Bichromatic dressing of a quantum dot detected by a remote second quantum dot

We demonstrate an information transfer mechanism between two dissimilar remote InAs/GaAs quantum dots weakly coupled to a common photonic crystal microcavity. Bichromatic excitation in the s state of one of the dots leads to the formation of dressed states due to the coherent coupling to the laser field, in resonance with the quantum dot. Information on the resulting dressed structure is read out through the photoluminescence spectrum of the other quantum dot, as well as the cavity mode. The effect is also observed upon exchange of the excitation and detection quantum dots. This quantum dot intertalk is interpreted in terms of a cavity-mediated coupling involving acoustic phonons. A master equation for a three-level system coherently pumped by the two lasers quantitatively describes the behavior of our system. Our result presents an important step towards scalable solid-state quantum networking based on coupled multi-quantum-dot-cavity systems, without the need to use identical quantum emittersThis work was supported by the Spanish MINECO under Contract No. MAT2011-22997, by CAM under Contract No. S2009/ESP-1503, and by the FP7 ITN Spin-optronics (237252). C.S-M. and E.C. acknowledge FPI gran

Effects of formalin fixation on polarimetric properties of brain tissue: fresh or fixed?

Imaging Mueller polarimetry (IMP) appears as a promising technique for real-time delineation of healthy and neoplastic tissue during neurosurgery. The training of machine learning algorithms used for the image post-processing requires large data sets typically derived from the measurements of formalin-fixed brain sections. However, the success of the transfer of such algorithms from fixed to fresh brain tissue depends on the degree of alterations of polarimetric properties induced by formalin fixation (FF). Comprehensive studies were performed on the FF induced changes in fresh pig brain tissue polarimetric properties. Polarimetric properties of pig brain were assessed in 30 coronal thick sections before and after FF using a wide-field IMP system. The width of the uncertainty region between gray and white matter was also estimated. The depolarization increased by 5% in gray matter and remained constant in white matter following FF, whereas the linear retardance decreased by 27% in gray matter and by 28% in white matter after FF. The visual contrast between gray and white matter and fiber tracking remained preserved after FF. Tissue shrinkage induced by FF did not have a significant effect on the uncertainty region width. Similar polarimetric properties were observed in both fresh and fixed brain tissues, indicating a high potential for transfer learning

No Budge for any Nudge: Information Provision and Higher Education Application Outcomes

Peer reviewed: TrueFunder: Network for East Anglian Collaborative Outreach (neaco)Despite increasing efforts to improve their access, students facing socio-economic disadvantages are still underrepresented in UK higher education. In this paper, we study whether behavioural nudging with information provision through text messages, embedded within a larger programme of widening participation activities, can be effective at increasing higher education application rates. We conducted two randomised control trials in which final year students in schools and further education colleges in areas with low higher education participation rates in the East of England region received a series of text messages that prompted thinking and/or action regarding the process of applying to higher education. We find null and statistically insignificant effects on application outcomes, suggesting that behavioural nudging in a setting where it is implemented as part of a more intensive widening participation programme is not effective at increasing higher education application rates. These results add to recent evidence regarding the potential impact of nudging in education by studying such interventions within a busy intervention space.</jats:p

Airborne microbial concentrations and PM10 levels in air conditioned offices

Μη διαθέσιμη περίληψηNot available summarizationΠαρουσιάστηκε στο: European Aerosol Conferenc

Spontaneous nonground state polariton condensation in pillar microcavities

We observe spontaneously driven nonground state polariton condensation in GaAs pillar microcavities under nonresonant optical excitation. We identify a regime where the interplay of exciton-exciton and pair polariton scattering can lead to mode switching from nonground state to ground state polariton condensation. A simple kinematic model satisfactorily describes the observed mode switching as each of the above scattering mechanisms becomes prevalent at different carrier densities.<br/

Controlling the properties of single photon emitters via the Purcell effect

Single photon emission by an InAs/GaAs quantum dot weakly coupled to a photonic crystal microcavity has been studied as a function of energy detuning. Precise and continuous control of the photon statistics as well as of the linear polarization emission angle is achieved simply by changing the energy detuning between the exciton and the cavity mode. A continuous decrease of the antibunching time, the bunching amplitude and the g2(0) value is observed as the detuning is decreased at constant excitation rate, due to the detuning-dependent Purcell effect. © 2012 American Physical Society.This work has been supported by the Spanish Ministry of Education Grants Naninpho-QD TEC2008-06756-C03-01, MAT2011-22997, the Community of Madrid Grant CAM (S2009/ESP-1503), and the FP7 ITN Spin-optronics (237252).Peer Reviewe

Integrated longitudinal analysis of adult grade 4 diffuse gliomas with long-term relapse interval revealed upregulation of TGF-β signaling in recurrent tumors.

Adult-type diffuse gliomas, CNS WHO grade 4 are the most aggressive primary brain tumors and represent a particular challenge of therapeutic intervention. In a single-center retrospective study of matched pairs of initial and post-therapeutic glioma cases with a recurrence period greater than one year, we performed whole exome sequencing combined with mRNA and microRNA expression profiling to identify processes that are altered in recurrent gliomas. Mutational analysis of recurrent gliomas revealed early branching evolution in seventy-five percent of patients. High plasticity was confirmed at the mRNA and miRNA levels. SBS1 signature was reduced and SBS11 was elevated, demonstrating the effect of alkylating agent therapy on the mutational landscape. There was no evidence for secondary genomic alterations driving therapy resistance. ALK7/ACVR1C and LTBP1 were upregulated, whereas LEFTY2 was downregulated, pointing towards enhanced Tumor Growth Factor β (TGF-β) signaling in recurrent gliomas. Consistently, altered microRNA expression profiles pointed towards enhanced Nuclear Factor Kappa B and Wnt signaling that, cooperatively with TGF-β, induces epithelial to mesenchymal transition (EMT), migration and stemness. TGF-β-induced expression of pro-apoptotic proteins and repression of anti-apoptotic proteins were uncoupled in the recurrent tumor. Our results suggest an important role of TGF-β signaling in recurrent gliomas. This may have clinical implication, since TGF-β inhibitors have entered clinical phase studies and may potentially be used in combination therapy to interfere with chemoradiation resistance. Recurrent gliomas show high incidence of early branching evolution. High tumor plasticity is confirmed at the level of microRNA and mRNA expression profiles