199 research outputs found
The importance of fuel variability on the performance of solid oxide cells operating on H2/CO2 mixtures from biohydrogen processes
Enjoyment of life predicts reduced type 2 diabetes incidence over 12 years of follow-up: findings from the English Longitudinal Study of Ageing
BACKGROUND: Subjective well-being appears to be associated with reduced risk of type 2 diabetes (T2D). However, it is unknown whether this association is similar across different types of well-being. We examined the relationship between hedonic and eudaimonic well-being and incident T2D, and explored the role of sociodemographic, behavioural and clinical factors in these associations. METHODS: We used data from 4134 diabetes-free participants from the English Longitudinal Study of Ageing (mean age =64.97). Enjoyment of life and purpose in life were assessed using items from the CASP-19 to reflect hedonic and eudaimonic well-being, respectively. Participants reported T2D diagnosis over 12 years. We used Cox proportional hazards regression analyses and also explored the percentage of association explained by different covariates. RESULTS: Results revealed a protective role for enjoyment of life in T2D rate adjusting for sociodemographic (age, sex, wealth, ethnicity, marital status), behavioural (physical activity, smoking, alcohol consumption, body mass index) and clinical (hypertension, coronary heart disease and glycated haemoglobin) characteristics (HR =0.93, p=0.021, 95% CI (0.87, 0.99)). Sociodemographic, behavioural and clinical factors accounted for 27%, 27% and 18% of the association, respectively. The relationship between purpose in life and T2D was non-significant (adjusted HR =0.92, p=0.288, 95% CI (0.78, 1.08)). CONCLUSION: This study illustrates how the link between subjective well-being and T2D varies between well-being components. It also demonstrates that sociodemographic, behavioural and clinical factors partially explain this association. Intervention studies examining whether changes in enjoyment of life can help delay T2D onset are warranted
Ca II H and K Chromospheric Emission Lines in Late K and M Dwarfs
We have measured the profiles of the Ca II H and K chromospheric emission
lines in 147 main sequence stars of spectral type M5-K7 (0.30-0.55 solar
masses) using multiple high resolution spectra obtained during six years with
the HIRES spectrometer on the Keck 1 telescope. Remarkably, the average FWHM,
equivalent widths, and line luminosities of Ca II H and K increase by a factor
of 3 with increasing stellar mass over this small range of stellar masses. We
fit the H and K lines with a double Gaussian model to represent both the
chromospheric emission and the non-LTE central absorption. Most of the sample
stars display a central absorption that is typically redshifted by ~0.1 km/s
relative to the emission, but the nature of this velocity gradient remains
unknown. The FWHM of the H and K lines increase with stellar luminosity,
reminiscent of the Wilson-Bappu effect in FGK-type stars. Both the equivalent
widths and FWHM exhibit modest temporal variability in individual stars. At a
given value of M_v, stars exhibit a spread in both the equivalent width and
FWHM of Ca II H and K, due both to a spread in fundamental stellar parameters
including rotation rate, age, and possibly metallicity, and to the spread in
stellar mass at a given M_v. The K line is consistently wider than the H line,
as expected, and its central absorption is more redshifted, indicating that the
H and K lines form at slightly different heights in the chromosphere where the
velocities are slightly different. The equivalent width of H-alpha correlates
with Ca II H and K only for stars having Ca II equivalent widths above ~2
angstroms, suggesting the existence of a magnetic threshold above which the
lower and upper chromospheres become thermally coupled.Comment: 40 pages including 12 figures and 17 pages of tables, accepted for
publication in PAS
Dysregulated responses to stress and weight in people with type 2 diabetes
OBJECTIVE: Dysregulated stress responsivity has been linked with weight gain in healthy samples. However, the relationship between disturbances in stress-related biology and changes in weight in people with type 2 diabetes (T2D) is unclear. METHOD: A total of 66 participants with T2D underwent laboratory stress-testing in 2011-2012. Cardiovascular, neuroendocrine and inflammatory responses to standardised mental stress were assessed, and Body Mass Index (BMI) was measured. Participants self-reported information on BMI in 2019. Associations between stress-related biological responses and BMI at follow-up were modelled using linear regression adjusting for age, sex, resting biological levels and baseline BMI. RESULTS: Blunted diastolic blood pressure reactivity (B = -0.092, 95% CI -0.177; -0.007, p = 0.034) as well as poorer systolic blood pressure (B = -0.050, 95% CI -0.084; - 0.017, p = 0.004), diastolic blood pressure (B = -0.068, 95% CI -0.132; -0.004, p = 0.034) and heart rate (B = -0.122, 95% CI -0.015;-0.230, p = 0.027) recovery post-stress were associated with higher BMI 7.5 years later. Greater interleukin-1 receptor antagonist (B = 16.93, 95% CI 6.20; 27.67, p = 0.003) and monocyte chemoattractant protein-1 reactivity (B = 0.04, 95% CI 0.002; 0.084, p = 0.041) were associated with weight gain. No significant associations were detected for interleukin-6 or laboratory cortisol measures. CONCLUSION: Disturbances in stress-related biology may promote weight gain in people with T2D. Research with a larger sample size is required to explore associations between stress responsivity and BMI in people with T2D
