as protrusion degree is computation intensive. In this paper, we proposed a simpler measure of the protrusion degree based on the definition of 2D shape protrusion. With our new approach, the significant features can be successfully identified and extracted.
Assessment of Technical Efficiency and its Determinants in Beef Cattle Production in Kenya

The stochastic metafrontier method is applied to estimate technical efficiency levels in beef cattle production in Kenya. Subsequently, a Tobit model is used to assess factors that might influence efficiency. Results show that the average efficiency level is 0.69, suggesting that there is considerable scope to improve beef production in Kenya. Considering the importance of the livestock enterprise to rural livelihoods and its potential role in poverty reduction, there is need for appropriate development strategies for enhanced efficiency. In particular, livestock development policies should focus on provision of technology-related services. For instance, promoting use of controlled cattle crossbreeding methods would enhance productivity gains. Effective institutional support is also necessary in order to improve efficiency, including improved access to market contracts, better farm management skills and off-farm income opportunities.
Swarm optimization of stiffeners locations in 2-D structures

The paper is devoted to an application of the swarm methods and the finite element method to optimization of the stiffeners location in the 2-D structures (plane stress, bending plates and shells). The structures are optimized for the stress and displacement criteria. The numerical examples demonstrate that the method based on swarm computation is an effective technique for solving computer aided optimal design.
Allometric models for estimating the phytomass of a secondary Atlantic Forest area of southeastern Brazil

The purpose of this study was to develop and validate equations to estimate the aboveground phytomass of a 30 years old plot of Atlantic Forest. In two plots of 100 m2, a total of 82 trees were cut down at ground level. For each tree, height and diameter were measured. Leaves and woody material were separated in order to determine their fresh weights in field conditions. Samples of each fraction were oven dried at 80 °C to constant weight to determine their dry weight. Tree data were divided into two random samples. One sample was used for the development of the regression equations, and the other for validation. The models were developed using single linear regression analysis, where the dependent variable was the dry mass, and the independent variables were height (h), diameter (d) and d2h. The validation was carried out using Pearson correlation coefficient, paired t-Student test and standard error of estimation. The best equations to estimate aboveground phytomass were: lnDW = -3.068+2.522lnd (r2 = 0.91; sy/x = 0.67) and lnDW = -3.676+0.951ln d2h (r2 = 0.94; sy/x = 0.56).
Poverty and Access to Infrastructure in Papua New Guinea

In this paper, our overall goal is to understand how effective access to infrastructure is in reducing poverty in PNG. To meet this goal, we examine poverty in PNG, and seek to show the relationship between poverty and access to infrastructure and then identify the determinants of poverty. In our analysis, we test whether or not access to infrastructure is a significant factor in a household's poverty status. Finally, we want to understand what policies will be effective in overcoming poverty in PNG. Our results show that poverty in PNG is primarily rural and is associated with those in communities with poor access to services, markets, and transportation. Our simulations illustrate that improving access to school leads to large declines in poverty. Increasing access to poverty for those that are currently most isolated would have a significant effect in decreasing the severity of poverty.
Mixing Words and Emotions : New Natural Methods for Artificial Language Tutors (人工知能学会全国大会(第26回)文化,科学技術と未来) -- (International Organized Session「Alan Turing Year Special Session on AI Research That Can Change The World」)

In this paper we present the idea of an English tutoring system aimed to bring a new standard in language teaching. The Co-Mix project concentrates on second language vocabulary acquisition that is central to language itself and of high importance to the typical language learner. We compare some existing methods of teaching vocabulary and present the usefulness of our sentential context-learning method based on the phenomenon of code mixing. Since such a method has not yet been fully explored, we would like to progress with the research in the fields of natural language processing and artificial tutor systems. We also perform a preliminary experiment to our hypothesis on sentences with certain emotional loads. We investigate the effect of emotion on the learner’s performance in studying and propose how this method can be applied in a casual conversation system with the purpose of teaching English as a second language.
Quality perception of PDO beef producers

Food quality from a consumer perspective includes sanitary aspects as well as nutrition, but also taste, aspect, integrity and the particularity of products. But quality at the consumer level can only be achieved if quality is respected throughout the whole chain. An analysis is undertaken using as a case study Portuguese producers of two types of PDO beef. Results, using multivariate data analysis, show that the main attributes for a quality beef at the producers` level are: feeding, finishing, specific quality, age at slaughter, breed and transport. Results also suggest that producers have distinct quality perceptions on PDO beef.
Impact of private sector credit on the real sector of Nigeria

The real sector is a strategic component of an economy because it produces and distributes tangible goods and services required to satisfy aggregate demand in the economy. For this reason, there is the need for adequate credit flow from the banking industry to the real sector, which in the Nigerian case, the credit flow has been grossly inadequate. This study is carried out to examine the impact of credit to private sector (CPS) on the real sector of Nigeria with a view to assess the significant contribution of CPS to real sector growth in Nigeria. The study used aggregate time series data from 1986 to 2010, which was drawn from central bank of Nigeria (CBN) statistical bulletin and CBN annual report and statement of accounts. The data was analysed using multiple regression and based on the coefficient of determination (R square), the study reveals a 96.1% variation between the CPS and real sector growth in Nigeria. The study cocludes that there is a statistically significant impact of credit to private sector on the real sector of Nigeria. This, suggest that the performance of the real sector is greatly influence by credit to private sector. The study recommends that the federal government of Nigeria through the central bank of Nigeria (CBN) should enhance the financing of the real sector as well as improve credit flow to the sector because of its strategic importance in creating and generating growth of the economy.
Nanosization of Drug Biomaterials and Its Solubility Enhancement by High Energy Ball Milling

