Miracle-dz/UniFAR-FTUs huggingface dataset:
A drift diffusion model of biological source seeking for mobile robots

Braitenberg vehicles have been used in multiple real world robotic implementations of bio-inspired local navigation. While sensor based control strategies — including existing models of Braitenberg vehicles — typically neglect sensor noise, real robot implementations suffer from different levels of noise, especially in the case of low cost robots and highly stochastic environments. This paper presents a novel drift-diffusion model of Braitenberg vehicle 3a — a bio-inspired source seeking controller for non-holonomic robots — accounting for the sensor noise. The stochastic differential equations obtained provide means to accurately simulate the behaviour of this bio-inspired control mechanism. Although these equations do not have analytic solutions in general, under some simplifying assumptions, we obtain the deterministic equations for the average and dispersion of the vehicles while performing source seeking. Moreover, we found an analytic bound for the distribution of the heading direction of the robots. Simulations illustrate and confirm the theoretical results presented.
Chemical constituents of Swertia longifolia Boiss. with α-amylase inhibitory activity

α-Amylase inhibitors play a critical role in the control of diabetes and many of medicinal plants have been found to act as α-amylase inhibitors. Swertia genus, belonging to the family Gentianaceae, comprises different species most of which have been used in traditional medicine of several cultures as antidiabetic, anti-pyretic, analgesic, liver and gastrointestinal tonic. Swertia longifolia Boiss. is the only species of Swertia growing in Iran. In the present investigation, phytochemical study of S. longifolia was performed and α-amylase inhibitory effects of the plant fractions and purified compounds were determined. Aerial parts of the plant were extracted with hexane, chloroform, methanol and water, respectively. The components of the hexane and chloroform fractions were isolated by different chromatographic methods and their structures were determined by 1H NMR and 13C NMR data. α-Amylase inhibitory activity was determined by a colorimetric assay using 3,5-dinitro salysilic acid. During phytochemical examination, α-amyrin, β-amyrin and β-sitosterol were purified from the hexane fraction, while ursolic acid, daucosterol and swertiamarin were isolated from chloroform fraction. The results of the biochemical assay revealed α-amylase inhibitory activity of hexane, chloroform, methanol and water fractions, of which the chloroform and methanol fractions were more potent (IC50 16.8 and 18.1 mg/ml, respectively). Among examined compounds, daucosterol was found to be the most potent α-amylase inhibitor (57.5% in concentration 10 mg/ml). With regard to α-amylase inhibitory effects of the plant extracts, purified constituents, and antidiabetic application of the species of Swertia genus in traditional medicine of different countries, S. longifolia seems more appropriate species for further mechanistic antidiabetic evaluations.
Perceptions of Self and Short Stature: Effects of Two Years of Growth Hormone Treatment

A cohort study was carried out to determine whether childrens' perception of the problem of short stature changed over 2 years of growth hormone (GH) therapy. A total of 66 children (age range, 5–15 years; mean 10.2 years) were selected on the basis of height below the 3rd centile for chronological age, height velocity below the 25th centile for bone age, prepubertal status, and absence of any organic condition causing growth failure or likely to interfere with GH action. The children were taking part in a 2‐year multicentre trial to assess the effect of authentic recombinant GH on short, slowly growing children without Gil deficiency (GHD). The childrens' and parents' attitudes and emotional adjustment to shortness were assessed before GH therapy commenced, and at 6 months and 2 years, using a growth‐specific psychological instrument, the Attitude to Growth scale (ATG). The children were also assessed using the Piers Harris Children Self Concept Scale at 2 years. The mean ATG scores increased from 34.2 (95% confidence interval, 33.2–35.2) at intake to 37.2 (95% confidence interval, 36.2–38.2) at 2 years. Younger subjects had a greater increase (p < 0.05). No sex differences occurred. Two separate factors were identified in the childrens' attitudes: emotional preoccupation with stature and a concrete focus on practical aspects. No differences were present between childrens' and parents' mean scores, though parents' estimates differed on selected items. The mean Piers Harris score at 2 years was within the normal range, and was positively correlated to the ATG but was unrelated to height. It is concluded that GH treatment may have a beneficial effect on childrens' attitudes to being short, particularly in the younger child. It is recommended that parents undergo careful evaluation before their children are offered long‐term treatment with GH, so that their understanding of their child's perceptions is clarified, and their own hopes and expectations of treatment become realistic and supportive to the child.
R&D Investments and Firm Performance: An Empirical Investigation of the High Technology Sector (Software and Hardware) in the E.U.

