648,561 research outputs found
Explicit birational geometry of 3-folds of general type, I
Let be a complex nonsingular projective 3-fold of general type. We prove
and for some positive
integer . A direct consequence is the birationality of the
pluricanonical map for all . Besides, the canonical
volume has a universal lower bound .Comment: 29 pages, Ann Sci Ecole Norm Sup (to appear
Phonological similarity effects in Cantonese word recognition
Two lexical decision experiments in Cantonese are described in which the recognition of spoken target words as a function of phonological similarity to a preceding prime is investigated. Phonological similaritv in first syllables produced inhibition, while similarity in second syllables led to facilitation. Differences between syllables in tonal and segmental structure had generally similar effects
Anti-ferrodistortive Nanodomains in PMN Relaxor
Temperature dependent studies of the 1/2(hk0) superlattice reflections \alpha
spots by synchrotron x-ray scattering measurements were performed in (PMN) and
(PMN-xPT) with Ti doping x<0.32 single crystals. Separation of the \alpha spots
from the underlying diffuse scattering background allowed studying them as
separate entities for the first time. Structure factor calculations have shown
that alpha spots constitute the presence of a new kind of anti-ferrodistortive
nanoregions (AFR) in the form of fluctuations produced by anti-parallel
short-range correlated Pb^2+ displacements. AFR appear to be different
and unrelated to the chemical nanodomains (CND) and ferroelectric polar
nanoregions (PNR). Simultaneous presence of AFR and PNR can explain relaxor
behavior as a result of competition between randomly occurring ferroelectric
and anti-ferroelectric fluctuations. Temperature dependence of the \alpha spots
in PMN showed a direct correlation with the freezing phase transition near
Tf~220 K.Comment: 10 pages, 7 figures, Conference-Fundamental Physics of Ferroelectrics
200
Longevity impact on life insurers in low interest rate environment
This paper aims at shedding some light on the interplay between two key risk factors affecting most life insurance products, namely biometric and investment risk. We enhance the pioneering model by Briys and de Varenne, featuring a stylized participating life insurance company by explicitly tying benefits to the survivorship of a cohort of policyholders. In particular, we allow for the two main components of biometric risk, that is systematic (longevity) risk and diversifiable (process) risk
Frustrated double ionization in two-electron triatomic molecules
Using a semi-classical model, we investigate frustrated double ionization
(FDI) in , a two-electron triatomic molecule, when driven by an
intense, linearly polarized, near-infrared (800 nm) laser field. We compute the
kinetic energy release of the nuclei and find a good agreement between
experiment and our model. We explore the two pathways of FDI and show that,
with increasing field strength, over-the-barrier ionization overtakes tunnel
ionization as the underlying mechanism of FDI. Moreover, we compute the angular
distribution of the ion fragments for FDI and identify a feature that can
potentially be observed experimentally and is a signature of only one of the
two pathways of FDI.Comment: 5 pages, 4 figure
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