Femtosecond real-time probing of reactions. XI. The elementary OClO fragmentation

Femtosecond reaction dynamics of OClO in a supersonic molecular beam are reported. The system is excited to the A 2A2 state with a femtosecond pulse, covering a range of excitation in the symmetric stretch between v1=17 to v1=11 (308–352 nm). A time-delayed femtosecond probe pulse ionizes the OClO, and OClO + is detected. This ion has not been observed in previous experiments because of its ultrafast fragmentation. Transients are reported for the mass of the parent OClO as well as the mass of the ClO. Apparent biexponential decays are observed and related to the fragmentation dynamics: OClO+hnu-->(OClO)[double-dagger]*-->ClO+O -->Cl+O2 . Clusters of OClO with water (OClO)n (H2O)m with n from 1 to 3 and m from 0 to 3 are also observed. The dynamics of the fragmentation reveal the nuclear motions and the electronic coupling between surfaces. The time scale for bond breakage is in the range of 300–500 fs, depending on v1; surface crossing to form new intermediates is a pathway for the two channels of fragmentation: ClO+O (primary) and Cl+O2 (minor). Comparisons with results of ab initio calculations are made

Symbol synchronization in convolutionally coded systems

Alternate symbol inversion is sometimes applied to the output of convolutional encoders to guarantee sufficient richness of symbol transition for the receiver symbol synchronizer. A bound is given for the length of the transition-free symbol stream in such systems, and those convolutional codes are characterized in which arbitrarily long transition free runs occur

Unequal civic development? Vocational tracking and civic outcomes in Germany

Vocational education and training (VET) is a common form of upper secondary school tracking in countries around the world. There are ongoing debates regarding the effects of this differentiation on academic and labor market outcomes; however, evidence on civic outcomes is lacking. Using a unique cohort study in Germany ( N = 2461) and a doubly robust weighting approach with a rich set of baseline covariates to address selection bias, we estimated the effects of VET (relative to academic upper secondary school) on political interest, internal political efficacy, and intent to vote across 15 years of late adolescence and early adulthood. We estimated negative effects of VET on these civic outcomes, particularly as participants grew older. Implications for future research and VET policy are discussed

The Outcome of Patients with Melanoma Is Not Associated with the Time Point of Lymphatic Mapping with Respect to Excisional Biopsy of the Primary Tumor

Background: Sentinel lymph node biopsy (SLNB) has become the standard care for melanoma and is an important diagnostic procedure. It has been doubted whether lymphoscintigraphy detects the correct sentinel lymph node (SLN) when excision of the tumor and SLNB are not performed at the same time. This would imply that this sequential approach may have an increased risk of undetected micrometastases resulting in a worse outcome. Objective: The purpose of the present study was to compare the outcome of melanoma patients having received excision of the tumor and SLNB either at the same time or consecutively. Methods: A total of 854 patients with cutaneous melanoma were enrolled in this retrospective study between September 1996 and November 2007. Disease-free (DFS) and overall survivals (OS) were estimated using the Kaplan-Meier product limit method and were analyzed by the log rank test. Results: No statistically significant difference was found regarding DFS, progression rates and OS in patients with primary tumor excision and SLNB at the same time compared with patients with excisional biopsy of primary tumor and SLNB at different times. Conclusion: These data suggest that excisional biopsy of the primary tumor does not prevent the correct SLN mapping in melanoma patients. Copyright (C) 2010 S. Karger AG, Base

Complete Solving for Explicit Evaluation of Gauss Sums in the Index 2 Case

Let $p$ be a prime number, $q=p^f$ for some positive integer $f$, $N$ be a positive integer such that $\gcd(N,p)=1$, and let \k be a primitive multiplicative character of order $N$ over finite field \fq. This paper studies the problem of explicit evaluation of Gauss sums in "\textsl{index 2 case}" (i.e. f=\f{\p(N)}{2}=[\zn:\pp], where \p(\cd) is Euler function). Firstly, the classification of the Gauss sums in index 2 case is presented. Then, the explicit evaluation of Gauss sums G(\k^\la) (1\laN-1) in index 2 case with order $N$ being general even integer (i.e. N=2^{r}\cd N_0 where $r,N_0$ are positive integers and $N_03$ is odd.) is obtained. Thus, the problem of explicit evaluation of Gauss sums in index 2 case is completely solved