摘要 :
The growth and recapture rates of Atlantic salmon, Salmo salar L., smolts that had previously matured as parr were compared with those of immature siblings in a sea-ranching experiment in western Norway. The smolts were the offspr...
展开
The growth and recapture rates of Atlantic salmon, Salmo salar L., smolts that had previously matured as parr were compared with those of immature siblings in a sea-ranching experiment in western Norway. The smolts were the offspring of three river populations. They were individually tagged, transferred to cages in a small bay where estuarine salinity gradients had been established and released on four dates from mid-May to early June after either 3 or 7 days of acclimatisation. The previously mature male parr (PMMP) were smaller than their siblings before release, but performed much better during their time in the sea. As grilse, they reached sizes comparable with the formerly immature fish, and their recapture rate was more than four times higher (8.6 vs 2.1%). This difference decreased somewhat during the following years because 0.85% of the immature fish and only 0.1% of PMMP were recaptured as multi-sea-winter salmon. The highly successful marine performance of the PMMP demonstrated that this life history strategy may be more flexible than previously believed.
收起
摘要 :
The last financial crisis has increased the attention into the business of credit rating agencies. In this paper, I investigate the evolution of credit rating standards to measure if rating agencies have moved to different standar...
展开
The last financial crisis has increased the attention into the business of credit rating agencies. In this paper, I investigate the evolution of credit rating standards to measure if rating agencies have moved to different standards over years. First, I present a rating regression model where I employ specific explanatory variables to measure how they impact on ratings outcome. Next, I examine long term issuer credit rating from 1985 to 2013 to analyze how the credit rating agencies have modified their standards over years. I focus on the dynamics of the time variable and I find credit rating agencies strengthen their standards over years since they assign more conservative issuer ratings, holding the companies stable characteristics.
收起
摘要 :
This paper develops an equilibrium model involving credit rating agencies (CRAs), issuers, regulators and investors. The model is based on two key features of the rating industry: the "issuer-pays" business model and competitive m...
展开
This paper develops an equilibrium model involving credit rating agencies (CRAs), issuers, regulators and investors. The model is based on two key features of the rating industry: the "issuer-pays" business model and competitive market structure. By incorporating the ratings shopping by issuers, we investigate the equilibrium decisions of CRAs and the impact of government regulation on the rating market. More importantly, an evolutionary reform plan named the Rating Network Structure, which is an alliance or a network of CRAs' rating approaches, is proposed to improve market efficiency. Simulations demonstrate that this structure plays a significant role in increasing rating accuracy and market profits. Furthermore, this paper reveals the detrimental effect of competition on the credit rating industry.
收起
摘要 :
Fertility in dairy cows has decreased over the last fifty years while milk production per cow has increased. Furthermore, dairy herds become larger resulting in fewer employees per cow, which might also influence reproductive perf...
展开
Fertility in dairy cows has decreased over the last fifty years while milk production per cow has increased. Furthermore, dairy herds become larger resulting in fewer employees per cow, which might also influence reproductive performance. To elucidate the situation in Germany, selected parameters (conception rate, service rate, pregnancy rate, days to first insemination and days open) were studied using data on 148 herds. For statistical analysis the herds were categorized concerning milk yield: (1) < 30 kg, (2) 30-35 kg, and (3) > 35 kg/cow/day as well as concerning herd size: ( 1) < 200, (2) 200-400, (3) 400-1000 and (4) > 1000 milking cows. There was no difference in conception rate among herds. That means on dairy farms of larger size or with high milk yield the chance of an inseminated cow to become pregnant is the same as in small herds or in herds with low milk yield. Small herds (< 200 cows) had lower pregnancy rates than larger herds (200-400 cows). The pregnancy rate in herds with different milk yield was not statistically different. Though there was a trend that dairy farms with higher milk yield (> 30 kg) had higher pregnancy rates. The statistical differences and trends of pregnancy rates are due to higher service rate in larger herds as well as in herds with high milk yield. Therefore, service rate is the key factor for high reproductive performance on dairy farms. Poor fertility is not associated with high milk yield on herd basis or large herd size but may represent inappropriate farm management.
收起
摘要 :
Firms may exploit the option of choosing among different rating agencies in order to pick the highest rating offered. This possibility, known as rating shopping, is relatively limited on the US corporate bond market because the tw...
展开
Firms may exploit the option of choosing among different rating agencies in order to pick the highest rating offered. This possibility, known as rating shopping, is relatively limited on the US corporate bond market because the two main rating agencies (S&Pand Moody's) rate virtually all large bond issuers. In this study, we use the data on corporate bond ratings assigned by two Israeli rating agencies affiliated with S&P and Moody's during the period 2004-2012. We show that while one agency (Midroog) systematically assigned higher ratings, the ratings of the other agency (S&P-Maalot) were inflated due to rating shopping. However, despite the many features that encourage rating inflation, the resulting distortion was relatively small (one notch). This may be a fair price for maintaining a competitive rating industry.
收起
摘要 :
The zooplankton grazer Daphnia magna endures living in water bodies up to moderate densities of cyanobacteria, such as Microcystis spp., known for producing toxic secondary metabolites. Although daphnids are affected via decreased...
