13,829 research outputs found
Semiclassical initial value calculations of collinear helium atom
Semiclassical calculations using the Herman-Kluk initial value treatment are
performed to determine energy eigenvalues of bound and resonance states of the
collinear helium atom. Both the configuration (where the classical motion
is fully chaotic) and the configuration (where the classical dynamics is
nearly integrable) are treated. The classical motion is regularized to remove
singularities that occur when the electrons collide with the nucleus. Very good
agreement is obtained with quantum energies for bound and resonance states
calculated by the complex rotation method.Comment: 24 pages, 3 figures. Submitted to J. Phys.
Prevalence of sulfonamide resistance genes in bacterial isolates from manured agricultural soils and pig slurry in the United Kingdom
Prevalence of three sulfonamide resistance genes, sul1, sul2 and sul3 and sulfachloropyridazine (SCP) resistance was determined in bacteria isolated from UK manured agricultural clay soils and slurry samples, over a two year period. Slurry from tylosin-fed pigs amended with SCP and oxytetracycline (OTC) was used for manuring. Sul gene positive isolates were further screened for the presence of class 1 and 2 integrons. Phenotypic resistance to SCP was significantly higher in pig slurry and post application soil than in pre-application soil. Of 5isolates, 23 % carried sul1, 18 % sul2 and 9 % sul3 only. Two percent of isolates contained all three sul genes. Class 1 and class 2 integrons were identified in 5 % and 11.7 % of sul positive isolates. In previous reports, sul1 was linked to class 1 integrons, but in this study only 8 % of sul1 positive isolates carried the intI1 gene. Sulfonamide resistant pathogens were identified in slurry amended soil and soil leachate, including Shigella flexneri, Aerococcus spp. and Acinetobacter baumanni, suggesting a potential environmental reservoir. Sulfonamide resistance in Psychrobacter, Enterococcus and Bacillus spp. is reported for the first time, and this study also provides the first description of the genotype sul1, sul2 and sul3 outside the Enterobacteriacae, and in the soil environment
Integron prevalence and diversity in manured soil
Integron abundance and diversity were studied in soil amended with pig slurry. Real-time PCR illustrated a significant increase in class 1 integron prevalence post slurry-application with increased prevalence still evident at 10 months post-application. Culture dependent data revealed 10 genera, including putative human pathogens, carrying class 1 and 2 integrons
'Heaven starts at your parents' feet' : adolescent bowing to parents and associated spiritual attitudes
In a quantitative survey of religious attitudes and practices in a multi-religious sample of
369 school pupils aged between 13 and 15 in London, the practice of bowing to parents was
found widespread in 22% of adolescents spanning several religious affiliations and
ethnicities – especially Buddhists, Hindus and those of Indian, African and ‘Other Asian’
ethnicity. Whether an adolescent bowed correlated significantly with spiritual attitudes such
as wanting to abstain from alcohol, hearing religious stories, being inspired by religious
festivals and liking the idea of seeing God in everything. Findings suggest bowing to
parents can have religious significance on all three levels of Jackson’s Interpretive
Approach and therefore cannot be regarded as a ‘cultural accretion’ of religion. Study of
bowing to parents could form a unifying exercise in shared values for study of religion in
the plural classroom and facilitate community cohesion in certain religious membership
groups
Attitudes and Values of Adolescent Europeans towards Europeanisation
Based on original empirical data collected from adolescents in Europe (N=9003) this paper focuses on the lifeworlds of young people. It analyses negative and positive patterns of attitude and combines them with further concepts: first, personal life perspectives, various key values and political attitudes, second, religious attitudes towards church(es), religions, world views and religious education. Technically, the attitude towards Europe acts as the dependent variable whereas the remaining concepts are used as independent variables. The empirical results show Turkish and Polish adolescents are more critical of Europe than adolescents living in “old” Europe. Furthermore, the data show that those who have negative expectations about their personal futures and follow a more traditional religious world view are likely also to be Eurosceptical
Dietary dairy product intake and incident type 2 diabetes: a prospective study using dietary data from a 7-day food diary
The consumption of specific dairy types may be beneficial for the prevention of diabetes.
Abstract: The aim of this study was to investigate the association between total and types of dairy product intake and risk of developing incident type 2 diabetes, using a food diary.
