Miracle-dz/UniFAR-FTUs huggingface dataset:
Biofilm Producing Staphylococcus epidermidis Strains Isolated From Clinical Samples in Tehran, Iran

Background: Staphylococcus epidermidis is well documented as an opportunistic pathogen causing biofilm in patients and healthy individuals. Objectives: The aim of this experimental study was to describe the antibiotic resistance patterns of biofilm producing S. epidermidis strains isolated from clinical samples in Tehran, Iran. Moreover, the role of different genes in biofilm formation was also described. Patients and Methods: A total of 250 S. epidermidis strains were isolated from patients in a private hospital of Tehran, Iran from February to December 2014. The biofilm formation of each strain was determined using combination of qualitative Congo-Red agar and quantitative microtiter plate assay, and presence of different genes involved in control and formation of biofilm was detected by the polymerase chain reaction (PCR). Susceptibility of S. epidermidis strains to 19 antibiotics was examined. Results: The results of the biofilm assay revealed that 82% of strains produced black colonies on Congo red agar plates and 68% were able to attach strongly to polystyrene microplates. One hundred percent, 88%, 84%, 64% and 60% of biofilm-producing strains were resistant to penicillin, cefoxitin, erythromycin, trimethoprim-sulfamethoxazole and kanamycin, respectively. On the other hand, none of the strains showed resistance to vancomycin, linezolid, quinupristin/dalfopristin. The icaA, icaD, aap and atlE genes were detected in all biofilm-producing strains and presence of IS256 transposon was limited to 84% of biofilm positive strains. Conclusions: The results of this study illustrated the high prevalence of antibiotic resistant biofilm-producing S. epidermidis strains in this hospital, which could be a reservoir for antibiotic resistance genes.
Predict-Observe-Explain Tasks in Chemistry Laboratory: Pre-Service Elementary Teachers' Understanding and Attitudes

This study was conducted to investigate the effects of laboratory activities based on predict-observe-explain tasks related to the subjects of “Mixtures, Physical and Chemical Changes, Acids and Bases” on pre-service elementary teachers’ understanding and attitude toward chemistry lesson and chemistry laboratory. For this purpose, the pre-service elementary teachers were randomly assigned to experimental (N=26) and control (N=30) groups. The experimental group was instructed using laboratory activities based on predict-observe-explain task and the control group was taught using traditional cook-book design laboratory activities during ten weeks. For the data collection, a two-tier concept test, attitude toward chemistry lesson scale and attitude toward chemistry laboratory scale were applied before and after the instructions. The results indicated that the pre-service elementary teachers who were trained using laboratory activities based on predict-observe-explain task had significantly higher scores in terms of achievement and attitude toward chemistry lesson and laboratory than those taught by the traditional approach. It was also found that instruction for laboratory activities based on predict-observe-explain task was more successful in remediation of the predetermined alternative conceptions.
On a General Dynamic Programming Approach for Decentralized Stochastic Control

For sequential stochastic control problems with standard Borel measurement and control action spaces, we introduce a very general dynamic programming formulation, establish its well-posedness, and provide new existence results for optimal policies. Our dynamic program builds in part on Witsenhausen's standard form, but with a different formulation for the state, action, and transition dynamics. Using recent results on measurability properties of strategic measures in decentralized control, we obtain a controlled Markov model with standard Borel state and state dependent action sets. This allows for a well-posed formulation for the controlled Markov model for a general class of sequential decentralized stochastic control in that it leads to well-defined dynamic programming recursions through universal measurability properties of the value functions for each time stage. Through this formulation, new existence results are obtained for optimal team policies in decentralized stochastic control. These state that for a static team with independent measurements, it suffices for the cost function to be continuous in the actions for the existence of an optimal policy under mild compactness conditions. These also apply to dynamic teams which admit static reductions with independent measurements through a change of measure transformation. We show through a counterexample that weaker conditions may not lead to existence of an optimal team policy. In particular, the paper presents existence results which complement and generalize those previously reported.
SELECTIVE RESPONSE OF Ty1 TRANSPOSITION TEST TO CARCINOGENS

