The structure of biogenic habitat and epibiotic assemblages associated with the global invasive kelp Undaria pinnatifida in comparison to native macroalgae

Kelp forests dominate temperate and polar rocky coastlines and represent critical marine habitats because they support elevated rates of primary and secondary production and high biodiversity. A major threat to the stability of these ecosystems is the proliferation of non-native species, such as the Japanese kelp Undariapinnatifida (‘Wakame’), which has recently colonised natural habitats in the UK. We quantified the abundance and biomass of U. pinnatifida on a natural rocky reef habitat over 10 months to make comparisons with three native canopy-forming brown algae (Laminaria ochroleuca, Saccharina latissima, and Saccorhiza polyschides). We also examined the biogenic habitat structure provided by, and epibiotic assemblages associated with, U. pinnatifida in comparison to native macroalgae. Surveys conducted within the Plymouth Sound Special Area of Conservation indicated that U. pinnatifida is now a dominant and conspicuous member of kelp-dominated communities on natural substrata. Crucially, U. pinnatifida supported a structurally dissimilar and less diverse epibiotic assemblage than the native perennial kelp species. However, U. pinnatifida-associated assemblages were similar to those associated with Saccorhiza polyschides, which has a similar life history and growth strategy. Our results suggest that a shift towards U. pinnatifida dominated reefs could result in impoverished epibiotic assemblages and lower local biodiversity, although this could be offset, to some extent, by the climate-driven proliferation of L. ochroleuca at the poleward range edge, which provides complex biogenic habitat and harbours relatively high biodiversity. Clearly, greater understanding of the long-term dynamics and competitive interactions between these habitat-forming species is needed to accurately predict future biodiversity patterns.

Women of an uncertain age: quantifying human capital accumulation in rural Ireland in the nineteenth century

Geary and Stark find that Ireland’s post-Famine per capita GDP converged with British levels, and that this convergence was largely due to total factor productivity growth rather than mass emigration. In this article, new long-run measurements of human capital accumulation in Ireland are devised in order to facilitate a better assessment of sources of this productivity growth, including the relative contribution of men and women. This is done by exploiting the frequency at which age data heap at round ages, widely interpreted as an indicator of a population’s basic numeracy skills. Because Földvári, van Leeuwen, and van Leeuwen-Li find that gender-specific trends in this measure derived from census returns are biased by who is reporting and recording the age information, any computed numeracy trends are corrected using data from prison and workhouse registers, sources in which women ostensibly self-reported their age. The findings show that rural Irish women born early in the nineteenth century had substantially lower levels of human capital than uncorrected census data would otherwise suggest. These results are large in magnitude and thus economically significant. The speed at which women converged is consistent with Geary and Stark’s interpretation of Irish economic history; Ireland probably graduated to Europe’s club of advanced economies thanks in part to rapid advances in female human capital.

A Sustainable Century? Genuine Savings in developing and developed countries, 1900-2000

This chapter traces the long-run development of Genuine Savings (GS) using a panel of eleven countries during the twentieth century. This panel covers a number of developed countries (Great Britain, Germany, Switzerland, France, the US, and Australia) as well as a set of resource-abundant countries in Latin America (Argentina, Brazil, Chile, Colombia, and Mexico). These countries represent approximately 50 percent of the world’s output in terms of Gross Domestic Product (GDP) by 1950, and include large economies and small open economies, and resource-rich and resource-scarce countries, thus allowing us to compare their historical experiences. Components of GS considered include physical and human capital as well as resource extraction and pollution damages. Generally, we find evidence of positive GS over the course of the twentieth century, although the two World Wars and the Great Depression left considerable marks. Also, we found striking differences between Latin American and developed countries when Total Factor Productivity (TFP) is included; this could be a signal of natural resource curse or technological gaps unnoticed in previous works.

