Miracle-dz/UniFAR-FTUs huggingface dataset:
Associative Memory in a Network of 'Biological' Neurons

The Hopfield network (Hopfield, 1982, 1984) provides a simple model of an associative memory in a neuronal structure. This model, however, is based on highly artificial assumptions, especially the use of formal-two state neurons (Hopfield, 1982) or graded-response neurons (Hopfield, 1984). What happens if we replace the formal neurons by 'real' biological neurons? We address this question in two steps. First, we show that a simple model of a neuron can capture all relevant features of neuron spiking, i.e., a wide range of spiking frequencies and a realistic distribution of interspike intervals. Second, we construct an associative memory by linking these neurons together. The analytical solution for a large and fully connected network shows that the Hopfield solution is valid only for neurons with a short refractory period. If the refractory period is longer than a critical duration γc, the solutions are qualitatively different. The associative character of the solutions, however, is preserved.
Cytotoxicity and Genotoxicity of Panel of Single- and Multiwalled Carbon Nanotubes: In Vitro Effects on Normal Syrian Hamster Embryo and Immortalized V79 Hamster Lung Cells

Carbon nanotubes (CNTs) belong to a specific class of nanomaterials with unique properties. Because of their anticipated use in a wide range of industrial applications, their toxicity is of increasing concern. In order to determine whether specific physicochemical characteristics of CNTs are responsible for their toxicological effects, we investigated the cytotoxic and genotoxic effects of eight CNTs representative of each of the commonly encountered classes: single- SW-, double- DW-, and multiwalled (MW) CNTs, purified and raw. In addition, because most previous studies of CNT toxicity were conducted on immortalized cell lines, we decided to compare results obtained from V79 cells, an established cell line, with results from SHE (Syrian hamster embryo) cells, an easy-to-handle normal cell model. After 24 hours of treatment, MWCNTs were generally found to be more cytotoxic than SW- or DWCNTs. MWCNTs also provoked more genotoxic effects. No correlation could be found between CNT genotoxicity and metal impurities, length, surface area, or induction of cellular oxidative stress, but genotoxicity was seen to increase with CNT width. The toxicity observed for some CNTs leads us to suggest that they might also act by interfering with the cell cycle, but no significant differences were observed between normal and immortalized cells.
What's the Story?: Exploring Parent–Teacher Communication through ePortfolios

ELECTRONIC PORTFOLIOS (ePORTFOLIOS) ARE a relatively new phenomenon in early childhood education (ECE) with minimal existing research available on their use and effectiveness as a learning and communication tool in ECE. This article reports on a study examining the influence of ePortfolios on parent–teacher communication in one early childhood (EC) service. Reported data has been drawn from online surveys, document analysis of ePortfolios, individual interviews and focus group interviews with parents and teachers. Thematic analysis identified two main themes: the benefits and drawbacks of communicating via the ePortfolio, and the types of communication that were evident.
A Block Algorithm for Matrix 1-Norm Estimation, with an Application to 1-Norm Pseudospectra

The matrix 1-norm estimation algorithm used in LAPACK and various other software libraries and packages has proved to be a valuable tool. However, it has the limitations that it offers the user no control over the accuracy and reliability of the estimate and that it is based on level 2 BLAS operations. A block generalization of the 1-norm power method underlying the estimator is derived here and developed into a practical algorithm applicable to both real and complex matrices. The algorithm works with n × t matrices, where t is a parameter. For t=1 the original algorithm is recovered, but with two improvements (one for real matrices and one for complex matrices). The accuracy and reliability of the estimates generally increase with t and the computational kernels are level 3 BLAS operations for t > 1. The last t-1 columns of the starting matrix are randomly chosen, giving the algorithm a statistical flavor. As a by-product of our investigations we identify a matrix for which the 1-norm power method takes the maximum number of iterations. As an application of the new estimator we show how it can be used to efficiently approximate 1-norm pseudospectra.
Behavioural and Experimental Public Administration: Emerging Contributions and New Directions

This article introduces the symposium on the emerging subfield of behavioural public administration. The nine articles of the symposium each combine a focus on behavioural theory with the use of experiments as the method for testing theoretical expectations. The contribution of this work to public administration theory is revealed in the expanding set of insights into core topic areas, and there are associated contributions to public administration as a design science informing policy and practice. We analyse the variety of experimental methods employed by investigators in the subfield and the current relative popularity of survey experiments. We note maturation of the subfield embodied in emerging programmes of multiple experiments on particular topic areas. In conclusion, we propose directions for future research in which behavioural public administration develops as complementary to more established approaches to theory and method.
A Comparative Analysis between Active and Passive Techniques for Underwater 3D Reconstruction of Close-Range Objects

