On Non-tachyonic Z_N x Z_M Orientifolds of Type 0B String Theory

We study open descendants of four dimensional Z_N x Z_M orbifolds of the non-supersymmetric type 0B string theory. An exhaustive analysis shows, that using the crosscap constraint the only model for which one can project out the tachyon is the Z_2 x Z_2 orbifold. For this case we explicitly construct the open string amplitudes. The gauge group corresponding to the various inequivalent Klein bottle projections turns out to be either symplectic or unitary.Comment: 15 pages, harvma

Influence of liquid surface tension (surfactants) on bubble formation at rigid and flexible orifices

The influence of liquid surface tension on the bubble formation from both rigid and flexible orifice has been investigated. The liquid phases under test are aqueous solutions with butanol or surfactants (cationic, non-ionic and anionic); static and dynamic measurements of liquid surface tension have been performed to characterise them. This study shows that the effect of surface tension on the bubbles generated cannot be analysed only in terms of the static surface tension, but also depends on whether the bubbles are generated from a rigid orifice or from a flexible orifice. The kinetics of adsorption and diffusion of the solute molecules towards the bubble interface have to be taken into account insofar as their time scales are comparable to those of the bubble formation phenomenon

Effect of surfactants on liquid side mass transfer coefficients

In the present paper, the effect of liquid properties (surfactants) on bubble generation phenomenon, interfacial area and liquid side mass transfer coefficient was investigated. The measurements of surface tension (static and dynamic methods), of Critical Micelle Concentration (CMC) and of characteristic adsorption parameters such as the surface coverage ratio at equilibrium (se) were performed to understand the effects of surfactants on the mass transfer efficiency. Tap water and aqueous solutions with surfactants (cationic and anionic) were used as liquid phases and an elastic membrane with a single orifice as gas sparger. The bubbles were generated into a small-scale bubble column. The local liquid side mass transfer coefficient (kL) was obtained from the volumetric mass transfer coefficient (kLa) and the interfacial area (a) was deduced from the bubble diameter (DB), the bubble frequency (fB) and the terminal bubble rising velocity (UB). Only the dynamic bubble regime was considered in this work (ReOR = 150 - 1000 and We = 0.002 - 4). This study has clearly shown that the presence of surfactants affects the bubble generation phenomenon and thus the interfacial area (a) and the different mass transfer parameters, such as the volumetric mass transfer coefficient (kLa) and the liquid-side mass transfer coefficient (kL). Whatever the operating conditions, the new kLa determination method has provided good accuracy without assuming that the liquid phase is perfectly mixed as in the classical method. The surface coverage ratio (se) proves to be crucial for predicting the changes of kL in aqueous solutions with surfactants

Idiosyncrasy as an explanation for power laws in nature

Complex systems theory pays much attention to simple mechanisms producing nontrivial patterns, especially power laws. However, power laws with exponent close to one also result from complex mixtures of mechanisms that, in isolation, would not necessarily give this type of distribution. Probably, both paths to the power law are relevant in nature. The second gives a plausible explanation for some instances of power laws emerging in extremely complex systems, such as ecosystems.Comment: To be published in Trends in Mathematics. 6 pages, 0 figure

Optical parametric generation in periodically poled KTiOPO4 via extended phase matching

We report an experimental demonstration of optical parametric generation in a periodically poled KTiOPO4 crystal based on the principle of mirrorless optical parametric oscillation. A femtosecond pump pulse spectrally centered at 792 nm from a Ti:sapphire amplifier is prechirped to minimize Kerr effects. The pump pulse is then injected into the nonlinear crystal and down converted to signal and idler pulses, approximately centered at 1584 nm, via amplified spontaneous parametric down conversion in a copropagating type-II quasiphase matching configuration. The maximum internal downconversion efficiency is 43%, the highest ever reported for optical parametric generators based on KTiOPO4 crystals. Such a device may find applications in optical signal processing and biological imaging

Bilateral triad of persistent median artery, a bifid median nerve and high origin of its palmar cutaneous branch. A case report and clinical implications

