65 research outputs found

    A methodological framework for quantifying impacts of truck traffic on regional network with implications to transport policy

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    Increased global trade has promoted the importance of shipping industry and the introduction of mega-ships has created an opportunity to be more cost-effective. Because of this, the expected change in freight transportation influences the operating regimes and schedules at the port terminals. Trucks being the predominant mode of transportation used to carry the freight transport, there is a growing concern about the impact of trucks in the region. The problems are further expected to grow as the improvements to resolve them are hindered by funding shortfalls. Public agencies are therefore involved in developing comprehensive state freight plans that outline immediate and long-range plans for freight-related transportation improvements. However, for states to develop and implement investment policies that can adequately address challenges, there is a need for a policy framework that can evaluate the impact of freight. The lack of the framework makes it difficult for state/metropolitan planning organizations to implement investment strategies in the best possible way. The proposed framework in the dissertation tries to fill the gap by developing a methodological framework, which can help agencies to evaluate multiple policies and their impact on local communities. Additionally, the framework can ascertain the magnitude of impacts that the infrastructure or policy in conjunction with the change in truck traffic might have on a regional level. The developed framework thus can help decision makers to prioritize policies that will benefit both public and freight transportation needs. Three demand models are used in the framework, which is built on the principle of behavioral route choice and mode-choice assignment problem. The outputs from the demand models are further used to quantify the impact in terms of cost-benefit analysis. The dissertation includes a real-world case study demonstrating how the framework can be used to evaluate alternative policies and its impact on a regional level. To this end, the developed framework in the dissertation addresses the research questions to present stakeholder\u27s complex implications that policy can have on the region. It also answers the question of how much the change in truck demand affects the region regarding monetary costs such as safety, congestion, environment, and pavement damage. The research further provides an insight of the change in travel behavior as a result of policy decision and its effect on communities

    Class(es) of Factor-Type Estimator(s) in Presence of Measurement Error

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    When data is collected via sample survey it is assumed whatever is reported by a respondent is correct. However, given the issues of prestige bias, personal respect and honor, respondents’ self-reported data often produces over- or under- estimated values as opposed to true values regarding the variables under question. This causes measurement error to be present in sample values. This article considers the factortype estimator as an estimation tool and examines its performance under a measurement error model. Expressions of optimization are derived and theoretical results are supported by numerical examples

    Novel Approach to Hide Sensitive Association Rules by Introducing Transaction Affinity

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    In this paper, a novel approach has been proposed for hiding sensitive association rules based on the affinity between the frequent items of the transaction. The affinity between the items is defined as Jaccard similarity. This work proposes five algorithms to ensure the minimum side-effects resulting after applying sanitization algorithms to hide sensitive knowledge. Transaction affinity has been introduced which is calculated by adding the affinity of frequent items present in the transaction with the victim-item (item to be modified). Transactions are selected either by increasing or decreasing value of affinity for data distortion to hide association rules. The first two algorithms, MaxaffinityDSR and MinaffinityDSR, hide the sensitive information by selecting the victim item as the right-hand side of the sensitive association rule. The next two algorithms, MaxaffinityDSL and MinaffinityDSL, select the victim item from the left-hand side of the rule whereas the Hybrid approach picks the victim item from either the left-hand side or right-hand side. The performance of proposed algorithms has been evaluated by comparison with state-of-art methods (Algo 1.a and Algo 1.b), MinFIA, MaxFIA and Naive algorithms. The experiments were performed using the dataset generated from IBM synthetic data generator, and implementation has been performed in R language

    Notch Signaling Controls the Differentiation of Transporting Epithelia and Multiciliated Cells in the Zebrafish Pronephros

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    Epithelial tubules consist of multiple cell types that are specialized for specific aspects of organ function. In the zebrafish pronephros, multiciliated cells (MCCs) are specialized for fluid propulsion, whereas transporting epithelial cells recover filtered-blood solutes. These cell types are distributed in a \u27salt-and-pepper\u27 fashion in the pronephros, suggesting that a lateral inhibition mechanism may play a role in their differentiation. We find that the Notch ligand Jagged 2 is expressed in MCCs and that notch3 is expressed in pronephric epithelial cells. Morpholino knockdown of either jagged 2 or notch3, or mutation in mind bomb (in which Notch signaling is impaired), dramatically expands ciliogenic gene expression, whereas ion transporter expression is lost, indicating that pronephric cells are transfated to MCCs. Conversely, ectopic expression of the Notch1 a intracellular domain represses MCC differentiation. Gamma-secretase inhibition using DAPT demonstrated a requirement for Notch signaling early in pronephric development, before the pattern of MCC differentiation is apparent. Strikingly, we find that jagged 2 knockdown generates extra cilia and is sufficient to rescue the kidney cilia mutant double bubble. Our results indicate that Jagged 2/Notch signaling modulates the number of multiciliated versus transporting epithelial cells in the pronephros by way of a genetic pathway involving repression of rfx2, a key transcriptional regulator of the ciliogenesis program

    The Homodimeric Kinesin, Kif17, is Essential for Vertebrate Photoreceptor Sensory Outer Segment Development

