Faithful actions from hyperplane arrangements

We show that if X is a smooth quasiprojective 3–fold admitting a flopping contraction, then the fundamental group of an associated simplicial hyperplane arrangement acts faithfully on the derived category of X. The main technical advance is to use torsion pairs as an efficient mechanism to track various objects under iterations of the flop functor (or mutation functor). This allows us to relate compositions of the flop functor (or mutation functor) to the theory of Deligne normal form, and to give a criterion for when a finite composition of 3–fold flops can be understood as a tilt at a single torsion pair. We also use this technique to give a simplified proof of a result of Brav and Thomas (Math. Ann. 351 (2011) 1005–1017) for Kleinian singularities

Geschmack- und gesundheitsrelevante Qualität von ökologisch angbauten Äpfeln: Eine 3jährige Feldvergleichsstudie mit standard- und ganzheitlichen Untersuchungsmethoden

In a 3 years lasting field study with the ‘Golden Delicious’ cultivar, we compared fruits of 5 pairs of organic/integrated fruit farms. The orchards were similar in microclimate, soil conditions and planting system. To assess inner fruit quality we investigated at the beginning and at the end of cold storage: (i) standard parameters (firmness, sugar, malic acid., mineral content); (ii) sensorial quality by panel tests; (iii) health related components (23 phenolic compounds, nutritional fibres; vitamins); and (v) fruit «vitality quality» by holistic approaches (crystallisation in copper chloride, self degradation tests, feeding preference tests with laboratory rats). The most significant differences were found in year one of the study, and were by tendency confirmed in the following two years. In year one all fruit samples of organic orchards had significantly firmer fruit flesh (14%), a 10 % higher index of inner quality (on basis of sugar and malic acid content and fruit flesh firmness), and 15% higher taste scores than conventional ones. Phosphorus content of the fruit flesh was 31% higher in organic apples and closely correlated (r2 = 0.93) with the index of inner quality and sensory score (r2 = 0.69). No extraction method of Phosphorus in the soil (water, NH4-EDTA, citric acid, CAL) correlated with the P-content in the fruits. However, P in the fruit flesh correlated by r2 = 0.72 with the microbial activity of the soil expressed as the ratio of microbialbound Nitrogen and Carbon in the soil. With a value of 3.85 the Cmic:Nmic ratio was 44.5 % lower (thus more favourable) in organic tree strips. Flavanols, with 65.7 % of the total polyphenol content were the dominant group of polyphenols. The content of flavonols was 22.7 % higher in organic apples in the first year and 15.6 % in the average of the three years. The self-degradation test didn't provide significant differences. Laboratory rats, showed a tendency to prefer IP apples probably due to their advanced ripeness. Thus rat behaviour did not correspond with the sensory panel judgement. The picture forming method provided a correct reproducibility with repeated blind samples before and after storage (r2 = 0.83), and distinguished 100 % correctly organic an IP fruit in the first year. In the second year there was one miss qualification. The average value over three dates of the index for «vitality quality», which was especially created for this study, was 44.6 % higher with organic apples The picture forming methods correlated well with sensory scores and standard quality (r2 = 0.63) in the first year. The study revealed interesting and consumer-relevant differences between organic and integrated apples with standard and holistic methods

Fixed-Point Analysis of the Low-Energy Constants in the Pion-Nucleon Chiral Lagrangian

In the framework of heavy-baryon chiral perturbation theory, we investigate the fixed point structure of renormalization group equations (RGE) for the ratios of the renormalized low energy constants (LECs) that feature in the pion-nucleon chiral Lagrangian. The ratios of the LECs deduced from our RGE analysis are found to be in semi-quantitative agreement with those obtained from direct fit to the experimental data. The naturalness of this agreement is discussed using a simple dimensional analysis combined with Wilsonian RGEs.Comment: 10 page

A real time spectrum to dose conversion system

A system has been developed which permits the determination of dose in real time or near real time directly from the pulse-height output of a radiation spectrometer. The technique involves the use of the resolution matrix of a spectrometer, the radiation energy-to-dose conversion function, and the geometrical factors, although the order of matrix operations is reversed. The new technique yields a result which is mathematically identical to the standard method while requiring no matrix manipulations or resolution matrix storage in the remote computer. It utilizes only a single function for each type dose required and each geometric factor involved

Cholesterol levels affect the performance of aunps-decorated thermo-sensitive liposomes as nanocarriers for controlled doxorubicin delivery

