955 resultados para uses


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Plant litter and fine roots are important in maintaining soil organic carbon (C) levels as well as for nutrient cycling. The decomposition of surface-placed litter and fine roots of wheat ( Triticum aestivum ), lucerne ( Medicago sativa ), buffel grass ( Cenchrus ciliaris ), and mulga ( Acacia aneura ), placed at 10-cm and 30-cm depths, was studied in the field in a Rhodic Paleustalf. After 2 years, = 60% of mulga roots and twigs remained undecomposed. The rate of decomposition varied from 4.2 year -1 for wheat roots to 0.22 year -1 for mulga twigs, which was significantly correlated with the lignin concentration of both tops and roots. Aryl+O-aryl C concentration, as measured by 13 C nuclear magnetic resonance spectroscopy, was also significantly correlated with the decomposition parameters, although with a lower R 2 value than the lignin concentration. Thus, lignin concentration provides a good predictor of litter and fine root decomposition in the field.

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Erythropoietin (EPO) has been used widely for the treatment of anaemia associated with chronic kidney disease and cancer chemotherapy for nearly 20 years. More recently, EPO has been found to interact with its receptor (EPO-R) expressed in a large variety of non-haematopoietic tissues to induce a range of cytoprotective cellular responses, including mitogenesis, angiogenesis, inhibition of apoptosis and promotion of vascular repair through mobilization of endothelial progenitor cells from the bone marrow. Administration of EPO or its analogue, darbepoetin, promotes impressive renoprotection in experimental ischaemic and toxic acute renal failure, as evidenced by suppressed tubular epithelial apoptosis, enhanced tubular epithelial proliferation and hastened functional recovery. This effect is still apparent when administration is delayed up to 6 h after the onset of injury and can be dissociated from its haematological effects. Based on these highly encouraging results, at least one large randomized controlled trial of EPO therapy in ischaemic acute renal failure is currently underway. Preliminary experimental and clinical evidence also indicates that EPO may be renoprotective in chronic kidney disease. The purpose of the present article is to review the renoprotective benefits of different protocols of EPO therapy in the settings of acute and chronic kidney failure and the potential mechanisms underpinning these renoprotective actions. Gaining further insight into the pleiotropic actions of EPO will hopefully eventuate in much-needed, novel therapeutic strategies for patients with kidney disease.

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The c-Jun N-terminal kinases (JNKs) are members of a larger group of serine/ threonine (Ser/Thr) protein kinases from the mitogen-activated protein kinase family. JNKs were originally identified as stress-activated protein kinases in the livers of cycloheximide-challenged rats. Their subsequent purification, cloning, and naming as JNKs have emphasized their ability to phosphorylate and activate the transcription factor c-Jun. Studies of c-Jun and related transcription factor substrates have provided clues about both the preferred substrate phosphorylation sequences and additional docking domains recognized by JNK There are now more than 50 proteins shown to be substrates for JNK These include a range of nuclear substrates, including transcription factors and nuclear hormone receptors, heterogeneous nuclear ribonucleoprotein K and the Pol I-specific transcription factor TIF-IA, which regulates ribosome synthesis. Many nonnuclear substrates have also been characterized, and these are involved in protein degradation (e.g., the E3 ligase Itch), signal transduction (e.g., adaptor and scaffold proteins and protein kinases), apoptotic cell death (e.g., mitochondrial Bcl2 family members), and cell movement (e.g., paxillin, DCX, microtubule-associated proteins, the stathmin family member SCG10, and the intermediate filament protein keratin 8). The range of JNK actions in the cell is therefore likely to be complex. Further characterization of the substrates of JNK should provide clearer explanations of the intracellular actions of the JNKs and may allow new avenues for targeting the JNK pathways with therapeutic agents downstream of JNK itself.

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Regular monitoring of wastewater characteristics is undertaken on most wastewater treatment plants. The data acquired during this process are usually filed and forgotten. However, systematic analysis of these data can provide useful insights into plant behaviour. Conventional graphical techniques are inadequate to give a good overall picture of how wastewater characteristics vary, with time and along the lagoon system. An approach based on the use of contour plots was devised that largely overcomes this problem. Superimposition of contour plots for different parameters can be used to gain a qualitative understanding of the nature and strength of relationships between the parameters. This is illustrated in an analysis of monitoring data for lagoon 115 East at the Western Treatment Plant, near Melbourne, Australia. In this illustrative analysis, relationships between ammonia removal rates and parameters such as chlorophyll a level and temperature are explored using a contour plot superimposition approach. It is concluded that this approach can help improve our understanding, not only of lagoon systems, but of other wastewater treatment systems as well.

