Profiting Higher Education: What Students, Alumni and Employers Think About For-Profit Colleges

The for-profit higher education sector has attracted significant attention over the past few years -- both from enthusiasts and from critics. For-profit colleges and universities -- most notably large, national and online schools such as the University of Phoenix, DeVry University and ITT Technical Institute -- have seen a steep increase in student enrollment, from serving about 4.7 percent of the undergraduate student population in the 2000 -- 2001 academic year to about 13.3 percent in the 2011 -- 2012 academic year, peaking at nearly 14 percent in the 2010 -- 2011 academic year. And they have become increasingly visible through their ubiquitous advertisements and proactive -- some would say aggressive -- recruitment strategies. Largely missing from the discussion so far have been the perspectives of for-profit students themselves and those of employers who might hire them. This study gives voice to these central stakeholders

Beyond Business as Usual: Leaders of California's Civic Organizations Seek New Ways to Engage the Public in Local Governance

We asked leaders of California's civic and community-based organizations about their views on the state of public participation in local governance. The following report explores what these civic leaders say is working, what's not, and how public engagement can be improved. Traditional models for including the public in local decision making, these leaders say, fail to meet the needs of both residents and local officials. Most see significant value and potential in more inclusive and deliberative forms of engagement, and many agree local officials are making increasing efforts to include residents more meaningfully. Overall, this research suggests civic and community-based organizations are looking for newer and more effective ways to engage the public and may be ready for stronger collaborations with local government. The report also includes concrete recommendations for local officials and their institutions, civic leaders and their organizations, and foundations and other funders. The recommendations can help improve public engagement in local governance throughout California and, we hope, beyond

Testing the Waters: California's Local Officials Experiment with New Ways to Engage the Public

This report explores the attitudes of California's local officials toward public participation in local governance. These officials believe that the current models for including the public in local decision making fail to meet the needs of both residents and local officials. Most local officials seek broad-based participation from the public and want to hear more about approaches that have worked elsewhere. Many are already experimenting with more inclusive and deliberative forms of engagement. Overall, this study suggests California's local officials may be ready for newer and more effective ways to engage the public and for stronger collaborations with community-based organizations. The report also includes concrete recommendations for local officials and their institutions, civic leaders and their organizations, and foundations and other funders. The recommendations can help improve public engagement in local governance throughout California and, we hope, beyond

Why Let the People Decide? Elected Officials on Participatory Budgeting

This report documents findings from interviews with U.S. elected officials regarding their experience with participatory budgeting (PB). It also includes recommendations for policymakers, PB advocates and funders looking to improve and expand PB

