Properties of the forward-scattered incoherent radiation through intense precipitation

Incoherent radiation generally results from a first- or multiple-order scattering process; the first-order process is studied here with particular regard to its effects on large-capacity radio channels. It is shown, in fact, that the first-order scattering cannot be taken into account simply as noise because it generates fluctuations and nonlinearities of the channel transfer characteristic. In particular, the amplitude and phase fluctuations, the distortions, and the two-frequency correlation function are evaluated in the simple case of a slab of uniform precipitation parallel to the incoming wavefront with a receiving antenna pointed towards it. Practical formulas are given, evidencing the role of antenna directivity, distance and depth of the slab, and precipitation scattering properties.     

Orbital and site diversity systems in rain environment: Radar-derived results

During the summers of 1981 and 1982, an experiment was carried out in the Po River Valley with the scope of evaluating the statistical performance of diversity systems for earth to satellite links experiencing rain attenuation. The data were collected by anS-band meteorological radar scanning a32deginclined plane having the SIRIO path as its highest radial. Attenuation values directly measured through the satellite beacon at 11.6 GHz were used to "calibrate" the radar on event basis, in order to properly convert reflectivity into specific attenuation. In a previous paper the performance of site diversity (SD) systems was presented for earth terminals spaced from 1 to 20 km. In this paper, the same set of data is processed to simulate orbital diversity (OD) systems, which employ two satellites angularly spaced and one earth terminal. Aperture anglesthetaup to95deghave been considered. The results show that this diversity scheme already has a significant gain withtheta = 30degwhere at 10 dB single link attentuation the gain (as defined by Hodge) is 2.5 dB and it increases steadily asthetaincreases. The comparison between orbital diversity and site diversity performances shows that the site separation is linearly related to the orbital diversity aperture angle for any single link attenuation of the site diversity configuration.     

Sugar‐Based Arylsulfonamide Carboxylates as Selective and Water‐Soluble Matrix Metalloproteinase‐12 Inhibitors

Matrix metalloproteinase‐12 (MMP‐12) can be considered an attractive target to study selective inhibitors useful in the development of new therapies for lung and cardiovascular diseases. In this study, a new series of arylsulfonamide carboxylates, with increased hydrophilicity resulting from conjugation with a β‐N‐acetyl‐d ‐glucosamine moiety, were designed and synthesized as MMP‐12 selective inhibitors. Their inhibitory activity was evaluated on human MMPs by using the fluorimetric assay, and a crystallographic analysis was performed to characterize their binding mode. Among these glycoconjugates, a nanomolar MMP‐12 inhibitor with improved water solubility, compound 3 [(R)‐2‐(N‐(2‐(3‐(2‐acetamido‐2‐deoxy‐β‐d ‐glucopyranosyl)thioureido)ethyl)biphenyl‐4‐ylsulfonamido)‐3‐methylbutanoic acid], was identified.     

1-Min Rain Rate Statistics Predictions From 1-Hour Rain Rate Statistics Measurements

A new method is presented, which allows the recovery of the cumulative distribution function (CDF) of point rain rate with 1-min integration time (P(R)₁) from rain rate CDFs with longer integration time (in this case, 1-hour time average rain rate statistics P(R)₆₀)- The method generates the scaling factors between P(R)₆₀) and P(R)₁) as a function of the probability level and of the site geographical coordinates. From the scaling factors, a scaling law of the form proposed by Chebil and Raman is devised. The method is applicable worldwide and produces predictions far more accurate than the ones provided by general P(R) estimation techniques.     

Self interference by rain scattering in satellite radio links

Scattering by rain at millimetre wavelengths may cause disturbance on the same link which uses the incident wave as an information carrier. A numerical evaluation of this disturbance is performed and its dependence on frequency, rain rate, rain depth and antenna gain is presented.     

