On the Poisson Process of Order k Space

2010 Mathematics Subject Classification: 60E05, 62P05.

Does start-up financing influence start-up speed? Evidence from the panel study of entrepreneurial dynamics

Why are some entrepreneurs able to start a new firm more quickly than others in the venture creation process? Drawing on pecking order and agency theory, this study investigates how start-up capital structure influences the time to either new firm founding or quitting the start-up process. The temporal aspect of the start-up process is one that is often discussed, but rarely studied. Therefore, we utilize competing risk and Cox regression event history analysis on a nationally representative sample of US entrepreneurs to investigate how start-up capital structure impacts the time in gestation to particular kinds of start-up outcomes. Our findings suggest that external equity has an appreciable impact on new firm emergence over time, and that the percentage of ownership held by the founders attenuates the benefits of external equity.

A közalkalmazotti béremelés hatása a tanárok pályaelhagyási döntéseire (The effect of a public-sector pay increase on teachers attrition)

A tanárok pályaelhagyási döntését vizsgálva, a tanulmány a következő két kérdésre keresi a választ. Milyen szerepet játszanak e döntésekben a keresetek, alternatív kereseti lehetőségek? Hogyan hatott a tanárok pályaelhagyására a 2002. évi közalkalmazotti béremelés? Az elemzéshez az OEP-ONYF-FH összekapcsolt nagymintás adatbázis felhasználásával kétféle modellt becsült a szerző: 1. két lehetőséget megkülönböztetve (elhagyja a tanári pályát/nem hagyja el) Cox-féle arányos hazárdfüggvényeket, 2. a pályaelhagyás okai között a más állásba kerülést és az egyéb pályaelhagyási okokat megkülönböztetve versengő kockázati modelleket. Az eredmények azt mutatják, hogy a kereseti lehetőségek hatnak a pályaelhagyási döntésekre. A magasabb jövedelem és magasabb relatív kereset csökkenti annak valószínűségét, hogy egy tanár elhagyja a pályát, és más pályán helyezkedjen el, vagy nem foglalkoztatotti státusba kerüljön. A közalkalmazotti béremelés átmenetileg csökkentette a pályaelhagyás valószínűségét a fiatal tanárok körében, de a hatás egy-két év alatt eltűnt. Az 51 évesnél idősebb tanárokat pedig inkább a pályán tartotta a béremelés, csökkentette annak valószínűségét is, hogy más pályán helyezkedjenek el, vagy hogy nem foglalkoztatotti státusba kerüljenek. ______ The paper investigates teachers decisions to leave the profession. It first examines the role in such decisions of pay compared with earnings in alternative occupations, and then discusses how the public-sector pay increase of 2002 af-fected exit decisions by teachers. Duration models were estimated using large merged administrative data sets. First binary-choice Cox proportional hazard models (leaving teaching profession or not), then competing risk models that distinguish exits to another occupation and exits to a non-working state. Results show that earnings matter. Higher wages reduce the probability of exiting teacher profession to go to another occupation or to non-employment. The public-sector pay increase decreased the probability of inexperienced teachers leaving the teacher profession temporarily, but the effect disappeared after one or two years. For experienced teachers over 51 years old, the wage increase was found to reduce attrition.

Essays in Macro Finance

I study the link between capital markets and sources of macroeconomic risk. In chapter 1 I show that expected inflation risk is priced in the cross section of stock returns even after controlling for cash flow growth and volatility risks. Motivated by this evidence I study a long run risk model with a built-in inflation non-neutrality channel that allows me to decompose the real stochastic discount factor into news about current and expected cash flow growth, news about expected inflation and news about volatility. The model can successfully price a broad menu of assets and provides a setting for analyzing cross sectional variation in expected inflation risk premium. For industries like retail and durable goods inflation risk can account for nearly a third of the overall risk premium while the energy industry and a broad commodity index act like inflation hedges. Nominal bonds are exposed to expected inflation risk and have inflation premiums that increase with bond maturity. The price of expected inflation risk was very high during the 70's and 80's, but has come down a lot since being very close to zero over the past decade. On average, the expected inflation price of risk is negative, consistent with the view that periods of high inflation represent a "bad" state of the world and are associated with low economic growth and poor stock market performance. In chapter 2 I look at the way capital markets react to predetermined macroeconomic announcements. I document significantly higher excess returns on the US stock market on macro release dates as compared to days when no macroeconomic news hit the market. Almost the entire equity premium since 1997 is being realized on days when macroeconomic news are released. At high frequency, there is a pattern of returns increasing in the hours prior to the pre-determined announcement time, peaking around the time of the announcement and dropping thereafter.

