922 research outputs found
Polynomial extensions of semistar operations
We provide a complete solution to the problem of extending arbitrary semistar
operations of an integral domain to semistar operations of the polynomial
ring . As an application, we show that one can reobtain the main results
of some previous papers concerning the problem in the special cases of stable
semistar operations of finite type or semistar operations defined by families
of overrings. Finally, we investigate the behavior of the polynomial extensions
of the most important and classical operations such as , , ,
and operations
A Robust Fault-Tolerant and Scalable Cluster-wide Deduplication for Shared-Nothing Storage Systems
Deduplication has been largely employed in distributed storage systems to
improve space efficiency. Traditional deduplication research ignores the design
specifications of shared-nothing distributed storage systems such as no central
metadata bottleneck, scalability, and storage rebalancing. Further,
deduplication introduces transactional changes, which are prone to errors in
the event of a system failure, resulting in inconsistencies in data and
deduplication metadata. In this paper, we propose a robust, fault-tolerant and
scalable cluster-wide deduplication that can eliminate duplicate copies across
the cluster. We design a distributed deduplication metadata shard which
guarantees performance scalability while preserving the design constraints of
shared- nothing storage systems. The placement of chunks and deduplication
metadata is made cluster-wide based on the content fingerprint of chunks. To
ensure transactional consistency and garbage identification, we employ a
flag-based asynchronous consistency mechanism. We implement the proposed
deduplication on Ceph. The evaluation shows high disk-space savings with
minimal performance degradation as well as high robustness in the event of
sudden server failure.Comment: 6 Pages including reference
Estimating the probability of stroke in Korean hypertensive patients visiting tertiary hospitals using a risk profile from the framingham study
<p>Abstract</p> <p>Background</p> <p>Hypertension is the most important single modifiable risk factor for stroke. We investigated the distribution of stroke risk factors and 10-year probability of stroke in Korean hypertensive patients.</p> <p>Methods</p> <p>A total of 1,402 hypertensive patients treated by cardiology departments at 37 general hospitals nationwide were enrolled. Risk factors for stroke were evaluated using a series of laboratory tests and physical examinations, and the 10-year probability of stroke was determined by applying the Framingham stroke risk equation.</p> <p>Results</p> <p>The proportion of patients who have uncontrolled hypertension despite use of antihypertensives was 37.2% (37.2% women, 37.3% men, p = 0.990). The average 10-year probability of stroke in hypertensive patients was 24.27% (24.17% women, 24.39% men, p = 0.825), approximately 2.4 times higher than of the risk of stroke observed in the Korean Cancer Prevention Study [KCPS] cohort. The 10-year stroke probability in patients with hypertension increased in proportion to age. In patients for hypertension, the 10-year probability of stroke increased in proportion to blood pressure.</p> <p>Conclusion</p> <p>Aggressive interventions are mandated to reduce blood pressure and alleviate the high risk of stroke in hypertensive patients.</p
Characterization of the Lytic Bacteriophage phiEaP-8 Effective against Both Erwinia amylovora and Erwinia pyrifoliae Causing Severe Diseases in Apple and Pear
Bacteriophages, bacteria-infecting viruses, have been recently reconsidered as a biological control tool for preventing bacterial pathogens. Erwinia amylovora and E. pyrifoliae cause fire blight and black shoot blight disease in apple and pear, respectively. In this study, the bacteriophage phiEaP-8 was isolated from apple orchard soil and could efficiently and specifically kill both E amylovora and E. pyrifoliae. This bacteriophage belongs to the Podoviridae family. Whole genome analysis revealed that phiEaP-8 carries a 75,929 bp genomic DNA with 78 coding sequences and 5 tRNA genes. Genome comparison showed that phiEaP-8 has only 85% identity to known bacteriophages at the DNA level. PhiEaP-8 retained lytic activity up to 50 degrees C, within a pH range from 5 to 10, and under 365 nm UV light. Based on these characteristics, the bacteriophage phiEaP-8 is novel and carries potential to control both E. amylovora and E. pyrifoliae in apple and pear
Genetic Diversity of Halyomorpha halys (Hemiptera, Pentatomidae) in Korea and Comparison with COI Sequence Datasets from East Asia, Europe, and North America
The brown marmorated stinkbug, Halyomorpha halys, is an invasive insect pest in North America and Europe that attacks crop species and causes
substantial economic damage. To evaluate the genetic diversities and distributions of different H. halys populations in East Asia, North America, and
Europe, COI sequences obtained from 79 new specimens from Korea and 10 from the USA were compared with 725 existing COI sequences. In total,
45 haplotypes were detected in populations from 10 countries. Sixteen haplotypes from Korea (H34–H49) and 2 from the USA (H50 and H51) were
novel. Korean populations exhibited the 2nd highest diversity among the 10 countries, with only Greece exhibiting higher diversity. Haplotype H22
was prominent in Korea, H1 was prominent in China, Greece, Hungary, Italy, Canada, and USA, and H3 was prominent in France and Switzerland. Of
the 18 haplotypes found in Korea, 1 was shared with China (H2) and 1 with Greece (H22). Haplotype diversity patterns showed that Korean populations
were genetically distinct from populations in China, Europe, and North America. This suggested that populations in Europe and North America
arose through multiple invasions from China and that (with the exception of Greece), Korean populations did not spread to other countries. This
study represents a comprehensive analysis of H. halys populations in Korea and places these populations in a global context that includes other native
populations in East Asia and invasive populations in Europe and North America
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