Pair Of Clusters Research Articles

English

Hot pepper is the dominant vegetable crop grown in different parts of Ethiopia with long history of cultivation and considerable genetic diversity for most important morphological traits. However, shortage of varieties, the prevalence of fungal and bacterial as well as viral diseases, information is lacking on genetic diversity and genetic information to design genetic resource conservation to improve yield and yield components of hot pepper. The study was undertaken to assess the morphological diversity of 64 hot pepper genotypes at Axum Agricultural Research Centre in Mereb Leke District during the year 2017/2018, using 8×8 simple lattice design. Analysis of variance revealed that there were a significant (P<0.01) differences in genetic variation among genotypes for 19 morphological and fruit characters. The genetic distances measured by D2 and Ward's clustering method was grouped (the 64 genotypes) into seven distinct clusters. The maximum and minimum distances were observed between Clusters III and VII (189.09) and clusters I and V (29.24). This indicated the existence of a possibility to improve genotypes through hybridization from pair of clusters and subsequent selection can be made from the segregants generations. Principal component analysis showed that the first five principal component analysis explained about 79.45% of the total variation. Generally, the study confirmed presence of adequate genetic diversity between any pair of clusters which could be exploited for future variety improvement program. Key words: Capsicum, cluster analysis, principal component analysis.  

Long-range entangled-plaquette states for critical and frustrated quantum systems on a lattice

We explore a variational Ansatz for lattice quantum systems---named long-range entangled-plaquette state---in which pairs of clusters of adjacent lattice sites are correlated at any distance. The explicit scale-free structure of correlations built in this wave function makes it fit to reproduce critical states with long-range entanglement. The use of complex weights in the Ansatz allows for an efficient optimization of nonpositive definite states in a fully variational fashion, namely without any additional bias (arising, e.g., from pre-imposed sign structures) beyond that imposed by the parametrization of the state coefficients. These two features render the Ansatz particularly appropriate for the study of quantum phase transitions in frustrated systems. Moreover, the Ansatz can be systematically improved by increasing the long-range plaquette size, as well as by the inclusion of even larger adjacent-site plaquettes. We validate our Ansatz and its optimization procedure in the case of the XX and Heisenberg chain, and further apply it to the case of a simple, yet paradigmatic model of frustration, namely the ${J}_{1}\ensuremath{-}{J}_{2}$ antiferromagnetic Heisenberg chain. For this model we provide clear evidence that our trial wave function faithfully describes both the short-range physics (particularly in terms of ground-state energy) and the long-range one expressed by the Luttinger exponent, and the central charge of the related conformal field theory, which govern the decay of correlations and the scaling of the entanglement entropy, respectively. Finally we successfully reproduce the incommensurate correlations developing in the system at strong frustration, as a result of the flexible representation of sign (phase) structures via complex weights.

Muscle Synergy Analysis for Stroke During Two Degrees of Freedom Reaching Task on Horizontal Plane

This study aimed to investigate muscle synergies from major muscles that contribute to each degree of freedom (DOF) in a low DOF task with trunk restraint during a fundamental reaching task used frequently in daily life. Seven non-patients (controls) and eleven stroke patients (mild or severe groups) in Brunnstrom stage 2–4 recovery were assessed. Subjects performed two DOF reaching tasks requiring motor coordination of the elbow and shoulder on the horizontal plane. Electromyography signals were measured during the task, and muscle synergy data extracted from them were analyzed using cluster analysis. No significant differences were noted between patients with stroke and healthy subjects in terms of the coefficient of determination, R-squared, determined according to the number of modules. Cluster analysis revealed that each of the clusters in the control and mild groups was governed by one channel. However, one cluster in the severe group was governed by two channels. When the clusters of the mild group and the control group were compared, the highest similarities (all values exceeded 0.9) were noted between the corresponding clusters of the two groups. All other similarity values were < 0.8. A similar trend was noted when the severe group clusters were compared with control group clusters; however, only three corresponding pairs of clusters exhibited similarity values exceeding 0.9, while the rest were < 0.8. Muscle synergies during the two DOF reaching tasks with trunk restraint showed differences in extensors between healthy individuals and patients with stroke.

Sinibotia lani, a new species of botiid loach (Teleostei: Botiidae) from Guangxi, China.

