The Light and Period Variations of the Eclipsing Binary AA Ursae Majoris

We present new multiband CCD photometry for AA UMa made on 8 nights between January and March 2009; the $R$ light curves are the first ever compiled. Historical light curves, as well as ours, display partial eclipses and inverse O'Connell effects with Max I fainter than Max II. Among possible spot models, a cool spot on either of the component stars and its variability with time permit good light-curve representations for the system. A total of 194 eclipse timings over 81 yrs, including our five timings, were used for ephemeris computations. We found that the orbital period of the system has varied due to a periodic oscillation overlaid on an upward parabolic variation. The continuous period increase at a fractional rate of $+$1.3$\times$10$^{-10}$ is consistent with that calculated from the W-D code and can be interpreted as a thermal mass transfer from the less to the more massive secondary star at a rate of 6.6$\times$10$^{-8}$ M$_\odot$ yr$^{-1}$. The periodic component is in satisfactory accord with a light-time effect due to an unseen companion with a period of 28.2 yrs, a semi-amplitude of 0.007 d, and a minimum mass of $M_3 \sin i_3$=0.25 $M_\odot$ but this period variation could also arise from magnetic activity.Comment: 23 pages, including 5 figures and 8 tables, accepted for publication in PAS

Radar-based nowcasting by combining centroid tracking and motion vector of convective storm

Póster presentado en: 3rd European Nowcasting Conference, celebrada en la sede central de AEMET en Madrid del 24 al 26 de abril de 2019

Bioprinting of three-dimensional dentin-pulp complex with local differentiation of human dental pulp stem cells

Numerous approaches have been introduced to regenerate artificial dental tissues. However, conventional approaches are limited when producing a construct with three-dimensional patient-specific shapes and compositions of heterogeneous dental tissue. In this research, bioprinting technology was applied to produce a three-dimensional dentin-pulp complex with patient-specific shapes by inducing localized differentiation of human dental pulp stem cells within a single structure. A fibrin-based bio-ink was designed for bioprinting with the human dental pulp stem cells. The effects of fibrinogen concentration within the bio-ink were investigated in terms of printability, human dental pulp stem cell compatibility, and differentiation. The results show that micro-patterns with human dental pulp stem cells could be achieved with more than 88% viability. Its odontogenic differentiation was also regulated according to the fibrinogen concentration. Based on these results, a dentin-pulp complex having patient-specific shape was produced by co-printing the human dental pulp stem cell-laden bio-inks with polycaprolactone, which is a bio-thermoplastic used for producing the overall shape. After culturing with differentiation medium for 15 days, localized differentiation of human dental pulp stem cells in the outer region of the three-dimensional cellular construct was successfully achieved with localized mineralization. This result demonstrates the possibility to produce patient-specific composite tissues for tooth tissue engineering using three-dimensional bioprinting technology

Improvements of motion vector in variational echo tracking technique by correction of initial guess

Póster presentado en: 3rd European Nowcasting Conference, celebrada en la sede central de AEMET en Madrid del 24 al 26 de abril de 2019

Photometric Properties of the Near-contact Binary GW Geminorum

New multiband CCD photometry is presented for the eclipsing binary GW Gem; the $RI$ light curves are the first ever compiled. Four new minimum timings have been determined. Our analysis of eclipse timings observed during the past 79 years indicates a continuous period increase at a fractional rate of +(1.2$\pm$0.1)$\times10^{-10}$, in excellent agreement with the value $+1.1\times10^{-10}$ calculated from the Wilson-Devinney binary code. The new light curves display an inverse O'Connell effect increasing toward longer wavelengths. Hot and cool spot models are developed to describe these variations but we prefer a cool spot on the secondary star. Our light-curve synthesis reveals that GW Gem is in a semi-detached, but near-contact, configuration. It appears to consist of a near-main-sequence primary star with a spectral type of about A7 and an evolved early K-type secondary star that completely fills its inner Roche lobe. Mass transfer from the secondary to the primary component is responsible for the observed secular period change.Comment: 20 pages, including 5 figures and 6 tables, accepted for publication in PAS

Far-Ultraviolet Cooling Features of the Antlia Supernova Remnant

We present far-ultraviolet observations of the Antlia supernova remnant obtained with Far-ultraviolet IMaging Spectrograph (FIMS, also called SPEAR). The strongest lines observed are C IV 1548,1551 and C III 977. The C IV emission of this mixed-morphology supernova remnant shows a clumpy distribution, and the line intensity is nearly constant with radius. The C III 977 line, though too weak to be mapped over the whole remnant, is shown to vary radially. The line intensity peaks at about half the radius, and drops at the edge of the remnant. Both the clumpy distribution of C IV and the rise in the C IV to C III ratio towards the edge suggest that central emission is from evaporating cloudlets rather than thermal conduction in a more uniform, dense medium.Comment: 9 pages, 4 figures, will be published in ApJ December 1, 2007, v670n2 issue. see http://astro.snu.ac.kr/~jhshinn/ms.pd

An Empirical Study on the Effects of Walking Time on Knee Joint Pain Based on Korea National Health and Nutrition Examination Survey Data

Objectives: It is generally reported that walking has a positive effect on knee joint pain. However, since previous studies have focused on small patient data and simple average comparisons, we proceed with more sophisticated empirical research using public data. Since the knee joint pain itself can be considered very important in terms of preventative medicine, we analyze that use of big data to identify its effect on knee joint pain. Methods: The present study used a logistic regression analysis and analyzed the effect of walking time on knee joint pain in the activities of daily living based on data from the 6th 2013–2014 Korea National Health and Nutrition Examination Survey. Results: Smoking, Drinking and Sedentary time has no statistically significance on knee joint pain. And walking (moderate, high) has been shown to reduce the risk of knee joint pain. Conclusion: The results confirmed that walking time had a positive effect on the prevalence of knee joint pain. However, individuals with moderate-intensity walking time and those with high-intensity walking time had different effects on preventing knee joint pain

Short Term Effect and Safety of Antidiuretic Hormone in the Patients with Nocturia

Purpose To investigate the short-term safety of antidiuretic hormone in elderly patients with nocturnal polyuria, focus on hyponatremia and others electrolytes disturbances and to assess short-term effects on nocturnal urine output and number of nocturnal voids. Methods Between June 2005 and August 2006, a total of 34 patients with nocturnal polyuria were orally administered 0.2 mg desmopressin tablet at bedtime for two weeks. Serum sodium, others electrolytes, urine sodium and urine osmolarity were assessed in the third days, one week and two weeks after treatment with desmopressin and compared adult group (<65 years of age) with elderly group (≥65 years of age). We assessed the effect of desmopressin using a frequency-volume charts and analysed. Results In total 34 patients (20 adult, 14 elderly) were analyzed. Desmopressin treatment did not significantly change serum and urine electrolytes include soduim concentration in elderly patients comparied with adult patients. Serum sodium concentration below normal range was recorded in 2 patients in elderly group, but no serious adverse events occurred and recovered without sequelae. The mean number of nocturnal voids decresed (54% reduction) and nocturnal urine output decreased (57% reduction) after using desmopressin. Conclusions Desmopressin was well tolerated and effective in elderly patients with nocturnal polyuria without clinically significant hyponatremia