Cultura e clima organizacionais: um estudo multicasos em indústrias de laticínios do estado do Rio Grande do Norte

The objective of this study is to investigate if exist relationship between organizational culture and the organizational climate, having as research s locus three dairy industries in the Rio Grande do Norte State. As such, an exploratory-descriptive and conclusive-causal study, with a sample composed of 211 employees of all firms hierarchical levels was undertaken. By way the data collection, the employees personal characteristics, the predominant organizational culture profile and the predominant organizational climate in the industries researched were identified. In order to analyse the organizational culture, the Competing Value Model (CAMERON; QUINN, 2006), with adaptations by Santos (1998, 2000), was used. In order to analyse the organizational climate, the Organizational Climate Measurement Scale, proposed by Martins (et al., 2004, 2008), with modifications, was used. The data were submitted to quantitative statistical analyses, firstly to the set of firms and afterwards to the firms alone, that permitted arrival to the following conclusions: the cultural profiles was met in a balanced way in the researched organizations, with emphasis to clan culture and market culture profiles; the researched organizations have a good organizational climate, based in the Martins (2008) classification, with emphasis to boss and organization s support and physical comfort , being these factors coherent whit the clan culture profile; the personal variables are correlated with the cultural profiles and with the organizational climate factors, however, each organization show its singular form of relation; and the cultural profiles showed influence on organizational climate factors. Thus, the results permitted to conclude that there are relations between the cultural profiles and the organizational climate factors in the researched organizations

Estimation du paramètre d'une copule archimedienne en présence de censure dépendante

Les méthodes classiques d’analyse de survie notamment la méthode non paramétrique de Kaplan et Meier (1958) supposent l’indépendance entre les variables d’intérêt et de censure. Mais, cette hypothèse d’indépendance n’étant pas toujours soutenable, plusieurs auteurs ont élaboré des méthodes pour prendre en compte la dépendance. La plupart de ces méthodes émettent des hypothèses sur cette dépendance. Dans ce mémoire, nous avons proposé une méthode d’estimation de la dépendance en présence de censure dépendante qui utilise le copula-graphic estimator pour les copules archimédiennes (Rivest etWells, 2001) et suppose la connaissance de la distribution de la variable de censure. Nous avons ensuite étudié la consistance de cet estimateur à travers des simulations avant de l’appliquer sur un jeu de données réelles.

Metodología para la medición del riesgo de liquidez en una cooperativa financiera

Este trabajo plantea la implementación de una metodología para la medición del riego de liquidez al modelo interno adoptado por CONFIAR Cooperativa Financiera, haciendo énfasis en proyecciones estadísticas de los depósitos y retiros de cuentas de ahorro a la vista, depósitos y retiros de aportes sociales, captaciones en contratos de depósito a término, captaciones en depósitos contractuales y los desembolsos de créditos, a través del modelo de series de tiempo para la construcción del flujo de caja, conforme a lo exigido por la Superintendencia Financiera de Colombia.

Cultura e clima organizacionais: um estudo multicasos em indústrias de laticínios do estado do Rio Grande do Norte

The objective of this study is to investigate if exist relationship between organizational culture and the organizational climate, having as research s locus three dairy industries in the Rio Grande do Norte State. As such, an exploratory-descriptive and conclusive-causal study, with a sample composed of 211 employees of all firms hierarchical levels was undertaken. By way the data collection, the employees personal characteristics, the predominant organizational culture profile and the predominant organizational climate in the industries researched were identified. In order to analyse the organizational culture, the Competing Value Model (CAMERON; QUINN, 2006), with adaptations by Santos (1998, 2000), was used. In order to analyse the organizational climate, the Organizational Climate Measurement Scale, proposed by Martins (et al., 2004, 2008), with modifications, was used. The data were submitted to quantitative statistical analyses, firstly to the set of firms and afterwards to the firms alone, that permitted arrival to the following conclusions: the cultural profiles was met in a balanced way in the researched organizations, with emphasis to clan culture and market culture profiles; the researched organizations have a good organizational climate, based in the Martins (2008) classification, with emphasis to boss and organization s support and physical comfort , being these factors coherent whit the clan culture profile; the personal variables are correlated with the cultural profiles and with the organizational climate factors, however, each organization show its singular form of relation; and the cultural profiles showed influence on organizational climate factors. Thus, the results permitted to conclude that there are relations between the cultural profiles and the organizational climate factors in the researched organizations

