339 research outputs found

    Quantum Markov Chain Monte Carlo with Digital Dissipative Dynamics on Quantum Computers

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    Modeling the dynamics of a quantum system connected to the environment is critical for advancing our understanding of complex quantum processes, as most quantum processes in nature are affected by an environment. Modeling a macroscopic environment on a quantum simulator may be achieved by coupling independent ancilla qubits that facilitate energy exchange in an appropriate manner with the system and mimic an environment. This approach requires a large, and possibly exponential number of ancillary degrees of freedom which is impractical. In contrast, we develop a digital quantum algorithm that simulates interaction with an environment using a small number of ancilla qubits. By combining periodic modulation of the ancilla energies, or spectral combing, with periodic reset operations, we are able to mimic interaction with a large environment and generate thermal states of interacting many-body systems. We evaluate the algorithm by simulating preparation of thermal states of the transverse Ising model. Our algorithm can also be viewed as a quantum Markov chain Monte Carlo (QMCMC) process that allows sampling of the Gibbs distribution of a multivariate model. To demonstrate this we evaluate the accuracy of sampling Gibbs distributions of simple probabilistic graphical models using the algorithm

    Deep Near-IR Surface Photometry of 57 Galaxies in the Local Sphere of Influence

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    We present H-band surface photometry of 57 galaxies drawn from the Local Sphere of Influence (LSI) with distances of less than 10 Mpc from the Milky Way. The images with a typical surface brightness limit 4 mag fainter than 2MASS (24.5 mag arcsec^-2 < sb_lim < 26 mag arcsec ^-2) have been obtained with IRIS2 on the 3.9 m Anglo-Australian Telescope. A total of 22 galaxies that remained previously undetected in the near-IR and potentially could have been genuinely young galaxies were found to have an old stellar population with a star density 1-2 magnitudes below the 2MASS detection threshold. The cleaned near-IR images reveal the morphology and extent of many of the galaxies for the first time. For all program galaxies, we derive radial luminosity profiles, ellipticities, and position angles, together with global parameters such as total magnitude, mean effective surface brightness and half-light radius. Our results show that 2MASS underestimates the total magnitude of galaxies with _eff between 18-21 mag arcsec^-2 by up to 2.5 mag. The Sersic parameters best describing the observed surface brightness profiles are also presented. Adopting accurate galaxy distances and a H-band mass-to-light ratio of Upsilon_H=1.0 +/- 0.4, the LSI galaxies are found to cover a stellar mass range of 5.6 < log_10 (M_stars) < 11.1. The results are discussed along with previously obtained optical data. Our sample of low luminosity galaxies is found to follow closely the optical-infrared B versus H luminosity relation defined by brighter galaxies with a slope of 1.14 +/- 0.02 and scatter of 0.3 magnitudes. Finally we analyse the luminosity - surface brightness relation to determine an empirical mass-to-light ratio of Upsilon_H=0.78 +/- 0.08 for late-type galaxies in the H-band.Comment: Accepted by AJ. High resolution version available at http://www.mso.anu.edu.au/~emma/KirbyHband.pd

    Psychological factors associated with changes in physical activity in Dutch people with type 2 diabetes under societal lockdown:A cross-sectional study

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    AIMS: To investigate changes in physical activity (PA) and psychological factors during societal lockdown in people with type 2 diabetes. METHODS: A cross‐sectional study among Dutch adults with type 2 diabetes. Data were collected using online questionnaires. A multivariate multinomial logistic regression was performed with change in PA during societal lockdown as outcome and perceived change in stress, anxiety, perceived risk for COVID‐19 infection, emotional well‐being and former PA status as determinants. RESULTS: Five hundred and sixty seven respondents filled out the questionnaire, 536 were included in the final analysis: mean age of 65.9 ± 7.9 years; mean diabetes duration 13.3 ± 8 years; 54% men; 47% reported no change in PA, 27% became less active and 26% became more active during societal lockdown. Participants who were more likely to become less active were participants who experienced more stress (OR: 2.27; 95% CI 1.25–4.13) or less stress (OR: 2.20; 95% CI 1.03–4.71). Participants who were more likely to become more active were participants who experienced more stress (OR: 2.31; 95% CI 1.25, 4.26). Participants with higher emotional well‐being (OR: 0.98; 95% CI 0.97, 0.99) were less likely to become less active than to report no change in PA. CONCLUSIONS: Changes in PA in people with type 2 diabetes during societal lockdown are associated with changes in psychological factors such as perceived stress and emotional well‐being. People with diabetes and their caregivers should be aware of these possible changes

    Magnesium intake and vascular structure and function:the Hoorn Study

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    PURPOSE: Circulating and dietary magnesium have been shown to be inversely associated with the prevalence of cardiovascular disease (CVD) and mortality in both high and low-risk populations. We aimed to examine the association between dietary magnesium intake and several measures of vascular structure and function in a prospective cohort. METHODS: We included 789 participants who participated in the vascular screening sub-cohort of the Hoorn Study, a population-based, prospective cohort study. Baseline dietary magnesium intake was estimated with a validated food frequency questionnaire and categorised in energy-adjusted magnesium intake tertiles. Several measurements of vascular structure and function were performed at baseline and most measurements were repeated after 8 years of follow-up (n = 432). Multivariable linear and logistic regression was performed to study the cross-sectional and longitudinal associations of magnesium intake and intima-media thickness (IMT), augmentation index (Aix), pulse wave velocity (PWV), flow-mediated dilatation (FMD), and peripheral arterial disease (PAD). RESULTS: Mean absolute magnesium intake was 328 ± 83 mg/day and prior CVD and DM2 was present in 55 and 41% of the participants, respectively. Multivariable regression analyses did not demonstrate associations between magnesium intake and any of the vascular outcomes. Participants in the highest compared to the lowest magnesium intake tertile demonstrated in fully adjusted cross-sectional analyses a PWV of −0.21 m/s (95% confidence interval −1.95, 1.52), a FMD of −0.03% (−0.89, 0.83) and in longitudinal analyses an IMT of 0.01 mm (−0.03, 0.06), an Aix of 0.70% (−1.69, 3.07) and an odds ratio of 0.84 (0.23, 3.11) for PAD CONCLUSION: We did not find associations between dietary magnesium intake and multiple markers of vascular structure and function, in either cross-sectional or longitudinal analyses. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00394-021-02667-0

    Identifying the optimal donor for natural killer cell adoptive therapy to treat paediatric B- and T-cell acute lymphoblastic leukaemia.

