Theory of deoplet vaporization in the region of the thermodynamic critical point

Droplet vaporization in region of thermodynamic critical poin

Hamiltonian and physical Hilbert space in polymer quantum mechanics

In this paper, a version of polymer quantum mechanics, which is inspired by loop quantum gravity, is considered and shown to be equivalent, in a precise sense, to the standard, experimentally tested, Schroedinger quantum mechanics. The kinematical cornerstone of our framework is the so called polymer representation of the Heisenberg-Weyl (H-W) algebra, which is the starting point of the construction. The dynamics is constructed as a continuum limit of effective theories characterized by a scale, and requires a renormalization of the inner product. The result is a physical Hilbert space in which the continuum Hamiltonian can be represented and that is unitarily equivalent to the Schroedinger representation of quantum mechanics. As a concrete implementation of our formalism, the simple harmonic oscillator is fully developed.Comment: 19 pages, 2 figures. Comments and references added. Version to be published in CQ

Matching Crop Requirements to Land Characteristics

Examples of matching crop, soil, and season are given; implications for technology transfer in the tropics are mentioned

Metallic impurities in the Cu-fraction of Ni targets prepared from NiCl2 solutions

Introduction Copper-64 is an emerging radionuclide with applications in PET molecular imaging and/or internal therapy and it is typically produced by proton irradiation of isotopically enriched 64Ni electrodeposited on a suitable backing substrate. We recently reported a simple and efficient method for the preparation of nickel targets from electrolytic solutions of nickel chloride and boric acid [1]. Herein we report our recent research work on the analysis of metallic impurities in the copper-fraction of the radiochemical separation process. Material and Methods Nickel targets were prepared and processed as previously reported [1]. Briefly, the bath solution was composed of a mixture of natural NiCl2. 6H2O (135 mg/ml) and H3BO3 (15 mg/ml) and Ni was electrodeposited using a gold disk as cathode and a platinum wire as anode. The plating process was carried out at room temperature using 2 ml of bath solution (pH = 3.7) and a constant current density of 60 mA/cm2 for 1 hour. The unirradiated Ni targets were dissolved in 1–2 ml of concentrated (10M) HCl at 90 oC. After complete dissolution of the Ni layer, water was added to dilute the acid to 6M, and the solution was transferred onto a chromatographic column containing AG 1-X8 resin equilibrated with 6M HCl. The Ni , Co and Cu isotopes were separated by using the well-known chromatography of the chloro-complexes. The sample-fractions containing the Cu isotopes (15 ml, 0.1M HCl) were collected in plastic centrifuge tubes previously soaked in 1M HNO3 and rinsed with Milli-Q water (18 MΩ cm). Impurities of B, Co, Ni, Cu and Zn in these samples were determined by inductively coupled plasma-mass spectroscopy (ICP-MS) at the Department of Geosciences (Laboratory of Isotopic Studies) of the National University. Results and Conclusions The mass of Ni deposited in 1 h was 25.0 ± 1.0 mg (n = 3) and the current efficiency was > 75 % in all cases. The pH of the electrolytic solution tended to decrease along the electrodeposition process (3.71.6). The results of ICP-MS analysis of the Cu-fractions from the cold chromatography separation runs are shown in FIG. 1. We were particularly interested in the boron impurities as H3BO3 is used as buffer for electrodeposition of the Ni targets. Except for the Ni impurities that were deter-mined to be in the range of ppm (mg/l), all other analyzed metallic impurities were found to be in the range of ppb (µg/l), including boron. The Co, Ni, Cu and Zn impurities determined in the Cu-fraction in this work using Ni targets electrode-posited from a NiCl2 acidic solution, are in the same order of magnitude compared with that obtained when using targets prepared from an alkaline solution [2], with the advantage of the simplicity of the electrodeposition method from NiCl2 solutions, as the target material is already recovered in the chemical form of NiCl2, enabling a simpler, one step process to prepare a new plating solution when using enriched 64Ni target material for the production of 64Cu