Sinibotia lani, a new botiid loach is described from the Zuojiang River, located in Guangxi Autonomous Region, China. The species differs from other members of Sinibotia by a combination of the following morphological characters: body depth 17.5-21.1% SL; snout length shorter than postorbital length of head; eye diameter 10.2-13.2% HL; interorbital width 16.0-18.6% HL; suborbital spine reaching or extending beyond postorbital margin of eye; lower lip with pair of fleshy button-like clusters of papillae; dorsal-fin origin opposite to pelvic-fin origin, pelvic fin not reaching anus; includes six dark vertical bars on the body. A key to the species of Sinibotia is provided.

Particle acceleration in a nearby galaxy cluster pair: the role of cluster dynamics

Context. Diffuse radio emission associated with the intracluster medium (ICM) is observed in a number of merging galaxy clusters. It is currently believed that a fraction of the kinetic energy in mergers is channeled into nonthermal components, such as turbulence, cosmic rays, and magnetic fields, which may lead to the formation of giant synchrotron sources in the ICM. Aims. Studying merging galaxy clusters in different evolutionary phases is fundamental for understanding the origin of radio emission in the ICM. Methods. We observed the nearby galaxy cluster pair RXC J1825.3+3026 (z ∼ 0.065) and CIZA J1824.1+3029 (z ∼ 0.071) at 120 − 168 MHz with the LOw Frequency ARray (LOFAR) and made use of a deep (240 ks) XMM-Newton dataset to study the nonthermal and thermal properties of the system. RXC J1825.3+3026 is in a complex dynamical state, with a primary ongoing merger in the E-W direction and a secondary later stage merger with a group of galaxies in the SW, while CIZA J1824.1+3029 is dynamically relaxed. These two clusters are in a pre-merger phase. Results. We report the discovery of a Mpc-scale radio halo with a low surface brightness extension in RXC J1825.3+3026 that follows the X-ray emission from the cluster center to the remnant of a galaxy group in the SW. This is among the least massive systems and the faintest giant radio halo known to date. In contrast to this, no diffuse radio emission is observed in CIZA J1824.1+3029, nor in the region between the pre-merger cluster pair. The power spectra of the X-ray surface brightness fluctuations of RXC J1825.3+3026 and CIZA J1824.1+3029 are in agreement with the findings for clusters exhibiting a radio halo and clusters where no radio emission has been detected, respectively. Conclusions. We provide quantitative support to the idea that cluster mergers play a crucial role in the generation of nonthermal components in the ICM.

Evolving a Psycho-Physical Distance Metric for Generative Design Exploration of Diverse Shapes

AbstractIn this paper, a generative design approach is proposed that involves the users’ psychological aspect in the design space exploration stage to create distinct design alternatives. Users’ perceptual judgment about designs is extracted as a psycho-physical distance metric, which is then integrated into the design exploration step to generate design alternatives for the parametric computer-aided design (CAD) shapes. To do this, a CAD model is first parametrized by defining geometric parameters and determining ranges of these parameters. Initial design alternatives for the CAD model are generated using Euclidean distance-based sampling teaching–learning-based optimization (S-TLBO), which is recently proposed and can sample N space-filling design alternatives in the design space. Similar designs are then clustered, and a user study is conducted to capture the subjects’ perceptual response for the dissimilarities between the cluster pairs. In addition, a furthest-point-sorting technique is introduced to equalize the number of designs in the clusters, which are being compared by the subjects in the user study. Afterward, nonlinear regression analyses are carried out to construct a mathematical correlation between the subjects’ perceptual response and geometric parameters in the form of a psycho-physical distance metric. Finally, a psycho-physical distance metric obtained is utilized to explore distinct design alternatives for the CAD model. Another user study is designed to compare the diversification between the designs when the Euclidean and the suggested psycho-physical distance metrics are utilized. According to the user study, designs generated with the latter metric are more distinct.

Spectroscopic Characterization of an Eight-Iron Nitrogenase Cofactor Precursor that Lacks the "9th Sulfur".

Nitrogenases catalyze the reduction of N2 to NH4+ at its cofactor site. Designated the M-cluster, this [MoFe7 S9 C(R-homocitrate)] cofactor is synthesized via the transformation of a [Fe4 S4 ] cluster pair into an [Fe8 S9 C] precursor (designated the L-cluster) prior to insertion of Mo and homocitrate. We report the characterization of an eight-iron cofactor precursor (designated the L*-cluster), which is proposed to have the composition [Fe8 S8 C] and lack the "9th sulfur" in the belt region of the L-cluster. Our X-ray absorption and electron spin echo envelope modulation (ESEEM) analyses strongly suggest that the L*-cluster represents a structural homologue to the l-cluster except for the missing belt sulfur. The absence of a belt sulfur from the L*-cluster may prove beneficial for labeling the catalytically important belt region, which could in turn facilitate investigations into the reaction mechanism of nitrogenases.

