Miracle-dz/UniFAR-FTUs huggingface dataset:
Sintering of Nano-Particle Powders: Simulations and Experiments

Abstract The sintering and consolidation of nano-particle powders were investigated using both computer simulation and direct experimentation. Molecular dynamics was employed to investigate the sintering of Cu nano-particles. Both spherical and cylindrical particles were employed in these simulations. The work demonstrates that sintering of these systems can take place on a time scale of tens of picoseconds, owing to the high shear stresses that develop at small particle contacts. For two and three particle sintering, it was observed that mass transport occurs by plastic flow. It was also found that crystallographically misaligned particles rotate to form low energy boundaries. The influence of the initial packing configuration was also investigated. Full densification occurs during pressureless sintering at room temperature only if the nano-particle assembly is close-packed. The effect of both isostauc and uniaxial stress on densification of Cu was also studied. Grain boundary sliding and grain boundary .
Liver mortality attributable to chronic hepatitis C virus infection in Denmark and Scotland—Using spontaneous resolvers as the benchmark comparator

Liver mortality among individuals with chronic hepatitis C (CHC) infection is common, but the relative contribution of CHC per se versus adverse health behaviors is uncertain. We explored data on spontaneous resolvers of hepatitis C virus (HCV) as a benchmark group to uncover the independent contribution of CHC on liver mortality. Using national HCV diagnosis and mortality registers from Denmark and Scotland, we calculated the liver mortality rate (LMR) for persons diagnosed with CHC infection (LMRchronic) and spontaneously resolved infection (LMRresolved), according to subgroups defined by age, sex, and drug use. Through these mortality rates, we determined subgroup‐specific attributable fractions (AFs), defined as (LMRchronic ‐ LMRresolved)/LMRchronic, and then calculated the total attributable fraction (TAF) as a weighted average of these AFs. Thus, the TAF represents the overall fraction (where 0.00 = not attributable at all; and 1.00 = entirely attributable) of liver mortality attributable to CHC in the diagnosed population. Our cohort comprised 7,005 and 21,729 persons diagnosed with HCV antibodies in Denmark and Scotland, respectively. Mean follow‐up duration was 6.3‐6.9 years. The TAF increased stepwise with age. It was lowest for death occurring at <45 years of age (0.21 in Denmark; 0.26 in Scotland), higher for death occurring at 45‐59 years (0.69 in Denmark; 0.69 in Scotland), and highest for death at 60+years (0.92 in Denmark; 0.75 in Scotland). Overall, the TAF was 0.66 (95% confidence interval [CI]: 0.55‐0.78) in Denmark and 0.55 (95% CI: 0.44‐0.66) in Scotland. Conclusions: In Denmark and Scotland, the majority of liver death in the CHC‐diagnosed population can be attributed to CHC—nevertheless, an appreciable fraction cannot, cautioning that liver mortality in this population is a compound problem that can be reduced, but not solved, through antiviral therapy alone. (Hepatology 2016;63:1506‐1516)
A study of effective features for detecting long-surviving Twitter spam accounts

As social networking websites get popular in recent years, the spam accounts on them also increase rapidly. A number of features to detect spam accounts have been proposed in prior studies. In this work, we evaluate the common features to see how effective they are to detect Twitter spam accounts or not. We used the Twitter APIs to collect 26,758 public accounts with 508,403 tweets intermittently over the period from September 2011 to March 2012. Although Twitter has its own method to detect and suspend spam accounts, many long-surviving spam accounts are still on it. We selected 816 out of the long-surviving accounts to persistently observe their activities and recorded their lifespans. We find that some features are not so effective for the detection, and thus select two features, the URL rate and the interaction rate, to be the detection features in this work. With classification by the J4.8 algorithm, the precision of the detection is estimated to be between 0.829 and 0.885, and the recall is between 0.987 and 0.999. We also present several additional techniques to further improve the detection accuracy.
How Does Number of Risk Factors Affect Prognosis in Young Patients With Ischemic Stroke?

