Neutrinos as cosmic messengers

I briefly review the current status of neutrino oscillation parameters and discuss the role of neutrinos as cosmological probes, that could possibly induce the baryon asymmetry as well as the dark matter in the Universe. I comment on the origin of neutrino masses in seesaw-type and low-scale models and mention some of their laboratory signals.Comment: 14 pages AIP proceedings of 4th International Workshop on the Dark Side of the Universe (DSU08) Conference, Cairo, macros included, 20 figure files, 13 figure

A possible supersymmetric solution to the discrepancy between B -> \phi K_S and B -> \eta' K_S CP asymmetries

We present a possible supersymmetric solution to the discrepancy between the observed mixing CP asymmetries in B -> \phi K_S and B -> \eta' K_S. We show that due to the different parity in the final states of these processes, their supersymmetric contributions from the R-sector have an opposite sign, which naturally explain the large deviation between S_{\phi K_S} and S_{\eta' K_S}. We also consider the proposed mechanisms to solve the puzzle of the observed large branching ratio of B -> \eta' K and study their impact on S_{eta' K_S}.Comment: 4 pages, 2 figure

Ordering dynamics in the voter model with aging

The voter model with memory-dependent dynamics is theoretically and numerically studied at the mean-field level. The `internal age', or time an individual spends holding the same state, is added to the set of binary states of the population, such that the probability of changing state (or activation probability $p_i$) depends on this age. A closed set of integro-differential equations describing the time evolution of the fraction of individuals with a given state and age is derived, and from it analytical results are obtained characterizing the behavior of the system close to the absorbing states. In general, different age-dependent activation probabilities have different effects on the dynamics. When the activation probability $p_i$ is an increasing function of the age $i$, the system reaches a steady state with coexistence of opinions. In the case of aging, with $p_i$ being a decreasing function, either the system reaches consensus or it gets trapped in a frozen state, depending on the value of $p_\infty$ (zero or not) and the velocity of $p_i$ approaching $p_\infty$. Moreover, when the system reaches consensus, the time ordering of the system can be exponential ($p_\infty>0$) or power-law like ($p_\infty=0$). Exact conditions for having one or another behavior, together with the equations and explicit expressions for the exponents, are provided

Lepton-Flavor Violation with Non-universal Soft Terms

We study the lepton-flavor violation processes tau ->mu gamma and mu->e gamma in two different examples of models with non-universal soft breaking terms derived from strings. We show that the predictions are quite different from those of universal scenarios. Non-universal A-terms provide an interesting framework to enhance the supersymmetric contributions to CP violation effects. We observe that in the case of the lepton-flavor violation we study, the non-universality of the scalar masses enhances the branching ratios more significantly than the non-universality of the A-terms. We find that the current experimental bounds on these processes restrict both the parameter space of the models and the texture of the Yukawa couplings which predicts the lepton masses, providing at the same time an interesting experimental test for physics beyond the Standard Model.Comment: 15 pages, 6 figures minor change

Loss Dependence on Geometry and Applied Power in Superconducting Coplanar Resonators

The loss in superconducting microwave resonators at low-photon number and low temperatures is not well understood but has implications for achievable coherence times in superconducting qubits. We have fabricated single-layer resonators with a high quality factor by patterning a superconducting aluminum film on a sapphire substrate. Four resonator geometries were studied with resonant frequencies ranging from 5 to 7 GHz: a quasi-lumped element resonator, a coplanar strip waveguide resonator, and two hybrid designs that contain both a coplanar strip and a quasi-lumped element. Transmitted power measurements were taken at 30 mK as a function of frequency and probe power. We find that the resonator loss, expressed as the inverse of the internal quality factor, decreases slowly over four decades of photon number in a manner not merely explained by loss from a conventional uniform spatial distribution of two-level systems in an oxide layer on the superconducting surfaces of the resonator.Comment: 4 pages, 5 figures, Submitted to ASC 2010 conference proceeding

