Volatility Smirk as an Externality of Agency Conflict and Growing Debt

Since Black (1976), the source of the stock price volatility smirk has remained a controversy. The volatility smirk is a side effect of agency conflict. An important distinction is that the smirk occurs in the optimum, even after agency conflict has been resolved. The slope of the smirk is found to increase with the severity of the initial agency conflict between management and investors. It is predicted that the higher is the compensation of the manager, the steeper will be the volatility smirk, both for time series and cross sections of companies. These results may help to disentangle the leverage effect from other potential explanations like volatility feedback, the time-varying risk premium, and a down-market effect

Estimating Implied Recovery Rates from the Term Structure of CDS Spreads

Credit risk models should reflect the observation that the relevant value of collateral is generally not the average value of the asset over all possible states of nature. In most cases, the relevant value of collateral for the lender is its secondary market value in bad states of nature, where marginal utilities are high. Although the negative correlation between recovery rates and default probabilities is well documented, the majority of pricing models does not allow for correlation between the two. In this paper, we propose a relatively parsimonious reduced-form continuous time model that estimates expected recovery rates and default probabilities from the term structure of CDS spreads. The parameters of the model and latent factors driving recovery risk and default risk are estimated using a Bayesian MCMC algorithm. We nd that the Bayesian deviance information criterion (DIC) favors the model with stochastic recovery over constant recovery. We also observe that for companies with a good rating, implied constant recovery rates do not dier much from stochastic recovery. However, if a company is very risky, then forward stochastic recovery rates are signicantly lower at longer maturities

Heterozygous Hfe gene deletion leads to impaired glucose homeostasis, but not liver injury in mice fed a high-calorie diet

Heterozygous mutations of the Hfe gene have been proposed as cofactors in the development and progression of nonalcoholic fatty liver disease (NAFLD). Homozygous Hfe deletion previously has been shown to lead to dysregulated hepatic lipid metabolism and accentuated liver injury in a dietary mouse model of NAFLD. We sought to establish whether heterozygous deletion of Hfe is sufficient to promote liver injury when mice are exposed to a high-calorie diet (HCD). Eight-week-old wild-type and Hfe mice received 8\ua0weeks of a control diet or HCD. Liver histology and pathways of lipid and iron metabolism were analyzed. Liver histology demonstrated that mice fed a HCD had increased NAFLD activity score (NAS), steatosis, and hepatocyte ballooning. However, liver injury was unaffected by Hfe genotype. Hepatic iron concentration (HIC) was increased in Hfe mice of both dietary groups. HCD resulted in a hepcidin-independent reduction in HIC. Hfe mice demonstrated raised fasting serum glucose concentrations and HOMA-IR score, despite unaltered serum adiponectin concentrations. Downstream regulators of hepatic de novo lipogenesis (pAKT, SREBP-1, Fas, Scd1) and fatty acid oxidation (AdipoR2, Pparα, Cpt1) were largely unaffected by genotype. In summary, heterozygous Hfe gene deletion is associated with impaired iron and glucose metabolism. However, unlike homozygous Hfe deletion, heterozygous gene deletion did not affect lipid metabolism pathways or liver injury in this model

SUPEROVULATION NEW MODELS INCLUDING FSH DOSE REDUCTION AND NEW PREPARATIONS

It was estimated that every year around the world, approximately half a million bovineembryos are produced (Cremonesi, 2020). The classic superovulation program involvesadministering of a series of FSH injections to embryo donor cows starting on day 9-12 of theoestrus cycle. In Europe, Pluset and Folltropin preparations are commercially used for thispurpose, both available on the market in Poland (Kulus, 2019). This is the mechanismunderlying superovulatory protocols that were developed in the 1980s, which were furtherimproved by refining hormonal preparations like human menopausal gonadotropin (HMG),equine chorionic gonadotropin (eCG), or follicle-stimulating hormone (FSH) from porcine orovine pituitaries (Cremonesi 2020). Superovulation protocols vary widely based on the FSHsource, the diluent used, the number and timing of FSH injections and the timing andutilisation of various prostaglandins, controlled internal progesterone releasing devices,gonadotrophin-releasing hormone, and other means of controlling follicular development andovulation (Mikkola, 2019). These may include nutritional status, reproductive history, age,season, breed, effects of repeated superovulations and ovarian status at the time oftreatment (Cremonesi 2020). An approach that has shown promise is to initiate FSHtreatments at the time of the emergence of the first follicular wave following GnRH-inducedovulation. Using of aspiration of dominant follicle is possible to induce new follicular wave.This simple biotechnical treatment has a final impact on the number of in vivo producedembryos. Its seems, that of the interval from follicle aspiration to initiation of lengthened FSHtreatment (Cirit, 2019). However, it has been shown that it may be possible to ignorefollicular wave status, and by extending the treatment protocol induce smaller follicles togrow and reach maturity and superovulate. Finally, the short halflife of pituitary FSHnecessitates twice daily treatments which are time-consuming, stressful and subject to error.Recent treatment protocols have permitted superstimulation with a single or alternatively,two FSH treatments, reducing the need for animal handling during FSH treatment (Mapletoft,2013). A single dose protocol of FSH for superstimulation in cattle may improve complianceand superovulatory response. A single subcutaneous (sc) administration of pFSH wasefficacious, but response depended on body condition and injection site; the adipose tissuepad behind the shoulder was most efficacious. Inconsistent results in Holsteins were partiallyovercome by sc administration of 75% of the total pFSH dose behind the shoulder on the firstday followed by 25% 48 h later (Bo, 2018). The split-single injection given ischiorectal fossa(split-single IRF administration had a comparable superovulatory response to the traditionaltwice-daily protocol. Moreover, the ovulation rate, ovarian follicle responses, and embryoquality were affected by heat stress (Chumchai, 2021, Ratsiri, 2022). In the other study theovarian responses in the split-single IRF group were similar to those of the control group (p >.05) but higher compared with the split-single IM group. Regardless of the route ofadministration of FSH. The high THI affected ovulation rate as well as the numbers oftransferable embryos and degenerated embryos (Thanaporn, 2021). A recombinant longactingovine follicle stimulating hormone (roFSH) has been devised and its biologicaleffectiveness following a single dose has been assessed in several experiments under fieldconditions, in pasture-based beef and dairy farming in New Zealand. Owing to the molecularstructure of this long-acting roFSH, which includes additional N-glycosylation sites, a singledose combined with a simple CIDR-based superovulatory regime elicits successful ovarianstimulation with averages of 11.8 corpora lutea and of 6.1 good quality embryos collected incattle. Solid performance of this novel FSH was demonstrated in several beef and dairybreeds which included yearling heifers and mixed age cows, with embryo production resultsin the same range as those observed nowadays with eight doses of commercial pituitary FSH(pFSH). Viable embryos produced from these collections, when implanted either fresh orfrozen and thawed, gave pregnancy rates in recipients similar to those collected from cowsand heifers superstimulated with pFSH. Repeated superovulatory treatment of the same cowswas not associated with a decrease in ovarian response or embryo yield. The singleadministration of this long-acting roFSH when combined with a modified simplesuperovulatory regime has the advantage of reducing animal welfare concerns, loweringlabour resource requirements and giving similar results to other commercially preparedpituitary FSH extracts (Sanderson, 2020, Gutierrez-Rreinoso, 2022). It is well known that 70%of embryos are produced by 30% of donors. This very high variability was tried to bereduced, with very good results by administrating platelet rich plasma (PRP) inside the ovarybefore the superovulation protocol. This hemocomponent is rich in growth factors andcytokines known for their regenerative properties in human and veterinary medicine(Cremonesi, 2020, Cirit, 2020)