Background and Purpose— We aimed to explore clinical features of young patients with ischemic stroke with no traditional vascular risk factors and to assess the impact of risk factor counts on outcomes. Methods— We included 990 patients aged 15 to 49 years with first-ever ischemic stroke followed for a mean of 9.0±3.8 years (survivors). Risk factors were categorized as well-documented and less well-documented. Outcome measures were unfavorable functional outcome (3-month modified Rankin Scale 2–6); recurrent ischemic stroke; myocardial infarction or other arterial noncerebrovascular event; and death from any cause. Results— Compared with those with at least 1 well-documented risk factor, the 127 (12.8%) patients without risk factors were younger (median age, 37 versus 44 years; P<0.001), likely to be females (54.3% versus 34.9%; P<0.001), and they had more frequently a low-risk source of cardioembolism (21.3% versus 8.1%; P<0.001), internal carotid artery dissection (12.6% versus 6.4%; P=0.011), or vertebral artery dissection (17.3% versus 7.2%; P<0.001). The groups had similar 3-month functional outcomes. Patients without well-documented risk factors had less frequently recurrent ischemic strokes (4.7% versus 13.6%; log rank P=0.014), noncerebrovascular arterial events (0% versus 6.1%; P=0.008), and lower long-term mortality (3.4% versus 14.3%; P=0.003) than did those with at least 1 risk factor. Adjusted for demographics and stroke etiology, the number of well-documented risk factors was associated with higher risk for noncerebrovascular events. Increasing count of less well-documented risk factors was, in turn, independently associated with higher long-term mortality. Conclusions— In young adults with first-ever ischemic stroke, risk factor counts added independent prognostic information regarding noncerebrovascular events and mortality.
Biologically Plausible Error-Driven Learning Using Local Activation Differences: The Generalized Recirculation Algorithm

The error backpropagation learning algorithm (BP) is generally considered biologically implausible because it does not use locally available, activation-based variables. A version of BP that can be computed locally using bidirectional activation recirculation (Hinton and McClelland 1988) instead of backpropagated error derivatives is more biologically plausible. This paper presents a generalized version of the recirculation algorithm (GeneRec), which overcomes several limitations of the earlier algorithm by using a generic recurrent network with sigmoidal units that can learn arbitrary input/output mappings. However, the contrastive Hebbian learning algorithm (CHL, also known as DBM or mean field learning) also uses local variables to perform error-driven learning in a sigmoidal recurrent network. CHL was derived in a stochastic framework (the Boltzmann machine), but has been extended to the deterministic case in various ways, all of which rely on problematic approximations and assumptions, leading some to conclude that it is fundamentally flawed. This paper shows that CHL can be derived instead from within the BP framework via the GeneRec algorithm. CHL is a symmetry-preserving version of GeneRec that uses a simple approximation to the midpoint or second-order accurate Runge-Kutta method of numerical integration, which explains the generally faster learning speed of CHL compared to BI. Thus, all known fully general error-driven learning algorithms that use local activation-based variables in deterministic networks can be considered variations of the GeneRec algorithm (and indirectly, of the backpropagation algorithm). GeneRec therefore provides a promising framework for thinking about how the brain might perform error-driven learning. To further this goal, an explicit biological mechanism is proposed that would be capable of implementing GeneRec-style learning. This mechanism is consistent with available evidence regarding synaptic modification in neurons in the neocortex and hippocampus, and makes further predictions.
Agent-Based Automated Negotiation System for Handling Vague Data Using Artificial Neural Network with Adaptive Back Propagation Algorithm

An auction market is a market in which buyers enter competitive bids and sellers enter competitive offers at the same time. Many negotiation systems have been proposed that rely on adequate and precise information provided by the negotiation parties for making their decisions. This paper provides mechanisms for addressing inadequate or missing information in a negotiation environment between a seller and many buyers which depends on multiple issues to make a decision. The system employs artificial neural network with adaptive momentum back propagation mechanism to determine whether a buyer should be selected among possible bid winners. The system then uses simple decision controls to determine the overall bid winner. The system was implemented using Java
Silorane low shrinkage composite: Evaluation of selective features