PESHEVA, M. , O. KRASTANOVA, R. STAMENOVA, P. VENKOV and Tsv. TSVETKOV, 2008. Selective response of Ty1 transposition test to carcinogens. Bulg. J. Agric. Sci., 14: 1-15 The Ty1 assay is a short-term test for detection of carcinogens based on induction the transposition of a geneengineered Ty1 retrotransposon in Saccharomyces cerevisiae cells. Previously, we have shown that Ty1 transposition is induced to positive values of the Ty1 test by a number of laboratory carcinogens, including such that are undetectable by Salmonella, DEL or other short-term tests. Here, we provide evidence that the Ty1 test responds positively in concentration and kinetics experiments to the carcinogens 3-aminotriazole, formaldehyde, urethane, benz(a)pyrene, benz(a)anthracene, to the carcionogenic heavy metals arsenic, hexavalent chromium and to the carcinogenic free bile acids chenodeoxycholic and taurodeoxycholic acids. However, the Ty1 test gives negative values with the non-carcinogenic mutagens 5-bromuracil, benzo(e)pyrene, benz(b)anthracene and anthracene, with the heavy metals cadmium and threevalent chromium and the non-carcinogenic conjugated bile acids lythocholic and taurodeoxycholic acids. Results obtained by using the S. cerevisiae D7 test and the studied compounds make the involvement of enhanced gene conversion in the Ty1 test response not likely, and strongly suggest that the positive answer to treatment with carcinogens is due to enchanced Ty1 transposition. It is concluded that the Ty1 test shows a selective positive response to carcinogens and gives negative values with the studied non-carcinogenic mutagens.
Evolving Technologies and Standards Regulation

The EU mandated a single standard for second generation wireless telecommunications, whereas the US allowed several incompatible standards to battle for market share. Motivated by this example, we argue that a single standard leads to a free riding problem, and thus to a significant decrease in marginal incentives for R&D investment. In this context, keeping two separate standards may be a necessary evil to sustain a high level of R&D expenditures. We also provide conditions such that a non-standardization equilibrium is better for consumers and for society as a whole.
Review article: Quality protein maize (QPM): Genetic manipulation for the nutritional fortification of maize

Cereals are the only source of nutrition for one-third of the world’s population especially in developing and underdeveloped nations of Sub-Saharan Africa and South-east Asia. The three major cereals, rice, wheat and maize constitute about 85% of total global cereals production amounting to about 200 million tonnes of protein harvest annually at an average of 10% protein content, out of which a sizeable proportion goes into human consumption (Shewry, 2007). A major concern in case of developing nations is that in most cases, a single cereals crop is the major food staple and as such the nutritional profile of cereal crops assumes great significance. Grain protein content of cereals has a very narrow range with rice (5.8-7.7%), maize (9-11%), barley (8-15%) and wheat (7-22%) as reported by various workers. In many developing countries of Latin America, Africa and Asia, maize is the major staple food and often the only source of protein. At global level, maize accounts for 15% of proteins and 20% of calories in world food diet. But unfortunately, the nutritional profile of maize is poor as it is deficient in essential amino acids such as lysine, tryptophan and methionine due to a relatively higher proportion of prolamines in maize storage proteins which are essentially devoid of lysine and tryptophan. The reason concerning this is that lysine, tryptophan and threonine are the limiting amino acids in human beings and non-ruminants. Maize is also an important component of livestock feed especially in developed nations where 78% of total maize production goes into livestock feed. Therefore, breeding strategies aimed at improving the protein profile of maize will go a long way in reducing prevalence and persistence of malnutrition in developing world.
Nonlinear dynamo in a short Taylor–Couette setup

It is numerically demonstrated by means of a magnetohydrodynamics code that a short Taylor–Couette setup with a body force can sustain dynamo action. The magnetic threshold is comparable to what is usually obtained in spherical geometries. The linear dynamo is characterized by a rotating equatorial dipole. The nonlinear regime is characterized by fluctuating kinetic and magnetic energies and a tilted dipole whose axial component exhibits aperiodic reversals during the time evolution. These numerical evidences of dynamo action in a short Taylor–Couette setup may be useful for developing an experimental device.
Digital Natives or Not? How do Romanian Adolescents Cross the Boundaries of Internet Common Use

Abstract The present paper challenges the dominance of the digital natives’ agenda and turns its attention to the social context in which Internet usage among adolescents occurs. Findings indicate that even when young people are using the Internet with the same frequency, i.e. every day, the differences among them remain significant. Therefore, it can be argued that considering an entire cohort to be similar in terms of Internet use only due its age is a misconception. The way children make use of the Internet and the gratifications they gain after using it depend, as van Dijk (2005) showed, on the quality of access, on the level of skills, and on the personal (e.g. Experience, self-efficacy, confidence) and positional resources (e.g. Age, gender, socio-economic status). Questioning the main determinants that lead to the most advanced way to make use of the Internet, the logistic analysis shows that, in order for a Romanian adolescent to turn into an experienced user once he or she embedded the Internet in his or her everyday life, is a matter of skills, experience, and time online, and is less a matter of socioeconomic background. However, we have to keep in mind the previous path analysis’ findings, which emphasize that online experience, time spent online, self-efficacy, and digital skills are all determined, through direct or indirect effects, by demographic variables (i.e. age, gender and socio-economic status), even when age is held constant (Fizesan [Balea], 2012).
ON THE BURNING CHARACTERISTICS OF COLLISION-GENERATED WATER/HEXADECANE DROPLETS