Massenspektrometrische Methoden zur Untersuchung enzymatisch modifizierter RNA

Die Dynamik von RNA-Modifikationen ist im Bereich der Epitranskriptom-Forschung von zentraler Bedeutung. Die Wichtigkeit von RNA-modifizierenden Enzymen, welche die RNA-Modifikationsdichte beeinflussen, wird insbesondere deutlich, wenn man die Verbindung zu neurologischen Erkrankungen, geistiger Einschränkung und vielen Krebsarten kennt. Eine Aminosäuremutation im ADAT2/3-Enzymkomplex sorgt für eine Verringerung des Inosingehalts mancher tRNA-Moleküle und ist molekulare Grundlage für die Ausbildung einer schweren geistigen Beeinträchtigung in betroffenen Patienten. Ein weiteres Enzym NSUN2 methyliert mehrere Cytidine in der variablen Schleife einiger tRNA-Molekülen und seine durch einen Splicingfehler hervorgerufene Dysfunktion ist mit dem Dubowitz-Syndrom assoziiert. Die Liste der RNA-Modifikation abhängigen Krankheiten ist lang und die molekularen Grundlagen bedürfen weiterer Erforschung. Die Massenspektrometrie bietet bei der Detektion und Quantifizierung vieler RNA-Modifikationen vielversprechende Ansätze. Um das Level einer Modifikation nicht nur statisch zu bestimmen, habe ich maßgeblich bei der Entwicklung von NAIL-MS (engl. für nucleic acid isotope labeling coupled mass spectrometry) mitgewirkt. Mit dieser zur dynamischen Protein-Analyse SILAC (engl. für stable isotope labeling of amino acids in cell culture) analogen und innovativen Methode ist es möglich, zeitlich aufgelöst RNA in alte, post-methylierte und neue Nukleoside zu unterteilen und somit die dynamische Natur von RNA-Modifikationen besser zu erfassen. Nach gelungener Einführung dieser NAIL-MS-Methode in humaner Zellkultur, habe ich NAIL-MS dazu verwendet, das detaillierte Modifikationsprofil humaner Zellen mit AlkBH1, 3, 5-Enzymdefizienz zu ermitteln. Für AlkBH5, welches m6A in mRNA oxidativ demethyliert, konnte ich zusammen mit meiner Kollegin Dr. Kayla Borland eine demethylierende Aktivität in den lebenden Zellen beobachten. Sowohl AlkBH3 als auch AlkBH1 sollen m1A und m3C in tRNA demethylieren. Allerdings konnte ich mittels NAIL-MS keine demethylierende Aktivität der beiden Enzyme in tRNA oder rRNA gegenüber den möglichen Substraten m1A, m3C, m6A und m5C in vivo feststellen. Im Gegensatz dazu, konnten in vitro einige dieser Modifikations-Demethylierungen, wie erwartet, bestätigt und weitergehend absolut quantifiziert werden. Somit ist es mir gelungen, die bestehende, auf in vitro Daten beruhende Literatur zu bestätigen. Allerdings scheinen die Enzyme keine demethylierende Aktivität in ungestressten humanen Zellen zu haben. Die Komplexität humaner Zellen wird deshalb nicht nur bei der schwierigeren Wahl der Isotopenmarkierungsstrategie deutlich, sondern auch in der unerforschten Vielfalt an molekularen Adaptionsmechanismen, die für eine Kontrolle der RNA-Modifikationsdichte wichtig sind. Die NAIL-MS-Pulse-Chase-Analytik ist neben der Beobachtung bestehender RNA-Modifikationen hilfreich bei der Zuordnung in co- oder post-transkriptionelle Modifikationsprozesse. Bisherige Ergebnisse der Arbeitsgruppe deuteten darauf hin, dass viele Modifikationen in rRNA und tRNA, aber auch m6A in mRNA, nachträglich in die RNA eingebracht werden. Da m6A-modifiziernde Enzyme ausschließlich im Zellkern lokalisiert sind und an naszenten mRNAs arbeiten, wollte ich das Phänomen der post-transkriptionellen Modifikation genauer untersuchen. Durch die Verwendung des RNA-Transkriptionsinhibitors Actinomycin D (Acm D) konnte die Analyse der enzymatischen Post-Methylierung von Transkriptionsprozessen abgegrenzt werden. Der Gehalt an post-methyliertem m6A verringerte sich unter Acm D-Stress, was auf einen zeitlich limitierten Transkriptionsmechanismus in der Zelle hindeutet, in dem Hybrid-RNA aus unmarkierten und isotopenmarkierten Bausteinen aufgebaut wird. Meine Ergebnisse deuten darauf hin, dass NAIL-MS-Experimente eine zeitliche Limitation aufweisen, welche bei Experimentdesign bedacht werden müssen. Proteom- und Oligonukleotid-MS-Experimente werden hierzu weitere Erkenntnisse liefern. Die herkömmliche Oligonukleotid-MS-Analytik, die aufgrund der Benutzung von Ionenpaarreagenzien von nur wenigen Arbeitskreisen und auf speziell für diesen Zweck angeschafften Massenspektrometern durchgeführt wird, kann nicht kompatibel mit der Nukleosid-MS-Analytik verknüpft werden. Um diese Hürde zu beseitigen, habe ich eine Oligonukleotid-LC-Methode etabliert, mit deren Hilfe sich ionenpaarreagenzfrei, MS-schonend und kontaminationsarm, RNAs sequenzspezifisch analysieren lassen. Modifikationen in enzymatisch-modifizierter in vitro transkribierter (IVT) tRNA können somit chromatographisch von unmodifizierter getrennt, sequenziell nachgewiesen und quantifiziert werden. Die Deaminierung von Adenosin zu Inosin in der Anticodonschleife der IVT tRNAValAAC konnte ich quantitativ und positionsgenau bestimmen. Die Methode basiert auf einem spezifischen RNase T1-Verdau, mit dem auch RNA-Modifikationen in nativer totaler tRNA kartiert werden können. Zusammenfassend lässt sich sagen, dass sowohl mit der NAIL-MS als auch mit der