Individual Development Accounts for Housing Policy: Analysis of Individual and Program Characteristics

Homeownership is a desirable goal for most Americans and is considered an integral part of the American Dream. Empirical studies indicate homeownership has many positive outcomes. However, homeownership is not prevalent among low-income populations. Individual Development Accounts (IDAs) are matched savings accounts designed to help the working poor save for a home or other assets. This paper examines the savings outcomes of IDA participants saving for a home in the American Dream Policy Demonstration, which was the first large-scale test of IDAs. Data were collected from 1997 to 2001 on 1176 participants saving to purchase a home. Results indicate that low-income IDA participants can successfully save when provided structured opportunities. This paper examines individual and program characteristics that are important to explaining saving behaviors. Implications for policy makers, program administrators, and future research are given.     

Graphene oxide influence on selected properties of polymer fuel cells based on Nafion

Graphene oxide (GO) was used as an additive to the anode, to modify the electrochemical properties of polymer fuel cells (PEMFC) based on Nafion. GO was obtained by modified Hummers method and fully characterized by Raman, FTIR, X-ray, TEM, electrochemically (CV) and Surface Area and Porosity Analyzer. PEMFC with a GO-based anode containing about 30% less Pt, was constructed and compared with a cell with standard anodes. The electrodes were electrochemically tested at 25 and 60 °C. A maximum power density of 134 mW/cm² with a current density of 374 mA/cm² was achieved for PEMFC with GO-based anode at 60 °C. The electrochemical surface area (ECSA) of the PEMFC with GO-based anode was about two times higher than that of the reference device. The electrochemical characterization as well as the Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) analysis indicate that GO in the anode reduced Pt agglomeration, as a consequence of the increased surface area and decreased average pore width, compared with the reference electrode. Well-fitted equivalent circuits were proposed and discussed after an electrochemical impedance spectroscopy study of the constructed devices.     

The Application of the Combined Method for Selection of Optimal Excitation Parameters

The quality as well as reliability of electrical energy transmitted to consumers is one of the main parameters of successful operation of the power system. The searching of optimal coefficient＇s combination of PSS （power system stabilizer） is the main goal of this article. The possibility of application of the new combined approach for the optimal excitation＇s settings search is presented. MC （Monte Carlo） method, in order to search and select the optimal combination of excitation system, was applied. The proposed method has been researched with a mathematical model of the power system. This model has been built using Matlab/Simulink software. Paper shows advantages and disadvantages of the proposed methods.     

Effect of epidermal growth factor-like peptides on pig cumulus cell expansion, oocyte maturation, and acquisition of developmental competence in vitro: comparison with gonadotropins

The aim of this work was to assess the FSH-stimulated expression of epidermal growth factor (EGF)-like peptides in cultured cumulus-oocyte complexes (COCs) and to find out the effect of the peptides on cumulus expansion, oocyte maturation, and acquisition of developmental competence in vitro. FSH promptly stimulated expression of amphiregulin (AREG) and epiregulin (EREG), but not betacellulin (BTC) in the cultured COCs. Expression of AREG and EREG reached maximum at 2 or 4 h after FSH addition respectively. FSH also significantly stimulated expression of expansion-related genes (PTGS2, TNFAIP6, and HAS2) in the COCs at 4 and 8 h of culture, with a significant decrease at 20 h of culture. Both AREG and EREG also increased expression of the expansion-related genes; however, the relative abundance of mRNA for each gene was much lower than in the FSH-stimulated COCs. In contrast to FSH, AREG and EREG neither stimulated expression of CYP11A1 in the COCs nor an increase in progesterone production by cumulus cells. AREG and EREG stimulated maturation of oocytes and expansion of cumulus cells, although the percentage of oocytes that had reached metaphase II was significantly lower when compared to FSH-induced maturation. Nevertheless, significantly more oocytes stimulated with AREG and/or EREG developed to blastocyst stage after parthenogenetic activation when compared to oocytes stimulated with FSH alone or combinations of FSH/LH or pregnant mares serum gonadotrophin/human chorionic gonadotrophin. We conclude that EGF-like peptides do not mimic all effects of FSH on the cultured COCs; nevertheless, they yield oocytes with superior developmental competence.     