Restorative dentistry has undergone an important paradigm shift during the last two decades. Due to increased emphasis on preserving healthy tooth tissue the early concept of amalgam and cast restorations based on macro-mechanical retention coupled with inevitable tissue lost was replaced by the philosophy of minimally invasive dentistry. The introduction of predictable adhesive technologies has made this concept achievable. An adhesive tooth restorative technique enables diseased or lost tooth tissue be replaced by adhering the restorative material directly to the remaining sound tooth tissue. Due to their improved esthetic qualities, strength and wear resistance, resin composites are nowadays the restorative materials of first choice for replacement of lost natural tissues. It is generally accepted, that polymerization shrinkage of resin composite is a still unsolved problem in clinical dentistry. Therefore, the main objective of this project was to evaluate selective properties of a new low shrinking composite and to compare them with commonly used ones. This thesis mainly focuses on the influence of the low polymerization shrinkage and shrinkage stress formation on the marginal adaptation. The other factors such as different adhesive application protocols, different adhesive system combinations and dentinal fluid simulation in relation to the marginal adaptation are studied as well. Furthermore, the staining susceptibility of a Silorane resin composite is evaluated.
Linear and Weakly Nonlinear Stability Analyses of Cooperative Car-Following Models

Stability analyses have been widely used to better understand the mechanism of traffic jam formation. In this paper, we consider the impact of cooperative systems (a.k.a. connected vehicles) on traffic dynamics and, more precisely, on flow stability. Cooperative systems are emerging technologies enabling communication between vehicles and/or with the infrastructure. In a distributed communication framework, equipped vehicles are able to send and receive information to/from other equipped vehicles. Here, the effects of cooperative traffic are modeled through a general bilateral multianticipative car-following law that improves cooperative drivers' perception of their surrounding traffic conditions within a given communication range. Linear stability analyses are performed for a broad class of car-following models. They point out different stability conditions in both multianticipative and nonmultianticipative situations. To better understand what happens in unstable conditions, information on the shock wave structure is studied in the weakly nonlinear regime by the mean of the reductive perturbation method. The shock wave equation is obtained for generic car-following models by deriving the Korteweg de Vries equations. We then derive traffic-state-dependent conditions for the sign of the solitary wave (soliton) amplitude. This analytical result is verified through simulations. Simulation results confirm the validity of the speed estimate. The variation of the soliton amplitude as a function of the communication range is provided. The performed linear and weakly nonlinear analyses help justify the potential benefits of vehicle-integrated communication systems and provide new insights supporting the future implementation of cooperative systems.
Mechanism of the generation of black hole entropy in Sakharov’s induced gravity

The mechanism of the generation of Bekenstein-Hawking entropy S{sup BH} of a black hole in the Sakharov`s induced gravity is proposed. It is suggested that the {open_quotes}physical{close_quotes} degrees of freedom, which explain the entropy S{sup BH}, form only a finite subset of the standard Rindler-like modes defined outside the black hole horizon. The entropy S{sub R} of the Rindler modes, or entanglement entropy, is always ultraviolet divergent, while the entropy of the physical modes is finite and coincides in the induced gravity with S{sup BH}. The two entropies S{sup BH} and S{sub R} differ by a surface integral Q interpreted as a Noether charge of nonminimally coupled scalar constituents of the model. We demonstrate that energy E and Hamiltonian H of the fields localized in a part of space-time, restricted by the Killing horizon {Sigma}, differ by the quantity T{sub H}Q, where T{sub H} is the temperature of a black hole. The first law of black hole thermodynamics enables one to relate the probability distribution of fluctuations of the black hole mass, caused by the quantum fluctuations of the fields, to the probability distribution of physical modes over energy E. The latter turns out to be different from the distributionmore » of the Rindler modes. We show that the probability distribution of the physical degrees of freedom has a sharp peak at E=0 with the width proportional to the Planck mass. The logarithm of number of physical states at the peak coincides exactly with the black hole entropy S{sup BH}. This enables us to argue that the energy distribution of the physical modes and distribution of the black hole mass are equivalent in induced gravity. Finally it is shown that the Noether charge Q is related to the entropy of the low-frequency modes propagating in the vicinity of the bifurcation surface {Sigma} of the horizon. (Abstract Truncated)« less
A discrete-time approach to the modeling of carrier-sense multiple-access on the bus topology