Stimulus-responsive liposomes (L) for triggering drug release to the target site are particularly useful in cancer therapy. This research was focused on the evaluation of the effects of cholesterol levels in the performance of gold nanoparticles (AuNPs)-functionalized L for controlled doxorubicin (D) delivery. Their interfacial and morphological properties, drug release behavior against temperature changes and cytotoxic activity against breast and ovarian cancer cells were studied. Langmuir isotherms were performed to identify the most stable combination of lipid components. Two mole fractions of cholesterol (3.35 mol% and 40 mol%, L1 and L2 series, respectively) were evaluated. Thin-film hydration and transmembrane pH-gradient methods were used for preparing the L and for D loading, respectively. The cationic surface of L allowed the anchoring of negatively charged AuNPs by electrostatic interactions, even inducing a shift in the zeta potential of the L2 series. L exhibited nanometric sizes and spherical shape. The higher the proportion of cholesterol, the higher the drug loading. D was released in a controlled manner by diffusion-controlled mechanisms, and the proportions of cholesterol and temperature of release media influenced its release profiles. D-encapsulated L preserved its antiproliferative activity against cancer cells. The developed liposomal formulations exhibit promising properties for cancer treatment and potential for hyperthermia therapy.Ministerio de Ciencia e Innovación CTQ2014- 57515-C2-

Classification of the invariants of foliations by curves of low degree on the three-dimensional projective space

We study foliations by curves on the three-dimensional projective space with no isolated singularities, which is equivalent to assuming that the conormal sheaf is locally free. We provide a classification of the topological and algebraic invariants of the conormal sheaves and singular schemes for such foliations by curves, up to degree 3. In particular, we prove that foliations by curves of degree 1 or 2 are contained in a pencil of planes or are Legendrian, and are given by the complete intersection of two codimension one distributions. Furthermore, we prove that the conormal sheaf of a foliation by curves of degree 3 with reduced singular scheme either splits as a sum of line bundles or is an instanton bundle. For degree larger than 3, we focus on two classes of foliations by curves, namely Legendrian foliations and those whose conormal sheaf is a twisted null-correlation bundle. We give characterizations of such foliations, describe their singular schemes and their moduli spaces

Large-n Critical Behavior of O(n)xO(m) Spin Models

We consider the Landau-Ginzburg-Wilson Hamiltonian with O(n)x O(m) symmetry and compute the critical exponents at all fixed points to O(n^{-2}) and to O(\epsilon^3) in a \epsilon=4-d expansion. We also consider the corresponding non-linear sigma model and determine the fixed points and the critical exponents to O(\tilde{\epsilon}^2) in the \tilde{\epsilon}=d-2 expansion. Using these results, we draw quite general conclusions on the fixed-point structure of models with O(n)xO(m) symmetry for n large and all 2 < d < 4.Comment: 29 pages, a few refs added, Nucl. Phys. B in pres

High-temperature expansion of the one-loop effective action induced by scalar and Dirac particles

The complete nonperturbative expressions for the high-temperature expansion of the one-loop effective action induced by the charged scalar and the charged Dirac particles both at zero and finite temperatures are derived with account for possible nontrivial boundary conditions. The background electromagnetic field is assumed to be stationary and such that the corresponding Klein-Gordon operator or the Dirac Hamiltonian are self-adjoint. The contributions of particles and antiparticles are obtained separately. The explicit expressions for the $C$-symmetric and the non $C$-symmetric vacuum energies of the Dirac fermions are derived. The leading corrections to the high-temperature expansion due to the nontrivial boundary conditions are explicitly found. The corrections to the logarithmic divergence of the effective action that come from the boundary conditions are derived. The high-temperature expansion of the naive one-loop effective action induced by charged fermions turns out to be divergent in the limit of a zero fermion mass.Comment: 24 pp; correct normalization condition used, some misprints correcte

A method of calculating the performance of controllable propellers with sample computations

This paper contains a series of calculations showing how the performance of controllable propellers may be derived from data on fixed-pitch propellers given in N.A.C.A. Technical Report No. 350, or from similar data. Sample calculations are given which compare the performance of airplanes with fixed-pitch and with controllable propellers. The gain in performance with controllable propellers is shown to be largely due to the increased power available, rather than to an increase in efficiency. Controllable propellers are of particular advantage when used with geared and with supercharged engines. A controllable propeller reduces the take-off run, increases the rate of climb and the ceiling, but does not increase the high speed, except when operating above the design altitude of the previously used fixed-pitch propeller or when that propeller was designed for other than high speed