Recurrence of biased quantum walks on a line

The Polya number of a classical random walk on a regular lattice is known to depend solely on the dimension of the lattice. For one and two dimensions it equals one, meaning unit probability to return to the origin. This result is extremely sensitive to the directional symmetry, any deviation from the equal probability to travel in each direction results in a change of the character of the walk from recurrent to transient. Applying our definition of the Polya number to quantum walks on a line we show that the recurrence character of quantum walks is more stable against bias. We determine the range of parameters for which biased quantum walks remain recurrent. We find that there exist genuine biased quantum walks which are recurrent.Comment: Journal reference added, minor corrections in the tex

Effect of doping on the dielectric properties of cerium oxide in the microwave and far-infrared frequency range

Cerium oxide (CeO2) has been prepared as a ceramic dielectric resonator by a conventional solid-state ceramic route. The sintered CeO2 has a high dielectric quality factor (Q×f), Q value of 10 000 at 6 GHz with a relative permittivity (ε′) of 23, and temperature coefficient of resonant frequency (τf of -53 ppm/°C. The Q value increases to 20 000 at 6 GHz when the CeO2 is doped with 1 mol% CaCO3. Higher levels of CaCO3 doping lowers the Q and ε′ values and simultaneously decreases τf. TiO2 doping decreases τf and slightly increases ε′, but deceases the Q value. The Q value of pure CeO2 increases to 105 000 at a frequency of 5.58 GHz when it is cooled to 30 K, whereas Q ≈ 85 000 at 5.48 GHz for 1-mol%-CaCO3-doped CeO2 at 30 K

Inflammation of peripheral tissues and injury to peripheral nerves induce diferring effects in the expression of the calcium-sensitive anandamide synthesising enzyme and related molecules in rat primary sensory neuron

Elevation of intracellular Ca 2+ concentration induces the synthesis of N0 arachydonoylethanolamine (anandamide) in a sub0popu lation of primary sensory neurons. N0acylphosphatidylethanolamine phospholipa se D (NAPE0PLD) is the only known enzyme, which synthesises anandamide in a Ca 2+ 0dependent manner. NAPE0 PLD mRNA, as well as anandamide's main targets, the excitatory transient receptor potential vanilloid type 1 ion channel (TRPV1) and the inhibitory cannabinoid type 1 (CB1) receptor and the main anandamide0hydrolysing enzyme fatty acid amide hydrolase (FAAH) are all expressed by sub0populatio ns of nociceptive primary sensory neurons. Thus, NAPE0PLD, TRPV1, the CB1 rec eptor and FAAH could form an autocrine signalling system, which could shape t he activity of a major sub0 population of nociceptive primary sensory neurons, hence contribute to the development of pain. While the expression patterns of TRPV1, the CB1 receptor and FAAH have been comprehensively elucidated, little i s known about NAPE0PLD expression in primary sensory neurons under physiol ogical and pathological conditions. We report that NAPE0PLD is expressed by about a third of primary sensory neurons, the overwhelming majority of which also express nociceptive markers as well as the CB1 receptor, TRPV1 and FAAH . Inflammation of peripheral tissues and injury to peripheral nerves induce diff ering but concerted changes in the expression pattern of NAPE0PLD, the CB1 receptor, T RPV1 and FAAH. Together these data indicate the existence of the anatomical basis for an autocrine signalling system, in a major proportion of nociceptive primar y sensory neurons, and that alterations in that autocrine signalling by periphe ral pathologies could contribute to the development of both inflammatory and neuropathi c pain

Fermilab E791

Fermilab E791, a very high statistics charm particle experiment, recently completed its data taking at Fermilab's Tagged Photon Laboratory. Over 20 billion events were recorded through a loose transverse energy trigger and written to 8mm tape in the the 1991-92 fixed target run at Fermilab. This unprecedented data sample containing charm is being analysed on many-thousand MIP RISC computing farms set up at sites in the collaboration. A glimpse of the data taking and analysis effort is presented. We also show some preliminary results for common charm decay modes. Our present analysis indicates a very rich yield of over 200K reconstructed charm decays.Comment: 4 pages, 1 figure, LaTe

Asymmetries between the production of D+ and D- mesons from 500 GeV/c pi- nucleon interactions as a function of xF and pt**2

We present asymmetries between the production of D+ and D- mesons in Fermilab experiment E791 as a function of xF and pt**2. The data used here consist of 74,000 fully-reconstructed charmed mesons produced by a 500 GeV/c pi- beam on C and Pt foils. The measurements are compared to results of models which predict differences between the production of heavy-quark mesons that have a light quark in common with the beam (leading particles) and those that do not (non-leading particles). While the default models do not agree with our data, we can reach agreement with one of them, PYTHIA, by making a limited number of changes to parameters used