On the Economics and Politics of Mobility

Exit, Voice and Political Change: Evidence from Swedish Mass Migration to the United States. During the Age of Mass Migration, 30 million Europeans immigrated to the United States. We study the long-term political effects of this large-scale migration episode on origin communities using detailed historical data from Sweden. To instrument for emigration, we exploit severe local frost shocks that sparked an initial wave of emigration, interacted with within-country travel costs. Because Swedish emigration was highly path dependent, the initial shocks strongly predict total emigration over 50 years. Our estimates show that emigration substantially increased membership in local labor organizations, the strongest political opposition groups at the time. Furthermore, emigration caused greater strike participation, and mobilized voter turnout and support for left-wing parties in national elections. Emigration also had formal political effects, as measured by welfare expenditures and adoption of inclusive political institutions. Together, our findings indicate that large-scale emigration can achieve long-lasting effects on the political equilibrium in origin communities. Mass Migration and Technological Innovation at the Origin. This essay studies the effects of migration on technological innovations in origin communities. Using historical data from Sweden, we find that large-scale emigration caused a long-run increase in patent innovations in origin municipalities. Our IV estimate shows that a ten percent increase in emigration entails a 7 percent increase in a muncipality’s number of patents. Weighting patents by a measure of their economic value, the positive effects are further increased. Discussing possible mechanisms, we suggest that low skilled labor scarcity may be an explanation for these results.  Richer (and Holier) Than Thou? The Impact of Relative Income Improvements on Demand for Redistribution. We use a tailor-made survey on a Swedish sample to investigate how individuals' relative income affects their demand for redistribution. We first document that a majority misperceive their position in the income distribution and believe that they are poorer, relative to others, than they actually are. We then inform a subsample about their true relative income, and find that individuals who are richer than they initially thought demand less redistribution. This result is driven by individuals with prior right-of-center political preferences who view taxes as distortive and believe that effort, rather than luck, drives individual economic success. Wealth, home ownership and mobility. Rent controls on housing have long been thought to reduce labor mobility and allocative efficiency. We study a policy that allowed renters to purchase their rent-controlled apartments at below market prices, and examine the effects of home ownership and wealth on mobility. Treated individuals have a substantially higher likelihood of moving to a new home in a given year. The effect corresponds to a 30 percent increase from the control group mean. The size of the wealth shock predicts lower mobility, while the positive average effect can be explained by tenants switching from the previous rent-controlled system to market-priced condominiums. By contrast, we do not find that the increase in residential mobility leads to a greater probability of moving to a new place of work.

Hotel Profit Implications from Rising Wages and Inflation in the U.S.

Macroeconomic models based on the Phillips Curve predict that as the unemployment rate declines toward the long-run, natural rate, the pace of wage and price growth accelerates and inflation rises.1 In this paper I analyze the profitability prospects for the U.S. hotel industry in today’s relatively volatile economic environment, keeping in mind the Phillips Curve’s general principle that inflation and employment have an inverse, but relatively stable short-term relationship. Although employment and economic growth in the U.S. have been uneven in recent months, the unemployment rate has declined to less than 5 percent, which many economists believe is close to the natural rate. Growth in wages and salaries, as measured by the Employment Cost Index, has concurrently been moving upward between 2.5 and 3.0 percent during the past 12 months. At the same time, general inflation remains below levels that might typically be expected this late in the cycle, although core inflation is bumping up against the Federal Reserve’s 2-percent target. If the inflation rate continues to move upward as predicted by Phillips Curve models (and encouraged by the Federal Reserve), rising labor costs and other expenses will exert downward pressure on U.S. business profits. Backward movement up the Phillips Curve (with greater inflation) coincides with an expanding economy. In that scenario, prices of goods and services also will rise in real terms if their supply cannot keep up with demand, and producers have the ability to raise prices (absent fixed-price contracts such as leases).

Essays in International Finance and Macroeconomics

Thesis (Ph.D.)--University of Washington, 2016-08

Measuring, Modeling, and Forecasting Volatility and Correlations from High-Frequency Data

