685 research outputs found
Numerical computation and analysis of the Titchmarsh–Weyl mα(λ) function for some simple potentials
AbstractThis article is concerned with the Titchmarsh–Weyl mα(λ) function for the differential equation d2y/dx2+[λ−q(x)]y=0. The test potential q(x)=x2, for which the relevant mα(λ) functions are meromorphic, having simple poles at the points λ=4k+1 and λ=4k+3, is studied in detail. We are able to calculate the mα(λ) function both far from and near to these poles. The calculation is then extended to several other potentials, some of which do not have analytical solutions. Numerical data are given for the Titchmarsh–Weyl mα(λ) function for these potentials to illustrate the computational effectiveness of the method used
Experimental demonstration of coupled optical springs
Optical rigidity will play an important role in improving the sensitivity of future generations of gravitational wave (GW) interferometers, which employ high laser power in order to reach and exceed the standard quantum limit. Several experiments have demonstrated the combined effect of two optical springs on a single system for very low-weight mirror masses or membranes. In this paper we investigate the complex interactions between multiple optical springs and the surrounding apparatus in a system of comparable dynamics to a large-scale GW detector. Using three 100 g mirrors to form a coupled cavity system capable of sustaining two or more optical springs, we demonstrate a number of different regimes of opto-mechanical rigidity and measurement techniques. Our measurements reveal couplings between each optical spring and the control loops that can affect both the achievable increase in sensitivity and the stability of the system. Hence this work establishes a better understanding of the realisation of these techniques and paves the way to their application in future GW observatories, such as upgrades to Advanced LIGO
Perceived stress among dental students at the University of the Western Cape
Introduction: A high prevalence of stress among dental
students has been reported.
Aim: To determine perceived stress among dental students
at the University of the Western Cape.
Method: A self-administered questionnaire to students
(n=411) was used to collect data. Variables measured
included demographic characteristics of students and their
perceived stress in the dental environment using the Dental
Environment Stress (DES) survey and the Maslach Burnout
Inventory (MBI).
Results: The response rate was 78%. Respondents were
in the 18 to 21 age category; mostly female (n=207); multilingual,
with 63% having English as their home language.
Huge problems identified from the DES were lack of time
for relaxation, inadequate breaks during the day, fear of
failing a year or module, work load, inconsistency between
clinical supervisors and patients being late for appointments.
The MBI found high EE (28.91), low DP (7.13) and
high PA (30.06) scores. Fourth year students experienced
the highest degree of stress on the DES and MBI.
Conclusion: Stressors identified are consistent with
international dental literature. Levels of stress increased
over the academic years and peaked in the fourth year.
Stressors experienced may impact student academic and
future professional development, motivating a need for
intervention at Faculty level.DHE
On a representation of vector continued fractions.
Vector Pade approximants to power series with vector coefficients may be calculated using the three-term recurrence relations of vector continued fractionsif formulated in the framework of Clifford algebras. We show that the numerator and denominator polynomials of these fractions take particularly simple forms which require just a few degrees of freedom in their representation. The new description also allows the calculation of ”hybrid” approximants
Conformal symmetry and deflationary gas universe
We describe the ``deflationary'' evolution from an initial de Sitter phase to
a subsequent Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) period as a
specific non-equilibrium configuration of a self-interacting gas. The
transition dynamics corresponds to a conformal, timelike symmetry of an
``optical'' metric, characterized by a refraction index of the cosmic medium
which continously decreases from a very large initial value to unity in the
FLRW phase.Comment: 10 pages, to appear in "Exact Solutions and Scalar Fields in Gravity:
Recent Developments", ed. by A. Macias, J. Cervantes-Cota, and C.
L\"ammerzahl, Kluwer Academic Publishers 200
Fast Non-Adiabatic Two Qubit Gates for the Kane Quantum Computer
In this paper we apply the canonical decomposition of two qubit unitaries to
find pulse schemes to control the proposed Kane quantum computer. We explicitly
find pulse sequences for the CNOT, swap, square root of swap and controlled Z
rotations. We analyze the speed and fidelity of these gates, both of which
compare favorably to existing schemes. The pulse sequences presented in this
paper are theoretically faster, higher fidelity, and simpler than existing
schemes. Any two qubit gate may be easily found and implemented using similar
pulse sequences. Numerical simulation is used to verify the accuracy of each
pulse scheme
Perceived stressors of oral hygiene students in the dental environment
University students are exposed to a multitude of stressors that may impact on their performance. The nature of health sciences education
generally involves early engagement with patients and communities, which may add to the stressors inherent to university life. There is sparse information
on stressors in the oral hygiene educational environment.