The combustion characteristics of freely falling droplets, individually generated by the merging of colliding water and hexadecane droplets, were investigated and compared with those for pure hexadecane and emulsified water/hexadecane droplets. The merging of the nominally nonmiscible hexadecane and water was manifested either in an apparently adhesive manner, or with the water droplet inserting into the hexadecane droplet. The latter, however, is the prevalent mode in hot environments and/or for droplet burning, provided the water volume fraction is less than 0.54 so it can be completely covered by hexadecane. Results on the combustion characteristics show that the ignition delay increases with increasing water content that for the same droplet size it varies with t ig (hexadecane) < t ig (collision-generated) < t ig (emulsion) that the flame characteristics, including its color, were not affected by the water content that droplet burning was terminated with either complete combustion, extinction, or microexplosion and that the droplet volume at microexplosion is almost the same as the initial volume of water in the merged droplet. These results, together with considerations of the limit of superheat of water and the attainable droplet temperature, suggest that hexadecane was the primary and possibly only component undergoing gasification and subsequently combustion prior to the occurrence of microexplosion, and that microexplosion was predominantly induced by flash vaporization of the superheated water when it was exposed to the gaseous environment upon the near-complete gasification of the enveloping hexadecane component, instead of through homogeneous nucleation of the water component when it was still enveloped by hexadecane. With the aid of microexplosion, the effective burning rate K eff increased with increasing water content and for a given droplet size exhibited the ranking K eff (collision-generated) > K eff (emulsion) > K eff (hexadecane). The role of the air bubbles entrapped upon coalescence of the colliding droplets in facilitating microexplosion is also discussed.
Empirical validation of the team work engagement construct

This article presents an empirical validation of the construct of team work engagement. Two different samples were used to test the hypotheses. Results from convergent and discriminant validity are presented as well as confirmatory factor analysis that explores the construct's factor structure. Results support the idea that team- and individual-level work engagement are two different, yet related, constructs. However, data do not support the factorial invariance across levels: At the team level, the 1-factor structure, and not the 3-factor one, seems to be the one that best fits the data. This is a necessary first step for future research providing a justification for further analyzing the importance of team work engagement and its relationship with other variables, namely with team effectiveness. A rich body of literature from the last decade has converged on the relevance of the relationship between work engage- ment (WE) and individual performance and well-being (e.g., Halbesleben, 2010; Schaufeli & Bakker, 2003). It is also well acknowledged that job resources (e.g., autonomy, feedback) facilitate the development of WE and buffer the negative effects of job demands such as rapid work pace and inefficient equipment (Bakker & Demerouti, 2007). Most of the studies on WE were conducted at the individual level. However, many people work in teams and need to interact with others in order to perform their tasks. Do the specific dynamics of working within a group of people collectively impact the levels of energy and motivation of employees? In this article we investigate whether team work engagement (TWE) exists as a construct that is qual- itatively different from work engagement at the individual level. We expect that the two constructs are related, yet dif- ferent. This paper may contribute to the literature in two ways. First, although TWE has been used in previous stud- ies (e.g., Bakker, Van Emmerik, & Euwema, 2006; Salano- va, Llorens, Cifre, Martinez, & Schaufeli, 2003; Torrente, Salanova, Llorens, & Schaufeli, 2012a, 2012b) it is still unknown whether it is empirically distinct from individual WE. Second, as a methodological contribution, this study proposes a different operationalization of TWE, measuring it as a team property (by using ''we'' as the referent of the items). Finally, we compare two methods for measuring collective constructs: The aggregation of individual answers and a single score obtained through group discussion.
NBER WORKING PAPER SERIES ACCOUNTING FOR THE RISE IN COLLEGE TUITION

We develop a quantitative model of higher education to test explanations for the steep rise in college tuition between 1987 and 2010. The framework extends the quality-maximizing college paradigm of Epple, Romano, Sarpca, and Sieg (2013) and embeds it in an incomplete markets, life-cycle environment. We measure how much changes in underlying costs, reforms to the Federal Student Loan Program (FSLP), and changes in the college earnings premium have caused tuition to increase. All these changes combined generate a 106% rise in net tuition between 1987 and 2010, which more than accounts for the 78% increase seen in the data. Changes in the FSLP alone generate a 102% tuition increase, and changes in the college premium generate a 24% increase. Our findings cast doubt on Baumol’s cost disease as a driver of higher tuition. Grey Gordon Indiana University Wylie Hall 100 S Woodlawn Ave Bloomington, IN 47405-7104 greygordon@gmail.com Aaron Hedlund University of Missouri 118 Professional Building Columbia, MO 65211 hedlunda@missouri.edu Accounting for the Rise in College Tuition∗ Grey Gordon† Aaron Hedlund‡
Coordinating Voters against Criminal Politicians : Evidence from a Mobile Experiment in India

