ADIABATIC CONDITIONS FOR FINANCIAL SYSTEMS

In the Black-Scholes context we consider the probability distribution function (PDF) of financial returns implied by volatility smile and we study the relation between the decay of its tails and the fitting parameters of the smile. We show that, considering a scaling law derived from data, it is possible to get a new fitting procedure of the volatility smile that considers also the exponential decay of the real PDF of returns observed in the financial markets. In addiction, we show that this approach based on a volatility smile leads to relative minima for the distribution function ("bad" probabilities) never observed in real data and, in the worst cases, negative probabilities. We show that these undesirable effects can be eliminated by requiring "adiabatic" conditions on the volatility smile. Our study finds application in the Risk Management activities where the tails characterization of financial returns PDF has a central role for the risk estimation

Evaluation of phytotoxic, cytotoxic and antiparasitic in vitro activities of Borreria verticillata, a weed of Panamanian coffee crops.

In recent years, there have been significant changes in weed populations in different agricultural production systems. Coffee production is economically important in the Republic of Panama, and the specie Borreria verticillata affects a significant portion of this crop. Weeds may directly affect the yields of economically important plants through two main ways: by producing allelochemicals which inhibit plant growth or by competition for nutrients and water availability in the soil. Borreria verticillata was selected to evaluate its phytotoxic activity by which this weed affects the coffee crops. In addition, we carried out antiparasitic evaluations for determining the activity of Borreria verticillata extract against three human parasites: Leishmania donovani, Trypanosoma cruzi and Plasmodium falciparum. The experimental results revealed that the extract prepared using the aerial parts of Borreria verticillata did not show significant phytotoxic and cytotoxic effects. On the other hand, the antiparasitic evaluations showed that the extract possessed only moderate activities against Plasmodium falciparum. Finally, we proceeded to identify the major chemical components of this extract and we obtained three known compounds: scualene (1), epoxyscualene (2) and borrecapine (3).In recent years, there have been significant changes in weed populations in different agricultural production systems. Coffee production is economically important in the Republic of Panama, and the specie Borreria verticillata affects a significant portion of this crop. Weeds may directly affect the yields of economically important plants through two main ways: by producing allelochemicals which inhibit plant growth or by competition for nutrients and water availability in the soil. Borreria verticillata was selected to evaluate its phytotoxic activity by which this weed affects the coffee crops. In addition, we carried out antiparasitic evaluations for determining the activity of Borreria verticillata extract against three human parasites: Leishmania donovani, Trypanosoma cruzi and Plasmodium falciparum. The experimental results revealed that the extract prepared using the aerial parts of Borreria verticillata did not show significant phytotoxic and cytotoxic effects. On the other hand, the antiparasitic evaluations showed that the extract possessed only moderate activities against Plasmodium falciparum. Finally, we proceeded to identify the major chemical components of this extract and we obtained three known compounds: scualene (1), epoxyscualene (2) and borrecapine (3)

Magnetic Reversal Time in Open Long Range Systems

Topological phase space disconnection has been recently found to be a general phenomenon in isolated anisotropic spin systems. It sets a general framework to understand the emergence of ferromagnetism in finite magnetic systems starting from microscopic models without phenomenological on-site barriers. Here we study its relevance for finite systems with long range interacting potential in contact with a thermal bath. We show that, even in this case, the induced magnetic reversal time is exponentially large in the number of spins, thus determining {\it stable} (to any experimental observation time) ferromagnetic behavior. Moreover, the explicit temperature dependence of the magnetic reversal time obtained from the microcanonical results, is found to be in good agreement with numerical simulations. Also, a simple and suggestive expression, indicating the Topological Energy Threshold at which the disconnection occurs, as a real energy barrier for many body systems, is obtained analytically for low temperature

Multi-Omics and Genome Editing Studies on Plant Cell Walls to Improve Biomass Quality

Biomass is one of the most important sources of renewable energy and plays an important role in reducing our reliance on fossil fuels. Efficient biomass production is essential to obtain large amounts of sustainable energy with minimal environmental cost. However, the biochemical and molecular processes behind the synthesis of the main components of biomass are still not fully understood. This review provides a comprehensive summary of the most relevant studies on cell wall biosynthesis and degradation mechanisms, focusing on the lignocellulosic component, in which the conversion process to fermentable sugars is expensive, due to its recalcitrant nature. A focus is placed on multi-omics research involving genomics, transcriptomics, proteomics, metabolomics, and phenomics, since multi-omics approaches offer a unique opportunity to investigate the biological pathways underlying the genotype traits characterizing cell wall energy crops. Furthermore, our study highlights the advances in genome editing approaches and proposes the modification of the genes that are involved in the complex cell wall structure as a feasible solution to an efficient biomass production. Several key points for future research activities based on these emerging technologies are also discussed, focusing on the combination of multi-omics and gene editing approaches, which offer potential for improved biomass valorization and the development of tangible bioproducts

