Laser Phase and Frequency Stabilization Using Atomic Coherence

We present a novel and simple method of stabilizing the laser phase and frequency by polarization spectroscopy of an atomic vapor. In analogy to the Pound-Drever-Hall method, which uses a cavity as a memory of the laser phase, this method uses atomic coherence (dipole oscillations) as a phase memory of the transmitting laser field. A preliminary experiment using a distributed feedback laser diode and a rubidium vapor cell demonstrates a shot-noise-limited laser linewidth reduction (from 2 MHz to 20 kHz). This method would improve the performance of gas-cell-based optical atomic clocks and magnetometers and facilitate laser-cooling experiments using narrow transitions.Comment: 7 pages, 6 figures, appendix on the derivation of Eq.(3) (transfer function for a polarization-spectroscopy-based frequency discriminator) has been adde

Chemotherapeutic impact on pain and global health-related quality of life in hormone-refractory prostate cancer: Dynamically Modified Outcomes (DYNAMO) analysis of a randomized controlled trial.

PURPOSE: This paper applies the Dynamically Modified Outcomes (DYNAMO) model to a clinical trial of two chemotherapeutic regimens on global health-related quality of life (GHRQL) in hormone-refractory prostate cancer. METHODS: DYNAMO identifies the causal influences operating in a clinical trial and their mediation, moderation, and modulation by uncontrolled variables. The Southwest Oncology Group trial S9916 randomized assignment to mitoxantrone plus prednisone (M + P) versus docetaxel plus estramustine (D + E) treatments. In this application, we examine baseline-adjusted impacts of worst pain (McGill Pain Questionnaire) on GHRQL (EORTC Quality of Life Questionnaire-C30) at 10 weeks. RESULTS: The average treatment levels of pain did not differ, hence, the average mediated effect of treatment on GHRQL was zero. Nonetheless, M + P reduced the impact (the relational outcome) of pain on GHRQL by 54% relative to D + E. Individual variation in the relational outcome (modulation) was of the same magnitude as the average difference between the groups. Performance status moderated the direct effects of treatment, with D + E being more effective in good, but not poor, performance strata. CONCLUSIONS: The DYNAMO approach comprehensively accounted for treatment effects. Rather than a single average effect, there were three distinct treatment effects: one direct effect for each performance status level and a direct effect on the relationship between pain and GHRQL

Mass transfer of carbon dioxide across sea surfaces

The rate of mass transfer of carbon dioxide across the sea surface was investigated in the laboratory and at sea. In the laboratory, radioactive tracer techniques were employed using high specific activity C14O2. The equilibrium distribution of CO2 is not affected greatly and the mass transfer measured is very nearly the exchange coefficient...

Neutrino Mixing based on Mass Matrices with a 2↔32 \leftrightarrow 3 Symmetry

Under the assumption that the $2\leftrightarrow 3$ symmetry is broken only through phases, we give a systematical investigation of possible lepton mass matrix forms without referring to the explicit parameter values. The two types of the $2\leftrightarrow 3$ symmetry are investigated: one is that the left- and right-handed fields $(f_L, f_R)$ obey the symmetry, and another one is that only $f_L$ obeys the symmetry. In latter case, in spite of no $2\leftrightarrow 3$ symmetry in the Majorana mass matrix $M_R$ for $\nu_R$, the neutrino seesaw mass matrix still obey the $2\leftrightarrow 3$ symmetry. Possible phenomenologies are discussed.Comment: 12 pages, title and conclusions modifie

What Happens If an Unbroken Flavor Symmetry Exists?

Without assuming any specific flavor symmetry and/or any specific mass matrix forms, it is demonstrated that if a flavor symmetry (a discrete symmetry, a U(1) symmetry, and so on) exists, we cannot obtain the CKM quark mixing matrix $V$ and the MNS lepton mixing matrix $U$ except for those between two families for the case with the completely undegenerated fermion masses, so that we can never give the observed CKM and MNS mixings. Only in the limit of $m_{\nu 1} =m_{\nu 2}$ ($m_d=m_s$), we can obtain three family mixing with an interesting constraint $U_{e3}=0$ ($V_{ub}=0$).Comment: 10 pages, no figure, title and presentation change

Twist glass transition in regioregulated poly(3-alkylthiophenes)s

The molecular structure and dynamics of regioregulated poly(3-butylthiophene) (P3BT), poly(3-hexylthiophene)(P3HT), and poly(3-dodecylthiophene) (P3DDT) were investigated using Fourier transform infrared absorption (FTIR), solid state $^{13}$C nuclear magnetic resonance (NMR), and differential scanning calorimetry (DSC) measurements. In the DSC measurements, the endothermic peak was obtained around 340 K in P3BT, and assigned to enthalpy relaxation that originated from the glass transition of the thiophene ring twist in crystalline phase from results of FTIR, $^{13}$C cross-polarization and magic-angle spinning (CPMAS) NMR, $^{13}$C spin-lattice relaxation time measurements, and centerband-only detection of exchange (CODEX) measurements. We defined this transition as {\it twist-glass transition}, which is analogous to the plastic crystal - glassy crystal transition.Comment: 9 pages, 10 figures, 2 tables. Phys.Rev.B, in pres

Modeling Noise Coupling from Non-Parallel PCB Trace Routing

Coupling between PCB signal traces in proximity is of concern to PCB designers and EMC engineers. The behavior of noise coupling between non-parallel microstrip lines is studied in this paper by a full-wave numerical modeling method CEMPIE, designating a circuit extraction approach based on a mixed-potential integral equation formulation. Good agreement between the numerical results and measurements was obtained