ESR/ERS white paper on lung cancer screening

Lung cancer is the most frequently fatal cancer, with poor survival once the disease is advanced. Annual low-dose computed tomography has shown a survival benefit in screening individuals at high risk for lung cancer. Based on the available evidence, the European Society of Radiology and the European Respiratory Society recommend lung cancer screening in comprehensive, quality-assured, longitudinal programmes within a clinical trial or in routine clinical practice at certified multidisciplinary medical centres. Minimum requirements include: standardised operating procedures for low-dose image acquisition, computer-assisted nodule evaluation, and positive screening results and their management; inclusion/exclusion criteria; expectation management; and smoking cessation programmes. Further refinements are recommended to increase quality, outcome and cost-effectiveness of lung cancer screening: inclusion of risk models, reduction of effective radiation dose, computer-assisted volumetric measurements and assessment of comorbidities (chronic obstructive pulmonary disease and vascular calcification). All these requirements should be adjusted to the regional infrastructure and healthcare system, in order to exactly define eligibility using a risk model, nodule management and a quality assurance plan. The establishment of a central registry, including a biobank and an image bank, and preferably on a European level, is strongly encouraged. Key points: • Lung cancer screening using low dose computed tomography reduces mortality. • Leading US medical societies recommend large scale screening for high-risk individuals. • There are no lung cancer screening recommendations or reimbursed screening programmes in Europe as of yet. • The European Society of Radiology and the European Respiratory Society recommend lung cancer screening within a clinical trial or in routine clinical practice at certified multidisciplinary medical centres. • High risk, eligible individuals should be enrolled in comprehensive, quality-controlled longitudinal programmes.

Longitudinal outcomes of high-risk human papillomavirus (HPV) infections as competing-risks events following cervical HPV test at baseline visit in the *NIS-LAMS** cohort

Background: The complex natural history of human papillomavirus (HPV) infections following a single HPV test can be modeled as competing-risks events (i.e., no-, transient- or persistent infection) in a longitudinal setting. The covariates associated with these compet ng events have not been previously assessed using competing-risks regression models. Objectives: To gain further insights in the outcomes of cervical HPV infections, we used univariate- and multivariate competing-risks regression models to assess the covariaies associated with these competing events. Study Design and Methods: Covariates associated with three competing outcomes (no-, transient- or persistent HR-HPV infection) were analysed in a sub-cohort of 1,865 women prospectively followed-up in the NIS (n = 3,187) and LAMS Study (n = 12,114). Results: In multivariate competing-risks models (with two other outcomes as competing events), permanently HR-HPV negative outcome was significantly predicted only by the clearance of ASCUS+Pap during FU, while three independent covariates predicted transient HR-HPV infections: i) number of recent (< 12 months) sexual partners (risk increased), ii) previous Pap screening history (protective), and history of previous CIN (increased risk). The two most powerful predictors of persistent HR-HPV infections were persistent ASCUS+Pap (risk increased), and previous Pap screening history (protective). In pair-wise comparisons, number of recent sexual partners and previous CIN history increase the probability of transient HR-HPV infection against the HR-HPV negative competing event, while previous Pap screening history is protective. Persistent ASCUS+Pap during FU and no previous Pap screening history are significantly associated with the persistent HR-HPV outcome (compared both with i) always negative, and ii) transient events), whereas multiparity is protective. Conclusions: Different covariates are associated with the three main outcomes of cervical HPV infections. The most significant covariates of each competing events are probably distinct enough to enable constructing of a risk-profile for each main outcome.