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CCN measurements at the Princess Elisabeth Antarctica research station during three austral summers
For three austral summer seasons (2013-2016, each from December to February) aerosol particles arriving at the Belgian Antarctic research station Princess Elisabeth (PE) in Dronning Maud Land in East Antarctica were characterized. This included number concentrations of total aerosol particles (N CN ) and cloud condensation nuclei (N CCN ), the particle number size distribution (PNSD), the aerosol particle hygroscopicity, and the influence of the air mass origin on N CN and N CCN . In general N CN was found to range from 40 to 6700cm -3 , with a median of 333cm -3 , while N CCN was found to cover a range between less than 10 and 1300cm-3 for supersaturations (SSs) between 0.1% and 0.7%. It is shown that the aerosol is dominated by the Aitken mode, being characterized by a significant amount of small, and therefore likely secondarily formed, aerosol particles, with 94% and 36% of the aerosol particles smaller than 90 and â35nm, respectively. Measurements of the basic meteorological parameters as well as the history of the air masses arriving at the measurement station indicate that the station is influenced by both marine air masses originating from the Southern Ocean and coastal areas around Antarctica (marine events - MEs) and continental air masses (continental events - CEs). CEs, which were defined as instances when the air masses spent at least 90% of the time over the Antarctic continent during the last 10 days prior to arrival at the measurements station, occurred during 61% of the time during which measurements were done. CEs came along with rather constant N CN and N CCN values, which we denote as Antarctic continental background concentrations. MEs, however, cause large fluctuations in N CN and N CCN , with low concentrations likely caused by scavenging due to precipitation and high concentrations likely originating from new particle formation (NPF) based on marine precursors. The application of HYSPLIT back trajectories in form of the potential source contribution function (PSCF) analysis indicate that the region of the Southern Ocean is a potential source of Aitken mode particles. On the basis of PNSDs, together with N CCN measured at an SS of 0.1%, median values for the critical diameter for cloud droplet activation and the aerosol particle hygroscopicity parameter ° were determined to be 110nm and 1, respectively. For particles larger than Äâ°110nm the Southern Ocean together with parts of the Antarctic ice shelf regions were found to be potential source regions. While the former may contribute sea spray particles directly, the contribution of the latter may be due to the emission of sea salt aerosol particles, released from snow particles from surface snow layers, e.g., during periods of high wind speed, leading to drifting or blowing snow. The region of the Antarctic inland plateau, however, was not found to feature a significant source region for aerosol particles in general or page276 for cloud condensation nuclei measured at the PE station in the austral summer
AtChem (version 1), an open-source box model for the Master Chemical Mechanism
AtChem is an open-source zero-dimensional box model for atmospheric chemistry. Any general set of chemical reactions can be used with AtChem, but the model was designed specifically for use with the Master Chemical Mechanism (MCM, http://mcm.york.ac.uk/, last access: 16 January 2020). AtChem was initially developed within the EUROCHAMP project as a web application (AtChem-online, https://atchem.leeds.ac.uk/webapp/, last access: 16 January 2020) for modelling environmental chamber experiments; it was recently upgraded and further developed into a stand-alone offline version (AtChem2), which allows the user to run complex and long simulations, such as those needed for modelling of intensive field campaigns, as well as to perform batch model runs for sensitivity studies. AtChem is installed, set up and configured using semi-automated scripts and simple text configuration files, making it easy to use even for inexperienced users. A key feature of AtChem is that it can easily be constrained to observational data which may have different timescales, thus retaining all the information contained in the observations. Implementation of a continuous integration workflow, coupled with a comprehensive suite of tests and version control software, makes the AtChem code base robust, reliable and traceable. The AtChem2 code and documentation are available at https://github.com/AtChem/ (last access: 16 January 2020) under the open-source MIT License
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