ABSTRACT
This article reports quasi-continuous transiting events towards WD 1054–226 at d = 36.2 pc and V = 16.0 mag, based on simultaneous, high-cadence, multiwavelength imaging photometry using ...ULTRACAM over 18 nights from 2019 to 2020 March. The predominant period is 25.02 h and corresponds to a circular orbit with blackbody Teq = 323 K, where a planetary surface can nominally support liquid water. The light curves reveal remarkable night-to-night similarity, with changes on longer time-scales, and lack any transit-free segments of unocculted starlight. The most pronounced dimming components occur every 23.1 min – exactly the 65th harmonic of the fundamental period – with depths of up to several per cent, and no evident colour dependence. Myriad additional harmonics are present, as well as at least two transiting features with independent periods. High-resolution optical spectra are consistent with stable, photospheric absorption by multiple, refractory metal species, with no indication of circumstellar gas. Spitzer observations demonstrate a lack of detectable dust emission, suggesting that the otherwise hidden circumstellar disc orbiting WD 1054–226 may be typical of polluted white dwarfs, and detected only via favourable geometry. Future observations are required to constrain the orbital eccentricity, but even if periastron is near the Roche limit, sublimation cannot drive mass loss in refractory parent bodies, and collisional disintegration is necessary for dust production.
A group analysis of the second-order equation including the one-dimensional gas dynamics equations in Lagrangian coordinates as a particular case is performed. The use of Lagrangian coordinates makes ...it possible to consider the one-dimensional gas dynamics equations as a variational Euler-Lagrange equation with an appropriate Lagrangian. Conservation laws are derived with the use of the variational presentation and Noether’s theorem. A complete group classification of the Euler-Lagrange equation is obtained; as a result, 18 different classes can be identified.
The previous paper by the authors (Siriwat and Meleshko in Contin Mech Thermodyn 24:115–148,
2012
) was devoted to group analysis of one-dimensional nonisentropic equations of fluids with internal ...inertia. A direct approach was employed for finding the admitted Lie group. This approach allowed to perform a partial group classification of the considered equations with respect to a potential function. The present paper completes this group classification by an efficient algebraic method.
Driver exposure to particulate matter in Bangkok Jinsart, W.; Kaewmanee, C.; Inoue, M. ...
Journal of the Air & Waste Management Association (1995),
20/1/1/, Letnik:
62, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The aims of this study were to determine the particulate matter with aerodynamic diameters ≥2.5 μm (PM
2.5
) and 2.5-10 μm (PM
10-2.5
) exposure levels of drivers and to analyze the proportion of ...elemental carbon (EC) and organic carbon (OC) in PM
2.5
in Bangkok, Thailand. Four bus routes were selected. Measurements were conducted over 10 days in August (rainy season) 2008 and 8 days in January (dry season) 2009. The mean PM
2.5
exposure level of the Tuk-tuk drivers was 86 μg/m
3
in August and 198 μg/m
3
in January. The mean for the non-air-conditioned bus drivers was 63 μg/m
3
in August and 125 μg/m
3
in January. The PM
2.5
and PM
10-2.5
exposure levels of the drivers in January were approximately twice as high as those in August. The proportion of total carbon (TC) in PM
2.5
to the PM
2.5
level in August (0.97 ± 0.28 μg/m
3
) was higher than in January (0.65 ± 0.13 μg/m
3
). The proportion of OC in the TC of the PM
2.5
in August (0.51 ± 0.08 μg/m
3
) was similar to that in January (0.65 ± 0.07 μg/m
3
). The TC exposure by PM
2.5
in January (81 ± 30 μg/m
3
) remained higher than in August (56 ± 21 μg/m
3
). The mean level of OC in the PM
2.5
was 29 ± 13 μg/m
3
in August and 50 ± 24 μg/m
3
in January. In conclusion, the PM exposure level in Bangkok drivers was higher than that in the general environment, which was already high, and it varied with the seasons and vehicle type. This study also demonstrated that the major component of the PM was carbon, likely derived from vehicles.
The effect of cannibalism on an age-structured predator–prey system is studied. Three stable equilibrium states are found. Using a Hopf bifurcation analysis, it is found that the non washout steady ...state looses its stability as the cannibalism attack rate increases past a bifurcation point
S
c. The dependence of the bifurcation point on the other parameters in the model is found. It is shown that the trajectory of the solution spirals in for attack rates
S<
S
c and exhibits limit cycle behavior for
S>
S
c.
The ubiquity of high quality smartphones at affordable prices not only accelerated the social penetration in the global population but also promoted nontraditional usage of smartphones as ...point-of-care medical diagnostic devices, sensors, and portable digital microscopes. This paper reveals a simple, rapid, cost-effective, and template-free technique for mass-scale production of an elastomeric PDMS (ePDMS) planoconvex lens capable of converting a smartphone into a portable digital microscope. By taking advantage of the resistance to spreading of liquid by a sharp edge, highly stable spherical cap of viscous liquid PDMS (lPDMS) on a smooth PMMA circular disk was fabricated. The axisymmetric spreading of lPDMS under the gravitational force and interfacial tension force enable the formation of spherical cap with a certain radius of curvature. A thermal treatment at 80 °C for 30 min cured the spherical cap lPDMS into a bubble-free ePDMS planoconvex lens. Lenses with focal lengths of 55.2–3.4 mm could be reproducibly fabricated by adjusting the volume of dispensed lPDMSs and diameter of PMMA disks. High-resolution panoramic microscope images without a distortion of small cylindrical object could be constructed on-the-fly using the imbedded smartphone app. Applications of the smartphone digital microscope equipped with an ePDMS planoconvex lens for imaging of micro printings, gun shot residues, cylindrical objects, and bullet toolmarks were explored.
