The Radiation Structure of PSR B2016++28 Observed with FAST

With the largest dish Five-hundred-meter Aperture Spherical radio Telescope (FAST), both the mean and single pulses of PSR B2016$+$28, especially including the single-pulse structure, are investigated in detail in this study. The mean pulse profiles at different frequencies can be well fitted in a conal model, and the peak separation of intensity-dependent pulse profiles increases with intensity. The integrated pulses are obviously frequency dependent (pulse width decreases by $\sim\,20\%$ as frequency increases from 300 MHz to 750 MHz), but the structure of single pulses changes slightly (the corresponding correlation scale decreases by only $\sim\,1\%$). This disparity between mean and single pulses provides independent evidence for the existence of the RS-type vacuum inner gap, indicating a strong bond between particles on the pulsar surface. Diffused drifting sub-pulses are analyzed. The results show that the modulation period along pulse series ($P_3$) is positively correlated to the separation between two adjacent sub-pulses ($P_2$). This correlation may hint a rough surface on the pulsar, eventually resulting in the irregular drift of sparks. All the observational results may have significant implications in the dynamics of pulsar magnetosphere and are discussed extensively in this paper.Comment: Sci. China-Phys. Mech. Astron. 62, 959505 (2019

Study of Three Rotating Radio Transients with FAST

Rotating radio transients (RRATs) are peculiar astronomical objects whose emission mechanism remains under investigation. In this paper, we present observations of three RRATs, J1538+2345, J1854+0306 and J1913+1330, observed with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Specifically, we analyze the mean pulse profiles and temporal flux density evolutions of the RRATs. Owing to the high sensitivity of FAST, the derived burst rates of the three RRATs are higher than those in previous reports. RRAT J1854+0306 exhibited a time-dynamic mean pulse profile, whereas RRAT J1913+1330 showed distinct radiation and nulling segments on its pulse intensity trains. The mean pulse profile variation with frequency is also studied for RRAT J1538+2345 and RRAT J1913+1330, and the profiles at different frequencies could be well fitted with a cone-core model and a conal-beam model, respectively.Comment: Sci. China-Phys. Mech. Astron. 62, 959503 (2019

The FAST discovery of an Eclipsing Binary Millisecond Pulsar in the Globular Cluster M92 (NGC 6341)

We report the discovery of an eclipsing binary millisecond pulsar in the globular cluster M92 (NGC6341) with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). PSR J1717+4308A, or M92A, has a pulse frequency of 316.5~Hz (3.16~ms) and a dispersion measure of 35.45 pc cm$^{-3}$. The pulsar is a member of a binary system with an orbital period of 0.20~days around a low-mass companion which has a median mass of $\sim$0.18~\Ms. From observations so far, at least two eclipsing events have been observed in each orbit. The longer one lasted for ~5000~s in the orbital phase range 0.1--0.5. The other lasted for ~500~s and occurred between 1000--2000~s before or after the longer eclipsing event. The lengths of these two eclipsing events also change. These properties suggest that J1717+4308A is a ``red-back'' system with a low-mass main sequence or sub-giant companion. Timing observations of the pulsar and further searches of the data for additional pulsars are ongoing.Comment: 9 pages, 2 figures, submitted to ApJL, comments are welcomed

ALDH1 Expression and Vasculogenic Mimicry Are Positively Associated with Poor Prognosis in Patients with Breast Cancer

Background/Aims: This study aimed to explore the prognostic value of aldehyde dehydrogenase 1 (ALDH1) expression and vasculogenic mimicry (VM) in patients with breast cancer. Methods: ALDH1 expression and the presence of VM were examined by immunohistochemistry and CD31/PAS double staining, respectively, using formalin-fixed paraffin-embedded tissues from 202 breast cancer patients. The mean follow-up period ranged from 15 to 115 months. The Kaplan-Meier method was used to plot survival curves. Prognostic values were assessed by multivariate analysis using the Cox regression model. Results: ALDH1 expression was strongly associated with VM (P = 0.005). ALDH1 expression was positively correlated with histological grade (P = 0.011). Both ALDH1 expression and VM were negatively related to the status of the estrogen receptor and progesterone receptor and were statistically increased in triple-negative breast cancer. Patients with ALDH1 expression or VM displayed poorer disease-free survival (DFS) and overall survival (OS) than ALDH1-negative or VM-negative patients, with the worst OS and DFS observed in ALDH1/VM-double-positive patients. ALDH1-positive and VM-positive were independent survival risk factors for DFS and OS. Conclusion: ALDH1 expression and VM are correlated with the survival rate of patients with breast cancer. ALDH1 and VM, either alone or together, are prognostic factors in patients with breast cancer

