934 resultados para stages of development
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engelska
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There is a rich history of social science research centering on racial inequalities that continue to be observed across various markets (e.g., labor, housing, and credit markets) and social milieus. Existing research on racial discrimination in consumer markets, however, is relatively scarce and that which has been done has disproportionately focused on consumers as the victims of race-based mistreatment. As such, we know relatively little about how consumers contribute to inequalities in their roles as perpetrators of racial discrimination. In response, in this paper we elaborate on a line of research that is only in its’ infancy stages of development and yet is ripe with opportunities to advance the literature on consumer racial discrimination and racial earnings inequities among tip dependent employees in the United States. Specifically, we analyze data derived from a large exit survey of restaurant consumers (n=378) in an attempt to replicate, extend, and further explore the recently documented effect of service providers’ race on restaurant consumers’ tipping decisions. Our results indicate that both White and Black restaurant customers discriminate against Black servers by tipping them less than their White coworkers. Importantly, we find no evidence that this Black tip penalty is the result of interracial differences in service skills possessed by Black and White servers. We conclude by delineating directions for future research in this neglected but salient area study.
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An brief history of the developments in the Iowa highway administration between 1838 and 1929.
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Thesis (Master's)--University of Washington, 2016-08
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This thesis deals with the origins of the architectural forms as expressed in the Homeric Mycenaean citadel. The Genesis of the Mycenaean Citadel is a philosophical quest which reveals the poetic dimension of the Mycenaean architecture. The Introduction deals with general theories on the subject of space, which converge into one, forming the spinal idea of the thesis. The ‘process of individuation’, the process by which a person becomes ‘in-dividual’ that is a separate, indivisible unity or ‘whole’, is a process of transformation and renewal which at collective level takes place within the citadel. This is built on the archetype which expresses both the nature of the soul as a microcosm and of the divinely ordered Cosmos. The confrontation of the rational ‘ego’ with the unconscious is the process which brings us to the ‘self’, that organising center of the human psyche which is symbolised through the centre of the citadel. . Chapter I refers to ‘the Archetype of the Mycenaean citadel’. The Mycenaean citadel, which is built on a certain pattern of placement and orientation in relation to landscape formations, reproduces images which belong to the category of the ‘archetypal mother’. On the other hand, its adjustment to a central point with ‘high’ significance, recalls the archetypal image of Shiva-Shakti. The citadel realises the concept of a Kantian ‘One-all embracing space’; it is a cosmogonic symbol but also a philosophical one. Chapter II examines the column in its dual meaning, which is expressed in one structure; column and capital unite within their symbolism the conscious and unconscious contents of the human psyche and express the archetype of wholeness and goal of the individuation process. 33 Chapter III is a philosophical research into the ‘symbolism of the triangle’, the sacred Pythagorean symbol which expresses certain cosmological beliefs about the relation between human nature and the divinely ordered Cosmos. The triangular slab over the Lion Gate is a representation of the Dionysiac ‘palingenesia’, that is the continuity of One life, which was central to the Mycenaean religion. Chapter IV deals with the tripartite ‘megaron’. The circular hearth within the four-columned hall expresses the ‘quaternity of the One’, one of the oldest religious symbols of humanity. Zeus is revealed in the ‘fiery monadic unit-cubit’ as an all-embracing god next to goddess Hestia, symbolised by the circular hearth. The ‘megaron’ expresses the alchemical quaternity and the triad but also the psychological stages of development in the process towards wholeness. In the Conclusions it is emphasised that the Mycenaean citadel was created as if in a repetition of a cosmogony. It is a ‘mandala’, the universal image which is identified with God-image in man. Moreover it is built in order to be experienced by its citizen in the process of his psychological transformation towards the ‘self’, the divine element within the psyche which unites with the divinely ordered Cosmos
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The parasitic nematode Haemonchus contortus has a major impact on the welfare and economic sustainability of small ruminant farming throughout the world. Increasing drug resistance requires the development of novel therapeutic agents. To further this process, we examined the fundamental biology of development in H. contortus, specifically, the potential role of microRNAs (miRNAs). miRNAs are short, non-coding RNA molecules that negatively regulate gene expression. In the free-living nematode Caenorhabditis elegans, miRNAs regulate a variety of genes including those involved in development. This thesis describes the expression patterns, potential targets and possible functions of miRNAs in H. contortus throughout development.
