2,559 research outputs found
Analysis of the transcriptional program governing meiosis and gametogenesis in yeast and mammals
During meiosis a competent diploid cell replicates its DNA once and then undergoes two consecutive divisions followed by haploid gamete diïŹerentiation. Important aspects of meiotic development that distinguish it from mitotic growth include a highly increased rate of recombination, formation of the synaptonemal complex that aligns the homologous chromosomes, as well as separation of the homologues and sister chromatids during meiosis I and II without an intervening S-phase. Budding yeast is an excellent model organism to study meiosis and gametogenesis and accordingly, to date it belongs to the best studied eukaryotic systems in this context. Knowledge coming from these studies has provided important insights into meiotic development in higher eukaryotes. This was possible because sporulation in yeast and spermatogenesis in higher eukaryotes are analogous developmental pathways that involve conserved genes. For budding yeast a huge amount of data from numerous genome-scale studies on gene expression and deletion phenotypes of meiotic development and sporulation are available. In contrast, mammalian gametogenesis has not been studied on a large-scale until recently. It was unclear if an expression proïŹling study using germ cells and testicular somatic control cells that underwent lengthy puriïŹcation procedures would yield interpretable results. We have therefore carried out a pioneering expression proïŹling study of male germ cells from Rattus norvegicus using AïŹymetrix U34A and B GeneChips. This work resulted in the ïŹrst comprehensive large-scale expression proïŹling analysis of mammalian male germ cells undergoing mitotic growth, meiosis and gametogenesis. We have identiïŹed 1268 diïŹerentially expressed genes in germ cells at diïŹerent developmental stages, which were organized into four distinct expression clusters that reïŹect somatic, mitotic, meiotic and post-meiotic cell types. This included 293 yet uncharacterized transcripts whose expression pattern suggests that they are involved in spermatogenesis and fertility. A group of 121 transcripts were only expressed in meiotic (spermatocytes) and postmeiotic germ cells (round spermatids) but not in dividing germ cells (spermatogonia),
Sertoli
cells or two somatic control tissues (brain
and skeletal muscle). Functional analysis reveals
that most of the known genes in this
group fulfill essential functions during meiosis,
spermiogenesis (the process of sperm maturation)
and fertility. Therefore it is highly possible
that some of the ïżœ30 uncharacterized transcripts
in this group also contribute to these
processes. A web-accessible database (called
reXbase, which was later on integrated into
GermOnline) has been developed for our expression
profiling study of mammalian male
meiosis, which summarizes annotation information
and shows a graphical display of expression
profiles of every gene covered in our
study.
In the budding yeast Saccharomyces cerevisiae
entry into meiosis and subsequent progression
through sporulation and gametogenesis
are driven by a highly regulated transcriptional
program activated by signal pathways
responding to nutritional and cell-type cues.
Abf1p, which is a general transcription factor,
has previously been demonstrated to participate
in the induction of numerous mitotic as
well as early and middle meiotic genes. In
the current study we have addressed the question
how Abf1p transcriptionally coordinates
mitotic growth and meiotic development on a
genome-wide level. Because ABF1 is an essential
gene we used the temperature-sensitive
allele abf1-1. A phenotypical analysis of mutant
cells revealed that ABF1 plays an important
role in cell separation during mitosis,
meiotic development, and spore formation. In
order to identify genes whose expression depends
on Abf1p in growing and sporulating
cells we have performed expression profiling
experiments using Affymetrix S98 GeneChips
comparing wild-type and abf1-1 mutant cells
at both permissive and restrictive temperature.
We have identified 504 genes whose normal expression
depends on functional ABF1. By combining
the expression profiling data with data
from genome-wide DNA binding assays (ChIPCHIP)
and in silico predictions of potential
Abf1p-binding sites in the yeast genome, we
were able to define direct target genes. Expression
of these genes decreases in the absence
of functional ABF1 and whose promotors are
bound by Abf1p and/or contain a predicted
binding site.
Among 352 such bona fide direct target genes
we found many involved in ribosome biogenesis,
translation, vegetative growth and meiotic
developement and therefore could account for
the observed growth and sporulation defects of
abf1-1 mutant cells. Furthermore, the fact that
two members of the septin family (CDC3 and
CDC10 ) were found to be direct target genes
suggests a novel role for Abf1p in cytokinesis.
