Decoherence due to three-body loss and its effect on the state of a Bose-Einstein condensate

A Born-Markov master equation is used to investigate the decoherence of the state of a macroscopically occupied mode of a cold atom trap due to three-body loss. In the large number limit only coherent states remain pure for times longer than the decoherence time: the time it takes for just three atoms to be lost from the trap. For large numbers of atoms (N>10^4) the decoherence time is found to be much faster than the phase collapse time caused by intra-trap atomic collisions

Two Coupled Harmonic Oscillators on Non-commutative Plane

We investigate a system of two coupled harmonic oscillators on the non-commutative plane \RR^2_{\theta} by requiring that the spatial coordinates do not commute. We show that the system can be diagonalized by a suitable transformation, i.e. a rotation with a mixing angle \alpha. The obtained eigenstates as well as the eigenvalues depend on the non-commutativity parameter \theta. Focusing on the ground state wave function before the transformation, we calculate the density matrix \rho_0(\theta) and find that its traces {\rm Tr}(\rho_{0}(\theta)) and {\rm Tr}(\rho_0^2(\theta)) are not affected by the non-commutativity. Evaluating the Wigner function on \RR^2_{\theta} confirms this. The uncertainty relation is explicitly determined and found to depend on \theta. For small values of \theta, the relation is shifted by a \theta^2 term, which can be interpreted as a quantum correction. The calculated entropy does not change with respect to the normal case. We consider the limits \alpha=1 and \alpha={\pi\over 2}. In first case, by identifying \theta to the squared magnetic length, one can recover basic features of the Hall system.Comment: 15 pages, 1 figur

A virtual kitchen protocol to measure everyday memory functioning for meal preparation

In this study, we developed the Virtual Kitchen Protocol (VKP), a virtual reality-based measure of everyday memory functioning for meal preparation tasks. We investigated the construct validity of the VKP by comparing the performance of young adults (n = 41) and older adults without (n = 52) and with (n = 7) a neurocognitive diagnosis, as well as by examining correlations with standardized measures of verbal and visual memory. The results show that young adults had higher recall than older adults and that the VKP was sensitive to neurocognitive impairment among older adults. The VKP demonstrated moderate to high correlations with other memory tests. These results support the construct validity of the VKP and suggest that it holds promise as a virtual reality-based measure of memory for meal preparation tasks

Prenatal factors contribute to the emergence of kwoshiorkor or marasmus in severe undernutrition: evidence for the predictive adaptation model

Severe acute malnutrition in childhood manifests as oedematous (kwashiorkor, marasmic kwashiorkor) and non-oedematous (marasmus) syndromes with very different prognoses. Kwashiorkor differs from marasmus in the patterns of protein, amino acid and lipid metabolism when patients are acutely ill as well as after rehabilitation to ideal weight for height. Metabolic patterns among marasmic patients define them as metabolically thrifty, while kwashiorkor patients function as metabolically profligate. Such differences might underlie syndromic presentation and prognosis. However, no fundamental explanation exists for these differences in metabolism, nor clinical pictures, given similar exposures to undernutrition. We hypothesized that different developmental trajectories underlie these clinical-metabolic phenotypes: if so this would be strong evidence in support of predictive adaptation model of developmental plasticity

a Tū Ora/PREVIEW comparative study

3713851). Publisher Copyright: Copyright © 2023 Mathrani, Lu, Sequeira-Bisson, Silvestre, Hoggard, Barnett, Fogelholm, Raben, Poppitt and Taylor.Obesity-related metabolic diseases such as type 2 diabetes (T2D) are major global health issues, affecting hundreds of millions of people worldwide. The underlying factors are both diverse and complex, incorporating biological as well as cultural considerations. A role for ethnicity – a measure of self-perceived cultural affiliation which encompasses diet, lifestyle and genetic components – in susceptibility to metabolic diseases such as T2D is well established. For example, Asian populations may be disproportionally affected by the adverse ‘TOFI’ (Thin on the Outside, Fat on the Inside) profile, whereby outwardly lean individuals have increased susceptibility due to excess visceral and ectopic organ fat deposition. A potential link between the gut microbiota and metabolic disease has more recently come under consideration, yet our understanding of the interplay between ethnicity, the microbiota and T2D remains incomplete. We present here a 16S rRNA gene-based comparison of the fecal microbiota of European-ancestry and Chinese-ancestry cohorts with overweight and prediabetes, residing in New Zealand. The cohorts were matched for mean fasting plasma glucose (FPG: mean ± SD, European-ancestry: 6.1 ± 0.4; Chinese-ancestry: 6.0 ± 0.4 mmol/L), a consequence of which was a significantly higher mean body mass index in the European group (BMI: European-ancestry: 37.4 ± 6.8; Chinese-ancestry: 27.7 ± 4.0 kg/m2; p < 0.001). Our findings reveal significant microbiota differences between the two ethnicities, though we cannot determine the underpinning factors. In both cohorts Firmicutes was by far the dominant bacterial phylum (European-ancestry: 93.4 ± 5.5%; Chinese-ancestry: 79.6 ± 10.4% of 16S rRNA gene sequences), with Bacteroidetes and Actinobacteria the next most abundant. Among the more abundant (≥1% overall relative sequence abundance) genus-level taxa, four zero-radius operational taxonomic units (zOTUs) were significantly higher in the European-ancestry cohort, namely members of the Subdoligranulum, Blautia, Ruminoclostridium, and Dorea genera. Differential abundance analysis further identified a number of additional zOTUs to be disproportionately overrepresented across the two ethnicities, with the majority of taxa exhibiting a higher abundance in the Chinese-ancestry cohort. Our findings underscore a potential influence of ethnicity on gut microbiota composition in the context of individuals with overweight and prediabetes.publishersversionpublishe

