The female reproductive system consists of the ovaries,the female gonads,and the reproductive tract organs of the fallopian tubes,uterus,cervix,and vagina.It functions to provide hormonal support and anatomical struct...The female reproductive system consists of the ovaries,the female gonads,and the reproductive tract organs of the fallopian tubes,uterus,cervix,and vagina.It functions to provide hormonal support and anatomical structure for the production of new offspring.A number of endogenous and exogenous factors can impact female reproductive health and fertility,including genetic vulnerability,medications,environmental exposures,age,nutrition,and diseases.To date,due to the ethical concerns of using human subjects in biomedical research,the majority of studies use in vivo animal models and 2D cell/tissue culture models to study female reproduction.However,the complexity and species difference of the female reproductive system in humans make it difficult to compare to those of animals.Moreover,the monolayered cells cultured on flat plastics or glass lose their 3D architecture as well as the physical and/or biochemical contacts with other cells in vivo.Further,all reproductive organs do not work alone but interconnect with each other and also with non-reproductive organs to support female reproductive,endocrine,and systemic health.These facts suggest that there is an urgent and unmet need to develop representative,effective,and efficient in vitro models for studying human female reproduction.The prodigious advancements of bioengineering(e.g.,biomaterials,3D printing,and organ-on-a-chip)allow us to study female reproduction in an entirely new way.Here,we review recent advances that use bioengineering methods to study female reproduction,including the bioengineering models of the ovary,fallopian tube,uterus,embryo implantation,placenta,and reproductive disease.展开更多
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM),consisting of two microsatellites,is designed to detect gamma-ray bursts associated with gravitational-wave events.Here,we introduce th...Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM),consisting of two microsatellites,is designed to detect gamma-ray bursts associated with gravitational-wave events.Here,we introduce the real-time burst alert system of GECAM,with the adoption of the BeiDou-3 short message communication service.We present the post-trigger operations,the detailed ground-based analysis,and the performance of the system.In the first year of the in-flight operation,GECAM was triggered by 42 gamma-ray bursts.The GECAM real-time burst alert system has the ability to distribute the alert within~1 minute after being triggered,which enables timely follow-up observations.展开更多
With a high rate of infertility, it is important to understand the context of fertility and family planning in China, to inform the necessity of supportive care. A literature review was undertaken to explore the socie...With a high rate of infertility, it is important to understand the context of fertility and family planning in China, to inform the necessity of supportive care. A literature review was undertaken to explore the societal constructs informing perspectives of childbearing, family planning and infertility, alongside Chinese considerations of fertility treatments, including assisted reproductive technologies and fertility counselling. In China, childbearing attitudes and behaviours are shaped by tensions between traditional cultural values of the filial piety originating from Confucianism, the history of strict family planning policy, the recent termination of one-child policy and the socioeconomic circumstance. For infertile Chinese individuals, the inability to meet these childbearing expectations gives rise to significant pressure and consequent psychological distress, particularly depressive symptoms. Demographic factors such as gender, education, income and geographical location have been found to influence prevalence and degree of depression in infertile Chinese men and women. These difficulties are compounded by barriers of cultural acceptance, legislative restrictions and availability of resources for alternative options such as adoption and surrogacy. It is important that these fertility sociocultural factors are taken into consideration when assisting Chinese patients to access and utilise fertility treatment services.展开更多
The prompt emission mechanism of gamma-ray bursts(GRBs)is still unclear,and the time-resolved spectral analysis of GRBs is a powerful tool for studying their underlying physical processes.We performed a detailed time-...The prompt emission mechanism of gamma-ray bursts(GRBs)is still unclear,and the time-resolved spectral analysis of GRBs is a powerful tool for studying their underlying physical processes.We performed a detailed time-resolved spectral analysis of 78 bright long GRB samples detected by Fermi/Gamma-ray Burst Monitor.A total of 1490 spectra were obtained and their properties were studied using a typical Band-shape model.First,the parameter distributions of the time-resolved spectrum are given as follows:the low-energy spectral indexα~-0.72,high-energy spectral indexβ~2.42,the peak energy E_(p)~221.69 keV,and the energy flux F~7.49×10^(-6)erg cm^(-2)s^(-1).More than 80%of the bursts exhibit the hardest low-energy spectral indexα_(max),exceeding the synchrotron limit(-2/3).Second,the evolution patterns of a and E_(p)were statistically analyzed.The results show that for multi-pulse GRBs the intensity-tracking pattern is more common than the hard-to-soft pattern in the evolution of both E_(p)andα.The hard-to-soft pattern is generally shown in single-pulse GRBs or in the initial pulse of multi-pulse GRBs.Finally,we found a significant positive correlation between F and E_(p),with half of the samples exhibiting a positive correlation between F andα.We discussed the spectral evolution of different radiation models.The diversity of spectral evolution patterns indicates that there may be more than one radiation mechanism occurring in the GRB radiation process,including photo spheric radiation and synchrotron radiation.However,it may also involve only one radiation mechanism,but more complicated physical details need to be considered.展开更多
We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846-031 during its outburst in 2019 with the observations of Insight-HXMT,NICER and MAXI.This outburst can be class...We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846-031 during its outburst in 2019 with the observations of Insight-HXMT,NICER and MAXI.This outburst can be classified roughly into four different states.Type-C quasi-periodic oscillations(QPOs)observed by NICER(about 0.1-6 Hz)and Insight-HXMT(about 0.7-8 Hz)are also reported in this work.Meanwhile,we study various physical quantities related to QPO frequency.The QPO rms-frequency relationship in the energy band 1-10 keV indicates that there is a turning pointing in frequency around2 Hz,which is similar to that of GRS 1915+105.A possible hypothesis for the relationship above may be related to the inclination of the source,which may require a high inclination to explain it.The relationships between QPO frequency and QPO rms,hardness,total fractional rms and count rate have also been found in other transient sources,which can indicate that the origin of type-C QPOs is non-thermal.展开更多