An exact analysis of the carrier-sense multiple-access (CSMA) protocol on the bus topology is presented. All stations are synchronized to twice the distance between the uniformly distributed stations. The packet transmission time is an integer multiple of this synchronization step, and is at least equal to twice the end-to-end propagation delay. The makes the operation semisynchronous, rather than synchronous or asynchronous. The model is formulated as a time-homogeneous embedded Markovian chain and is solved under the steady-state condition. Both heterogeneous and homogeneous systems are considered. The system throughput is evaluated as well as the individual station throughput. The theory that the throughput achievable on the bus topology is greater than that achieved on a synchronous system is confirmed. It is also shown that the individual station throughput depends on the station location on the bus, and that stations near the center of the bus achieve higher throughput values. <<ETX>>
Role of Managerial Incentives and Discretion in Hedge Fund Performance

Using a comprehensive hedge fund database, we examine the role of managerial incentives and discretion in hedge fund performance. Hedge funds with greater managerial incentives, proxied by the delta of the option-like incentive fee contracts, higher levels of managerial ownership, and the inclusion of high-water mark provisions in the incentive contracts, are associated with superior performance. The incentive fee percentage rate by itself does not explain performance. We also find that funds with a higher degree of managerial discretion, proxied by longer lockup, notice, and redemption periods, deliver superior performance. These results are robust to using alternative performance measures and controlling for different data-related biases.
School performance in adolescents:: An educational neuropsychology perspective

154 Students in secondary school show large individual differences in school performance, even when they follow exactly the same classes. What could cause these differences? The present thesis investigated whether three factors, namely sex differences, breakfast consumption, and sleep, are determinants of individual differences in adolescents' school performance. It also examined neuropsychological mechanisms that might explain the influence of these determinants on school performance. See Chapter 1 for an introduction. The study in Chapter 2 investigated whether sex differences in vocabulary could explain girls' better performance on a language subject (Dutch). This question was investigated in two samples. In the first sample, 123 adolescents aged 14-–20 years completed a vocabulary test with an open-ended answer format. In the second sample, 556 adolescents aged 12–18 years completed a multiple-choice version of this test. In both samples, boys outperformed girls in knowledge of abstract nouns, yet vocabulary predicted report marks for language only in girls. It thus appears that vocabulary is not the mechanism underlying sex differences in language performance at school. The results of the first study emphasized the importance of examining mechanisms underlying sex differences in vocabulary more closely. In Chapter 3, we found that sex differences in vocabulary disappeared when words were presented in the context of a sentence. This was the result of a within-subjects experiment in 87 adolescents aged 13–15 years. They completed a 20-item multiple-choice vocabulary test with abstract nouns, of which half were presented in a sentence and half without a sentence. When words were presented without a sentence, boys outperformed girls. When words were presented in a sentence, girls' performance improved to boys' level, whereas no improvements for boys were found. The study in Chapter 4 investigated another mechanism underlying sex differences in school performance. Here, the relation between executive functions and school performance was examined. In a sample of 173 healthy adolescents in preuniversity education, aged 12–18 years, two objective tests of executive functions (Sorting Test and Tower Test from the Delis-Kaplan Executive Function System, D-KEFS) did not relate to report marks. A self-report measure of executive functions (Behavior Rating Inventory of Executive Function – Self-Report Version, BRIEF-SR) did relate to report marks, but could not predict report marks after controlling for grade, sex, and level of parental education. Moreover, these results did not differ for boys and girls. Thus, in healthy, high-performing adolescents these executive function tests were no better predictors of …
Isolates with Low-Level Vancomycin Resistance Associated with Persistent Methicillin-Resistant Staphylococcus aureus Bacteremia

