6 research outputs found
The relationship between species detection probability and local extinction probability.
In community-level ecological studies, generally not all species present in sampled areas are detected. Many authors have proposed the use of
estimation methods that allow detection probabilities that are <1 and that are heterogeneous among species. These methods can also be used to
estimate community-dynamic parameters such as species local extinction probability and turnover rates (Nichols et al. Ecol Appl 8:1213–1225;
Conserv Biol 12:1390–1398). Here, we present an ad hoc approach to estimating community-level vital rates in the presence of joint
heterogeneity of detection probabilities and vital rates. The method consists of partitioning the number of species into two groups using the
detection frequencies and then estimating vital rates (e.g., local extinction probabilities) for each group. Estimators from each group are combined
in a weighted estimator of vital rates that accounts for the effect of heterogeneity. Using data from the North American Breeding Bird Survey, we
computed such estimates and tested the hypothesis that detection probabilities and local extinction probabilities were negatively related. Our
analyses support the hypothesis that species detection probability covaries negatively with local probability of extinction and turnover rates. A
simulation study was conducted to assess the performance of vital parameter estimators as well as other estimators relevant to questions about
heterogeneity, such as coefficient of variation of detection probabilities and proportion of species in each group. Both the weighted estimator
suggested in this paper and the original unweighted estimator for local extinction probability performed fairly well and provided no basis for
preferring one to the other
Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation
The current status of electric dipole moments of diamagnetic atoms which
involves the synergy between atomic experiments and three different theoretical
areas -- particle, nuclear and atomic is reviewed. Various models of particle
physics that predict CP violation, which is necessary for the existence of such
electric dipole moments, are presented. These include the standard model of
particle physics and various extensions of it. Effective hadron level combined
charge conjugation (C) and parity (P) symmetry violating interactions are
derived taking into consideration different ways in which a nucleon interacts
with other nucleons as well as with electrons. Nuclear structure calculations
of the CP-odd nuclear Schiff moment are discussed using the shell model and
other theoretical approaches. Results of the calculations of atomic electric
dipole moments due to the interaction of the nuclear Schiff moment with the
electrons and the P and time-reversal (T) symmetry violating
tensor-pseudotensor electron-nucleus are elucidated using different
relativistic many-body theories. The principles of the measurement of the
electric dipole moments of diamagnetic atoms are outlined. Upper limits for the
nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained
combining the results of atomic experiments and relativistic many-body
theories. The coefficients for the different sources of CP violation have been
estimated at the elementary particle level for all the diamagnetic atoms of
current experimental interest and their implications for physics beyond the
standard model is discussed. Possible improvements of the current results of
the measurements as well as quantum chromodynamics, nuclear and atomic
calculations are suggested.Comment: 46 pages, 19 tables and 16 figures. A review article accepted for
EPJ