Purpose – The purpose of this paper is to examine the relationship among research and development expenses (R&D), market value and firm performance. Additionally, what is also questioned is, whether the relationship between R&D and market value of the firm is linear. Design/methodology/approach – Data analysis was realized through panel data analysis and the feasible generalized square method (FGLS), using data from the financial statements of 39 European firms, which activate in the Software and Hardware Computer sector, for the period 2006-2010. Following prior studies, our dependent variables are the Market Value and Annual Return on Assets (ROA). Findings – Results indicate a positive correlation between R&D investment and firm performance in the marketplace. In contrast, the above does not apply in the case of R&D and firm performance, since due to time lag, the relationship with the ROA results in being negative. Furthermore, a non-linear relationship between R&D and market value of the firm is verified. Research limitations/implications – There are limitations because many firms either they do not accurately calculate or they do not record their R&D investments in their financial statements. Originality/value – The verification of the existence of a non-linear relationship between R&D investments and market value of firms, adds an innovative character in this research.
Piecewise-Linear H∞ Inventory Control of Switched Production Systems

This paper focuses on the problem of inventory control of production systems. The main contribution of the paper is that production systems are modeled as constrained switched linear systems and the inventory control problem is formulated as a constrained switched H∞ problem with a piecewise-affine (PWA) control law. The switching variable for the production systems modeled in this paper is the stock level. When the stock level is positive, some of the perishable produced parts are being stored and will deteriorate with time at a given rate. When the stock level is negative it leads to backorders, which means that orders for production of parts are coming in and there are no stocked parts to immediately meet the demand. A state feedback controller that forces the stock level to be kept close to zero (sometimes called a just-in-time policy), even when there are fluctuations in the demand, will be designed in this paper using H∞ control theory and will be formulated as a set of linear matrix inequalities (LMIs). A numerical example is provided to show the effectiveness of the proposed method
A sensorless control method for capacitor voltage balance and circulating current suppression of modular multilevel converter

There are several problems in the Modular Multilevel Converter (MMC), such as the appearance of circulating current, capacitor voltage unbalance and the requirement for a high number of sensors. All these problems will decrease the reliability and raise the cost/uncertainty of using MMC solutions. As a result, a sensorless control method is proposed in this paper, which targets to improve the performances of MMC in respect to the above mentioned disadvantages: To decrease the cost and simplify the physical implementation, a state observer is proposed and designed to estimate both the capacitor voltages and the circulating currents in order to replace the high numbers of sensors. Furthermore, a control method combining the circulating current suppression and the capacitor voltage balancing is conducted based on the proposed state observer. It is concluded that the proposed state observer and control method can easily be implemented and its effectiveness are verified by some simulation results.
Microdeletions of AZFc Region in Infertile Men with Azoospermia and Oligoasthenoteratozoospermia

Abstract Considerable progress has been made to study the pathophysiology of male infertility in the last few years. About 10-15% of genetic causes such as chromosomal abnormality, single gene and multifactorial mutations may be a causative factor. Submicroscopic microdeletions on chromosome Y is considered to be the most frequent genetic defects associated with impaired spermatogenesis. Therefore, the aim of this present study was to assess pregnancy outcome of intracytoplasmic sperm injection (ICSI) in infertile men from 285 study subjects; fertile controls (n=110) and cases (n=175) with sperm count less than 5 millions/ml [azoospermia (n=150) and oligoasthenoteratozoospermia (n=25)]. Microdeletions located on chromosome Y-sY84, sY86 (AZFa), sY127, sY134 (AZFb), and sY254, sY255 (AZFc) were confirmed with Polymerase Chain Reaction (PCR). A 12.56% was observed in infertile men in one or more STS with a percentage of 1.14, 2.28, 9.14 for AZFa, b and c respectively. The azoospermia factor region c (AZFc) loci showed an increase in frequency when compared to AZFb and a regions. Intracytoplasmic Sperm Injection (ICSI) could be offered or an alternative method to patients with AZFc deletion.
Idiosyncratic Risk and Risk Taking Behavior of Mutual Fund Managers

I propose that various measures of mutual funds’ performance are more consistent with their investment capability when mutual funds present low idiosyncratic risks. This paper finds conditional predictor for funds’ returns: alpha predicts returns positively for low idiosyncratic risk funds. It suggests that mutual funds which showed high alpha and low idiosyncratic risk in the past may be capable in investment. Their performance is consistently higher than funds with low idiosyncratic risk and low alpha. On the other hand, the performance of high idiosyncratic risk funds is more likely to reverse in the future: expected returns are low for high alpha funds, and low alpha funds’ expected returns are high. I split the sample into 3 categories: funds with high idiosyncratic risk, low idiosyncratic risk and low alpha, low idiosyncratic risk and high alpha. Following Barras, Scaillet and Wermer(2010)’s method, I find out that the proportion of zero-alpha fund is highest within high idiosyncratic risk funds, and low alpha low idiosyncratic risk funds include the most unskilled funds. This paper also studies the predictive power of a variety of fund characters: alpha, idiosyncratic risk exposure, information ratio, and so on. However, none of them shows clear predictive pattern for expected returns. My observation reveals that information ratio does not predict returns in the full sample, but it indeed has strong predictive power for funds which keep long term growth, or growth and income investment objective.
Managing historic resources in active farming landscapes: National priorities and local practices

