What does financial volatility tell us about macroeconomic fluctuations?

This paper provides an extensive analysis of the predictive ability of financial volatility measures for economic activity. We construct monthly measures of aggregated and industry-level stock volatility, and bond market volatility from daily returns. We model log financial volatility as composed of a long-run component that is common across all series, and a short-run component. If volatility has components, volatility proxies are characterized by large measurement error, which veils analysis of their fundamental information and relationship with the economy. We find that there are substantial gains from using the long term component of the volatility measures for linearly projecting future economic activity, as well as for forecasting business cycle turning points. When we allow for asymmetry in the long-run volatility component, we find that it provides early signals of upcoming recessions. In a real-time out-of-sample analysis of the last recession, we find that these signals are concomitant with the first signs of distress in the financial markets due to problems in the housing sector around mid-2007 and the implied chronology is consistent with the crisis timeline.Realized Volatility, Business Cycles, Forecasting, Dynamic Factor Models, Markov Switching

What prevents DNA replication between meiosis I and -II in yeast?

During meiosis, a single round of DNA replication is followed by two consecutive rounds of chromosome segregation. While the suppression of DNA replication between meiosis I and –II is one of the defining features of meiosis, its mechanism has remained unclear. The control of DNA replication has been studied extensively in proliferating cells in which DNA replication during S phase strictly alternates with chromosome segregation at mitosis. The mechanism ensuring that each sequence is replicated only once per cell cycle is based on the dual function of Cdk1: low Cdk1 activity after mitosis allows the establishment of prereplicative complexes at replication origins (origin licensing). Activation of Cdk1 at the onset of S phase then initiates DNA replication (origin firing) by converting the pre-replicative complex to the post-replicative complex. Since high Cdk1 activity inhibits the reformation of pre-replicative complexes, the next round of DNA replication cannot occur until after Cdk1 has been inactivated during mitosis when replicated chromosomes segregate. However, applying this concept to meiosis would trigger an additional round of DNA replication because Cdk1 activity drops and then re-appears between meiosis I and –II. Two ideas have been proposed to solve this problem: in Xenopus eggs, Cdk1 activity is reduced rather than completely destroyed between meiosis I and –II, while in yeast, a Cdk1-related kinase, called Ime2, was thought to prevent origin relicensing at anaphase I. We have tested these ideas by artificially inactivating and then reactivating Cdk1 and Ime2 at anaphase I. Remarkably, DNA replication was not induced even when both kinases were simultaneously inhibited and re-activated at anaphase I. Thus, additional mechanisms must prevent DNA replication between meiosis I and –II

What Prevents DNA Replication between Meiosis I and II in Yeast?

During meiosis, a single round of DNA replication is followed by two consecutive rounds of chromosome segregation. While the suppression of DNA replication between meiosis I and –II is one of the defining features of meiosis, its mechanism has remained unclear. The control of DNA replication has been studied extensively in proliferating cells in which DNA replication during S phase strictly alternates with chromosome segregation at mitosis. The mechanism ensuring that each sequence is replicated only once per cell cycle is based on the dual function of Cdk1: low Cdk1 activity after mitosis allows the establishment of prereplicative complexes at replication origins (origin licensing). Activation of Cdk1 at the onset of S phase then initiates DNA replication (origin firing) by converting the pre-replicative complex to the post-replicative complex. Since high Cdk1 activity inhibits the reformation of pre-replicative complexes, the next round of DNA replication cannot occur until after Cdk1 has been inactivated during mitosis when replicated chromosomes segregate. However, applying this concept to meiosis would trigger an additional round of DNA replication because Cdk1 activity drops and then re-appears between meiosis I and –II. Two ideas have been proposed to solve this problem: in Xenopus eggs, Cdk1 activity is reduced rather than completely destroyed between meiosis I and –II, while in yeast, a Cdk1-related kinase, called Ime2, was thought to prevent origin relicensing at anaphase I. We have tested these ideas by artificially inactivating and then reactivating Cdk1 and Ime2 at anaphase I. Remarkably, DNA replication was not induced even when both kinases were simultaneously inhibited and re-activated at anaphase I. Thus, additional mechanisms must prevent DNA replication between meiosis I and –II

What prevents DNA replication between meiosis I and -II in yeast?

