V0405 Dra:A New Deep and Low Mass Ratio Contact Binary with Extremely Fast Decrease in the Orbital Period

V0405 Dra is a W UMa-type binary star.Based on the TESS data,we have conducted an orbital period study and performed a light curve analysis for the system.The orbital period study reveals that the O-C curve for V0405 Dra exhibits secular decrease at an extremely high rate of d P/dt=-2.71×10^(-6)day year^(-1),along with periodic variations characterized by an amplitude of A_(3)=0.0032 day and a period of P_(3)=1.413 years.The orbital periodic change is possibly due to the light-travel time effect resulting from an additional third body in the system,for which we estimate a minimum mass of M_(3)=0.77M_(⊙).By employing the 2013 version of the Wilson-Devinney(W-D)method to synthesize a light curve,we derived photometric solutions indicating that V0405 Dra is a new deep(f=68.7%)and low-mass ratio(q=0.175)contact binary.The fast decrease in its orbital period is likely caused by mass transfer from the more massive primary star to the less massive secondary star,or due to angular momentum loss.With further mass transfer and loss of angular momentum,the binary will gradually evolve into a tighter contact configuration,eventually leading to a merger into a single star,following the evolutionary paths suggested for such deep and low mass ratio contact binaries.

Acute recurrent cerebral infarction caused by moyamoya disease complicated with adenomyosis:A case report

BACKGROUND Moyamoya disease is essentially an ischemic cerebrovascular disease.Here,we describe a case of acute recurrent cerebral infarction caused by moyamoya disease with concurrent adenomyosis which,to our knowledge,is the first in the literature.A literature review is also presented.CASE SUMMARY A 38-year-old female presented to the Research and Treatment Center of Moyamoya Disease in our hospital with"left limb weakness"as the main symptom.She was diagnosed with acute cerebral infarction and moyamoya disease through magnetic resonance imaging and digital subtraction angiography.Prior to this,she had experienced a prolonged menstrual period of one-month duration.This was investigated and adenomyosis was diagnosed.After passing the acute cerebral infarction phase,the patient underwent surgery for adenomyosis followed by combined cerebral revascularization.During the postoperative follow-up,improvements of the perfusion imaging stage and modified Rankin Scale were observed.A review of the literature showed only 16 reported cases of gynecological diseases complicated with stroke.The clinical characteristics,pathogenesis,therapeutic effects,and long-term prognosis of these cases have been studied and discussed.CONCLUSION In patients with moyamoya disease,early management of gynecological-related bleeding disorders is essential to prevent the complications of cerebral events.

Disaster effects of climate change in High Mountain Asia:State of art and scientific challenges Disaster effects of climate change in High Mountain Asia:State of art and scientific challenges

High Mountain Asia(HMA)shows a remarkable warming tendency and divergent trend of regional precipitation with enhanced meteorological extremes.The rapid thawing of the HMA cryosphere may alter the magnitude and frequency of nature hazards.We reviewed the influence of climate change on various types of nature hazards in HMA region,including their phenomena,mechanisms and impacts.It reveals that:1)the occurrences of extreme rainfall,heavy snowfall,and drifting snow hazards are escalating;accelerated ice and snow melting have advanced the onset and increased the magnitude of snowmelt floods;2)due to elevating trigger factors,such as glacier debuttressing and the rapid shift of thermal and hydrological regime of bedrock/snow/ice interface or subsurface,the mass flow hazards including bedrock landslide,snow avalanche,ice-rock avalanches or glacier detachment,and debris flow will become more severe;3)increased active-layer detachment and retrogressive thaw slumps slope failures,thaw settlement and thermokarst lake will damage many important engineering structures and infrastructure in permafrost region;4)multi-hazards cascading hazard in HMA,such as the glacial lake outburst flood(GLOF)and avalanche-induced mass flow may greatly enlarge the destructive power of the primary hazard by amplifying its volume,mobility,and impact force;and 5)enhanced slope instability and sediment supply in the highland areas could impose remote catastrophic impacts upon lowland regions,and threat hydropower security and future water shortage.In future,ongoing thawing of HMA will profoundly weaken the multiple-phase material of bedrock,ice,water,and soil,and enhance activities of nature hazards.Compounding and cascading hazards of high magnitude will prevail in HMA.As the glacier runoff overpasses the peak water,low flow or droughts in lowland areas downstream of glacierized mountain regions will became more frequent and severe.Addressing escalating hazards in the HMA region requires tackling scientific challenges,including understanding multiscale evolution and formation mechanism of HMA hazard-prone systems,coupling thermo‒hydro‒mechanical processes in multi-phase flows,predicting catastrophes arising from extreme weather and climate events,and comprehending how highland hazards propagate to lowlands due to climate change.