Purpose – To counteract processes of landscape deterioration, marginalisation and loss of cultural heritage due to rural restructuring of farming in late-modern Norwegian society, an agricultural landscape scheme started up in 2009. The purpose of this paper is to examine the way this recently introduced strategy of directing particular resources to a group of selected agricultural landscapes contributes in instigating integrated landscape management and to gain insight in the role cultural heritage play. Design/methodology/approach – The authors ask how potential conflicts between local interpretations of cultural heritage and the assessments made by authoritative heritage managers are expressed in the initial planning documents. Findings – While the reasoning and selection of the two areas are strongly influenced by the authoritative heritage discourse, the agricultural landscape scheme is nonetheless open to local adaptations and adjustments, and the two plans vary both in form and contents due to the .
CluMix : Clustering and Visualization of Mixed-Type Data

In real data situations various factors of interest are measured on different scales, e.g. quantitative gene expression values and categorical clinical features like gender, disease stage etc. In many cases (pre-selected) gene expression data are visualized in heatmaps, while further patient characteristics are only added ”informatively” on top. This can be visually quite confusing in case there are more than just a few such additional features. Also, it might be of interest to include clinical information in the process of clustering patients. Further, by standard heatmaps relationships between the quantitative features used for clustering and the information added on top are not explored explicitely. This package offers an integrative heatmap for data of mixed types to overcome those limitations of classical heatmaps. In order to create a heatmap for variables measured on different scales, special similarity measures are necessary defining i) distances between subjects (e.g. patients) based on features of different types, and ii) distances between the different variables. Similarities between subjects are measured by Gower’s general similarity coefficient [2] with an extension of Podani [4] for ordinal variables. Similarities between variables can be calculated in three ways: i) by combination of appropriate measures of association for different pairs of data types [3], ii) based on distance correlation [3], and iii) by the ’ClustOfVar’ approach [1]. For i) and ii) standard hierarchical clustering is applied to the derived (dis)similarity matrices, with by default Ward’s minimum variance method (corresponding to
Disappearing dividends: the case of Thai listed firms

The Stock Exchange of Thailand (SET) is an important source of funds for firms and provides opportunities for investors. However, the economic boom of 1990-1996, the Asian Economic Crisis and the recession of 1997-2002 have affected the performance of firms listed at SET. The dividend policies of listed firms have also been influenced by these fluctuations in the business cycle. This study investigates the phenomenon of disappearing dividends in the developing capital market of Thailand. It adopts a similar methodology to Fama and French (2001) by classifying listed firms in line with changes in their dividend polices over the period 1990 to 2002. More specifically, the study explores the characteristics of firms which pay dividends, non-payers, former payers and firms which have never paid dividends. These characteristics include profitability, investment opportunities and firm size. The analysis uses firm characteristics for predicting the dividend policies of listed firms. Changes in firm characteristics and the propensity to pay dividends are identified in this process. The analysis suggests that firms which pay dividends tend to be large and highly profitable, although they possess low investment opportunities. The study also suggests that the characteristics of firms which paid dividends changed slightly before the crisis of 1997 and changed markedly during the crisis. However, after the crisis (1998-2002) the characteristics of firms are similar to those observed before the crisis. This result is attributed to the fact that some firms have resumed paying dividends after briefly ceasing this payment during the crisis. More importantly, when firm characteristics are held constant, the propensity to pay dividends of listed firms declined slightly before the crisis and declined strongly after the crisis. Consequently, the majority of new firms and many mature firms do not pay dividends. The findings of this study are consistent with the results of Fama and French (2001), particularly with regard to the characteristics of firms and changes in the propensity to pay dividends. However, this study extends the knowledge on the phenomenon of disappearing dividends by focussing on a developing economy, Thailand. Finally, this study suggests that investors should consider the characteristics of firms, changes in these characteristics and the propensity to pay dividends when identifying opportunities for investment.
Baseline serum albumin is a predictive biomarker for patients with advanced pancreatic cancer treated with bevacizumab: A pooled analysis of 7 prospective trials of gemcitabine‐based therapy with or without bevacizumab

Phase 3 studies of bevacizumab in patients with advanced pancreatic cancer (APCA) demonstrated no improvement in outcome. To the authors' knowledge, no validated predictive biomarkers for bevacizumab exist, although emerging data suggest that subsets of patients with APCA may benefit from treatment with bevacizumab. The authors evaluated baseline serum albumin (b‐alb) as a predictive biomarker in a pooled analysis from 7 prospective clinical trials of gemcitabine‐based therapy with or without bevacizumab.
Effects of Human Capital and Social Capital on Entrepreneurial Activity

