72 research outputs found
Biosynthesis of amino acids by Oxalobacter formigenes: analysis using 13C-NMR
The gram-negative anaerobe Oxalobacter formigenes, grows on oxalate as the principal carbon and energy source, but a small amount of acetate is also required for growth. Experiments were conducted to determine the distribution and the position of label in cellular amino acids from cells grown on [13C]oxalate, [13C]acetate (1-13C, 2-13C, and U-13C), and 13CCO3. The labeling pattern (determined with NMR spectroscopy) of amino acids was consistent with their formation through common biosynthetic pathways. The majority of the carbons in the amino acids that are usually derived from pyruvate, oxaloacetate, α-ketoglutarate, 3-phosphoglycerate, and carbon in the aromatic amino acids were labeled by oxalate. Carbon from 13CO3 was assimilated primarily into amino acids expected to be derived from oxaloacetate and α-ketoglutarate. Approximately 60% of the acetate that was assimilated into amino acids was incorporated as a C2 unit into proline, arginine, glutamate, and leucine. The pattern of labeling from acetate in glutamate, arginine, and proline was consistent with acetate incorporation via citrate (si)-synthase and subsequent formation of α-ketoglutarate via the first third of the tricarboxylic acid pathway. Acetate was also assimilated into amino acids derived from pyruvate and oxaloacetate, but results indicated that this incorporation was as single carbon atoms. Based on these findings, cell-free extracts were assayed for several key biosynthetic enzymes. Enzymatic activities found included glutamate dehydrogenase, phosphoenolpyruvate carboxylase, and pyruvate carboxylase. These findings are consistent with proposed biosynthetic mechanisms
A randomised controlled trial of the efficacy of the ABCD Parenting Young Adolescents Program: rationale and methodology
Background: The transition to adolescence is a time of increased vulnerability for risk taking and poor health, social and academic outcomes. Parents have an important role in protecting their children from these potential harms. While the effectiveness of parenting programs in reducing problem behavior has been demonstrated, it is not known if parenting programs that target families prior to the onset of significant behavioral difficulties in early adolescence (9-14 years) improve the wellbeing of adolescents and their parents. This paper describes the rationale and methodology of a randomised controlled trial testing the efficacy of a parenting program for the promotion of factors known to be associated with positive adolescent outcomes, such as positive parenting practices, parent-adolescent relationships and adolescent behavior.Methods/Design: One hundred and eighty parents were randomly allocated to an intervention or wait list control group. Parents in the intervention group participated in the ABCD Parenting Young Adolescents Program, a 6-session behavioral family intervention program which also incorporates acceptance-based strategies. Participants in the Wait List control group did not receive the intervention during a six month waiting period. The study was designed to comply with recommendations of the CONSORT statement. The primary outcome measures were reduction in parent-adolescent conflict and improvements in parent-adolescent relationships. Secondary outcomes included improvements in parent psychosocial wellbeing, parenting self-efficacy and perceived effectiveness, parent-adolescent communication and adolescent behavior.Conclusions: Despite the effectiveness of parenting programs in reducing child behavioral difficulties, very few parenting programs for preventing problems in adolescents have been described in the peer reviewed literature. This study will provide data which can be used to examine the efficacy of a universal parenting interventions for the promotion of protective factors associated with adolescent wellbeing and will add to the literature regarding the relationships between parent, parenting and adolescent factors
Introduction: exploring and explaining the Asia-Pacific Partnership on Clean Development and Climate
This introduction lays the groundwork for this Special Issue by providing an overview of the Asia-Pacific Partnership on Clean Development and Climate (APP), and by introducing three main analytical themes. The first theme concerns the emergence and continuation of the APP. The contributions show that the emergence of the APP can be attributed to international factors, including the United States' rejection of the Kyoto Protocol, and its search for an alternative arena for global climate governance, and other countries' wish to maintain good relations with the US; as well as domestic factors, such as the presence of bureaucratic actors in favour of the Partnership, alignment with domestic priorities, and the potential for reaping economic benefits through participation. The second theme examines the nature of the Partnership, concluding that it falls on the very soft side of the hard-soft law continuum and that while being branded as a public-private partnership, governments remain in charge. Under the third theme, the influence which the APP exerts on the post-2012 United Nations (UN) climate change negotiations is scrutinised. The contributions show that at the very least, the APP is exerting some cognitive influence on the UN discussions through its promotion of a sectoral approach. The introduction concludes with outlining areas for future research. © Springer Science+Business Media B.V. 2009
Leveraging the macro-level environment to balance work and life: an analysis of female entrepreneurs' job satisfaction
This study investigates the interactive effect of female entrepreneursâ experience of workâlife imbalance and gender-egalitarian macro-level conditions on their job satisfaction, with the prediction that the negative linear relationship between workâlife imbalance and job satisfaction may be buffered by the presence of women-friendly action resources, emancipative values, and civic entitlements. Data pertaining to 7,392 female entrepreneurs from 44 countries offer empirical support for these predictions. Female entrepreneurs who are preoccupied with their ability to fulfill both work and life responsibilities are more likely to maintain a certain level of job satisfaction, even if they experience significant workâlife imbalances, to the extent that they operate in supportive macro-level environments
I. AN IMPROVED GAS-LIQUID CALORIMETER AND A COMPARISON WITH PREVIOUS MODELS. II. BUTTRESSING EFFECT IN 2-METHYL-3-TERT-BUTYLPYRIDINE AND 2,6-DIMETHYL-3-TERT-BUTYLPYRIDINE
Abstract not availabl
The impact of double taxation treaties on foreign direct investment: evidence from large dyadic panel data
To increase inward foreign direct investment (FDI), policy makers increasingly resort to the ratification of double taxation treaties (DTTs). However, the effectiveness of DTTs in inducing higher FDI is still open to debate, as the empirical evidence of existing studies is anything but conclusive. In contrast to earlier approaches, we use a largely unpublished dataset on bilateral FDI stocks, covering a much larger and more representative sample of host and source countries. Controlling for standard determinants of FDI and employing various econometric specifications, our results indicate that DTTs do lead to higher FDI stocks and that the effects are substantively important as well
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