Is Unlevered Firm Volatility Asymmetric?

Asymmetric volatility refers to the stylized fact that stock volatility is negatively correlated to stock returns. Traditionally, this phenomenon has been explained by the financial leverage effect. This explanation has recently been challenged in favor of a risk premium based explanation. We develop a new, unlevering approach to document how well financial leverage, rather than size, beta, book-to-market, or operating leverage, explains volatility asymmetry on a firm-by-firm basis. Our results reveal that, at the firm level, financial leverage explains much of the volatility asymmetry. This result is robust to different unlevering methodologies, samples, and measurement intervals. However, we find that financial leverage does not explain index-level volatility asymmetry, which is consistent with theoretical results in Aydemir, Gallmeyer and Hollifield (2006).Volatility asymmetry, Financial leverage, Financial Economics, Research Methods/ Statistical Methods, G12,

Effects of germination time on antioxidant contents and enzymatic antioxidant activities in the grains of different rice varieties

Tocopherols, tocotrienols and γ-oryzanol are potent antioxidants of rice grains, and they may play an important role in the germination and growth of rice plants. In this study, the objective was to examine the effects of germination time on contents of Toc, T3, GO and ascorbate, as well as enzymatic antioxidant activities in the grains of two different rice varieties, namely TN71 and KS139. Samplings were conducted at 0, 3, 6 and 9 days after imbibition. The results showed that T3 and GO contents, but not Toc increased during seedling emergence. Toc content showed a trend of decrease from 0 DAI to 6 DAI. Contrasting to KS139, the AsA content in the grains of TN71 increased with increasing DAI. KS139 showed a time-dependent increase in the dehydroascorbate level, while that of TN71 remains unchanged at all times. TN71 showed significant increases in superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase activities in the late germination stages (9 DAI); with the exception of APX, KS139 exhibited a relatively constant enzymatic activities throughout the germination period. The changes in the malondialdehyde and H2O2 levels were minimum before 6 DAI, however a significant increase was noted at 9 DAI. This study indicates that besides the enzymatic antioxidants, the increase in T3 and GO contents may play a role in countering the oxidative stress during rice grain germination

Anti-tumour compounds illudin S and Irofulven induce DNA lesions ignored by global repair and exclusively processed by transcription- and replication-coupled repair pathways.

Illudin S is a natural sesquiterpene drug with strong anti-tumour activity. Inside cells, unstable active metabolites of illudin cause the formation of as yet poorly characterised DNA lesions. In order to identify factors involved in their repair, we have performed a detailed genetic survey of repair-defective mutants for responses to the drug. We show that 90% of illudin's lethal effects in human fibroblasts can be prevented by an active nucleotide excision repair (NER) system. Core NER enzymes XPA, XPF, XPG, and TFIIH are essential for recovery. However, the presence of global NER initiators XPC, HR23A/HR23B and XPE is not required, whereas survival, repair and recovery from transcription inhibition critically depend on CSA, CSB and UVS, the factors specific for transcription-coupled NER. Base excision repair and non-homologous end-joining of DNA breaks do not play a major role in the processing of illudin lesions. However, active RAD18 is required for optimal cell survival, indicating that the lesions also block replication forks, eliciting post-replication-repair-like responses. However, the translesion-polymerase DNA pol eta is not involved. We conclude that illudin-induced lesions are exceptional in that they appear to be ignored by all of the known global repair systems, and can only be repaired when trapped in stalled replication or transcription complexes. We show that the semisynthetic illudin derivative hydroxymethylacylfulvene (HMAF, Irofulven), currently under clinical trial for anti-tumour therapy, acts via the same mechanism

Batch Scheduling of Deteriorating Products

In this paper we consider the problem of scheduling N jobs on a single machine, where the jobs are processed in batches and the processing time of each job is a simple linear increasing function depending on job’s waiting time, which is the time between the start of the processing of the batch to which the job belongs and the start of the processing of the job. Each batch starts from the setup time S. Jobs which are assigned to the batch are being prepared for the processing during time S0 < S. After this preparation they are ready to be processed one by one. The non-negative number bi is associated with job i. The processing time of the i-th job is equal to bi(si − (sib + S0)), where sib and si are the starting time of the b-th batch to which the i-th job belongs and the starting time of this job, respectively. The objective is to minimize the completion time of the last job. We show that the problem is NP-hard. After that we present an O(N) time algorithm solving the problem optimally for the case bi = b. We further present an O(N2) time approximation algorithm with a performance guarantee 2