This dissertation contains four essays that all share a common purpose: developing new methodologies to exploit the potential of high-frequency data for the measurement, modeling and forecasting of financial assets volatility and correlations. The first two chapters provide useful tools for univariate applications while the last two chapters develop multivariate methodologies. In chapter 1, we introduce a new class of univariate volatility models named FloGARCH models. FloGARCH models provide a parsimonious joint model for low frequency returns and realized measures, and are sufficiently flexible to capture long memory as well as asymmetries related to leverage effects. We analyze the performances of the models in a realistic numerical study and on the basis of a data set composed of 65 equities. Using more than 10 years of high-frequency transactions, we document significant statistical gains related to the FloGARCH models in terms of in-sample fit, out-of-sample fit and forecasting accuracy compared to classical and Realized GARCH models. In chapter 2, using 12 years of high-frequency transactions for 55 U.S. stocks, we argue that combining low-frequency exogenous economic indicators with high-frequency financial data improves the ability of conditionally heteroskedastic models to forecast the volatility of returns, their full multi-step ahead conditional distribution and the multi-period Value-at-Risk. Using a refined version of the Realized LGARCH model allowing for time-varying intercept and implemented with realized kernels, we document that nominal corporate profits and term spreads have strong long-run predictive ability and generate accurate risk measures forecasts over long-horizon. The results are based on several loss functions and tests, including the Model Confidence Set. Chapter 3 is a joint work with David Veredas. We study the class of disentangled realized estimators for the integrated covariance matrix of Brownian semimartingales with finite activity jumps. These estimators separate correlations and volatilities. We analyze different combinations of quantile- and median-based realized volatilities, and four estimators of realized correlations with three synchronization schemes. Their finite sample properties are studied under four data generating processes, in presence, or not, of microstructure noise, and under synchronous and asynchronous trading. The main finding is that the pre-averaged version of disentangled estimators based on Gaussian ranks (for the correlations) and median deviations (for the volatilities) provide a precise, computationally efficient, and easy alternative to measure integrated covariances on the basis of noisy and asynchronous prices. Along these lines, a minimum variance portfolio application shows the superiority of this disentangled realized estimator in terms of numerous performance metrics. Chapter 4 is co-authored with Niels S. Hansen, Asger Lunde and Kasper V. Olesen, all affiliated with CREATES at Aarhus University. We propose to use the Realized Beta GARCH model to exploit the potential of high-frequency data in commodity markets. The model produces high quality forecasts of pairwise correlations between commodities which can be used to construct a composite covariance matrix. We evaluate the quality of this matrix in a portfolio context and compare it to models used in the industry. We demonstrate significant economic gains in a realistic setting including short selling constraints and transaction costs.

Adoecimento osteomuscular de trabalhadores portuários avulsos e o processamento do raciocínio clínico da enfermagem

Introdução: O trabalho portuário é composto por condicionantes socioambientais necessários à manutenção das funções operativas, mas que influenciam na produção de doenças osteomusculares. O conhecimento desses condicionantes instrumentaliza o raciocínio clínico da Enfermagem para o planejamento de ações em saúde. Desta forma, defende-se a tese de que “O conhecimento dos condicionantes socioambientais e pessoais do adoecimento osteomuscular do trabalhador portuário avulso fornece elementos ao processamento do raciocínio clínico da Enfermagem, para assistência em saúde do trabalhador”. Objetivos: identificar evidências científicas de adoecimento ocupacional do trabalhador portuário publicadas na literatura cientifica; caracterizar o tipo, a localização e a intensidade de sintomas osteomusculares relacionados com os condicionantes socioambientais do trabalho portuário; Relacionar as doenças osteomusculares autorreferidas por trabalhadores portuários e os condicionantes socioambientais deste trabalho. Percurso Metodológico: o estudo apresentou revisão sistemática, fundamentada no método Cochrane; e estudos descritivos e exploratórios de abordagem quantitativa, realizado por meio de entrevista semi-estruturada com 232 trabalhadores portuários avulsos. Os dados foram analisados no software Statistical Package for the Social Sciences (SPSS) 21.0, por frequência simples, proporções e testes inferenciais não-paramétricos. A tese integra o macro projeto de pesquisa “Saúde do Trabalhador, Riscos, Acidentes e Doenças Relacionadas ao Trabalho: Estudo com Trabalhadores em um Porto no Extremo Sul do Brasil”, aprovado pelo Comitê de Ética em Pesquisa da Universidade Federal do Rio Grande (CEPAS-FURG) sob parecer número 118/2013. Resultados: Na revisão sistemática, selecionaram-se 16 publicações; todas as publicações pertenceram ao nível de evidência quatro, destacando o câncer pulmonar, doenças osteomusculares e isquêmicas, com nexo causal em riscos químicos oriundos da exaustão veicular e das cargas transportadas. Nos estudos descritivos, os sintomas prevalentes foram a dor leve em membros superiores (51,7%) e intensa a insuportável na coluna vertebral (19%). Os dois adoecimentos mais autorreferidos foram lombocitalgia (36,8%; n=50 – em terra e 28,1%; n=27 – a bordo) e tendinite (27,9% - em terra e 31,3% - a bordo). Discussão: O câncer pulmonar ocupacional foi causado por componentes químicos da exaustão veicular e do amianto transportado nas operações portuárias. Com relação à saúde muscular, a idade, o tempo e a jornada de trabalho mostraram-se condicionantes importantes na identificação de sintomas e adoecimentos, e o quanto estes fatores interveem na percepção da intensidade, contribuindo no autocuidado para prevenção e tratamento. Conclusão: O conhecimento dos condicionantes socioambientais relacionados ao trabalhador e caracterizados nos ambientes de trabalho deve ser atual e pregresso, o que somado à apreensão dos sintomas e adoecimentos autorreferidos pelos trabalhadores instrumentalizou o RC, identificando uma atuação profissional em longo prazo para dirimir os adoecimentos identificados. As características clínicas obtidas, em conjunto com a literatura, conduziram ao processamento do RC da enfermagem nesta realidade, sendo a informação em saúde um ponto chave para a promoção da saúde muscular dos trabalhadores.