Quaternary alkaloids of the stem and root bark of Hunteria eburnea Pichon

The object of this study was the isolation and elucidation of the structure of unknown quaternary alkaloids occurring in the stem and root bark of Hunteria eburnea Pichon. We succeeded in isolating ten quaternary bases, the structure of five of which have been elucidated and makes the subject of this thesis. The isolation and separation of the alkaloids were extremely difficult and time consuming especially the chromatography on cellulose columns. Hunterburnine α- and β-methochlorides have been easily identified according to their published physical constants since they have been reported to occur in different plants. We isolated a quaternary salt and for which we propose the structure as 21 -methoxyhunterbumine methochloride. Another pair of quaternary alkaloids belonging to the same skeletal type as hunterburnine has been isolated. One being desoxyhunterburnine α-methochloride which we called antirhine α-methochloride, the second being its dihydro derivative occurring naturally and could be easily prepared from antirhine α-methochloride by hydrogenation. The striking feature in this pair of bases is the α-configuration of the N⁺-CH₃ groups. By déméthylation and subsequent méthylation of the resulting tertiary bases, only the β-isomers were obtained. We isolated for the first time from this plant Pleiocarpamine methods lor ide and this is contrary to the proposal of W.I. Taylor that none of the quaternary alkaloids of Hunteria eburnea originates from the co-occurring tertiary base. Pleiocarpamine has previously been reported to occur in this plant. Yohimbol, Huntrabrine and Akuammicine methochlorides have been easily identified mainly by spectroscopic methods. The final quaternary alkaloid was difficult to attack by the conventional chemical methods for elucidation of structure. We have proposed a structure which has been confirmed by X-ray analysis. Hunteracine nitrogen being at represents a new structural class where the quaternary the junction of three rings does not bear an alkyl group.Montréal Trigonix inc. 201

Changes in the mechanical behavior of Nitinol following variations of heat treatment duration and temperature

The successful use of Nickel-Titanium (Nitinol) in biomedical applications requires an accurate control of its unique mechanical properties. The purpose of this study is to analyze the effects of a wide range of heat treatments on the mechanical behavior of hot-rolled and cold-drawn Nitinol. Results comprise an understanding of the effect of heat treatment temperature and time variation on final material response which is imperative for optimization of material properties. Thirty-three heat treatment variations are tested by combining three durations, 10 minutes, 90 minutes, and 8 hours, with eleven different heat treatment temperatures between 200°C and 440°C. Following heat treatment, the Nitinol samples undergo tensile testing with upper plateau strength, lower plateau strength, ultimate tensile strength, strain to failure, and residual elongation compared for all test groups. Heat treatment "power" is used to describe the efficacy of different combinations of heat treatment temperature and duration. When using hot-rolled Nitinol, results show a low heat treatment power does not create significant precipitation hardening or a significant decrease in martensite transformation stress, resulting in a high upper plateau strength, high residual strain values, and evidence of plastic deformation upon unloading. Moderate power treatments lead to sufficient hardening of the material and a decrease in martensite transformation stress resulting in a pseudoelastic response. Increasing to a high treatment power further decreases the transformation stress and increases the martensite transformation temperature leading to a shape-memory response in hot rolled Nitinol. When using cold-drawn Nitinol, low and moderate heat treatment power levels result in the material exhibiting a pseudoelastic response. Increasing heat treatment power shows the same effects on martensite transformation stress and temperature as seen with the hot-rolled material resulting in a material response transition from pseudoelastic to shape memory.M.S.Committee Chair: Gall, Kenneth; Committee Member: McDowell, David; Committee Member: Thadhani, Nares

Aerial Trespass and the Fourth Amendment

Since 1973, courts have analyzed aerial surveillance under the Fourth Amendment by applying the test from Katz v. United States, which states that a search triggers the Fourth Amendment when a government actor violates a person’s “reasonable expectation of privacy.” The Supreme Court applied Katz to aerial surveillance three times throughout the 1980s, yet this area of the law remains unsettled and outcomes are unpredictable. In 2012, the Supreme Court recognized an alternative to the Katz test in Jones v. United States, which held that a search triggers the Fourth Amendment when a government actor physically intrudes into a constitutionally protected space with the intent to obtain information. Courts have largely avoided applying the Jones intrusion test to aerial surveillance. This Note explores the intersection of the Fourth Amendment, aerial property rights, and government use of drones. It argues that the Jones intrusion test can be a useful doctrinal tool for analyzing aerial surveillance under the Fourth Amendment. This issue will only grow in importance as law enforcement expands its use of use of drone technology