Effects of a portion design plate on food group guideline adherence among hospital staff

Food group guideline adherence is vital to prevent obesity and diabetes. Various studies have demonstrated that environmental variables influence food intake behaviour. In the present study we examined the effect of a portion design plate with food group portion guidelines demarcated by coloured lines (ETE Plate™). A two-group quasi-experimental design was used to measure proportions of carbohydrate, vegetable and protein portions and user experience in a hospital staff lounge setting in Singapore. Lunch was served on the portion design plate before 12.15 hours. For comparison, a normal plate (without markings) was used after 12.15 hours. Changes in proportions of food groups from 2 months before the introduction of the design plate were analysed in a stratified sample at baseline (859 subjects, all on normal plates) to 1, 3 and 6 months after (in all 1016 subjects on the design plate, 968 subjects on the control plate). A total of 151 participants were asked about their experiences and opinions. Between-group comparisons were performed using ___t___ tests. Among those served on the portion design plate at 6 months after its introduction, the proportion of vegetables was 4·71 % (P < 0·001) higher and that of carbohydrates 2·83 % (P < 0·001) lower relative to the baseline. No significant change was found for proteins (−1·85 %). Over 6 months, we observed different change patterns between the different food group proportions. While participants were positive about the portion design plate, they did not think it would influence their personal behaviour. A portion design plate might stimulate food group guideline adherence among hospital staff and beyond

D* Production in Deep Inelastic Scattering at HERA

This paper presents measurements of D^{*\pm} production in deep inelastic scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The data have been taken with the ZEUS detector at HERA. The decay channel $D^{*+}\to (D^0 \to K^- \pi^+) \pi^+$ (+ c.c.) has been used in the study. The $e^+p$ cross section for inclusive D^{*\pm} production with $5<Q^2<100 GeV^2$ and $y<0.7$ is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region {$1.3<p_T(D^{*\pm})<9.0$ GeV and $| \eta(D^{*\pm}) |<1.5$}. Differential cross sections as functions of p_T(D^{*\pm}), $\eta(D^{*\pm}), W$ and $Q^2$ are compared with next-to-leading order QCD calculations based on the photon-gluon fusion production mechanism. After an extrapolation of the cross section to the full kinematic region in p_T(D^{*\pm}) and $\eta$(D^{*\pm}), the charm contribution $F_2^{c\bar{c}}(x,Q^2)$ to the proton structure function is determined for Bjorken $x$ between 2 $\cdot$ 10$^{-4}$ and 5 $\cdot$ 10$^{-3}$.Comment: 17 pages including 4 figure

Observation of Scaling Violations in Scaled Momentum Distributions at HERA

Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of $x$ and $Q^2$ using the ZEUS detector. The evolution of the scaled momentum, $x_p$, with $Q^2,$ in the range 10 to 1280 $GeV^2$, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of $Q^2$.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde

Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the $\gamma p$ centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil

Loss of Grem1-lineage chondrogenic progenitor cells causes osteoarthritis

Published online: 31 October 2023Osteoarthritis (OA) is characterised by an irreversible degeneration of articular cartilage. Here we show that the BMP-antagonist Gremlin 1 (Grem1) marks a bipotent chondrogenic and osteogenic progenitor cell population within the articular surface. Notably, these progenitors are depleted by injury-induced OA and increasing age. OA is also caused by ablation of Grem1 cells in mice. Transcriptomic and functional analysis in mice found that articular surface Grem1-lineage cells are dependent on Foxo1 and ablation of Foxo1 in Grem1-lineage cells caused OA. FGFR3 signalling was confirmed as a promising therapeutic pathway by administration of pathway activator, FGF18, resulting in Grem1-lineage chondrocyte progenitor cell proliferation, increased cartilage thickness and reduced OA. These findings suggest that OA, in part, is caused by mechanical, developmental or age-related attrition of Grem1 expressing articular cartilage progenitor cells. These cells, and the FGFR3 signalling pathway that sustains them, may be effective future targets for biological management of OA.Jia Q. Ng, Toghrul H. Jafarov, Christopher B. Little, Tongtong Wang, Abdullah M. Ali, YanMa, Georgette A. Radford, Laura Vrbanac, Mari Ichinose, Samuel Whittle, David J. Hunter, Tamsin R. M. Lannagan, Nobumi Suzuki, JarradM. Goyne, Hiroki Kobayashi, Timothy C. Wang, David R. Haynes, Danijela Menicanin, Stan Gronthos, Daniel L. Worthley, Susan L. Woods and Siddhartha Mukherje