1,732 research outputs found
Continuous deformations of the Grover walk preserving localization
The three-state Grover walk on a line exhibits the localization effect
characterized by a non-vanishing probability of the particle to stay at the
origin. We present two continuous deformations of the Grover walk which
preserve its localization nature. The resulting quantum walks differ in the
rate at which they spread through the lattice. The velocities of the left and
right-traveling probability peaks are given by the maximum of the group
velocity. We find the explicit form of peak velocities in dependence on the
coin parameter. Our results show that localization of the quantum walk is not a
singular property of an isolated coin operator but can be found for entire
families of coins
Соотношение путей углеводного синтеза при введении свободных и фосфорилированных сахаров в листья картофеля
Показано, что регуляция путей биосинтеза углеводов может осуществляться через изменение концентрации промежуточных и конечных метаболитов. При этом одним из факторов, регулирующих направленность синтеза углеводов, является активность АДФГ- и УДФГ-пирофосфорилаз. По-видимому, регуляция работы этих ферментов может осуществляться низкомолекулярными метаболитами по принципу обратной связи
Flounder metamorphosis: its regulation by various hormones
The elongation and shortening of the flounder fin rays during its metamorphosis may be parallel to the appearance and resorption of the tadpole tail during amphibian metamorphosis. The dorsal fin rays of the Japanese flounder (Paralichthys olivaceus) elongate during the time when thyroid hormone levels are low and are resorbed during climax of metamorphosis when thyroid levels are elevated. Using an in vitro system for culture of isolated flounder fin rays, we examined how various hormones affect the process of resorption. Both T4 and T3 directly stimulated fin ray shortening, T3 being more potent than T4. Other hormones did not directly affect the resorption process but modified the tissue's response to thyroid hormones. Cortisol enhanced the stimulatory effects of both T4 and T3. On the other hand, estradiol and testosterone were inhibitory. Ovine prolactin (oPRL) also diminished the effect of T3 while ovine growth hormone (oGH) was without effect. Similar observations were observed from the in vivo studies.
Thyroid hormone levels, especially T4, were low during premetamorphosis, increased during prometamorphosis, to peak levels during metamorphic climax, and declined in the juveniles. The changes in whole body concentrations of Cortisol paralleled the changes in thyroid hormone concentrations. On the other hand, whole body estradiol and testosterone concentrations did not show significant change and remained low throughout the larval period. The expression of GH and PRLmRNA, as assessed by in situ hybridization using cDNA for flounder PRL and GH also increased during the metamorphosis. However, the increase in the expression of GH and PRL genes was observed later than the increases in tissue levels of thyroid hormones and Cortisol. At late climax, the flounder larvae have undergone considerable transformation, presumably triggered by both hormones, hence the increase in PRL could hardly be antimetamorphic but may have other physiological implications
Measuring Technology of the Anisotropic Tensile Properties of Woven Fabrics
ArticleTEXTILE RESEARCH JOURNAL. 78(12):1116-1123 (2008)journal articl
X-Ray Observations of the Galactic Center with Suzaku
We report on the diffuse X-ray emissions from the Galactic center (GCDX)
observed with the X-ray Imaging Spectrometer (XIS) on board the Suzaku
satellite. The highly accurate energy calibrations and extremely low background
of the XIS provide many new facts on the GCDX. These are (1) the origin of the
6.7/7.0keV lines is collisional excitation in hot plasma, (2) new SNR and
super-bubble candidates are found, (3) most of the 6.4keV line is fluorescence
by X-rays, and (4) time variability of the 6.4keV line is found from the SgrB2
complex.Comment: 4 pages, 6 figure, proceedings of the XMM-Newton workshop, June 2007,
accepted for publication in A
Anomalous superconductivity and its competition with antiferromagnetism in doped Mott insulators
Proximity to a Mott insulating phase is likely to be an important physical
ingredient of a theory that aims to describe high-temperature superconductivity
in the cuprates. Quantum cluster methods are well suited to describe the Mott
phase. Hence, as a step towards a quantitative theory of the competition
between antiferromagnetism (AFM) and d-wave superconductivity (SC) in the
cuprates, we use Cellular Dynamical Mean Field Theory to compute zero
temperature properties of the two-dimensional square lattice Hubbard model. The
d-wave order parameter is found to scale like the superexchange coupling J for
on-site interaction U comparable to or larger than the bandwidth. The order
parameter also assumes a dome shape as a function of doping while, by contrast,
the gap in the single-particle density of states decreases monotonically with
increasing doping. In the presence of a finite second-neighbor hopping t', the
zero temperature phase diagram displays the electron-hole asymmetric
competition between antiferromagnetism and superconductivity that is observed
experimentally in the cuprates. Adding realistic third-neighbor hopping t''
improves the overall agreement with the experimental phase diagram. Since band
parameters can vary depending on the specific cuprate considered, the
sensitivity of the theoretical phase diagram to band parameters challenges the
commonly held assumption that the doping vs T_{c}/T_{c}^{max} phase diagram of
the cuprates is universal. The calculated ARPES spectrum displays the observed
electron-hole asymmetry. Our calculations reproduce important features of
d-wave superconductivity in the cuprates that would otherwise be considered
anomalous from the point of view of the standard BCS approach.Comment: 13 pages, 7 figure
Effect of pravastatin on survival in patients with advanced hepatocellular carcinoma. A randomized controlled trial
Chemotherapy is not effective for hepatocellular carcinoma (HCC). HMG-CoA redutase inhibitors have cytostatic activity for cancer cells, but their clinical usefulness is unknown. To investigate whether pravastatin, a potent HMG-CoA reductase inhibitor, prolongs survival in patients with advanced HCC, this randomized controlled trial was conducted between February 1990 and February 1998 at Osaka University Hospital. 91 consecutive patients <71 years old (mean age 62) with unresectable HCC were enroled in this study. 8 patients were withdrawn because of progressive liver dysfunction; 83 patients were randomized to standard treatment with or without pravastatin. All patients underwent transcatheter arterial embolization (TAE) followed by oral 5-FU 200 mg−1d for 2 months. Patients were then randomly assigned to control (n = 42) and pravastatin (n = 41) groups. Pravastatin was administered at a daily dose of 40 mg. The effect of pravastatin on tumour growth was assessed by ultrasonography. Primary endpoint was death due to progression of HCC. The duration of pravastatin administration was 16.5 ± 9.8 months (mean ± SD). No patients in either group were lost to follow-up. Median survival was 18 months in the pravastatin group versus 9 months in controls (P = 0.006). The Cox proportional hazards model showed that pravastatin was a significant factor contributing to survival. Pravastatin prolonged the survival of patients with advanced HCC, suggesting its value for adjuvant treatment. © 2001 Cancer Research Campaign http://www.bjcancer.co
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