Greedy Algorithms for Multi-Queue Buffer Management with Class Segregation

In this paper, we focus on a multi-queue buffer management in which packets of different values are segregated in different queues. Our model consists of m packets values and m queues. Recently, Al-Bawani and Souza (arXiv:1103.6049v2 [cs.DS] 30 Mar 2011) presented an online multi-queue buffer management algorithm Greedy and showed that it is 2-competitive for the general m-valued case, i.e., m packet values are 0 < v_{1} < v_{2} < ... < v_{m}, and (1+v_{1}/v_{2})-competitive for the two-valued case, i.e., two packet values are 0 < v_{1} < v_{2}. For the general m-valued case, let c_i = (v_{i} + \sum_{j=1}^{i-1} 2^{j-1} v_{i-j})/(v_{i+1} + \sum_{j=1}^{i-1}2^{j-1}v_{i-j}) for 1 \leq i \leq m-1, and let c_{m}^{*} = \max_{i} c_{i}. In this paper, we precisely analyze the competitive ratio of Greedy for the general m-valued case, and show that the algorithm Greedy is (1+c_{m}^{*})-competitive.Comment: 19 page

Recent Research Progress in the Applied Microbiology Laboratory : Enzymes, Toxins and Cell-Envelope Structure of Environmental and Pathogenic Bacteria(Recent Topics of the Agricultunal Biological Science in Tohoku University)

Here we describe the current status of our studies of xylanases of Paenibacillus sp. W-61, poly (D-lactic acid) hydrolases of Amycolatopsis sp. K104-1 and Brevibacterium sp. 93, pectin lyase of plant pathogenic Pectobacterium carotovora and bi-component toxins of Staphylococcus aureus. Paenibacillus sp. W-61 utilizes xylan as a carbon source via three enzymes, of which Xyn5 plays a crucial role both in xylan utilization and in the synthesis of the other two xylanases. Understanding the roles of each xylanase in xylan degradation will help to develop an enzymatic preparation of xylose from xylan. The poly (D-lactic acid) [PLA] hydrolases of Amycolatopsis sp. K104-1 and Brevibacterium sp. 93 appear to be novel enzymes with potential for PLA recycling. We recently purified and characterized the PLA hydrolases produced by these bacteria. The plant-soft rotting bacterium P. carotovora produces pectin lyase, a potential pathogenic factor, and a bacteriocin when exposed to DNA-damaging agents. We recently determined the cis-acting regulatory sequences responsible for the DNA-damage-inducible synthesis of the enzyme and bacteriocin. Leukocidin and γ-hemolysin are bi-component toxins that lyse leukocytes and erythrocytes respectively. We describe the molecular structure and pore-forming mechanism of the toxin components encoded by the chromosome and by a phage genome. Finally, we briefly describe the cell-envelope structure of the rumen bacterium Selenomonas ruminantium and its outer membrane protein Mep45 that possibly bridges the outer membrane and the peptidoglycan. The objects of our studies include environmental bacteria (xylanolytic Paenibacillus sp. W-61 and poly (D-lactic acid)-hydrolyzing bacteria Amycolatopsis sp. K104-1 and Brevibacterium sp. 93), as well as the plant and animal pathogens, Pectobacterium carotovora and Staphylococcus aureus, respectively. Here we briefly describe the current status of our investigations into these bacteria, their extracellular enzymes (or toxins), and an outer membrane protein in the rumen bacterium Selenomonas ruminantium subsp. lactilytica. Our research also includes polyglutamate biosynthesis and the degradation enzymes of a Bacillus subtilis Natto starter, acetan (a polysaccharide produced by Acetobacter and Gluconobacter)-degrading enzymes of Paenibacillus sp. and catabolic enzymes of amino acid and polyamine in Pseudomonas aeruginosa PAOl. The topics of these projects are available on our Web site

Decomposition Characteristics of Benzene, Toluene and Xylene in an Atmospheric Pressure DC Corona Discharge II. Characteristics of Deposited By-products and Decomposition Process

Gaseous by-products and deposited material obtained from the decomposition of benzene, toluene and xylene in an atmospheric pressure DC corona discharge were minutely investigated by gas chromatograph mass spectrometry and infrared absorption spectroscopy, and the decomposition processes of benzene, toluene and xylene were estimated. It was found that carbon dioxide (CO2), carbon monoxide (CO), formic acid (HCOOH) and formic anhydride ((CHO)2) were the major gaseous by-products from benzene, toluene and xylene, while acetic formic anhydride (CH3COOCHO) and acetic acid (CH3COOH) were the major by-products from toluene and xylene. Benzaldehyde (C6H5CHO) and methyl benzaldehyde (CH3CH4CHO) were produced from toluene and xylene, respectively. It was hypothesized that the decomposition of benzene, toluene, and xylene was initiated by the production of phenyl radicals, phenyl and benzyl radicals, and methyl benzyl and methyl phenyl radicals, respectively. These radicals are deposited on electrodes, wall, etc., resulting in the polymerization of aromatic rings and the substitution of function groups. Also, those radicals are decomposed and converted into by-products described above. In addition, it is probably that benzyl and methyl benzyl radicals are precursors of C6H5CHO and CH3C6H4CHO, respectively, and that C6H5CHO and CH3C6H4CHO are decomposed, contributing to by-product production and deposition. Furthermore, some intermediate by-products, produced by the cleavage of the aromatic ring in benzene, toluene and xylene decomposition and containing O=C-O, C=O, O-H, and C-H groups, may be deposit on the electrodes

