916 research outputs found

    Herschel observations of EXtra-Ordinary Sources: Analysis of the HIFI 1.2 THz Wide Spectral Survey Toward Orion KL II. Chemical Implications

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    We present chemical implications arising from spectral models fit to the Herschel/HIFI spectral survey toward the Orion Kleinmann-Low nebula (Orion KL). We focus our discussion on the eight complex organics detected within the HIFI survey utilizing a novel technique to identify those molecules emitting in the hottest gas. In particular, we find the complex nitrogen bearing species CH3_{3}CN, C2_{2}H3_{3}CN, C2_{2}H5_{5}CN, and NH2_{2}CHO systematically trace hotter gas than the oxygen bearing organics CH3_{3}OH, C2_{2}H5_{5}OH, CH3_{3}OCH3_{3}, and CH3_{3}OCHO, which do not contain nitrogen. If these complex species form predominantly on grain surfaces, this may indicate N-bearing organics are more difficult to remove from grain surfaces than O-bearing species. Another possibility is that hot (Tkin_{\rm kin}\sim300 K) gas phase chemistry naturally produces higher complex cyanide abundances while suppressing the formation of O-bearing complex organics. We compare our derived rotation temperatures and molecular abundances to chemical models, which include gas-phase and grain surface pathways. Abundances for a majority of the detected complex organics can be reproduced over timescales \gtrsim 105^{5} years, with several species being under predicted by less than 3σ\sigma. Derived rotation temperatures for most organics, furthermore, agree reasonably well with the predicted temperatures at peak abundance. We also find that sulfur bearing molecules which also contain oxygen (i.e. SO, SO2_{2}, and OCS) tend to probe the hottest gas toward Orion KL indicating the formation pathways for these species are most efficient at high temperatures.Comment: 31 pages, 6 figures, 1 Table, accepted to the Astrophysical Journa

    The minimum wage in Germany: what brought the state in?

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    A statutory minimum wage has been introduced in Germany, in the face of business opposition but abetted by union support. The political coalition in favour of minimum wage regulation brought together the centre-left and the centre-right with the argument that regulation is needed to prevent disfunctional interaction between low wages and the social security system. Thus the dualization which characterises Germany’s inegalitarian form of coordinated capitalism has provoked a corrective political response. The paper traces the long path to government intervention and assesses why employers were unable, or unwilling, to pre-empt intervention by maintaining the coverage of collective bargaining. It is argued that market liberalization has had a paradoxical effect on employer power: intense domestic as well as international competition has reduced employers’ capacity to act strategically to fend off regulation by the government

    Effects of oxidized lipids (4,5 (E)-epoxy-2(E)-heptenal and 4,5 (E)-epoxy-2 (E) -decenal) and lysine reaction products on zinc and calcium utilization: assays in Caco-2 cells

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    The influence of the presence of brown products from the reaction between two oxidized lipids (4,5 (E)-epoxy-2(E)-heptenal, EH, and 4,5 (E)-epoxy-2 (E)-decenal, ED) and lysine (EH-L and ED-L) on zinc and calcium utilization was studied, and compared with a fructosyl-lysine mixture (F-L). Assays were carried out in Caco-2 cells grown in bicameral chambers. The Zn transported across the cell monolayer was significantly lower in the presence of the EH-L, ED-L and F-L samples, specially with EH-L. Significant decreases in Zn uptake were also observed, with no differences between samples. However, calcium transport was not modified. Thus, the assayed lipid-aminoacid brown products seem to have negative effects on Zn availability, whereas Ca availability appears to be unaffected.Se estudió la influencia de la presencia de productos obtenidos en la reacción de dos lípidos oxidados (4,5(E)-epoxy-2(E)- heptenal, EH, y 4,5(E)-epoxy-2(E)-decenal, ED) con el aminoácido lisina (EH-L y ED-L), sobre la absorción de zinc y calcio, comparándolos frente a una mezcla de fructosil-lisina (F-L). Los ensayos se realizaron con células Caco-2 sembradas en placas bicamerales. La adición de las muestras EH-L, ED-L y F-L al medio de cultivo supuso una reducción significativa en el Zn transportado a través de la monocapa de células, mucho más marcada ante la presencia de EH-L. También se redujo significativamente la captación celular de Zn, sin diferencias entre las distintas muestras ensayadas. Sin embargo, el transporte de Ca no se vio modificado. Por lo tanto, los productos pardos lípido-aminoacídicos ensayados parecen afectar negativamente la disponibilidad del Zn, sin tener efectos notables sobre la del Ca.Peer reviewe

    Differentiation of irradiation and cetuximab induced skin reactions in patients with locally advanced head and neck cancer undergoing radioimmunotherapy: the HICARE protocol (Head and neck cancer: ImmunoChemo and Radiotherapy with Erbitux) – a multicenter phase IV trial

