49 research outputs found
Some economic benefits of a synchronous earth observatory satellite
An analysis was made of the economic benefits which might be derived from reduced forecasting errors made possible by data obtained from a synchronous satellite system which can collect earth observation and meteorological data continuously and on demand. User costs directly associated with achieving benefits are included. In the analysis, benefits were evaluated which might be obtained as a result of improved thunderstorm forecasting, frost warning, and grain harvest forecasting capabilities. The anticipated system capabilities were used to arrive at realistic estimates of system performance on which to base the benefit analysis. Emphasis was placed on the benefits which result from system forecasting accuracies. Benefits from improved thunderstorm forecasts are indicated for the construction, air transportation, and agricultural industries. The effects of improved frost warning capability on the citrus crop are determined. The benefits from improved grain forecasting capability are evaluated in terms of both U.S. benefits resulting from domestic grain distribution and U.S. benefits from international grain distribution
Angular correlation, spin alignment, and systematics of mis-matched 12C + 12C inelastic scattering resonances
Particle gamma-ray angular correlation measurements have been used to study the spin alignment and magnetic-substate population parameters for the 21+ (4.443 MeV) state in 12C, populated in the 12C(12C,12C[02+]) 12C(21+) inelastic scattering reaction in the vicinity of a prominent, narrow peak in the scattering excitation function. The data show a strong alignment of the spin with the orbital angular momentum, and suggest that the cross section peak corresponds to a spin 14+ resonance at Ec.m. = 28.0 MeV. This energy is close to that where a strong peak is also observed in the 01+ + 0 2+ excitation function. A comparison between the data for these two channels lends some support to recent theoretical calculations of resonance behavior for angular-momentum-mismatched channels in 12C + 12C inelastic scattering
Critical dynamics in thin films
Critical dynamics in film geometry is analyzed within the field-theoretical
approach. In particular we consider the case of purely relaxational dynamics
(Model A) and Dirichlet boundary conditions, corresponding to the so-called
ordinary surface universality class on both confining boundaries. The general
scaling properties for the linear response and correlation functions and for
dynamic Casimir forces are discussed. Within the Gaussian approximation we
determine the analytic expressions for the associated universal scaling
functions and study quantitatively in detail their qualitative features as well
as their various limiting behaviors close to the bulk critical point. In
addition we consider the effects of time-dependent fields on the
fluctuation-induced dynamic Casimir force and determine analytically the
corresponding universal scaling functions and their asymptotic behaviors for
two specific instances of instantaneous perturbations. The universal aspects of
nonlinear relaxation from an initially ordered state are also discussed
emphasizing the different crossovers that occur during this evolution. The
model considered is relevant to the critical dynamics of actual uniaxial
ferromagnetic films with symmetry-preserving conditions at the confining
surfaces and for Monte Carlo simulations of spin system with Glauber dynamics
and free boundary conditions.Comment: 64 pages, 21 figure
Genetics of Host Response to Leishmania tropica in Mice – Different Control of Skin Pathology, Chemokine Reaction, and Invasion into Spleen and Liver
Several hundred million people are exposed to the risk of leishmaniasis, a disease caused by intracellular protozoan parasites of several Leishmania species and transmitted by phlebotomine sand flies. In humans, L. tropica causes cutaneous form of leishmaniasis with painful and long-persisting lesions in the site of the insect bite, but the parasites can also penetrate to internal organs. The relationship between the host genes and development of the disease was demonstrated for numerous infectious diseases. However, the search for susceptibility genes in the human population could be a difficult task. In such cases, animal models may help to discover the role of different genes in interactions between the parasite and the host. Unfortunately, the literature contains only a few publications about the use of animals for L. tropica studies. Here, we report an animal model suitable for genetic, pathological and drug studies in L. tropica infection. We show how the host genotype influences different disease symptoms: skin lesions, parasite dissemination to the lymph nodes, spleen and liver, and increase of levels of chemokines CCL2, CCL3 and CCL5 in serum
Effect of functional end groups of silane self-assembled monolayer surfaces on apatite formation, fibronectin adsorption and osteoblast cell function
Bioactive glass (BG) can directly bond to living bone without fibrous tissue encapsulation. Key mechanistic steps of BG\u27s activity are attributed to calcium phosphate formation, surface hydroxylation and fibronectin (FN) adsorption. In the present study, self-assembled monolayers (SAMs) of alkanesilanes with different surface chemistry (OH, NH2 and COOH) were used as a model system to mimic BG\u27s surface activity. Calcium phosphate (Ca-P) was formed on SAMs by immersion in a solution that simulates the electrolyte content of physiological fluids. FN adsorption kinetics and monolayer coverage was determined on SAMs with or without Ca-P coating. The surface roughness was also examined on these substrates before and after FN adsorption. The effects of FN-adsorbed, Ca-P-coated SAMs on the function of MC3T3-E1 were evaluated by cell growth, expression of alkaline phosphatase activity and actin cytoskeleton formation. We demonstrate that, although the FN monolayer coverage and the root mean square (rms) roughness are similar on - OH and - COOH terminated SAMs with or without Ca-P coating, higher levels of ALP activity, more actin cytoskeleton formation and more cell growth are obtained on - OH- and - COOH-terminated SAMs with Ca-P coating. In addition, although the FN monolayer coverage is higher on Ca-P-coated - NH2-terminated SAMs and SiOx surfaces, higher levels of ALP activity and more cell growth are obtained on Ca-P-coated - OH- and - COOH-terminated SAMs. Thus, with the same Ca-P coatings, different surface functional groups have different effects on the function of osteoblastic cells. These findings represent new insights into the mechanism of bioactivity of BG and thereby may lead to designing superior constructs for bone grafting. Copyright © 2008 John Wiley & Sons, Ltd
On the use of divergence statistics to make inferences about three habitats
Several coefficients, called divergences, have been suggested in the statistical literature to reflect the fact that some probability distributions are ''closer together'' than others and consequently that it may be easier to distinguish between the distributions of one pair than between those of another. When comparing three biological populations, it is often interesting to measure how two of them ''move apart'' from the third. Deals with the statistical analysis of this problem by means of bivariate divergence statistics. Provides a unified study, depicting the behaviour and relative merits of traditional divergences, by using the (h,phi), divergence family of statistics introduced by Menendez et al