Oligonukleotid-MS-Analytik das Wissen über RNA-Modifikationen, ihre Mechanismen und ihre Dynamik vergrößert wird und es für klinische Zwecke in der Behandlung von Krankheiten und zur Qualitätskontrolle einer wachsenden Zahl an RNA-basierten Medikamenten und Vakzinen genutzt werden kann.The dynamics of RNA modifications are important to the field of epitranscriptome research. The importance of RNA-modifying enzymes influencing RNA modification density becomes particularly clear when the link to neurological diseases, mental retardation and many cancer diseases is known. An amino acid mutation in the ADAT2/3 enzyme complex causes a reduction in the inosine content of some tRNA molecules and serves as molecular basis for the development of severe mental retardation in affected patients. Another enzyme called NSUN2 methylates several cytidines in the variable loop of some tRNA molecules and its dysfunction caused by a splicing defect is associated with the Dubowitz syndrome. The list of RNA modification-dependent diseases is long and the molecular basis requires further investigation. Mass spectrometry offers promising approaches in the detection and quantification of many RNA modifications. In order to determine the level of a modification not only statically, I played a major role in the development of NAIL-MS (nucleic acid isotope labeling coupled mass spectrometry). With this innovative method, which is analogous to the dynamic protein analysis SILAC (stable isotope labeling of amino acids in cell culture), it is possible to subdivide RNA into old, post-methylated and new nucleosides in a temporally resolved manner and thus better capture the dynamic nature of RNA modifications. After successfully introducing this NAIL-MS method in human cell culture, I used NAIL-MS to determine the detailed modification profile of human cells with AlkBH1, 3, 5 enzyme deficiency. For AlkBH5, which oxidatively demethylates m6A in mRNA, I was able to observe demethylation activity in the living cells together with my colleague Dr. Kayla Borland. Both AlkBH3 and AlkBH1 are reported to demethylate m1A and m3C in tRNA. However, using NAIL-MS, I could not detect any demethylation activity of both enzymes in tRNA or rRNA towards the possible substrates m1A, m3C, m6A and m5C in vivo. In contrast, some of these modification demethylations could be confirmed and further absolutely quantified in vitro, as expected. Thus, I have been able to confirm the existing literature based on in vitro data. However, the enzymes do not appear to have demethylating activity in unstressed human cells. The complexity of human cells is therefore not only evident in the more difficult choice of isotope labeling strategy, but also in the unexplored diversity of molecular adaptive mechanisms that are important for controlling RNA modification density. In addition to observing existing RNA modifications, NAIL-MS pulse-chase analysis is helpful in assigning them to co- or post-transcriptional modification processes. Previous results of the our group indicated that many modifications in rRNA and tRNA, but also m6A in mRNA, are subsequently introduced into the RNA. Since m6A-modifying enzymes are exclusively localized in the nucleus and work on nascent mRNAs, I wanted to investigate the phenomenon of post-transcriptional modification in more detail. By using the RNA transcription inhibitor Actinomycin D (Acm D), the analysis of enzymatic post-methylation could be distinguished from transcription processes. The level of post-methylated m6A decreased under Acm D stress, suggesting a time-limited transcription mechanism in the cell in which hybrid RNA is constructed from unlabeled and isotopically labeled building blocks. My results suggest that NAIL-MS experiments have a temporal limitation that needs to be considered in experimental planning. Proteome and oligonucleotide MS experiments will provide further insights into this. Conventional oligonucleotide MS analysis, which is carried out by only a few working groups due to the use of ion-pairing reagents and on dedicated mass spectrometers, cannot be linked compatibly with nucleoside MS analysis. To remove this hurdle, I have established an oligonucleotide LC method that can be used to analyze RNAs in a sequence-specific manner without the need for ion-pairing reagents, in a way that is gentle on MS and low in contamination. Modifications in enzymatically modified in vitro transcribed (IVT) tRNA can thus be chromatographically separated from unmodified ones, sequentially detected and quantified. I was able to quantitatively and positionally determine the deamination of adenosine to inosine in the anticodon loop of IVT tRNAValAAC. The method is based on a specific RNase T1 digestion, which can also be used to map RNA modifications in native total tRNA. In summary, both NAIL-MS and oligonucleotide MS analytics increase the knowledge of RNA modifications, their mechanisms and their dynamics and can be used for clinical purposes in the treatment of diseases and for quality control of a growing number of RNA-based drugs and vaccines