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    BACKGROUND: In order to improve the clinical outcome of patients with locally advanced squamous cell carcinoma of the head and neck (LASCCHN) not being capable to receive platinum-based chemoradiation, radiotherapy can be intensified by addition of cetuximab, a monoclonal antibody that blocks the epidermal growth factor receptor (EGFR). The radioimmunotherapy with cetuximab is a feasible treatment option showing a favourable toxicity profile. The most frequent side effect of radiotherapy is radiation dermatitis, the most common side effect of treatment with cetuximab is acneiform rash. Incidence and severity of these frequent, often overlapping and sometimes limiting skin reactions, however, are not well explored. A clinical and molecular differentiation between radiogenic skin reactions and skin reactions caused by cetuximab which may correlate with outcome, have never been described before. METHODS/DESIGN: The HICARE study is a national, multicenter, prospective phase IV study exploring the different types of skin reactions that occur in patients with LASCCHN undergoing radioimmun(chemo)therapy with the EGFR inhibitor cetuximab. 500 patients with LASCCHN will be enrolled in 40 participating sites in Germany. Primary endpoint is the rate of radiation dermatitis NCI CTCAE grade 3 and 4 (v. 4.02). Radioimmunotherapy will be applied according to SmPC, i.e. cetuximab will be administered as loading dose and then weekly during the radiotherapy. Irradiation will be applied as intensity-modulated radiation therapy (IMRT) or 3D-dimensional radiation therapy. DISCUSSION: The HICARE trial is expected to be one of the largest trials ever conducted in head and neck cancer patients. The goal of the HICARE trial is to differentiate skin reactions caused by radiation from those caused by the monoclonal antibody cetuximab, to evaluate the incidence and severity of these skin reactions and to correlate them with outcome parameters. Besides, the translational research program will help to identify and confirm novel peripheral blood based molecular predictors and surrogates for treatment response and resistance. TRIAL REGISTRATION: Clinical Trial Identifier, NCT01553032 (clinicaltrials.gov) EudraCT number: 2010-019748-3

    Single flux quantum circuits with damping based on dissipative transmission lines

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    We propose and demonstrate the functioning of a special Rapid Single Flux Quantum (RSFQ) circuit with frequency-dependent damping. This damping is achieved by shunting individual Josephson junctions by pieces of open-ended RC transmission lines. Our circuit includes a toggle flip-flop cell, Josephson transmission lines transferring single flux quantum pulses to and from this cell, as well as DC/SFQ and SFQ/DC converters. Due to the desired frequency-dispersion in the RC line shunts which ensures sufficiently low noise at low frequencies, such circuits are well-suited for integrating with the flux/phase Josephson qubit and enable its efficient control.Comment: 6 pages incl. 6 figure

    Spatial organization in cyclic Lotka-Volterra systems

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    We study the evolution of a system of NN interacting species which mimics the dynamics of a cyclic food chain. On a one-dimensional lattice with N<5 species, spatial inhomogeneities develop spontaneously in initially homogeneous systems. The arising spatial patterns form a mosaic of single-species domains with algebraically growing size, (t)tα\ell(t)\sim t^\alpha, where α=3/4\alpha=3/4 (1/2) and 1/3 for N=3 with sequential (parallel) dynamics and N=4, respectively. The domain distribution also exhibits a self-similar spatial structure which is characterized by an additional length scale, L(t)tβ{\cal L}(t)\sim t^\beta, with β=1\beta=1 and 2/3 for N=3 and 4, respectively. For N5N\geq 5, the system quickly reaches a frozen state with non interacting neighboring species. We investigate the time distribution of the number of mutations of a site using scaling arguments as well as an exact solution for N=3. Some possible extensions of the system are analyzed.Comment: 18 pages, 10 figures, revtex, also available from http://arnold.uchicago.edu/~ebn

    Beyond the pseudo-time-dependent approach: chemical models of dense core precursors

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    Context: Chemical models of dense cloud cores often utilize the so-called pseudo-time-dependent approximation, in which the physical conditions are held fixed and uniform as the chemistry occurs. In this approximation, the initial abundances chosen, which are totally atomic in nature except for molecular hydrogen, are artificial. A more detailed approach to the chemistry of dense cold cores should include the physical evolution during their early stages of formation. Aims: Our major goal is to investigate the initial synthesis of molecular ices and gas-phase molecules as cold molecular gas begins to form behind a shock in the diffuse interstellar medium. The abundances calculated as the conditions evolve can then be utilized as reasonable initial conditions for a theory of the chemistry of dense cores. Methods: Hydrodynamic shock-wave simulations of the early stages of cold core formation are used to determine the time-dependent physical conditions for a gas-grain chemical network. We follow the cold post-shock molecular evolution of ices and gas-phase molecules for a range of visual extinction up to AV ~ 3, which increases with time. At higher extinction, self-gravity becomes important. Results: As the newly condensed gas enters its cool post-shock phase, a large amount of CO is produced in the gas. As the CO forms, water ice is produced on grains, while accretion of CO produces CO ice. The production of CO2 ice from CO occurs via several surface mechanisms, while the production of CH4 ice is slowed by gas-phase conversion of C into CO.Comment: 9 pages, 3 figures, 2 table

    Connecting Berry's phase and the pumped charge in a Cooper pair pump

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    The properties of the tunnelling-charging Hamiltonian of a Cooper pair pump are well understood in the regime of weak and intermediate Josephson coupling, i.e. when EJECE_{\mathrm{J}}\lesssim E_{\mathrm{C}}. It is also known that Berry's phase is related to the pumped charge induced by the adiabatical variation of the eigenstates. We show explicitly that pumped charge in Cooper pair pump can be understood as a partial derivative of Berry's phase with respect to the phase difference ϕ\phi across the array. The phase fluctuations always present in real experiments can also be taken into account, although only approximately. Thus the measurement of the pumped current gives reliable, yet indirect, information on Berry's phase. As closing remarks, we give the differential relation between Berry's phase and the pumped charge, and state that the mathematical results are valid for any observable expressible as a partial derivative of the Hamiltonian.Comment: 5 pages, 5 figures, RevTeX, Presentation has been clarifie
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