Miracle-dz/UniFAR-FTUs huggingface dataset:
Disassortative mixing in online social networks

The conventional wisdom is that social networks exhibit an assortative mixing pattern, whereas biological and technological networks show a disassortative mixing pattern. However, the recent research on the online social networks modifies the widespread belief, and many online social networks show a disassortative or neutral mixing feature. Especially, we found that an online social network, Wealink, underwent a transition from degree assortativity characteristic of real social networks to degree disassortativity characteristic of many online social networks, and the transition can be reasonably elucidated by a simple network model that we propose. The relations among network assortativity, clustering, and modularity are also discussed in the paper.
Capabilities, processes, and performance of knowledge management: A structural approach

The purpose of this study is to examine structural relationships among the capabilities, processes, and performance of knowledge management, and suggest strategic directions for the successful implementation of knowledge management. To serve this purpose, the authors conducted an extensive survey of 68 knowledge management‐adopting Korean firms in diverse industries and collected 215 questionnaires. Analyzing hypothesized structural relationships with the data collected, they found that there exists statistically significant relationships among knowledge management capabilities, processes, and performance. The empirical results of this study also support the well‐known strategic hypothesis of the balanced scorecard (BSC). © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 21–41, 2007.
Agricultural Trade Liberalization in Mexico : Impact on Border Prices and Farmers ’ Income

This paper examines the impact of trade liberalization in agricultural products between Mexico and the U.S. due to NAFTA on the distribution of Mexican farm incomes during the 1990s. By relating NAFTA tariff cuts to border prices of Mexican exports and imports, we are able to examine both benefits to Mexican farmers resulting from higher prices of export goods, as well as losses incurred from greater import competition. Using farm households as the unit of observation allows us to examine the distributive impact of these changes in border prices at a high level of disaggregation, and identify the channels through which trade liberalization impacts relative incomes of farms of differing size. We find that NAFTA-induced tariff reductions decreased the border price of Mexican import goods, most notably corn, and increased the border prices of Mexican export goods such as fruits and vegetables. The rise in fruit and vegetable prices benefited small farmers more than large farmers, while the drop in corn prices hurt large farmers more. These results are consistent with observed cropping patterns: large farms rely more on corn while small farms rely more on fruits and vegetables. We also assess separately the impact on northern, central and southern parts of Mexico. The results are stronger in the central region, consistent with the fact that only this region is characterized both by good land quality and low transportation costs to the border. These findings indicate that trade liberalization increased the level of earning of poor farmers relative to those of large farmers in the central region of Mexico. ∗This paper is a revised version of a chapter of my doctoral dissertation at Boston University. First and foremost I would like to thank Dilip Mookherjee for his continuous guidance and support. I also gratefully acknowledge comments from Iván Fernández-Val, Kevin Lang, Nina Pavcnik, Eric Verhoogen and seminar participants at Boston University. Special thanks to Nava Ashraf and Margaret McMillan for sharing their data, and to Juan Carlos Torres of INEGI for tireless data assistance. †Department of Economics, Weatherhead School of Management, 11119 Bellflower Road, Room 273, Case Western Reserve University, Cleveland, Ohio 44106-7235. Correspondence: silvia.prina@case.edu
The Relevance of Learning Processes for IT Implementation

The starting point of this paper is the belief that it is neither the quality of the technology, nor that of the individual users, but the interactions among people in groups of users concerning a new system that determines the success or failure of IT implementation. Aiming at conceptualization of the role of group learning in IT implementation, we first develop a theoretical framework based on the experiential learning cycle that includes five processes: collective acting, group reflecting, knowledge disseminating, sharing understanding, and mutual adjustment. Second, we illustrate the roles of learning processes in three case studies. Analysis of the interviews with 98 users of information technologies has revealed a unique function of group learning in the IT implementation. It is shown that group learning emerges immediately after a new IT is introduced to the targeted users; it may take different directions (for or against adoption of the technology); it itself can develop during the IT implementation and either progress or take a turn for the worse. The paper elaborates on three organizational conditions important for directing the constructive group learning: managerial support issues, structural and non-structural group characteristics, and technological features that turn group learning in a positive direction.
Beyond valence in the perception of likelihood: the role of emotion specificity.