Ready, Willing and Able: Kansas City Parents Talk About How to Improve Schools and What They Can Do to Help

Are parents an untapped resource in improving and reimagining K -- 12 education in Kansas City? What do they think would enhance student learning and what are they willing to do to help their children get the education they deserve? These are among the questions explored in an in-depth survey of 1,566 parents with children now in public school in the Kansas City metropolitan area. This study finds the majority of parents in the Kansas City area ready, willing and able to be more engaged in their children's education at some level. For communities to reap the most benefit from additional parental involvement, it is important to understand that different parents can be involved and seek to be involved in different ways.The results of this research, detailed in the following pages, show that nearly a third of the region's parents may be ready to take on a greater role in shaping how local schools operate and advocating for reform in K -- 12 education. These parents say they would be very comfortable serving on committees focused on teacher selection and the use of school resources. Their sense of "parental engagement" extends beyond such traditional activities as attending PTA meetings, coaching sports, volunteering for bake sales, chaperoning school trips and seeing that their children are prepared for school each day. Yet, despite their broad interest in a deeper, more substantive involvement in shaping the region's school systems, relatively few of these "potential transformers" have actually participated in policy-oriented activities in the past year. Moreover, this survey finds that even though the majority of parents seem less inclined to jump into school policy debates, many say they could do more to support local schools in the more traditional school parent roles

Public Spending, By The People: Participatory Budgeting in the United States and Canada in 2014-15

From 2014 to 2015, more than 70,000 residents across the United States and Canada directly decided how their cities and districts should spend nearly $50 million in public funds through a process known as participatory budgeting (PB). PB is among the fastest growing forms of public engagement in local governance, having expanded to 46 communities in the U.S. and Canada in just 6 years.PB is a young practice in the U.S. and Canada. Until now, there's been no way for people to get a general understanding of how communities across the U.S. implement PB, who participates, and what sorts of projects get funded. Our report, "Public Spending, By the People" offers the first-ever comprehensive analysis of PB in the U.S. and Canada.Here's a summary of what we found:Overall, communities using PB have invested substantially in the process and have seen diverse participation. But cities and districts vary widely in how they implemented their processes, who participated and what projects voters decided to fund. Officials vary in how much money they allocate to PB and some communities lag far behind in their representation of lower-income and less educated residents.The data in this report came from 46 different PB processes across the U.S. and Canada. The report is a collaboration with local PB evaluators and practitioners. The work was funded by the Democracy Fund and the Rita Allen Foundation, and completed through a research partnership with the Kettering Foundation

Studien zur molekularen Evolution anhand eines präbiotisch plausiblen Katalysatorsystems

