10,041 research outputs found
The human salivary microbiome exhibits temporal stability in bacterial diversity
The temporal variability of the human microbiome may be an important factor in determining its relationship with health and disease. In this study, the saliva of 40 participants was collected every 2 months over a one-year period to determine the temporal variability of the human salivary microbiome. Salivary pH and 16S rRNA gene copy number were measured for all participants, with the microbiome of 10 participants assessed through 16S rRNA amplicon sequencing. In February 2013, 16S rRNA gene copy number was significantly (P < 0.001) higher, with individual changes between time points significant (P = 0.003). Salivary pH levels were significantly (P < 0.001) higher in December 2012 than in October 2012 and February 2013, with significant (P < 0.001) individual variations seen throughout. Bacterial α-diversity showed significant differences between participants (P < 0.001), but not sampling periods (P = 0.801), and a significant positive correlation with salivary pH (R(2) = 7.8%; P = 0.019). At the phylum level, significant differences were evident between participants in the Actinobacteria (P < 0.001), Bacteroidetes (P < 0.001), Firmicutes (P = 0.008), Fusobacteria (P < 0.001), Proteobacteria (P < 0.001), Synergistetes (P < 0.001) and Spirochaetes (P = 0.003) phyla. This study charted the temporal variability of the salivary microbiome, suggesting that bacterial diversity is stable, but that 16S rRNA gene copy number may be subject to seasonal flux
Energy density of foods and beverages in the Australian food supply: influence of macronutrients and comparison to dietary intake.
OBJECTIVES: The energy density (ED) of the diet is considered an important determinant of total energy intake and thus energy balance and weight change. We aimed to compare relationships between ED and macronutrient content in individual food and beverage items as well as population diet in a typical Western country. DESIGN: Nutrient data for 3673 food items and 247 beverage items came from the Australian Food and Nutrient database (AusNut). Food and beverage intake data came from the 1995 Australian National Nutrition Survey (a 24-h dietary recall survey in 13 858 people over the age of 2). Relationships between ED and macronutrient and water content were analysed by linear regression with 95% prediction bands. RESULTS: For both individual food items and population food intake, there was a positive relationship between ED and percent energy as fat and negative relationships between ED and percent energy as carbohydrate and percent water by weight. In all cases, there was close agreement between the slopes of the regression lines between food items and dietary intake. There were no clear relationships between ED and macronutrient content for beverage items. Carbohydrate (mostly sucrose) contributed 91, 47, and 25% of total energy for sugar-based, fat-based, and alcohol-based beverages respectively. CONCLUSIONS: The relationship between ED and fat content of foods holds true across both population diets and individual food items available in the food supply in a typical Western country such as Australia. As high-fat diets are associated with a high BMI, population measures with an overall aim of reducing the ED of diets may be effective in mediating the growing problem of overweight and obesity
The cross helicity at the solar surface by simulations and observations
The quasilinear mean-field theory for driven MHD turbulence leads to the
result that the observed cross helicity may directly yield the
magnetic eddy diffusivity \eta_{T} of the quiet Sun. In order to model the
cross helicity at the solar surface, magnetoconvection under the presence of a
vertical large-scale magnetic field is simulated with the nonlinear MHD code
NIRVANA. The very robust result of the calculations is that \simeq 2
independent of the applied magnetic field amplitude. The
correlation coefficient for the cross helicity is about 10%. Of similar
robustness is the finding that the rms value of the magnetic perturbations
exceeds the mean-field amplitude (only) by a factor of five. The characteristic
helicity speed u_{\eta} as the ratio of the eddy diffusivity and the density
scale height for an isothermal sound velocity of 6.6 km/s proves to be 1 km/s
for weak fields. This value well coincides with empirical results obtained from
the data of the HINODE satellite and the Swedish 1-m Solar Telescope (SST)
providing the cross helicity component . Both simulations and
observations thus lead to a numerical value of \eta_{T} \simeq 10^12 cm^2 /s as
characteristic for the surface of the quiet Sun.Comment: 6 pages, 6 figure
Multimodal agent interfaces and system architectures for health and fitness companions
Multimodal conversational spoken dialogues using physical and virtual agents provide a potential interface to motivate and support users in the domain of health and fitness. In this paper we present how such multimodal conversational Companions can be implemented to support their owners in various pervasive and mobile settings. In particular, we focus on different forms of multimodality and system architectures for such interfaces
Vortices in simulations of solar surface convection
We report on the occurrence of small-scale vortices in simulations of the
convective solar surface. Using an eigenanalysis of the velocity gradient
tensor, we find the subset of high vorticity regions in which the plasma is
swirling. The swirling regions form an unsteady, tangled network of filaments
in the turbulent downflow lanes. Near-surface vertical vortices are underdense
and cause a local depression of the optical surface. They are potentially
observable as bright points in the dark intergranular lanes. Vortex features
typically exist for a few minutes, during which they are moved and twisted by
the motion of the ambient plasma. The bigger vortices found in the simulations
are possibly, but not necessarily, related to observations of granular-scale
spiraling pathlines in "cork animations" or feature tracking.Comment: 11 pages, 13 figures, accepted for publication in A&A, complementary
movies at http://www.mps.mpg.de/homes/moll/strudel/papermovies
Velocity Dispersion of Dissolving OB Associations Affected by External Pressure of Formation Environment
This paper presents a possible way to understand dissolution of OB
associations (or groups). Assuming rapid escape of parental cloud gas from
associations, we show that the shadow of the formation environment for
associations can be partially imprinted on the velocity dispersion at their
dissolution. This conclusion is not surprising as long as associations are
formed in a multiphase interstellar medium, because the external pressure
should suppress expansion caused by the internal motion of the parental clouds.