Spectroscopic Characterization of an Eight‐Iron Nitrogenase Cofactor Precursor that Lacks the “9th Sulfur”

AbstractNitrogenases catalyze the reduction of N2 to NH4+ at its cofactor site. Designated the M‐cluster, this [MoFe7S9C(R‐homocitrate)] cofactor is synthesized via the transformation of a [Fe4S4] cluster pair into an [Fe8S9C] precursor (designated the L‐cluster) prior to insertion of Mo and homocitrate. We report the characterization of an eight‐iron cofactor precursor (designated the L*‐cluster), which is proposed to have the composition [Fe8S8C] and lack the “9th sulfur” in the belt region of the L‐cluster. Our X‐ray absorption and electron spin echo envelope modulation (ESEEM) analyses strongly suggest that the L*‐cluster represents a structural homologue to the l‐cluster except for the missing belt sulfur. The absence of a belt sulfur from the L*‐cluster may prove beneficial for labeling the catalytically important belt region, which could in turn facilitate investigations into the reaction mechanism of nitrogenases.

Machine learning in APOGEE

Context. The vast volume of data generated by modern astronomical surveys offers test beds for the application of machine-learning. In these exploratory applications, it is important to evaluate potential existing tools and determine those that are optimal for extracting scientific knowledge from the available observations. Aims. We explore the possibility of using unsupervised clustering algorithms to separate stellar populations with distinct chemical patterns. Methods. Star clusters are likely the most chemically homogeneous populations in the Galaxy, and therefore any practical approach to identifying distinct stellar populations should at least be able to separate clusters from each other. We have applied eight clustering algorithms combined with four dimensionality reduction strategies to automatically distinguish stellar clusters using chemical abundances of 13 elements. Our test-bed sample includes 18 stellar clusters with a total of 453 stars. Results. We have applied statistical tests showing that some pairs of clusters (e.g., NGC 2458–NGC 2420) are indistinguishable from each other when chemical abundances from the Apache Point Galactic Evolution Experiment (APOGEE) are used. However, for most clusters we are able to automatically assign membership with metric scores similar to previous works. The confusion level of the automatically selected clusters is consistent with statistical tests that demonstrate the impossibility of perfectly distinguishing all the clusters from each other. These statistical tests and confusion levels establish a limit for the prospect of blindly identifying stars born in the same cluster based solely on chemical abundances. Conclusion. We find that some of the algorithms we explored are capable of blindly identify stellar populations with similar ages and chemical distributions in the APOGEE data. Even though we are not able to fully separate the clusters from each other, the main confusion arises from clusters with similar ages. Because some stellar clusters are chemically indistinguishable, our study supports the notion of extending weak chemical tagging that involves families of clusters instead of individual clusters.

Investigating the solid-liquid extraction process of puerarin by molecular dynamics simulations

The solid-liquid extraction is an efficient method to obtain bioactive components from natural medicinal herbs. The diffusion of the bioactive molecule is the key to efficient solid-liquid extraction. The current research aims to investigate the dissolution mechanism and the dispersal behavior of puerarin in the solid-liquid extraction process by molecular dynamics simulations. A cluster including 20 puerarin molecules immersed into the solvent box with 80 Å thicknesses and 5 ns of MD simulations are performed to all systems. The effects of ethanol concentration and extraction temperature on the molecular dispersion efficiency of puerarin are investigated. The simulation results show various dissolution behaviors in different concentration of ethanol solution. Due to the H-bonding interaction between puerarin and solvents, the puerarin molecules can move gradually out of the cluster. To quantitatively describe the diffusion process of puerarin cluster, the RDFs for oxygen-oxygen (O-O) pair of puerarin cluster, the diffusion coefficient of the cluster, and the number of hydrogen bonds and lifetime of hydrogen bonds between puerarin molecules are calculated. The results show that the best condition of dispersion is at 60% of the ethanol concentration and 323.15 K of the system temperature, which can be fitted with the experiment of extraction. This research provides clear images of the dissolution process of drug molecular dispersions at the molecular level. Also, the MD can effectively predict the extraction conditions of the actual experiment.

