561 research outputs found
A CORRELATIONAL ANALYSIS OF A LEADERSHIP DEVELOPMENT MODEL AND CHURCH GROWTH
Organizational growth and vision can outpace leadership development, which ultimately creates frustration and decline in leadership, followership, and teamwork. To counter regression, organizations must determine the factors that hinder leadership development while creating pathways towards organizational success. Research indicates that church attendance in America is in decline, but there are exceptions to this national trend. A case study of one of the fastest growing churches in America reveals a correlation between intentionally fostering a culture of leadership development and one’s ability to continue seizing available growth opportunities. This parallel hypothesized by the researcher in this study was validated through the use of survey, interview, and statistical analysis at both the study site church and college. This case study illustrates that organizations are limited by their leadership capacity. To expand one’s capacity to grow as an organization, the senior leaders must invest in an effective leadership development process
Interactions of ADF/cofilin, Arp2/3 complex, capping protein and profilin in remodeling of branched actin filament networks
AbstractBackground: Cellular movements are powered by the assembly and disassembly of actin filaments. Actin dynamics are controlled by Arp2/3 complex, the Wiskott–Aldrich syndrome protein (WASp) and the related Scar protein, capping protein, profilin, and the actin-depolymerizing factor (ADF, also known as cofilin). Recently, using an assay that both reveals the kinetics of overall reactions and allows visualization of actin filaments, we showed how these proteins co-operate in the assembly of branched actin filament networks. Here, we investigated how they work together to disassemble the networks.Results: Actin filament branches formed by polymerization of ATP–actin in the presence of activated Arp2/3 complex were found to be metastable, dissociating from the mother filament with a half time of 500 seconds. The ADF/cofilin protein actophorin reduced the half time for both dissociation of γ-phosphate from ADP–Pi–actin filaments and debranching to 30 seconds. Branches were stabilized by phalloidin, which inhibits phosphate dissociation from ADP–Pi–filaments, and by BeF3, which forms a stable complex with ADP and actin. Arp2/3 complex capped pointed ends of ATP–actin filaments with higher affinity (Kd ∼40nM) than those of ADP–actin filaments (Kd ∼1μM), explaining why phosphate dissociation from ADP–Pi–filaments liberates branches. Capping protein prevented annealing of short filaments after debranching and, with profilin, allowed filaments to depolymerize at the pointed ends.Conclusions: The low affinity of Arp2/3 complex for the pointed ends of ADP–actin makes actin filament branches transient. By accelerating phosphate dissociation, ADF/cofilin promotes debranching. Barbed-end capping proteins and profilin allow dissociated branches to depolymerize from their free pointed ends
Evaluation of variants in the selectin genes in age-related macular degeneration
<p>Abstract</p> <p>Background</p> <p>Age-related macular degeneration (AMD) is a common disease of the elderly that leads to loss of the central visual field due to atrophic or neovascular events. Evidence from human eyes and animal models suggests an important role for macrophages and endothelial cell activation in the pathogenesis of AMD. We sought to determine whether common ancestral variants in genes encoding the selectin family of proteins are associated with AMD.</p> <p>Methods</p> <p>Expression of E-selectin, L-selectin and P-selectin was examined in choroid and retina by quantitative PCR and immunofluorescence. Samples from patients with AMD (n = 341) and controls (n = 400) were genotyped at a total of 34 SNPs in the <it>SELE</it>, <it>SELL </it>and <it>SELP </it>genes. Allele and genotype frequencies at these SNPs were compared between AMD patients and controls as well as between subtypes of AMD (dry, geographic atrophy, and wet) and controls.</p> <p>Results</p> <p>High expression of all three selectin genes was observed in the choroid as compared to the retina. Some selectin labeling of retinal microglia, drusen cores and the choroidal vasculature was observed. In the genetic screen of AMD versus controls, no positive associations were observed for <it>SELE </it>or <it>SELL</it>. One SNP in <it>SELP </it>(rs3917751) produced p-values < 0.05 (uncorrected for multiple measures). In the subtype analyses, 6 SNPs (one in <it>SELE</it>, two in <it>SELL</it>, and three in <it>SELP</it>) produced p-values < 0.05. However, when adjusted for multiple measures with a Bonferroni correction, only one SNP in <it>SELP </it>(rs3917751) produced a statistically significant p-value (p = 0.0029).</p> <p>Conclusions</p> <p>This genetic screen did not detect any SNPs that were highly associated with AMD affection status overall. However, subtype analysis showed that a single SNP located within an intron of <it>SELP </it>(rs3917751) is statistically associated with dry AMD in our cohort. Future studies with additional cohorts and functional assays will clarify the biological significance of this discovery. Based on our findings, it is unlikely that common ancestral variants in the other selectin genes (<it>SELE </it>and <it>SELL</it>) are risk factors for AMD. Finally, it remains possible that sporadic or rare mutations in <it>SELE</it>, <it>SELL</it>, or <it>SELP </it>have a role in the pathogenesis of AMD.</p
