First R and I Lights and Their Photometric Analyses of GSC 02393-00680

We obtained complete $R$ and $I$ light curves of GSC 02393-00680 in 2008 and analyzed them with the 2003 version of the W-D code. It is shown that GSC 02393-00680 is a W-type shallow contact binary system with a high mass ratio $q=1.600$ and a degree of contact factor $f=5.0$. It will be a good example to check up on the TRO theory. A period investigation based on all available data suggests that the system has a small-amplitude period oscillation ($A_3=0.^{d}0030$; $T_3=1.92$years). This may indicate it has a moderate mass close third body, which is similar to XY Leo

Mesenchymal adenomatous polyposis coli plays critical and diverse roles in regulating lung development.

BackgroundAdenomatous polyposis coli (Apc) is a tumor suppressor that inhibits Wnt/Ctnnb1. Mutations of Apc will not only lead to familial adenomatous polyposis with associated epithelial lesions, but will also cause aggressive fibromatosis in mesenchymal cells. However, the roles of Apc in regulating mesenchymal cell biology and organogenesis during development are unknown.ResultsWe have specifically deleted the Apc gene in lung mesenchymal cells during early lung development in mice. Loss of Apc function resulted in immediate mesenchymal cell hyperproliferation through abnormal activation of Wnt/Ctnnb1, followed by a subsequent inhibition of cell proliferation due to cell cycle arrest at G0/G1, which was caused by a mechanism independent of Wnt/Ctnnb1. Meanwhile, abrogation of Apc also disrupted lung mesenchymal cell differentiation, including decreased airway and vascular smooth muscle cells, the presence of Sox9-positive mesenchymal cells in the peripheral lung, and excessive versican production. Moreover, lung epithelial branching morphogenesis was drastically inhibited due to disrupted Bmp4-Fgf10 morphogen production and regulation in surrounding lung mesenchyme. Lastly, lung mesenchyme-specific Apc conditional knockout also resulted in altered lung vasculogenesis and disrupted pulmonary vascular continuity through a paracrine mechanism, leading to massive pulmonary hemorrhage and lethality at mid-gestation when the pulmonary circulation should have started.ConclusionsOur study suggests that Apc in lung mesenchyme plays central roles in coordinating the proper development of several quite different cellular compartments including lung epithelial branching and pulmonary vascular circulation during lung organogenesis

Detection of Tidally Excited Oscillations in Kepler Heartbeat Stars

Heartbeat stars (HBSs) with tidally excited oscillations (TEOs) are ideal laboratories for studying the effect of equilibrium and dynamical tides. However, studies of TEOs in Kepler HBSs are rare due to {the need for better modeling of the equilibrium tide in light curves}. We revisit the HBSs reported by Li et al. {and study the TEOs in these HBSs based on the derived orbital parameters that could express the equilibrium tide.} We also compile a set of analysis procedures to examine the harmonic and anharmonic TEOs in their Fourier spectrum. The TEOs of 45 HBSs (excluding eight systems studied in previous works) have been determined and presented. 19 of them show prominent TEOs (the signal-to-noise ratio of the harmonics $S/N \ge 10$). The relation between the orbital eccentricities and the harmonic number of the TEOs shows a positive correlation. The relation between the orbital periods and the harmonic number also shows a positive correlation. Furthermore, the distribution of HBSs with TEOs in the Hertzsprung-Russell (H-R) diagram shows that TEOs are more visible in hot stars with surface temperatures $T$ $\gtrsim$ 6500 K. These samples may also be valuable targets for future studies of the effect of tidal action in eccentric orbits.Comment: submitted to Ap

Nine New Cataclysmic Variable Stars with Negative Superhumps

Negative superhumps (NSHs) are signals a few percent shorter than the orbital period of a binary star and are considered to originate from the reverse precession of the tilted disk. Based on TESS photometry, we find nine new cataclysmic variable stars (CVs) with NSHs. Three (ASAS J1420, TZ Per, and V392 Hya) of these stars similar to AH Her still have NSHs during dwarf nova outbursts, and the NSH amplitude varies with the outburst. The variation in the radius of the accretion disk partially explains this phenomenon. However, it does not explain the rebound of the NSH amplitude after the peak of the outburst and the fact that the NSH amplitude of the quiescence is sometimes not the largest, and it is necessary to combine the disk instability model (DIM) and add other ingredients. Therefore, we suggest that the variation of NSH amplitude with outburst can be an essential basis for studying the origin of NSHs and improving the DIM. The six ( ASASSN-V J1137, ASASSN-V J0611, 2MASS J0715, LAMOST J0925, ASASSN-17qj, and ZTF18acakuxo) remaining stars have been poorly studied, and for the first time we determine their orbital periods, NSHs and Superorbital signal (SOR) periods. The NSH periods and amplitudes of ASASSN-V J1137 and ASASSN-17qj vary with the SOR, and based on the comparison of the observations with the theory, we suggest that a single change in tilted disk angle does not explain the observations of the SOR and that other ingredients need to be considered as well.Comment: 23 pages, 11 figure