Metadata Management For Distributed Multimedia Storage System

As a result of the multimedia rapid growth, there has been a huge increase in the amount of information generated and shared by people all over the world. Demand for large-scale multimedia storage system is growing rapidly. This paper describes the design and implementation of the Two-level metadata server for Distributed Multimedia Storage System (DMSS). The DMSS divides the logical view of the stored data from the physical view. The logical view is managed by the metadata server which is called GMS (Global Metadata Server), and the physical view is managed by a component of storage servers which is called LMS (Local Metadata Server). Adopting LMS, each storage server can maintain its own storage resources and metadata and data independently, and can offer storage service independently. The DMSS allows the application servers to access the storage servers directly and in parallel providing very high performance. © 2008 IEEE

The Research And Design For High Availability Object Storage System

With the growing scale of the computer storage systems, the likelihood of multi-disk failures happening in the storage systems has increased dramatically. Based on a thorough analysis on the fault-tolerance capability on various existing storage systems, we propose a new hierarchical, highly reliable, multi-disk fault-tolerant storage system architecture: High Availability Object Storage System (HAOSS). In the HAOSS, each object has an attribute field for reliability level, which can be set by the user according to the importance of data. Higher reliability level corresponds to better data survivability in case of multi-device failure. The HAOSS is composed of two layers: the upper-layer and the lower-layer. The upper-layer achieves the high availability by storing multiple replicas for each storage object in a set of storage devices. The individual replicas can service the I/O requests in parallel so as to obtain high performance. The lower-layer deploys RAID5, RAID6 or RAID-Blaum coding schemes to tolerate multi-disk failures. In addition, the disk utilization rate of RAID-Blaum is higher than that of multiple replicas, and it can be further improved by growing the RAID group size. These advantages come at the price of more complicated fault-tolerant coding schemes, which involve a large amount of calculation for encoding and cause an adverse impact on the I/O performance, especially on the write performance. Results from both our internal experiments and third-party independent tests have shown that HAOSS servers have better multi-disk- failure tolerance than existing similar products. In a 1000Mb Ethernet interconnection environment, with a request block size of 1024KB, the sequential read performance for a HAOSS server reaches 104MB/s, which is very close to the theoretical maximum effective bandwidth of Ethernet networks. The HAOSS offers a complete storage solution for high availability applications without the compromises that today\u27s storage systems require in either performance or fault-tolerance. © 2009 SPIE

Seasonal variation of microcystins and their accumulation in fish in two large shallow lakes of China

Bioaccumulation of microcystins (MCs) has been widely observed in aquatic vertebrates and invertebrates, but its seasonal and specific variations remain unclear. In the present study, dissolved MCs in water, algal cell-bound MCs and muscle tissue MCs of nine fish species were investigated monthly in two of the largest shallow lakes in China: Lake Taihu and Lake Chaohu. The fish species were grouped as carnivorous, planktivorous, and omnivorous fish. Seasonal variations in dissolved and algal cell-bound MCs in water and MCs contents of fish hepatopancreas and muscle were investigated in the two lakes from 2009 to 2010. Dissolved MCs in water ranged from 0.35 to 2.56 mu g l(-1) in Lake Taihu and 0.16 to 2.45 mu g l(-1) in Lake Chaohu, and showed seasonally a unimodal distribution. Algal cell-bound MCs also showed a similar seasonal variation in both lakes, but dissolved MCs in water peaked about one month later than algal cell-bound MCs. The MCs content in the Fish muscle was higher MCs from October to December than in the other months. For most of the fish species, it exceeded the tolerable daily intake value established by the WHO. The averaged MCs content in the muscle of carnivorous, planktivorous, omnivorous fish was 48.2, 28.7 and 37.8 mu g kg(-1) in Lake Taihu, respectively, and 27.8, 18.6 and 20.4 mu g kg(-1) in Lake Chaohu. It was significantly higher in carnivorous fish than in planktivorous and omnivorous fish, indicating that carnivorous fish has a higher exposure risk to the local people when consuming the harvested fish. The average ratio of hepatopancreas to muscle MCs contents was 13.0, 25.2, 13.8 for carnivorous, planktivorous, omnivorous fishes in Lake Taihu, respectively, and 18.0, 24.9, 14.8 in Lake Chaohu. These ratio for planktivorous fish almost doubled that for carnivorous and omnivorous fish. High correlation of MC content in carnivorous, omnivorous and planktivorous fish indicates that MCs can be delivered along trophic levels in the food chains