Pulsar search is always the basis of pulsar navigation,gravitational wave detection and other research topics.Currently,the volume of pulsar candidates collected by the Five-hundred-meter Aperture Spherical radio Tele...Pulsar search is always the basis of pulsar navigation,gravitational wave detection and other research topics.Currently,the volume of pulsar candidates collected by the Five-hundred-meter Aperture Spherical radio Telescope(FAST)shows an explosive growth rate that has brought challenges for its pulsar candidate filtering system.Particularly,the multi-view heterogeneous data and class imbalance between true pulsars and non-pulsar candidates have negative effects on traditional single-modal supervised classification methods.In this study,a multi-modal and semi-supervised learning based on a pulsar candidate sifting algorithm is presented,which adopts a hybrid ensemble clustering scheme of density-based and partition-based methods combined with a feature-level fusion strategy for input data and a data partition strategy for parallelization.Experiments on both High Time Resolution Universe SurveyⅡ(HTRU2)and actual FAST observation data demonstrate that the proposed algorithm could excellently identify pulsars:On HTRU2,the precision and recall rates of its parallel mode reach0.981 and 0.988 respectively.On FAST data,those of its parallel mode reach 0.891 and 0.961,meanwhile,the running time also significantly decreases with the increment of parallel nodes within limits.Thus,we can conclude that our algorithm could be a feasible idea for large scale pulsar candidate sifting for FAST drift scan observation.展开更多
Fast and reliable localization of high-energy transients is crucial for characterizing the burst properties and guiding the follow-up observations.Localization based on the relative counts of different detectors has b...Fast and reliable localization of high-energy transients is crucial for characterizing the burst properties and guiding the follow-up observations.Localization based on the relative counts of different detectors has been widely used for all-sky gamma-ray monitors.There are two major methods for this count distribution localization:χ^(2)minimization method and the Bayesian method.Here we propose a modified Bayesian method that could take advantage of both the accuracy of the Bayesian method and the simplicity of the χ^(2)method.With comprehensive simulations,we find that our Bayesian method with Poisson likelihood is generally more applicable for various bursts than the χ^(2)method,especially for weak bursts.We further proposed a location-spectrum iteration approach based on the Bayesian inference,which could alleviate the problems caused by the spectral difference between the burst and location templates.Our method is very suitable for scenarios with limited computation resources or timesensitive applications,such as in-flight localization software,and low-latency localization for rapidly follow-up observations.展开更多
Realtime trigger and localization of bursts are the key functions of GECAM,an all-sky gamma-ray monitor launched on 2020 December 10.We developed a multifunctional trigger and localization software operating in the CP...Realtime trigger and localization of bursts are the key functions of GECAM,an all-sky gamma-ray monitor launched on 2020 December 10.We developed a multifunctional trigger and localization software operating in the CPU of the GECAM Electronic Box.This onboard software has the following features:high trigger efficiency for real celestial bursts with a suppression of false triggers caused by charged particle bursts and background fluctuation,dedicated localization algorithm optimized for both short and long bursts,and low time latency of the trigger information which is downlinked through the Global Short Message Communication service of the global BeiDou navigation system.This paper provides a detailed description of the design and development of the trigger and localization software system for GECAM.It covers the general design,workflow,the main functions,and the algorithms used in the system.The paper also includes on-ground trigger tests using simulated gamma-ray bursts generated by a dedicated X-ray tube,as well as an overview of the performance for real celestial bursts during its in-orbit operation.展开更多
In this paper,we presented the 23.3 yr of pulsar timing results of PSR J1456-6413 based on the observations of Parkes 64 m radio telescope.We detected two new glitches at MJD 57093(3)and 59060(12)and confirmed its fir...In this paper,we presented the 23.3 yr of pulsar timing results of PSR J1456-6413 based on the observations of Parkes 64 m radio telescope.We detected two new glitches at MJD 57093(3)and 59060(12)and confirmed its first glitch at MJD 54554(10).The relative sizes(Δν/ν)of these two new glitches are 0.9×10^(-9)and 1.16×10^(-9),respectively.Using the“Cholesky”timing analysis method,we have determined its position,proper motion,and two-dimensional transverse velocities from the data segments before and after the second glitch,respectively.Furthermore,we detected exponential recovery behavior after the first glitch,with a recovery timescale of approximately 200 days and a corresponding exponential recovery factor Q of approximately 0.15(2),while no exponential recovery was detected for the other two glitches.More interestingly,we found that the leading component of the integral pulse profile after the second glitch became stronger,while the main component became weaker.Our results will expand the sample of pulsars with magnetosphere fluctuation triggered by the glitch event.展开更多
The Gravitational wave burst high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)is a dedicated mission for monitoring high-energy transients.Here we report the design of the GECAM Scientific Ground Segment(...The Gravitational wave burst high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)is a dedicated mission for monitoring high-energy transients.Here we report the design of the GECAM Scientific Ground Segment(GSGS)in terms of the scientific requirements,including the architecture,the external interfaces,the main function,and workflow.Judging from the analysis and verification results during the commissioning phase,the GSGS functions well and is able to monitor the status of the payloads,adjust the parameters,develop the scientific observation plans,generate the scientific data products,analyze the data,etc.Thus,the on-orbit operation and scientific researches of GECAM are guaranteed.展开更多
The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)mission is designed to monitor the Gamma-Ray Bursts(GRBs)associated with gravitational waves and other high-energy transient sources...The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)mission is designed to monitor the Gamma-Ray Bursts(GRBs)associated with gravitational waves and other high-energy transient sources.The mission consists of two microsatellites which are planned to operate at the opposite sides of the Earth.Each GECAM satellite could detect and localize GRBs in about 8 keV-5 MeV with its 25 Gamma-Ray Detectors(GRDs).In this work,we report the in-flight energy calibration of GRDs using the characteristic gamma-ray lines in the background spectra,and show their performance evolution during the commissioning phase.Besides,a preliminary cross-calibration of energy response with Fermi GBM data is also presented,validating the energy response of GRDs.展开更多
Fast radio bursts(FRBs) are highly dispersed millisecond-duration radio bursts,[1,2]of which the physical origin is still not fully understood. FRB 20201124A is one of the most actively repeating FRBs. In this paper, ...Fast radio bursts(FRBs) are highly dispersed millisecond-duration radio bursts,[1,2]of which the physical origin is still not fully understood. FRB 20201124A is one of the most actively repeating FRBs. In this paper, we present the collection of 1863 burst dynamic spectra of FRB 20201124A measured with the Five-hundred-meter Aperture Spherical radio Telescope(FAST). The current collection, taken from the observation during the FRB active phase from April to June 2021, is the largest burst sample detected for any FRB so far. The standard PSRFITs format is adopted, including dynamic spectra of the burst, and the time information of the dynamic spectra, in addition, mask files help readers to identify the pulse positions are also provided. The dataset is available in Science Data Bank, with the link https://www.doi.org/10.57760/sciencedb.j00113.00076.展开更多
