8,977 research outputs found
Efficient calculation of chiral three-nucleon forces up to N3LO for ab initio studies
We present a novel framework to decompose three-nucleon forces in a momentum
space partial-wave basis. The new approach is computationally much more
efficient than previous methods and opens the way to ab initio studies of
few-nucleon scattering processes, nuclei and nuclear matter based on
higher-order chiral 3N forces. We use the new framework to calculate matrix
elements of chiral three-nucleon forces at N2LO and N3LO in large basis spaces
and carry out benchmark calculations for neutron matter and symmetric nuclear
matter. We also study the size of the individual three-nucleon force
contributions for H. For nonlocal regulators, we find that the sub-leading
terms, which have been neglected in most calculations so far, provide important
contributions. All matrix elements are calculated and stored in a user-friendly
way, such that values of low-energy constants as well as the form of regulator
functions can be chosen freely.Comment: 10 pages, 4 figure
Field methods for rodent studies in Asia and the Indo-Pacific
Farm Management,
Organizational Chart Inference
Nowadays, to facilitate the communication and cooperation among employees, a
new family of online social networks has been adopted in many companies, which
are called the "enterprise social networks" (ESNs). ESNs can provide employees
with various professional services to help them deal with daily work issues.
Meanwhile, employees in companies are usually organized into different
hierarchies according to the relative ranks of their positions. The company
internal management structure can be outlined with the organizational chart
visually, which is normally confidential to the public out of the privacy and
security concerns. In this paper, we want to study the IOC (Inference of
Organizational Chart) problem to identify company internal organizational chart
based on the heterogeneous online ESN launched in it. IOC is very challenging
to address as, to guarantee smooth operations, the internal organizational
charts of companies need to meet certain structural requirements (about its
depth and width). To solve the IOC problem, a novel unsupervised method Create
(ChArT REcovEr) is proposed in this paper, which consists of 3 steps: (1)
social stratification of ESN users into different social classes, (2)
supervision link inference from managers to subordinates, and (3) consecutive
social classes matching to prune the redundant supervision links. Extensive
experiments conducted on real-world online ESN dataset demonstrate that Create
can perform very well in addressing the IOC problem.Comment: 10 pages, 9 figures, 1 table. The paper is accepted by KDD 201
Optically probing the fine structure of a single Mn atom in an InAs quantum dot
We report on the optical spectroscopy of a single InAs/GaAs quantum dot (QD)
doped with a single Mn atom in a longitudinal magnetic field of a few Tesla.
Our findings show that the Mn impurity is a neutral acceptor state A^0 whose
effective spin J=1 is significantly perturbed by the QD potential and its
associated strain field. The spin interaction with photo-carriers injected in
the quantum dot is shown to be ferromagnetic for holes, with an effective
coupling constant of a few hundreds of micro-eV, but vanishingly small for
electrons.Comment: 5 pages, 3 figure
Study of the general mechanism of stress corrosion of aluminum alloys and development of techniques for its detection Quarterly report, 1 Dec. 1967 - 29 Feb. 1968
Stress corrosion of aluminum alloys and techniques for its detectio
Experimental Predictions of The Functional Response of A Freshwater Fish
The functional response is the relationship between the feeding rate of an animal and its food density. It is reliant on two basic parameters; the volume searched for prey per unit time (searching rate) and the time taken to consume each prey item (handling time). As fish functional responses can be difficult to determine directly, it may be more feasible to measure their underlying behavioural parameters in controlled conditions and use these to predict the functional response. Here, we tested how accurately a Type II functional response model predicted the observed functional response of roach Rutilus rutilus, a visually foraging fish, and compared it with Type I functional response. Foraging experiments were performed by exposing fish in tank aquaria to a range of food densities, with their response captured using a two-camera videography system. This system was validated and was able to accurately measure fish behaviour in the aquaria, and enabled estimates of fish reaction distance, swimming speed (from which searching rate was calculated) and handling time to be measured. The parameterised Type II functional response model accurately predicted the observed functional response and was superior to the Type I model. These outputs suggest it will be possible to accurately measure behavioural parameters in other animal species and use these to predict the functional response in situations where it cannot be observed directly
Study of the general mechanism of stress corrosion of aluminum alloys and development of techniques for its detection Annual summary report, 2 Jun. 1967 - 1 Jun. 1968
Stress corrosion cracking of high strength aluminum alloys investigated by electrochemical, mechanical, and electron microscopic technique
Effects of culling on badger abundance : implications for tuberculosis control
Culling is often considered as a tool for controlling wildlife diseases that can also infect people or livestock. Culling European badgers Meles meles can cause both positive and negative effects on the incidence of bovine tuberculosis (TB) in cattle. One factor likely to influence the outcome of different badger culling strategies for cattle TB is the reduction in badger population density achieved. However, this reduction is difficult to measure because badgers, being nocturnal and fossorial, are difficult to count. Here, we use indices of badger abundance to measure the population impacts of two culling strategies tested in Britain. The densities of badger setts and latrines recorded before culling were correlated with the densities of badgers captured on initial culls, suggesting that both were indices of actual badger abundance. Widespread 'proactive' culling was associated with a 73% reduction in the density of badger latrines, a 69% reduction in the density of active burrows and a 73% reduction in the density of road killed badgers. This population reduction was achieved by a coordinated effort entailing widespread and repeated trapping over several years. However, this strategy caused only modest reductions in cattle TB incidence in culled areas and elevated incidence in neighbouring unculled areas. Localized 'reactive' culling caused a 26% reduction in latrine density, a 32% reduction in active burrow density and a 10% reduction in the density of road killed badgers, but apparently increased the incidence of cattle TB. These results indicate that the relationship between badger population reduction and TB transmission to cattle is strongly non linear, probably because culling prompts changes in badger behaviour that influence transmission rates. These findings raise serious questions about the capacity of badger culling to contribute to the control of cattle TB in Britain
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