Im Fokus der Erforschung des „Ursprung des Lebens“ stehen Mechanismen zur Darstellung eines sich selbst-erhaltenden Systems ausgehend von primitiven Molekülbausteinen unter präbiotisch plausiblen Rahmenbedingungen. Dabei wird ein gradueller Prozess der Komplexitätssteigerung angenommen, welcher die Polymerisation von präbiotischen Molekülen, sowie die Assemblierung der resultierenden Polymere zu einem interaktiven Netzwerk im Bereich des Metabolismus und der Replikation umfasst. Aufgrund der Vielzahl möglicher Reaktionstypen und Reaktionsprodukte sind für den Existenzerfolg des Systems effektive Selektionsvorgänge entlang der Synthesepfade von zentraler Bedeutung. Auf molekularer Ebene könnte eine Selektion sowohl in Bezug auf die chemische Ausbeute als auch auf die Enantioselektivität möglich sein. Das Phänomen der Homochiralität von proteinogenen Aminosäuren sowie natürlichen Zuckern verdeutlicht die Wirkmächtigkeit der stattgefundenen Selektionsprozesse und bildet zugleich eine der Kernfragen des interdisziplinären Forschungsgebiets „Ursprung des Lebens“. Die vorliegende Dissertation beschreibt eine Herangehensweise zu einem chiralen, präbiotisch plausiblen Katalysatorsystem, das fähig ist, seine eigenen Bestandteile zu modifizieren und sich somit im Laufe der Generationen zu optimieren. Die Entwicklung eines solchen sich selbst-amplifizierenden Systems wurde mit dem Ziel verfolgt, Erkenntnisse zum Ursprung der Homochiralität bei natürlich vorkommenden Biomolekülen zu gewinnen. Das zweite Kapitel dieser Arbeit befasst sich mit der Synthese potentieller Organokatalysatoren, die durch Ringschlussreaktionen aus Aminosäurederivaten und Aldehyden zugänglich sind. Durch Einsatz dieser Katalysatoren in asymmetrischen α-Alkylierungsreaktionen von Aldehyden und der Bestimmung der chiralen Eigenschaften der entstandenen Produkte wurden wirksame funktionelle Gruppen für die Optimierung der Reaktionsparameter identifiziert. Alkyl-substituierte Imidazolidin-4-thione wurden im Rahmen der von MACMILLAN beschriebenen lichtinduzierten α-Funktionalisierung als präbiotisch plausible Analoga der MacMillan-Katalysatoren ermittelt. Untersuchungen zur Stabilität dieser schwefelhaltigen Heterozyklen, die von A. C. CLOSS durchgeführt wurden, zeigten die Möglichkeit des Generationswechsels infolge des Einbaus verzweigter anstelle von linearen Aldehyde auf. Aufbauend auf diesen Ergebnissen wurden in dieser Arbeit die Kinetik und Enantioselektivität der α-Cyanomethylierung von Aldehyden mit unterschiedlichen Katalysator-Derivaten mit Hilfe zeitaufgelöster in situ NMR-Messungen und chiraler gaschromatographischer Analysen untersucht. Messbare Unterschiede der Reaktionsraten und der Enantiomerenüberschüsse bei Verwendung verschiedener Vertreter der Katalysatorfamilie, unter Berücksichtigung der unterschiedlichen Bildungswahrscheinlichkeiten einzelner Isomere, belegen die Existenz von Selektionsprozessen. Aufgrund der Inkompatibilität der neu eingeführten Funktionalität von Katalyseprodukten in der Synthese des Imidazolidin-4-thion-Rückgrats, war mit dem beschriebenen System jedoch keine Teilnahme an einem Evolutionszyklus möglich. Um die katalytische Funktion solcher Strukturmotive auf der frühzeitlichen Erde weiter zu plausibilisieren, wurden die einzelnen Reaktionskomponenten an das präbiotische Szenario angepasst. Dabei wurde ein neuartiger lichtinduzierter Aktivierungsmechanismus von elektronenarmen Alkylbromiden gefunden, welcher in Abwesenheit externer Photosensibilisatoren wirksam war. Das darauffolgende Kapitel behandelt die detaillierte mechanistische Untersuchung der neuartigen Photoreaktion. Durch gezielte Einflussnahme auf die sterischen und elektronischen Eigenschaften von 2,6-disubsituierten Pyridinen wurde ein Effekt auf die chemische Ausbeute des alkylierten Aldehyds beobachtet und damit eine Beteiligung der Pyridinderivate am lichtabhängigen Schlüsselschritt erkannt. Anhand UV-Vis- und NMR-spektroskopischer Analysen wurde ein EDA-Komplex, gebildet aus