Positive and negative moods have been shown to increase likelihood estimates of future events matching these states in valence (e.g., E. J. Johnson & A. Tversky, 1983). In the present article, 4 studies provide evidence that this congruency bias (a) is not limited to valence but functions in an emotion-specific manner, (b) derives from the informational value of emotions, and (c) is not the inevitable outcome of likelihood assessment under heightened emotion. Specifically, Study 1 demonstrates that sadness and anger, 2 distinct, negative emotions, differentially bias likelihood estimates of sad and angering events. Studies 2 and 3 replicate this finding in addition to supporting an emotion-as-information (cf. N. Schwarz & G. L. Clore, 1983), as opposed to a memory-based, mediating process for the bias. Finally, Study 4 shows that when the source of the emotion is salient, a reversal of the bias can occur given greater cognitive effort aimed at accuracy.
Estimation of delay times from a delayed optical feedback laser experiment

We estimate delay times from high-dimensional chaotic time series experimentally obtained from a fast optical time-delayed feedback system. The experiment consists of a semiconductor laser, where the instabilities are induced by an external T-shaped cavity introducing two delay times into the laser. The delay times are determined by a filling factor analysis and found to give a better estimate than those obtained by autocorrelation functions. Finally, the possibility of this method for the reconstruction of the system's differential equations is discussed.
Using Tracer Observations to Reduce the Uncertainty of Ocean Diapycnal Mixing and Climate 1 -carbon Cycle Projections 2 3 4

24 25 What is the uncertainty of climate-carbon cycle projections in response to anthropogenic 26 greenhouse gas emissions and how can we reduce this uncertainty? We address this question by 27 quantifying the ability of available ocean tracer observations to constrain the values of diapycnal 28 diffusivity in the pelagic ocean (K v), a key uncertain parameter representing sub-gridscale 29 diapycnal (vertical) mixing in physical circulation models. We show that model versions with 30 weak mixing lead to higher projections of atmospheric CO 2 and larger global warming than 31 models with vigorous mixing. Slower heat uptake as well as slower carbon uptake by the oceans 32 contribute about equally to the accelerated warming in the low mixing models. A Bayesian data-33 model fusion method is developed to quantify the likelihood of different structural and 34 parametric model choices given an array of observed 20th century ocean tracer distributions. 35 These spatially resolved observations provide strong limits on the upper value of K v , whereas 36 global metrics used in previous studies, such as the historical evolution of global average surface 37 air temperature, global ocean heat uptake, or atmospheric CO 2 concentration, provide only poor 38 constraints. We compare different methods to quantify the probability of a particular K v value 39 given the observational constraints. One-dimensional (horizontally averaged) data result in 40 sharper probability density functions compared with the full 3D fields. This unexpected result 41 opens an avenue to objectively determine the optimal degree of aggregation at which model 42 predictions have skill, and at which observations are most helpful in constraining model 43 parameters. Our best estimate for K v in the pelagic pycnocline is around 0.05-0.2 cm 2 /s, in 44 agreement with earlier independent estimates based on tracer dispersion experiments and 45 turbulence microstructure measurements. 46 47 48 3
COSBench: cloud object storage benchmark

With object storage systems being increasingly recognized as a preferred way to expose one's storage infrastructure to the web, the past few years have witnessed an explosion in the acceptance of these systems. Unfortunately, the proliferation of available solutions and the complexity of each individual one, coupled with a lack of dedicated workload, makes it very challenging for one to evaluate and tune the performance of different systems. To help address this problem, we present the Cloud Object Storage Benchmark (COSBench). It is a benchmark tool that we have developed at Intel with the goal of facilitating both performance comparison and system optimization of these systems. In this paper, we describe the design and implementation of this tool, focusing on its extensibility and scalability. In addition, we discuss how people can use this tool to perform system characterization and how the latter can facilitate system comparison and optimization. To demonstrate the value of our tool, we report the results of our experiments conducted on two Swift setups we built in our lab. We also share some of our experiences in turning our setups to achieve higher performance.
A History of EI/ECSE in the United States: A Personal Perspective