Rate of Belowground Carbon Allocation Differs with Successional Habit of Two Afromontane Trees

Background: Anthropogenic disturbance of old-growth tropical forests increases the abundance of early successional tree species at the cost of late successional ones. Quantifying differences in terms of carbon allocation and the proportion of recently fixed carbon in soil CO2 efflux is crucial for addressing the carbon footprint of creeping degradation. Methodology: We compared the carbon allocation pattern of the late successional gymnosperm Podocarpus falcatus (Thunb.) Mirb. and the early successional (gap filling) angiosperm Croton macrostachyus Hochst. es Del. in an Ethiopian Afromontane forest by whole tree (CO2)-C-13 pulse labeling. Over a one-year period we monitored the temporal resolution of the label in the foliage, the phloem sap, the arbuscular mycorrhiza, and in soil-derived CO2. Further, we quantified the overall losses of assimilated C-13 with soil CO2 efflux. Principal Findings: C-13 in leaves of C. macrostachyus declined more rapidly with a larger size of a fast pool (64% vs. 50% of the assimilated carbon), having a shorter mean residence time (14 h vs. 55 h) as in leaves of P. falcatus. Phloem sap velocity was about 4 times higher for C. macrostachyus. Likewise, the label appeared earlier in the arbuscular mycorrhiza of C. macrostachyus and in the soil CO2 efflux as in case of P. falcatus (24 h vs. 72 h). Within one year soil CO2 efflux amounted to a loss of 32% of assimilated carbon for the gap filling tree and to 15% for the late successional one. Conclusions: Our results showed clear differences in carbon allocation patterns between tree species, although we caution that this experiment was unreplicated. A shift in tree species composition of tropical montane forests (e. g., by degradation) accelerates carbon allocation belowground and increases respiratory carbon losses by the autotrophic community. If ongoing disturbance keeps early successional species in dominance, the larger allocation to fast cycling compartments may deplete soil organic carbon in the long run.

Dette publique, développement monétaire international et demande de monnaie : une analyse à partir des tests de cointégration et du modèle à correction d'erreurs

Résumé : Ce document examine l'effet de la dette publique et du développement monétaire étranger (taux de change et taux d'intérêt étranger) sur la demande de monnaie de long-terme. Le déficit budgétaire est utilisé comme mesure de la dette publique. Cette étude est menée sur cinq pays industrialisés: le Canada, les États-Unis, l'Allemagne, le Royaume-Uni et la France. Le modèle multivarié de cointégration de Johansen & Juselius (1990) est utilisé pour établir le lien entre ces trois variables et la demande de monnaie. Ce modèle examine indirectement deux effets: les effets du déficit budgétaire sur le taux d'intérêt et du développement monétaire étranger sur le taux d'intérêt, à travers la demande de monnaie. L'évidence d'une relation de cointégration entre la demande de monnaie et les dites variables est vérifiée pour la plupart de ces pays. Le test d'exclusion des variables de la relation de long-terme nous révèle que toutes ces variables entrent de façon significative dans la relation de cointégration. Ces résultats suggèrent donc aux autorités monétaires, l'importance de tenir compte à la fois du déficit bugétaire et du développement monétaire étranger dans la formulation de la politique monétaire.||Abstract : This paper examines the impact of both public debt and foreign monetary developments (exchange rate and interest rate) on the long-run money demand. The budget déficit is used as a measure of public debt. Five industrial countries are considered, Canada, the United States, Germany, the United Kingdom and France. The multivariate cointegration model of Johansen & Juselius (1990) is used to establish the relationship between this tree variables and the money demand. This model indirectly examines two effects, the effect of budget déficits on interest rates and the effect of foreign monetary developments on the interest rates, both through money demand. Evidence of long-run relationship between the money demand and the defined variables are found for almost every country. The long-run exclusion test shows that ail these variables significantly enter into the cointegration relation. This suggests that, in formulating monetary policies, policy makers should take into account the influence of both budget déficit and foreign monetary developments on the money demand.