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    Sensory cilia and intraflagellar transport (IFT), a pathway essential for ciliogenesis, play important roles in embryonic development and cell differentiation. In vertebrate photoreceptors IFT is required for the early development of ciliated sensory outer segments (OS), an elaborate organelle that sequesters the many proteins comprising the phototransduction machinery. As in other cilia and flagella, heterotrimeric members of the kinesin 2 family have been implicated as the anterograde IFT motor in OS. However, in Caenorhabditis elegans, OSM-3, a homodimeric kinesin 2 motor, plays an essential role in some, but not all sensory cilia. Kif17, a vertebrate OSM-3 homologue, is known for its role in dendritic trafficking in neurons, but a function in ciliogenesis has not been determined. We show that in zebrafish Kif17 is widely expressed in the nervous system and retina. In photoreceptors Kif17 co-localizes with IFT proteins within the OS, and co-immunoprecipitates with IFT proteins. Knockdown of Kif17 has little if any effect in early embryogenesis, including the formation of motile sensory cilia in the pronephros. However, OS formation and targeting of the visual pigment protein is severely disrupted. Our analysis shows that Kif17 is essential for photoreceptor OS development, and suggests that Kif17 plays a cell type specific role in vertebrate ciliogenesis

    \u3ci\u3eosr1\u3c/i\u3e Is Required for Podocyte Development Downstream of \u3ci\u3ewt1a\u3c/i\u3e

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    Odd-skipped related 1 (Osr1) encodes a zinc finger transcription factor required for kidney development. Osr1 deficiency in mice results in metanephric kidney agenesis, whereas knockdown or mutation studies in zebrafish revealed that pronephric nephrons require osr1 for proximal tubule and podocyte development. osr1-deficient pronephric podocyte progenitors express the Wilms\u27 tumor suppressor wt1a but do not undergo glomerular morphogenesis or express the foot process junctional markers nephrin and podocin. The function of osr1 in podocyte differentiation remains unclear, however. Here, we found by double fluorescence in situ hybridization that podocyte progenitors coexpress osr1 and wt1a. Knockdown of wt1a disrupted podocyte differentiation and prevented expression of osr1. Blocking retinoic acid signaling, which regulates wt1a, also prevented osr1 expression in podocyte progenitors. Furthermore, unlike the osr1-deficient proximal tubule phenotype, which can be rescued by manipulation of endoderm development, podocyte differentiation was not affected by altered endoderm development, as assessed by nephrin and podocin expression in double osr1/sox32-deficient embryos. These results suggest a different, possibly cell-autonomous requirement for osr1 in podocyte differentiation downstream of wt1a. Indeed, osr1-deficient embryos did not exhibit podocyte progenitor expression of the transcription factor lhx1a, and forced expression of activated forms of the lhx1a gene product rescued nephrin expression in osr1-deficient podocytes. Our results place osr1 in a framework of transcriptional regulators that control the expression of podocin and nephrin and thereby mediate podocyte differentiation

    Cytoplasmic Carboxypeptidase 5 Regulates Tubulin Glutamylation and Zebrafish Cilia Formation and Function

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    Glutamylation is a functionally important tubulin posttranslational modification enriched on stable microtubules of neuronal axons, mitotic spindles, centrioles, and cilia. In vertebrates, balanced activities of tubulin glutamyl ligase and cytoplasmic carboxypeptidase deglutamylase enzymes maintain organelle- and cell type-specific tubulin glutamylation pat terns. Tubulin glutamylation in cilia is regulated via restricted subcellular localization or ex pression of tubulin glutamyl ligases (ttlls) and nonenzymatic proteins, including the zebrafish TPR repeat protein Fleer/Ift70. Here we analyze the expression patterns of ccp deglutamy lase genes during zebrafish development and the effects of ccp gene knockdown on cilia formation, morphology, and tubulin glutamylation. The deglutamylases ccp2, ccp5, and ccp6 are expressed in ciliated cells, whereas ccp1 expression is restricted to the nervous system. Only ccp5 knockdown increases cilia tubulin glutamylation, induces ciliopathy phenotypes, including axis curvature, hydrocephalus, and pronephric cysts, and disrupts multicilia motility, suggesting that Ccp5 is the principal tubulin deglutamylase that maintains functional levels of cilia tubulin glutamylation. The ability of ccp5 knockdown to restore cilia tubulin glutamyla tion in fleer/ift70 mutants and rescue pronephric multicilia formation in both fleer- and ift88-deficient zebrafish indicates that tubulin glutamylation is a key driver of ciliogenesis

    Determination of densities, apparent molar volume and apparent molar volume of transfer of some R4NI salt solutions in NMF-DMSO mixtures using magnetic float densitometer and then to study of ionic Interaction at 303.15 K

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    1660-1665Binary solvent mixtures of different (%) compositions have been prepared at 303.15 K using tetra alkyl ammonium iodides (R4NI) of 0.02 M to 0.14 M to investigate inter ionic interaction, ion-ion and ion solvent interactions in NMF-DMSO solvent mixture containing large cations of tetra alkyl ammonium iodides (R4NI). The densities (ρ0) of binary solvent mixtures and salt solutions have been measured by magnetic float densitometer. The apparent molar volume at infinite dilution фv0, in the solvent mixtures, have been utilized to estimate the apparent molar volumes of transfer ∆фv0 (tr), for various tetra alkyl ammonium iodide salts (R4NI) from NMF-DMSO mixtures. The observed trend and variations of dielectric constant and density with different (%) composition of NMF – DMSO provide useful information about the structural interactions
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