Search for the evolutionary relationship between Galactic globular and open clusters using data from the Gaia DR2 catalogue

Abstract Passing through the Galactic disc, a massive object such as a globular cluster, can trigger star formation process leading to the birth of open clusters. Here, we analyse such possible evolutionary relationship between globular and open clusters. To search for the closest rapprochement between objects we computed backwards the orbits of 150 Galactic globular and 232 open clusters (younger than 100 Myr) with proper motions, derived from the Gaia DR2 catalogue. The orbits were computed using the recently modified three-component (disc, bulge, and halo) axisymmetric Navarro–Frenk–White potential, which was complemented by non-axisymmetric bar and spiral density wave potentials. We obtained a new estimate for the frequency of impacts of globular clusters about the Galactic disc, which is equal to four events for 1 Myr. In the framework of the considered scenario, we highlight the following nine pairs of globular and open clusters, with rapprochement within 1 kpc at the time of the intersection the Galactic disc by a globular cluster for the latest 100 Myr: NGC 104 – Turner 3, NGC 104 – NGC 6396, NGC 104 – Ruprecht 127, NGC 5139 – Trumpler 17, NGC 5139 – NGC 6520, NGC 6341 – NGC 6613, NGC 6838 – NGC 6520, NGC 7078 – NGC 7063, NGC 6760 – Ruprecht 127.

Halo concentration, galaxy red fraction, and gas properties of optically defined merging clusters

Abstract We present multi-wavelength studies of optically defined merging clusters, based on the Hyper Suprime-Cam Subaru Strategic Program. Luminous red galaxies, tracing cluster mass distributions, enable us to identify cluster subhalos at various merging stages, and thus make a homogeneous sample of cluster mergers that is unbiased with respect to the merger boost of the intracluster medium (ICM). We define, using a peak-finding method, merging clusters with multiple peaks and single clusters with single peaks from the CAMIRA cluster catalog. Stacked weak-lensing analysis indicates that our sample of merging clusters is categorized into major mergers. The average halo concentration for the merging clusters is ∼70% smaller than that of the single-peak clusters, which agrees well with predictions of numerical simulations. The spatial distribution of subhalos is less centrally concentrated than the mass distribution of the main halo. The fractions of red galaxies in the merging clusters are not higher than those of the single-peak clusters. We find a signature of the merger boost of the ICM from the stacked Planck Sunyaev–Zel’dovich effect and ROSAT X-ray luminosity, but not in optical richness. The stacked X-ray surface brightness distribution, aligned with the main subhalo pairs of low-redshift and massive clusters, shows that the central gas core is elongated along the merger axis, and overall gas distribution is misaligned by ∼60°. The homogeneous, unbiased sample of cluster mergers and multi-wavelength follow-up studies provide a unique opportunity to make a complete picture of merger physics over the whole process.

Exploring Wells-Dawson Clusters Associated With the Small Ribosomal Subunit

The polyoxometalate P2W18, the Wells-Dawson cluster, stabilized the ribosome sufficiently for the crystallographers to solve the phase problem and improve the structural resolution. In the following we characterize the interaction of the Wells-Dawson cluster with the ribosome small subunit. There are 14 different P2W18 clusters interacting with the ribosome, and the types of interactions range from one simple residue interaction to complex association of multiple sites including backbone interactions with a Wells-Dawson cluster. Although well-documented that bridging oxygen atoms are the main basic sites on other polyoxometalate interaction with most proteins reported, the W=O groups are the main sites of the Wells-Dawson cluster interacting with the ribosome. Furthermore, the peptide chain backbone on the ribosome host constitutes the main sites that associate with the Wells-Dawson cluster. In this work we investigate the potential of one representative pair of closely-located Wells-Dawson clusters being a genuine Double Wells-Dawson cluster. We found that the Double Wells-Dawson structure on the ribosome is geometrically sound and in line with other Double Wells-Dawson clusters previously observed in the solid state and solution. This information suggests that the Double Wells-Dawson structure on the ribosome is real and contribute to characterization of this particular structure of the ribosome.