Adverse selection to political office is now a salient concern in some mature democracies, but it is commonplace in the developing world. In India, 9 percent of legislators face charges for murder, kidnapping, rape, or armed robbery. Using a field experiment in the context of the 2017 Uttar Pradesh state assembly elections, we test the theory that criminal politicians are elected in part because voters lack information to screen for and coordinate on good candidates. We partnered with three major Indian telecom companies to conduct a mobile-based voter information experiment across more than 3,800 villages. Approximately 450,000 mobile subscribers in treatment villages received a voice and text message informing them about the criminal charges against candidates in their constituency. We find that voters respond to the content of the information provided – votes for candidates with severe charges drop by 7.7 percent and votes for candidates with no charges increase by 6.7 percent. In addition, overall turnout increases by 1.6 percent. Effects are strongest when the information is coupled with a coordination treatment, in which individuals are informed that many other voters are also receiving the message. The results suggest that voter frictions such as information asymmetry and coordination failure may cause bad political equilibria to persist. ∗Siddharth Eapen George, siddharthgeorge@fas.harvard. edu, Harvard University; Sarika Gupta, sarikagupta@fas.harvard. edu, World Bank; Yusuf Neggers, yneggers@umich.edu, University of Michigan. We thank our research partner Manoj Kumar at the Center for Governance and Development in India for deep institutional knowledge about election campaigns in Uttar Pradesh, and for invaluable support in implementing the experiment. We are indebted to our advisor Rohini Pande for her extensive support and advice throughout this project. We would also like to thank Abhijit Banerjee, Robert Bates, Kirill Borusyak, Emily Breza, Melissa Dell, Ryan Enos, Michael Kremer, Horacio Larreguy, Filip Matejka, Eduardo Montero, Vincent Pons, Nishith Prakash, Pia Raffler, Gautam Rao, Deepak Saraswat, Andrei Shleifer, Shashank Sreedharan, Henrik Sigstad, and Edoardo Teso for useful feedback and helpful conversations. We thank seminar participants at Harvard and Brown for useful feedback and ideas. Financial support from the J-PAL Governance Initiative, the Harvard Lab for Economic Applications and Policy, and the Watson Institute for International and Public Affairs at Brown University is gratefully acknowledged.
Changing rainfall and anthropogenic-induced flooding: Impacts and adaptation strategies in Benin City, Nigeria

Monthly air temperature and rainfall data of Benin City for 69 years (1941-2009) were collected from the archives of the Nigerian Meteorological Agency, Lagos. Mean annual temperatures, rainfall and standardized anomalies were computed and graphically depicted. A total of 200 structured questionnaires and field observation were designed to collect data on the causal factors and impacts of flooding as well as the adaptation strategies by people in 5 selected flood areas in the city. The results show evidence of global warming around 1978 with a corresponding above normal rainfall, particularly since 1988. The perceived causes of flooding in the selected flood areas are mainly increasing rainstorms, obstruction and absence of drainage systems, disruption of socio-economic activities, loss of properties, inaccessibility and reduction of the aesthetic quality of the environment largely form the impacts of flooding. The adaptive measures in place include emigration, construction of wooden bridges and elevated shops, embankments, construction of raised pedestrian ways with old vehicle tires filled with sand, use of netted doors, windows and rubber footwear. The need for appropriate drainage channels in Benin City is recommended as more lasting solution. Key words: Rainfall intensity, flooding, impacts, adaptation, Benin City, Nigeria.
On Semiparametric Exponential Family Graphical Models

We propose a new class of semiparametric exponential family graphical models for the analysis of high dimensional mixed data. Different from the existing mixed graphical models, we allow the nodewise conditional distributions to be semiparametric generalized linear models with unspecified base measure functions. Thus, one advantage of our method is that it is unnecessary to specify the type of each node and the method is more convenient to apply in practice. Under the proposed model, we consider both problems of parameter estimation and hypothesis testing in high dimensions. In particular, we propose a symmetric pairwise score test for the presence of a single edge in the graph. Compared to the existing methods for hypothesis tests, our approach takes into account of the symmetry of the parameters, such that the inferential results are invariant with respect to the different parametrizations of the same edge. Thorough numerical simulations and a real data example are provided to back up our results.