[Objectives] This study was conducted to explore the effects of different N application rates and densities on the growth and development of direct-seeding rape as well as on its yield.[Methods] A field experiment was...[Objectives] This study was conducted to explore the effects of different N application rates and densities on the growth and development of direct-seeding rape as well as on its yield.[Methods] A field experiment was carried out by setting five N fertilizer treatments and three density levels.[Results] Increasing seeding density and N application rate could improve the seed yield of rape. The suitable N application rate for the three densities were calculated using the fitted fertilizer efficiency models, respectively, to be 186.77, 221.35 and 236.14 kg/hm^2, at which the yields were the highest. The results showed that in this area, the seeding density of direct-seeding rape could be selected in the range of 6.0×10^5-7.5×10^5 plants/hm^2, and the suitable N application rate could be in the range of 221.35-236.14 kg/hm^2.[Conclusions] This study provides a theoretical basis for the maximization of spatial resource and efficient utilization of fertilizer.展开更多
As one of three primary scientific payloads of Insight-Hard X-ray Modulation Telescope(Insight-HXMT),the High Energy Xray telescope(HE)consists of 18 Nal/CsI phoswich detectors,and the CsI detectors can detect gamma-r...As one of three primary scientific payloads of Insight-Hard X-ray Modulation Telescope(Insight-HXMT),the High Energy Xray telescope(HE)consists of 18 Nal/CsI phoswich detectors,and the CsI detectors can detect gamma-rays that penetrate the satellite from all directions,with an energy range of about 60 keV to 3.2 MeV and a total geometric area of about 5100 cm^(2).These characteristics make the CsI detectors suitable for monitoring GRBs and other high-energy transients.Initial calibration and performance studies of the CsI detectors'instrumental response were conducted during the early operation phase before2020.In this work,we refine the cross-calibration of CsI detectors using a large sample of 85 bright GRBs.Our analysis reveals that the effective area is inversely proportional to the incident angle(θ),with no correlation observed with the azimuthal angle(θ).We subsequently incorporated this relationship into the calibration database to correct for systematic biases in the initial calibration.Furthermore,we demonstrate that joint spectral analyses incorporating CsI data provide better constraints on highenergy spectral parameters for most GRBs.Additionally,we evaluate,for the first time,the energy response of CsI detectors for pointing observation by measuring the Crab Nebula using the Earth occultation technique.This effort extends the energy range of the Insight-HXMT telescope from 1-250 to 1-750 keV for pointing observations.Those results show that the spectra measured by CsI detectors are consistent with other well-calibrated instruments,validating the reliability and accuracy of the CsI detectors'performance.Our work will contribute to Insight-HXMT's capacity to generate more scientific outputs in the field of time-domain astronomy.展开更多
Objective: ATP6V0d2 is a subunit of the vacuolar-type H+-ATPase (V-ATPase) that pumps H+ ions into lysosomes. TRPML1 (MCOLN1/Mcoln1) transports cations out of lysosomes.Mcoln1^(-/-) mice recapitulate the lysosomal sto...Objective: ATP6V0d2 is a subunit of the vacuolar-type H+-ATPase (V-ATPase) that pumps H+ ions into lysosomes. TRPML1 (MCOLN1/Mcoln1) transports cations out of lysosomes.Mcoln1^(-/-) mice recapitulate the lysosomal storage disorder mucolipidosis type IV (MLIV) phenotype. We previously demonstrated thatMcoln1^(-/-) female mice quickly became infertile at 5 months old (5M) with degenerating corpora lutea (CL) and progesterone (P4) deficiency. We tested our hypothesis thatAtp6v0d2 deficiency could partially compensate forMcoln1 deficiency to restore CL functions inAtp6v0d2^(-/-)Mcoln1^(-/-) mice.Methods: Control andAtp6v0d2^(-/-)Mcoln1^(-/-) female mice underwent fertility test from 2M to 7M. A subset of them was dissected at 5M on day 3.5 post-coitum (D3.5). The D3.5 ovaries from 5M control,Mcoln1^(-/-), andAtp6v0d2^(-/-)Mcoln1^(-/-) mice were evaluated for CL morphology, lipid droplet staining, and markers of mitochondria and P4 steroidogenesis in the luteal cells.Results: The fertility test ofAtp6v0d2^(-/-)Mcoln1^(-/-) female mice (2M–7M) revealed normal mating activity but reduced fertility compared with the control;yet ~25% of them remained fertile at 5M to 7M but with dystocia. We analyzed a subset of 11Atp6v0d2^(-/-)Mcoln1^(-/-) mice (5M) in the fertility test on D3.5: three (27.3%) had normal P4 levels and all examined CL parameters, indicating full restoration of CL function compared withMcoln1^(-/-), whereas eight had P4 deficiency, with two (18.2%) infertile and six (54.5%) once fertile. In contrast toMcoln1^(-/-) CLs, which had extensive amorphous cellular debris, indicating cell degeneration,Atp6v0d2^(-/-)Mcoln1^(-/-) CLs had reduced amorphous cellular debris regardless of P4 levels. However, similar toMcoln1^(-/-) CLs, P4-deficientAtp6v0d2^(-/-)Mcoln1^(-/-) CLs showed impaired differentiation, enlarged lipid droplets, disorganized expression of endothelial basal lamina marker collagen IV, and reduced expression of mitochondrial marker heat shock protein 60 (HSP60) and steroidogenesis rate-limiting protein StAR, indicating that additionalAtp6v0d2 deficiency compensates forMcoln1 deficiency-induced cell degeneration, but is insufficient to restore luteal cell differentiation and P4 steroidogenesis in P4-deficientAtp6v0d2^(-/-)Mcoln1^(-/-) CLs.Conclusion: This study shows thatAtp6v0d2^(-/-)Mcoln1^(-/-) CLs had varied improvements compared withMcoln1^(-/-) CLs, and it providesin vivo genetic evidence of the coordination between different lysosomal channels in CL function.展开更多
In this new era of time-domain and multi-messenger astronomy,various new transients and new phenomena are constantly being discovered thanks to the rapid advances in observations,which provide the excellent opportunit...In this new era of time-domain and multi-messenger astronomy,various new transients and new phenomena are constantly being discovered thanks to the rapid advances in observations,which provide the excellent opportunity to study the physics in the extreme environments.The enhanced X-ray Timing and Polarimetry mission(eXTP),planned to be launched in 2030,has several key advantages,including advanced polarimetry,high sensitivity&large effective area,and wide energy range coverage,which make it a groundbreaking project in high-energy astrophysics.In this article,we briefly introduce the potential time-domain and multi-messenger targets for eXTP,including gravitational-wave(GW)counterparts,gamma-ray bursts(GRBs),magnetars and fast radio bursts(FRBs),tidal disruption events(TDEs),supernovae,high energy neutrinos and TeV active galactic nucleus(AGNs),and so on.We discuss the advantages of future eXTP observations for detecting these sources,their detection capabilities,the abilities to distinguish theoretical models,and their applications in gravity and cosmology.展开更多
In the era of time-domain,multi-messenger astronomy,the detection of transient events on the high-energy electromagnetic sky has become more important than ever.The gravitational wave high-energy electromagnetic count...In the era of time-domain,multi-messenger astronomy,the detection of transient events on the high-energy electromagnetic sky has become more important than ever.The gravitational wave high-energy electromagnetic counterpart all-sky monitor(GECAM)is a dedicated mission to monitor gamma-ray transients,launched in December,2020.A real-time on-board trigger and location software,using the traditional signal-to-noise ratio(SNR)method for blind search,is constrained to relatively bright signals due to the limitations in on-board computing resources and the need for real-time search.In this work,we developed a ground-based pipeline for GECAM to search for various transients,especially for weak bursts missed by on-board software.This pipeline includes both automatic and manual mode,offering options for blind search and targeted search.The targeted search is specifically designed to search for interesting weak bursts,such as gravitational wave-associated gamma-ray bursts(GRBs).From the ground search of the data in the first year,GECAM has been triggered by 54 GRBs and other transients,including soft gamma-ray repeaters,X-ray binaries,solar flares,terrestrial gamma-ray flashes.We report the properties of each type of triggers,such as trigger time and light curves.With this search pipeline and assuming a soft Band spectrum,the GRB detection sensitivity of GECAM is increased to about 1.1×10^(-8)erg cm^(-2)s^(-1)(10-1000 ke V,burst duration of 20 s).These results demonstrate that the GECAM ground search system(both blind search and targeted search)is a versatile pipeline to recover true astrophysical signals which were too weak to be found in the on-board search.展开更多
