3,030 research outputs found
Antimicrobial resistance characteristics and fitness of Gram-negative fecal bacteria from volunteers treated with minocycline or amoxicillin.
A yearlong study was performed to examine the effect of antibiotic administration on the bacterial gut flora. Gram-negative facultative anaerobic bacteria were recovered from the feces of healthy adult volunteers administered amoxicillin, minocycline or placebo, and changes determined in antimicrobial resistance (AMR) gene carriage. Seventy percent of the 1039 facultative anaerobic isolates recovered were identified by MALDI-TOF as Escherichia coli. A microarray used to determine virulence and resistance gene carriage demonstrated that AMR genes were widespread in all administration groups, with the most common resistance genes being bla TEM, dfr, strB, tet(A), and tet(B). Following amoxicillin administration, an increase in the proportion of amoxicillin resistant E. coli and a three-fold increase in the levels of bla TEM gene carriage was observed, an effect not observed in the other two treatment groups. Detection of virulence genes, including stx1A, indicated not all E. coli were innocuous commensals. Approximately 150 E. coli collected from 6 participants were selected for pulse field gel electrophoresis (PFGE), and a subset used for characterisation of plasmids and Phenotypic Microarrays (PM). PFGE indicated some E. coli clones had persisted in volunteers for up to 1 year, while others were transient. Although there were no unique characteristics associated with plasmids from persistent or transient isolates, PM assays showed transient isolates had greater adaptability to a range of antiseptic biocides and tetracycline; characteristics which were lost in some, but not all persistent isolates. This study indicates healthy individuals carry bacteria harboring resistance to a variety of antibiotics and biocides in their intestinal tract. Antibiotic administration can have a temporary effect of selecting bacteria, showing co-resistance to multiple antibiotics, some of which can persist within the gut for up to 1 year
Multi Visualization and Dynamic Query for Effective Exploration of Semantic Data
Semantic formalisms represent content in a uniform way according to ontologies. This enables manipulation and reasoning via automated means (e.g. Semantic Web services), but limits the userās ability to explore the semantic data from a point of view that originates from knowledge representation motivations. We show how, for user consumption, a visualization of semantic data according to some easily graspable dimensions (e.g. space and time) provides effective sense-making of data. In this paper, we look holistically at the interaction between users and semantic data, and propose multiple visualization strategies and dynamic filters to support the exploration of semantic-rich data.
We discuss a user evaluation and how interaction challenges could be overcome to create an effective user-centred framework for the visualization and manipulation of semantic data. The approach has been implemented and evaluated on a real company archive
Annihilation-Gamma-based Diagnostic Techniques for Magnetically Confined Electron-Positron Pair Plasma
Efforts are underway to magnetically confine electron--positron pair plasmas
to study their unique behavior, which is characterized by significant changes
in plasma time and length scales, supported waves, and unstable modes. However,
use of conventional plasma diagnostics presents challenges with these
low-density and annihilating matter-antimatter plasma. To address this problem,
we propose to develop techniques based on the distinct emission provided by
annihilation. This emission exhibits two spatial correlations: the distance
attenuation of isotropic sources and the back-to-back propagation of
momentum-preserving 2- annihilation. We present the results of our
analysis of the emission rate and the spatial profile of the
annihilation in a magnetized pair plasma from direct pair collisions, from the
formation and decay of positronium, as well as from transport processes. In
order to demonstrate the effectiveness of annihilation-based techniques, we
tested them on annular emission profiles produced by a
radioisotope on a rotating turntable. Direct and positronium-mediated
annihilation result in overlapping volumetric sources, and the
2- emission from these volumetric sources can be tomographically
reconstructed from coincident counts in multiple detectors. Transport processes
result in localized annihilation where field lines intersect walls, limiters,
or internal magnets. These localized sources can be identified by the
fractional counts on spatially distributed detectors.Comment: 21 pages, 11 figures, 2 tables, contribution to the 13th
International Workshop on Non-Neutral Plasma
Labor Market Effects of Immigration - Evidence from Neighborhood Data
This paper combines individual-level data from the German Socio-Economic Panel (SOEP) with economic and demographic postcode-level data from administrative records to analyze the effects of immigration on wages and unemployment probabilities of high- and low-skilled natives. Employing an instrumental variable strategy and utilizing the variation in the population share of foreigners across regions and time, we find no support for the hypothesis of adverse labor market effects of immigration.In diesem Papier werden Individualdaten des Sozio-Ćkonomischen Panels (SOEP) mit ƶkonomischen und demographischen Informationen auf Postleitzahlebene aus administrativen Daten verknĆ¼pft, um den Effekt von Zuwanderung auf Lƶhne und die Wahrscheinlichkeit von Arbeitslosigkeit von niedrig- und hochqualifizierten Einheimischen zu analysieren. Unter Verwendung eines Instrumentvariablenansatzes und unter Ausnutzung der regionalen und zeitlichen Variation des Anteils von AuslƤndern in der Bevƶlkerung unterstĆ¼tzen unsere Ergebnisse nicht die Hypothese, dass Zuwanderung negative Auswirkungen auf den Arbeitsmarkterfolg von Einheimischen hat
Two-Point Entanglement Near a Quantum Phase Transition
In this work, we study the two-point entanglement S(i,j), which measures the
entanglement between two separated degrees of freedom (ij) and the rest of
system, near a quantum phase transition. Away from the critical point, S(i,j)
saturates with a characteristic length scale , as the distance |i-j|
increases. The entanglement length agrees with the correlation length.
