232 research outputs found

    Community Exchange and Trading Systems in Germany

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    The paper provides a survey of Community Exchange and Trading Systems such as the 'Tauschringe'.Community Currencies, LETS, Tauschringe

    Towards an understanding of the global market system: a new perspective for economics

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    The paper proceeds from local economic systems which provide for the exchange of goods with currencies not convertible against any other currency. This implies, according the argument, that such systems constitute separate economic entities as distinct also from the world market system. Theoretically, they form an Archimedic Point which allows to analyse aspects of the evolution of this global system. Assuming a correspondence between actual historical development and the history of thought this perspective sheds new light on changes in consumer behavior; traditional consumption theory and „new economic approach" are interpreted as reflections of a reorientation in consumer behavior. This theoretical insight provides also a new interpretation of the appearance of the new local exchange systems. Taking account of both, the global and the local dimension, this is a contribution to the development of liberal economics as a theory of a dual economy

    "Non-Profit" Tauschsysteme: Ein LiteraturĂĽberblick

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    local exchange systems, LETS, Tauschsysteme

    The Financing of Complementary Currencies: Problems and Perspectives

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    Costs and cost coverage of complementary currencies has been neglected by researchers so far. This article provides an analysis of the different types of costs incurred and asks for appropriate means of financing such projects. External public and private sources are discussed in a critical manner. Self-financing appears to be a viable alternative; however, considering overall transaction costs, the burden to be carried by participants is considered to be a significant constraint with regard to this source. In the final part the question is discussed whether and how it can be possible to finance regional currencies that would have a significant economic impact. A scenario illustrates the potential of this feature with regard to the construction of new types of systems

    Albumin up-regulates the type II transforming growth factor-beta receptor in cultured proximal tubular cells1

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    Albumin up-regulates the type II transforming growth factor-beta receptor in cultured proximal tubular cells.BackgroundClinical and experimental observations suggest that proteinuria is not merely a marker of chronic nephropathies, but may also be involved in the progression to end-stage renal failure. Filtered proteins are taken up by tubular cells, and overwhelming this system may lead to tubular synthesis of various proinflammatory and profibrogenic cytokines, including transforming growth factor-beta (TGF-β). TGF-β acts by first binding to specific receptors. We studied in an in vitro system using a well-defined mouse proximal tubular cell line (MCT cells) whether fatty acid-free bovine albumin modulates expression of specific receptors for TGF-β.MethodsMCT (and LLC-PK1) cells were challenged in serum-free medium with different concentrations of albumin. Activation of a local renin-angiotensin system was tested by real-time polymerase chain reaction (PCR) for renin and angiotensinogen transcripts and determination of secreted angiotensin II (Ang II) by enzyme-linked immunosorbent assay (ELISA). Some cells were also treated with the AT1 receptor antagonist losartan. TGF-β receptor types I and II mRNA levels were determined by Northern analysis whereas protein abundance was measured by Western blots. To test for a functional consequence of up-regulated TGF-β receptors, MCT cells were preincubated with albumin and subsequently treated with low-dose TGF-β that normally does not induce collagen type IV expression by itself. Downstream signaling events were detected by Western blots for phosphorylated Smad2. Scatchard assays with [125I]TGF-β1 were performed to estimate affinity and number of specific binding sites. Different length TGF-β type II promoter constructs linked to CAT reporter were transiently transected into MCT cells to determine transcriptional activity.ResultsIncubation of MCT cells with 0.5 to 10 mg/mL albumin leads to an increase in type II TGF-β receptor mRNA and protein expression without influencing type I receptors. An increase in type II TGF-β receptor protein expression was detected after 12 hours of albumin incubation and was still detectable after 48 hours. The albumin-mediated increase in type II TGF-β receptor mRNA was attenuated in the presence of 1 μmol/L losartan, suggesting involvement of a local renin-angiotensin system. MCT cells treated with albumin significantly increased expression of angiotensinogen and renin transcripts and also secreted more Ang II into the culture supernatant. Analysis of transcriptional activity showed that promoter segments containing activating protein (AP-1)-binding sites are necessary for albumin-induced transcription of the TGF-β type II receptor. Binding assays revealed that albumin treatment significantly increased the overall binding sites as well as the affinity for TGF-β. This effect had functional consequences because MCT cells pretreated with albumin reacted with a stronger TGF-β–mediated phosphorylation of down-stream Smad2 and also increased collagen IV expression compared with control cells.ConclusionOur findings indicate that albumin up-regulates ligand-binding TGF-β receptors on cultured proximal tubular cells. Albumin-induced activation of local Ang II production appears to be responsible for this effect. This may amplify the matrix-stimulatory actions of TGF-β on tubular cells and could be a novel mechanism for how proteinuria exhibits pathophysiologic effects on tubular cells ultimately leading to tubulointerstitial fibrosis