During meiosis, a single round of DNA replication is followed by two consecutive rounds of chromosome segregation. While the suppression of DNA replication between meiosis I and –II is one of the defining features of meiosis, its mechanism has remained unclear. The control of DNA replication has been studied extensively in proliferating cells in which DNA replication during S phase strictly alternates with chromosome segregation at mitosis. The mechanism ensuring that each sequence is replicated only once per cell cycle is based on the dual function of Cdk1: low Cdk1 activity after mitosis allows the establishment of prereplicative complexes at replication origins (origin licensing). Activation of Cdk1 at the onset of S phase then initiates DNA replication (origin firing) by converting the pre-replicative complex to the post-replicative complex. Since high Cdk1 activity inhibits the reformation of pre-replicative complexes, the next round of DNA replication cannot occur until after Cdk1 has been inactivated during mitosis when replicated chromosomes segregate. However, applying this concept to meiosis would trigger an additional round of DNA replication because Cdk1 activity drops and then re-appears between meiosis I and –II. Two ideas have been proposed to solve this problem: in Xenopus eggs, Cdk1 activity is reduced rather than completely destroyed between meiosis I and –II, while in yeast, a Cdk1-related kinase, called Ime2, was thought to prevent origin relicensing at anaphase I. We have tested these ideas by artificially inactivating and then reactivating Cdk1 and Ime2 at anaphase I. Remarkably, DNA replication was not induced even when both kinases were simultaneously inhibited and re-activated at anaphase I. Thus, additional mechanisms must prevent DNA replication between meiosis I and –II

Trend to equilibrium for run and tumble equations with non-uniform tumbling kernels

We study the long-time behaviour of a run and tumble model which is a kinetic-transport equation describing bacterial movement under the effect of a chemical stimulus. The experiments suggest that the non-uniform tumbling kernels are physically relevant ones as opposed to the uniform tumbling kernel which is widely considered in the literature to reduce the complexity of the mathematical analysis. We consider two cases: (i) the tumbling kernel depends on the angle between pre- and post-tumbling velocities, (ii) the velocity space is unbounded and the post-tumbling velocities follow the Maxwellian velocity distribution. We prove that the probability density distribution of bacteria converges to an equilibrium distribution with explicit (exponential for (i) and algebraic for (ii)) convergence rates, for any probability measure initial data. To the best of our knowledge, our results are the first results concerning the long-time behaviour of run and tumble equations with non-uniform tumbling kernels.Comment: 22 pages 2 figure

Identification of heat-resistant chemical components of Ferula elaeochytris root extracts by gas chromatographymass spectrometry

Purpose: To determine the chemical composition of Ferula elaeochytris, a plant with traditional medicinal uses, and to investigate its potential benefits.Methods: Ferula elaeochytris specimens were collected from Engizek plateau of Kahramanmaras, Turkey in early June 2017, and dried in a cool and dry place at room temperature. Once dried, they were ground into a powder using a plant grinder. A Soxhlet extractor was employed for extraction of the powdered roots using diethyl ether solvent for 4 h, and then subsequently evaporated using a rotary evaporator. The extract was analysed by gas chromatography mass spectrometry (GC-MS) to reveal the components of F. elaeochytris.Results: Khusinol, ferutinin and beta-ionone, components with anti-inflammatory phytoestrogen, antiproliferative and antioxidant activities, were found in high levels (25.9, 13.9 and 22.9 %, respectively in F. elaeochytris root extract, In addition α-pinene, which has anti-inflammatory, bronchodilator, hypoglycaemic and anticarcinogenic effects, was found at lower levels (12.9 % or less).Conclusion: The results reveal the presence of some therapeutically beneficial components of F. elaeochytris root extract, including compounds with antioxidant and anti-inflammatory effects.Keywords: Ferula elaeochytris, Khusinol, Ferutinin, Beta-ionone, Anti-inflammatory Phytoestrogen, Antiproliferative, Antioxidan

Re-conceiving Afghan cellular architecture for the reconstruction of rural schools

