Splenocytes and Lymphocytes: A Study in The Rat Using The Fluorochrome Acridine Orange

Single cell suspensions of lymphocytes derived from the spleen and thoracic duct of rats were labelled with the fluorochrome acridine orange, proved to be viable by tissue culture, and injected into the left ventricle of isogenic rats. No evidence for recirculation of lymphocytes from blood to thoracic duct lymph within a three hour cycle was obtained. The injected cells whether derived from the spleen or thoracic duct homed only to the tissues of the lymphomyeloid complex

Dynamic phenomena in superconducting oxides by ESR

Dynamic electron spin resonance (ESR) measurements compare the paramagnetic and antiferromagnetic (AF) properties of superconducting oxides in the range 4 K to room temperature, at 8 MHz and 9.36 GHz. Two are derivatives of YBa2Cu30 7: 1: Nd(Nd0.05Ba0.95 )2Cu30 7, Te0 =72 K and II: Y0.2Cao.8Sr2[Cu2(Tlo.5Pb0.5 )]07, Te0 =108 K and two are cases where AF ordering dominates the weak superconductivity: III: Nb01.1\u3e 1. 25 ~Teo~ 10 K and IV: La2Ni04.00, 70 K :::: Teo:::: 40 K. At temperatures 298:::: T:::: 64 K, the ESR absorption by I indicates orthorhombic symmetry. The peaks at Ke =2.06, gb =2.13, and Ka =2.24 are identified with the presence of 5% Nd3+( 41912 ) in the Ba layer because the characteristic Cu2+ impurity hyperfine structure is absent and the ESR signal disappears several degrees below Te. Near Te the ESR absorption is reduced by two orders of magnitude. Proximity effects give rise to interference fringes with period r1 ( T) independent of the field B and the rate of sweep dBzldt. ESR is observed below Te because flux penetrates the superconductor. The temperature dependence of r1 leads to an activation energy for the flux motion E0 (1)/R ~ 16 K and Ea (111)/R ~3 K =Te /4. In the superconducting state a coherent flux expulsion response to a change in B. from 500 mT to zero is observed in times T, = 8 to 10 s. The inverse rate of noise spikes due to flux expulsion, when the samples are cooled through Te in a magnetic field, varies from Tnoise=3.5 s for III to 21 s for IV. The microwave absorption spectra identify three temperature regimes: (i) For 3.5 K \u3c T \u3c T m T* \u3c Teo superconducting behavior was confirmed by the energy loss near zero magnetic field and the kinetics of high-field noise due to flux expulsion. Near g =2.00 ESR absorption is observed for all materials. A broad absorption near 50 to 100 mT at 9.36 GHz has been attributed to AF resonance. (ii) T m T* ~ T ~ Te identifies the range where flux motion gives rise to interference fringes in the ESR absorption. (iii) ESR and AF resonance are observed immediately after warming above Tc

Nonlinear force-free modelling: influence of inaccuracies in the measured magnetic vector

Context: Solar magnetic fields are regularly extrapolated into the corona starting from photospheric magnetic measurements that can suffer from significant uncertainties. Aims: Here we study how inaccuracies introduced into the maps of the photospheric magnetic vector from the inversion of ideal and noisy Stokes parameters influence the extrapolation of nonlinear force-free magnetic fields. Methods: We compute nonlinear force-free magnetic fields based on simulated vector magnetograms, which have been produced by the inversion of Stokes profiles, computed froma 3-D radiation MHD simulation snapshot. These extrapolations are compared with extrapolations starting directly from the field in the MHD simulations, which is our reference. We investigate how line formation and instrumental effects such as noise, limited spatial resolution and the effect of employing a filter instrument influence the resulting magnetic field structure. The comparison is done qualitatively by visual inspection of the magnetic field distribution and quantitatively by different metrics. Results: The reconstructed field is most accurate if ideal Stokes data are inverted and becomes less accurate if instrumental effects and noise are included. The results demonstrate that the non-linear force-free field extrapolation method tested here is relatively insensitive to the effects of noise in measured polarization spectra at levels consistent with present-day instruments. Conclusions heading: Our results show that we can reconstruct the coronal magnetic field as a nonlinear force-free field from realistic photospheric measurements with an accuracy of a few percent, at least in the absence of sunspots.Comment: A&A, accepted, 9 Pages, 4 Figure

Doppler-free Yb Spectroscopy with Fluorescence Spot Technique

We demonstrate a simple technique to measure the resonant frequency of the 398.9 nm 1S0 - 1P1 transition for the different Yb isotopes. The technique, that works by observing and aligning fluorescence spots, has enabled us to measure transition frequencies and isotope shifts with an accuracy of 60 MHz. We provide wavelength measurements for the transition that differ from previously published work. Our technique also allows for the determination of Doppler shifted transition frequencies for photoionisation experiments when the atomic beam and laser beam are not perpendicular and furthermore allows us to determine the average velocity of the atoms along the direction of atomic beam

Filling of the Mott-Hubbard gap in the high temperature photoemission spectrum of (V_0.972Cr_0.028)_2O_3

Photoemission spectra of the paramagnetic insulating (PI) phase of (V_0.972Cr_0.028)_2O_3, taken in ultra high vacuum up to the unusually high temperature (T) of 800 K, reveal a property unique to the Mott-Hubbard (MH) insulator and not observed previously. With increasing T the MH gap is filled by spectral weight transfer, in qualitative agreement with high-T theoretical calculations combining dynamical mean field theory and band theory in the local density approximation.Comment: 4 pages, 4 figure