展开
The zooplankton grazer Daphnia magna endures living in water bodies up to moderate densities of cyanobacteria, such as Microcystis spp., known for producing toxic secondary metabolites. Although daphnids are affected via decreased food filtering, inhibition of digestive proteases and lethality, development of tolerance against cyanobacterial toxins has also been observed. Aim of our study was to investigate in detail chronic effects of cyanobacterial toxins, with emphasis on microcystin, on D. magna. The animals were exposed chronically for two generations to either microcystin-LR in 5 or 50 mu g L-1, or to cyanobacterial crude extract containing the same amount of total microcystin, starting at neonate stadium. Survival, growth, maturation and fecundity were observed for the first generation during two months. In the offspring survival, maturation, and growth were followed for the first week.Low concentration of microcystin-LR slightly affected the growth and reproduction of parent daphnids. Survivorship decreased during chronic exposure with increasing microcystin concentration. Age to maturity of the offspring increased and their survival decreased after parent generation was exposed to the toxin, even if the offspring were raised in control medium. Besides, cessation of the eggs/embryos was observed and malformation of neonates caused by cyanobacterial toxins was firstly recorded.
收起
摘要 :
The aim of this paper is to examine the main determinants of the rating likelihood of UK companies. We use a binary probit specification to model the main drivers of a firm's propensity to be rated. Using a sample of 245 non-finan...
展开
The aim of this paper is to examine the main determinants of the rating likelihood of UK companies. We use a binary probit specification to model the main drivers of a firm's propensity to be rated. Using a sample of 245 non-financial UK companies over the period 1995-2006, representing up to 2872 firm years, the study establishes important differences in the financial profiles of rated and non-rated firms. The results of the rating likelihood models indicate that the decision to obtain a rating is driven by a company's financial risk, solvency, default risk, public debt issuance, R&D, and institutional ownership, thus identifying a wider range of determinants and extending the current literature. The study also finds that the rating decision can be modelled by means of a contemporaneous or predictive specification without any loss of efficiency or classification accuracy. This offers support to the argument that the rating process is fundamentally forward-looking.
收起
摘要 :
Credit rating agencies (CRAs) play an essential role in efficiently allocating capital in the financial system. However, several researchers have highlighted shortcomings of CRAs, leading to drastic consequences such as the 2008 f...
展开
Credit rating agencies (CRAs) play an essential role in efficiently allocating capital in the financial system. However, several researchers have highlighted shortcomings of CRAs, leading to drastic consequences such as the 2008 financial crisis. The paper focuses on the competition among CRAs as one of the critical drivers of issues plaguing the credit rating industry. The paper uses quantitative and regression techniques to check the impact of competition on a firm’s credit rating. The paper utilizes firm-level financial and credit rating data from India. The paper uses dual ratings to check whether competition leads to rating inflation and shopping practices in the credit rating industry. The paper finds that CRA inflates a firm’s credit rating due to competition from other CRAs. Rating shopping is also evident in the credit rating industry, driven by competition between CRAs to gain new clients. The paper’s findings also indicate that increased competition for large-size firms business leads to CRAs showing leniency when rating such firms. The results raise the need for regulators to actively monitor and control the competition among CRAs to ensure the accuracy of credit ratings.
收起
摘要 :
Ghost crabs Ocypode ceratophthalmus were exercised in air and water to measure CO2 and O-2 exchange rates using the method of instantaneous measurements of oxygen consumption rate (MO2) where applicable. Average heart rate increas...
展开
Ghost crabs Ocypode ceratophthalmus were exercised in air and water to measure CO2 and O-2 exchange rates using the method of instantaneous measurements of oxygen consumption rate (MO2) where applicable. Average heart rate increased from 100 to nearly 400 pulses per minute after five minutes of exercise on a treadmill at a run rate of 0.133 m s(-1). It took less than a minute for oxygen taken up through the lung epithelium from the air inside the branchial cavity to reach the maximal oxygen consumption rate of 26.1 mmol O-2 kg(-1) h(-1). Resting MO2 was 4.06 mmol O-2 kg(-1) h(-1) in air, but decreased to 3.37 mmol O-2 kg(-1) h(-1) in seawater. Radioactive CO2 from injected l-lactate is released linearly by the lung. The percent accumulated 14-CO2 in exhaled air, plotted against time, intersects zero time on the x-axis, indicating rapid gas exchange at the lung surface. The P-50 values for native haemocyanin of 4.89 mm Hg before exercise, and 8.99 mm Hg after exercise, are typical of a high-affinity haemocyanin usually associated with terrestrial crabs. The current notion that Ocypode ceratophthalmus drown when submerged in seawater was not substantiated by our experiments. MO2 in seawater increased from 3.37 mmol O-2 kg(-1) h(-1) for resting crabs to 5.72 mmol O-2 kg(-1) h(-1) during exercise. When submerged by wave-seawater in the natural environment and during exercise in respirometer-seawater O. ceratophthalmus do not swim but, having a specific density of 1.044, float nearly weightless with a minimum of body movements.
收起
原文获取