Risk factors of visceral leishmaniasis in East Africa: a case-control study in Pokot territory of Kenya and Uganda

BACKGROUND: In East Africa, visceral leishmaniasis (VL) is endemic in parts of Sudan, Ethiopia, Somalia, Kenya and Uganda. It is caused by Leishmania donovani and transmitted by the sandfly vector Phlebotomus martini. In the Pokot focus, reaching from western Kenya into eastern Uganda, formulation of a prevention strategy has been hindered by the lack of knowledge on VL risk factors as well as by lack of support from health sector donors. The present study was conducted to establish the necessary evidence-base and to stimulate interest in supporting the control of this neglected tropical disease in Uganda and Kenya. METHODS: A case-control study was carried out from June to December 2006. Cases were recruited at Amudat hospital, Nakapiripirit district, Uganda, after clinical and parasitological confirmation of symptomatic VL infection. Controls were individuals that tested negative using a rK39 antigen-based dipstick, which were recruited at random from the same communities as the cases. Data were analysed using conditional logistic regression. RESULTS: Ninety-three cases and 226 controls were recruited into the study. Multivariate analysis identified low socio-economic status and treating livestock with insecticide as risk factors for VL. Sleeping near animals, owning a mosquito net and knowing about VL symptoms were associated with a reduced risk of VL. CONCLUSIONS: VL affects the poorest of the poor of the Pokot tribe. Distribution of insecticide-treated mosquito nets combined with dissemination of culturally appropriate behaviour-change education is likely to be an effective prevention strategy

Mammals in the Chornobyl Exclusion Zone's Red Forest: a motion-activated camera trap study

Since the accident at the Chornobyl Nuclear Power Plant in 1986, there have been few studies published on medium and large mammals inhabiting the area from which the human population was removed (now referred to as the Chornobyl Exclusion Zone, CEZ). The dataset presented in this paper describes a motion-activated camera trap study (n=21 cameras) conducted from September 2016 to September 2017 in the Red Forest located within the Chornobyl Exclusion Zone. The Red Forest, which is likely the most anthropogenically contaminated radioactive terrestrial ecosystem on earth, suffered a severe wildfire in July 2016. The motion-activated trap cameras were therefore in place as the Red Forest recovered from the wildfire. A total of 45 859 images were captured, and of these 19 391 contained identifiable species or organism types (e.g. insects). A total of 14 mammal species were positively identified together with 23 species of birds (though birds were not a focus of the study). Weighted absorbed radiation dose rates were estimated for mammals across the different camera trap locations; the number of species observed did not vary with estimated dose rate. We also observed no relationship between estimated weighted absorbed radiation dose rates and the number of triggering events for the four main species observed during the study (brown hare, Eurasian elk, red deer, roe deer). The data presented will be of value to those studying wildlife within the CEZ from the perspectives of the potential effects of radiation on wildlife and also rewilding in this large, abandoned area. They may also have value in any future studies investigating the impacts of the recent Russian military action in the CEZ. The data and supporting documentation are freely available from the Environmental Information Data Centre (EIDC) under the terms and conditions of a Creative Commons Attribution (CC BY) license: https://doi.org/10.5285/bf82cec2-5f8a-407c-bf74-f8689ca35e83 (Barnett et al., 2022a)

Probing Unstable Massive Neutrinos with Current Cosmic Microwave Background Observations

The pattern of anisotropies in the Cosmic Microwave Background depends upon the masses and lifetimes of the three neutrino species. A neutrino species of mass greater than 10 eV with lifetime between 10^{13} sec and 10^{17} sec leaves a very distinct signature (due to the integrated Sachs-Wolfe effect): the anisotropies at large angles are predicted to be comparable to those on degree scales. Present data exclude such a possibility and hence this region of parameter space. For $m_\nu \simeq 30$ eV, $\tau \simeq 10^{13}$ sec, we find an interesting possibility: the Integrated Sachs Wolfe peak produced by the decaying neutrino in low-$\Omega$ models mimics the acoustic peak expected in an $\Omega = 1$ model.Comment: 5 pages, 4 figure