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During early vertebrate development, the correct establishment of the body axes is critical. The anterior pole of the mouse embryo is established when Distal Visceral Endoderm (DVE) cells migrate to form the Anterior Visceral Endoderm (AVE). Symmetrical expression of Lefty1, Cer1 and Dkk1 determines the direction of DVE migration and the future anterior side. In addition to the establishment of the Anterior-Posterior axis, the AVE has also been implicated in anterior neural specification. To better understand the role of the AVE in these processes, we have performed a differential screening using Affymetrix GeneChip technology with AVE cells isolated from cer1P-EGFP transgenic mouse embryos. We found 175 genes which were upregulated in the AVE and 36 genes in the Proximal-posterior sample. Using DAVID software, we characterized the AVE cell population regarding cellular component, molecular function and biological processes. Among the genes that were found to be upregulated in the AVE, several novel genes were identified. Four of these transcripts displaying high-fold change in the AVE were further characterized by in situ hybridization in early stages of development in order to validate the screening. From those four selected genes, one, denominated Adtk1, was chosen to be functionally characterized by targeted inactivation in ES cells. Adtk1 encodes for a serine/threonine kinase. Adtk1 null mutants are smaller and present short limbs due to decreased mineralization, suggesting a potential role in chondrogenesis during limb development. Taken together, these data point to the importance of reporting novel genes present in the AVE.
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The study of ichthyio-plankton stages and its relations with the environment and other organisms is therefore crucial for a correct use of fishery resources. In this context, the extraction and the analysis of the content of the digestive tract, is a key method for the identification of the diet in early larval stages, the determination of the resources they rely on and possibly a comparison with the diet of other species. Additionally this approach could be useful in determination on occurrence of species competition. This technique is preceded by the analysis of morphometric data (Blackith & Reyment, 1971; Marcus, 1990), that is the acquisition of quantitative variables measured from the morphology of the object of study. They are linear distances, count, angles and ratios. The subsequent application of multivariate statistical methods, aims to quantify the changes in morphological measures between and within groups, relating them to the type and size of prey and evaluate if some changes appear in food choices along the larvae growth.
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One of the loci responsible for strong phosphine resistance encodes dihydrolipoamide dehydrogenase (DLD). The strong co-incidence of enzyme complexes that contain DLD, and enzymes that require thiamine as a cofactor, motivated us to test whether the thiamine deficiency of polished white rice could influence the efficacy of phosphine fumigation against insect pests of stored grain. Three strains of Sitophilus oryzae (susceptible, weak and strong resistance) were cultured on white rice (thiamine deficient), brown rice or whole wheat. As thiamine is an essential nutrient, we firstly evaluated the effect of white rice on developmental rate and fecundity and found that both were detrimentally affected by this diet. The mean time to reach adult stage for the three strains ranged from 40 to 43 days on brown rice and 50–52 days on white rice. The mean number of offspring for the three strains ranged from 7.7 to 10.3 per female over a three day period on brown rice and 2.1 to 2.6 on white rice. Growth and reproduction on wheat was similar to that on brown rice except that the strongly resistant strain showed a tendency toward reduced fecundity on wheat. The susceptible strain exhibited a modest increase in tolerance to phosphine on white rice as expected if thiamine deficiency could mimic the effect of the dld resistance mutation at the rph2 locus. The strongly resistant strain did not respond to thiamine deficiency, but this was expected as these insects are already strongly resistant. We failed, however, to observe the expected synergistic increase in resistance due to combining thiamine deficiency with the weakly resistant strain. The lack of interaction between thiamine content of the diet and the resistance genotype in determining the phosphine resistance phenotype suggests that the mode of inhibition of the complexes is a critical determinant of resistance.