Influence of a probiotic soy product on fecal microbiota and its association with cardiovascular risk factors in an animal model

Background: Previous work showed that daily ingestion of an aqueous soy extract fermented with Enterococcus faecium CRL 183 and Lactobacillus helveticus 416, supplemented or not with isoflavones, reduced the total cholesterol and non-HDL-cholesterol levels, increased the high-density lipoprotein (HDL) concentration and inhibited the raising of autoantibody against oxidized low-density lipoprotein (ox-LDL Ab) and the development of atherosclerotic lesions. Objective: The aim of this study was to characterize the fecal microbiota in order to investigate the possible correlation between fecal microbiota, serum lipid parameters and atherosclerotic lesion development in rabbits with induced hypercholesterolemia, that ingested the aqueous soy extract fermented with Enterococcus faecium CRL 183 and Lactobacillus helveticus 416. Methods: The rabbits were randomly allocated to five experimental groups (n = 6): control (C), hypercholesterolemic (H), hypercholesterolemic plus unfermented soy product (HUF), hypercholesterolemic plus fermented soy product (HF) and hypercholesterolemic plus isoflavone-supplemented fermented soy product (HIF). Lipid parameters and microbiota composition were analyzed on days 0 and 60 of the treatment and the atherosclerotic lesions were quantified at the end of the experiment. The fecal microbiota was characterized by enumerating the Lactobacillus spp., Bifidobacterium spp., Enterococcus spp., Enterobacteria and Clostridium spp. populations. Results: After 60 days of the experiment, intake of the probiotic soy product was correlated with significant increases (P < 0.05) on Lactobacillus spp., Bifidobacterium spp. and Enterococcus spp. and a decrease in the Enterobacteria population. A strong correlation was observed between microbiota composition and lipid profile. Populations of Enterococcus spp., Lactobacillus spp. and Bifidobacterium spp. were negatively correlated with total cholesterol, non-HDL-cholesterol, autoantibodies against oxidized LDL (ox-LDL Ab) and lesion size. HDL-C levels were positively correlated with Lactobacillus spp., Bifidobacterium spp., and Enterococcus spp. populations. Conclusion: In conclusion, daily ingestion of the probiotic soy product, supplemented or not with isoflavones, may contribute to a beneficial balance of the fecal microbiota and this modulation is associated with an improved cholesterol profile and inhibition of atherosclerotic lesion development.

On modifications to the long-term survival mixture model in the presence of competing risks

A mixture model for long-term survivors has been adopted in various fields such as biostatistics and criminology where some individuals may never experience the type of failure under study. It is directly applicable in situations where the only information available from follow-up on individuals who will never experience this type of failure is in the form of censored observations. In this paper, we consider a modification to the model so that it still applies in the case where during the follow-up period it becomes known that an individual will never experience failure from the cause of interest. Unless a model allows for this additional information, a consistent survival analysis will not be obtained. A partial maximum likelihood (ML) approach is proposed that preserves the simplicity of the long-term survival mixture model and provides consistent estimators of the quantities of interest. Some simulation experiments are performed to assess the efficiency of the partial ML approach relative to the full ML approach for survival in the presence of competing risks.

A model for predicting the future incidence of coronary heart disease within percentiles of coronary heart disease risk

Background We present a method (The CHD Prevention Model) for modelling the incidence of fatal and nonfatal coronary heart disease (CHD) within various CHD risk percentiles of an adult population. The model provides a relatively simple tool for lifetime risk prediction for subgroups within a population. It allows an estimation of the absolute primary CHD risk in different populations and will help identify subgroups of the adult population where primary CHD prevention is most appropriate and cost-effective. Methods The CHD risk distribution within the Australian population was modelled, based on the prevalence of CHD risk, individual estimates of integrated CHD risk, and current CHD mortality rates. Predicted incidence of first fatal and nonfatal myocardial infarction within CHD risk strata of the Australian population was determined. Results Approximately 25% of CHD deaths were predicted to occur amongst those in the top 10 percentiles of integrated CHD risk, regardless of age group or gender. It was found that while all causes survival did not differ markedly between percentiles of CHD risk before the ages of around 50-60, event-free survival began visibly to differ about 5 years earlier. Conclusions The CHD Prevention Model provides a means of predicting future CHD incidence amongst various strata of integrated CHD risk within an adult population. It has significant application both in individual risk counselling and in the identification of subgroups of the population where drug therapy to reduce CHD risk is most cost-effective. J Cardiovasc Risk 8:31-37 (C) 2001 Lippincott Williams & Wilkins.