We report the association of a persistent median artery, a bifid median nerve with a rare very high origin palmar cutaneous branch, presenting bilaterally in the upper limb of a 75-year-old female cadaver. The persistent median nerve with a bifid median nerve has been reported in patients presenting with carpal tunnel syndrome. Reports of this neurovascular anomaly occurring in association with a high origin palmar cutaneous branch however, are few. This subset of patients is at risk of inadvertent nerve transection during forearm and wrist surgery. Pre-operative magnetic resonance imaging (MRI) and high resolution sonography (HRS) can be used to screen this triad. MRI can reveal if the patient’s disability is associated with a persistent median nerve, a bifid median nerve. HRS can help identify a palmar cutaneous branch of the median nerve that arises in an unexpected high forearm location. Such knowledge will help surgeons in selecting the most appropriate surgical procedure, and help avoid inadvertent injury to cutaneous nerves arising in unexpected locations. In patients presenting with a bilateral carpal tunnel syndrome, hand surgeons should consider very high on the list of differential diagnosis a persistent median artery with a concomitant bifid median nerve, with a high suspicion of a possible bilateral occurrence of a bilaterally high arising palmar cutaneous branch of the median nerve. © 2016, Universidad de la Frontera. All rights reserved

Ramifications of intranuclear re-scattering in MINOS

MINOS will measure the composition of a neutrino beam at two locations, 735km apart, in an effort confirm the (atmospheric) neutrino oscillation hypothesis and measure the associated mixing parameters. Oscillations will be manifested as a difference in the rate and energy spectrum of muon neutrino CC interactions measured in the two detectors. Because most interactions observed in MINOS are inelastic, the neutrino energy is reconstructed as the sum of the energy carried by the muon and that seen in the hadronic shower emanating from the struck nucleus. The latter is sensitive to uncertainties in the hadronisation process, chief among them those due to intranuclear re-scattering (i.e., final state interactions). We discuss the simulation of intranuclear re-scattering currently used by MINOS and its effect on quantities observable in the experiment.Comment: 6 pages, 5 figures, To be published in Nucl.Phys.Proc.Suppl.-- Proceedings of the IV International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region, 26-29, September, 200

Evidence for narrow resonant structures at W≈1.68W \approx 1.68 and W≈1.72W \approx 1.72 GeV in real Compton scattering off the proton

First measurement of the beam asymmetry $\Sigma$ for Compton scattering off the proton in the energy range $E_{\gamma}=0.85 - 1.25$ GeV is presented. The data reveals two narrow structures at $E_{\gamma}= 1.036$ and $E_{\gamma}=1.119$ GeV. They may signal narrow resonances with masses near $1.68$ and $1.72$ GeV, or they may be generated by the sub-threshold $K\Lambda$ and $\omega p$ production. Their decisive identification requires additional theoretical and experimental efforts.Comment: Published versio

MoS2-HgTe Quantum Dot Hybrid Photodetectors beyond 2 μm

Mercury telluride (HgTe) colloidal quantum dots (CQDs) have been developed as promising materials for the short and mid-wave infrared photodetection applications because of their low cost, solution processing and size tunable absorption in the short wave- and mid- infrared spectrum. However, the lowmobility and poor photo-gain have limited the responsivity of HgTe CQDs-based photodetectors to only tens of mA/W. Here, we integrated HgTe CQDs on a TiO2 encapsulated MoS2 transistor channel to form hybrid phototransistors with high responsivity of ~106 A/W, the highest reported to date for HgTe QDs. By operating the phototransistor in the depletion regime enabled by the gate modulated current of MoS2, the noise current is significantly suppressed leading to an experimentally measured specific detectivity D* of ~1012 Jones at a wavelength of 2 μm. This work demonstrates for the first time the potential of the hybrid 2D/QD detector technology in reaching out to wavelengths beyond 2 μm with compelling sensitivity.Peer ReviewedPostprint (author's final draft

Antibody localization in horse, rabbit, and goat antilymphocyte sera

The localization of antibodies was studied in rabbit, goat, and horse ALS raised by weekly immunization with canine or human spleen cells for 4 to 12 weeks. A combination of analytic techniques was used including column chromatography, electrophoresis, immunoelectrophoresis, determination of protein concentration, and measurement of antibody titers. In the rabbit and goat ALS, virtually all of the leukoagglutinins and lymphocytotoxins were in the easily separable IgG; accidentally induced thromboagglutinins were in the same location. In the rabbit hemagglutinins were found in both the IgG and IgM, whereas in the goat these were almost exclusively in the IgM. The antiwhite cell antibodies were most widely distributed in the horse. The cytotoxins were primarily in the IgG, but the leukoagglutinins were most heavily concentrated in the T-equine globulin which consists mostly of IgA. By differential ammonium sulfate precipitation of a horse antidoglymphocyte serum, fractions were prepared that were rich in IgG and IgA. Both were able to delay the rejection of canine renal homografts, the IgA-rich preparation to a somewhat greater degree. The findings in this study have been discussed in relation to the refining techniques that have been used for the production of globulin from heterologous ALS. © 1970