716 research outputs found
Household Size Economies: Malaysian Evidence
People live in households with different size and composition and they consume a variety of goods; categorised as private and public goods. With the existence of public goods in the household, doubling the household size need not increase the consumption expenditure twofold to maintain the same standard of living. Using households’ per capita expenditure from the Household Expenditure Survey 2004-2005, we estimate the household size economies indices for household consumption goods through the Seemingly Unrelated Regression. The results suggested that the lower income households enjoy savings from a wider range of public goods compared to the higher income households.Household size economies, Seemingly Unrelated Regression, household composition, public goods, Malaysia.
“Guilt by Association” Is the Exception Rather Than the Rule in Gene Networks
Gene networks are commonly interpreted as encoding functional information in their connections. An extensively validated principle called guilt by association states that genes which are associated or interacting are more likely to share function. Guilt by association provides the central top-down principle for analyzing gene networks in functional terms or assessing their quality in encoding functional information. In this work, we show that functional information within gene networks is typically concentrated in only a very few interactions whose properties cannot be reliably related to the rest of the network. In effect, the apparent encoding of function within networks has been largely driven by outliers whose behaviour cannot even be generalized to individual genes, let alone to the network at large. While experimentalist-driven analysis of interactions may use prior expert knowledge to focus on the small fraction of critically important data, large-scale computational analyses have typically assumed that high-performance cross-validation in a network is due to a generalizable encoding of function. Because we find that gene function is not systemically encoded in networks, but dependent on specific and critical interactions, we conclude it is necessary to focus on the details of how networks encode function and what information computational analyses use to extract functional meaning. We explore a number of consequences of this and find that network structure itself provides clues as to which connections are critical and that systemic properties, such as scale-free-like behaviour, do not map onto the functional connectivity within networks
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Thesis Statement
The presentation of "mysterious power" is not my ultimate objective in painting, no more than "private symbolism" is a perfectly satisfying system of communication. The presentation of mystery arising from formal ambiguities is simply a means to order, a more or less controlled way of drawing a bead on a more or less visible target. That I choose mystery for a theme is less important than that I must make a choice, from which other things follow.
In the earliest work in this show I developed autobiographical themes. Painting #1 is an example of this. I used imagery which is directly symbolic: the box is a dwelling which equals security, worms equal destructive processes, holes reveal the abyss, and so on. This painting then has a straightforward narrative about things coming apart, whose symbolic components refer to the human situation, in other words, its allegorical. The use of color here, and to some extent in all the work, is associative, colors (as well as forms) of toys evoke childhood, a time when feelings of safety and terror alternate. Colors of carnival (the same class) enhance by contrast the theme of mutability, to create a sort of vanitas: in the midst of carnival is death.
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Preliminary Correlation of the Effects of Beveled Trailing Edges on the Hinge-Moment Characteristics of Control Surfaces
A study of available data from various tests of beveled control surfaces has been made in an attempt to develop a rational method for predicting the effects of beveled trailing edges on the hinge-moment characteristics of control surfaces in both two- and three-dimensional flow. The results of the study indicated that the change in the included angle at the control-surface trailing edge formed a convenient basis on which a correlation could be made of the effects of various profile modifications on hinge-moment characteristics. It is believed that the formulas developed will allow reasonably accurate predictions of the hinge-moment characteristics of sealed beveled control surfaces if the characteristics of the original control surfaces are known. The presence of a gap at the control-surface hinge increased the effect of beveled trailing edges on the hinge-moment characteristics at small control-surface deflections but the available data were insufficient to allow as complete a correlation as was possible for sealed controls
Exploiting single-cell expression to characterize co-expression replicability
