209 research outputs found

    Optimum farm plans for beginning tenant farmers on Clarion-Webster soils (An application of linear programming)

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    Getting established in farming has become more difficult for young farmers in recent years, partly because of the increased amount of capital required to carry on a farm business. Too, the need for improvements in managerial ability has grown with the increased need for capital. The problems of farm planning thus become more acute for beginning farmers since they usually have access to relatively small amounts of capital and have limited farming experience. Many young farmers aware of the gains which may be obtained from improved farm planning, have turned to the Extension Service for assistance. Consequently, to provide the assistance requested, the Iowa Agricultural Extension Service has underway a program in farm and home planning for beginning farmers. This program is designed to provide the necessary technical information and guidance in farm organization. The success of an educational program for young farmers, however, depends on the basis on which recommendations are made. Information, based on empirical evidence, is needed to determine the way in which capital limitations affect income opportunities under different farming situations. Such information is helpful in deciding the most profitable way to invest limited funds. The amount of profits and, therefore, the length of time required to get established depend on the choice of enterprises and on how limited resources are allocated among enterprises. Hence, research was undertaken to determine and outline the alternative income opportunities, from different combinations of enterprises, open to young farmers In central Iowa. As a result, certain guideposts for use in decision-making could be established. These guideposts, which consider individual goals, managerial ability and resource supplies, should be useful as bases for directing recommendations to young farmers seeking to get established and, at the same time, maximize incomes

    Deregulated expression of HDAC9 in B cells promotes development of lymphoproliferative disease and lymphoma in mice

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    Histone deacetylase 9 (HDAC9) is expressed in B cells, and its overexpression has been observed in B-lymphoproliferative disorders, including B-cell non-Hodgkin lymphoma (B-NHL). We examined HDAC9 protein expression and copy number alterations in primary B-NHL samples, identifying high HDAC9 expression among various lymphoma entities andHDAC9copy number gains in 50% of diffuse large B-cell lymphoma (DLBCL). To study the role of HDAC9 in lymphomagenesis, we generated a genetically engineered mouse (GEM) model that constitutively expressed anHDAC9transgene throughout B-cell development under the control of the immunoglobulin heavy chain (IgH) enhancer (Eμ). Here, we report that theEμ-HDAC9GEM model develops splenic marginal zone lymphoma and lymphoproliferative disease (LPD) with progression towards aggressive DLBCL, with gene expression profiling supporting a germinal center cell origin, as is also seen in human B-NHL tumors. Analysis ofEμ-HDAC9tumors suggested that HDAC9 might contribute to lymphomagenesis by altering pathways involved in growth and survival, as well as modulating BCL6 activity and p53 tumor suppressor function. Epigenetic modifications play an important role in the germinal center response, and deregulation of the B-cell epigenome as a consequence of mutations and other genomic aberrations are being increasingly recognized as important steps in the pathogenesis of a variety of B-cell lymphomas. A thorough mechanistic understanding of these alterations will inform the use of targeted therapies for these malignancies. These findings strongly suggest a role for HDAC9 in B-NHL and establish a novel GEM model for the study of lymphomagenesis and, potentially, preclinical testing of therapeutic approaches based on histone deacetylase inhibitors

    Modelling Cell Polarization Driven by Synthetic Spatially Graded Rac Activation

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    The small GTPase Rac is known to be an important regulator of cell polarization, cytoskeletal reorganization, and motility of mammalian cells. In recent microfluidic experiments, HeLa cells endowed with appropriate constructs were subjected to gradients of the small molecule rapamycin leading to synthetic membrane recruitment of a Rac activator and direct graded activation of membrane-associated Rac. Rac activation could thus be triggered independent of upstream signaling mechanisms otherwise responsible for transducing activating gradient signals. The response of the cells to such stimulation depended on exceeding a threshold of activated Rac. Here we develop a minimal reaction-diffusion model for the GTPase network alone and for GTPase-phosphoinositide crosstalk that is consistent with experimental observations for the polarization of the cells. The modeling suggests that mutual inhibition is a more likely mode of cell polarization than positive feedback of Rac onto its own activation. We use a new analytical tool, Local Perturbation Analysis, to approximate the partial differential equations by ordinary differential equations for local and global variables. This method helps to analyze the parameter space and behaviour of the proposed models. The models and experiments suggest that (1) spatially uniform stimulation serves to sensitize a cell to applied gradients. (2) Feedback between phosphoinositides and Rho GTPases sensitizes a cell. (3) Cell lengthening/flattening accompanying polarization can increase the sensitivity of a cell and stabilize an otherwise unstable polarization

