We report on a discovery of “negative” superhumps during the 2011 January superoutburst of ER UMa. During the superoutburst, which started on 2011 January 16, we detected negative superhumps having a ...period of 0.062242(9) d, shorter than its orbital period by 2.2%. No evidence of a positive superhump was detected during this observation. This finding indicates that the disk exhibited retrograde precession during this superoutburst, contrary to all other known cases of superoutbursts. The duration of this superoutburst was shorter than those of ordinary superoutbursts, and the interval of its normal outbursts was longer than those of ordinary normal outbursts of ER UMa. We suggest the possibility that such unusual outburst properties are likely to be a result of a disk tilt, which is supposed to be a cause of negative superhumps; the tilted disk could prevent the disk from being filled with materials in the outmost region, which is supposed to be responsible for long-duration superoutbursts in ER UMa-type dwarf novae. This discovery signifies the importance of the classical prograde precession in sustaining long-duration superoutbursts. Furthermore, the presence of pronounced negative superhumps in this system with a high mass-transfer rate supports the hypothesis that hydrodynamical lift is the cause of the disk tilt.
Continuing the project described by Kato et al. (2009, PASJ, 61, S395), we collected the times of superhump maxima for 51 SU UMa-type dwarf novae, mainly observed during the 2010–2011 season. ...Although most of the new data for systems with short superhump periods basically confirmed the findings by Kato et al. (ibid.) and Kato et al. (2010, PASJ, 62, 1525), the long-period system GX Cas showed an exceptionally large positive-period derivative. An analysis of public Kepler data of V344 Lyr and V1504 Cyg yielded less-striking stage transitions. In V344 Lyr, there was a prominent secondary component growing during the late stage of superoutbursts, and this component persisted for at least two more cycles of successive normal outbursts. We also investigated the superoutburst of two conspicuous eclipsing objects: HT Cas and the WZ Sge-type object SDSS J080434.20
$+$
510349.2. Strong beat phenomena were detected in both objects, and late-stage superhumps in the latter object had an almost constant luminosity during repeated rebrightenings. The WZ Sge-type object SDSS J133941.11
$+$
484727.5 showed a phase reversal around the rapid fading from the superoutburst. The object showed a prominent beat phenomenon, even after the end of the superoutburst. A pilot study of superhump amplitudes indicated that the amplitude of superhumps is strongly correlated with the orbital period, and the dependence on the inclination is weak in systems with inclinations smaller than 80
$^{\circ}$
.
We carried out photometric observations of the SU UMa-type dwarf nova ER UMa during 2011 and 2012, which showed the existence of persistent negative superhumps even during the superoutburst. We ...performed a two-dimensional period analysis of its light curves by using a method called “least absolute shrinkage and selection operator” (Lasso) and the “phase dispersion minimization” (PDM) analysis, and found that the period of negative superhumps systematically changed between a superoutburst and the next superoutburst. The trend of the period change can be interpreted as a reflection of the change of the disk radius. This change is in agreement with the one predicted by the thermal tidal instability model. The normal outburst during a supercycle showed a general trend that the rising rate to its maximum becomes slower as the next superoutburst is approaching. The change can be interpreted as the consequence of the increased gas-stream flow into the inner region of the disk as a result of the tilted disk. Some of superoutbursts were found to be triggered by a precursor normal outburst when the positive superhump appeared to develop. The positive and negative superhumps coexisted during the superoutburst. Positive superhumps were prominent only for four or five days after the supermaximum, while the signal of negative superhumps became stronger after the middle phase of the superoutburst plateau. A simple combination of the positive and negative superhumps was found to be insufficient for reproduction of the complex profile variation. We were able to detect the developing phase of positive superhumps (stage A superhumps) for the first time in ER UMa-type dwarf novae. Using the period of stage A superhumps, we obtained a mass ratio of 0.100(15), which indicates that ER UMa is on the ordinary evolutional track of cataclysmic variable stars.
Background.
Extralevator abdominoperineal excision is associated with a high incidence of perineal wound complications. There is no uniform standard for choosing the method for pelvic floor ...reconstruction after extralevator abdominoperineal excision.
The purpose
of the study was to compare the results of extralevator abdominoperineal excisions of the rectum using various methods of perineal wound closure.
Materials and Methods
. Between 2014 and 2018, 120 patients underwent extralevator abdominoperineal excisions of the rectum using various options for closure of the pelvic floor. The patients were divided into 3 groups. Group I patients (n=64) underwent simple plasty of the peritoneal wound. Group II patients (n=43) underwent myoplasty using the gluteus maximus muscle. Group III patients (n=13) underwent myoplasty using the rectus abdominis muscle. The incidence of perineal wound complications in the early postoperative period was assessed.
Results.
The total number of perineal wound complications in Group I, II and III was 33 (51.5 %), 13 (30.2 %), and 6 (46.1 %), respectively. Grade IIIA-IIIB complications according to the Clavien-Dindo classification were observed in 25 % of Group I patients, in 18.6 % of Group II patients and in 7.7 % of Group II patients. Postoperative perineal wound complications occurred more often in Group I patients after simple plasty than in Group II and III patients after myoplasty (51.5 % versus 30.2 %). However, perineal wound complications were observed more often in Group III than in Group II (46.1 % versus 30.2 %, respectively). No significant differences in the frequency of complications between 3 groups were found.