In some application fields, such as underwater archaeology or marine biology, there is the need to collect three-dimensional, close-range data from objects that cannot be removed from their site. In particular, 3D imaging techniques are widely employed for close-range acquisitions in underwater environment. In this work we have compared in water two 3D imaging techniques based on active and passive approaches, respectively, and whole-field acquisition. The comparison is performed under poor visibility conditions, produced in the laboratory by suspending different quantities of clay in a water tank. For a fair comparison, a stereo configuration has been adopted for both the techniques, using the same setup, working distance, calibration, and objects. At the moment, the proposed setup is not suitable for real world applications, but it allowed us to conduct a preliminary analysis on the performances of the two techniques and to understand their capability to acquire 3D points in presence of turbidity. The performances have been evaluated in terms of accuracy and density of the acquired 3D points. Our results can be used as a reference for further comparisons in the analysis of other 3D techniques and algorithms.
Land tenurial systems and the adoption of Mucuna planted fallow in the derived savannas of West Africa

In 1987, an improved resource management system that incorporates velvet bean (Mucuna pruriens var. utilis) to address soil fertility and weed (Imperata cylindrica) infestation was introduced to the small-scale farmers in a densely populated area of the derived savannas in Benin Republic (West Africa). Six years later, an adoption study was conducted to assess factors driving the adoption process. Four types of land tenure systems based on mode of access to land were identified: divided inheritance, purchasing, gifts, and sharecropping/renting. The first three provide long-term security over land, and together, they represent about 76 percent of the survey fields. Results from three variants of a probit model indicated that security over land was among the factors that significantly affect the adoption of the technology, with a high marginal effect on the probability of adoption, while gender did not have a significant effect. The most important determinant for adoption is the number of times a field is weeded during a cropping season (a proxy for the amount of labor required to tend a crop for better yields). High weeding requirements favorably affect the adoption of velvet bean only if farmers have full security on the degraded (weedy) land. The predominance of land tenure systems that provide secure property rights, namely the traditional acquisition of land through inheritance or gift mode and the gradual development of a land market, facilitated a quick spread of the Mucuna planted fallows in the study region.
Bandwidth Allocation to Interactive Users in DBS-Based Hybrid Internet

Title of Thesis: BANDWIDTH ALLOCATION TO INTERACTIVE USERS IN DBS-BASED HYBRID INTERNET Degree candidate: Marian Stagarescu Degree and year: Master of Science, Department of Electrical Engineering, University of Maryland, College Park, 1998 Thesis directed by: Professor John S. Baras Department of Electrical Engineering We are motivated by the problem of bandwidth allocation to Internet users in DBS-based Hybrid Internet, where the Network Operations Center (NOC)scheduler controls the amount of service provided to each user, by using packet scheduling and buffer management. Such a system exploits the ability of satellites to offer high bandwidth connections to large geographical areas, and it delivers low-cost hybrid (satellite-terrestrial) high-speed services to interactive Internet users. In this system, it is important to reduce the delay that users experience. We analyze several bandwidth allocation policies at the Network Operations Center (NOC) of a DBS-based hybrid Internet network. We consider the problem of optimal scheduling of the services of interactive users in the DBS-based hybrid Internet configuration. We show that, for the interactive Internet users, the Most Delayed Queue First (MDQF) policy, which serves the queues starting with the most delayed queue, is providing the minimum delay, when compared with the Equal Bandwidth (EB) and Fair Share (FS) allocation policies. The MDQF policy is shown to be optimal with respect to a performance metric of packet loss due to queuing time constraints. The impact of the scheduling policies on the Hybrid Internet system’s performance, is analyzed in the context of the interplay between the NOC queuing system (and its bandwidth allocation policies) and the underlying transport protocol (TCP), and we show the effectiveness of the MDQF policy in the presence of TCP congestion control algorithm. We also present simulations in which the Internet server sources send selfsimilar (“fractal”) data traffic to the NOC-scheduler. The results confirm our calculations, that the MDQF policy is a better performing policy for minimizing the mean delay at high load factors, when comparing it to the EB and FS policies. Finally, we propose two solutions, a buffer allocation policy and a ”virtual delay” mechanism, which make the MDQF policy work in the presence of greedy sources. BANDWIDTH ALLOCATION TO INTERACTIVE USERS IN DBS-BASED HYBRID INTERNET by Marian Stagarescu Thesis submitted to the Faculty of the Graduate School of the University of Maryland, College Park in partial fulfillment of the requirements for the degree of Master of Science Advisory Committee: Professor John S. Baras, Chairman/Advisor Professor Prakash Narayan Assistant Research Scientist M. Scott Corson c © Copyright by Marian Stagarescu Department of Electrical Engineering, University of Maryland, College Park 1998
An Unsupervised Method for Canonicalization of Japanese Postpositions