dem Alkylbromid und 2,6-Lutidin, als die zentrale lichtaktive Spezies ermittelt. Mit der Bestimmung der Quantenausbeute wurde ein effektiver Radikalkettenmechanismus ausgeschlossen. Basierend auf den gewonnenen Erkenntnissen sowie der hier gewonnenen Kristallstruktur eines vergleichbaren Charge-Transfer-Komplexes wurde ein Mechanismus postuliert, der mit allen experimentellen Befunden vereinbar ist. Die erfolgreiche Übertragung der Reaktionsbedingungen auf eine Bandbreite von Nukleophilen belegt das Vorliegen eines generellen Aktivierungsmechanimus und ermöglicht die zukünftige breite Anwendung der hier beschriebenen Photoreaktion zur metallfreien C-C-Bindungsknüpfung in der synthetischen organischen Chemie. Das vierte Kapitel knüpft an die Thematik des zweiten Kapitels an und beschreibt die Synthese von präbiotisch plausiblen Carbenkatalysatoren mit dem Ziel der alternativen Aktivierung von Aldehyden durch Umpolung. Es werden drei Herangehensweisen zur Darstellung des gesättigten Thiazolidin-Carbens diskutiert, die auf der Deprotonierung, Thermolyse oder Reduktion des Heterozyklus basieren. Ergänzend zu den Studien an Imidazolidin-4-thionen des zweiten Kapitels wird ein neuartiger Zugang zu chiralen α-methylierten Aldehyden vorgestellt. Der Einsatz Aldehyd-abgeleiteter Katalysatoren in den Modifizierungsprozess derselben Aldehyde, sodass geeignete Bausteine für die nächste Katalysatorgeneration geschaffen werden, bildet das letzte fehlende Glied für die Realisierung eines molekularen Evolutionszyklus. Der synthetische Ansatz basierte auf einer zweistufigen Reaktonssequenz, welche in die säurekatalysierte Methylenierung sowie die anschließende organokatalytische Hydrierung unterteilt war. Mit Imidazolidin-4-thion-Katalysatoren wurde keine Stereokontolle unter den getesteten Bedingungen erreicht. Hingegen konnte im Rahmen einer umfassenden Optimierungsstudie von Reaktionsbedingungen, Additiven und Organokatalysatoren für den Jørgensen-Hayashi-Katalysator eine Balance gegenläufiger Katalyseparameter, d. h. der chemischen Ausbeute und der Enantioselektivität, erzielt werden. Mit dem hier vorgestellten katalytischen Protokoll, das die Darstellung von chiralen, nicht-modifizierten Reaktionsprodukten ermöglicht, wurde erstmals eine Lösungsstrategie für die direkte, organokatalytische α-Methylierung von Aldehyden aufgezeigt.Research in the field of "origin of life" focusses on the formation mechanisms of a self-sustaining system based on primitive molecular building blocks under prebiotically plausible conditions. A gradual process of increasing complexity is assumed, which includes the polymerization of prebiotic molecules and the assembly of the resulting polymers into an interactive network in the field of metabolism and replication. Due to the variety of possible reaction types and reaction products, effective selection processes along the synthesis paths are of central importance for the success of the system. At the molecular level, selection could be possible both in terms of chemical yield and enantioselectivity. The phenomenon of the homochirality of proteinogenic amino acids and natural sugars illustrates the effectiveness of the selection processes that have taken place and is also one of the core questions of the interdisciplinary research area "origin of life". The present dissertation describes an approach to a chiral, prebiotically plausible catalyst system that is capable of modifying its own components and thus optimizing itself over the course of generations. The development of such a self-amplifying system was pursued with the aim of gaining insights into the origin of homochirality in naturally occurring biomolecules. Chapter 2 deals with the synthesis of potential organocatalysts accessible by ring-closure reactions from amino acid derivatives and aldehydes. By using these catalysts in asymmetric α-alkylation reactions of aldehydes and by determining the chiral properties of the resulting products, effective functional groups