Polarization entanglement visibility of photon pairs emitted by a quantum dot embedded in a microcavity

We study the photon emission from a quantum dot embedded in a microcavity. Incoherent pumping of its excitons and biexciton provokes the emission of leaky and cavity modes. By solving a master equation we obtain the correlation functions required to compute the spectrum and the relative efficiency among the emission of pairs and single photons. A quantum regime appears for low pumping and large rate of emission. By means of a post-selection process, a two beams experiment with different linear polarizations could be performed producing a large polarization entanglement visibility precisely in the quantum regime.Comment: 13 pages and 6 figure

Optimizing CIGB-300 intralesional delivery in locally advanced cervical cancer

Background:We conducted a phase 1 trial in patients with locally advanced cervical cancer by injecting 0.5 ml of the CK2-antagonist CIGB-300 in two different sites on tumours to assess tumour uptake, safety, pharmacodynamic activity and identify the recommended dose.Methods:Fourteen patients were treated with intralesional injections containing 35 or 70 mg of CIGB-300 in three alternate cycles of three consecutive days each before standard chemoradiotherapy. Tumour uptake was determined using 99 Tc-radiolabelled peptide. In situ B23/nucleophosmin was determined by immunohistochemistry.Results:Maximum tumour uptake for CIGB-300 70-mg dose was significantly higher than the one observed for 35 mg: 16.1±8.9 vs 31.3±12.9 mg (P=0.01). Both, AUC 24h and biological half-life were also significantly higher using 70 mg of CIGB-300 (P<0.001). Unincorporated CIGB-300 diffused rapidly to blood and was mainly distributed towards kidneys, and marginally in liver, lungs, heart and spleen. There was no DLT and moderate allergic-like reactions were the most common systemic side effect with strong correlation between unincorporated CIGB-300 and histamine levels in blood. CIGB-300, 70 mg, downregulated B23/nucleophosmin (P=0.03) in tumour specimens.Conclusion:Intralesional injections of 70 mg CIGB-300 in two sites (0.5 ml per injection) and this treatment plan are recommended to be evaluated in phase 2 studies.Fil: Sarduy, M. R.. Medical-surgical Research Center; CubaFil: García, I.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Coca, M. A.. Clinical Investigation Center; CubaFil: Perera, A.. Clinical Investigation Center; CubaFil: Torres, L. A.. Clinical Investigation Center; CubaFil: Valenzuela, C. M.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Baladrón, I.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Solares, M.. Hospital Materno Ramón González Coro; CubaFil: Reyes, V.. Center For Genetic Engineering And Biotechnology Havana; CubaFil: Hernández, I.. Isotope Center; CubaFil: Perera, Y.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Martínez, Y. M.. Medical-surgical Research Center; CubaFil: Molina, L.. Medical-surgical Research Center; CubaFil: González, Y. M.. Medical-surgical Research Center; CubaFil: Ancízar, J. A.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Prats, A.. Clinical Investigation Center; CubaFil: González, L.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Casacó, C. A.. Clinical Investigation Center; CubaFil: Acevedo, B. E.. Centro de Ingeniería Genética y Biotecnología; CubaFil: López Saura, P. A.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes; ArgentinaFil: Gómez, R.. Elea Laboratories; ArgentinaFil: Perea Rodríguez, S. E.. Center For Genetic Engineering And Biotechnology Havana; Cuba. Centro de Ingeniería Genética y Biotecnología; Cub

Spitzer/IRS spectroscopy of high mass precursors to planetary nebulae

We present Spitzer/IRS observations of a small sample of heavily obscured IRAS sources displaying both the infrared and OH maser emission characteristic of OH/IR stars on the asymptotic giant branch (AGB), but also radio continuum emission typical of ionized planetary nebulae (PNe), the so-called OHPNe. Our observations show that their mid-infrared spectra are dominated by the simultaneous presence of strong and broad amorphous silicate absorption features together with crystalline silicate features, originated in their O-rich circumstellar shells. Out of the five sources observed, three of them are clearly non-variable at infrared wavelengths, confirming their post-AGB status, while the remaining two still show strong photometric fluctuations, and may still have not yet departed from the AGB. One of the non-variable sources in the sample, IRAS 17393-2727, displays a strong [Ne II] nebular emission at 12.8 microns, indicating that the ionization of its central region has already started. This suggests a rapid evolution from the AGB to the PN stage. We propose that these heavily obscured OHPNe represent the population of high mass precursors to PNe in our Galaxy.Comment: To appear in The Astrophysical Journal Letters (scheduled in the 2007 September 1 issue