The Pasadena Aerosol Characterization Observatory (PACO): chemical and physical analysis of the Western Los Angeles basin aerosol

The Pasadena Aerosol Characterization Observatory (PACO) represents the first major aerosol characterization experiment centered in the Western/Central Los Angeles Basin. The sampling site, located on the campus of the California Institute of Technology in Pasadena, was positioned to sample a continuous afternoon influx of transported urban aerosol with a photochemical age of 1–2 h and generally free from major local contributions. Sampling spanned 5 months during the summer of 2009, which were broken into 3 regimes on the basis of distinct meteorological conditions. Regime I was characterized by a series of low pressure systems, resulting in high humidity and rainy periods with clean conditions. Regime II typified early summer meteorology, with significant morning marine layers and warm, sunny afternoons. Regime III was characterized by hot, dry conditions with little marine layer influence. Regardless of regime, organic aerosol (OA) is the most significant constituent of nonrefractory submicron Los Angeles aerosol (42, 43, and 55 % of total submicron mass in regimes I, II, and III, respectively). The overall oxidation state remains relatively constant on timescales of days to weeks (O:C = 0.44 ± 0.08, 0.55 ± 0.05, and 0.48 ± 0.08 during regimes I, II, and III, respectively), with no difference in O:C between morning and afternoon periods. Periods characterized by significant morning marine layer influence followed by photochemically favorable afternoons displayed significantly higher aerosol mass and O:C ratio, suggesting that aqueous processes may be important in the generation of secondary aerosol and oxidized organic aerosol (OOA) in Los Angeles. Online analysis of water soluble organic carbon (WSOC) indicates that water soluble organic mass (WSOM) reaches maxima near 14:00–15:00 local time (LT), but the percentage of AMS organic mass contributed by WSOM remains relatively constant throughout the day. Sulfate and nitrate reside predominantly in accumulation mode aerosol, while afternoon SOA production coincides with the appearance of a distinct fine mode dominated by organics. Particulate NH_4NO_3 and (NH_4)_2SO_4 appear to be NH_3-limited in regimes I and II, but a significant excess of particulate NH_4^+ in the hot, dry regime III suggests less SO_4^(2−) and the presence of either organic amines or NH_4^+-associated organic acids. C-ToF-AMS data were analyzed by Positive Matrix Factorization (PMF), which resolved three factors, corresponding to a hydrocarbon-like OA (HOA), semivolatile OOA (SV-OOA), and low-volatility OOA (LV-OOA). HOA appears to be a periodic plume source, while SV-OOA exhibits a strong diurnal pattern correlating with ozone. Peaks in SV-OOA concentration correspond to peaks in DMA number concentration and the appearance of a fine organic mode. LV-OOA appears to be an aged accumulation mode constituent that may be associated with aqueous-phase processing, correlating strongly with sulfate and representing the dominant background organic component. Periods characterized by high SV-OOA and LV-OOA were analyzed by filter analysis, revealing a complex mixture of species during periods dominated by SV-OOA and LV-OOA, with LV-OOA periods characterized by shorter-chain dicarboxylic acids (higher O:C ratio), as well as appreciable amounts of nitrate- and sulfate-substituted organics. Phthalic acid was ubiquitous in filter samples, suggesting that PAH photochemistry may be an important SOA pathway in Los Angeles. Aerosol composition was related to water uptake characteristics, and it is concluded that hygroscopicity is largely controlled by organic mass fraction (OMF). The hygroscopicity parameter κ averaged 0.31 ± 0.08, approaching 0.5 at low OMF and 0.1 at high OMF, with increasing OMF suppressing hygroscopic growth and increasing critical dry diameter for CCN activation (D_d). An experiment-averaged κ_(org) of 0.14 was calculated, indicating that the highly-oxidized organic fraction of aerosol in Los Angeles is appreciably more hygroscopic than previously reported in urban areas. Finally, PACO will provide context for results forthcoming from the CalNex field campaign, which involved ground sampling in Pasadena during the spring and summer of 2010

Static vs. dynamical mean field theory of Mott antiferromagnets

Studying the antiferromagnetic phase of the Hubbard model by dynamical mean field theory, we observe striking differences with static (Hartree-Fock) mean field: The Slater band is strongly renormalized and spectral weight is transferred to spin-polaron side bands. Already for intermediate values of the interaction $U$ the overall bandwidth is larger than in Hartree-Fock, and the gap is considerably smaller. Such differences survive any renormalization of $U$. Our photoemission experiments for Cr-doped V$_2$O$_3$ show spectra qualitatively well described by dynamical mean field theory.Comment: 6 pages, 5 figures - one figure added and further details about quasiparticle dispersio

Generating continuous variable quantum codewords in the near-field atomic lithography

Recently, D. Gottesman et al. [Phys. Rev. A 64, 012310 (2001)] showed how to encode a qubit into a continuous variable quantum system. This encoding was realized by using non-normalizable quantum codewords, which therefore can only be approximated in any real physical setup. Here we show how a neutral atom, falling through an optical cavity and interacting with a single mode of the intracavity electromagnetic field, can be used to safely encode a qubit into its external degrees of freedom. In fact, the localization induced by a homodyne detection of the cavity field is able to project the near-field atomic motional state into an approximate quantum codeword. The performance of this encoding process is then analyzed by evaluating the intrinsic errors induced in the recovery process by the approximated form of the generated codeword.Comment: 9 pages, 5 figure