Atmospheric Channel Characteristics for Quantum Communication with Continuous Polarization Variables

We investigate the properties of an atmospheric channel for free space quantum communication with continuous polarization variables. In our prepare-and-measure setup, coherent polarization states are transmitted through an atmospheric quantum channel of 100m length on the roof of our institute's building. The signal states are measured by homodyne detection with the help of a local oscillator (LO) which propagates in the same spatial mode as the signal, orthogonally polarized to it. Thus the interference of signal and LO is excellent and atmospheric fluctuations are autocompensated. The LO also acts as spatial and spectral filter, which allows for unrestrained daylight operation. Important characteristics for our system are atmospheric channel influences that could cause polarization, intensity and position excess noise. Therefore we study these influences in detail. Our results indicate that the channel is suitable for our quantum communication system in most weather conditions.Comment: 6 pages, 4 figures, submitted to Applied Physics B following an invitation for the special issue "Selected Papers Presented at the 2009 Spring Meeting of the Quantum Optics and Photonics Section of the German Physical Society

Ezh2 inhibition in Kras-driven lung cancer amplifies inflammation and associated vulnerabilities

Kras-driven non–small-cell lung cancers (NSCLCs) are a leading cause of death with limited therapeutic options. Many NSCLCs exhibit high levels of Ezh2, the enzymatic subunit of polycomb repressive complex 2 (PRC2). We tested Ezh2 inhibitors as single agents or before chemotherapy in mice with orthotopic Kras-driven NSCLC grafts, which homogeneously express Ezh2. These tumors display sensitivity to EZH2 inhibition by GSK126 but also amplify an inflammatory program involving signaling through NF-κB and genes residing in PRC2-regulated chromatin. During this process, tumor cells overcome GSK126 antiproliferative effects. We identified oncogenes that may mediate progression through an in vivo RNAi screen aimed at targets of PRC2/NF-κB. An in vitro compound screening linked GSK126-driven inflammation and therapeutic vulnerability in human cells to regulation of RNA synthesis and proteostasis. Interestingly, GSK126-treated NSCLCs in vivo also showed an enhanced response to a combination of nimesulide and bortezomib. Thus, Ezh2 inhibition may restrict cell proliferation and promote defined adaptive responses. Targeting these responses potentially improves outcomes in Kras-driven NSCLCs

Polarized interacting exciton gas in quantum wells and bulk semiconductors

We develop a theory to calculate exciton binding energies of both two- and three-dimensional spin polarized exciton gases within a mean field approach. Our method allows the analysis of recent experiments showing the importance of the polarization and intensity of the excitation light on the exciton luminescence of GaAs quantum wells. We study the breaking of the spin degeneracy observed at high exciton density $(5 \ \ 10^{10} cm ^2)$. Energy level splitting betwen spin +1 and spin -1 is shown to be due to many-body inter-excitonic exchange while the spin relaxation time is controlled by intra-exciton exchange.Comment: Revtex, 4 figures sent by fax upon request by e-mai

The effectiveness of different explicit vocabulary-teaching strategies on learners’ retention of technical and academic words

The effectiveness of explicit instruction, within the context of strategy development in learners, has been widely accepted for several years. However, the methods used within explicit vocabulary instruction are varied and comparatively few studies have directly compared methods. This study investigates the type of instruction (in a visual or written context) as well as the timing of the activity (before or after the main activity). Seventy Arabic learners of English were tested in a 2*2 design. Results showed a positive effect for pre-teaching vocabulary in a visual condition. We conclude that this pre-emptive multimodal approach heightens the learners’ ability to notice vocabulary items thus providing an effective strategy to increase vocabulary intake

Ionization degree of the electron-hole plasma in semiconductor quantum wells

The degree of ionization of a nondegenerate two-dimensional electron-hole plasma is calculated using the modified law of mass action, which takes into account all bound and unbound states in a screened Coulomb potential. Application of the variable phase method to this potential allows us to treat scattering and bound states on the same footing. Inclusion of the scattering states leads to a strong deviation from the standard law of mass action. A qualitative difference between mid- and wide-gap semiconductors is demonstrated. For wide-gap semiconductors at room temperature, when the bare exciton binding energy is of the order of T, the equilibrium consists of an almost equal mixture of correlated electron-hole pairs and uncorrelated free carriers.Comment: 22 pages, 6 figure

The Dark Energy Survey CCD imager design

The Dark Energy Survey is planning to use a 3 sq. deg. camera that houses a {approx} 0.5m diameter focal plane of 62 2kx4k CCDs. The camera vessel including the optical window cell, focal plate, focal plate mounts, cooling system and thermal controls is described. As part of the development of the mechanical and cooling design, a full scale prototype camera vessel has been constructed and is now being used for multi-CCD readout tests. Results from this prototype camera are described

