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Cyclical Variations (cyclical + variation)
Selected AbstractsInflow Composition, Duration Dependence and their Impact on the Unemployment Outflow Rate*OXFORD BULLETIN OF ECONOMICS & STATISTICS, Issue 1 2003Hélène Turon This paper presents estimates of the components of the dynamics of the unemployment outflow rate with British data. We allow both the composition of the inflow and individual duration dependence to vary over the business cycle. We find the inflow composition to be strongly countercyclical. Individual exit rates are found to be substatntially more sensitive to the business cycle than previously thought and than the average exit rate fluctuations suggest. Cyclical variations in duration dependence are not significant. With our estimates, fluctuations in the average exit rate out of the first year of unemployment are mainly accounted for by variations of individual exit rates, variation of inflow composition, and variation in the inflow level combined with the duration dependence phenomenon. [source] Pulsed resources affect the timing of first breeding and lifetime reproductive success of tawny owlsJOURNAL OF ANIMAL ECOLOGY, Issue 2 2010A. Millon Summary 1.,According to life-history theory, environmental variability and costs of reproduction account for the prevalence of delayed reproduction in many taxa. Empirical estimates of the fitness consequences of different ages at first breeding in a variable environment are few however such that the contributions of environmental and individual variability remains poorly known. 2.,Our objectives were to elucidate processes that underpin variation in delayed reproduction and to assess lifetime consequences of the age of first breeding in a site-faithful predator, the tawny owl Strix aluco L. subjected to fluctuating selection linked to cyclical variation in vole density (typically 3-year cycles with low, increasing and decreasing vole densities in successive years). 3.,A multistate capture,recapture model revealed that owl cohorts had strikingly different juvenile survival prospects, with estimates ranging from 0·08 to 0·33 respectively for birds born in Decrease and Increase phases of the vole cycle. This resulted in a highly skewed population structure with >75% of local recruits being reared during Increase years. In contrast, adult survival remained constant throughout a vole cycle. The probability of commencing reproduction was lower at age 1 than at older ages, and especially so for females. From age 2 onwards, pre-breeders had high probabilities of entering the breeding population. 4.,Variation in lifetime reproductive success was driven by the phase of the vole cycle in which female owls started their breeding career (26,47% of variance explained, whether based on the number of local recruits or fledglings), more than by age at first breeding or by conditions experienced at birth. Females who postponed reproduction to breed for the first time at age 3 during an Increase phase, produced more recruits, even when accounting for birds that may have died before reproduction. No such effects were detected for males. 5.,Sex-specific costs of early reproduction may have accounted for females being more prone to delay reproduction. Contrary to expectations from a best-of-a-bad job strategy, early-hatched, hence potentially higher-quality females were more likely to breed at age 1, but then experienced rapidly declining food resources and so seemed caught in a life-history trap set by the multiannual vole cycle. [source] Political and Regulatory Risk in Water Utilities: Beta Sensitivity in the United KingdomJOURNAL OF BUSINESS FINANCE & ACCOUNTING, Issue 7-8 2001Roger Buckland UK utilities are generally regulated by the periodic setting of a price cap (the RPI-X mechanism). To establish these caps, regulators must determine what returns are appropriate on the capital employed by utilities. This paper addresses the issue of the level of risk inherent in investment in the equity of regulated water utilities in the UK. It uses the techniques of the Kalman Filter to estimate daily betas for the major utilities in the period from privatisation to mid-1999. The paper demonstrates that water utilities' risk is time-variant. It demonstrates, also, that there have been significant political and regulatory influences in the systematic risk faced by water utility shareholders. It finds beta to display little evidence of cyclical variation across the regulatory review cycle. The paper also confirms that significant excess returns have been generated over the history of the privatised water sector and suggests that over-estimation of systematic risk faced by investors in the sector may imply further excess returns in the next regulatory review period. [source] Disability, capacity for work and the business cycle: an international perspectiveECONOMIC POLICY, Issue 63 2010Hugo Benítez-Silva Summary Important policy issues arise from the high and growing number of people claiming disability benefits for reasons of incapacity for work in OECD countries. Economic conditions play an important part in explaining both the stock of disability benefit claimants and inflows to and outflows from that stock. Employing a variety of cross-country and country-specific household panel data sets, as well as administrative data, we find strong evidence that local variations in unemployment have an important explanatory role for disability benefit receipt, with