for the optimization of reaction parameters were found. Alkyl-substituted imidazolidine-4-thiones were identified as prebiotically plausible analogues of MacMillan-catalysts in the light-induced α-functionalization described by MACMILLAN. Stability studies of these sulfur-containing heterocycles performed by A. C. CLOSS showed the possibility of a generation change due to the incorporation of branched aldehydes instead of linear ones. Based on these results, the present work deals with kinetics and enantioselectivity of the α-cyanomethylation of aldehydes with dfferent catalyst derivatives, which were determined by time-resolved in situ NMR measurements or chiral GC analysis. Measurable differences of reaction rates and of enantiomeric excesses, when using different representatives of the catalyst family and the different formation probability of individual catalyst isomers proved the existence of selection processes. However, due to the incompatibility of the newly introduced nitrile-functionality of catalyst products with the synthesis of the imidazolidine-4-thione backbone, the described system was not capable of participating in the first amplification step. To further plausibilize the catalytic function of such structural motifs on primitive earth, the individual reaction components were adapted to the prebiotic scenario. A novel, light-induced activation mechanism of electron-deficient alkyl bromides was found, which operated in the absence of external photosensitizers. The following chapter deals with the mechanistic investigation of the novel photoreaction. By influencing the steric and electronic properties of 2,6-disubstituted pyridines, an effect on the chemical yield of the alkylated aldehyde was observed and thus the participation of pyridine derivatives in the light-dependent key step was recognized. Using various UV-Vis- and NMR-spectroscopic analyses, an EDA complex formed from the alkyl bromide and 2,6-lutidine was identified as the central light-active species. By determining the quantum yield, an effective radical chain mechanism could be excluded. Based on the obtained findings and the crystal structure of a comparable, isolated charge-transfer complex, a mechanism was postulated that is compatible with all experimental observations. The successful transfer of reaction conditions to a broad range of nucleophiles confirms the existence of a general activation mechanism and enables the prospective broad application of the photoreaction described herein for metal-free C-C-bond formation in synthetic organic chemistry. Chapter 4 connects to the topic of chapter 2 and describes the synthesis of prebiotic plausible carbene precursors with the aim to establish a further activation mode of aldehydes by umpolung. Three approaches for the formation of a saturated thiazolidine carbene, based on deprotonation, thermolysis or reduction, are discussed. In addition, a novel approach to chiral α-methylated aldehydes is presented to supplement the studies on imidazolidine-4-thione catalysts of chapter 2. The integration of aldehyde-derived catalysts into the modification process of the same aldehydes, so that suitable building blocks for the next catalyst generation are created, was the last missing link for the realization of a molecular evolution cycle. The synthetic approach was based on a two-stage reaction sequence, consisting of acid-catalyzed methylation and subsequent organocatalytic hydrogenation. With imidazolidine-4-thione catalysts stereocontrol could not be achieved under the tested conditions. In contrast, a balance of opposite catalytic parameters, i. e. chemical yield and enantioselectivity, could be realized for the Jørgensen-Hayashi-catalyst within optimization studies of reaction conditions, additives and organocatalysts. With the novel catalytic protocol, which enables the synthesis of chiral, non-modified reaction products, a solution strategy for the direct, organocatalytic α-methylation of aldehydes was disclosed