We present an unsupervised method for canonicalizing joshi (postpositions) in Japanese. Some postpositions in Japanese do not specify semantic roles explicitly as case markers do, although those postpositions syntactically behave as the case markers. Such postpositions includes “wa,” which topicalizes noun phrases, and “mo,” which emphasizes noun phrases. For this paper, we replaced these postpositions in a sentence with case markers, without changing the meanings of the original sentence as little as possible. This leads to canonicalization or paraphrasing of verb phrases into canonical forms with desirable properties. Our method utilized case frames and semantic word classifications induced by the Expectation Maximization algorithm. The induction process was unsupervised in the sense that no semantic clues were given before the induction of the case frames and the word classifications.
Sensitivity in binding free energies due to protein reorganization

Tremendous recent improvements in computer hardware, coupled with advances in sampling techniques and force fields, are now allowing protein-ligand binding free energy calculations to be routinely used to aid pharmaceutical drug discovery projects. However, despite these recent innovations, there are still needs for further improvement in sampling algorithms to more adequately sample protein motion relevant to protein-ligand binding. Here, we report our work identifying and studying such clear and remaining needs in the apolar cavity of T4 Lysozyme L99A. In this study, we model recent experimental results that show the progressive opening of the binding pocket in response to a series of homologous ligands.1 Even while using enhanced sampling techniques, we demonstrate that the predicted relative binding free energies (RBFE) are sensitive to the initial protein conformational state. Particularly, we highlight the importance of sufficient sampling of protein conformational changes and demonstrate how inclusion of three key protein residues in the ‘hot’ region of the FEP/REST simulation improves the sampling and resolves this sensitivity.
The role of home economics teachers in enhancing adolescents’ food literacy to develop healthy dietary behaviours

Food literacy education is a potential public health strategy to support adolescents to have healthy dietary behaviours. In most high schools in Australia home economics teachers are well positioned to teach food literacy. However, there is limited understanding of the contribution of home economics teachers towards educating adolescents to develop food literacy and healthy dietary behaviours. This study explored high school home economics teachers' understanding of food literacy and their role in developing adolescents' food literacy and healthy dietary behaviours. Qualitative study design was used. Semi-structured interviews were conducted with 22 high school home economics teachers in Australia. The interview questions focused on the teachers' understanding of food literacy, their background in food literacy, and their role in enhancing adolescents' food literacy and healthy dietary behaviours. Data were analysed using the thematic data analysis method. Overall, home economics teachers displayed an understanding of food literacy that broadly consisted of food and nutrition knowledge and food skills. They discussed two levels of food literacy: basic food skills and macro topics such as environmental sustainability. Many home economics teachers recognised the potential impact of food literacy on food choices and health outcomes. Finally, the teachers also described their responsibility and that of other teachers to be positive role models to further impact on the food literacy and healthy dietary behaviours of adolescents.
An Experimental Facility for Wireless Multi-hop Networks in Future Internet Scenarios

Next to traditional communication systems like servers or routers at the backbone and personal computers or laptops acting as clients, the Future Internet will additionally comprise many so-called smart objects. Most of everyday devices like coffee machines, fridges, or light switches will participate in this Internet of Things (IoT). Small-sized computers will connect these devices to the network by establishing low power wireless links. To achieve this vision various kinds of wireless multi-hop networks (WMHNs) play an important role. During the last years, it has become clear that test bed-based research is mandatory in order to develop suitable protocol implementations and metrics for these networks. In this article, we review network configurations for wireless networks for the IoT. We describe the DES-Test bed at the Freie UniversitÃ¤t Berlin as an experimental facility to study these network configurations. In addition to the infrastructure and software provided by the test bed, we introduce Âµkleos as a micro kernel based operating system for embedded devices. We designed Âµkleos with a special focus on Wireless Sensor Networks (WSNs) to complement our approach to study WMHNs. Âµkleos provides an implementation of 6LoWPAN to interconnect WSNs to IP-based networks.
Multi-level spatial modeling for stochastic distributed robotic systems

We propose a combined spatial and non-spatial probabilistic modeling methodology motivated by an inspection task performed by a group of miniature robots. Our models explicitly consider spatiality and yield accurate predictions on system performance. An agent’s spatial distribution over time is modeled by the Fokker—Planck diffusion model and complements current non-spatial microscopic and macroscopic models that model the discrete state distribution of a distributed robotic system. We validate our models on a microscopic level based on sub-microscopic, embodied robot simulations as well as real robot experiments. Subsequently, using the validated microscopic models as our template, abstraction is raised to the level of macroscopic difference equations. We discuss the dependency of the modeling performance on the distance from the robot origin (drop-off location) and temporal convergence of the team distribution. Also, using an asymmetric setup, we show the necessity of spatial modeling methodologies for environments where the robotic platform underlies drift phenomena.
Bayesian versus robust control approach towards parameter uncertainty in monetary policymaking: how close are the outcomes? Some illustrating evidence from a pre-EMU economies