    Glomerular expression of p27Kip1 in diabetic db/db mouse: Role of hyperglycemia

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    Glomerular expression of p27Kip1 in diabetic db/db mouse: Role of hyperglycemia Early diabetic nephropathy is characterized by glomerular hypertrophy. Previous studies in vitro have demonstrated that mesangial cells exposed to high glucose are arrested in the G1-phase of the cell cycle and express increased levels of the cyclin-dependent kinase inhibitor p27Kip1. The present study was performed to investigate the renal expression of p27Kip1 in db/db mice, a model of diabetes mellitus type II. Glomerular p27Kip1 protein, but not mRNA expression, was strongly enhanced in diabetic db/db mice compared with non-diabetic db/+ littermates. Immunohistochemical studies revealed that this stimulated expression was mainly restricted to the nuclei of mesangial cells and podocytes, but glomerular endothelial cells occasionally also stained positively. Quantification of p27Kip1 positive glomerular cells showed a significant increase of these cells in db/db mice compared with non-diabetic db/+ animals. Although tubular cells revealed a positive staining for p27Kip1 protein, there was no difference between db/+ and db/db mice. Immunoprecipitation experiments revealed that p27Kip1 protein associates with Cdk2 and Cdk4, but not with Cdk6. To test for the influence of hyperglycemia on cell cycle arrest and p27Kip1 expression, mesangial cells were isolated from db/+ and db/db mice. There was a similar basal proliferation when these cells were grown in normal glucose-containing medium (100 mg/dl). However, raising the glucose concentration to 275 to 450 mg/dl induced cell cycle arrest in db/+ as well as db/db mesangial cells. Increasing the medium osmolarity with D-mannitol failed to induce p27Kip1 expression in mesangial cells. Transfection of cells with p27Kip1 antisense, but not missense, phosphorothioate oligonucleotides facilitated cell cycle progression equally well in db/+ and db/db mesangial cells. Furthermore, p27Kip1 expression was comparable in both cell lines in normal glucose, but increased in high glucose medium. Our studies demonstrate that p27Kip1 expression is enhanced in diabetic db/db animals. This induction appears to be due to hyperglycemia. Expression of p27Kip1 may be important in cell cycle arrest and hypertrophy of mesangial cells during early diabetic nephropathy

    Two-level Metallization and Module Integration of Point-contacted Solar Cells

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    AbstractWe present a module integration process for back junction back contact (BJBC) solar cells featuring point contacts to the back surface field (BSF). We apply two metallization layers. A first metal layer of aluminum is deposited onto the rear side of the cell and carries the current extracted from the polarity with the larger surface area fraction, e.g. from the emitter. The second metallization layer is an Al layer on a transparent substrate that we laser-weld to the small and point-shaped regions of the other polarity, e.g. the BSF region. We use a polymer for insulation between the two metal layers. The Al layer on the substrate also serves for cell interconnection, i.e., it enables module integration. Such an interconnection structure halves the fill factor losses due to the metallization. First proof-of-principle modules show a shunt free interconnection, no laser-induced damage, and an energy conversion efficiency of up to 20.7%

    Nouvel aperçu de la stratigraphie du "Thamama supérieur" dans le domaine maritime d'Abou Dabi (Émirats Arabes Unis)

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    Le découpage stratigraphique de la partie supérieure du "Thamama" dans le domaine maritime d'Abou Dabi nécessitait une révision significative comme cela est démontré avec l'étude intégrée du champ "A". Un travail de détail en sédimentologie a permis de subdiviser cette partie de la série en unités lithostratigraphiques (notons toutefois que le vocable "allostratigraphiques" serait plus précis pour définir ce type de catégories stratigraphiques) alors que la paléontologie permettait leur calage chronostratigraphique dans l'intervalle Barrémien supérieur-Aptien moyen. Un travail complémentaire focalisé sur le "Shu'aiba" a abouti à l'établissement d'une interprétation différente de celles antérieurement publiées qui se basaient sur le domaine continental d'Abou Dabi, ainsi que sur le Qatar ou l'Oman, et qu'il est également possible d'étendre à l'échelle régionale.An integrated case study of field "A" in offshore Abu Dhabi found that the stratigraphic framework for the uppermost part of the so-called "Thamama Group" required revision. Detailed sedimentological work permitted a subdivision of the succession into lithostratigraphic units (more accurately "allostratigraphic units") and the fossil content permitted their allocation to standard age-related units ranging from Late Barremian through Middle Aptian times. Additional work focused on the so-called "Shu'aiba Formation" and resulted in a new and comprehensive interpretation on a regional scale which differs from published interpretations based on onshore studies in Abu Dhabi, Qatar, and Oman

    Registered replication report on Fischer, Castel, Dodd, and Pratt (2003)

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    The attentional spatial-numerical association of response codes (Att-SNARC) effect (Fischer, Castel, Dodd, & Pratt, 2003)—the finding that participants are quicker to detect left-side targets when the targets are preceded by small numbers and quicker to detect right-side targets when they are preceded by large numbers—has been used as evidence for embodied number representations and to support strong claims about the link between number and space (e.g., a mental number line). We attempted to replicate Experiment 2 of Fischer et al. by collecting data from 1,105 participants at 17 labs. Across all 1,105 participants and four interstimulus-interval conditions, the proportion of times the effect we observed was positive (i.e., directionally consistent with the original effect) was .50. Further, the effects we observed both within and across labs were minuscule and incompatible with those observed by Fischer et al. Given this, we conclude that we failed to replicate the effect reported by Fischer et al. In addition, our analysis of several participant-level moderators (finger-counting habits, reading and writing direction, handedness, and mathematics fluency and mathematics anxiety) revealed no substantial moderating effects. Our results indicate that the Att-SNARC effect cannot be used as evidence to support strong claims about the link between number and space
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