Unusual antibiotic presence in gym trained subjects with food intolerance: a case report

Introduction: Great interest is raising in food intolerances due to the lack, in many cases, of a particular sensitizing agent. Objective: We investigated the serum level of possible new haptens in 15 heavy meat consumers for sport fitness affected by various kinds of food intolerance and who had ever been administered antibiotics in their life for clinical problems. Methods: Forty ml of blood were drawn from each patient and analyzed, by means of an ELISA test, in order to possibly identify the presence of an undue contaminant with hapten properties. Results: Four out of fifteen subjects (26%) showed a serum oxytetracycline amount > 6 ng/g (which is considered the safety limit), 10 of 15 (66%) a serum doxycycline amount > of 6 ng/g and 3 out of 15 (30%) subjects had high serum level of both molecules. Conclusions: Although a direct ratio between body antibiotics remnant storage in the long run and chronic gut dysfunctions and/or food allergy did not reached the evidence yet, the blood traces of these compounds in a food intolerant otherwise healthy population might be considered the preliminary putative step of a sensitizing pathway. Our next goals foresee a deeper insight into the sensitizing trigger from human chronic antibiotic exposure via the zootechnical delivery of poultry food.

Neutrophil Chemotaxis in Multiple Chemoattractant Gradients

Chemotaxis, the phenomenon in which cells move in response to extracellular chemical gradients, plays a prominent role in the mammalian immune response. During this process, a number of chemical signals, called chemoattractants, are produced at or proximal to sites of infection and diffuse into the surrounding tissue. Immune cells sense these chemoattractants and move in the direction where their concentration is greatest, thereby locating the source of attractants and their associated targets. Leading the assault against new infections is a specialized class of leukocytes (white blood cells) known as neutrophils, which normally circulate in the bloodstream. Upon activation, these cells emigrate out of the vasculature and navigate through interstitial tissues toward target sites. There they phagocytose bacteria and release a number of proteases and reactive oxygen intermediates with antimicrobial activity. Neutrophils recruited by infected tissue in vivo are likely confronted by complex chemical environments consisting of a number of different chemoattractant species. These signals may include end target chemicals produced in the vicinity of the infectious agents, and endogenous chemicals released by local host tissues during the inflammatory response. To successfully locate their pathogenic targets within these chemically diverse and heterogeneous settings, activated neutrophils must be capable of distinguishing between the different signals and employing some sort of logic to prioritize among them. This ability to simultaneously process and interpret mulitple signals is thought to be essential for efficient navigation of the cells to target areas. In particular, aberrant cell signaling and defects in this functionality are known to contribute to medical conditions such as chronic inflammation, asthma and rheumatoid arthritis. To elucidate the biomolecular mechanisms underlying the neutrophil response to different chemoattractants, a number of efforts have been made toward understanding how cells respond to different combinations of chemicals. Most notably, recent investigations have shown that in the presence of both end target and endogenous chemoattractant variants, the cells migrate preferentially toward the former type, even in very low relative concentrations of the latter. Interestingly, however, when the cells are exposed to two different endogenous chemical species, they exhibit a combinatorial response in which distant sources are favored over proximal sources. Some additional results also suggest that cells located between two endogenous chemoattractant sources will respond to the vectorial sum of the combined gradients. In the long run, this peculiar behavior could result in oscillatory cell trajectories between the two sources. To further explore the significance of these and other observations, particularly in the context of physiological conditions, we introduce in this work a simplified phenomenological model of neutrophil chemotaxis. In particular, this model incorporates a trait commonly known as directional persistence - the tendency for migrating neutrophils to continue moving in the same direction (much like momentum) - while also accounting for the dose-response characteristics of cells to different chemical species. Simulations based on this model suggest that the efficiency of cell migration in complex chemical environments depends significantly on the degree of directional persistence. In particular, with appropriate values for this parameter, cells can improve their odds of locating end targets by drifting through a network of attractant sources in a loosely-guided fashion. This corroborates the prediction that neutrophils randomly migrate from one chemoattractant source to the next while searching for their end targets. These cells may thus use persistence as a general mechanism to avoid being trapped near sources of endogenous chemoattractants - the mathematical analogue of local maxima in a global optimization problem. Moreover, this general foraging strategy may apply to other biological processes involving multiple signals and long-range navigation.