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International audience
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Background: WNT4 is a protein that plays a crucial role in ovarian differentiation and development in mammals, with a relatively well understood function in mammalian gonadal differentiation. The role of Wnt4 in teleost fish; however, remains unclear. In the present study, cDNAs of Wnt4a and Wnt4b were cloned and characterized in the spotted scat. The expression patterns of two Wnt4 genes in the gonads at different stages of development and in fish after treatment with 17α-methyltestosterone (MT) were investigated. Results: The tissue distribution showed that Wnt4a was expressed in various tissues, including the gonads, gills, spleen, brain, and fin. Interestingly, Wnt4b not only was expressed in the gills, brain, and spleen, but also was obviously expressed in the ovary. During gonad development, Wnt4a was highly expressed in the testis at stage I and Wnt4b was mainly expressed in the ovary at stages II–III. After MT treatment, the mRNA expression of Wnt4a increased significantly up to 40 d, and the transcript level of Wnt4b decreased at 20 d. Conclusions: These results suggest that Wnt4a may be involved in gonad development and plays a role in the process of spermatogonial proliferation. Our results also demonstrate that Wnt4b is not only expressed in the nervous system, but also in the ovary and it may be involved in ovary development of the spotted scat.
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The xeroderma pigmentosum complementation group B (XPB) protein is involved in both DNA repair and transcription in human cells. It is a component of the transcription factor IIH (TFIIH) and is responsible for DNA helicase activity during nucleotide (nt) excision repair (NER). Its high evolutionary conservation has allowed identification of homologous proteins in different organisms, including plants. In contrast to other organisms, Arabidopsis thaliana harbors a duplication of the XPB orthologue (AtXPB1 and AtXPB2), and the proteins encoded by the duplicated genes are very similar (95% amino acid identity). Complementation assays in yeast rad25 mutant strains suggest the involvement of AtXPB2 in DNA repair, as already shown for AtXPB1, indicating that these proteins may be functionally redundant in the removal of DNA lesions in A. thaliana. Although both genes are expressed in a constitutive manner during the plant life cycle, Northern blot analyses suggest that light modulates the expression level of both XPB copies, and transcript levels increase during early stages of development. Considering the high similarity between AtXPB1 and AtXPB2 and that both of predicted proteins may act in DNA repair, it is possible that this duplication may confer more flexibility and resistance to DNA damaging agents in thale cress. (C) 2004 Elsevier B.V. All rights reserved.
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The male gametophyte of the semi-aquatic fern, Marsilea vestita, produces multiciliated spermatozoids in a rapid developmental sequence that is controlled post-transcriptionally when dry microspores are placed in water. Development can be divided into two phases, mitosis and differentiation. During the mitotic phase, a series of nine successive division cycles produce 7 sterile cells and 32 spermatids in 4.5-5 hours. During the next 5-6 hours, each spermatid differentiates into a corkscrew-shaped motile spermatozoid with ~140 cilia. This document focuses on the role of motor proteins in the regulation of male gametophyte development and during ciliogenesis. In order to study the mechanisms that regulate spermatogenesis, RNAseq was used to generate a reference transcriptome that allowed us to assess the abundance of transcripts at different stages of development. Over 120 kinesin-like sequences were identified in the transcriptome that represent 56 unique kinesin transcripts. Members of the kinesin-2, -4, -5, -7, -8, -9, -12, -13, and -14 families, in addition to several plant specific and ‘orphan’ kinesins are present. Most (91%) of these kinesin transcripts change in abundance throughout gametophyte development, with 52% of kinesin mRNAs enriched during the mitotic phase and 39% enriched during differentiation. Functional analyses show that the temporal regulation of kinesin transcripts during gametogenesis directly correlates with kinesin protein function. Specifically, Marsilea makes one kinesin-2 (MvKinesin-2) and two kinesin-9 (MvKinesin-9A and MvKinesin-9B) transcripts, which are present during spermatid differentiation and ciliogenesis. Silencing experiments showed that MvKinesin-2 and MvKinesin-9A are required for ciliogenesis and motility in the Marsilea male gametophyte; however, these kinesins display atypical roles during these processes. In contrast, spermatozoids produced after the silencing of MvKinesin-9B exhibit normal morphology. MvKinesin-2 is necessary for cytokinesis as well as for regulating ciliary length and MvKinesin-9A is needed for the correct orientation of basal bodies, events not typically associated with these proteins. In addition, Marsilea makes motile, ciliated gametophytes without the help of IFT dynein, outer arm dynein, or the BBsome. These results are the first to investigate the kinesin-linked mechanisms that regulate ciliogenesis in a land plant.