Methods: A nested case-cohort within the EPIC-Norfolk Study was examined, including a random subcohort
(n=4,000) and cases of incident diabetes (n=892, including 143 cases in the subcohort) followed-up for 11 years. Diet was assessed using a prospective 7-day food diary. Total dairy intake (g/day) was estimated and categorised into high-fat
(≥3.9%) and low-fat (<3.9% fat) dairy, and by subtype into yoghurt, cheese and milk. Combined fermented dairy product
intake (yoghurt, cheese, sour cream) was estimated and categorised into high- and low-fat. Prentice-weighted Cox
regression HRs were calculated.
Results: Total dairy, high-fat dairy, milk, cheese and high-fat fermented dairy product intakes were not associated with the
development of incident diabetes. Low-fat dairy intake was inversely associated with diabetes in age- and sex-adjusted
analyses (tertile [T] 3 vs T1, HR 0.81 [95% CI 0.66, 0.98]), but further adjustment for anthropometric, dietary and diabetes
risk factors attenuated this association. In addition, an inverse association was found between diabetes and low-fat
fermented dairy product intake (T3 vs T1, HR 0.76 [95% CI 0.60, 0.99]; ptrend=0.049) and specifically with yoghurt intake
(HR 0.72 [95% CI 0.55, 0.95]; ptrend=0.017) in multivariable adjusted analyses.
Conclusions/interpretation: Greater low-fat fermented dairy product intake, largely driven by yoghurt intake, was associated with a decreased risk of type 2 diabetes development in prospective analyses. These findings suggest that the consumption of specific dairy types may be beneficial for the prevention of diabetes, highlighting the importance of food
group subtypes for public health messages
Quantum state transfer in spin chains with q-deformed interaction terms
We study the time evolution of a single spin excitation state in certain
linear spin chains, as a model for quantum communication. Some years ago it was
discovered that when the spin chain data (the nearest neighbour interaction
strengths and the magnetic field strengths) are related to the Jacobi matrix
entries of Krawtchouk polynomials or dual Hahn polynomials, so-called perfect
state transfer takes place. The extension of these ideas to other types of
discrete orthogonal polynomials did not lead to new models with perfect state
transfer, but did allow more insight in the general computation of the
correlation function. In the present paper, we extend the study to discrete
orthogonal polynomials of q-hypergeometric type. A remarkable result is a new
analytic model where perfect state transfer is achieved: this is when the spin
chain data are related to the Jacobi matrix of q-Krawtchouk polynomials. The
other cases studied here (affine q-Krawtchouk polynomials, quantum q-Krawtchouk
polynomials, dual q-Krawtchouk polynomials, q-Hahn polynomials, dual q-Hahn
polynomials and q-Racah polynomials) do not give rise to models with perfect
state transfer. However, the computation of the correlation function itself is
quite interesting, leading to advanced q-series manipulations
Nonstationary dynamics of the Alessandro-Beatrice-Bertotti-Montorsi model
We obtain an exact solution for the motion of a particle driven by a spring
in a Brownian random-force landscape, the Alessandro-Beatrice-Bertotti-Montorsi
(ABBM) model. Many experiments on quasi-static driving of elastic interfaces
(Barkhausen noise in magnets, earthquake statistics, shear dynamics of granular
matter) exhibit the same universal behavior as this model. It also appears as a
limit in the field theory of elastic manifolds. Here we discuss predictions of
the ABBM model for monotonous, but otherwise arbitrary, time-dependent driving.
Our main result is an explicit formula for the generating functional of
particle velocities and positions. We apply this to derive the
particle-velocity distribution following a quench in the driving velocity. We
also obtain the joint avalanche size and duration distribution and the mean
avalanche shape following a jump in the position of the confining spring. Such
non-stationary driving is easy to realize in experiments, and provides a way to
test the ABBM model beyond the stationary, quasi-static regime. We study
extensions to two elastically coupled layers, and to an elastic interface of
internal dimension d, in the Brownian force landscape. The effective action of
the field theory is equal to the action, up to 1-loop corrections obtained
exactly from a functional determinant. This provides a connection to
renormalization-group methods.Comment: 18 pages, 3 figure
Improved detection of small atom numbers through image processing
We demonstrate improved detection of small trapped atomic ensembles through
advanced post-processing and optimal analysis of absorption images. A fringe
removal algorithm reduces imaging noise to the fundamental photon-shot-noise
level and proves beneficial even in the absence of fringes. A
maximum-likelihood estimator is then derived for optimal atom-number estimation
and is applied to real experimental data to measure the population differences
and intrinsic atom shot-noise between spatially separated ensembles each
comprising between 10 and 2000 atoms. The combined techniques improve our
signal-to-noise by a factor of 3, to a minimum resolvable population difference
of 17 atoms, close to our ultimate detection limit.Comment: 4 pages, 3 figure
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