This was further substantiated by the observation
that chitin localization and septin ring
formation are perturbed in abf1-1 mutant cells
Giving Permission for Creative Preaching in the Lutheran Church -- Missouri Synod: Returning to Our Creative Roots
This dissertation explores preaching, particularly within the context of The Lutheran ChurchâMissouri Synod (LCMS). The use of multi-media and interactive preaching, among other creative approaches, can effectively communicate the Gospel to all ages, engage the congregation, and relate Christ and His Word to daily life. Such creativity is found throughout Godâs Word, is seen significantly at the time of the Reformation, and has historically been part of the rich evangelical nature of the LCMS. However, in the 1960s and 1970s, there was significant upheaval within the LCMS, and part of the outcome following that time was an unstated curtailing of creativity which continues to be felt today. I examine a variety of issues that influenced this curtailing, including a major cultural shift from modernity, a breakdown of trust in authority, fear of possible recrimination, and long-standing tensions between the âpriesthood of believersâ and the Office of the Ministry, among others. To better understand the purpose of and approach to preaching, as well as the freedom given to utilize creativity and a variety of styles, I examine the Bible and the approach Jesus, Paul, and Peter had to preaching and teaching. I explore the Protestant Reformation and the significant impact Martin Luther and the other reformers had on preaching and the creativity at work in that period of history. I also examine the LCMS and what the rich history of our church body suggests can be done when it comes to creativity in ministry and in preaching. Scripture and history provide the basis for permission that has been given to all preachers of Godâs Word to employ a variety of creative approaches and styles in order to most effectively proclaim the Gospel of Jesus Christ to the people in our culture today
Kategorien von Geschlecht in Lehrwerken Deutsch als Zweit- und Fremdsprache.
Im wissenschaftlichen Diskurs gilt Gender, und die damit verbundene HeteronormativitĂ€t, mittlerweile als fest etablierte Kategorie. Auf Ă€hnliche Weise scheint sich Gender auch im Alltag der Mehrheitsgesellschaft konstituiert zu haben, wenngleich sich schnell herauskristallisieren lĂ€sst, dass die Legitimation dieser eigentlich höchst komplexen Kategorien zumeist in Alltagsmythen und Stereotypen fuĂt. Auch wenn dieser Diskurswandel insgesamt nicht ĂŒberall auf Begeisterung stöĂt , erweckt er doch den Anschein, dass es in den meisten Bereichen des Lebens einen Platz gefunden hat. Das lĂ€sst sich auch an der riesigen Menge an populĂ€rwissenschaftlichen Publikationen feststellen. Wenn sich mehr Verlage diesem Thema anzunehmen scheinen, sollte dies auch fĂŒr Lehrwerke fĂŒr den fremdsprachlichen Erwerb wie Deutsch als Fremdsprache (DaF) oder Deutsch als Zweitsprache (DaZ) gelten. Im Rahmen dieser Masterarbeit soll ausgehend von diesen Ăberlegungen untersucht werden, wie und ob die Kategorie Geschlecht in Deutsch als Zweit- und Fremdsprache Lehrwerken konstruiert und perpetuiert wird. Es soll eine exemplarische Analyse anhand des Lehrwerk Schritte plus Neu A1.1 durchgefĂŒhrt werden, um aufzuzeigen, welche sozialen Praktiken zur Festigung des zweigeschlechtlichen Diskurse genutzt werden. Da es sich bei dem gewĂ€hlten Lehrwerk um ein fĂŒr den Integrationskurs in Deutschland zugelassenes Lehrwerk handelt, wird sich die Arbeit hauptsĂ€chlich auf den deutschsprachigen Diskurs beschrĂ€nken. ZusĂ€tzlich muss auĂerdem die macht- und herrschaftskritische Bedeutung dieses Kurses mit einbezogen werden
Deutschland gefÀhrdet Europa : wie es so weit kommen konnte und was dagegen getan werden muss
The development of venture capital industry is not only about the effective operation of venture capital firm, but also its supporting environments. The venture capital firms in different countries have different operation modes, for instance, the organizational structure, the source of finance and the investment behavior. The reason of the differences is that the venture capital supporting environments such as economy, culture, laws and regulations are different in various countries. Â The objective of this research is to study the venture capital supporting environments in China and analyze the role of government on how to improve these supporting environments. After research questions are decided, the author analyzes and combines the selected previous researches in different countries in order to build a more systematic, scientific and complete theoretical framework to conduct the case study in China. Â In the case study, all seven venture capital supporting environments in China are studied. By analyzing the facts, the author finds out that some environments such as laws and policies and financial environment have developed rapidly in past years and become more and more adapt to the development of venture capital. However, some other environments, especially the culture environment have negative effects on venture capital and can not be easily changed within a short period of time. Based on these findings, the author tries to find out some possible actions that the government can do to reduce these limitations and improve the venture capital supporting environments. Â Â Key words: venture capital; supporting environment; venture business; venture capitalist
Esther (Schlecht) Fiechtner Collection