Afghanistan suffers from a quarter century of war that has resulted in a devastated infrastructure and a generation of Afghans who have lived without a local school. This paper presents an architectural design investigation that seeks ways of synthesizing traditional social-cultural and formalspatial attributes with refined material and construction capabilities becoming increasingly available worldwide. In the spirit of George Kubler's thesis of invention and variation, stabilized compressed brick construction and computer aided structural analysis are introduced as refinements within the Afghan building tradition

Structure and thermal behavior of nanocrystalline boehmite

First, the structural features of nanocrystalline boehmite synthesized by hydrolysis of aluminum sec-butoxide according to the Yoldas method are reported. The nanosized boehmite consists of rectangular platelets averaging 8 by 9 nm and 2–3 nm in thickness which contain a large excess of water. Dehydration by heating under vacuum induced an increase in the specific surface area, down to a minimum water content ( 0.2 H2O per Al2O3); values up to 470 m2/g can be reached. However this enlargement of specific surface area only results from water loss, the surface area remaining constant. The particle morphology, the excess of water, as well as the specific surface area, depend on the amount of acid used for the peptization during the synthesis. Second, a comprehensive investigation of the dehydration kinetics is presented. The simulations of the non-isothermal experiments at constant heating rates show that thermally stimulated transformation of nanocrystalline boehmite into alumina can be accurately modeled by a 4-reaction mechanism involving: (I) the loss of physisorbed water, (II) the loss of chemisorbed water, (III) the conversion of boehmite into transition alumina, (IV) the dehydration of transition alumina (loss of residual hydroxyl groups). The activation energy of each step is found to be very similar for experiments done in various conditions (heating rate, atmosphere, kind of sample,…)

The bright optical/NIR afterglow of the faint GRB 080710 - Evidence for a jet viewed off axis

We investigate the optical/near-infrared light curve of the afterglow of GRB 080710 in the context of rising afterglows. Optical and near-infrared photometry was performed using the seven channel imager GROND and the Tautenburg Schmidt telescope. X-ray data were provided by the X-ray Telescope onboard the Swift satellite. The optical/NIR light curve of the afterglow of GRB 080710 is dominated by an initial increase in brightness, which smoothly turns over into a shallow power law decay. The initially rising achromatic light curve of the afterglow of GRB 080710 can be accounted for with a model of a burst viewed off-axis or a single jet in its pre deceleration phase and in an on-axis geometry. An unified picture of the afterglow light curve and prompt emission properties can be obtained with an off-axis geometry, suggesting that late and shallow rising optical light curves of GRB afterglows might be produced by geometric effects.Comment: 9 pages, 4 figures, accepted by A and

Surgical treatment with rhomboid excision and Limberg flap technique under spinal anesthesia of 23 young with pilonidal sinus disease

Aim: To present the experience of treatment with Limberg flap procedure under spinal anesthesia in 23 young patients with pilonidal sinus disease. Methods: This was a retrospective study of 23 young patients who underwent surgery for pilonidal sinus disease under spinal anesthesia between January 2011 and November 2017 in the Division of Pediatric Surgery. All patients were evaluated for age, sex, clinical diagnosis, and body mass index, and infection, duration of symptoms, treatment, healing time, recurrences, complications and results.  Results: Of the 23 patients, 4 (17%) were male, and 19 (83%) were female. The mean age of the patients was 15.21 ± 2.8 years and the mean symptom duration was 4 ± 2.6 months. In 13 patients (56.5%), there was one or more sagittal lines in the midline and the mean sinus number of the patients was 2.12 ± 0.60. Pain was the most important complaint affecting the quality of life of the patient. The mean body mass index was 26.33 ± 2.54 kg / m2, and 47.8% (n = 11) were high BMI and 53.2% were normal BMI. One patient had temporary headache and one patient had urinary retention. Wound infection occurred in 2 patients (8.6%). Recurrence was not observed in patients.  Conclusion: In this study, pilonidal sinus disease was treated with Limberg flap procedure under spinal anesthesia. The combination of these two applications in patients with pilonidal sinus may provide significant advantages, such as rapid recovery and short hospital stay, early return to daily activities, low complications, and recurrence rates