Roles of leaf in regulation of root and shoot growth from single node softwood cuttings of grape ( Vitis vinifera )
The role of leaf in regulation of root and shoot growths in single node softwood cuttings of grape ( Vitis vinifera ) was characterised. Leafy cuttings showed early rooting, vigorous root growth and subsequent shoot development. Defoliation at planting induced early sprouting, but adversely affected rooting and decreased the survival of cuttings irrespective of pre-planting treatment with 100 ΜM indole 3-acetic acid (IAA). Treatment with IAA did not affect the percent rooting of leafy cuttings but increased root and shoot growth. Leaf weight (wt) and leaf area of the cuttings showed a highly significant correlation to root wt of the new plant at 4 wk after planting, while cutting stem + petiole wt was either not or less significantly correlated to root and shoot weights of the subsequent plant. The greater the area or wt of leaf, the better the root and shoot growths, implying that leaf contributed to adventitious root growth. However, retaining the leaf for just 2 days was enough to stimulate rooting in more than 80% of the cuttings, suggesting that leaf tissue could also induce root formation. Root growth increased with the period of leaf retention but leaf removal before 3 wk triggered sprouting leading to high mortality in rooted cuttings. Bringing the leaf closer to the rooting zone by preparing leaf at base (LAB) cuttings delayed rooting and sprouting compared with the standard leaf at top (LAT) cuttings. An inhibitory effect on rooting and sprouting by the exposed upper internode region in LAB cuttings is suggested.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65538/1/j.1744-7348.2004.tb00313.x.pd
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Genetic evidence for endolithic microbial life colonizing basaltic glass/seawater interfaces
The majority of the Earth's shallow crust is composed of basalt that erupted on the seafloor and was subsequently altered by chemical exchange with seawater. One aspect of this alteration is the replacement of glass by secondary minerals, including clays. Petrographic thin sections from ODP Holes 504B and 896A revealed characteristic patterns of pitting (channels) at the interface of fresh basalt glass and secondary clay. Fluorescent dyes that bind specifically to nucleic acids (Hoechst 33342, PO-PRO-3, and Sytol 11) were used to examine thin sections for evidence of cellular life. Independent experiments with the three dyes indicated the presence of particulate nucleic acids at the interface of altered and unaltered glass, particularly at the distal tips of channels. Organic material was extracted from crushed basalts from Holes 504B and 896A and examined for the presence of microbial DNA by a polymerase chain reaction (PCR) assay. This technique detects specific ribosomal RNA genes that are present in all cellular life-forms. The PCR assays demonstrated the presence of prokaryotic genomic DNA in the rock extracts. Among the geochemical reactions that could provide energy for biological processes are the oxidation of iron, manganese, and sulfur. Electron microprobe analyses of areas of glass that appear to be affected by microbial action have low iron relative to the fresh glass. Also, elements that are consistent with the presence of cellular life, phosphate and potassium, were elevated in the channels (P is 0.02 wt% in glass and up to 1.4 wt% in channels and K is 0.01 wt% in glass and up to 2.0 wt% in channels). These data raise the possibility that chemical transformations of basalt on the seafloor are mediated by microorganisms
Animal models of hypertension: a scientific statement from the American Heart Association
Hypertension is the most common chronic disease in the world, yet the precise cause of elevated blood pressure often cannot be determined. Animal models have been useful for unraveling the pathogenesis of hypertension and for testing novel therapeutic strategies. The utility of animal models for improving the understanding of the pathogenesis, prevention, and treatment of hypertension and its comorbidities depends on their validity for representing human forms of hypertension, including responses to therapy, and on the quality of studies in those models (such as reproducibility and experimental design). Important unmet needs in this field include the development of models that mimic the discrete hypertensive syndromes that now populate the clinic, resolution of ongoing controversies in the pathogenesis of hypertension, and the development of new avenues for preventing and treating hypertension and its complications. Animal models may indeed be useful for addressing these unmet needs