Phenolic profile in Czech white wines from different terroirs

Grapevine cv. Riesling is a traditional variety of cool climate viticulture regions to which the Czech Republic belongs too. In total 35 wine samples from 9 different terroirs of wine-growing regions in the Czech Republic were evaluated for the content of 20 phenolic compounds comprising hydroxybenzoic acids, hydroxycinnamates, stilbenes, and flavan-3-ols. Phenolic compounds were evaluated by an HPLC method. Methods of multivariate statistical analysis were used to discriminate wine samples on the basis of their geographical origin. Canonical variate analysis proved that it is possible to differentiate wines according to their geographical origin by following authenticity markers: gallic acid, caffeic acid, caftartic acid, p-coutaric acid, ferulic acid ethylester, p-coumaric acid ethylester, (+)-catechin, and (?)-epicatechin. On the basis of statistical analyses, 100% wine samples were correctly classified. The results indicate that, for the case of white wines, mainly hydroxycinnamates and flavan-3-ols can be used for differentiation of their geographical origin.     

Temperature and thermal stresses in a pad/disc during braking

A two-element model of braking process for a tribosystem consisting of the pad (the strip) sliding with the time-dependent velocity (braking at uniform retardation) on a surface of the disc (the semi-space) is studied. The dependences of temperature and thermal stresses on the boundary conditions on upper surface of the ceramic–metal strip were investigated. It was proved that there is a possibility of applying the obtained results to modelling of a thermal cracking of the frictional elements during braking.     

Production and biological activity of saponins and canavanine in alfalfa seedlings

The saponin and canavanine concentrations and pattern were analyzed in growing alfalfa seedlings (Medicago sativa L.). Accumulation of saponins and canavanine was found to follow different time courses. During the first eight days, saponin concentration rose from zero in alfalfa seeds to 8.7% in roots and 1.8% in shoots on eighth day and then slowly decreased to 7.6% in roots and 0.8% in shoots present on the 24th day. Canavanine was found in seeds at a concentration of 1 % then increased to 3.2% in seedlings on the sixth day and rapidly decreased to 0.2% per dry mass in roots and shoots on the 24th day. The effect of saponins-medicagenic acid sodium salt and medicagenic acid glycosides-on the growth ofAmaranthus andLepidium in Petri dishes and tomato (Lycopersicon) cell growth in tissue culture also was investigated. In contrast to medicagenic acid glycosides, a very strong inhibition of plant and cell growth was found as an effect of medicagenic acid.     

Enhanced Carbon Diffusion in Austenitic Stainless Steel Carburized at Low Temperature

Austenitic stainless steel AISI 316L was carburized by a novel, low-temperature gas-phase process. Using a calibrated scanning Auger microprobe (SAM) analysis of cross-sectional specimens under dynamic sputtering, we determined the fraction–depth profile of carbon. The profile is concave—very different from the shape expected for concentration-independent diffusion—and indicates a carbide-free solid solution with carbon levels up to 15 at. pct and a case depth of ≈30 μm. A Boltzmann–Matano analysis with a careful evaluation of the stochastic and potential systematic errors indicates that increasing levels of carbon significantly enhance carbon diffusion. For the highest carbon level observed (15 at. pct), the carbon diffusion coefficient is more than two orders of magnitude larger than in dilute solution. The most likely explanation for this strong increase is that carbon-induced local expansion of metal–metal atom distances, observed as an expansion of the lattice parameter, reduces the activation energy for carbon diffusion.     

Long-term residual effect of short-term fertilizer application on Ca,N and P concentrations in grasses <Emphasis Type="Italic">Nardus stricta</Emphasis> L. and <Emphasis Type="Italic">Avenella flexuosa</Emphasis> L.

The resilience (the ability of an ecosystem to recover after termination of perturbation) of plant species composition after short-term fertilizer application can take decades in sub-alpine grassland, but little attention has been paid to the resilience of nutrient concentrations in the biomass of individual plant species. In 2004, an abandoned experiment in which phosphorus, nitrogen and calcium had been applied from 1965 to 1967 was identified in the Giant Mts. (Krkonoše/Karkonosze, Czech Republic). The biomass of two dominant grasses, Nardus stricta and Avenella flexuosa, was analyzed for Ca, N and P concentrations 37 years after the last fertilizer application. In treatments with P application, the P concentration was still significantly increased in both species. The N concentration was higher in treatments with N or Ca application and the lowest in P treatments. The N:P ratio ranged from 7.7 to 16.6 and from 6.2 to 16.3 in N. stricta and A. flexuosa, respectively, and was lowest in P treatments where A. flexuosa predominated. N. stricta dominated in treatments where the biomass N:P ratio was higher than 13, whereas lower ratios were more favourable for A. flexuosa. In the case of N. stricta, the Ca concentration was increased in Ca treatments. Ca and P concentrations in N. stricta biomass were significantly positively correlated with soil plant available P and Ca concentrations, but this was not recorded for A. flexuosa. In environments with different P availability, the competitive ability of investigated species was predetermined by the N:P ratio in their biomass. As in the case of plant species composition and soil chemical properties, the resilience of Ca, N and P concentrations in the biomass of individual species can take decades in sub-alpine grassland.