Our model predicts a few km s as the internal velocity dispersion.
Observationally, the internal velocity dispersion is km s which
is smaller than our prediction. This suggests that the dissipation of internal
energy happens before the formation of OB associations.Comment: 6 pages. AJ accepte
The internet: to regulate or not regulate
This submission was prepared in response to a call for evidence launched on 29 March 2018 by the House of Lords Select Committee on Communications entitled “The Internet: To Regulate or Not to Regulate?”. The broad inquiry sought evidence to explore how the regulation of the internet should be improved, and to consider whether online platforms which mediate individuals’ use of the internet have sufficient accountability and transparency, and whether they use fair and effective processes to moderate content. This collaborative response, prepared on behalf of NINSO (The Northumbria Internet & Society Research Interest Group), provides recommendations in relation to the wide range of issues raised by the Committee. The key themes that are highlighted by NINSO to be addressed by any reform are effective user education and the power imbalance between the platform and user. NINSO recommends that an empirical, holistic, evidence-based approach should be applied which is tailored appropriately to the size and resources of the platform as well as the context of the situation
Lithium abundances along the RGB: FLAMES-GIRAFFE spectra of a large sample of low-mass Bulge stars
Context: A small number of K-type giants on the red giant branch (RGB) is
known to be very rich in lithium (Li). This fact is not accounted for by
standard stellar evolution theory. The exact phase and mechanism of Li
enrichment is still a matter of debate. Aims: Our goal is to probe the
abundance of Li along the RGB, from its base to the tip, to confine Li-rich
phases that are supposed to occur on the RGB. Methods: For this end, we
obtained medium-resolution spectra with the FLAMES spectrograph at the VLT in
GIRAFFE mode for a large sample of 401 low-mass RGB stars located in the
Galactic bulge. The Li abundance was measured in the stars with a detectable Li
670.8 nm line by means of spectral synthesis with COMARCS model atmospheres. A
new 2MASS (J-K) - Teff calibration from COMARCS models is presented in the
Appendix. Results: Thirty-one stars with a detectable Li line were identified,
three of which are Li-rich according to the usual criterion (). The stars are distributed all along the RGB, not concentrated in
any particular phase of the red giant evolution (e.g. the luminosity bump or
the red clump). The three Li-rich stars are clearly brighter than the
luminosity bump and red clump, and do not show any signs of enhanced mass loss.
Conclusions: We conclude that the Li enrichment mechanism cannot be restricted
to a clearly defined phase of the RGB evolution of low-mass stars
(M\sim1M_{\sun}), contrary to earlier suggestions from disk field stars.Comment: 6 pages (14 with appendix), 5 figures (1 in appendix), accepted for
publication in A&
Revisiting Ruddick: Feminism, pacifism and non-violence
This article explores feminist contentions over pacifism and non-violence in the contextof the Greenham Common Peace Camp in the 1980s and later developments offeminist Just War Theory. We argue that Sara Ruddick’s work puts feminist pacifism, its radical feminist critics and feminist just war theory equally into question. Although Ruddick does not resolve the contestations within feminism over peace, violence and the questions of war, she offers a productive way of holding the tension between them. In our judgment, her work is helpful not only for developing a feminist political response to the threats and temptations of violent strategies but also for thinking through the question of the relation between violence and politics as such
A New Association of Post-T Tauri Stars Near The Sun
Observing ROSAT sources in 20 x 25 deg centered at the high latitude active
star ER Eri, we found evidences for a new young nearby association (~30Myr
at~60pc), the Horologium Association (HorA), formed by at least 10 probable and
6 possible members, some being Post-T Tauri stars. We examine several
requirements that characterize a young association and they, together, create a
strong evidence for the reality of the HorA. In fact, the Li line intensities
are between those of the oldest classical T Tauri stars and the ones of the
Local Association stars. The space velocities of the HorA relative to the Sun,
U= -9.5+/-1.0, V = -20.9 +/- 1.1, W = -2.1 +/- 1.9, are not far from those of
the Local Association. We suggest that some hotter and non-X-ray active stars,
with similar space velocities, could be massive members of the HorA, among
them, the nearby Be star Achernar. The maximum of the mass distribution
function of the HorA is around 0.8 solar masses. At its distance, the projected
size of the HorA, ~50 pc, would be larger than our surveyed area and many other
members could have been missed. We also observed 3 control regions, two at
northern and southern galactic latitudes and a third one in the known TW Hya
Association (TWA), and the properties and distribution of their young stars
strengthen the reality of the HorA. Contrary to the TWA, the only known
binaries in the HorA are 2 very wide systems. The HorA is much more isolated
from clouds and older than the TWA and could give some clues about the lifetime
of the disks around T Tauri stars. Actually, none of the proposed members is an
IRAS source indicating an advanced stage of the evolution of their accreting
disks. ER Eri itself was found to be a RS CVn-like system.Comment: 25 pages, 5 eps figures, to appear in Astron.
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