This article offers a view of the evolution of Early Intervention/Early Childhood Special Education (EI/ECSE) in the United States. This view of the field’s growth and change over time reflects the personal memories, experiences, and perspectives of Diane Bricker, who reviews the evolutionary changes in EI/ECSE based on her experiences with a range of theorists, scientists, and clinicians who affected the EI/ECSE profession both directly and indirectly. The challenge of succinctly summarizing the history of EI/ECSE required Bricker to make many difficult choices and prohibited recognizing many important contributors and events over the years. The following narrative of her presentation provides a powerful backdrop for the future of the field.
Impact of Different Fecal Processing Methods on Assessments of Bacterial Diversity in the Human Intestine

The intestinal microbiota are integral to understanding the relationships between nutrition and health. Therefore, fecal sampling and processing protocols for metagenomic surveys should be sufficiently robust, accurate, and reliable to identify the microorganisms present. We investigated the use of different fecal preparation methods on the bacterial community structures identified in human stools. Complete stools were collected from six healthy individuals and processed according to the following methods: (i) randomly sampled fresh stool, (ii) fresh stool homogenized in a blender for 2 min, (iii) randomly sampled frozen stool, and (iv) frozen stool homogenized in a blender for 2 min, or (v) homogenized in a pneumatic mixer for either 10, 20, or 30 min. High-throughput DNA sequencing of the 16S rRNA V4 regions of bacterial community DNA extracted from the stools showed that the fecal microbiota remained distinct between individuals, independent of processing method. Moreover, the different stool preparation approaches did not alter intra-individual bacterial diversity. Distinctions were found at the level of individual taxa, however. Stools that were frozen and then homogenized tended to have higher proportions of Faecalibacterium, Streptococcus, and Bifidobacterium and decreased quantities of Oscillospira, Bacteroides, and Parabacteroides compared to stools that were collected in small quantities and not mixed prior to DNA extraction. These findings indicate that certain taxa are at particular risk for under or over sampling due to protocol differences. Importantly, homogenization by any method significantly reduced the intra-individual variation in bacteria detected per stool. Our results confirm the robustness of fecal homogenization for microbial analyses and underscore the value of collecting and mixing large stool sample quantities in human nutrition intervention studies.
Bias and Size Effects of Price-Comparison Search Engines: Theory and Experimental Evidence ?

We analyze the impact on consumer prices of the size and bias of price comparison search engines. In the context of a model related to Burdett and Judd (1983) and Varian (1980), we develop and test experimentally several theoretical predictions. The experimental results confirm the model’s predictions regarding the impact of the number of firms, and the type of bias of the search engine, but reject the model’s predictions regarding changes in the size of the index. The explanatory power of an econometric model for the price distributions is significantly improved when variables accounting for risk attitudes are introduced.
Fully Depleted Pinned Photodiode CMOS Image Sensor With Reverse Substrate Bias

A new pixel design using fully depleted pinned photodiode (PPD) in a 180-nm CMOS image sensor (CIS) process has been developed and the first experimental results from a test chip are presented. The sensor can be fully depleted by means of reverse bias applied to the substrate, and the principle of operation is applicable to very thick sensitive volumes. Additional n-type implants under the in-pixel p-wells have been added to the manufacturing process in order to eliminate the large parasitic substrate current that would otherwise be present in a normal device. The new design shows the same electro-optical performance as the PPD pixel it is based on, and can be fully depleted without significant leakage currents. This development has the potential to greatly increase the quantum efficiency of scientific PPD CIS at near-infrared and soft X-ray wavelengths.
PFC Neurons Reflect Categorical Decisions about Ambiguous Stimuli