    Approaching an investigation of multi-dimensional inequality through the lenses of variety in models of capitalism

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    After a synthetic presentation of the state of poverty and inequality in the world and the contradictions incurred by economic theory in this field after decades of globalization and in the midst of a persisting global crisis, in paragraphs 2. and 3. we outline the rational for our theoretical analysis, underlining two main aspects. First of all, in paragraph 2. we recall the reasons which makes inequality a multidimensional phenomenon, while in paragraph 3. we explore the reasons why the models of capitalism theory is relevant for studying multidimensional inequality. These paragraphs emphasise that inequality is a multidimensional and cumulative phenomenon and it should not be conceived only as the result of the processes of personal and functional distribution of income and wealth, which even by themselves are intrinsically multidimensional. The basic idea is that institutions, the cobweb of relations among them and their interaction with the economic structure define the model of capitalism which characterises a specific country and this, in turn, affects the level and the dynamics of inequality. This approach is consistent with the sociological approach by Rehbein and Souza (2014), based on the analytical framework developed by Pierre Bourdieu. In paragraph 4. we outline the rational for our empirical analysis, applying the notion of institutional complementarity and examining the relationship between institutional complementarity, models of capitalism and inequality. Besides, refining Amable’s analysis (2003), we provide empirical evidence on the relationship between inequality in income distribution and models of capitalism. Additionally, basing on cluster analysis, we identify six different models of capitalism in a sample of OECD countries, provide preliminary evidence on the different level of inequality which characterises each model and suggest that no evidence supports of the idea that a single model of capitalism is taking shape in this sphere in EU. In paragraph 5. we give some hints about issues in search for a new interpretation capable to fasten together the process of increasing inequality, the notion of symbolic violence and the models of capitalism theory. In the last paragraph we focus on conclusions useful for carrying on our research agenda

    VEGF-A isoforms differentially regulate ATF-2-dependent VCAM-1 gene expression and endothelial-leukocyte interactions

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    Vascular endothelial growth factor A (VEGF-A) regulates many aspects of vascular physiology. VEGF-A stimulates signal transduction pathways that modulate endothelial outputs such as cell migration, proliferation, tubulogenesis, and cell-cell interactions. Multiple VEGF-A isoforms exist, but the biological significance of this is unclear. Here we analyzed VEGF-A isoform-specific stimulation of VCAM-1 gene expression, which controls endothelial-leukocyte interactions, and show that this is dependent on both ERK1/2 and activating transcription factor-2 (ATF-2). VEGF-A isoforms showed differential ERK1/2 and p38 MAPK phosphorylation kinetics. A key feature of VEGF-A isoform-specific ERK1/2 activation and nuclear translocation was increased phosphorylation of ATF-2 on threonine residue 71 (T71). Using reverse genetics, we showed ATF-2 to be functionally required for VEGF-A-stimulated endothelial VCAM-1 gene expression. ATF-2 knockdown blocked VEGF-A-stimulated VCAM-1 expression and endothelial-leukocyte interactions. ATF-2 was also required for other endothelial cell outputs, such as cell migration and tubulogenesis. In contrast, VCAM-1 was essential only for promoting endothelial-leukocyte interactions. This work presents a new paradigm for understanding how soluble growth factor isoforms program complex cellular outputs and responses by modulating signal transduction pathways

    Party identification and party closeness in comparative perspective

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    The present analysis uses data from 1974 and 1981 U. S. cross sections, which incorporate a panel, to compare the standard NES measure of party identification (ID) with a measure of partisanship derived from a party closeness question widely employed in cross-national research. Important features of the two scales are examined by transforming the closeness measure into a scale of very close, fairly close, not very close, and no preference corresponding to the seven-point ID scale. The scales are highly correlated and are similar in their reliability. More than 75% of the “independents” in the ID scale choose a party in the closeness version, and over half of these select the “fairly close” category. Respondents do not volunteer that they are independents when that alternative is not stated in the question.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45482/1/11109_2004_Article_BF00990552.pd
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