This paper tries to assess the proximity of the macroeconomic outcomes which could arise from a monetary policymaking process based upon either a robust control or a Bayesian (A la Brainard) approach towards parameter uncertainty. We use a small, structural, backward-looking, aggregate model of the EMU economies as the basis for this empirical exercise. After deriving the optimal feedback rules which correspond to the two approaches that we consider in this study, we assess their relative performances with respect to the behavior of the output gap and the in.ation rate volatilities and compare with the no-uncertainty benchmark case. We are particularly interested in the output-in.ation variability trade-oÂ¤ which is usually associated with the implementation of the optimal monetary policy rule in the literature and in the distortions that the presence of parameter uncertainty and its taking into account via the robust control approach or the Bayesian method may induce to this trade-oÂ¤. The results show that the performances of the rules are not too divergent but they appear to be highly contingent upon the preference parameters in the model, ie the relative weight that the monetary authorities attach to output variability (w.r.t. in.ation variability) in the loss function and the robustness aversion of the policymaker which is associated to the robust control approach. In particular, non-standard shapes of the output-in.ation variability trade-oÂ¤ obtain in the robust control case what may be due to the way the misspeci-. cations associated with the worst case scenario feedback into the structural equations of the model. When the rules are considered within the nominal model, the volatility outcomes appear to be closer to each other.
A novel approach for resolving differences in single-cell gene expression patterns from zygote to blastocyst

Motivation: Single-cell experiments of cells from the early mouse embryo yield gene expression data for different developmental stages from zygote to blastocyst. To better understand cell fate decisions during differentiation, it is desirable to analyse the high-dimensional gene expression data and assess differences in gene expression patterns between different developmental stages as well as within developmental stages. Conventional methods include univariate analyses of distributions of genes at different stages or multivariate linear methods such as principal component analysis (PCA). However, these approaches often fail to resolve important differences as each lineage has a unique gene expression pattern which changes gradually over time yielding different gene expressions both between different developmental stages as well as heterogeneous distributions at a specific stage. Furthermore, to date, no approach taking the temporal structure of the data into account has been presented. Results: We present a novel framework based on Gaussian process latent variable models (GPLVMs) to analyse single-cell qPCR expression data of 48 genes from mouse zygote to blastocyst as presented by (Guo et al., 2010). We extend GPLVMs by introducing gene relevance maps and gradient plots to provide interpretability as in the linear case. Furthermore, we take the temporal group structure of the data into account and introduce a new factor in the GPLVM likelihood which ensures that small distances are preserved for cells from the same developmental stage. Using our novel framework, it is possible to resolve differences in gene expressions for all developmental stages. Furthermore, a new subpopulation of cells within the 16-cell stage is identified which is significantly more trophectoderm-like than the rest of the population. The trophectoderm-like subpopulation was characterized by considerable differences in the expression of Id2, Gata4 and, to a smaller extent, Klf4 and Hand1. The relevance of Id2 as early markers for TE cells is consistent with previously published results. Availability: The mappings were implemented based on Prof. Neil Lawrence's FGPLVM toolbox1; extensions for relevance analysis and including the structure of the data can be obtained from one of the authors' homepage.2 Contact: f.buettner@helmholtz-muenchen.de
An Open-Ended Interview Approach for Studying Cognition and Emotion in Organizations

Abstract I present a way of conducting open-ended interviews that I have used in my own research. Good preparation for interviews includes learning about the interviewee and their context beforehand, developing a list of potential follow-up themes, and various hygiene factors. During the interview, key practices include building psychological safety and earning professional respect, phasing questions appropriately, using various types of elaborating questions, tolerating long pauses, and recognizing that managers are rarely naive interviewees. Analyzing interview data requires being mindful of the content rather than coding it mechanically, using theories to aide interpretation, and getting deeply engaged with the data.
Exploiting the Redundancy in Neural Machine Translation

Neural Machine Translation (NMT) has enjoyed success in recent years, but like many other deep learning domains, typically suffers from over-parameterization, resulting in overfitting and large storage size. We demonstrate the efficacy of weight pruning as a compression and regularization technique. In particular we find that our baseline model can be immediately compressed to 40% of its previous size with no performance loss, indicating a high level of redundancy, and that with retraining, our baseline model can be compressed to 10% of its previous size with some performance improvement. In addition, we investigate the distribution of redundancy in the NMT architecture and the interaction of pruning with other forms of regularization such as dropout.