Atmospherically corrected surface reflectance (SR) products are used for reliable monitoring of land surfaces and are the standard products of Landsat sensors. Due to increased demand for SR ...products, a need exists to verify that the L2C2 (Level-2 Collection-2) SR products are precise and accurate. The Level-2 Collection 2 (L2C2) SR Product has processed satellite imagery data that correct for atmospheric effects such as absorption and scattering, providing a more accurate representation of Earth’s surface. The validation of SR products using ground truth measurement is essential. This study aims to develop and evaluate a validation methodology for satellite SR products. Thus, the Empirical Line Method (ELM) is used here for atmospheric validation of remotely sensed data. Validation is performed using the SR derived from ELM tied to ground truth measurement. Absolute surface reflectance models of Algodones Dunes and the Salton Sea located in North America Sonoran Desert are developed to extend the temporally limited ground truth measurements. This model can give ground truth reflectance in any time frame independent of time constraints. The result of the absolute surface reflectance model of Algodones Dunes indicates that the model predicts the response of Algodones Dunes with an average accuracy of 0.0041 and precision of 0.0063 and gives ground measurements across all multispectral between 350 and 2500 nm. For the Salton Sea, the model predicts the response of the Salton Sea with mean absolute error (MAE) of 0.0035 and gives ground measurements across all multispectral between 350 and 2500 nm. The ELM generates atmospheric coefficients (gain and bias), which are applied to an image to obtain SR. Validation results indicated that for L9-OLI-2, L8-OLI, and L5-TM-SR products, the RMSE range is 0.0019 to 0.0106, 0.0019 to 0.0148 and 0.0026 to 0.0045 reflectance unit, respectively, and accuracy is within 0.0038, 0.0022, and 0.0055 reflectance unit across all spectral bands of L9, L8, and L5, respectively. On average, the validation result showed a strong linear relation between the L2C2 SR products and ELM SR within 0.5 to 1 reflectance units. These results demonstrate the high accuracy and reliability of the L2C2 SR product, providing valuable information for a wide range of remote sensing applications, including land cover and land use mapping, vegetation monitoring, and climate change studies.
Ergonomic hazards are the most important cause of knee osteoarthritis (OA) in aged para rubber farmers. Ergonomic management comprising improvement of working conditions and muscle-strengthening ...exercise has been well documented in terms of workers' health benefit. However, those interventions were not adequate to sustain the advantage. Few studies have demonstrated the effect of integrating participatory ergonomic management (PEM) in non-weight-bearing exercise (NWE) and progressive resistance exercise (PRE), and none has focused on aged para rubber farmers with knee OA.
This study investigated the effect of PEM-NWE, PEM-PRE, and standard treatment (ST) on self-care and functional ability in the aged population.
A single-blinded, clustered randomized controlled trial was carried out. Participants (n=75) from three different communities in southern Thailand were randomly assigned to PEM-NWE, PEM-PRE, and ST. Self-care and functional ability (pain, stiffness, and physical function) were examined at baseline (B), during the intervention at Week 5 (W5), and after its completion at Week 9 (W9). Mean comparison of those outcomes over time was made using Generalized Linear Mixed Models (GLMMs).
Compared to the standard treatment, the means of both groups, PEM-NWE and PEM-PRE, were significantly increased in self-care and functional ability. However, no significant difference between PEM-NWE and PEM-PRE was found.
Either or both interventions should be incorporated into nursing practice in order to promote occupational health and enhance quality of work life for Thai aged farmers. Further study on their cost-effectiveness is highly recommended.
Physical activity (PA) is recognized as one of the core modifiable risk factors of noncommunicable diseases. However, little is known about PA in the Thai population, particularly in children. The ...report card (RC) project provided Thailand with an opportunity to assess PA behaviors in children. This paper summarizes the methodology, grading process, and the final grades of the Thai RC.
A school-based survey was conducted to collect data from a nationally representative sample of children aged 6 to 17 years. Survey results provided the primary source for the RC. Nine indicators were graded using the Global Matrix 2.0 framework. Grading was undertaken by a national committee comprising experts from key stakeholders.
Grades ranged from F to B. Overall PA and Sedentary Behaviors both received the grade D-. Organized Sport Participation scored a C. Active Play scored the grade F. Active Transport and support from Family and Peers were both graded B. School, Community, and Government indicators were scored C.
In Thai children, participation in PA and active play is very low; conversely, sedentary behaviors are high. These first data on patterns of activity for the Thailand RC will serve to guide national actions and advocacy aimed at increasing PA in children.
Myrobalan (Terminalia chebula) is known well for against microorganisms. The antimicrobial properties of different concentrations of ethanolic extracts of myrobalan (EEM) against foodborne ...microorganisms were evaluated. Myrobalan was extracted by using different concentrations of ethanol containing 70 and 95% ethanol (v/v). The antimicrobial activity of EEM against 14 strains of foodborne microorganisms were determined by minimum inhibitory concentrations (MIC) using agar dilution method. The gallic acid content of EEM from different concentrations of ethanol was analyzed by high performance liquid chromatography (HPLC). Results showed MIC values of EEM against foodborne microorganisms obtained by 70 and 95% ethanol ranged from 3.0-8.0 and 3.0-7.0 mg/ml, respectively. Gram-positive and Gram-negative bacteria were more resistant to EEM than yeast except for Vibrio parahaemolyticus. Among Gram-positive bacteria, lactic acid bacteria were more resistant to EEM than other Gram-positive bacteria. From HPLC spectrum, gallic acid was the main active compounds presented in EEM. It can be concluded that EEM has significant antimicrobial potential against foodborne microorganisms. Thus, EEM has a potential to use as natural antimicrobials for chemical substances replacement which is beneficial to food preservative purpose. PUBLICATION ABSTRACT
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