Extended Human Papillomavirus Genotyping to Predict Progression to High-Grade Cervical Precancer: A Prospective Cohort Study in the Southeastern United States

Background: High-risk human papillomavirus (hrHPV) testing (HPV16; else HPV18/45; else HPV31/33/35/52/58; else HPV39/ is utilized in primary cervical cancer screening, generally along with 51/56/59/68). cytology, to triage abnormalities to colposcopy. Most screening-Results: At enrollment, median participant age was 30.1 years; based hrHPV testing involves pooled detection of any hrHPV or of most (63%) were hrHPV-positive. Over follow-up, 24 participants HPV16/18. Cervical neoplasia progression risks based on extended progressed to CIN2þ (7.0%). CIN2þ IR among hrHPV-positive hrHPV genotyping—particularly non-16/18 hrHPV types—are not participants was 3.4/1,000 person-months. CIN2þ IRs were highest well characterized. HPV genotype-specific incidence of high-grade for HPV16 (8.3), HPV33 (7.8), and HPV58 (4.9). Five-year CIN2þ cervical intraepithelial neoplasia or more severe (CIN2þ) following risk was higher for HPV16 (0.34) compared with HPV18/45 (0.12), an abnormal screening result was examined. HPV31/33/35/52/58 (0.12), and HPV39/51/56/59/68 (0.16) (P ¼ 0.05). Methods: We assessed a US-based prospective, multiracial, Conclusions: Non-16/18 hrHPV types are associated with difclinical cohort of 343 colposcopy patients with normal histology ferential CIN2þ progression rates. HPV16, 33, and 58 exhibited the (n ¼ 226) or CIN1 (n ¼ 117). Baseline cervical samples underwent highest rates over 5 years. HPV risk groups warrant further invesHPV DNA genotyping, and participants were followed up to 5 years. tigation in diverse US populations. Genotype-specific CIN2þ incidence rates (IR) were estimated with Impact: These novel data assessing extended HPV genotyping in accelerated failure time models. Five-year CIN2þ risks were estia diverse clinical cohort can inform future directions to improve mated nonparametrically for hierarchical hrHPV risk groups screening practices in the general population

Open charm and charmonium production at relativistic energies

We calculate open charm and charmonium production in $Au+Au$ reactions at $\sqrt{s}$ = 200 GeV within the hadron-string dynamics (HSD) transport approach employing open charm cross sections from $pN$ and $\pi N$ reactions that are fitted to results from PYTHIA and scaled in magnitude to the available experimental data. Charmonium dissociation with nucleons and formed mesons to open charm ($D+\bar{D}$ pairs) is included dynamically. The 'comover' dissociation cross sections are described by a simple phase-space model including a single free parameter, i.e. an interaction strength $M_0^2$, that is fitted to the $J/\Psi$ suppression data for $Pb+Pb$ collisions at SPS energies. As a novel feature we implement the backward channels for charmonium reproduction by $D \bar{D}$ channels employing detailed balance. From our dynamical calculations we find that the charmonium recreation is comparable to the dissociation by 'comoving' mesons. This leads to the final result that the total $J/\Psi$ suppression at $\sqrt{s}$ = 200 GeV as a function of centrality is slightly less than the suppression seen at SPS energies by the NA50 Collaboration, where the 'comover' dissociation is substantial and the backward channels play no role. Furthermore, even in case that all directly produced $J/\Psi$ mesons dissociate immediately (or are not formed as a mesonic state), a sizeable amount of charmonia is found asymptotically due to the $D+\bar{D} \to J/\Psi$ + meson channels in central collisions of $Au+Au$ at $\sqrt{s}$ = 200 GeV which, however, is lower than the $J/\Psi$ yield expected from binary scaling of $pp$ collisions.Comment: 42 pages, including 14 eps figures, discussions extended and references added, to be published in Phys. Rev.

First Measurement of Z/gamma* Production in Compton Scattering of Quasi-real Photons

We report the first observation of Z/gamma* production in Compton scattering of quasi-real photons. This is a subprocess of the reaction e+e- to e+e-Z/gamma*, where one of the final state electrons is undetected. Approximately 55 pb-1 of data collected in the year 1997 at an e+e- centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been analysed. The Z/gamma* from Compton scattering has been detected in the hadronic decay channel. Within well defined kinematic bounds, we measure the product of cross-section and Z/gamma* branching ratio to hadrons to be (0.9+-0.3+-0.1) pb for events with a hadronic mass larger than 60 GeV, dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60 GeV, dominated by (e)egamma* production, this product is found to be (4.1+-1.6+-0.6) pb. Our results agree with the predictions of two Monte Carlo event generators, grc4f and PYTHIA.Comment: 18 pages, LaTeX, 5 eps figures included, submitted to Physics Letters