Microcavity controlled coupling of excitonic qubits

Controlled non-local energy and coherence transfer enables light harvesting in photosynthesis and non-local logical operations in quantum computing. The most relevant mechanism of coherent coupling of distant qubits is coupling via the electromagnetic field. Here, we demonstrate the controlled coherent coupling of spatially separated excitonic qubits via the photon mode of a solid state microresonator. This is revealed by two-dimensional spectroscopy of the sample's coherent response, a sensitive and selective probe of the coherent coupling. The experimental results are quantitatively described by a rigorous theory of the cavity mediated coupling within a cluster of quantum dots excitons. Having demonstrated this mechanism, it can be used in extended coupling channels - sculptured, for instance, in photonic crystal cavities - to enable a long-range, non-local wiring up of individual emitters in solids

A comparison of intrauterine haemopoietic cell transplantation and lentiviral gene transfer for the correction of severe β-thalassaemia in a HbbTh3/+ murine model

Major haemoglobinopathies place tremendous strain on global resources. Intrauterine haemopoietic cell (IUHCT) and gene (IUGT) therapies can potentially reduce perinatal morbidities with greater efficacy than postnatal therapy alone. We performed both procedures in the thalassaemic HbbTh3/+ murine model. Intraperitoneal delivery of coisogenic cells at E13-14 produced dose-dependent chimerism. High-dose adult bone marrow (BM) cells maintained 0.2-3.1% chimerism over ~24 weeks and treated heterozygotes demonstrated higher chimerism than wild-type pups (1.6 vs. 0.7%). Fetal liver cells produced higher chimerism compared to adult BM when transplanted at the same doses, maintaining 1.8-2.4% chimerism over ~32 weeks. We boosted transplanted mice postnatally with adult BM cells following busulfan conditioning. Engraftment was maintained at >1% only in recipients which were chimeric prior to boosting. IUHCT-treated non-chimeras and non-IUHCT mice showed micro- or no chimerism. Additional fludarabine treatment produced higher chimerism than busulfan alone. Engraftment was more effective following higher starting chimerism prior to boosting and in heterozygotes. Chimeric heterozygotes expressed 2.2-15.1% donor cells with eventual decline at 24 weeks (vs. <1% in non-chimeras) and demonstrated improved haematological indices and smaller spleens compared to untreated heterozygotes. Intravenous delivery of GLOBE lentiviral-vector expressing HBB (human β-globin) resulted in vector concentration of 0.001-0.6 copies/cell. Most haematological indices were higher in treated than untreated heterozygotes including haemoglobin and mean corpuscular volume, though still lower than in wild-types. Thus both direct IUGT and IUHCT strategies can be used to achieve haematological improvement but require further dose optimisation. IUHCT will be useful combined with postnatal transplantation to further enhance engraftment

Discrete seasonal hydroclimate reconstructions over northern Vietnam for the past three and a half centuries

We present a 350-year hydroclimatic year (HY) index for northern Vietnam derived from three discrete seasonal reconstructions from tree rings: an index of autumn rainfall from the earlywood widths of Chinese Douglas fir (Pseudotsuga sinensis), the first such record from this species, and two nearby published Palmer Drought Severity Index (PDSI) reconstructions from cypress (Fokienia hodginsii) tree rings for spring and summer, respectively. Autumn rainfall over the study region constitutes only around 9% of the annual total, but its variability is strongly linked to the strength of the atmospheric gradient over Asia during the transition from the boreal summer to winter monsoons. Deficit or surplus of autumn rainfall enhances or mitigates, respectively, the impact of the annual winter dry season on trees growing on porous karst hillsides. The most protracted HY drought (dry across all seasons) occurred at the turn of the twentieth century at a time of relative quiet, but a mid-to-late eighteenth century multi-year HY drought coincided with a period of great societal turmoil across mainland Southeast Asia and the Tay Son Rebellion in northern Vietnam. A mid-nineteenth century uprising accompanied by a smallpox epidemic, crop failure and famine, occurred during the worst autumn drought of the past two and a half centuries but only moderate drought in spring and summer. The “Great Vietnamese Famine” of the mid-twentieth century was dry only in autumn, with a wet spring and an average summer

Modulating gradients in regulatory signals within mesenchymal stem cell seeded hydrogels: a novel strategy to engineer zonal articular cartilage.

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Engineering organs and tissues with the spatial composition and organisation of their native equivalents remains a major challenge. One approach to engineer such spatial complexity is to recapitulate the gradients in regulatory signals that during development and maturation are believed to drive spatial changes in stem cell differentiation. Mesenchymal stem cell (MSC) differentiation is known to be influenced by both soluble factors and mechanical cues present in the local microenvironment. The objective of this study was to engineer a cartilaginous tissue with a native zonal composition by modulating both the oxygen tension and mechanical environment thorough the depth of MSC seeded hydrogels. To this end, constructs were radially confined to half their thickness and subjected to dynamic compression (DC). Confinement reduced oxygen levels in the bottom of the construct and with the application of DC, increased strains across the top of the construct. These spatial changes correlated with increased glycosaminoglycan accumulation in the bottom of constructs, increased collagen accumulation in the top of constructs, and a suppression of hypertrophy and calcification throughout the construct. Matrix accumulation increased for higher hydrogel cell seeding densities; with DC further enhancing both glycosaminoglycan accumulation and construct stiffness. The combination of spatial confinement and DC was also found to increase proteoglycan-4 (lubricin) deposition toward the top surface of these tissues. In conclusion, by modulating the environment through the depth of developing constructs, it is possible to suppress MSC endochondral progression and to engineer tissues with zonal gradients mimicking certain aspects of articular cartilage.Funding was provided by Science Foundation Ireland (President of Ireland Young Researcher Award: 08/Y15/B1336) and the European Research Council (StemRepair – Project number 258463)

CsA can induce DNA double-strand breaks: implications for BMT regimens particularly for individuals with defective DNA repair

Several human disorders mutated in core components of the major DNA double-strand break (DSB) repair pathway, non-homologous end joining (NHEJ), have been described. Cell lines from these patients are characterized by sensitivity to DSB-inducing agents. DNA ligase IV syndrome (LIG4) patients specifically, for unknown reasons, respond particularly badly following treatment for malignancy or BMT. We report the first systematic evaluation of the response of LIG4 syndrome to compounds routinely employed for BMT conditioning. We found human pre-B lymphocytes, a key target population for BMT conditioning, when deficient for DNA ligase IV, unexpectedly exhibit significant sensitivity to CsA the principal prophylaxis for GVHD. Furthermore, we found that CsA treatment alone or in combination with BU and fludarabine resulted in increased levels of DSBs specifically in LIG4 syndrome cells compared to wild-type or Artemis-deficient cells. Our study shows that CsA can induce DSBs and that LIG4 syndrome patient's fail to adequately repair this damage. These DSBs likely arise as a consequence of DNA replication in the presence of CsA. This work has implications for BMT and GVHD management in general and specifically for LIG4 syndrome

Methods for specifying the target difference in a randomised controlled trial : the Difference ELicitation in TriAls (DELTA) systematic review

Peer reviewedPublisher PD

Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Observation of associated near-side and away-side long-range correlations in √sNN=5.02 TeV proton-lead collisions with the ATLAS detector

Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣETPb ranges and particle pT