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51.
Discusses recent legislative trends in child and family policy, sociopolitical forces behind those trends, and ways in which pro-children's groups can affect ongoing or future legislation. The effects of budget cuts in federal funding for daycare, child nutrition, and child support programs are described. It is asserted that, to make significant progress affecting children and families, a broader coalition of children's groups, encompassing members of both political parties and the interests of children whose mothers work at home and whose mothers are part of the work force, must be formed. Strong and effective federal agencies are needed to provide the focal point for developing and implementing policy. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
52.
Many researchers and policymakers recognize the importance of preschool education, particularly for low-income children, and the role of state governments has become increasingly prominent in providing services. At the same time, some policy analysts have urged that Head Start should be shifted from federal to state control. Others, however, believe this is inadvisable. We sought to inform the debate over whether entrusting Head Start to the states would be a sound policy decision by examining extant state preschool programs. Our survey of 31 programs that matched our criteria suggested that state-funded initiatives vary widely in design, implementation, and quality. There are some common areas of strength and weakness: States tend to be strong in domains such as classroom quality, but are weak on providing comprehensive services. Overall, we find reason for serious concern regarding Head Start devolution from federal to state control at this time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
53.
Discusses the need to reorganize the Children's Bureau in relation to the necessity of developing coordinated policies to address such problems as child abuse and neglect, unavailable and inadequate childcare, and the health risks of poor children. It is recommended that the Children's Bureau (1) become the central data base on children and families in the US, (2) promote research and demonstration projects, (3) serve as an interagency and interdepartmental coordinator of child and family programs in the federal government, and (4) disseminate information to other government agencies and the general public. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
54.
Furanocoumarins are toxic chemicals that occur naturally in edible food plants such as celery, parsnip, carrot, etc. belonging to the Apiaceae family. Lower levels of these phytochemicals are also found in citrus fruits and other crops representing the Rutaceae family. Since their presence in the human diet represents a food safety issue of concern, more knowledge is needed to reduce consumer exposure. This paper provides an overview of various factors influencing the levels of furanocoumarins in vegetables and processed commodities. Special attention is paid to the comparison of crops from organic and conventional farming systems with regard to levels of furanocoumarins and their changes during storage and processing. Copyright © 2007 Society of Chemical Industry  相似文献   
55.
56.
An in situ corrosion study of austenitic stainless steel 08CH18N10T in high temperature water was performed. The material under study is used in the construction of steam generator of PWR (pressurized water reactor) nuclear power stations and is similar to AISI 321 stainless steel.In situ 300-h tests were performed under autoclave conditions at 280 °C and 8 MPa and consisted of impedance measurements, polarization measurements and electrochemical noise measurements. The experiments were performed in deionised water with the pH adjusted to 9.5, in the presence/absence of chlorides. An additional modification of corrosivity was achieved by changing oxygen concentration.A detailed analysis of the impedance data is presented identifying in the impedance spectra contributions of oxide, corrosion reaction, double layer and diffusion process. A good agreement was found between corrosion data from electrochemical impedance spectroscopy (EIS) and that from electrochemical noise (EN) measurements. It was confirmed that the oxide response cannot be attributed to the overall oxide layer but only to the part corresponding to the space charge layer, thus indicating the semi-conductive character of the oxide.  相似文献   
57.
Antenna protein aggregation is one of the principal mechanisms considered effective in protecting phototrophs against high light damage. Commonly, it is induced, in vitro, by decreasing detergent concentration and pH of a solution of purified antennas; the resulting reduction in fluorescence emission is considered to be representative of non-photochemical quenching in vivo. However, little is known about the actual size and organization of antenna particles formed by this means, and hence the physiological relevance of this experimental approach is questionable. Here, a quasi-single molecule method, fluorescence correlation spectroscopy (FCS), was applied during in vitro quenching of LHCII trimers from higher plants for a parallel estimation of particle size, fluorescence, and antenna cluster homogeneity in a single measurement. FCS revealed that, below detergent critical micelle concentration, low pH promoted the formation of large protein oligomers of sizes up to micrometers, and therefore is apparently incompatible with thylakoid membranes. In contrast, LHCII clusters formed at high pH were smaller and homogenous, and yet still capable of efficient quenching. The results altogether set the physiological validity limits of in vitro quenching experiments. Our data also support the idea that the small, moderately quenching LHCII oligomers found at high pH could be relevant with respect to non-photochemical quenching in vivo.  相似文献   
58.
A method of the continual generation of lead or lead oxide nanoparticles for potential subsequent inhalation experiments with laboratory animals was investigated. We examined the thermal decomposition and oxidation of lead bis(2,2,6,6-tetramethyl-3,5-heptanedionate) in an externally heated tube reactor as well as the evaporation and condensation of metallic lead. The particle production dependence on experimental conditions was investigated using a scanning mobility particle sizer (SMPS), and the particle characteristics were studied using transmission electron microscopy (TEM), high-resolution TEM (HRTEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), atomic absorption spectroscopy (AAS), elemental and organic carbon analysis (EC/OC), X-ray photoelectron spectrometry (XPS), and X-ray diffraction (XRD) methods. The evaporation/condensation was evaluated as being the most suitable for inhalation experiments due to its simplicity, high production rate, and the well-defined composition of the nanoparticles.

Copyright 2015 American Association for Aerosol Research  相似文献   
59.
The developmental potential of porcine oocytes cultured in vitro was remarkably enhanced in a medium containing FGF2, LIF and IGF1 (FLI) when compared to a medium supplemented with gonadotropins and EGF (control). We analyzed the molecular background of the enhanced oocyte quality by comparing the time course of MAPK3/1 and AKT activation, and the expression of genes controlled by these kinases in cumulus-oocyte complexes (COCs) cultured in FLI and the control medium. The pattern of MAPK3/1 activation in COCs was very similar in both media, except for a robust increase in MAPK3/1 phosphorylation during the first hour of culture in the FLI medium. The COCs cultured in the FLI medium exhibited significantly higher activity of AKT than in the control medium from the beginning up to 16 h of culture; afterwards a deregulation of AKT activity occurred in the FLI medium, which was not observed in the control medium. The expression of cumulus cell genes controlled by both kinases was also modulated in the FLI medium, and in particular the genes related to cumulus-expansion, signaling, apoptosis, antioxidants, cell-to-cell communication, proliferation, and translation were significantly overexpressed. Collectively, these data indicate that both MAPK3/1 and AKT are implicated in the enhanced quality of oocytes cultured in FLI medium.  相似文献   
60.
The composition of the solutions of solid KOH in methanol has been measured by means of determinating the content of water in the equilibrium mixture. The dependence of the equilibrium reaction extent ζ1 and the concentration equilibrium constant Kc on the ratio of the initial amounts of methanol and KOH containing 0.164 and 16.27 wt‐% of water are determined and theoretically described. The concentration of CH3O¯ ions can be calculated with these results. This value is very important for the course of the alkaline catalyzed methanolysis of rapeseed oil to biodiesel, because the methoxide ions are the true catalyst of such a transesterification.  相似文献   
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