Fiechtner family BibleFiechtner family Bible ("Die Bibel oder die ganze Heilige Schrift des alten und neues Testaments nach der deutschen Ueberfetzung Dr. Martin Luthers", St. Louis: Concordia Publishing House, pages 1079 and 311
Allpass Feedback Delay Networks
In the 1960s, Schroeder and Logan introduced delay line-based allpass
filters, which are still popular due to their computational efficiency and
versatile applicability in artificial reverberation, decorrelation, and
dispersive system design. In this work, we extend the theory of allpass systems
to any arbitrary connection of delay lines, namely feedback delay networks
(FDNs). We present a characterization of uniallpass FDNs, i.e., FDNs, which are
allpass for an arbitrary choice of delays. Further, we develop a solution to
the completion problem, i.e., given an FDN feedback matrix to determine the
remaining gain parameters such that the FDN is allpass. Particularly useful for
the completion problem are feedback matrices, which yield a homogeneous decay
of all system modes. Finally, we apply the uniallpass characterization to
previous FDN designs, namely, Schroeder's series allpass and Gardner's nested
allpass for single-input, single-output systems, and, Poletti's unitary
reverberator for multi-input, multi-output systems and demonstrate the
significant extension of the design space
Do You Hear What I Hear? Discernment and Dialogue in a Secular Age
This Participatory Action Research (PAR) utilized a mixed methods approach to address an adaptive challenge in a Lutheran church in a bedroom community in a small town and rural setting. The research involved implementing PAR interventions that cultivated four spiritual capacities: see, hear, know, and say within the realm of faith formation. Results suggest the Holy Spirit initiated a process of cultural adaptation as participants began reframing their world view, having their missional imagination transformed, discerning the triune Godâs active presence, and engaging in dialogue
LOGISTICAL COSTS AND RISKS OF MARKETING GENETICALLY MODIFIED WHEAT
Genetically modified (GM) grains have increased in importance. Moving biotech grains from producers to processors is a challenge for the grain handling system that could involve increased segregations. The objective of this research is to determine how testing strategies affect the logistical costs of a grain pipeline when GM wheat is present. A logistical model was developed and simulated to analyze impacts of uncertainty in demand, receipts, test accuracy, rail deliveries, and transit time. Sensitivities were conducted on certain variables to determine their effects on logistical costs. Analysis revealed that logistical costs are impacted by the number of quality categories and uncertainties in the system. Adding GM grains increased costs due to testing requirements and increased segregation demands as the number of wheat categories rises.Genetically Modified (GM) Grains, Logistical Costs, Testing, Risk, Segregation, Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,
LOGISTICAL COSTS AND STRATEGIES FOR WHEAT SEGREGATION
Special segregations that provide unique qualities for end use products are being specified by buyers. As users of wheat become more specific about quality, the number of quality segregations that the logistical pipeline must accommodate increases. The additional cost of increased grain segregations will influence the optimal level of wheat variety segregations marketed in a supply chain. The primary objective of this research is to develop a model that captures the logistical costs of increased grain segregations in the marketing system. A simulation model was developed to add logistical uncertainty in demand, receipts, rail deliveries, and transit time. Sensitivities were conducted on certain variables to determine their effects on logistical costs. Logistical costs increase as more segregations are added. In addition, increasing uncertainty into the system raises logistical costs. Pipeline configuration also affects costs as the number of categories/storage bins present at origin may differ from the wheat categories demanded or the number of storage bins present at the export elevator.wheat, segregations, Crop Production/Industries,
Application of Randomized Branch Sampling to Conifer Trees: Estimating Crown Biomass
Randomized branch sampling (RBS) is a sampling scheme which can be implemented to estimate many different attributes of an object displaying a branched or forked form. The aboveground structure of trees (stem and branches) lends itself naturally to this type of sampling design. RBS utilizes the branching form of the crown itself to draw probability samples and generate unbiased estimates. When implemented correctly, RBS can also greatly reduce the costs in time and labor of sampling when the purpose is estimating attributes borne within crown portions of trees. However, RBS was created for and has been implemented primarily in applications on trees with a decurrent crown structure. Considerations when applying RBS to excurrent crown structures, which are a common trait of conifer species, are examined in this thesis. The applications of several RBS schemes are examined within the context of sampling to estimate green crown biomass. The way branches are aggregated into groups for sampling along the main stem is the distinction between the proposed RBS schemes in this thesis. For estimating green crown mass, RBS was found to produce estimates with accuracy between that of simple random and list sampling methods. A sample size of five or six branches was sufficient to obtain standard errors within ten percent of the actual crown weight
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