As China's first X-ray astronomy satellite,the hard X-ray modulation telescope(Insight-HXMT)carries three sets of X-ray telescopes.The high energy X-ray telescope(Insight-HXMT/HE)could serve as an all-sky gamma-ra...As China's first X-ray astronomy satellite,the hard X-ray modulation telescope(Insight-HXMT)carries three sets of X-ray telescopes.The high energy X-ray telescope(Insight-HXMT/HE)could serve as an all-sky gamma-ray monitor with a detection area of up to 5000 cm2and energy range from about 200 ke V to 3 Me V.These characteristics,together with the high orbital inclination angle(43°)of the satellite,make the HE very suitable for detecting terrestrial gamma-ray flashes(TGFs).In this work,we implemented a dedicated TGF search algorithm for Insight-HXMT/HE,and identified 282 bright TGFs in its first four years of operation.We made a systematic study on the properties of these TGFs,including trigger time,duration,intensity,as well as the lightning association.We found that TGFs detected in mid-latitude regions(30°to 43°)are rare and they do not exhibit significantly different properties compared with TGFs in low-latitude(within 30°).Interestingly,the hardness ratio of TGF measured by Insight-HXMT/HE seems to be independent of the TGF duration,which differs from previous studies.These results show that,despite the dedicated design for astronomical observation,Insight-HXMT/HE is a versatile instrument to study energetic radiation phenomena from the Earth.展开更多
Charged particle precipitation typically manifests as a gradual increase and decrease of flux observed by space detectors.Cases with rapid flux variation are very rare,while periodic events are even more extraordinary...Charged particle precipitation typically manifests as a gradual increase and decrease of flux observed by space detectors.Cases with rapid flux variation are very rare,while periodic events are even more extraordinary.These oscillating particle precipitation(OPP)events are usually attributed to the bounce motion of electrons probably induced by lightning.However,the origin of these oscillation events is still on debate.Here we report three peculiar charged particle precipitation events detected by GECAM during a geomagnetic storm on March 21,2024,with two exhibiting significant periodicity.These events were observed around the same region during three consecutive orbits with a life time of more than 3.5 h.Through comprehensive temporal and spectral analyses,we find that one of the OPP events exhibited a transition in spectral lag of mini-pulses,shifting from“softer-earlier”to“softer-later”while showing no significant time evolution in overall frequency characteristics,and that there is no association found between these two OPP events and lightning activity nearby.Finally,we discussed possible scenarios to explain these GECAM-detected OPP events,and we found that they may represent a new type of particle precipitation event or a peculiar lightning-induced electron precipitation(LEP).展开更多
We investigate high time resolution data obtained by the Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)during the flare event on 2022 April 21 at 01:52 UT.Several subpeaks with durat...We investigate high time resolution data obtained by the Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)during the flare event on 2022 April 21 at 01:52 UT.Several subpeaks with durations of 4-6 s have been detected in the hard X-ray precursor phase,and the key feature is that they appear in pairs and seem like double-peak struc-tures.These subpeaks are rarely observed in hard X-ray band and confirmed by the microwave obtained by Nobeyama Radio Polarimeters(NoRP)and Radio Solar Telescope Network(RSTN).While an exponential function can describe the continuum component of the time profile from the precursor to part of the impulsive phase.The periods of quasi-periodic pulsations(QPPs)are detected to be about 7.3 and 12.8 s for the precursor and impulsive phase,respectively,with at least 95%confidence level.The paired QPPs are assumed to be double-peak QPPs and then the scenario of current loop coalescence model is found to be in good agreement with our observation.The precursor phase can be interpreted as the oscillating coalescence of two islands,while the impulsive phase can be interpreted as more islands to coalesce one by one to form larger islands.展开更多
基金This work is supported by the National Institutes of Health(NIH K01ES030014 and P01ES028942)National Science Foundation(NSF 183291)。
文摘The female reproductive system consists of the ovaries,the female gonads,and the reproductive tract organs of the fallopian tubes,uterus,cervix,and vagina.It functions to provide hormonal support and anatomical structure for the production of new offspring.A number of endogenous and exogenous factors can impact female reproductive health and fertility,including genetic vulnerability,medications,environmental exposures,age,nutrition,and diseases.To date,due to the ethical concerns of using human subjects in biomedical research,the majority of studies use in vivo animal models and 2D cell/tissue culture models to study female reproduction.However,the complexity and species difference of the female reproductive system in humans make it difficult to compare to those of animals.Moreover,the monolayered cells cultured on flat plastics or glass lose their 3D architecture as well as the physical and/or biochemical contacts with other cells in vivo.Further,all reproductive organs do not work alone but interconnect with each other and also with non-reproductive organs to support female reproductive,endocrine,and systemic health.These facts suggest that there is an urgent and unmet need to develop representative,effective,and efficient in vitro models for studying human female reproduction.The prodigious advancements of bioengineering(e.g.,biomaterials,3D printing,and organ-on-a-chip)allow us to study female reproduction in an entirely new way.Here,we review recent advances that use bioengineering methods to study female reproduction,including the bioengineering models of the ovary,fallopian tube,uterus,embryo implantation,placenta,and reproductive disease.
基金supported by the National Key R&D Program of China(2021YFA0718500,2022YFF0711404)the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(grant Nos.XDA15360300,XDA15052700 and E02212A02S)+1 种基金the National Natural Science Foundation of China(grant Nos.U2031205,12133007)supported by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences,grant No.XDA15360000。
文摘Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM),consisting of two microsatellites,is designed to detect gamma-ray bursts associated with gravitational-wave events.Here,we introduce the real-time burst alert system of GECAM,with the adoption of the BeiDou-3 short message communication service.We present the post-trigger operations,the detailed ground-based analysis,and the performance of the system.In the first year of the in-flight operation,GECAM was triggered by 42 gamma-ray bursts.The GECAM real-time burst alert system has the ability to distribute the alert within~1 minute after being triggered,which enables timely follow-up observations.