ABSTRACT Low-level vancomycin-resistant Staphylococcus aureus (vancomycin-intermediate S. aureus [VISA] and heterogenous VISA [hVISA]) is increasingly reported and leads to glycopeptide treatment failure. Various phenotypic features have been reported for these isolates, but the genetic changes leading to hVISA and VISA have yet to be clearly determined. We assessed phenotypic, antibiotic resistance, and genomic changes by using genomic DNA microarray comparison and sequencing of selected loci in five pairs of clinical hVISA/VISA strains and the initial methicillin-resistant Staphylococcus aureus (MRSA) isolates obtained prior to vancomycin therapy. The isolates were from adult patients in Australia and New Zealand who had persistent MRSA bacteremia (>7 days) while receiving vancomycin therapy. In all cases, the initial isolates were found to be fully vancomycin-susceptible Staphylococcus aureus (VSSA). The hVISA/VISA phenotype was associated with increased cell wall thickness, reduced autolytic activity in four of five hVISA/VISA strains, and a striking reduction in biofilm formation compared to the parent strains in all pairs. All five pairs appeared to be isogenic, and genomic DNA microarray comparison suggested that major genetic changes are not required for the development of the resistant phenotype in these strains. No sequence differences were found in the agr locus or the tcaRA genes for any pair, but a marked reduction in RNAIII expression was found in four pairs. In summary, hVISA/VISA arises from fully VSSA during persistent infection that fails to respond to glycopeptide therapy and is associated with significant phenotypic changes, including a marked reduction in biofilm-forming ability. These clinically derived pairs of isolates will be a useful resource to elucidate the genetic mechanism of resistance in hVISA/VISA strains.
Current Efficiency in Accelerated Corrosion Testing of Concrete

The suitability of accelerated corrosion testing using an impressed current, especially the accuracy of Faraday's law to estimate the mass loss, was assessed in this paper. A variety of tests were performed in concrete and solution with different chloride concentrations and impressed current to assess the accuracy of using Faraday's law to estimate the mass loss of corroded steel. The results indicate that Faraday's law does not predict the mass loss accurately for all conditions, and the percentage error increases with decreasing chloride concentration in the system. It is hypothesized that Faraday's law cannot be used to estimate the mass loss because competing reactions take place at the anode, especially at low chloride concentrations and high current. Under unfavorable conditions, only a part of the impressed current oxidizes the anode to create corrosion products while the remaining current is consumed in competing reactions.
Smoothing Spline Semiparametric Nonlinear Regression Models

We consider the problem of modeling the mean function in regression. Often there is enough knowledge to model some components of the mean function parametrically. But for other vague and/or nuisance components, it is often desirable to leave them unspecified and to be modeled nonparametrically. In this article, we propose a general class of smoothing spline semiparametric nonlinear regression models (SNRMs) which assumes that the mean function depends on parameters and nonparametric functions through a known nonlinear functional. SNRMs are natural extensions of both parametric and nonparametric regression models. They include many popular nonparametric and semiparametric models such as the partial spline, varying coefficients, projection pursuit, single index, multiple index, and shape-invariant models as special cases. Building on reproducing kernel Hilbert spaces (RKHS), the SNRMs allow us to deal with many different situations in a unified fashion. We develop a unified estimation procedure based on minimizing penalized likelihood using Gauss–Newton and backfitting algorithms. Smoothing parameters are estimated using the generalized cross-validation (GCV) and generalized maximum likelihood (GML) methods. We derive Bayesian confidence intervals for the unknown functions. A generic and user-friendly R function is developed to implement our estimation and inference procedures. We illustrate our methods with analyses of two real datasets and evaluate finite-sample performance by simulations. Datasets, computer code and derivation of posterior covariances are available in the online supplements.