BACKGROUND: Co-expression networks have been a useful tool for functional genomics, providing important clues about the cellular and biochemical mechanisms that are active in normal and disease processes. However, co-expression analysis is often treated as a black box with results being hard to trace to their basis in the data. Here, we use both published and novel single-cell RNA sequencing (RNA-seq) data to understand fundamental drivers of gene-gene connectivity and replicability in co-expression networks. RESULTS: We perform the first major analysis of single-cell co-expression, sampling from 31 individual studies. Using neighbor voting in cross-validation, we find that single-cell network connectivity is less likely to overlap with known functions than co-expression derived from bulk data, with functional variation within cell types strongly resembling that also occurring across cell types. To identify features and analysis practices that contribute to this connectivity, we perform our own single-cell RNA-seq experiment of 126 cortical interneurons in an experimental design targeted to co-expression. By assessing network replicability, semantic similarity and overall functional connectivity, we identify technical factors influencing co-expression and suggest how they can be controlled for. Many of the technical effects we identify are expression-level dependent, making expression level itself highly predictive of network topology. We show this occurs generally through re-analysis of the BrainSpan RNA-seq data. CONCLUSIONS: Technical properties of single-cell RNA-seq data create confounds in co-expression networks which can be identified and explicitly controlled for in any supervised analysis. This is useful both in improving co-expression performance and in characterizing single-cell data in generally applicable terms, permitting cross-laboratory comparison within a common framework
Ammonium Uptake Rates in a Seagrass Bed under Combined Waves and Currents
In coastal locations seagrass beds are exposed to various hydrodynamic forces that can include waves and/or unidirectional currents. Differences in these forces may be expected to alter nutrient (such as phosphorus and nitrogen compounds e.g., ammonium) uptake rates by seagrass leaves. We investigated in a laboratory flume how high and low velocities with the absence or presence of waves control ammonium absorption. Our results showed that low currents with waves had the highest nutrient uptake compared to all other treatments. This result was ascribed to a combination of mechanisms. The waves may have influenced turbulence and thereby the water movement around the leaf surface, whilst the low current enabled the canopy to remain upright with an open structure, thereby allowing leaves to be exposed to a greater exchange of ammonium rich water. Although, higher currents with waves might have increased turbulence, bending under the high current squeezed the canopy into a compact closed structure. This study indicates that there are broader implications of the observed mechanisms of nutrient uptake, for instance how they depend on the plant morphology such as the leaf area, length and flexibility
Keratinocyte growth factor induces angiogenesis and protects endothelial barrier function
9 pages, 6 figures, 1 table.Keratinocyte growth factor (KGF), also called fibroblast growth factor-7, is widely known as a paracrine growth and differentiation factor that is produced by mesenchymal cells and has been thought to act specifically on epithelial cells. Here it is shown to affect a new cell type, the microvascular endothelial cell. At subnanomolar concentrations KGF induced in vivo neovascularization in the rat cornea. In vitro it was not effective against endothelial cells cultured from large vessels, but did act directly on those cultured from small vessels, inducing chemotaxis with an ED50 of 0.02-0.05 ng/ml, stimulating proliferation and activating mitogen activated protein kinase (MAPK). KGF also helped to maintain the barrier function of monolayers of capillary but not aortic endothelial cells, protecting against hydrogen peroxide and vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) induced increases in permeability with an ED50 of 0.2-0.5 ng/ml. These newfound abilities of KGF to induce angiogenesis and to stabilize endothelial barriers suggest that it functions in microvascular tissue as it does in epithelial tissues to protect them against mild insults and to speed their repair after major damage.Peer reviewe
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SIVΔnef Vaccination Mobilizes Systemic and Mucosal Natural Killer Cells in Mamu A*01+ Macaques
SIV Infection Induces Accumulation of Plasmacytoid Dendritic Cells in the Gut Mucosa
Multiple studies suggest that plasmacytoid dendritic cells (pDCs) are depleted and dysfunctional during human immunodeficiency virus/simian immunodeficiency virus (HIV/SIV) infection, but little is known about pDCs in the gut—the primary site of virus replication. Here, we show that during SIV infection, pDCs were reduced 3-fold in the circulation and significantly upregulated the gut-homing marker α4β7, but were increased 4-fold in rectal biopsies of infected compared to naive macaques. These data revise the understanding of pDC immunobiology during SIV infection, indicating that pDCs are not necessarily depleted, but instead may traffic to and accumulate in the gut mucosa
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