Epsilon production in a geometrical approach

In a previous paper ε production was studied, by making used of dual properties, and it was qualitatively shown that pion exchange dominates near the forward direction and there is a small exchange with the A₁ quantum numbers. This is confirmed by the polarization data, since it clearly shows that two independent amplitudes are essential in this reaction. Duality also provides a guidance for the position of the zeros of the imaginary parts of these amphtudes. In this note we shall take over this problem again and quantitatively show that the dual predictions are in agreement with the experimental data.Facultad de Ciencias Exacta

Assessment of plasma chitotriosidase activity, CCL18/PARC concentration and NP-C suspicion index in the diagnosis of Niemann-Pick disease type C: A prospective observational study

Background: Niemann-Pick disease type C (NP-C) is a rare, autosomal recessive neurodegenerative disease caused by mutations in either the NPC1 or NPC2 genes. The diagnosis of NP-C remains challenging due to the non-specific, heterogeneous nature of signs/symptoms. This study assessed the utility of plasma chitotriosidase (ChT) and Chemokine (C-C motif) ligand 18 (CCL18)/pulmonary and activation-regulated chemokine (PARC) in conjunction with the NP-C suspicion index (NP-C SI) for guiding confirmatory laboratory testing in patients with suspected NP-C. Methods: In a prospective observational cohort study, incorporating a retrospective determination of NP-C SI scores, two different diagnostic approaches were applied in two separate groups of unrelated patients from 51 Spanish medical centers (n = 118 in both groups). From Jan 2010 to Apr 2012 (Period 1), patients with =2 clinical signs/symptoms of NP-C were considered ''suspected NP-C'' cases, and NPC1/NPC2 sequencing, plasma chitotriosidase (ChT), CCL18/PARC and sphingomyelinase levels were assessed. Based on findings in Period 1, plasma ChT and CCL18/PARC, and NP-C SI prediction scores were determined in a second group of patients between May 2012 and Apr 2014 (Period 2), and NPC1 and NPC2 were sequenced only in those with elevated ChT and/or elevated CCL18/PARC and/or NP-C SI =70. Filipin staining and 7-ketocholesterol (7-KC) measurements were performed in all patients with NP-C gene mutations, where possible. Results: In total across Periods 1 and 2, 10/236 (4%) patients had a confirmed diagnosis o NP-C based on gene sequencing (5/118 4.2%] in each Period): all of these patients had two causal NPC1 mutations. Single mutant NPC1 alleles were detected in 8/236 (3%) patients, overall. Positive filipin staining results comprised three classical and five variant biochemical phenotypes. No NPC2 mutations were detected. All patients with NPC1 mutations had high ChT activity, high CCL18/PARC concentrations and/or NP-C SI scores =70. Plasma 7-KC was higher than control cut-off values in all patients with two NPC1 mutations, and in the majority of patients with single mutations. Family studies identified three further NP-C patients. Conclusion: This approach may be very useful for laboratories that do not have mass spectrometry facilities and therefore, they cannot use other NP-C biomarkers for diagnosis

Asymptotic analysis of axisymmetric drop spreading

We study in this paper the time evolution of the spreading process of a small drop in contact with a flat dry surface, using asymptotic techniques. We reduced the problem by solving a quasisteady self-similar macroscopic problem and matched with the precursor region solution, where the van der Waals forces are important. A final nonlinear third-order ordinary differential equation has been solved numerically using shooting methods based on the fourth-order Runge-Kutta techniques. We obtained how the capillary number changes when the drop size decreases with time. The evolution process then diverges slightly from that obtained using the spherical cap approximation. The influence of gravity is also considered for both hanging and sitting drops. [S1063-651X(98)09409-4]

Is α′\alpha' also the e±e\pm annihilation scale ?

A model for the annihilation of electron-positron pairs into hadrons for q/sup 2/=s>4 GeV/sup 2/ and up to the highest measured energies is developed. The main ingredients are point-like couplings between three resonances and photons and the high level of opening thresholds that follows from an effective Lagrangian formalism. The model gives an almost constant annihilation cross section, soft pions everywhere and at all energies, high multiplicities and a large absolute cross section. The details of all exclusive channels are also predicted. Other consequences of this point of view concern the discovery of hitherto ignored couplings in three resonances and photons and the high level of opening threshold that follows from an effective Lagrangian formalism. The model gives an almost constant annihilation cross section, soft pions everywhere and at all energies, high multiplicities and a large absolute crosssection. The details of all exclusive channels are also predicted. Other consequences of this point of view concern the discovery of hitherto ignored couplings in low-energy photon initiated reactions. It is argued that the energy regime explored by SPEAR is not the asymptopia and possible further constancy of the cross section in a range of s is discussed. (4 refs)

Phenomenological study of high-energy exchanges based on multiperipheral ideas

The study presented is based on the empirical observation that typical P'-pole parametrizations in the intermediate energy range reproduce, in the global duality sense, the combinations of total elastic cross- sections with the quantum numbers of the vacuum in the crossed channel. (13 refs)