文摘With a high rate of infertility, it is important to understand the context of fertility and family planning in China, to inform the necessity of supportive care. A literature review was undertaken to explore the societal constructs informing perspectives of childbearing, family planning and infertility, alongside Chinese considerations of fertility treatments, including assisted reproductive technologies and fertility counselling. In China, childbearing attitudes and behaviours are shaped by tensions between traditional cultural values of the filial piety originating from Confucianism, the history of strict family planning policy, the recent termination of one-child policy and the socioeconomic circumstance. For infertile Chinese individuals, the inability to meet these childbearing expectations gives rise to significant pressure and consequent psychological distress, particularly depressive symptoms. Demographic factors such as gender, education, income and geographical location have been found to influence prevalence and degree of depression in infertile Chinese men and women. These difficulties are compounded by barriers of cultural acceptance, legislative restrictions and availability of resources for alternative options such as adoption and surrogacy. It is important that these fertility sociocultural factors are taken into consideration when assisting Chinese patients to access and utilise fertility treatment services.
基金performed under the auspices of the Science and Technology Foundation of Guizhou Province(grant No.Qian Ke He Ji Chu ZK[2021]027)Major Science and Technology Program of Xinjiang Uygur Autonomous Region through No.2022A03013-1+1 种基金the National Key Research and Development Program of China(No.2022YFC2205202)the National Natural Science Foundation of China grants 12288102,12041304 and 11847102。
文摘The prompt emission mechanism of gamma-ray bursts(GRBs)is still unclear,and the time-resolved spectral analysis of GRBs is a powerful tool for studying their underlying physical processes.We performed a detailed time-resolved spectral analysis of 78 bright long GRB samples detected by Fermi/Gamma-ray Burst Monitor.A total of 1490 spectra were obtained and their properties were studied using a typical Band-shape model.First,the parameter distributions of the time-resolved spectrum are given as follows:the low-energy spectral indexα~-0.72,high-energy spectral indexβ~2.42,the peak energy E_(p)~221.69 keV,and the energy flux F~7.49×10^(-6)erg cm^(-2)s^(-1).More than 80%of the bursts exhibit the hardest low-energy spectral indexα_(max),exceeding the synchrotron limit(-2/3).Second,the evolution patterns of a and E_(p)were statistically analyzed.The results show that for multi-pulse GRBs the intensity-tracking pattern is more common than the hard-to-soft pattern in the evolution of both E_(p)andα.The hard-to-soft pattern is generally shown in single-pulse GRBs or in the initial pulse of multi-pulse GRBs.Finally,we found a significant positive correlation between F and E_(p),with half of the samples exhibiting a positive correlation between F andα.We discussed the spectral evolution of different radiation models.The diversity of spectral evolution patterns indicates that there may be more than one radiation mechanism occurring in the GRB radiation process,including photo spheric radiation and synchrotron radiation.However,it may also involve only one radiation mechanism,but more complicated physical details need to be considered.
基金the HXMT mission,a project funded by China National Space Administration(CNSA)and the Chinese Academy of Sciences(CAS)supported by the National Key R&D Program of China(2016YFA0400800)the National Natural Science Foundation of China(Grant Nos.11673023,U1838201,U1838115,U1838111,U1838202,11733009 and U1838108)。
文摘We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846-031 during its outburst in 2019 with the observations of Insight-HXMT,NICER and MAXI.This outburst can be classified roughly into four different states.Type-C quasi-periodic oscillations(QPOs)observed by NICER(about 0.1-6 Hz)and Insight-HXMT(about 0.7-8 Hz)are also reported in this work.Meanwhile,we study various physical quantities related to QPO frequency.The QPO rms-frequency relationship in the energy band 1-10 keV indicates that there is a turning pointing in frequency around2 Hz,which is similar to that of GRS 1915+105.A possible hypothesis for the relationship above may be related to the inclination of the source,which may require a high inclination to explain it.The relationships between QPO frequency and QPO rms,hardness,total fractional rms and count rate have also been found in other transient sources,which can indicate that the origin of type-C QPOs is non-thermal.
基金supported by the National Key R&D Program of China(No.2022YFE0133700)the National Natural Science Foundation of China(NSFC,grant Nos.12273008,11963003,12273007 and 62062025)+4 种基金the National SKA Program of China(No.2020SKA0110300)the Guizhou Province Science and Technology Support Program(General Project)No.Qianhe Support[2023]General 333,Science and Technology Foundation of Guizhou Province(Key Program,No.[2019]1432)the Guizhou Provincial Science and Technology Projects(Nos.ZK[2022]143 and ZK[2022]304)the Cultivation project of Guizhou University(No.[2020]76)。
文摘Pulsar search is always the basis of pulsar navigation,gravitational wave detection and other research topics.Currently,the volume of pulsar candidates collected by the Five-hundred-meter Aperture Spherical radio Telescope(FAST)shows an explosive growth rate that has brought challenges for its pulsar candidate filtering system.Particularly,the multi-view heterogeneous data and class imbalance between true pulsars and non-pulsar candidates have negative effects on traditional single-modal supervised classification methods.In this study,a multi-modal and semi-supervised learning based on a pulsar candidate sifting algorithm is presented,which adopts a hybrid ensemble clustering scheme of density-based and partition-based methods combined with a feature-level fusion strategy for input data and a data partition strategy for parallelization.Experiments on both High Time Resolution Universe SurveyⅡ(HTRU2)and actual FAST observation data demonstrate that the proposed algorithm could excellently identify pulsars:On HTRU2,the precision and recall rates of its parallel mode reach0.981 and 0.988 respectively.On FAST data,those of its parallel mode reach 0.891 and 0.961,meanwhile,the running time also significantly decreases with the increment of parallel nodes within limits.Thus,we can conclude that our algorithm could be a feasible idea for large scale pulsar candidate sifting for FAST drift scan observation.
基金supported by the National Key R&D Program of China(2021YFA0718500)support from the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(grant Nos.XDA15360102,XDA15360300,XDA15052700 and E02212A02S)+1 种基金the National Natural Science Foundation of China(grant Nos.12173038 and U2038106)the National HEP Data Center(grant No.E029S2S1)。
文摘Fast and reliable localization of high-energy transients is crucial for characterizing the burst properties and guiding the follow-up observations.Localization based on the relative counts of different detectors has been widely used for all-sky gamma-ray monitors.There are two major methods for this count distribution localization:χ^(2)minimization method and the Bayesian method.Here we propose a modified Bayesian method that could take advantage of both the accuracy of the Bayesian method and the simplicity of the χ^(2)method.With comprehensive simulations,we find that our Bayesian method with Poisson likelihood is generally more applicable for various bursts than the χ^(2)method,especially for weak bursts.We further proposed a location-spectrum iteration approach based on the Bayesian inference,which could alleviate the problems caused by the spectral difference between the burst and location templates.Our method is very suitable for scenarios with limited computation resources or timesensitive applications,such as in-flight localization software,and low-latency localization for rapidly follow-up observations.
