1,168 research outputs found
Efficient estimation of Banach parameters in semiparametric models
Consider a semiparametric model with a Euclidean parameter and an
infinite-dimensional parameter, to be called a Banach parameter. Assume: (a)
There exists an efficient estimator of the Euclidean parameter. (b) When the
value of the Euclidean parameter is known, there exists an estimator of the
Banach parameter, which depends on this value and is efficient within this
restricted model. Substituting the efficient estimator of the Euclidean
parameter for the value of this parameter in the estimator of the Banach
parameter, one obtains an efficient estimator of the Banach parameter for the
full semiparametric model with the Euclidean parameter unknown. This hereditary
property of efficiency completes estimation in semiparametric models in which
the Euclidean parameter has been estimated efficiently. Typically, estimation
of both the Euclidean and the Banach parameter is necessary in order to
describe the random phenomenon under study to a sufficient extent. Since
efficient estimators are asymptotically linear, the above substitution method
is a particular case of substituting asymptotically linear estimators of a
Euclidean parameter into estimators that are asymptotically linear themselves
and that depend on this Euclidean parameter. This more general substitution
case is studied for its own sake as well, and a hereditary property for
asymptotic linearity is proved.Comment: Published at http://dx.doi.org/10.1214/009053604000000913 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Effective non-intercommutation of local cosmic strings at high collision speeds
We present evidence that Abrikosov-Nielsen-Olesen (ANO) strings pass through
each other for very high speeds of approach due to a double intercommutation.
In near-perpendicular collisions numerical simulations give threshold speeds
bounded above by for type I, and by for deep type
II strings. The second intercommutation occurs because at ultra high collision
speeds, the connecting segments formed by the first intercommutation are nearly
static and almost antiparallel, which gives them time to interact and
annihilate. A simple model explains the rough features of the threshold
velocity dependence with the incidence angle. For deep type II strings and
large incidence angles a second effect becomes dominant, the formation of a
loop that catches up with the interpolating segments. The loop is related to
the observed vortex - antivortex reemergence in two-dimensions. In this case
the critical value for double intercommutation can become much lower.Comment: 5 pages, 4 figures. data points added, plots for deep type II regime
showing lower critical velocities, some minor changes in tex
Kinematic Constraints on Formation of Bound States of Cosmic Strings - Field Theoretical Approach
Superstring theory predicts the potential formation of string networks with
bound states ending in junctions. Kinematic constraints for junction formation
have been derived within the Nambu-Goto thin string approximation. Here we test
these constraints numerically in the framework of the Abelian-Higgs model in
the Type-I regime and report on good agreement with the analytical predictions.
We also demonstrate that strings can effectively pass through each other when
they meet at speeds slightly above the critical velocity permitting bound state
formation. This is due to reconnection effects that are beyond the scope of the
Nambu-Goto approximation.Comment: 6 pages, 12 eps figures - matches the published versio
Constraints on massive sterile neutrino species from current and future cosmological data
Sterile massive neutrinos are a natural extension of the Standard Model of
elementary particles. The energy density of the extra sterile massive states
affects cosmological measurements in an analogous way to that of active
neutrino species. We perform here an analysis of current cosmological data and
derive bounds on the masses of the active and the sterile neutrino states as
well as on the number of sterile states. The so-called (3+2) models with three
sub-eV active massive neutrinos plus two sub-eV massive sterile species is well
within the 95% CL allowed regions when considering cosmological data only. If
the two extra sterile states have thermal abundances at decoupling, Big Bang
Nucleosynthesis bounds compromise the viability of (3+2) models. Forecasts from
future cosmological data on the active and sterile neutrino parameters are also
presented. Independent measurements of the neutrino mass from tritium beta
decay experiments and of the Hubble constant could shed light on sub-eV massive
sterile neutrino scenarios.Comment: 9 pages, 7 figures. Journal versio
Translation and validation of EORTC QLQ-C30 into Indonesian version for cancer patients in Indonesia.