A Theory of Ferroelectric Phase Transition in SrTiO3_3 induced by Isotope Replacement

A theory to describe the dielectric anomalies and the ferroelectric phase transition induced by oxygen isotope replacement in SrTiO$_3$ is developed. The proposed model gives consistent explanation between apparently contradictory experimental results on macroscopic dielectric measurements versus microscopic lattice dynamical measurements by neutron scattering studies. The essential feature is described by a 3-state quantum order-disorder system characterizing the degenerated excited states in addition to the ground state of TiO$_6$ cluster. The effect of isotope replacement is taken into account through the tunneling frequency between the excited states. The dielectric properties are analyzed by the mean field approximation (MFA), which gives qualitative agreements with experimental results throughout full range of the isotope concentration.The phase diagram in the temperature-tunneling frequencycoordinate is studied by a QMC method to confirm the qualitative validity of the MFA analysis.Comment: 26 pages, 8 figure

Novel pH-dependent regulation of human cytosolic sialidase 2 (NEU2) activities by siastatin B and structural prediction of NEU2/siastatin B complex

Human cytosolic sialidase (Neuraminidase 2, NEU2) catalyzes the removal of terminal sialic acid residues from glycoconjugates. The effect of siastatin B, known as a sialidase inhibitor, has not been evaluated toward human NEU2 yet. We studied the regulation of NEU2 activity by siastatin B in vitro and predicted the interaction in silico. Inhibitory and stabilizing effects of siastatin B were analyzed in comparison with DANA (2-deoxy-2,3-dehydro-N-acetylneuraminic acid) toward 4-umbelliferyl N-acetylneuraminic acid (4-MU-NANA)- and α2,3-sialyllactose-degrading activities of recombinant NEU2 produced by E. coli GST-fusion gene expression. Siastatin B exhibited to have higher competitive inhibitory activity toward NEU2 than DANA at pH 4.0. We also revealed the stabilizing effect of siastatin B toward NEU2 activity at acidic pH. Docking model was constructed on the basis of the crystal structure of NEU2/DANA complex (PDB code: 1VCU). Molecular docking predicted that electrostatic neutralization of E111 and E218 residues of the active pocket should not prevent siastatin B from binding at pH 4.0. The imino group (1NH) of siastatin B can also interact with D46, neutralized at pH 4.0. Siastatin B was suggested to have higher affinity to the active pocket of NEU2 than DANA, although it has no C7–9 fragment corresponding to that of DANA. We demonstrated here the pH-dependent affinity of siastatin B toward NEU2 to exhibit potent inhibitory and stabilizing activities. Molecular interaction between siastatin B and NEU2 will be utilized to develop specific inhibitors and stabilizers (chemical chaperones) not only for NEU2 but also the other human sialidases, including NEU1, NEU3 and NEU4, based on homology modeling

The Efficacy and Safety of Propiverine Hydrochloride in Patients with Overactive Bladder Symptoms Who Poorly Responded to Previous Anticholinergic Agents

Objectives. To prospectively examine the efficacy and safety of propiverine hydrochloride in patients with overactive bladder (OAB) symptoms who poorly responded to previous treatment with solifenacin, tolterodine or imidafenacin. Methods. Patients aged ≥20 with persisting OAB symptoms (≥6 in OAB symptom score (OABSS)) even after at least 4-week treatment using solifenacin, tolterodine or imidafenacin were enrolled. Propiverine 20 mg/day was administered for 12 weeks to 70 patients who desired the further improvement of OAB symptoms and 3 who had intolerable adverse events of previous drugs. The OABSS and postvoid residual urine volume (PVR) were determined before and at 4 and 12 weeks of treatment. Results. Of 73 patients enrolled (29 males and 44 females, median age 71 years), 52 completed the protocol treatment. The OABSS was significantly improved by propiverine treatment (9.0 at baseline, 6.2 at 4 weeks, 6.3 at 12 weeks (P < 0.001)). The scores of OAB symptoms (nighttime frequency, urgency and urge incontinence) except daytime frequency also improved significantly. No increase in PVR was observed. The most frequent adverse event was dry mouth (13.7%), followed by constipation (6.8%). Conclusions. Propiverine is useful to improve OAB for patients who poorly respond to solifenacin, tolterodine or imidafenacin

Substellar Companions to Evolved Intermediate-Mass Stars: HD 145457 and HD 180314

We report the detections of two substellar companions orbiting around evolved intermediate-mass stars from precise Doppler measurements at Subaru Telescope and Okayama Astrophysical Observatory. HD 145457 is a K0 giant with a mass of 1.9 M_sun and has a planet of minimum mass m_2sini=2.9 M_J orbiting with period of P=176 d and eccentricity of e=0.11. HD 180314 is also a K0 giant with 2.6 M_sun and hosts a substellar companion of m_2sin i=22 M_J, which falls in brown-dwarf mass regime, in an orbit with P=396 d and e=0.26. HD 145457 b is one of the innermost planets and HD 180314 b is the seventh candidate of brown-dwarf-mass companion found around intermediate-mass evolved stars.Comment: 16 pages, 4 figures, accepted for publication in PAS