Quantification of Genotypic and Chemotypic Diversity for Elite Clone Selection with High-quality Essential Oil Traits in Vetiver [Chrysopogon zizanioides (L.) Roberty

Vetiver (Chrysopogon zizanioides (L.) Roberty (Poaceae) is a perennial herbaceous grass. It is cultivated for the production of high-value essential oil, which imparts a robust and persistent woody odor escorted with different undertones such as earthy, grapefruit-like, flowery, smoked, ambery, etc. The study aims to determine the genotypic and chemotypic diversity in twenty-three genetic stocks of vetiver. The nature, proportion and degree of genetic diversity were evaluated using Mahalanobis D2-statistics on seven agro-economical quantitative traits. All the vetiver accessions were grouped into six clusters wherein, the inter-cluster distance was observed maximum in between I and III cluster pair (117.18) and minimum in II and IV cluster pair (64.98). Among seven economic characters, plant height (59.33 %) was found to be leading contributor toward genetic diversity, followed by essential oil yield (10.43 %). However, root length (2.77 %) showed the lowest contributing character towards genetic diversity. The genetic variability was also studied through percentage chemical constituents present in the essential oils. The result of the present study concluded to enhance the traits of auspicious OPSPs accessions, responsible for high oil yields with specific chemical constituents to meet the market demand of khus essential oil. The accession VS-20 and VS-23 were found to be highly divergent genotypes among all and could be chosen for further exploitation in the hybrid breeding program to develop superior cultivars of vetiver. The clones rich in specific constituent like khusinol (VS-9), khusimol (VS-11) and khusilal (VS-17) and high essential oil could also be selected for further exploitation.

Possible cluster pairing correlation in the checkerboard Hubbard model: a quantum Monte Carlo study

Constrained-path quantum Monte Carlo method is applied to study the pairing correlation in the checkerboard Hubbard model with inhomogeneous nearest-neighbor hopping at a low doping of holes. The inhomogeneous hopping can enhance the pairing correlation among different plaquette clusters. An obvious maximum for the pairing correlation is observed at a certain inhomogeneous hopping. The cluster pairing correlation shows the strongest long-range behavior at the optimal inhomogeneity. The enhancement of cluster pairing correlation might be associated with the transition of the Fermi surface structure. This work indicates that the inhomogeneous hopping could tailor the pairing correlation effectively.

Solution-Processable Superatomic Thin-Films.

Atomically precise nanoscale clusters could assemble into crystalline ionic crystals akin to the atomic ionic solids through the strong electrostatic interactions between the constituent clusters. Here we show that, unlike atomic ionic solids, the electrostatic interactions between nanoscale clusters could be frustrated by using large clusters with long and flexible side-chains so that the ionic cluster pairs do not crystallize. As such, we report ionic superatomic materials that can be easily solution-processed into completely amorphous and homogeneous thin-films. These new amorphous superatomic materials show tunable compositions and new properties that are not achievable in crystals, including very high electrical conductivities of up to 300 S per meter, ultra low thermal conductivities of 0.05 W per meter per degree kelvin, and high optical transparency of up to 92%. We also demonstrate thin-film thermoelectrics with unoptimized ZT values of 0.02 based on the superatomic thin-films. Such properties are competitive to state-of-the-art materials and make superatomic materials promising as a new class of electronic and thermoelectric materials for devices.

Observations of a pre-merger shock in colliding clusters of galaxies

Clusters of galaxies are the largest known gravitationally-bound structures in the Universe. When clusters collide, they create merger shocks on cosmological scales, which transform most of the kinetic energy carried by the cluster gaseous halos into heat. Observations of merger shocks provide key information of the merger dynamics, and enable insights into the formation and thermal history of the large-scale structures. Nearly all of the merger shocks are found in systems where the clusters have already collided, knowledge of shocks in the pre-merger phase is a crucial missing ingredient. Here we report on the discovery of a unique shock in a cluster pair 1E 2216 and 1E 2215. The two clusters are observed at an early phase of major merger. Contrary to all the known merger shocks observed ubiquitously on merger axes, the new shock propagates outward along the equatorial plane of the merger. This discovery uncovers an important epoch in the formation of massive clusters, when the rapid approach of the cluster pair leads to strong compression of gas along the merger axis. Current theoretical models predict that the bulk of the shock energy might be dissipated outside the clusters, and eventually turn into heat of the pristine gas in the circum-cluster space.

Birds invest wingbeats to keep a steady head and reap the ultimate benefits of flying together.

