285 research outputs found
Book Review: First and Second Language Use in Asian EFL (R. Forman, 2016)
published_or_final_versio
The VMC Survey. V. First results for Classical Cepheids
The VISTA Magellanic Cloud (VMC, PI M.R. Cioni) survey is collecting deep
Ks-band time-series photometry of the pulsating variable stars hosted by the
system formed by the two Magellanic Clouds (MCs) and the "bridge" connecting
them. In this paper we present the first results for Classical Cepheids, from
the VMC observations of two fields in the Large Magellanic Cloud (LMC). The VMC
Ks-band light curves of the Cepheids are well sampled (12-epochs) and of
excellent precision. We were able to measure for the first time the Ks
magnitude of the faintest Classical Cepheids in the LMC (Ks\sim17.5 mag), which
are mostly pulsating in the First Overtone (FO) mode, and to obtain FO
Period-Luminosity (PL), Period-Wesenheit (PW), and Period-Luminosity-Color
(PLC) relations, spanning the full period range from 0.25 to 6 day. Since the
longest period Cepheid in our dataset has a variability period of 23 day, we
have complemented our sample with literature data for brighter F Cepheids. On
this basis we have built a PL relation in the Ks band that, for the first time,
includes short period pulsators, and spans the whole range from 1.6 to 100 days
in period. We also provide the first ever empirical PW and PLC relations using
the (V-Ks) color and time-series Ks photometry. The very small dispersion
(\sim0.07 mag) of these relations makes them very well suited to study the
three-dimensional (3D) geometry of the Magellanic system. The use of "direct"
(parallax- and Baade-Wesselink- based) distance measurements to both Galactic
and LMC Cepheids, allowed us to calibrate the zero points of the PL, PW, and
PLC relations obtained in this paper, and in turn to estimate an absolute
distance modulus of (m-M)0=18.46\pm0.03 for the LMC. This result is in
agreement with most of the latest literature determinations based on Classical
Cepheids.Comment: 12 pages, 7 figures: MNRAS in pres
HAT-P-13: a multi-site campaign to detect the transit of the second planet in the system
A possible transit of HAT-P-13c has been predicted to occur on 2010 April 28.
Here we report on the results of a multi-site campaign that has been organised
to detect the event. CCD photometric observations have been carried out at five
observatories in five countries. We reached 30% time coverage in a 5 days
interval centered on the suspected transit of HAT-P-13c. Two transits of
HAT-P-13b were also observed. No transit of HAT-P-13c has been detected while
the campaign was on. By a numerical experiment with 10^5 model systems we
conclude that HAT-P-13c is not a transiting exoplanet with a significance level
from 65% to 72%, depending on the planet parameters and the prior assumptions.
We present two times of transit of HAT-P-13b ocurring at BJD 2455141.5522 +-
0.0010 and BJD 2455249.4508 +- 0.0020. The TTV of HAT-P-13b is consistent with
zero within 0.001 days. The refined orbital period of HAT-P-13b is 2.916293 +-
0.000010 days.Comment: 5 pages, 4 figures, to be accepted by A&
Properties of M31. II: A Cepheid disk sample derived from the first year of PS1 PAndromeda data
We present a sample of Cepheid variable stars towards M31 based on the first
year of regular M31 observations of the PS1 survey in the r_P1 and i_P1
filters. We describe the selection procedure for Cepheid variable stars from
the overall variable source sample and develop an automatic classification
scheme using Fourier decomposition and the location of the instability strip.
We find 1440 fundamental mode (classical \delta) Cep stars, 126 Cepheids in the
first overtone mode, and 147 belonging to the Population II types. 296 Cepheids
could not be assigned to one of these classes and 354 Cepheids were found in
other surveys. These 2009 Cepheids constitute the largest Cepheid sample in M31
known so far and the full catalog is presented in this paper. We briefly
describe the properties of our sample in its spatial distribution throughout
the M31 galaxy, in its age properties, and we derive an apparent
period-luminosity relation (PLR) in our two bands. The Population I Cepheids
nicely follow the dust pattern of the M31 disk, whereas the 147 Type II
Cepheids are distributed throughout the halo of M31. We outline the time
evolution of the star formation in the major ring found previously and find an
age gradient. A comparison of our PLR to previous results indicates a curvature
term in the PLR
Interstitial pulmonary fibrosis in a Malaysian captive Asian elephant (Elephas maximus)
A 14-year-old female captive Asian elephant in a Malaysian z
oo with a history of positive sero-reactivity to Elephant TB STAT-PAK assay was humanely euthanized due to chronic weight loss and poor response to treatment. Postmortem revealed generalized congestion and emphysematous lungs. Microscopically, there were severe pulmonary emphysema, eosinophilic hyaline membrane and infiltration of mature fibrocytes in the alveolar walls. Based on the histopathological findings interstitial pulmonary
fibrosis was diagnosed. The possible cause of which although not completely known, is most likely due to hypersensitivity. The allergic reaction could have been caused by exposure to antigens of avian origin or the
Mycobacterium gilvum, an non-tuberculous
mycobacterium (NTM), isolated from the lung. This is the second case reported in elephants globally, thought it has been well studied in humans and reported in horses. Providing good husbandry for elephants in captivity is important to reduce the occurrence of such condition
Evaluation of the potential for virus dispersal during hand drying: a comparison of three methods
Aims
To use a MS2 bacteriophage model to compare three hand-drying methods, paper towels (PT), a warm air dryer (WAD) and a jet air dryer (JAD), for their potential to disperse viruses and contaminate the immediate environment during use.
