Riesz transform characterization of Hardy spaces associated with Schr\"odinger operators with compactly supported potentials

Let L=-\Delta+V be a Schr\"odinger operator on R^d, d\geq 3. We assume that V is a nonnegative, compactly supported potential that belongs to L^p(R^d), for some p>d/2. Let K_t be the semigroup generated by -L. We say that an L^1(R^d)-function f belongs to the Hardy space H_L^1 associated with L if sup_{t>0} |K_t f| belongs to L^1(R^d). We prove that f\in H_L^1 if and only if R_j f \in L^1(R^d) for j=1,...,d, where R_j= \frac{d}{dx_j} L^{-1/2} are the Riesz transforms associated with L.Comment: 6 page

60 GHz indoor propagation studies for wireless communications based on a ray-tracing method

This paper demonstrates a ray-tracing method for modeling indoor propagation channels at 60 GHz. A validation of the ray-tracing model with our in-house measurement is also presented. Based on the validated model, the multipath channel parameter such as root mean square (RMS) delay spread and the fading statistics at millimeter wave frequencies are easily extracted. As such, the proposed ray-tracing method can provide vital information pertaining to the fading condition in a site-specific indoor environment

60 GHz indoor propagation studies for wireless communications based on a ray-tracing method

This paper demonstrates a ray-tracing method for modeling indoor propagation channels at 60 GHz. A validation of the ray-tracing model with our in-house measurement is also presented. Based on the validated model, the multipath channel parameter such as root mean square (RMS) delay spread and the fading statistics at millimeter wave frequencies are easily extracted. As such, the proposed ray-tracing method can provide vital information pertaining to the fading condition in a site-specific indoor environment

Immunoglobulin-A distribution in glomerular disease: Analysis of immunofluorescence localization and pathogenetic significance

Immunoglobulin-A distribution in glomerular disease. Analysis of immunofluorescence localization and pathogenetic significance. Renal biopsies from 470 patients with various glomemlonephropathies were studied for patterns and frequency of glomerular bound IgA. Correlations of IgA with IgG, IgM, C3, and C4 were made. Glomerular deposits of IgA were observed in five of six cases of Henoch-Schoenlein anaphylactoid nephritis (83%), stalk proliferative glomerulonephritis (73%), lupus nephritis (60%), and focal proliferative glomerulonephritis (57 %). In addition, IgA was less frequently observed in diffuse (acute) proliferative (33%), membranoproliferative (42%), membranous (32%), focal sclerosing (25%) crescentic (26%), and chronic glomerulonephritides (23%) as well as malignant arterionephrosclerosis, amyloidosis, and a group of patients with minimal glomerular alteration and no determinable diagnosis (40%). IgA was not specifically associated with IgG or IgM in any one diagnostic category but was often present with both. Deposits containing C3 and C4 most closely paralleled those of IgG and/or IgM. Presence of IgA appeared to correlate with variable degrees of increased glomerular mesangial cellularity in “minimal”, stalk proliferative, and focal-segmental glomerular lesions. The cause and immunopathogenetic significance of mesangial or peripheral glomerular capillary localization of IgA is unknown. Though a number of apparent examples of what has been referred to as IgA-IgG nephropathy were observed in this study, this entity, characterized by mesangial deposits of IgA, IgG, and C3, could not always be specifically identified or differentiated on histopathologic criteria alone from a variety of other glomerulopathies in which variable proportions of IgA, IgG, IgM, C3, and C4 globulins were localized