We examined whether PFC neuron activity reflects categorical decisions in monkeys categorizing ambiguous stimuli. A morphing system was used to systematically vary stimulus shape and precisely define category boundaries. Ambiguous stimuli were centered on a category boundary, that is, they were a mix of 50% of two prototypes and therefore had no category information, so monkeys guessed at their category membership. We found that the monkeys' trial-by-trial decision about the category membership of an ambiguous image was reflected in PFC activity. Activity to the same ambiguous image differed significantly, depending on which category the monkey had assigned it to. This effect only occurred when that scheme was behaviorally relevant. These indicate that PFC activity reflects categorical decisions.
Binary nucleation in acid–water systems. II. Sulfuric acid–water and a comparison with methanesulfonic acid–water

This work presents a systematic investigation of binary nucleation rates for sulfuric acid and water and the effect of temperature on these rates at isothermal, subsaturated conditions. The results from nucleation rate measurements for the sulfuric acid (H2SO4)–water system are discussed and compared to those previously presented for methanesulfonic acid (MSA)–water [B. E. Wyslouzil, J. H. Seinfeld, R. C. Flagan, and K. Okuyama, J. Chem. Phys. (submitted)]. Experiments were conducted at relative humidities (Rh) ranging from 0.006<Rh<0.65, relative acidities (Ra) in the range of 0.04<Ra<0.46, and at three temperatures, T=20, 25, and 30 °C, in the continuous flow mixing-type apparatus described in Paper I. Particles were formed by binary nucleation and grew by condensation as the mixed stream flowed through an isothermal glass tube. Number concentrations observed at the exit of the nucleation and growth tube as a function of Rh and Ra are extremely sensitive to the binary nucleation rate, and from these data the nucleation rate was estimated as a function of saturation level and temperature. Particle size distributions were also measured using a specially constructed differential mobility analyzer. As anticipated, the H2SO4 particles formed by nucleation and growth are much smaller than those formed in the MSA–water experiments, but particle size distribution measurements confirm that most of the particles formed are being observed. The ratio of experimental to theoretical nucleation rates, Jexpt/Jtheor, was found to be a strong function of the predicted number of acid molecules in the critical nucleus for both the H2SO4–water and MSA–water systems.
Corporate Governance and Firm-Specific Stock Price Crashes

We investigate whether four dimensions of corporate governance mechanisms, namely ownership structure, accounting opacity, board structure and process and managerial incentives, relate to 1-year-ahead stock price crash risk. Employing principal component analysis on the 21 attributes that comprise these four categories, we find that corporate governance explains overall between 13.1% and 23.0% of a one standard deviation in future crash risk. Further analysis reveals that transient institutional ownership, CEO stock option incentives and the percentage of directors that hold equity in the firm increase a firm’s future stock price crash, whilst insiders’ ownership, conditional accounting conservatism, board size and the presence of a corporate governance policy have the ability to mitigate crashes. The relations between these governance attributes and future crash risk are more pronounced in environments that accentuate agency risk. Our findings support the notion that sound corporate governance systems curb opportunistic behavior of managers to hide and accumulate bad news from outsiders.
&bgr;-Adrenoreceptor Antagonists Attenuate Brain Injury After Transient Focal Ischemia in Rats