Methods and Results
Participants washed their gloved hands with a suspension of MS2 bacteriophage and hands were dried with one of the three hand-drying devices. The quantity of MS2 present in the areas around each device was determined using a plaque assay. Samples were collected from plates containing the indicator strain, placed at varying heights and distances and also from the air. Over a height range of 0.15-1.65 m, the JAD dispersed an average of >60 and >1300-fold more plaque-forming units (pfu) compared to the WAD and PT (P 20 and >190-fold more pfu in total compared to WAD and PT at all distances tested up to 3 m (P 50 and >100-fold more pfu compared to the WAD and PT (P <0.001), respectively.
Conclusions
Use of the JAD lead to significantly greater and further dispersal of MS2 bacteriophage from artificially contaminated hands when compared to the WAD and PT.
Significance and Impact of Study
The choice of hand drying device should be considered carefully in areas where infection prevention concerns are paramount, such as healthcare settings and the food industry
Adiposity impacts cognitive function in Asian populations: an epidemiological and Mendelian Randomization study.
BACKGROUND: Obesity and related metabolic disturbances including diabetes, hypertension and hyperlipidemia predict future cognitive decline. Asia has a high prevalence of both obesity and metabolic disease, potentially amplifying the future burden of dementia in the region. We aimed to investigate the impact of adiposity and metabolic risk on cognitive function in Asian populations, using an epidemiological analysis and a two-sample Mendelian Randomization (MR) study. METHODS: The Health for Life in Singapore (HELIOS) Study is a population-based cohort of South-East-Asian men and women in Singapore, aged 30-84 years. We analyzed 8769 participants with metabolic and cognitive data collected between 2018 and 2021. Whole-body fat mass was quantified with Dual X-Ray Absorptiometry (DEXA). Cognition was assessed using a computerized cognitive battery. An index of general cognition ' g ' was derived through factor analysis. We tested the relationship of fat mass indices and metabolic measures with ' g ' using regression approaches. We then performed inverse-variance-weighted MR of adiposity and metabolic risk factors on ' g ', using summary statistics for genome-wide association studies of BMI, visceral adipose tissue (VAT), waist-hip-ratio (WHR), blood pressure, HDL cholesterol, triglycerides, fasting glucose, HbA1c, and general cognition. FINDINGS: Participants were 58.9% female, and aged 51.4 (11.3) years. In univariate analysis, all 29 adiposity and metabolic measures assessed were associated with ' g ' at P < 0.05. In multivariable analyses, reduced ' g ' was consistently associated with increased visceral fat mass index and lower HDL cholesterol (P < 0.001), but not with blood pressure, triglycerides, or glycemic indices. The reduction in ' g ' associated with 1SD higher visceral fat, or 1SD lower HDL cholesterol, was equivalent to a 0.7 and 0.9-year increase in chronological age respectively (P < 0.001). Inverse variance MR analyses showed that reduced ' g ' is associated with genetically determined elevation of VAT, BMI and WHR (all P < 0.001). In contrast, MR did not support a causal role for blood pressure, lipid, or glycemic indices on cognition. INTERPRETATION: We show an independent relationship between adiposity and cognition in a multi-ethnic Asian population. MR analyses suggest that both visceral adiposity and raised BMI are likely to be causally linked to cognition. Our findings have important implications for preservation of cognitive health, including further motivation for action to reverse the rising burden of obesity in the Asia-Pacific region. FUNDING: The Nanyang Technological University-the Lee Kong Chian School of Medicine, National Healthcare Group, National Medical Research Council, Ministry of Education, Singapore
The complex case of V445 Lyr observed with Kepler: Two Blazhko modulations, a non-radial mode, possible triple mode RR Lyrae pulsation, and more
Rapid and strong changes in the Blazhko modulation of RR Lyrae stars, as they
have recently been detected in high precision satellite data, have become a
crucial topic in finding an explanation of the long-standing mystery of the
Blazhko effect. We present here an analysis of the most extreme case detected
so far, the RRab star V445 Lyr (KIC 6186029) which was observed with the Kepler
space mission. V445 Lyr shows very strong cycle-to-cycle changes in its Blazhko
modulation, which are caused both by a secondary long-term modulation period as
well as irregular variations. In addition to the complex Blazhko modulation,
V445 Lyr also shows a rich spectrum of additional peaks in the frequency range
between the fundamental pulsation and the first harmonic. Among those peaks,
the second radial overtone could be identified, which, combined with a
metallicity estimate of [Fe/H]=-2.0 dex from spectroscopy, allowed to constrain
the mass (0.55-0.65 M_sun) and luminosity (40-50 L_sun) of V445 Lyr through
theoretical Petersen diagrams. A non-radial mode as well as possibly the first
overtone are also excited. Furthermore, V445 Lyr shows signs of the period
doubling phenomenon and a long term period change. A detailed Fourier analysis
along with a study of the O-C variation of V445 Lyr is presented, and the
origin of the additional peaks and possible causes of the changes in the
Blazhko modulation are discussed. The results are then put into context with
those of the only other star with a variable Blazhko effect for which a long
enough set of high precision continuous satellite data has been published so
far, the CoRoT star 105288363.Comment: 19 pages, 20 figuers, accepted for publication in MNRA
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