The universality and finite size scaling of entanglement are demonstrated in a
class of exactly solvable one dimensional spin model. By connecting the
two-point entanglement to correlation functions in the long range limit, we
argue that the prediction power of a two-point entanglement is universal as
long as the two involved points are separated far enough.Comment: published versio
Economics of education research: a review and future prospects
In this paper we offer an appraisal of the economics of education research area, charting its history as a field and discussing the ways in which economists have contributed both to education research and to education policy-making. In particular, we highlight the theoretical and methodological contributions that economists have made to the field of education during the last 50 years. Despite the success of the economics of education as a field of inquiry, we argue that some of the contributions made by economists could be limited if the economics of education is seen as quite distinct from the other disciplines working in the field of education. In these areas of common interest, economists need to work side by side with the other major disciplines in the field of education if their contribution to the field is to be maximised, particularly in terms of applying improved methodology. We conclude that the study of education acquisition and its economic and social impact in the economics of education research area is very likely to remain a fertile research ground. Acknowledgement
Injection of Positrons into a Dense Electron Cloud in a Magnetic Dipole Trap
The creation of an electron space charge in a dipole magnetic trap and the
subsequent injection of positrons has been experimentally demonstrated.
Positrons (5eV) were magnetically guided from their source and injected into
the trapping field generated by a permanent magnet (0.6T at the poles) using a
cross field E B drift, requiring tailored electrostatic and magnetic
fields. The electron cloud is created by thermionic emission from a tungsten
filament. The maximum space charge potential of the electron cloud reaches
-42V, which is consistent with an average electron density of ()
and a Debye length of () .
We demonstrate that the presence of this space potential does not hamper
efficient positron injection. Understanding the effects of the negative space
charge on the injection and confinement of positrons represents an important
intermediate step towards the production of a confined electron-positron pair
plasma
A meta-analysis of the drive for muscularity's relationships with exercise behaviour, disordered eating, supplement consumption, and exercise dependence
We examined the drive for muscularity's (DFM) relationships with exercise behaviour, disordered eating, supplement consumption, and exercise dependence in males. By searching electronic databases, manually reviewing journal tables of contents and retrieved article reference lists, and corresponding with leading researchers, we identified 77 studies. A random effects model was applied to perform analyses and we adjusted results for possible publication bias. The average effect sizes (r) the DFM had with weight training (.31), non-weight training (.11), disordered eating (.30), supplement consumption (.36), and exercise dependence (.43) were significant (P < .05). The relationship between the attitudes and behavioural subscales of the DFM Scale (r = .47) was significant (P < .001). For supplement consumption, moderator analysis indicated that r varied significantly for questionnaire type and participant status (student versus non-student, P < .01). The small to moderate relationships indicate the value of adopting theoretical perspectives allowing the examination of the DFM's role in predicting exercise and dietary behaviour within a broader psychosocial context. Most researchers have studied these relationships in isolation. The relationship between the two DFM subscales implies that the questionnaire total score may better represent a commitment to muscularity rather than a drive per se
ISML: an interface specification meta-language
In this paper we present an abstract metaphor model situated within a model-based user interface framework. The inclusion of metaphors in graphical user interfaces is a well established, but mostly craft-based strategy to design. A substantial body of notations and tools can be found within the model-based user interface design literature, however an explicit treatment of metaphor and its mappings to other design views has yet to be addressed. We introduce the Interface Specification Meta-Language (ISML) framework and demonstrate its use in comparing the semantic and syntactic features of an interactive system. Challenges facing this research are outlined and further work proposed
The second flight of the SUNRISE balloon-borne solar observatory: overview of instrument updates, the flight, the data and first results
The SUNRISE balloon-borne solar observatory, consisting of a 1~m aperture
telescope that provided a stabilized image to a UV filter imager and an imaging
vector polarimeter, carried out its second science flight in June 2013. It
provided observations of parts of active regions at high spatial resolution,
including the first high-resolution images in the Mg~{\sc ii}~k line. The
obtained data are of very high quality, with the best UV images reaching the
diffraction limit of the telescope at 3000~\AA\ after Multi-Frame Blind
Deconvolution reconstruction accounting for phase-diversity information. Here a
brief update is given of the instruments and the data reduction techniques,
which includes an inversion of the polarimetric data. Mainly those aspects that
evolved compared with the first flight are described. A tabular overview of the
observations is given. In addition, an example time series of a part of the
emerging active region NOAA AR~11768 observed relatively close to disk centre
is described and discussed in some detail. The observations cover the pores in
the trailing polarity of the active region, as well as the polarity inversion
line where flux emergence was ongoing and a small flare-like brightening
occurred in the course of the time series. The pores are found to contain
magnetic field strengths ranging up to 2500~G and, while large pores are
clearly darker and cooler than the quiet Sun in all layers of the photosphere,
the temperature and brightness of small pores approach or even exceed those of
the quiet Sun in the upper photosphere.Comment: Accepted for publication in The Astrophysical Journa
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