Dudawalamides A−D, Antiparasitic Cyclic Depsipeptides from the Marine Cyanobacterium Moorea producens

HPLC. DudA family of 2,2-dimethyl-3-hydroxy-7-octynoic acid (Dhoya)-containing cyclic depsipeptides, named dudawalamides A−D (1−4), was isolated from a Papua New Guinean field collection of the cyanobacterium Moorea producens using bioassay-guided and spectroscopic approaches. The planar structures of dudawalamides A−D were determined by a combination of 1D and 2D NMR experiments and MS analysis, whereas the absolute configurations were determined by X-ray crystallography, modified Marfey’s analysis, chiral-phase GCMS, and chiral-phase awalamides A−D possess a broad spectrum of antiparasitic activity with minimal mammalian cell cytotoxicity. Comparative analysis of the Dhoya-containing class of lipopeptides reveals intriguing structure−activity relationship features of these NRPS−PKS-derived metabolites and their derivatives.HPLC. DudA family of 2,2-dimethyl-3-hydroxy-7-octynoic acid (Dhoya)-containing cyclic depsipeptides, named dudawalamides A−D (1−4), was isolated from a Papua New Guinean field collection of the cyanobacterium Moorea producens using bioassay-guided and spectroscopic approaches. The planar structures of dudawalamides A−D were determined by a combination of 1D and 2D NMR experiments and MS analysis, whereas the absolute configurations were determined by X-ray crystallography, modified Marfey’s analysis, chiral-phase GCMS, and chiral-phase awalamides A−D possess a broad spectrum of antiparasitic activity with minimal mammalian cell cytotoxicity. Comparative analysis of the Dhoya-containing class of lipopeptides reveals intriguing structure−activity relationship features of these NRPS−PKS-derived metabolites and their derivatives

Multi-trait analysis of post-harvest storage in rocket salad (Diplotaxis tenuifolia) links sensorial, volatile and nutritional data

AbstractRocket salad (Diplotaxis tenuifolia; wild rocket) is an important component of ready to eat salads providing a distinct peppery flavour and containing nutritionally relevant compounds. Quality deteriorates during post-harvest, in relation to time and storage temperature amongst other factors. Volatile organic compounds (VOCs) are easily measurable from rocket leaves and may provide useful quality indicators for e.g. changes in isothiocyanates derived from nutritionally important glucosinolates. VOC profiles discriminated storage temperatures (0, 5 and 10°C) and times (over 14days). More specifically, concentrations of aldehydes and isothiocyanates decreased with time paralleling a fall in vitamin C and a reduction in sensorial quality at the two higher temperatures. Sulphur containing compounds rise at later time-points and at higher temperatures coincident with an increase in microbial titre, mirroring a further drop in sensorial quality thus indicating their contribution to off-odours

Genetic microheterogeneity and phenotypic variation of Helicobacter pylori arginase in clinical isolates

BACKGROUND: Clinical isolates of the gastric pathogen Helicobacter pylori display a high level of genetic macro- and microheterogeneity, featuring a panmictic, rather than clonal structure. The ability of H. pylori to survive the stomach acid is due, in part, to the arginase-urease enzyme system. Arginase (RocF) hydrolyzes L-arginine to L-ornithine and urea, and urease hydrolyzes urea to carbon dioxide and ammonium, which can neutralize acid. RESULTS: The degree of variation in arginase was explored at the DNA sequence, enzyme activity and protein expression levels. To this end, arginase activity was measured from 73 minimally-passaged clinical isolates and six laboratory-adapted strains of H. pylori. The rocF gene from 21 of the strains was cloned into genetically stable E. coli and the enzyme activities measured. Arginase activity was found to substantially vary (>100-fold) in both different H. pylori strains and in the E. coli model. Western blot analysis revealed a positive correlation between activity and amount of protein expressed in most H. pylori strains. Several H. pylori strains featured altered arginase activity upon in vitro passage. Pairwise alignments of the 21 rocF genes plus strain J99 revealed extensive microheterogeneity in the promoter region and 3' end of the rocF coding region. Amino acid S232, which was I232 in the arginase-negative clinical strain A2, was critical for arginase activity. CONCLUSION: These studies demonstrated that H. pylori arginase exhibits extensive genotypic and phenotypic variation which may be used to understand mechanisms of microheterogeneity in H. pylori

Adiabaticity Conditions for Volatility Smile in Black-Scholes Pricing Model

Our derivation of the distribution function for future returns is based on the risk neutral approach which gives a functional dependence for the European call (put) option price, C(K), given the strike price, K, and the distribution function of the returns. We derive this distribution function using for C(K) a Black-Scholes (BS) expression with volatility in the form of a volatility smile. We show that this approach based on a volatility smile leads to relative minima for the distribution function ("bad" probabilities) never observed in real data and, in the worst cases, negative probabilities. We show that these undesirable effects can be eliminated by requiring "adiabatic" conditions on the volatility smile