Istodobno spektrofotometrijsko određivanje losartan kalija, amlodipin besilata i hidroklorotiazida u farmaceutskim pripravcima kemometrijskom metodom

In the present work, four different spectrophotometric methods for simultaneous estimation of losartan potassium, amlodipine besilate and hydrochlorothiazide in raw materials and in formulations are described. Overlapped data was quantitatively resolved by using chemometric methods, classical least squares (CLS), multiple linear regression (MLR), principal component regression (PCR) and partial least squares (PLS). Calibrations were constructed using the absorption data matrix corresponding to the concentration data matrix, with measurements in the range of 230.5350.4 nm (∆λ = 0.1 nm) in their zero order spectra. The linearity range was found to be 840, 15 and 315 μg ml1 for losartan potassium, amlodipine besilate and hydrochlorothiazide, respectively. The validity of the proposed methods was successfully assessed for analyses of drugs in the various prepared physical mixtures and in tablet formulations.U radu su opisane četiri spektrofotometrijske metode za istodobno određivanje losartan kalija, amlodipin besilata i hidroklorotiazida u sirovinama i farmaceutskim pripravcima. Podaci koji su se preklapali kvantitativno su razlučeni kemometrijskim metodama, klasičnom metodom najmanjih kvadrata (CLS), multiplom linearnom regresijom (MLR), regresijom glavnih komponenata (PCR) te metodom parcijalnih najmanjih kvadrata (PLS). Kalibracije su provedene koristeći podatke o ovisnosti apsorpcije o koncentracijama, mjereći spektre nultog reda u rasponu 230,5350,4 nm (∆λ = 0,1 nm). Linearnost za losartan kalij bila je 840, za amlodipin besilat 15, a za hidroklorotiazid 315 μg ml1. Valjanost predloženih metoda uspješno je potvrđena analizom navedenih lijekova u različitim pripremljenim smjesama i tabletama

Search for the Flavor-Changing Neutral-Current Decays D+→π+μ+μ−D^+\to \pi^+ \mu^+ \mu^- and D+→π+e+e−D^+\to \pi^+ e^+ e^-

We report the results of a search for the flavor-changing neutral-current decays $D^+\rightarrow \pi^+ \mu^+ \mu^-$ and $D^+\rightarrow \pi^+ e^+ e^-$ in data from Fermilab charm hadroproduction experiment E791. No signal above background is found, and we obtain upper limits on branching fractions, $B(D^+\rightarrow \pi^+ \mu^+ \mu^-) < 1.8 \times 10^{-5}$ and $B(D^+\rightarrow \pi^+ e^+ e^-) < 6.6 \times 10^{-5}$, at the 90\% confidence level.Comment: nine pages with figures; compressed, uuencoded postscrip

Experimental evidence for a light and broad scalar resonance in D+→π−π+π+D^+\to \pi^-\pi^+\pi^+ decay

From a sample of $1172 \pm 61$ $D^+ \to \pi^- \pi^+ \pi^+$ decay, we find $\Gamma (D^+ \to \pi^- \pi^+ \pi^+) / \Gamma (D^+ \to K^- \pi^+ \pi^+) = 0.0311 \pm 0.0018 ^{+0.0016}_{-0.0026}$. Using a coherent amplitude analysis to fit the Dalitz plot of this decays, we find strong evidence that a scalar resonance of mass $478^{+24}_{-23} \pm 17$ MeV/$c^2$ and width $324^{+42}_{-40} \pm 21$ MeV/$c^2$ accounts for approximately half of all decays.Comment: 10 pages, 3 eps figure

Dalitz Plot Analysis of the Decay D^+ --> K^- pi^+ pi^+ and Indication of a Low-Mass Scalar K pi Resonance

We study the Dalitz plot of the decay D^+ --> K^- pi^+ pi^+ with a sample of 15090 events from Fermilab experiment E791. Modeling the decay amplitude as the coherent sum of known K pi resonances and a uniform nonresonant term, we do not obtain an acceptable fit. If we allow the mass and width of the K^*_0(1430) to float, we obtain values consistent with those from PDG but the chi^2 per degree of freedom of the fit is still unsatisfactory. A good fit is found when we allow for the presence of an additional scalar resonance, with mass 797 +/- 19 +/- 43 MeV/c^2 and width 410 +/- 43 +/- 87 MeV/c^2. The mass and width of the K^*_0(1430) become 1459 +/- 7 +/- 5 MeV/c^2 and 175 +/- 12 +/- 12 MeV/c^2, respectively. Our results provide new information on the scalar sector in hadron spectroscopy.Comment: Accepted for publication in Physical Review Letter