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The conservation genetics juggling act: integrating genetics and ecology, science and policy
The field of conservation genetics, when properly implemented, is a constant juggling act integrating molecular genetics, ecology, and demography with applied aspects concerning managing declining species or implementing conservation laws and policies. This young field has grown substantially since the 1980s following the development of polymerase chain reaction and now into the genomics era. Our laboratory has ‘grown up’ with the field, having worked on these issues for over three decades. Our multidisciplinary approach entails understanding the behavior and ecology of species as well as the underlying processes that contribute to genetic viability. Taking this holistic approach provides a comprehensive understanding of factors that influence species persistence and evolutionary potential while considering annual challenges that occur throughout their life cycle. As a federal laboratory, we are often addressing the needs of the U.S. Fish and Wildlife Service in their efforts to list, de-list, or recover species. Nevertheless, there remains an overall communication gap between research geneticists and biologists who are charged with implementing their results. Therefore, we outline the need for a National Center for Small Population Biology to ameliorate this problem and provide organizations charged with making status decisions firmer ground from which to make their critical decisions.Keywords: conservation genetics, annual cycle, inbreeding, migratory connectivity, pedigree analyses, endangered species, effective population size, cross-seasonal interaction
Transcriptome Analysis of Zebrafish Embryogenesis Using Microarrays
Zebrafish (Danio rerio) is a well-recognized model for the study of vertebrate developmental genetics, yet at the same time little is known about the transcriptional events that underlie zebrafish embryogenesis. Here we have employed microarray analysis to study the temporal activity of developmentally regulated genes during zebrafish embryogenesis. Transcriptome analysis at 12 different embryonic time points covering five different developmental stages (maternal, blastula, gastrula, segmentation, and pharyngula) revealed a highly dynamic transcriptional profile. Hierarchical clustering, stage-specific clustering, and algorithms to detect onset and peak of gene expression revealed clearly demarcated transcript clusters with maximum gene activity at distinct developmental stages as well as co-regulated expression of gene groups involved in dedicated functions such as organogenesis. Our study also revealed a previously unidentified cohort of genes that are transcribed prior to the mid-blastula transition, a time point earlier than when the zygotic genome was traditionally thought to become active. Here we provide, for the first time to our knowledge, a comprehensive list of developmentally regulated zebrafish genes and their expression profiles during embryogenesis, including novel information on the temporal expression of several thousand previously uncharacterized genes. The expression data generated from this study are accessible to all interested scientists from our institute resource database (http://giscompute.gis.a-star.edu.sg/~govind/zebrafish/data_download.html)
National culture and operations management: a structured literature review
National culture has received a substantial amount of interest in the operations management literature. We present the first structured review of articles studying national culture in operations management. Our search returned 51 papers published in ten leading journals between 2000 and 2017. We sort and analyse the papers according to three focus areas of operations management (strategy, execution and improvement). We also analyse the papers according to whether they address the relevance of national culture, the impact of national culture or the actions managers can use to manage or mitigate the effects of national culture. We find that national culture appears as a relevant variable in all focus areas of operations management research but that the direction and strength of its impact remain undetermined. Only a handful of papers address how managers can actively deal with challenges related to national culture. We propose a research agenda and a guiding framework for future research.ISSN:0020-7543ISSN:1366-588
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