Flapping flight is the most energetically demanding form of sustained forwards locomotion that vertebrates perform. Flock dynamics therefore have significant implications for energy expenditure. Despite this, no studies have quantified the biomechanical consequences of flying in a cluster flock or pair relative to flying solo. Here, we compared the flight characteristics of homing pigeons (Columba livia) flying solo and in pairs released from a site 7 km from home, using high-precision 5 Hz global positioning system (GPS) and 200 Hz tri-axial accelerometer bio-loggers. As expected, paired individuals benefitted from improved homing route accuracy, which reduced flight distance by 7% and time by 9%. However, realising these navigational gains involved substantial changes in flight kinematics and energetics. Both individuals in a pair increased their wingbeat frequency by 18% by decreasing the duration of their upstroke. This sharp increase in wingbeat frequency caused just a 3% increase in airspeed but reduced the oscillatory displacement of the body by 22%, which we hypothesise relates to an increased requirement for visual stability and manoeuvrability when flying in a flock or pair. The combination of the increase in airspeed and a higher wingbeat frequency would result in a minimum 2.2% increase in the total aerodynamic power requirements if the wingbeats were fully optimised. Overall, the enhanced navigational performance will offset any additional energetic costs as long as the metabolic power requirements are not increased above 9%. Our results demonstrate that the increases in wingbeat frequency when flying together have previously been underestimated by an order of magnitude and force reinterpretation of their mechanistic origin. We show that, for pigeons flying in pairs, two heads are better than one but keeping a steady head necessitates energetically costly kinematics.

Coherence-based time series clustering for statistical inference and visualization of brain connectivity

We develop the hierarchical cluster coherence (HCC) method for brain signals, a procedure for characterizing connectivity in a network by clustering nodes or groups of channels that display a high level of coordination as measured by “cluster-coherence.” While the most common approach to measure dependence between clusters is through pairs of single time series, our method proposes cluster coherence which measures dependence between pairs of whole clusters rather than between single elements. Thus it takes into account both the dependence between clusters and within channels in a cluster. The identified clusters contain time series that exhibit high cross-dependence in the spectral domain. Simulation studies demonstrate that the proposed HCC method is competitive with the other feature-based clustering methods. To study clustering in a network of multichannel electroencephalograms (EEG) during an epileptic seizure, we applied the HCC method and identified connectivity on alpha $(8,12)$ Hertz and beta $(16,30)$ Hertz bands at different phases of the recording: before an epileptic seizure, during the early and middle phases of the seizure episode. To increase the potential impact of HCC in neuroscience, we also developed the HCC-Vis, an R-Shiny app (RStudio), which can be downloaded from https://carolinaeuan.shinyapps.io/hcc-vis/.

Epidemic IncX3 plasmids spreading carbapenemase genes in the United Arab Emirates and worldwide.

PurposePlasmids of the incompatibility group X type 3 (IncX3) were described carrying various carbapenemase genes in carbapenemase-producing Enterobacteriaceae (CPE) worldwide and in the United Arab Emirates (UAE), as well. To understand the driving force behind the emergence of such plasmids in the UAE, the relationship between IncX3 plasmids encountered locally and globally was investigated.MethodsCPE strains isolated in the UAE during 2009–2014 were screened by X3 PCR-based replicon typing. The clonal relationship of CPE carrying IncX3 plasmids was determined by multi-locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). Complete sequence of selected IncX3 plasmids was determined. Phylogenetic relationship between the carbapenemase carrying IncX3 plasmids from the UAE and of those reported worldwide was established by comparing the plasmid backbones.Results10.2% of the 295 CPE tested were identified to carry IncX3 plasmids: 13 Escherichia coli, 13 Klebsiella pneumoniae, two Enterobacter cloacae, one Citrobacter freundii and one Morganella morganii isolate, respectively. Most of them were non-clonal; with small clusters of triplets and pairs of E. coli and K. pneumoniae, and a cluster of five K. pneumoniae ST11 exhibiting >90% similar PFGE patterns, respectively. The 30 isolates harbored either blaNDM-1, blaNDM-4, blaNDM-5, blaNDM-7, blaOXA-181 or blaKPC-2 carbapenemase genes on IncX3 plasmids. Phylogenetic analysis of the backbone region of IncX3 plasmids carrying various beta-lactamase genes from the UAE (n=23) and that of North-America, Europe, Asia and Australia (n=35) revealed three clusters based on the carbapenemase genes carried: plasmids harboring blaOXA-181 and blaNDM-5 formed two distinct groups, whereas backbones of plasmids with blaNDM-1, blaNDM-4 and blaNDM-7 clustered together. Each cluster contained plasmids of diverse geographical origin.ConclusionThe findings suggest that different carbapenemase gene carrying IncX3 plasmids encountered in the UAE do not evolve locally, rather are subtypes of this epidemic plasmid emerging in this country due to international transfer.