683 research outputs found
BCS-BEC crossover in a strongly correlated Fermi gas
We study the BCS-BEC crossover in the strongly correlated regime of an
ultra-cold rotating two component Fermi gas. Strong correlations are shown to
generate an additional long-range interaction which results in a modified
crossover region compared to the non-rotating situation. The two-particle
correlation function reveals a smooth crossover between the s-wave paired
fermionic fractional quantum Hall state and the bosonic Laughlin state.Comment: 4 pages, 3 figure
Sustainable Soesterkwartier
The municipality of Amersfoort wants to construct an endurable and sustainable eco-town in the Soesterkwartier neighbourhood, by taking future climate change into account. The impact of climate change at the location of the proposed eco-town was studied by a literature review
Recruitment and retention of IT staff within a leading South African bank
The Information Technology (IT) industry is currently faced with a shrinking pool of skilled IT employees as a result of the increasing demand for these employees. This increasing demand has put organisations under pressure to start devising retention strategies in order to retain the targeted employees. This paper is based on the study that was done in the IT department of one of the leading banks in South Africa. The study was conducted in order to understand the leadership's view on employee attraction and retention, and how these can be used as tools for reducing skills shortages in the IT department of the understudied bank. Findings of this study, which followed a qualitative methodology, indicated that high employee turnover is the main contributor of the skills shortages within this department. The non-existence of a proper retention strategy is making it difficult for the leadership team to identify the type of skills that are critical to the organisation and to retain such skills
Death and injury on duty- a study of South African police officers
Objectives. Sections of contemporary South African society are characterised by high levels of crime and interpersonal conflict. The South African Police Service (SAPS) is in the front line, with many deaths and injuries occuring among serving officers in recent years. The circumstances and nature of the injuries sustained by these officers have received little attention in the medical literature.Design. A retrospective review of all injured SAPS members was undertaken at a single level one trauma centre in Johannesburg between June 1993 and June 2002. The following factors were recorded: demographics, mechanism and anatomical site of injury, mode of transportation to hospital, whether personal protection had been used, mortality, and return to work.Results. One hundred and thirty-four SAPS personnel were admitted over a 9-year period. The majority (95%) were male and the median age was 31 years. One hundred and thirty two were on duty and two were in transit to a place of duty when injured. Ninety-two (69%) were injured by gunshot, (including 3 attempted suicides and 9 injuries due to negligent discharge), 2 members were stabbed, 31 were involved in motor vehicle accidents, 2 in motorbike accidents, 1 member was struck by a car while directing traffic, 3 officers were injured by falls from a height, 2 members were injured in helicopter crashes, and 1 member required treatment for gas inhalation. Documentation on whether some form of personal protection was worn at the time of injury was only available for 43 of the 92 cases of gunshot wounds (47%); of these, only 15 (35%) were wearing a bulletproof vest. Use or non-use of a seat belt was documented by hospital staff for only 6 of the 31 officers (19%) injured in motor vehicle accidents. None of the 6 officers had been restrained by a seatbelt. Nineteen SAPS personnel (14%) died of their injuries, but the majority of surviving members returned to duty.Conclusion. There is an unacceptably high level of violence in South African society today and SAPS members regularlyhave to deal with dangerous or violent situations. There is a clear need to introduce a reporting system within the SAPS to record the use of personal protection by officers. Education needs to target SAPS members in order to enhance their use of personal protection. There is a further need to design and implement personal protection that will be universally acceptable by SAPS members
Feshbach resonances in 3He*-4He* mixtures
We discuss the stability of homonuclear and heteronuclear mixtures of 3He and
4He atoms in the metastable 2^3S_1 state (He*) and predict positions and widths
of Feshbach resonances by using the Asymptotic Bound-state Model (ABM). All
calculations are performed without fit parameters, using \emph{ab-initio}
calculations of molecular potentials. One promising very broad Feshbach
resonance (\Delta B=72.9^{+18.3}_{-19.3} mT) is found that allows for tuning of
the inter-isotope scattering length.Comment: 12 pages, 7 figure
Habitat use by demersal nekton on the continental shelf in the Benguela ecosystem, southern Africa
Videotapes collected by the research submersible Jago in the Benguela ecosystem during spring 1997 were analyzed to determine demersal nekton assemblage composition, fish behavior, and microscale habitat association, and habitat selection. Demersal fish assemblage diversity was generally low, and their composition was a function of substratum type. Individual species showed an often marked association with either rocky or soft substrata (or both), and a strong or weak selection for the associated biota. Soles and dragonets actively selected areas of bioactive soft substrata, to which they are behaviorally and morphologically adapted. False jacopever were associated with crevices in areas of high-relief rocky substrata. Kingklip are piscivorous and were largely confined to holes at the base of rocks and favored areas without a conspicuous epifauna. Juvenile hake and gobies avoided extremely rocky areas and were largely indifferent to the presence of benthic invertebrates—behavior that is consistent with their planktonic diets. These results represent the first direct observations of demersal nekton in the region and are important because they allow better interpretations of the results of trawl studies
Asymptotic Bound-state Model for Feshbach Resonances
We present an Asymptotic Bound-state Model which can be used to accurately
describe all Feshbach resonance positions and widths in a two-body system. With
this model we determine the coupled bound states of a particular two-body
system. The model is based on analytic properties of the two-body Hamiltonian,
and on asymptotic properties of uncoupled bound states in the interaction
potentials. In its most simple version, the only necessary parameters are the
least bound state energies and actual potentials are not used. The complexity
of the model can be stepwise increased by introducing threshold effects,
multiple vibrational levels and additional potential parameters. The model is
extensively tested on the 6Li-40K system and additional calculations on the
40K-87Rb system are presented.Comment: 13 pages, 8 figure
Nestling White-backed Vulture (Gyps africanus) eaten by a Verreaux’s Eagle (Aquila verreauxii) at a nest occupied for a record 21 years.
An adult Verreaux’s Eagle (Aquila verreauxii) was observed eating a White-backed Vulture (Gyps africanus) nestling at a nest at Sango in the Savé Valley Conservancy, south-eastern Zimbabwe on 13 October 2017. This nest has been regularly occupied for 21 successive breeding seasons. To our knowledge, this observation represents a previously unrecorded species in the diet of Verreaux’s Eagle, and it is also apparently the longest known continually-occupied White-backed Vulture nest
Broad Feshbach resonance in the 6Li-40K mixture
We study the widths of interspecies Feshbach resonances in a mixture of the
fermionic quantum gases 6Li and 40K. We develop a model to calculate the width
and position of all available Feshbach resonances for a system. Using the model
we select the optimal resonance to study the 6Li/40K mixture. Experimentally,
we obtain the asymmetric Fano lineshape of the interspecies elastic cross
section by measuring the distillation rate of 6Li atoms from a potassium-rich
6Li/40K mixture as a function of magnetic field. This provides us with the
first experimental determination of the width of a resonance in this mixture,
Delta B=1.5(5) G. Our results offer good perspectives for the observation of
universal crossover physics using this mass-imbalanced fermionic mixture.Comment: 4 pages, 2 figure
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