RW Doradus: A solar-type shallow contact binary with a new orbital period investigation

New CCD photometric light curves of the short-period (P = 0.285 d) eclipsing binary RW Dor are presented. The observations were performed with the PROMPT-8 robotic telescope at CTIO in Chile between 2015 March and 2017 March. Other eclipse timings were obtained from the 2.15 m JS telescope at CASLEO, San Juan, Argentina in 2011 December. Based on a light curve analysis, it is found that RW Dor is a W-type shallow contact binary with a fill-out factor f ∼ 11% and a high mass ratio q ∼ 1.587 (1/q = 0.63), where the hotter component is the less massive one (M1 ∼ 0.52 M and M2 ∼ 0.82 M). For orbital-period investigation, 15 new eclipse times and those previously published were compiled. O − C analysis with very weak evidence suggests that a long-term decrease in period with a rate of dP/dt = −9.61 × 10−9 d yr−1 is superimposed on a cyclic variation(A3 = 0.0054 d and P3 = 49.9 yr). The long-term decrease can be interpreted as mass transfer from the more massive component to the less massive one, or combined with angular momentum loss via magnetic braking. In addition, the marginal contact phase, high mass ratio (1/q > 0.4), and long-term decrease in period all suggest that RW Dor is a newly formed contact binary via Case A mass transfer, and it will evolve into a deepernormal contact binary. If the cyclic change is correct, the light travel-time effect via the presence of a cool third body will be a more plausible explanation for this.Fil: Sarotsakulchai, Thawicharat. University of Chinese Academy of Sciences; China. National Astronomical Research Institute of Thailand; Tailandia. Chinese Academy of Sciences; República de ChinaFil: Qian, Sheng Bang. Chinese Academy of Sciences; República de China. University of Chinese Academy of Sciences; ChinaFil: Soonthornthum, Boonrucksar. National Astronomical Research Institute of Thailand; TailandiaFil: Fernandez Lajus, Eduardo Eusebio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Liu, Nian Ping. Chinese Academy of Sciences; República de ChinaFil: Zhou, Xiao. Chinese Academy of Sciences; República de ChinaFil: Zhang, Jia. Chinese Academy of Sciences; República de ChinaFil: Liao, Wen Ping. Chinese Academy of Sciences; República de ChinaFil: Reichart, Daniel E.. University of North Carolina; Estados UnidosFil: Haislip, Joshua B.. University of North Carolina; Estados UnidosFil: Kouprianov, Vladimir V.. University of North Carolina; Estados UnidosFil: Poshyachinda, Saran. National Astronomical Research Institute of Thailand; Tailandi

RW Doradus: a solar-type shallow contact binary with a new orbital period investigation

New CCD photometric light curves of the short-period (P = 0.285 d) eclipsing binary RW Dor are presented. The observations were performed with the PROMPT-8 robotic telescope at CTIO in Chile between 2015 March and 2017 March. Other eclipse timings were obtained from the 2.15 m JS telescope at CASLEO, San Juan, Argentina in 2011 December. Based on a light curve analysis, it is found that RW Dor is a W-type shallow contact binary with a fill-out factor f ∼ 11% and a high mass ratio q ∼ 1.587 (1/q = 0.63), where the hotter component is the less massive one (M₁ ∼ 0.52 M⊙ and M₂ ∼ 0.82 M⊙). For orbital-period investigation, 15 new eclipse times and those previously published were compiled. O − C analysis with very weak evidence suggests that a long-term decrease in period with a rate of dP/dt = −9.61 × 10⁻⁹ d yr⁻¹ is superimposed on a cyclic variation (A₃ = 0.0054 d and P₃ = 49.9 yr). The long-term decrease can be interpreted as mass transfer from the more massive component to the less massive one, or combined with angular momentum loss via magnetic braking. In addition, the marginal contact phase, high mass ratio (1/q >0.4), and long-term decrease in period all suggest that RW Dor is a newly formed contact binary via Case A mass transfer, and it will evolve into a deeper normal contact binary. If the cyclic change is correct, the light travel-time effect via the presence of a cool third body will be a more plausible explanation for thisInstituto de Astrofísica de La Plat