We use a knowledge-based perspective in examining the effects of individuals’ human capital and social capital on the likelihood to engage in new venture creation. Our analyses are based on data collected for the 2002 Global Entrepreneurship Monitor. More specifically, we analyzed data from 4536 individuals (living in Belgium or Finland) in terms of their education and skills, and their contacts with the entrepreneurial community. We found that skills specific to the start-up process and knowing an existing entrepreneur increase the likelihood the launch a new venture. We discuss our findings and provide directions for future research.
Wireless passive sensor for pH monitoring inside a small bioreactor

A wireless passive pH sensor for continuous remote bioprocess monitoring is presented. The sensor is small enough to fit inside a small bioreactor or test tube. It consists of a planar spiral inductor connected in parallel to a varactor forming a LC resonant circuit. A pH combination electrode made of an iridium/iridium oxide sensing electrode and a silver/silver chloride reference electrode, is connected in parallel to the varactor. As the medium pH changes, the voltage across the electrodes varies, shifting the resonant frequency of the sensor. For in-fluid monitoring the sensor is hermetically sealed to encapsulate, and reduce parasitic capacitive coupling and eddy current loss. The resonant frequency of the sensor is tracked remotely by an interrogator inductor inductively coupled to the sensor. The sterilizable sensor was used for remote pH monitoring of Yarrowia lipolytica fermentation in a shake flask over 67 hours. Experiment shows that the medium pH can be monitored with 2.46 MHz/pH sensitivity and maximum deviation of 0.07 pH from a commercial pH probe measurement over a 6.55. 26 pH range.
Circular Business Model Innovation: A process framework and a tool for business model innovation in a circular economy

The Master’s programme Industrial Ecology is jointly organised by Leiden University and Delft University of Technology. Companies need new business models to grasp the opportunities of a circular economy. This thesis investigates to what extent existing frameworks, methods and tools for business model innovation are useful to cope with the challenges of designing and implementing circular business models. To innovate towards a circular business model, the use of a new framework and tool is recommended. The Circular Business Model Innovation framework outlines a process of 18 typical obstacles – or challenges – which should be taken into account. The Business Cycle Canvas supports practitioners to think in systems and develop supply chains with a closed material loop, one the most important challenges when designing a circular business model.
Inhibition of the OCTN2 carnitine transporter by HgCl2 and methylmercury in the proteoliposome experimental model: insights in the mechanism of toxicity

Mercury causes toxic effects in many tissues interacting with protein cysteine (Cys) thiols. Transport systems represent critical targets of mercurials. Indeed, the majority of transport systems of higher eukaryotes contain several Cys residues. One of the most up to date method of studying transport is the reconstitution of transporters in proteoliposomes. This method has been used as a useful approach to test the effect of HgCl2 and methylmercury (MeHg) on the carnitine (OCTN2) transporter. OCTN2, extracted from kidney brush border membranes with 3% octaethylene glycol monododecyl ether (C12E8), was reconstituted in liposomes by removing the detergent with hydrophobic chromatography columns. Transport was measured as [3H]carnitine uptake into proteoliposomes containing carnitine (antiport reaction). Mercurials strongly inhibited the antiport. Inhibition was reversed by 1,4-dithioerythritol, L-cysteine (Cys), and N-acetyl-L-cysteine (NAC) indicating that it was caused by covalent reaction of mercurials with Cys residue(s). The IC50 for HgCl2, and MeHg were 2.5 and 7.4 µM, respectively. Kinetic studies showed non competitive or mixed inhibition for HgCl2 or MeHg with Ki of 4.2 and 13 µM, respectively. The presence of substrate prevented the inhibition indicating that the mercurial binding residue (Cys) is in the substrate binding site. Efflux of carnitine from proteoliposomes was trans-stimulated, not inhibited, by higher concentrations (500 µM) of extraliposomal MeHg and HgCl2. Differently, no effects on uptake of carnitine were exerted by mercurials present in the internal compartment of the proteoliposomes. The results allowed gaining new insights in the molecular mechanism of inhibition and of mercurial toxicity.
Spin-flip model of spin-polarized vertical-cavity surface-emitting lasers: Asymptotic analysis, numerics, and experiments

© 2015 American Physical Society. The spin-flip model describing optically pumped spin-polarized vertical-cavity surface-emitting lasers is considered. The steady-state solutions of the model for elliptically polarized fields are studied. Asymptotic analysis for the existence and stability of the steady-state solutions is developed, particularly in the presence of pump polarization ellipticity. The expansion is with respect to small parameters representing the ellipticity and the difference between the total pump power and the lasing threshold. The analytical results are then confirmed numerically, where it is obtained that generally one of the steady-state solutions is stable while the other is not. The theoretical results are shown to be in qualitative agreement with the experiments.