基金supported by the Strategic Priority Research Program on Space Science of the Chinese Academy of Sciences,the support from the Strategic Priority Research Program on Space Science(grant Nos.XDA15360300,XDA15360000,XDA15360102,XDA15052700 and E02212A02S)of the Chinese Academy of Sciencesthe National Natural Science Foundation of China(NSFC,Grant No.12173038)and BeiDou navigation system。
文摘Realtime trigger and localization of bursts are the key functions of GECAM,an all-sky gamma-ray monitor launched on 2020 December 10.We developed a multifunctional trigger and localization software operating in the CPU of the GECAM Electronic Box.This onboard software has the following features:high trigger efficiency for real celestial bursts with a suppression of false triggers caused by charged particle bursts and background fluctuation,dedicated localization algorithm optimized for both short and long bursts,and low time latency of the trigger information which is downlinked through the Global Short Message Communication service of the global BeiDou navigation system.This paper provides a detailed description of the design and development of the trigger and localization software system for GECAM.It covers the general design,workflow,the main functions,and the algorithms used in the system.The paper also includes on-ground trigger tests using simulated gamma-ray bursts generated by a dedicated X-ray tube,as well as an overview of the performance for real celestial bursts during its in-orbit operation.
基金supported by the National SKA Program of China(Nos.2022SKA0130100,2020SKA0120100 and 2022SKA0130104)Guizhou Province Science and Technology Foundation(No.ZK[2022]304)+9 种基金the Major Science and Technology Program of Xinjiang Uygur Autonomous Region(Nos.2022A03013-2 and 2022A03013-4)the Scientific Research Project of the Guizhou Provincial Education(Nos.KY[2022]132,KY[2022]123 and KY[2022]137)the National Natural Science Foundation of China(Nos.11873080,U1731238,11565010,12103013,U1838109,U1831120,12273008 and 12103013)the Joint Research Fund in Astronomy under cooperative agreement between the National Natural Science Foundation of China and Chinese Academy of Sciences(No.U1931101)the Foundation of Guizhou Provincial Education Department(Nos.KY(2020)003 and KY(2021)303)the Guizhou Province Science and Technology Support Program(No.[2023]General 333)the 2021 project Xinjiang Uygur autonomous region of China for Tianshan elites,the Key Laboratory of Xinjiang Uygur Autonomous Region No.2020D04049the Academic New Seeding Fund Project of Guizhou Normal University(No.[2022]B18)the CAS Jianzhihua projectThe Parkes radio telescope is part of the Australia Telescope National Facility which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO。
文摘In this paper,we presented the 23.3 yr of pulsar timing results of PSR J1456-6413 based on the observations of Parkes 64 m radio telescope.We detected two new glitches at MJD 57093(3)and 59060(12)and confirmed its first glitch at MJD 54554(10).The relative sizes(Δν/ν)of these two new glitches are 0.9×10^(-9)and 1.16×10^(-9),respectively.Using the“Cholesky”timing analysis method,we have determined its position,proper motion,and two-dimensional transverse velocities from the data segments before and after the second glitch,respectively.Furthermore,we detected exponential recovery behavior after the first glitch,with a recovery timescale of approximately 200 days and a corresponding exponential recovery factor Q of approximately 0.15(2),while no exponential recovery was detected for the other two glitches.More interestingly,we found that the leading component of the integral pulse profile after the second glitch became stronger,while the main component became weaker.Our results will expand the sample of pulsars with magnetosphere fluctuation triggered by the glitch event.
基金supported by the National Key R&D Program of China(2022YFF0711404,2021YFA0718500)International Partnership Program of Chinese Academy of Sciences(grant No.113111KYSB20190020)+2 种基金the National Natural Science Foundation of China(NSFC,Grant No.U1938106)the open subject of the National HEP Data Center(E029S2S1)support from the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(grant Nos.XDA15360102,XDA15360300,XDA15052700 and E02212A02S)。
文摘The Gravitational wave burst high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)is a dedicated mission for monitoring high-energy transients.Here we report the design of the GECAM Scientific Ground Segment(GSGS)in terms of the scientific requirements,including the architecture,the external interfaces,the main function,and workflow.Judging from the analysis and verification results during the commissioning phase,the GSGS functions well and is able to monitor the status of the payloads,adjust the parameters,develop the scientific observation plans,generate the scientific data products,analyze the data,etc.Thus,the on-orbit operation and scientific researches of GECAM are guaranteed.
基金supported by the Strategic Priority Program on Space Science,the Chinese Academy of Sciences,grant Nos.XDA15360102,XDA15360300 and E02212A02Sthe National Natural Science Foundation of China(Project:12061131007)。
文摘The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)mission is designed to monitor the Gamma-Ray Bursts(GRBs)associated with gravitational waves and other high-energy transient sources.The mission consists of two microsatellites which are planned to operate at the opposite sides of the Earth.Each GECAM satellite could detect and localize GRBs in about 8 keV-5 MeV with its 25 Gamma-Ray Detectors(GRDs).In this work,we report the in-flight energy calibration of GRDs using the characteristic gamma-ray lines in the background spectra,and show their performance evolution during the commissioning phase.Besides,a preliminary cross-calibration of energy response with Fermi GBM data is also presented,validating the energy response of GRDs.
基金supported by the National SKA Program of China (Grant Nos. 2020SKA0120100 and 2020SKA0120200)the National Natural Science Foundation of China (Grant Nos. 12041304, 11873067, 11988101, 12041303, 11725313, 11725314, 11833003, 12003028, 12041306, 12103089, U2031209, U2038105, and U1831207)+8 种基金the National Key Research and Development Program of China (Grant Nos. 2019YFA0405100, 2017YFA0402602, 2018YFA0404204, and 2016YFA0400801)Key Research Program of the Chinese Academy of Sciences (Grant No. QYZDJ-SSW-SLH021)Natural Science Foundation of Jiangsu Province (Grant No. BK20211000)Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CAS, the Strategic Priority Research Program on Space Science, the Western Light Youth Project of Chinese Academy of Sciences (Grant Nos. XDA15360000, XDA15052700, and XDB23040400)funding from the MaxPlanck Partner Group, the science research grants from the China Manned Space Project (Grant Nos. CMS-CSST2021-B11 and CMS-CSST-2021-A11)PKU development (Grant No. 7101502590)support from the XPLORER PRIZEsupported by Fundamental Research Funds for the Central Universities (Grant No. 14380046)the Program for Innovative Talents, Entrepreneur in Jiangsu。
文摘Fast radio bursts(FRBs) are highly dispersed millisecond-duration radio bursts,[1,2]of which the physical origin is still not fully understood. FRB 20201124A is one of the most actively repeating FRBs. In this paper, we present the collection of 1863 burst dynamic spectra of FRB 20201124A measured with the Five-hundred-meter Aperture Spherical radio Telescope(FAST). The current collection, taken from the observation during the FRB active phase from April to June 2021, is the largest burst sample detected for any FRB so far. The standard PSRFITs format is adopted, including dynamic spectra of the burst, and the time information of the dynamic spectra, in addition, mask files help readers to identify the pulse positions are also provided. The dataset is available in Science Data Bank, with the link https://www.doi.org/10.57760/sciencedb.j00113.00076.