Laboratory diagnosis of Inflammatory Bowel Disease (IBD)

AbstractStudy to compare the results obtained by two separate reference libraries for serological assays utlilized in the diagnosis and differentiation of Crohn's disease and ulcerative colitis, and to assess the clinical utility of the outer-membrane porin C (OmpC) IgA assay in IBD

Biases in the perceived timing of perisaccadic perceptual and motor events

Subjects typically experience the temporal interval immediately following a saccade as longer than a comparable control interval. One explanation of this effect is that the brain antedates the perceptual onset of a saccade target to around the time of saccade initiation. This could explain the apparent continuity of visual perception across eye movements. Thisantedating account was tested in three experiments in which subjects made saccades of differing extents and then judged either the duration or the temporal order of key events. Postsaccadic stimuli underwent subjective temporal lengthening and had early perceived onsets. A temporally advanced awareness of saccade completion was also found, independently of antedating effects. These results provide convergent evidence supporting antedating and differentiating it from other temporal biases

Spurious cross-sectional dependence in credit spread changes

In order to understand the lingering credit risk puzzle and the apparent segmentation of the stock market from credit markets, we need to be able to assess the strength of the cross-sectional dependence in credit spreads. This turns out to be a non-trivial task due to the extreme data sparsity that is typical for any panel of credit spreads that is extracted from corporate bond transactions. The problem of data sparsity has led to some erroneous conclusions in the literature, including inferences that have been drawn from spurious cross-sectional dependence in credit spread changes. Understanding the pitfalls leads to improved estimation of the latent factor in credit spread changes and its characteristics.</p

Screening for antinuclear antibodies by enzyme immunoassay

Journal ArticleIndirect fluorescent antibody (IFA) is the most widely used method in clinical laboratories to screen for autoantibodies against a wide variety of nuclear antigens. Recently, a number of antinuclear antibody (ANA) enzyme immunoassay (EIA) screens have become commercially available and claim to be an alternative method to screen for ANAs. Given the subjectivity of technical interpretation of IFA and the high number of ANA negative samples, a suitable EIA method for ANA screening would be beneficial to clinical laboratories with large sample volumes. Five ANA EIA screens were compared (Efias, Helix, Sanofi, ThcraTcst and Zeus) to IFA using a human epithelial cell line (HEp-2). Sera from 601 patients submitted to our reference laboratory for autoimmune testing, and from 202 normal healthy blood donors, were included in this study. Samples with discordant results between IFA and EIA were further analyzed using single antigen EIAs for SSA, SSB, Sm, RNP, Scl-70, histones, dsDNA, and ssDNA

Polymerase chain reaction detection of Lyme disease: correlation with clinical manifestations and serologic responses

Journal ArticleThe Author's have developed a simple, nested polymerase chain reaction (PCR) assay for amplification of an outer surface protein A (OspA) gene fragment of Borrelia burgdorferi using rapid temperature cycling and ethidium bromide detection on agarose gels, and applied it to the diagnosis of Lyme disease in humans. With denaturing and annealing temperature spikes instead of holds, cycle times were less than 20 minutes for a 30-cycle amplification. Using this rapid cycle PCR technique, as few as 5 spirochetes per mL of phosphate buffered saline were detected. In addition, B burgdorferi DNA was detected from spirochetes that had been spiked into one of several types of human body fluids including serum, synovial fluid, and cerebrospinal fluid (CSF). A number o f clinical samples, which had been tested for Lyme immunoglobulin M (IgM) and immunoglobulin G (IgG) antibody were also examined