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The assertion about the peculiarly intricate and complex character of social phenomena has, in much of social discourse, a virtually uncontested tradition. A significant part of the premise about the complexity of social phenomena is the conviction that it complicates, perhaps even inhibits the development and application of social scientific knowledge. Our paper explores the origins, the basis and the consequences of this assertion and asks in particular whether the classic complexity assertion still deserves to be invoked in analyses that ask about the production and the utilization of social scientific knowledge in modern society. We refer to one of the most prominent and politically influential social scientific theories, John Maynard Keynes' economic theory as an illustration. We conclude that, the practical value of social scientific knowledge is not necessarily dependent on a faithful, in the sense of complete, representation of (complex) social reality. Practical knowledge is context sensitive if not project bound. Social scientific knowledge that wants to optimize its practicality has to attend and attach itself to elements of practical social situations that can be altered or are actionable by relevant actors. This chapter represents an effort to re-examine the relation between social reality, social scientific knowledge and its practical application. There is a widely accepted view about the potential social utility of social scientific knowledge that invokes the peculiar complexity of social reality as an impediment to good theoretical comprehension and hence to its applicability.

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Purpose - The objective of this paper is to uncover the underlying dimensions of, and examine the similarities and differences in, personal uses of advertising, perceived socio-economic effects of advertising, and consumer beliefs and attitudes toward advertising in Bulgaria and Romania. Moreover, it aims to identify the relative importance of the predictors of attitudes toward advertising in the two countries. Design/methodology/approach - The paper draws upon findings of previous research and theoretical developments by Bauer and Greyser, Sandage and Leckenby, and Pollay and Mittal. The study uses a stratified random sample of 947 face-to-face interviews with adult respondents from major urban areas in Bulgaria (507) and Romania (440). Variables are measured on multi-item scales as a typical application of the reflective indicator model. Findings - Results show that there are significant differences between Romanian and Bulgarian respondents in terms of their attitudes toward advertising. Romanians are more positive about advertising as an institution than the instruments of advertising. Romanians seem to accept the role of advertising in a free market economy, but have less confidence in advertising claims and techniques. Bulgarian respondents seem more sceptical toward advertising in general and are less enthusiastic about embracing the role of advertising as an institution. Moreover, Bulgarians are highly negative towards the instruments advertising uses to convey its messages to consumers. Research limitations/implications - The research findings reflect the views of urban dwellers and may not be generalisable to the wider population of the two countries. Interviewer bias was reduced by eliminating verbal or non-verbal cues to the respondents, and by the use of stratified random sampling. Practical implications - The paper suggests that the regulatory role of codes of advertising practice and industry regulating bodies should be enhanced, and their ability to protect consumers enforced. Marketing campaigns should be more inclusive to involve diverse social groups and reflect generally-accepted social norms. Originality/value - This study reveals that, while general attitudes toward advertising may be similar, attitudes toward the institution and instruments of advertising may differ even in countries with geographic proximity and low cultural distance. © Emerald Group Publishing Limited.

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Preface

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An optical autocorrelator grown on a (211)B GaAs substrate that uses visible surface-emitted second-harmonic generation is demonstrated. The (211)B orientation needs TE mode excitation only, thus eliminating the problem of the beating between the TE and TM modes that is required for (100)-grown devices; it also has the advantage of giving higher upconversion efficiency than (111) growth. Values of waveguide loss and the difference in the effective refractive index between the TE(0) and TE(1) modes were also obtained from the autocorrelation experiment.

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Whiteness studies are trans-disciplinary, but here the focus is principally on sociology and social history. Firstly, I identify, elucidate and synthesize the major ways in which whiteness in this literature has hitherto been problematized, to provide a sociological view of the multidisciplinary work so far. Five interpretations are identified; whiteness as absence, as content, as a set of norms, as resources and as a contingent hierarchy. Secondly, I make some proposals regarding the whiteness problematicâs degree of pertinence to European settings, with a brief discussion of the Irish case. Finally, I argue that whiteness is useful if conceptualized in a way that sets it within the parameters of studies of racism.