To evaluate the solubility enhancement of plant derived drugs in the form of nanosized biomaterials. Nanosization obtained from biomaterial sample of marine macro alga Padina gymosphora , using high energy ball milling technique and structural characteristic studies of biomaterials were evaluated using FE-SEM microscope. Solubility enhancement study on both biomaterials were tested using deionized double distilled water. FE-SEM microscopic study showed the particle size differentiation in the ordinary crude biomaterial and nanosized biomaterial. Water solubility studies proved the quick soluble and polydispersibility behaviour of nanosized biomaterial. The solubility enhancement properties of nanosized biomaterials indicated that, when the grain or particle size is reduced, the solubility is enhanced.
High Frequency Longitudinal Damped Vibrations of a Cylindrical Ultrasonic Transducer

Ultrasonic piezoelectric transducers used in classical nondestructive testing are producing in general longitudinal vibrations in the MHz range. A simple mechanical model of these transducers would be very useful for wave propagation numerical simulations, avoiding the existing complicated models in which the real components of the transducer are modeled by finite elements. The classical model for longitudinal vibrations is not adequate because the generated longitudinal wave is not dispersive, the velocity being the same at any frequency. We have adopted the Rayleigh-Bishop model, which avoids these limitations, even if it is not converging to the first but to the second exact longitudinal mode in an elastic rod, as obtained from the complicated Pochhammer-Chree equations. Since real transducers have significant vibrations damping, we have introduced a damping term in the Rayleigh-Bishop model, increasing the imaginary part and keeping almost identical real part of the wavenumber. Common transducers produce amplitude modulated signals, completely attenuated after several periods. This can be modeled by two close frequencies, producing a “beat” phenomenon, superposed on the high damping. For this reason, we introduce a two-rod Rayleigh-Bishop model with damping. Agreement with measured normal velocity on the transducer free surface is encouraging for continuation of the research.
Antiamnesic activity of the nicotinic agonist DBO‐83 in mice

The effect of administration of DBO‐83 on memory processes was evaluated in the mouse passive avoidance test. DBO‐83 (1–5 mgkg–1 ip) prevented amnesia induced by scopolamine (1.5 mgkg–1 ip), mecamylamine (20 mgkg–1 ip) and dihydro‐β‐erythroidine (10 μg per mouse i.c.v.). In the same experimental conditions, DBO‐83 (10 mgkg–1 ip) also prevented baclofen (2 mgkg–1 ip), clonidine (0.125 mgkg–1 ip) and diphenhydramine (20 mgkg–1 ip) amnesia in mice. The antiamnesic effect of DBO‐83 was comparable to that exerted by nicotine (2 mgkg–1 ip), physostigmine (0.2 mgkg–1 ip), and the nootropic drug, piracetam (30 mgkg–1 ip). In the antiamnesic dose‐range, DBO‐83 did not impair mouse motor coordination and spontaneous motility, as revealed, respectively, by the Animex apparatus and rotarod test. These results demonstrated the ability of DBO‐83 to modulate memory functions and suggest that DBO‐83 could be useful in the treatment of cognitive deficits. Drug Dev. Res. 45:45–51, 1998. © 1998 Wiley‐Liss, Inc.
Acquiring the user’s opinion by using a generalized Context-aware Recommender System for real-world applications

Acquiring the user’s opinion on specific things undoubtedly changes according to the given context. A context-aware or Multidimensional Recommender System can adapt its behaviour according to the user’s personal or environmental context. The same user may express or use completely different decision-making ways for various contexts to express the opinion . So, correct anticipation of user need depends upon the amount to which the relevant discourse data is in incorporated within the user’s opinion type. Here, we propose a generalized Context-aware recommender system that is suitable for all applications where a contextual segment plays a major role to find user’s opinion in real-world applications.
Innovation and Entrepreneurship: The Necessary Conditions of Value Creation

The necessary conditions of value creation are considered from the vantage point of innovation and entrepreneurship. Both demand side (basic needs, customer perceived value, and customer satisfaction) and supply side (science, technology, and knowledge) considerations of value creation are examined. The relationships between value creation and basic needs, customer perceived value, and knowledge are further examined. Although a number of factors are identified that impact value, only four are seen as primary factors of value: price, benefit, satisfaction, and experience. The innovator and entrepreneur can create value, and quantify the uniqueness of their value offerings, through these four primary factors. The study concludes that, on the demand side, basic needs may be an indirect driver of value creation, and customer perceived value as concept may be useful in the context of value creation. At the same time, it is believed that the four factors – price, benefit, satisfaction, and experience – can significantly explain value creation. On the supply side, innovation as the driver of value creation, is not necessarily confined to science and technology – business knowledge and acumen is an important avenue. In addition to existing knowledge and experience, factors like orientation (interests, passion, drive) and involvement also explain opportunity recognition.