higher total enrolments, lower outflows from rolls and, often, higher inflows into disability rolls in regions and periods of above-average unemployment. In understanding the nature of the cyclical fluctuations and trends in disability it is important to distinguish between work disability and health disability. The former is likely to be influenced by economic conditions and welfare programmes while the latter evolves in a slower fashion with medical technology and demographic changes. There is little evidence of health disability being related to the business cycle, so cyclical variations are driven by work disability. The rise in unemployment due to the current global economic crisis is expected to increase the number of disability insurance claimants. --- Hugo Benítez-Silva, Richard Disney and Sergi Jiménez-Martín [source] Seasonal variation of enteric infections and inflammatory bowel diseaseINFLAMMATORY BOWEL DISEASES, Issue 7 2008Amnon Sonnenberg MD Abstract Background: The time trends of inflammatory bowel disease are characterized by short-term variations that affect Crohn's disease and ulcerative colitis alike. The aim of the present study was to test whether these variations might be related to exacerbations of inflammatory bowel disease secondary to superimposed gastrointestinal infection. Methods: The Hospital Episode Statistics (HES) comprises a data set of all patients admitted to hospitals throughout England, which includes inpatients and day cases. This data set was used to analyze the monthly variations in all hospital admissions for Crohn's disease (ICD10 code K50), ulcerative colitis (K51), bacterial intestinal infections (A04), viral intestinal infections (A08), diarrhea and infectious gastroenteritis (A09), upper respiratory infections (J06), pneumonia secondary to unspecified organism (J18), and unspecified acute lower respiratory infection (J22). Results: The temporal analysis revealed similar monthly fluctuations of hospital admissions for Crohn's disease, ulcerative colitis, and bacterial intestinal infections. Viral intestinal infections and infectious gastroenteritis were characterized by different seasonal variations that showed no relationship with any of the fluctuations of inflammatory bowel disease or bacterial intestinal infections. Similarly, respiratory infections resulted in marked cyclical variations in hospital admissions unrelated to any changes in inflammatory bowel disease or enteric infections. Conclusions: The similarity in the time trends of Crohn's disease, ulcerative colitis, and bacterial intestinal infections suggests that superinfection by intestinal bacteria are responsible for the fluctuations in hospital admissions for inflammatory bowel disease. (Inflamm Bowel Dis 2008) [source] The Peritoneal Mesothelium Covering the Genital Tract and its Ligaments in the Female Pig Shows Signs of Active FunctionTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 7 2007Jesús Luis Yániz Abstract The aim of this study was to describe the surface features of the peritoneal mesothelium covering the genital tract and adjacent ligaments of the sow to find signs of biosynthetic activation of cells. Surface features of the serosa covering the genital tract and adjacent ligaments from 14 cyclic sows, 7 in the follicular phase and 7 in the luteal phase of the estrous cycle, were examined by histology and scanning electron microscopy. Five additional sows, three in the follicular phase and two in the luteal phase of the estrous cycle, were examined by transmission electron microscopy (TEM). In this study, the presence of cells of the oviductal epithelium in the serosa of the infundibulum and the ampulla, as well as indications of a high functional activity of the mesothelial cells in the areas studied were two aspects that differed from the findings of previous works. Presence of endosalpingeal cells was observed in the serosal surface, showing cyclical variations with a predominance of either ciliated cells during the follicular phase or secretory cells during the luteal phase. Signs of high functional activity of the mesothelial cells included the predominance of cuboidal over flattened cells, a cytoplasm richly supplied with organelles, a dense microvillous coat, numerous primary cilia, and many secretory structures on the surface of cells. These results indicate that the serosa covering the genital area and the adjacent ligaments in the sow has an active epithelium whose coordinating role between reproductive tissues may be far more significant than previously thought. Anat Rec, 2007. © 2007 Wiley-Liss, Inc. [source] Extracting Economic Cycles using Modified AutoregressionsTHE MANCHESTER SCHOOL, Issue 5 2001Alex S. Morton We review a family of modified autoregressive models in both discrete- and continuous-time formulations. We present the case for these models by showing first how a standard discrete-time autoregressive model with orders selected by criteria such as the Akaike information criterion can fail to identify the correct periods of cyclical variations in a simulated example. We then show how the modified models can overcome this failure, and further illustrate this success with a real example of an unemployment series. A new extension of the continuous-time modified model to multivariate series is described. This is applied to a pair of series with mixed monthly, quarterly and annual sampling intervals. Common cyclical components of the two series are then extracted. [source] | |||||||||||||