Uma análise da política econômica a partir do desempenho da indústria automotiva brasileira no cenário econômico de 2003-2014

Entre 2003 e 2008, o Brasil apresentou um positivo desempenho econômico em meio a um cenário externo favorável, entretanto a partir da crise de 2008, o governo brasileiro passou a adotar medidas anticíclicas a fim de minimizar os efeitos externos da crise. Essas medidas objetivaram o incentivo da demanda agregada, o que realmente sofreu um efeito positivo de curto prazo, entretanto essas políticas, além de apresentar uma natureza limitada, podem levar a cenários futuros indesejados para o desenvolvimento econômico, como o aumento da inadimplência e taxa elevadas de inflação. Somado a isso, as medidas de incentivos de inovação e de desenvolvimento tecnológico foram interrompidas pela crise ou não implementadas de forma efetiva. Diante disto, a monografia se propõe a analisar os efeitos dessas políticas de incentivo à demanda adotada no período a partir de uma análise da indústria automotiva brasileira, uma das indústrias mais poderosas e receptoras de incentivos governamentais, já que apresenta um caráter dinâmico e movimenta um grande número de indústrias de base. Logo, para que a indústria automotiva cresça e se desenvolva de forma sustentável, bem como os outros setores, o incentivo não deve ser de cunho setorial, por tanto, temporário, deve ser de natureza permanente e abrangente. Além disso, um incentivo da demanda terá resultados positivos com os incentivos tecnológicos, inovadores e de qualificação do capital humano para uma crescente exportação, levando a saldos positivos da balança comercial e, consequentemente, maiores investimentos a partir de uma indústria mais competitiva.

Empirical studies on share issuance and repurchase decisions

Financial constraints influence corporate policies of firms, including both investment decisions and external financing policies. The relevance of this phenomenon has become more pronounced during and after the recent financial crisis in 2007/2008. In addition to raising costs of external financing, the effects of financial crisis limited the availability of external financing which had implications for employment, investment, sale of assets, and tech spending. This thesis provides a comprehensive analysis of the effects of financial constraints on share issuance and repurchases decisions. Financial constraints comprise both internal constraints reflecting the demand for external financing and external financial constraints that relate to the supply of external financing. The study also examines both operating performance and stock market reactions associated with equity issuance methods. The first empirical chapter explores the simultaneous effects of financial constraints and market timing on share issuance decisions. Internal financing constraints limit firms’ ability to issue overvalued equity. On the other hand, financial crisis and low market liquidity (external financial constraints) restrict availability of equity financing and consequently increase the costs of external financing. Therefore, the study explores the extent to which internal and external financing constraints limit market timing of equity issues. This study finds that financial constraints play a significant role in whether firms time their equity issues when the shares are overvalued. The conclusion is that financially constrained firms issue overvalued equity when the external equity market or the general economic conditions are favourable. During recessionary periods, costs of external finance increase such that financially constrained firms are less likely to issue overvalued equity. Only unconstrained firms are more likely to issue overvalued equity even during crisis. Similarly, small firms that need cash flows to finance growth projects are less likely to access external equity financing during period of significant economic recessions. Moreover, constrained firms have low average stock returns compared to unconstrained firms, especially when they issue overvalued equity. The second chapter examines the operating performance and stock returns associated with equity issuance methods. Firms in the UK can issue equity through rights issues, open offers, and private placement. This study argues that alternative equity issuance methods are associated with a different level of operating performance and long-term stock returns. Firms using private placement are associated with poor operating performance. However, rights issues are found empirically to be associated with higher operating performance and less negative long-term stock returns after issuance in comparison to counterpart firms that issue private placements and open offers. Thus, rights issuing firms perform better than open offers and private placement because the favourable operating performance at the time of issuance generates subsequent positive long-run stock price response. Right issuing firms are of better quality and outperform firms that adopt open offers and private placement. In the third empirical chapter, the study explores the levered share repurchase of internally financially unconstrained firms. Unconstrained firms are expected to repurchase their shares using internal funds rather than through external borrowings. However, evidence shows that levered share repurchases are common among unconstrained firms. These firms display this repurchase behaviour when they have bond ratings or investment grade ratings that allow them to obtain cheap external debt financing. It is found that internally financially unconstrained firms borrow to finance their share repurchase when they invest more. Levered repurchase firms are associated with less positive abnormal returns than unlevered repurchase firms. For the levered repurchase sample, high investing firms are associated with more positive long-run abnormal stock returns than low investing firms. It appears the market underreact to the levered repurchase in the short-run regardless of the level of investments. These findings indicate that market reactions reflect both undervaluation and signaling hypotheses of positive information associated with share repurchase. As the firms undertake capital investments, they generate future cash flows, limit the effects of leverage on financial distress and ultimately reduce the risk of the equity capital.