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    Objectives: Natural killer (NK) cells are an attractive source of cells for an 'off the shelf' cellular therapy because of their innate capacity to target malignant cells, and ability to be transferred between donors and patients. However, since not all NK cells are equally effective at targeting cancer, selecting the right donor for cellular therapy is critical for the success of the treatment. Recently, cellular therapies utilising NK cells from cytomegalovirus (CMV)-seropositive donors have been explored. However, whether these NK cells are the best source to treat paediatric acute lymphoblastic leukaemia (ALL) remains unclear. Methods: Using a panel of patient-derived paediatric B- and T-ALL, we assessed the ability of NK cells from 49 healthy donors to mount an effective functional response against these two major subtypes of ALL. Results: From this cohort, we have identified a pool of donors with superior activity against multiple ALL cells. While these donors were more likely to be CMV+, we identified multiple CMVneg donors within this group. Furthermore, NK cells from these donors recognised B- and T-ALL through different activating receptors. Dividing functional NK cells into 29 unique subsets, we observed that within each individual the same NK cell subsets dominated across all ALL cells. Intriguingly, this occurred despite the ALL cells in our panel expressing different combinations of NK cell ligands. Finally, we can demonstrate that cellular therapy products derived from these superior donors significantly delayed leukaemia progression in preclinical models of ALL. Conclusions: We have identified a pool of superior donors that are effective against a range of ALL cells, representing a potential pool of donors that can be used as an adoptive NK cell therapy to treat paediatric ALL

    The Diagnostic Accuracy of Cystoscopy for Detecting Bladder Cancer in Adults Presenting with Haematuria:A Systematic Review from the European Association of Urology Guidelines Office

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    Context: Haematuria can be macroscopic (visible haematuria [VH]) or microscopic (nonvisible haematuria [NVH]), and may be caused by a number of underlying aetiologies. Currently, in case of haematuria, cystoscopy is the standard diagnostic tool to screen the entire bladder for malignancy. Objective: The objective of this systematic review is to determine the diagnostic test accuracy of cystoscopy (compared with other tests, eg, computed tomography, urine biomarkers, and urine cytology) for detecting bladder cancer in adults. Evidence acquisition: A systematic review of the literature was performed according to the Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy and Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) extension for diagnostic test accuracy studies’ checklist. The MEDLINE, Embase, Cochrane CENTRAL, and Cochrane CDSR databases (via Ovid) were searched up to July 13, 2022. The population comprises patients presenting with either VH or NVH, without previous urological cancers. Two reviewers independently screened all articles, searched reference lists of retrieved articles, and performed data extraction. The risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). Evidence synthesis: Overall, nine studies were included in the qualitative analysis. Seven out of nine included trials covered the use of cystoscopy in comparison with radiological imaging. Overall, sensitivity of cystoscopy ranged from 87% to 100%, specificity from 64% to 100%, positive predictive value from 79% to 98%, and negative predictive values between 98% and 100%. Two trials compared enhanced or air cystoscopy versus conventional cystoscopy. Overall sensitivity of conventional white light cystoscopy ranged from 47% to 100% and specificity from 93.4% to 100%.Conclusions: The true accuracy of cystoscopy for the detection of bladder cancer within the context of haematuria has not been studied extensively, resulting in inconsistent data regarding its performance for patients with haematuria. In comparison with imaging modalities, a few trials have prospectively assessed the diagnostic performance of cystoscopy, confirming very high accuracy for cystoscopy, exceeding the diagnostic value of any other imaging test. Patient summary: Evidence of tests for detecting bladder cancer in adults presenting with haematuria (blood in urine) was reviewed. The most common test used was cystoscopy, which remains the current standard for diagnosing bladder cancer.</p

    Whole-genome sequencing illuminates the evolution and spread of multidrug-resistant tuberculosis in Southwest Nigeria.

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    Nigeria has an emerging problem with multidrug-resistant tuberculosis (MDR-TB). Whole-genome sequencing was used to understand the epidemiology of tuberculosis and genetics of multi-drug resistance among patients from two tertiary referral centers in Southwest Nigeria. In line with previous molecular epidemiology studies, most isolates of Mycobacterium tuberculosis from this dataset belonged to the Cameroon clade within the Euro-American lineage. Phylogenetic analysis showed this clade was undergoing clonal expansion in this region, and suggests that it was involved in community transmission of sensitive and multidrug-resistant tuberculosis. Five patients enrolled for retreatment were infected with pre-extensively drug resistant (pre-XDR) due to fluoroquinolone resistance in isolates from the Cameroon clade. In all five cases resistance was conferred through a mutation in the gyrA gene. In some patients, genomic changes occurred in bacterial isolates during the course of treatment that potentially led to decreased drug susceptibility. We conclude that inter-patient transmission of resistant isolates, principally from the Cameroon clade, contributes to the spread of MDR-TB in this setting, underscoring the urgent need to curb the spread of multi-drug resistance in this region
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