Curbing Health-Care Costs: Are Citizens Ready to Wrestle with Tough Choices?

Health-care experts may assume that insurance shields most Americans from the actual costs of their health care, leaving them unconcerned about cost effectiveness. And, in the past, the public seemed relatively disinterested in talking about efforts to contain cost. However, this research raises the question: if we help citizens learn about and deliberate over approaches to contain costs, could they contribute to policy solutions?For this study on curbing health-care costs, average Americans, aged 40 to 65, gathered, in a series of four extended focus groups, to address cost containment in health care. When given the opportunity to learn about and deliberate over various policy proposals, focus group participants became not only willing but eager to consider complicated approaches for containing costs. And they did so thoughtfully and civilly.The research, while modest in scope, provides substantial clues for health-care leaders and policymakers regarding the approaches that the public may be more willing to accept and those that they may resist. It also provides guidance to enable leaders to better communicate with and engage the public on cost-containment approaches.Participants in the study also believed that other members of the public, as well as medical professionals and insurers, could benefit from similar opportunities to deliberate. While participants didn't reach consensus, they all reported a better understanding of viewpoints different from their own. Many remarked that the civility and quality of their deliberations was evidence that health-care leaders and policymakers could compromise

The influence of depositional environment and other dolerite intrusions on the quality of coal : a study of the Twistdraai mine area near Secunda, Southeastern Transvaal

The objective of the present study is to establish the influence of syngenetic (sedimentary environment) and of epigenetic (dolerite intrusions) factors on the quality of coal. The effect of dolerite intrusions is investigated in order to develop a prediction method for the location of such dykes and sills within the seam. Both factors are dealt with separately, but their respective impacts on the exploration and mining phases of a coalfield are compared. The sedimentary environment was established by identifying and describing eight vertically successive lithofacies associations. They are each laterally continuous and represent a certain depositional phase throughout the study area. These are related to sedimentary processes, from which a three-dimensional paleoenvironmental model is derived. Subsequently coal distribution and quality parameters are linked to the depositional features of the model. The identified depositional phases commenced with subglacial, glaciofluvial and glaciolacustrine settings, with associated Gilberttype deltas. These are followed by meandering and minor braided fluvial settings, characterized by laterally and vertically highly variable lithofacies, in which the main coal-bearing strata were formed. Coal distribution and quality parameters (ash, volatile matter and calorific value) are closely related to paleoenvironmental characteristics. Major changes of coal distribution and quality parameters are mainly associated with active and abandoned channels and these properties are less variable in floodplain settings. The effect of dolerite intrusions on the quality of coal is investigated by analysing a series of coal samples, which were taken at certain distance intervals from a dyke/coal contact. The analytical procedures include maceral analysis, vitrinite reflectivity measurements, proximate analysis, ultimate analysis and inorganic geochemistry of the coals and dolerites by means of XRF spectrometry. The lateral extent of metamorphic effects of the dolerite intrusions on the parameters of the coal are largely restricted to the width of the visually distinguishable contact aureole. Petrographic composition mainly changes due to the formation of natural coke; ultimate and proximate analysis results are primarily dependent on the petrographic composition of the unaltered coals. With increasing metamorphism they change in accordance with the rank increase and corresponding loss of volatile matter in the coals. Major and trace element concentrations become more variable with decreasing distance from an intrusion; however, little significant depletion or enrichment tendencies are noticeable. Metasomatic processes are most probably limited to an increased formation of carbonates in the cindered coals along the dyke. The vitrinite reflectivity proves to be the most sensitive parameter in the search for an anlytical tool for the prediction of intrusions. In apparently unaffected coals a distinct reflectivity gradient is discernible from bottom to top of the seam. This gradient becomes enhanced and may even be partially inverted in proximity to an intrusion. The sedimentary processes are found to be of more regional importance in respect to their impact on the type and grade of a coal. Intrusions only have very localized effects and determine small-scale variations in the rank of the surrounding coals. They necessitate, however, more attention in view of the short and medium-term mine planning.Thesis (DSc)--University of Pretoria, 1987.GeologyDScUnrestricte