Verhaltens- und fertigkeitenbasierte Frühinterventionen bei Kindern mit Autismus

Einleitung: Zu den autistischen Syndromen werden der frühkindliche Autismus (Kanner-Syndrom), das Asperger-Syndrom und atypische Autismusformen oder nicht-spezifizierte tiefgreifende Entwicklungsstörungen gezählt. Bei den autistischen Syndromen liegen Beeinträchtigungen (1) der Kommunikation und (2) der sozialen Interaktion vor. Weiterhin weisen (3) die Kinder in unterschiedlichem Maß stereotypes, repetitives Verhalten auf und haben bestimmte Sonderinteressen. Verhaltensbasierte Frühinterventionen bei Kindern mit Autismus basieren auf lerntheoretischen und verhaltenstherapeutischen Konzepten. Sie berücksichtigen die besonderen vorliegenden Beeinträchtigungen in der Wahrnehmung, der emotionalen Reaktionen, der sozialen Interaktionen sowie der Kommunikationsmuster. Die systematische Anwendung und Evaluation solcher Modelle in Deutschland ist aber bisher eher die Ausnahme. Fragestellungen: - Wie sind die gesundheitliche Effektivität und Sicherheit von verhaltens- oder fertigkeitenbasierten Frühinterventionen bei autistischen Syndromen untereinander und verglichen mit einer Standardbehandlung? - Gibt es Hinweise auf besondere Wirkfaktoren für die Effektivität? - Wie ist die Kosten-Effektivität? - Wie hoch sind die Kosten der verschiedenen Interventionen? - Lassen sich aus ethischen und rechtlichen Überlegungen Schlüsse für die Anwendung der betrachteten Interventionen bei Betroffenen mit autistischem Syndrom in der Praxis ziehen? Methoden: Basierend auf einer systematischen Literaturrecherche werden ab 2000 in deutscher oder englischer Sprache veröffentlichte kontrollierte Studien zu verhaltens- oder fertigkeitenbasierten Frühinterventionen bei Kindern mit Autismus im Alter von bis zu zwölf Jahren eingeschlossen und bewertet. Die Mindestzahl an Studienteilnehmern muss zehn pro Interventionsgruppe betragen. Ergebnisse: Insgesamt 15 Veröffentlichungen klinischer Primärstudien, acht systematische Reviews und eine ökonomische Veröffentlichung erfüllen die Einschlusskriterien. Die meisten Studien evaluieren intensive Frühinterventionen, die sich an das Modell von Lovaas (Early intensive behavioural treatment (EIBT), Applied behavioural analysis (ABA)) anlehnen. Einige Studien evaluieren andere Interventionen, die teilweise pragmatisch waren und teilweise einem bestimmten Modell folgen (spezifisches Elterntraining, Responsive education and prelinguistic milieu teaching (RPMT), Joint attention (JA) und symbolisches Spielen (SP), Picture exchange communication system (PECS)). Verhaltensanalytische Interventionen basierend auf dem Lovaas-Modell können weiterhin als die am besten empirisch abgesicherten Frühinterventionen angesehen werden. Vorschulkinder mit Autismus können durch verhaltensbasierte Interventionen mit einer Mindestintensität von 20 Stunden pro Woche Verbesserungen in kognitiven und funktionalen Bereichen (expressive Sprache, Sprachverständnis und Kommunikation) erreichen. Es bleibt jedoch unklar, welche Mindestintensität notwendig ist, und welche Wirkkomponenten für die Ergebnisse verantwortlich sind. Für andere umfassende Frühinterventionen bei Kindern mit Autismus