Objective. To determine perceived stressors and the level of burnout among oral hygiene students at the University of the Western Cape, Cape Town,
South Africa.
A descriptive, cross-sectional study design was used. The study sample included all students in the Bachelor of Oral Health (BOH) degree during 2012
(N=89). A self-administered questionnaire was used to gather data. Three parameters were measured, i.e. (i) demographic characteristics; (ii) perceived sources
of stress, using a modified Dental Environment Stress (DES) questionnaire; and (iii) burnout, using the Maslach Burnout Inventory (MBI).
Respondents were mostly female (74%) and primarily in the 18 - 25-year age group (92%). First- and 2nd-year students identified fear of failing
and study load as major stressors. Stressors related to a lack of basic needs were identified as major stressors by 25% of 1st-year students. Third-year
students identified clinical quotas, supervision and patients being late as major stressors. MBI scores indicated that students were not at risk for burnout;
however, most students (66.2%) scored high on emotional exhaustion (EE).
Oral hygiene students identified stressors in their learning environment. There was a progressive increase in EE across academic years.
The results suggest that interventions should be tailored for specific academic year groups
Delivering a positive outcome for STEM students– how TEF will that be?
As universities embrace widening participation, we are starting to observe sector-wide awarding gaps, and with student continuation within Engineering & Technology as one of the lowest in Higher Education (HE), it would appear that our current curricular is not always effective for the attainment of a diverse student body. This paper highlights the external driving forces related to the widening participation within HE and how this is influencing STEM education. It describes the current practice that has positively influenced diversity awareness and how HE can use the student voice more effectively to drive forward both institutional change and programme curricula design to ensure positive outcomes for all students
Effect of selective removal of badgers (Meles meles) on ranging behaviour during a ‘Test and Vaccinate or Remove’ intervention in Northern Ireland
Publication history: Accepted - 23 April 2021; Published online - 7 May 2021The role of the Eurasian badger (Meles meles) as a wildlife host has complicated the management of bovine tuberculosis (bTB) in cattle. Badger ranging behaviour has previously been found to be altered by culling of badgers and has been suggested to increase the transmission
of bTB either among badgers or between badgers and cattle. In 2014, a five-year bTB intervention research project in a 100 km2 area in Northern Ireland was initiated involving selective removal of dual path platform (DPP) VetTB (immunoassay) test positive badgers and vaccination followed by release of DPP test negative badgers (‘Test and Vaccinate or
Remove’). Home range sizes, based on position data obtained from global positioning system collared badgers, were compared between the first year of the project, where no DPP test positive badgers were removed, and follow-up years 2–4 when DPP test positive badgers were
removed. A total of 105 individual badgers were followed over 21 200 collar tracking nights. Using multivariable analyses, neither annual nor monthly home ranges differed significantly in size between years, suggesting they were not significantly altered by the bTB intervention
that was applied in the study area.This research was funded by the Department of Agriculture, Environment and Rural Affairs for Northern Ireland
Electron Scattering From High-Momentum Neutrons in Deuterium
We report results from an experiment measuring the semi-inclusive reaction
where the proton is moving at a large angle relative to the
momentum transfer. If we assume that the proton was a spectator to the reaction
taking place on the neutron in deuterium, the initial state of that neutron can
be inferred. This method, known as spectator tagging, can be used to study
electron scattering from high-momentum (off-shell) neutrons in deuterium. The
data were taken with a 5.765 GeV electron beam on a deuterium target in
Jefferson Laboratory's Hall B, using the CLAS detector. A reduced cross section
was extracted for different values of final-state missing mass ,
backward proton momentum and momentum transfer . The data
are compared to a simple PWIA spectator model. A strong enhancement in the data
observed at transverse kinematics is not reproduced by the PWIA model. This
enhancement can likely be associated with the contribution of final state
interactions (FSI) that were not incorporated into the model. A ``bound neutron
structure function'' was extracted as a function of and
the scaling variable at extreme backward kinematics, where effects of
FSI appear to be smaller. For MeV/c, where the neutron is far
off-shell, the model overestimates the value of in the region of
between 0.25 and 0.6. A modification of the bound neutron structure
function is one of possible effects that can cause the observed deviation.Comment: 33 pages RevTeX, 9 figures, to be submitted to Phys. Rev. C. Fixed 1
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