文摘[Objectives] This study was conducted to explore the effects of different N application rates and densities on the growth and development of direct-seeding rape as well as on its yield.[Methods] A field experiment was carried out by setting five N fertilizer treatments and three density levels.[Results] Increasing seeding density and N application rate could improve the seed yield of rape. The suitable N application rate for the three densities were calculated using the fitted fertilizer efficiency models, respectively, to be 186.77, 221.35 and 236.14 kg/hm^2, at which the yields were the highest. The results showed that in this area, the seeding density of direct-seeding rape could be selected in the range of 6.0×10^5-7.5×10^5 plants/hm^2, and the suitable N application rate could be in the range of 221.35-236.14 kg/hm^2.[Conclusions] This study provides a theoretical basis for the maximization of spatial resource and efficient utilization of fertilizer.
基金the support from the National Key Research and Development Program of China(Grant No.2021YFA0718500)the Strategic Priority Research Program+1 种基金the Chinese Academy of Sciences(Grant Nos.XDB0550300 and XDA30050000)the National Natural Science Foundation of China(Grant Nos.12273042,12494572,12373047,12273043,and 12103055)。
文摘As one of three primary scientific payloads of Insight-Hard X-ray Modulation Telescope(Insight-HXMT),the High Energy Xray telescope(HE)consists of 18 Nal/CsI phoswich detectors,and the CsI detectors can detect gamma-rays that penetrate the satellite from all directions,with an energy range of about 60 keV to 3.2 MeV and a total geometric area of about 5100 cm^(2).These characteristics make the CsI detectors suitable for monitoring GRBs and other high-energy transients.Initial calibration and performance studies of the CsI detectors'instrumental response were conducted during the early operation phase before2020.In this work,we refine the cross-calibration of CsI detectors using a large sample of 85 bright GRBs.Our analysis reveals that the effective area is inversely proportional to the incident angle(θ),with no correlation observed with the azimuthal angle(θ).We subsequently incorporated this relationship into the calibration database to correct for systematic biases in the initial calibration.Furthermore,we demonstrate that joint spectral analyses incorporating CsI data provide better constraints on highenergy spectral parameters for most GRBs.Additionally,we evaluate,for the first time,the energy response of CsI detectors for pointing observation by measuring the Crab Nebula using the Earth occultation technique.This effort extends the energy range of the Insight-HXMT telescope from 1-250 to 1-750 keV for pointing observations.Those results show that the spectra measured by CsI detectors are consistent with other well-calibrated instruments,validating the reliability and accuracy of the CsI detectors'performance.Our work will contribute to Insight-HXMT's capacity to generate more scientific outputs in the field of time-domain astronomy.
基金funded by NIH R01HD065939(co-funded by ORWH and NICHD)NIH R03HD097384NIH R03 HD100652 to X.Y.
文摘Objective: ATP6V0d2 is a subunit of the vacuolar-type H+-ATPase (V-ATPase) that pumps H+ ions into lysosomes. TRPML1 (MCOLN1/Mcoln1) transports cations out of lysosomes.Mcoln1^(-/-) mice recapitulate the lysosomal storage disorder mucolipidosis type IV (MLIV) phenotype. We previously demonstrated thatMcoln1^(-/-) female mice quickly became infertile at 5 months old (5M) with degenerating corpora lutea (CL) and progesterone (P4) deficiency. We tested our hypothesis thatAtp6v0d2 deficiency could partially compensate forMcoln1 deficiency to restore CL functions inAtp6v0d2^(-/-)Mcoln1^(-/-) mice.Methods: Control andAtp6v0d2^(-/-)Mcoln1^(-/-) female mice underwent fertility test from 2M to 7M. A subset of them was dissected at 5M on day 3.5 post-coitum (D3.5). The D3.5 ovaries from 5M control,Mcoln1^(-/-), andAtp6v0d2^(-/-)Mcoln1^(-/-) mice were evaluated for CL morphology, lipid droplet staining, and markers of mitochondria and P4 steroidogenesis in the luteal cells.Results: The fertility test ofAtp6v0d2^(-/-)Mcoln1^(-/-) female mice (2M–7M) revealed normal mating activity but reduced fertility compared with the control;yet ~25% of them remained fertile at 5M to 7M but with dystocia. We analyzed a subset of 11Atp6v0d2^(-/-)Mcoln1^(-/-) mice (5M) in the fertility test on D3.5: three (27.3%) had normal P4 levels and all examined CL parameters, indicating full restoration of CL function compared withMcoln1^(-/-), whereas eight had P4 deficiency, with two (18.2%) infertile and six (54.5%) once fertile. In contrast toMcoln1^(-/-) CLs, which had extensive amorphous cellular debris, indicating cell degeneration,Atp6v0d2^(-/-)Mcoln1^(-/-) CLs had reduced amorphous cellular debris regardless of P4 levels. However, similar toMcoln1^(-/-) CLs, P4-deficientAtp6v0d2^(-/-)Mcoln1^(-/-) CLs showed impaired differentiation, enlarged lipid droplets, disorganized expression of endothelial basal lamina marker collagen IV, and reduced expression of mitochondrial marker heat shock protein 60 (HSP60) and steroidogenesis rate-limiting protein StAR, indicating that additionalAtp6v0d2 deficiency compensates forMcoln1 deficiency-induced cell degeneration, but is insufficient to restore luteal cell differentiation and P4 steroidogenesis in P4-deficientAtp6v0d2^(-/-)Mcoln1^(-/-) CLs.Conclusion: This study shows thatAtp6v0d2^(-/-)Mcoln1^(-/-) CLs had varied improvements compared withMcoln1^(-/-) CLs, and it providesin vivo genetic evidence of the coordination between different lysosomal channels in CL function.
基金supported by China’s Space Origins Exploration Programsupport from the Chinese Academy of Sciences (Grant No.E32983U810)+13 种基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDB0550300)the National Natural Science Foundation of China (Grant No.12325301)supported by the National Natural Science Foundation of China (Grant Nos.12233002,and 12041306)the National SKA Program of China (Grant No.2020SKA0120300)the National Key R&D Program of China (Grant No.2021YFA0718500)the support from the Xinjiang Tianchi Programsupported by the National Natural Science Foundation of China (Grant No.12333007)the International Partnership Program of the Chinese Academy of Sciences (Grant No.113111KYSB20190020)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDA15020100)supported by the Beijing Municipal Natural Science Foundation (Grant No.1242032)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No.2022056)supported by the National Key Research and Development Program of China (Grant Nos.2022YFC2205201,and 2020YFC2201400)funding by the European Union-Next Generation EU RFF M4C2 1.1 PRIN 2022 project “2022RJLWHN URKA”INAF 2023 Theory Grant Ob Fu 1.05.23.06.06 “Understanding R-process & Kilonovae Aspects (URKA)”.