Distribution and characterization of the melatonin receptors in the hypothalamus and pituitary gland of three domestic ungulates

With some exceptions, in most of the mammals the pituitary pars tuberalis and the hypothalamic suprachiasmatic nuclei are reportedly the main targets for the pineal hormone melatonin. However, it is not known if the conspicuous diversity in the distribution pattern of melatonin binding sites in these areas depicts differences in reproductive behavior observed in the seasonally breeding species in the temperate zones. We explored the distribution and the characteristics of melatonin binding sites in the hypothalamus and pituitary of three species (bovine, horse, and donkey) different in terms of seasonal reproductive competence. The topographical localization, investigated by in vitro autoradiography, revealed 2-[125I]iodomelatonin binding sites only in the pituitary gland in all three species, primarily in the pars tuberalis (PT), but also in the pars distalis (PD) and pars intermedia (PI). Kinetic, inhibition, and saturation studies, performed by means of in vitro binding, revealed presence of a single class high affinity binding sites. The Kd values, melatonin, and 2-iodomelatonin Ki values were in the low picomolar range. Coincubation with GTP gamma S inhibited 2-[125I]iodomelatonin binding, demonstrating that these putative receptors are linked to a G protein in their signal-transduction pathway. The hypothalamus was devoid of specific binding. In conclusion, the results suggest that in these species, the hypophysis may be a principal target for the melatonin action on the reproductive system.     

Reduction of regional cerebral blood flow by melatonin in young rats

Melatonin (10 ng) was subcutaneously administered to 14-day-old Sprague-Dawley rats. Regional blood flow (rCBF) was measured in 22 anatomically defined structures 20 min later using iodo[14C]antipyrine and quantitative autoradiography. rCBF was markedly reduced in the cerebral areas supplied by circle of Willis and the basilar arteries. Melatonin also significantly decreased blood flow to choroid plexuses. These findings suggest that circulating melatonin may contribute to regulation of cerebral blood flow and brain fluid balance.     

The neuropeptide alpha-MSH has specific receptors on neutrophils and reduces chemotaxis in vitro

The proopiomelanocortin-derived peptide alpha-melanocyte stimulating hormone (alpha-MSH) has potent anti-inflammatory effects in all animal models of inflammation against which it has been tested. Understanding of the mechanism by which this occurs is incomplete, although there is recent evidence for alpha-MSH receptors in murine and human macrophages and for modulation of production of proinflammatory cytokines and related mediators by alpha-MSH. Because of the prominence of neutrophils in early stages of inflammatory reactions where alpha-MSH is effective, we examined human neutrophils for evidence of mRNA for alpha-MSH receptors and for inhibition of neutrophil chemotaxis. There was accumulation of mRNA for melanocortin receptor 1 (MC1) in RT/PCR product from neutrophils stimulated with interferon and LPS. In subsequent studies alpha-MSH inhibited migration of neutrophils from most normal volunteers when the cells were placed in FMLP or IL-8 gradients. The inhibition by alpha-MSH could be traced to alterations in cAMP in neutrophils. The presence of alpha-MSH receptor message in neutrophils is consistent with the established anti-inflammatory effects of the peptide. Direct inhibition of neutrophil chemotaxis likely contributes to the anti-inflammatory activity of alpha-MSH.     

Novel continuum models for coupled shear wall analysis

Replacement beam formulations represent a family of 1D continuum models suitable for approximate analyses of the structural arrangements of buildings. In this paper, an energy equivalence approach is applied to coupled shear walls to develop suitable replacement beam models. Assuming properly compatible coupling fields between walls, a novel three‐field coupled two‐beam approach, therein providing shear and axial deformations, is proposed. The corresponding mathematical formulation provides closed‐form solutions for simple loading cases with homogenous properties. Considering slender coupled shear walls, as typically found in tall buildings, the coupled two beams can be reduced to a two‐field formulation, i.e., a parallel assembly of an extensible Euler–Bernoulli beam and a rotation‐constraining beam. The latter model is solved analytically, and expressions for the tip displacement and base bending moment are presented. A finite element model is then presented and demonstrated to be an efficient tool for static and dynamic analyses. The effects of the axial deformation and degree of coupling on slender coupled shear wall responses are described as being dependent upon two suitable parameters. Various approximate relations are also proposed for design purposes. Finally, the validity of both analytical solutions and the finite element model is confirmed via numerical examples. Copyright © 2015 John Wiley & Sons, Ltd.     

Analysis and Parameterization of Methodologies for the Conversion of Rain-Rate Cumulative Distributions from Various Integration Times to One Minute

The conversion of rain-rate cumulative distributions from any integration time, T, to one minute is a viable option whenever local one-minute data (time series or cumulative distribution functions) are not available for microwave system design. This paper reviews some of the most common rain-rate cumulative-distribution conversion methods. For selected models, it provides a complementary set of coefficients for regional and global application by performing regression to a measurements database. The performance of each model is analyzed, together with its adaptability to various climatic regions. Finally, recommendations with regard to the global applicability of models are given.