Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XV. Long-Term Optical Monitoring of NGC 5548

We present the results of three years of ground-based observations of the Seyfert 1 galaxy NGC 5548, which combined with previously reported data, yield optical continuum and broad-line H-beta light curves for a total of eight years. The light curves consist of over 800 points, with a typical spacing of a few days between observations. During this eight-year period, the nuclear continuum has varied by more than a factor of seven, and the H-beta emission line has varied by a factor of nearly six. The H-beta emission line responds to continuum variations with a time delay or lag of 10-20 days, the precise value varying somewhat from year to year. We find some indications that the lag varies with continuum flux in the sense that the lag is larger when the source is brighter.Comment: 29 pages, 6 figures. Accepted for publication in ApJ (1999 Jan 10

Learned vocal variation is associated with abrupt cryptic genetic change in a parrot species complex

<div><p>Contact zones between subspecies or closely related species offer valuable insights into speciation processes. A typical feature of such zones is the presence of clinal variation in multiple traits. The nature of these traits and the concordance among clines are expected to influence whether and how quickly speciation will proceed. Learned signals, such as vocalizations in species having vocal learning (e.g. humans, many birds, bats and cetaceans), can exhibit rapid change and may accelerate reproductive isolation between populations. Therefore, particularly strong concordance among clines in learned signals and population genetic structure may be expected, even among continuous populations in the early stages of speciation. However, empirical evidence for this pattern is often limited because differences in vocalisations between populations are driven by habitat differences or have evolved in allopatry. We tested for this pattern in a unique system where we may be able to separate effects of habitat and evolutionary history. We studied geographic variation in the vocalizations of the crimson rosella (<em>Platycercus elegans</em>) parrot species complex. Parrots are well known for their life-long vocal learning and cognitive abilities. We analysed contact calls across a <em>ca</em> 1300 km transect encompassing populations that differed in neutral genetic markers and plumage colour. We found steep clinal changes in two acoustic variables (fundamental frequency and peak frequency position). The positions of the two clines in vocal traits were concordant with a steep cline in microsatellite-based genetic variation, but were discordant with the steep clines in mtDNA, plumage and habitat. Our study provides new evidence that vocal variation, in a species with vocal learning, can coincide with areas of restricted gene flow across geographically continuous populations. Our results suggest that traits that evolve culturally can be strongly associated with reduced gene flow between populations, and therefore may promote speciation, even in the absence of other barriers.</p> </div

A scoring system to predict renal outcome in IgA nephropathy: a nationwide 10-year prospective cohort study

Background. Immunoglobulin A nephropathy (IgAN) is the most common form of glomerulonephritis, and a substantial number of patients succumb to end-stage renal disease (ESRD). However, prediction of the renal outcome in individual patients remains difficult. We have already published a scoring system using the data in a prospective cohort of IgAN patients followed up from 1995 to 2002

Evolutionary Views on Entrepreneurial Processes: Managerial and Policy Implications

In this paper we outline an evolutionary framework of entrepreneurial processes where by firms are started, grow, and exit from the market. We explain the important of such a framework in explaining both what contextual factor affects entrepreneurial processes and in explaining the distinction and interaction between self-employment and high-potential entrepreneurship. We highlight the implications from prior empirical work using this evolutionary framework for management and policy making: Three broad implications relevant for managers and entrepreneurs interested in understanding how they can leverage their chances to position their firms as ripe for growth, and six detailed implications relevant for policy makers interested in understanding and affecting the structural conditions where by entrepreneurship can lead to enhanced growth and job creation

Mechanisms of progression of chronic kidney disease

Chronic kidney disease (CKD) occurs in all age groups, including children. Regardless of the underlying cause, CKD is characterized by progressive scarring that ultimately affects all structures of the kidney. The relentless progression of CKD is postulated to result from a self-perpetuating vicious cycle of fibrosis activated after initial injury. We will review possible mechanisms of progressive renal damage, including systemic and glomerular hypertension, various cytokines and growth factors, with special emphasis on the renin–angiotensin–aldosterone system (RAAS), podocyte loss, dyslipidemia and proteinuria. We will also discuss possible specific mechanisms of tubulointerstitial fibrosis that are not dependent on glomerulosclerosis, and possible underlying predispositions for CKD, such as genetic factors and low nephron number

Kentucky Breweries and Local Identity

Local breweries in Kentucky attract those who identify with the local community. In general, residents near a brewery are more likely to drink the local beer, because they feel they are contributing to a place that shapes their identity. Research shows that breweries often use this local identity to sell their product, using local items in their brewery to draw visitors. This project determined the local identity of Kentucky brewery visitors and their attachment to the local community, and the results showed that people have a stronger local identity when they drink local beer. Additionally, local brewery patrons believed that local beer is more environmentally friendly and healthier. It is also believed that local beer has a better taste and many prefer local beer over the widely manufactured beer. In conclusion, the local community feels that these breweries contribute to the local identity of the community. While more research can help understand patron preferences, results may help brewery and local business marketing and promotion by linking products to local identity.https://encompass.eku.edu/swps_undergraduategallery/1149/thumbnail.jp