The night-sky at the Calar Alto Observatory II: The sky at the near infrared

We present here the characterization of the night sky-brightness at the near-infrared, the telescope seeing, and the fraction of useful time at the Calar Alto observatory. For this study we have collected a large dataset comprising 7311 near-infrared images taken regularly along the last four years for the ALHAMBRA survey (J, H and Ks-bands), together with a more reduced dataset of additional near-infrared images taken for the current study. In addition we collected the information derived by the meteorological station at the observatory during the last 10 years, together with the results from the cloud sensor for the last ~2 years. We analyze the dependency of the near-infrared night sky-brightness with the airmass and the seasons, studying its origins and proposing a zenithal correction. A strong correlation is found between the night sky-brightness in the Ks-band and the air temperature, with a gradient of ~ -0.08 mag per 1 C degree. The typical (darkest) night sky-brightness in the J, H and Ks-band are 15.95 mag (16.95 mag), 13.99 mag (14.98 mag) and 12.39 mag (13.55 mag), respectively. These values show that Calar Alto is as dark in the near-infrared as most of the other astronomical astronomical sites in the world that we could compare with. Only Mauna Kea is clearly darker in the Ks-band. The typical telescope seeing at the 3.5m is ~1.0" when converted to the V-band, being only slightly larger than the atmospheric seeing measured at the same time by the seeing monitor, ~0.9". Finally we estimate the fraction of useful time based on the relative humidity, gust wind speed and presence of clouds. This fraction, ~72%, is very similar to the one derived in Paper I, based on the fraction of time when the extinction monitor is working.Comment: 15 pages, 6 figures, accepted to be published in PAS

Insulin Resistance and Gray Matter Volume in Neurodegenerative Disease

The goal of this study was to compare insulin resistance in aging and aging-related neurodegenerative diseases, and to determine the relationship between insulin resistance and gray matter volume (GMV) in each cohort using an unbiased, voxel-based approach. Insulin resistance was estimated in apparently healthy elderly control (HC, n = 21) and neurodegenerative disease (Alzheimer’s disease (AD), n = 20; Parkinson’s disease (PD), n = 22) groups using Homeostasis Model Assessment of Insulin Resistance 2 (HOMA2) and intravenous glucose tolerance test (IVGTT). HOMA2 and GMV were assessed within groups through General Linear Model multiple regression. We found that HOMA2 was increased in both AD and PD compared to the HC group (HC vs. AD, p = 0.002, HC vs. PD, p = 0.003), although only AD subjects exhibited increased fasting glucose (p = 0.005). Furthermore, our voxel-based morphometry analysis revealed that HOMA2 was related to GMV in all cohorts in a region-specific manner (p < 0.001, uncorrected). Significant relationships were observed in the medial prefrontal cortex (HC), medial temporal regions (AD), and parietal regions (PD). Finally, the directionality of the relationship between HOMA2 and GMV was disease-specific. Both HC and AD subjects exhibited negative relationships between HOMA2 and brain volume (increased HOMA2 associated with decreased brain volume), while a positive relationship was observed in PD. This cross-sectional study suggests that insulin resistance is increased in neurodegenerative disease, and that individuals with AD appear to have more severe metabolic dysfunction than individuals with PD or PD dementia

Spitzer Infrared Spectrograph Observations of Magellanic Cloud Planetary Nebulae: the nature of dust in low metallicity circumstellar ejecta

We present 5 - 40 micron spectroscopy of 41 planetary nebulae (PNe) in the Magellanic Clouds, observed with the Infrared Spectrograph on board the Spitzer Space Telescope. The spectra show the presence of a combination of nebular emission lines and solid-state features from dust, superimposed on the thermal IR continuum. By analyzing the 25 LMC and 16 SMC PNe in our sample we found that the IR spectra of 14 LMC and 4 SMC PNe are dominated by nebular emission lines, while the other spectra show solid-state features. We observed that the solid-state features are compatible with carbon-rich dust grains (SiC, polycyclic aromatic hydrocarbons (PAHs), etc.) in most cases, except in three PNe showing oxygen-rich dust features. The frequency of carbonaceous dust features is generally higher in LMC than in SMC PNe. The spectral analysis allowed the correlations of the dust characteristics with the gas composition and morphology, and the properties of the central stars. We found that: 1) all PNe with carbonaceous dust features have C/O>1, none of these being bipolar or otherwise highly asymmetric; 2) all PNe with oxygen-rich dust features have C/O<1, with probable high mass progenitors if derived from single-star evolution (these PNe are either bipolar or highly asymmetric); 3) the dust temperature tracks the nebular and stellar evolution; and 4) the dust production efficiency depends on metallicity, with low metallicity environments not favoring dust production.Comment: The Astrophysical Journal, in pres

Supply-chain modelling and control under proportional inventory-replenishment policies

A novel state-space model of a multi-node supply chain is presented, controlled via local proportional inventory-replenishment policies. The model is driven by a stochastic sequence representing customer demand. The model is analysed under stationarity conditions and a simple recursive scheme is developed for updating its covariance matrix. This allows us to characterise the ‘bullwhip effect’ (demand amplification) in the chain and to solve an optimisation problem for a three-node model involving the minimisation of inventory subject to a probabilistic constraint on downstream demand. Finally, issues related to estimation schemes based on local historical data are briefly discussed

New groups of planetary nebulae with peculiar dust chemistry towards the Galactic bulge

We investigate Galactic bulge planetary nebulae without emission-line central stars for which peculiar infrared spectra have been obtained with the Spitzer Space Telescope, including the simultaneous signs of oxygen and carbon based dust. Three separate sub-groups can be defined characterized by the different chemical composition of the dust and the presence of crystalline and amorphous silicates. We find that the classification based on the dust properties is reflected in the more general properties of these planetary nebulae. However, some observed properties are difficult to relate to the common view of planetary nebulae. In particular, it is challenging to interpret the peculiar gas chemical composition of many analyzed objects in the standard picture of the evolution of planetary nebulae progenitors. We confirm that the dual-dust chemistry phenomenon is not limited to planetary nebulae with emission-line central stars.Comment: 17 pages, 13 figure