The Indonesian version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-C30 can be used as a questionnaire to assess quality of life in Indonesian cancer patients with high-emetogenic treatments
Impact of chemotherapy-induced nausea and vomiting on quality of life in indonesian patients with gynecologic cancer.
Patients reported a negative impact on the QoL of delayed emesis after chemotherapy. Poor prophylaxis of patients' nausea and vomiting after chemotherapy interferes with patients' QoL. Medical and behavioral interventions may help to alleviate the negative consequences of chemotherapeutic treatment in patients with gynecologic cancers treated with suboptimal antiemetics
Exploiting Cross Correlations and Joint Analyses
In this report, we present a wide variety of ways in which information from
multiple probes of dark energy may be combined to obtain additional information
not accessible when they are considered separately. Fundamentally, because all
major probes are affected by the underlying distribution of matter in the
regions studied, there exist covariances between them that can provide
information on cosmology. Combining multiple probes allows for more accurate
(less contaminated by systematics) and more precise (since there is
cosmological information encoded in cross-correlation statistics) measurements
of dark energy. The potential of cross-correlation methods is only beginning to
be realized. By bringing in information from other wavelengths, the
capabilities of the existing probes of dark energy can be enhanced and
systematic effects can be mitigated further. We present a mixture of work in
progress and suggestions for future scientific efforts. Given the scope of
future dark energy experiments, the greatest gains may only be realized with
more coordination and cooperation between multiple project teams; we recommend
that this interchange should begin sooner, rather than later, to maximize
scientific gains.Comment: Report from the "Dark Energy and CMB" working group for the American
Physical Society's Division of Particles and Fields long-term planning
exercise ("Snowmass"
A direct probe of cosmological power spectra of the peculiar velocity field and the gravitational lensing magnification from photometric redshift surveys
The cosmological peculiar velocity field (deviations from the pure Hubble
flow) of matter carries significant information on dark energy, dark matter and
the underlying theory of gravity on large scales. Peculiar motions of galaxies
introduce systematic deviations between the observed galaxy redshifts z and the
corresponding cosmological redshifts z_cos. A novel method for estimating the
angular power spectrum of the peculiar velocity field based on observations of
galaxy redshifts and apparent magnitudes m (or equivalently fluxes) is
presented. This method exploits the fact that a mean relation between z_cos and
m of galaxies can be derived from all galaxies in a redshift-magnitude survey.
Given a galaxy magnitude, it is shown that the z_cos(m) relation yields its
cosmological redshift with a 1-sigma error of sigma_z~0.3 for a survey like
Euclid (~10^9 galaxies at z<~2), and can be used to constrain the angular power
spectrum of z-z_cos(m) with a high signal-to-noise ratio. At large angular
separations corresponding to l<~15, we obtain significant constraints on the
power spectrum of the peculiar velocity field. At 15<~l<~60, magnitude shifts
in the z_cos(m) relation caused by gravitational lensing magnification
dominate, allowing us to probe the line-of-sight integral of the gravitational
potential. Effects related to the environmental dependence in the luminosity
function can easily be computed and their contamination removed from the
estimated power spectra. The amplitude of the combined velocity and lensing
power spectra at z~1 can be measured with <~5% accuracy.Comment: 22 pages, 3 figures; added a discussion of systematic errors,
accepted for publication in JCA
Bestrijding van de wortelvlieg door middel van zaadcoating in peen, 2003 : toetsen van insecticiden op de wortelvlieglarve
In de teelt van peen (Daucus carota) is de wortelvlieg (Psila rosae (F.) ) een van de belangrijkste plagen. In Nederland kunnen drie generaties aanwezig zijn. Chloorfenvinfos als zaadbehandeling kan op basis van milieubelasting, hoewel op hectare basis slechts een fractie wordt gebruikt vergeleken met de granulaat toepassing, op termijn de toelating verliezen. Om deze redenen worden nieuwe middelen die minder milieu belastend zijn getoetst op hun effectiviteit om aantasting door de wortelvliegmade te voorkomen
- âŠ