Bromine measurements in ozone depleted air over the Arctic Ocean

In situ measurements of ozone, photochemically active bromine compounds, and other trace gases over the Arctic Ocean in April 2008 are used to examine the chemistry and geographical extent of ozone depletion in the arctic marine boundary layer (MBL). Data were obtained from the NOAA WP-3D aircraft during the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) study and the NASA DC-8 aircraft during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) study. Fast (1 s) and sensitive (detection limits at the low pptv level) measurements of BrCl and BrO were obtained from three different chemical ionization mass spectrometer (CIMS) instruments, and soluble bromide was measured with a mist chamber. The CIMS instruments also detected Br2. Subsequent laboratory studies showed that HOBr rapidly converts to Br2 on the Teflon instrument inlets. This detected Br2 is identified as active bromine and represents a lower limit of the sum HOBr + Br2. The measured active bromine is shown to likely be HOBr during daytime flights in the arctic. In the MBL over the Arctic Ocean, soluble bromide and active bromine were consistently elevated and ozone was depleted. Ozone depletion and active bromine enhancement were confined to the MBL that was capped by a temperature inversion at 200–500 m altitude. In ozone-depleted air, BrO rarely exceeded 10 pptv and was always substantially lower than soluble bromide that was as high as 40 pptv. BrCl was rarely enhanced above the 2 pptv detection limit, either in the MBL, over Alaska, or in the arctic free troposphere

The Standardized Fish Bioassay Procedure for Detecting and Culturing Actively Toxic Pfiesteria, Used by Two Reference Laboratories for Atlantic and Gulf Coast States

In the absence of purified standards of toxins from Pfiesteria species, appropriately conducted fish bioassays are the gold standard that must be used to detect toxic strains of Pfiesteria slop. from natural estuarine water or sediment samples and to culture actively toxic Pfiesteria. In this article, we describe the standardized steps of our fish bioassay as an abbreviated term for a procedure that includes two sets of trials with fish, following the Henle-Koch postulates modified for toxic rather than infectious agents. This procedure was developed in 1991, and has been refined over more than 12 years of experience in research with toxic Pfiesteria. The steps involve isolating toxic strains of Pfiesteria (or other potentially, as-yet-undetected, toxic Pfiesteria or Pfiesteria-like species) from fish-killing bioassays with natural samples; growing the clones with axenic algal prey; and retesting the isolates in a second set of fish bioassays. The specific environmental conditions used (e.g., temperature, salinity, light, other factors) must remain flexible, given the wide range of conditions from which natural estuarine samples are derived. We present a comparison of information provided for fish culture conditions, reported in international science journals in which such research is routinely published, and we provide information from more than 2,000 fish bioassays with toxic Pfiesteria, along with recommendations for suitable ranges and frequency of monitoring of environmental variables. We present data demonstrating that algal assays, unlike these standardized fish bioassays, should not be used to detect toxic strains of Pfiesteria spp. Finally, we recommend how quality control/assurance can be most rapidly advanced among laboratories engaged in studies that require research-quality isolates of toxic Pfiesteria spp

Temperature dependence of UV absorption cross sections and atmospheric implications of several alkyl iodides

The ultraviolet absorption spectra of a number of alkyl iodides which have been found in the troposphere, CH_3I, C_2H_5I, CH_3CH_2CH_2I, CH_3CHICH_3, CH_2I_2, and CH2_ClI, have been measured over the wavelength range 200–380 nm and at temperatures between 298 and 210 K. The absorption spectra of the monoiodides C_H3I, C_2H_5I, CH_3CH_2CH_2I, and CH_3CHICH_3 are nearly identical in shape and magnitude and consist of single broad bands centered near 260 nm. The addition of a chlorine atom in CH_2ClI shifts its spectrum to longer wavelengths (σ_(max) at 270 nm). The spectrum of CH_2I_2 is further red‐shifted, reaching a maximum of 3.85×10^(−18) cm^2 molecule^(−1) at 288 nm and exhibiting strong absorption in the solar actinic region, λ>290 nm. Atmospheric photolysis rate constants, J values, have been calculated assuming quantum efficiencies of unity for different solar zenith angles as a function of altitude using the newly measured cross sections. Surface photolysis rate constants, calculated from the absorption cross sections measured at 298 K, range from 3×10^(−6) s^(−1) for CH)3I to 5×10^(−3) s^(−1) for CH)2I)2 at a solar zenith angle of 40°