&bgr;-adrenoreceptor antagonists experimentally reduce cardiac and renal injury after ischemia and are also clinically useful for myocardial infarction and severe burns. In addition, &bgr;-adrenoreceptor antagonists provide neuroprotective effects after focal cerebral ischemia in experimental settings. We conducted the present study to compare the neuroprotective effects of several &bgr;-adrenoreceptor antagonists in rat transient focal cerebral ischemia. Halothane-anesthetized normothermic adult male Sprague-Dawley rats were subjected to 2 h of middle cerebral artery occlusion using the intraluminal suture technique confirmed by laser Doppler flowmetry. Rats received an IV infusion of saline 0.5 mL/h, propranolol 100 &mgr;g · kg−1 · min−1, carvedilol 4 &mgr;g · kg−1 · min−1, esmolol 200 &mgr;g · kg−1 · min−1, or landiolol 50 &mgr;g · kg−1 · min−1 (n = 6 in each group). Infusion was initiated 30 min before middle cerebral artery occlusion and continued for 24 h. Additional rats received esmolol 50 &mgr;g · kg−1 · min−1 or landiolol 10 &mgr;g · kg−1 · min−1 intrathecally (IT) via the cisterna magna (n = 5 in each group), according to the same experimental protocol. The neurological deficit score was evaluated at 22 h after reperfusion, and the brains were removed and stained with triphenyltetrazolium chloride for evaluation of infarct volume. Additional rats that received saline, esmolol, and landiolol IV (n = 6 in each group) were allowed to survive for 7 days followed by measurement of infarct size. Neurological deficit scores were smaller in rats treated with propranolol-IV, carvedilol-IV, esmolol-IV, landiolol-IV, esmolol-IT, and landiolol-IT compared with saline-treated rats (P < 0.05). Cortical and striatum infarct volumes were less in the rats receiving &bgr;-adrenoreceptor antagonists via either IV or IT than in saline-treated rats (P < 0.05). We conclude that &bgr;-adrenoreceptor antagonists improve neurological and histological outcomes after transient focal cerebral ischemia in rats independent of administration route.
Global mapping functions for the atmosphere delay at radio wavelengths

I have developed expressions for calculating the ratios (mapping functions) of the “line of sight” hydrostatic and wet atmospheric path delays to their corresponding zenith delays at radio wavelengths for elevation angles down to 3°. The coefficients of the continued fraction representation of the hydrostatic mapping function depend on the latitude and height above sea level of the observing site and on the day of the year; the dependence of the wet mapping function is only on the site latitude. By comparing with mapping functions calculated from radiosonde profiles for sites at latitudes between 43°S and 75°N, the hydrostatic mapping function is seen to be more accurate than, and of comparable precision to, mapping functions currently in use, which are parameterized in terms of local surface meteorology. When the new mapping functions are used in the analysis of geodetic very long baseline interferometry (VLBI) data, the estimated lengths of baselines up to 10,400 km long change by less than 5 mm as the minimum elevation of included data is reduced from 12° to 3°. The independence of the new mapping functions from surface meteorology, while having comparable accuracy and precision to those that require such input, makes them particularly valuable for those situations where surface meteorology data are not available.
Step length reductions in advanced age: the role of ankle and hip kinetics.

BACKGROUND Aging is associated with a reduction in gait velocity, which is due to a shortened step length. This study investigated the relationship between joint kinetics and step length. METHODS Three-dimensional gait kinematics and kinetics were measured during usual pace gait in 26 older subjects (average age 79) and in 32 young subjects (average age 26). Gait measures were obtained at maximal velocity in five older subjects. Lower extremity strength was measured in the older subjects on an isokinetic dynamometer. RESULTS Older persons had a 10% shorter step length during usual gait, when corrected for leg length (.65 +/- .07, .74 +/- .04/leg length, respectively, p < .001). Older persons had reduced ankle plantarflexion during late stance (13 +/- 5 degrees, 17 +/- 5 degrees, p = .02) and lower ankle plantarflexor power (2.9 +/- 0.9 W kg-1, 3.5 +/- 0.9 W kg-1, respectively, p = .007). Ankle strength was associated with plantarflexor power developed during late stance (r = .49, p < .001). When gait kinetics were corrected for step length, the older subjects developed 16% greater hip flexor power during late stance than younger subjects (estimate of effect: .15 W kg-1, p = .002). Older subjects were unable to increase ankle plantarflexor power at maximal pace, but increased hip flexor power 72% (1.1 +/- 0.3 W kg-1 to 1.9 +/- 1.0 W kg-1, p = .02). CONCLUSIONS Older subjects had lower ankle plantarflexor power during the late stance phase of gait and appeared to compensate for reductions in plantarflexor power by increasing hip flexor power. Appropriate training of ankle plantarflexor muscles may be important in maintaining step length in advanced age.