liegt keine hochwertige Evidenz vor. Die für den ökonomischen Teilbereich identifizierte und einbezogene Publikation ist methodisch und thematisch nicht dazu geeignet, die Fragen nach der Kosten-Effektivität oder den Kostenwirkungen von Frühinterventionen beim Autismus auch nur ansatzweise zu beantworten. Publikationen zu rechtlichen, ethischen oder sozialen Aspekten werden nicht identifiziert. Die finanzielle Lage der Betroffenen und der Familien wird durch das Pflege-Weiterentwicklungsgesetz (Pf-WG) verbessert. Weitere rechtliche Belange betreffen die Betreuung und die Deliktfähigkeit der Menschen mit Autismus. Auch die gleichheitliche Betreuung und Versorgung sind insbesondere vor dem Hintergrund der Pflege im häuslichen Umfeld eine wichtige Frage. Diskussion: Es gibt nur wenige methodisch angemessene Studien zur Beurteilung der Wirksamkeit von Frühinterventionen bei Kindern mit Autismus. Die meisten Studien sind vergleichsweise kurz und haben teilsweise kein verblindetes Ergebnis-Rating. Der Mangel an hochwertigen vergleichenden Studien lässt keine solide Antwort auf die Frage zu, welche Frühintervention bei welchen Kindern mit Autismus am wirksamsten ist. Programme nach dem Lovaas-Modell scheinen am wirkungsvollsten zu sein. Dies gilt vor allem, wenn sie klinikbasiert durchgeführt werden. Zu einzelnen Wirkfaktoren von Frühinterventionen nach dem ABA-Modell konnte allerdings keine solide Evidenz gefunden werden. Es zeigte sich, dass ein Elterntraining hinsichtlich der Verbesserung der Kommunikation besser ist als eine Routinebehandlung, in der eine Mischung von Theapieelementen angewendet wird. Sowohl für die klinischen als auch die gesundheitsökonomischen Studien besteht das Problem unzureichender Verallgemeinerbarkeit der Studienergebnisse in den deutschen Versorgungskontext. Die ökonomischen Studien sind methodisch und thematisch nicht dazu geeignet die aufgeworfenen Fragestellungen zu beantworten. Schlussfolgerung: Basierend auf der derzeitigen Studienlage liegt für keine der untersuchten verhaltensbasierten Frühinterventionen bei Kindern mit Autismus ausreichende Evidenz vor. Die in diesem Bericht ausgewerteten Studien und Reviews legen nahe, dass Vorschulkinder mit Autismus durch verhaltensbasierte Interventionen mit einer Mindestintensität von 20 Stunden pro Woche Verbesserungen in kognitiven und funktionalen Bereichen erreichen können. Es gibt bisher keine Hinweise, dass bei einem substantiellen Anteil der Kinder eine vollständige Normalisierung der Entwicklung erreicht werden kann. Die meiste Evidenz liegt für die ABA vor. Ein Minimum an erforderlicher oder sinnvoller Behandlungsintensität kann jedoch nicht angegeben werden. Eine professionelle Umsetzung eines verhaltensbasierten Frühinterventionsprogrammes in engem und ausführlichem Kontakt mit den Kindern und unter Einbeziehung der Eltern erscheint sinnvoll. Zur Kosten-Effektivität von intensiven Frühinterventionen bei Kindern mit Autismus können keine validen Angaben gemacht werden. Effektive Frühinterventionen könnten jedoch die Gesamtkosten des Autismus langfristig reduzieren, indem die anfallenden hohen Aufwendungen durch eine spätere bessere soziale Anpassung überkompensiert werden.