文摘In this new era of time-domain and multi-messenger astronomy,various new transients and new phenomena are constantly being discovered thanks to the rapid advances in observations,which provide the excellent opportunity to study the physics in the extreme environments.The enhanced X-ray Timing and Polarimetry mission(eXTP),planned to be launched in 2030,has several key advantages,including advanced polarimetry,high sensitivity&large effective area,and wide energy range coverage,which make it a groundbreaking project in high-energy astrophysics.In this article,we briefly introduce the potential time-domain and multi-messenger targets for eXTP,including gravitational-wave(GW)counterparts,gamma-ray bursts(GRBs),magnetars and fast radio bursts(FRBs),tidal disruption events(TDEs),supernovae,high energy neutrinos and TeV active galactic nucleus(AGNs),and so on.We discuss the advantages of future eXTP observations for detecting these sources,their detection capabilities,the abilities to distinguish theoretical models,and their applications in gravity and cosmology.
基金supported by the National Natural Science Foundation of China(Grant Nos.12303045,12273042,and 12373047)the National Key R&D Program of China(Grant No.2022YFF0711404)+3 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDA15360102,XDA15360300,and XDA15052700)The GECAM(Huairou-1)mission was supported by the Strategic Priority Research Program on Space Science(Grant No.XDA15360000)of the Chinese Academy of Sciencesthe support from the Natural Science Foundation of Hebei Province(Grant No.A2023205020)the Science Foundation of Hebei Normal University(Grant No.L2023B11)。
文摘In the era of time-domain,multi-messenger astronomy,the detection of transient events on the high-energy electromagnetic sky has become more important than ever.The gravitational wave high-energy electromagnetic counterpart all-sky monitor(GECAM)is a dedicated mission to monitor gamma-ray transients,launched in December,2020.A real-time on-board trigger and location software,using the traditional signal-to-noise ratio(SNR)method for blind search,is constrained to relatively bright signals due to the limitations in on-board computing resources and the need for real-time search.In this work,we developed a ground-based pipeline for GECAM to search for various transients,especially for weak bursts missed by on-board software.This pipeline includes both automatic and manual mode,offering options for blind search and targeted search.The targeted search is specifically designed to search for interesting weak bursts,such as gravitational wave-associated gamma-ray bursts(GRBs).From the ground search of the data in the first year,GECAM has been triggered by 54 GRBs and other transients,including soft gamma-ray repeaters,X-ray binaries,solar flares,terrestrial gamma-ray flashes.We report the properties of each type of triggers,such as trigger time and light curves.With this search pipeline and assuming a soft Band spectrum,the GRB detection sensitivity of GECAM is increased to about 1.1×10^(-8)erg cm^(-2)s^(-1)(10-1000 ke V,burst duration of 20 s).These results demonstrate that the GECAM ground search system(both blind search and targeted search)is a versatile pipeline to recover true astrophysical signals which were too weak to be found in the on-board search.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFA0718500)the National Natural Science Foundation of China(Grant No.12273042)the Science Research Program of Dezhou University(2024xjrc142)。
文摘As China's first X-ray astronomy satellite,the hard X-ray modulation telescope(Insight-HXMT)carries three sets of X-ray telescopes.The high energy X-ray telescope(Insight-HXMT/HE)could serve as an all-sky gamma-ray monitor with a detection area of up to 5000 cm2and energy range from about 200 ke V to 3 Me V.These characteristics,together with the high orbital inclination angle(43°)of the satellite,make the HE very suitable for detecting terrestrial gamma-ray flashes(TGFs).In this work,we implemented a dedicated TGF search algorithm for Insight-HXMT/HE,and identified 282 bright TGFs in its first four years of operation.We made a systematic study on the properties of these TGFs,including trigger time,duration,intensity,as well as the lightning association.We found that TGFs detected in mid-latitude regions(30°to 43°)are rare and they do not exhibit significantly different properties compared with TGFs in low-latitude(within 30°).Interestingly,the hardness ratio of TGF measured by Insight-HXMT/HE seems to be independent of the TGF duration,which differs from previous studies.These results show that,despite the dedicated design for astronomical observation,Insight-HXMT/HE is a versatile instrument to study energetic radiation phenomena from the Earth.
基金supported by the National Natural Science Foundation of China(Grant Nos.12273042,and 12303045)the National Key R&D Program of China(Grant No.2021YFA0718500)+2 种基金the Natural Science Foundation of Hebei Province(Grant No.A2023205020)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB0550300,and XDA30050000)The GECAM(Huairou-1)mission is supported by the Strategic Priority Research Program on Space Science of the Chinese Academy of Sciences(Grant No.XDA15360000).We thank the World Wide Lightning Location Network(http://wwlln.net)as a collaboration of more than 50 universities.Chenwei Wang appreciates Wen Cheng,Yixin Sun,and Lu Wang for helpful discussions.
文摘Charged particle precipitation typically manifests as a gradual increase and decrease of flux observed by space detectors.Cases with rapid flux variation are very rare,while periodic events are even more extraordinary.These oscillating particle precipitation(OPP)events are usually attributed to the bounce motion of electrons probably induced by lightning.However,the origin of these oscillation events is still on debate.Here we report three peculiar charged particle precipitation events detected by GECAM during a geomagnetic storm on March 21,2024,with two exhibiting significant periodicity.These events were observed around the same region during three consecutive orbits with a life time of more than 3.5 h.Through comprehensive temporal and spectral analyses,we find that one of the OPP events exhibited a transition in spectral lag of mini-pulses,shifting from“softer-earlier”to“softer-later”while showing no significant time evolution in overall frequency characteristics,and that there is no association found between these two OPP events and lightning activity nearby.Finally,we discussed possible scenarios to explain these GECAM-detected OPP events,and we found that they may represent a new type of particle precipitation event or a peculiar lightning-induced electron precipitation(LEP).
基金supported by the National Natural Science Foundation of China (Grant Nos. U1938102, and 11973092)the National Program on Key Research and Development Project (Grant No. 2016YFA0400802)supported by the Surface Project of Jiangsu Province (Grant No. BK20211402)
文摘We investigate high time resolution data obtained by the Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)during the flare event on 2022 April 21 at 01:52 UT.Several subpeaks with durations of 4-6 s have been detected in the hard X-ray precursor phase,and the key feature is that they appear in pairs and seem like double-peak struc-tures.These subpeaks are rarely observed in hard X-ray band and confirmed by the microwave obtained by Nobeyama Radio Polarimeters(NoRP)and Radio Solar Telescope Network(RSTN).While an exponential function can describe the continuum component of the time profile from the precursor to part of the impulsive phase.The periods of quasi-periodic pulsations(QPPs)are detected to be about 7.3 and 12.8 s for the precursor and impulsive phase,respectively,with at least 95%confidence level.The paired QPPs are assumed to be double-peak QPPs and then the scenario of current loop coalescence model is found to be in good agreement with our observation.The precursor phase can be interpreted as the oscillating coalescence of two islands,while the impulsive phase can be interpreted as more islands to coalesce one by one to form larger islands.