Conclusion.
Using various options for closure of the pelvic floor after extralevator abdominoperineal excisions of the rectum, there was a tendency to reduction in the incidence of grade IIIA-IIIB perineal wound complications.
The article deals with the illustrations archive of the Peter the Great Museum of Anthropology and Ethnography, the Russian Academy of Sciences (MAE RAS); known simply as Kunstkamera. The Museum ...boasts an extensive photographic collection. In total, the Museum’s illustrations archive contains more than ten collections on Korea, including photographs and slides, as well as post cards depicting scenes from traditional ways of life. They also provide us with illustrations covering Seoul, its neighboring towns and views of Korean villages in remote provinces. The oldest collections date back to the second half of the 19th century. The pictures of this period are of particular interest for researchers. The central theme of the article focuses on the three collections of pictures. The first, collected by Karl I. Weber (1841-?), who served as the first Russian chargé d’affaires to Korea, illustrates the initial period of active relations between Russia and Korea. The second, collected by the talented publicist, historian, Orientalist and philologist, Sergey N. Syromyatnikov (1864-1933), who visited Korea twice in 1897 and 1898, illustrates the warmest and most intense period of Russo-Korean relations. The third collection of pictures, taken during the expedition under Alexander I. Zvegintsov (1869-1915) to the northern part of Korea in the autumn of 1898, illustrates Russia’s geopolitical interest in the region. The material under consideration, which arrived at the MAE RAS between the end of the 19th and the middle of the 20th century, has not yet been fully investigated by specialists. This article is the first attempt to conduct a systematic investigation of the Kunstkamera collection. The paper presents a primary description of the collections, attempts to date the photographs, seeks to systematize and verify material in relation to the collectors, currently scattered in various resources, and provides a brief description of the historical context which defines the ethnographical and historical value of the individual collections. Several pictures are published for the first time.
The multi-site photometric observations of MN Dra were made over 77 nights in August-November, 2009. The total exposure was 433 hours. During this time the binary underwent two superoutbursts and ...five normal outbursts. During the course of first superoutburst period of positive superhumps decreased with extremely large \(\dot P = -1.5 \times 1.0^{-4}\) for SU UMa-like dwarf novae, confirming known behavior of MN Dra 1. Between the superoutbursts MN Dra displayed negative superhumps. Their period changed cyclically around 0.096-day value.
We carried out the photometric observations of the SU UMa-type dwarf nova ER UMa during 2011 and 2012, which showed the existence of persistent negative superhumps even during the superoutburst. We ...performed two-dimensional period analysis of its light curves by using a method called "least absolute shrinkage and selection operator" (Lasso) and "phase dispersion minimization" (PDM) analysis, and we found that the period of negative superhumps systematically changed between a superoutburst and the next superoutburst. The trend of the period change can beinterpreted as reflecting the change of the disk radius. This change of the disk radius is in good agreement with the predicted change of the disk radius by the thermal-tidal instability (TTI) model. The normal outbursts within a supercycle showed a general trend that the rising rate to maximum becomes slower as the next superoutburst approaches. The change can be interpreted as the consequence of the increased gas-stream flow onto the inner region of the disk as the result of the tilted disk. Some of the superoutbursts were found to be triggered by a precursor normal outburst when the positive superhumps appeared to develop. The positive and negative superhumps co-existed during the superoutburst. The positive superhumps were prominent only during four or five days after the supermaximum, while the signal of the negative superhumps became strong after the middle phase of the superoutburst plateau. A simple combination of the positive and negative superhumps was found to be insufficient in reproducing the complex profile variation. We were able to detect the developing phase of positive superhumps (stage A superhumps) for the first time in ER UMa-type dwarf novae. Using the period of stage A superhumps, we obtained a mass ratio of 0.100(15), which indicates that ER UMa is on the ordinary evolutional track of CVs.
Continuing the project described by Kato et al. (2009a, arXiv:0905.1757), we collected times of superhump maxima for SU UMa-type dwarf novae mainly observed during the 2012-2013 season. We found ...three objects (V444 Peg, CSS J203937 and MASTER J212624) having strongly positive period derivatives despite the long orbital period (Porb). By using the period of growing stage (stage A) superhumps, we obtained mass ratios for six objects. We characterized nine new WZ Sge-type dwarf novae. We made a pilot survey of the decline rate of slowly fading part of SU UMa-type and WZ Sge-type outbursts. The decline time scale was found to generally follow the expected Porb^(1/4) dependence and WZ Sge-type outbursts also generally follow this trend. There are some objects which show slower decline rates, and we consider these objects good candidates for period bouncers. We also studied unusual behavior in some objects, including BK Lyn which made a transition from an ER UMa-type state to the novalike (standstill) state in 2013 and unusually frequent occurrence of superoutbursts in NY Ser and CR Boo. We applied least absolute shrinkage and selection operator (Lasso) power spectral analysis, which has been proven to be very effective in analyzing the Kepler data, to ground-based photometry of BK Lyn and detected the dramatic disappearance of the signal of negative superhumps in 2013. We suggested that the mass-transfer rates did not vary strongly between the ER UMa-type state and novalike state in BK Lyn, and this transition was less likely caused by a systematic variation of the mass-transfer rate.
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