Ca II 8542 \AA\ brightenings induced by a solar microflare

We study small-scale brightenings in Ca II 8542 \AA\ line-core images to determine their nature and effect on localized heating and mass transfer in active regions. High-resolution 2D spectroscopic observations of an active region in the Ca II 8542 \AA\ line were acquired with the GFPI attached to the 1.5-meter GREGOR telescope. Inversions of the spectra were carried out using NICOLE. We identified three brightenings of sizes up to 2"x2". We found evidence that the brightenings belonged to the footpoints of a microflare (MF). The properties of the observed brightenings disqualified the scenarios of Ellerman bombs or IRIS bombs. However, this MF shared some common properties with flaring active-region fibrils or flaring arch filaments (FAFs): (1) FAFs and MFs are both apparent in chromospheric and coronal layers according to the AIA channels, and (2) both show flaring arches with lifetimes of about 3.0-3.5 min and lengths of about 20". The inversions revealed heating by 600 K at the footpoint location in the ambient chromosphere during the impulsive phase. Connecting the footpoints, a dark filamentary structure appeared in the Ca II line-core images. Before the start of the MF, the spectra of this structure already indicated average blueshifts, meaning upward motions of the plasma along the LOS. During the impulsive phase, these velocities increased up to -2.2 km/s. Downflows dominated at the footpoints. However, in the upper photosphere, slight upflows occurred during the impulsive phase. Hence, bidirectional flows are present in the footpoints of the MF. Conclusions: We detected Ca II brightenings that coincided with the footpoint location of an MF. The MF event led to a rise of plasma in the upper photosphere, both before and during the impulsive phase. Excess mass, previously raised to at most chromospheric layers, slowly drained downward along arches toward the footpoints of the MF.Comment: Accepted for publication in Astronomy & Astrophysics, 13 pages, 6 figures, 1 online movi

Rapid and MR-Independent IK1 activation by aldosterone during ischemia-reperfusion

In ST elevation myocardial infarction (STEMI) context, clinical studies have shown the deleterious effect of high aldosterone levels on ventricular arrhythmia occurrence and cardiac mortality. Previous in vitro reports showed that during ischemia-reperfusion, aldosterone modulates K+ currents involved in the holding of the resting membrane potential (RMP). The aim of this study was to assess the electrophysiological impact of aldosterone on IK1 current during myocardial ischemia-reperfusion. We used an in vitro model of “border zone” using right rabbit ventricle and standard microelectrode technique followed by cell-attached recordings from freshly isolated rabbit ventricular cardiomyocytes. In microelectrode experiments, aldosterone (10 and 100 nmol/L, n=7 respectively) increased the action potential duration (APD) dispersion at 90% between ischemic and normoxic zones (from 95±4ms to 116±6 ms and 127±5 ms respectively, P<0.05) and reperfusion-induced sustained premature ventricular contractions occurrence (from 2/12 to 5/7 preparations, P<0.05). Conversely, potassium canrenoate 100 nmol/L and RU 28318 1 μmol/l alone did not affect AP parameters and premature ventricular contractions occurrence (except Vmax which was decreased by potassium canrenoate during simulated-ischemia). Furthermore, aldosterone induced a RMP hyperpolarization, evoking an implication of a K+ current involved in the holding of the RMP. Cell-attached recordings showed that aldosterone 10 nmol/L quickly activated (within 6.2±0.4 min) a 30 pS K+-selective current, inward rectifier, with pharmacological and biophysical properties consistent with the IK1 current (NPo =1.9±0.4 in control vs NPo=3.0±0.4, n=10, P<0.05). These deleterious effects persisted in presence of RU 28318, a specific MR antagonist, and were successfully prevented by potassium canrenoate, a non specific MR antagonist, in both microelectrode and patch-clamp recordings, thus indicating a MR-independent IK1 activation. In this ischemia-reperfusion context, aldosterone induced rapid and MR-independent deleterious effects including an arrhythmia substrate (increased APD90 dispersion) and triggered activities (increased premature ventricular contractions occurrence on reperfusion) possibly related to direct IK1 activation

Fractal space-times under the microscope: A Renormalization Group view on Monte Carlo data

The emergence of fractal features in the microscopic structure of space-time is a common theme in many approaches to quantum gravity. In this work we carry out a detailed renormalization group study of the spectral dimension $d_s$ and walk dimension $d_w$ associated with the effective space-times of asymptotically safe Quantum Einstein Gravity (QEG). We discover three scaling regimes where these generalized dimensions are approximately constant for an extended range of length scales: a classical regime where $d_s = d, d_w = 2$, a semi-classical regime where $d_s = 2d/(2+d), d_w = 2+d$, and the UV-fixed point regime where $d_s = d/2, d_w = 4$. On the length scales covered by three-dimensional Monte Carlo simulations, the resulting spectral dimension is shown to be in very good agreement with the data. This comparison also provides a natural explanation for the apparent puzzle between the short distance behavior of the spectral dimension reported from Causal Dynamical Triangulations (CDT), Euclidean Dynamical Triangulations (EDT), and Asymptotic Safety.Comment: 26 pages, 6 figure