11,584 research outputs found
Impact of soft handover and pilot pollution on video telephony in a commercial network
Soft handover (SHO) provides better support for user mobility. The quality of service (QoS) to the mobile wireless subscribers can also grant benefits from SHO. To analyze the impact of SHO on the circuit switched (CS) video telephony (VT); real-time measurements have been conducted on a commercial WCDMA mobile network in the CBD of Sydney, Australia. Live measurement provides a practical approach to evaluate performance of commercial network. The obtained SHO gain implies that better QoS can be achieved. Furthermore, the negative impact of pilot pollution on radio link quality has been demonstrated in this paper. ©2010 IEEE
A study on nitrogen removal efficiency of Pseudomonas stutzeri strains isolated from an anaerobic/anoxic/oxic wastewater treatment process
In order to improve the nitrogen removal efficiency in an anaerobic/anoxic/oxic treatment plant, a strain with high nitrification and denitrification capability was isolated from a specific anaerobic/anoxic/oxic treatment process. The characteristics of isolate were experimentally analyzed. By using the nitrogen balance method, the total nitrogen loss was calculated to be 40.1% (w/w) when the carbon source was citric acid with a C/N ratio of 5. Meanwhile, the isolated strain was identified by 16S rDNA to be a Pseudomonas stutzeri with a similarity of 99%. Varying the initial TN, the C/N, the pH value and the ambient temperature in the reaction system, the efficiency of nitrogen removal was studied. The results showed that the highest efficiency occurred when the C/N was 12, the pH value was 7 and the temperature was 32°C. The results were also compared to the practically monitoring data coming with a good agreement. Consequently, it is viable to improve the nitrogen removal efficiency by varying the reaction conditions
Electrical stimulation of somatic afferent nerves in the foot increases bladder capacity in neurogenic bladder patients after sigmoid cystoplasty
CNS activity of Pokeweed Anti-viral Protein (PAP) in mice infected with Lymphocytic Choriomeningitis Virus (LCMV)
BACKGROUND: Others and we have previously described the potent in vivo and in vitro activity of the broad-spectrum antiviral agent PAP (Pokeweed antiviral protein) against a wide range of viruses. The purpose of the present study was to further elucidate the anti-viral spectrum of PAP by examining its effects on the survival of mice challenged with lymphocytic choriomeningitis virus (LCMV). METHODS: We examined the therapeutic effect of PAP in CBA mice inoculated with intracerebral injections of the WE54 strain of LCMV at a 1000 PFU dose level that is lethal to 100% of mice within 7–9 days. Mice were treated either with vehicle or PAP administered intraperitoneally 24 hours prior to, 1 hour prior to and 24 hours, 48 hours 72 hours and 96 hours after virus inoculation. RESULTS: PAP exhibits significant in vivo anti- LCMV activity in mice challenged intracerebrally with an otherwise invariably fatal dose of LCMV. At non-toxic dose levels, PAP significantly prolonged survival in the absence of the majority of disease-associated symptoms. The median survival time of PAP-treated mice was >21 days as opposed to 7 days median survival for the control (p = 0.0069). CONCLUSION: Our results presented herein provide unprecedented experimental evidence that PAP exhibits antiviral activity in the CNS of LCMV-infected mice
The origin of defects induced in ultra-pure germanium by Electron Beam Deposition
The creation of point defects in the crystal lattices of various
semiconductors by subthreshold events has been reported on by a number of
groups. These observations have been made in great detail using sensitive
electrical techniques but there is still much that needs to be clarified.
Experiments using Ge and Si were performed that demonstrate that energetic
particles, the products of collisions in the electron beam, were responsible
for the majority of electron-beam deposition (EBD) induced defects in a
two-step energy transfer process. Lowering the number of collisions of these
energetic particles with the semiconductor during metal deposition was
accomplished using a combination of static shields and superior vacuum
resulting in devices with defect concentrations lower than cm, the measurement limit of our deep level transient
spectroscopy (DLTS) system. High energy electrons and photons that samples are
typically exposed to were not influenced by the shields as most of these
particles originate at the metal target thus eliminating these particles as
possible damage causing agents. It remains unclear how packets of energy that
can sometimes be as small of 2eV travel up to a m into the material while
still retaining enough energy, that is, in the order of 1eV, to cause changes
in the crystal. The manipulation of this defect causing phenomenon may hold the
key to developing defect free material for future applications.Comment: 18 pages, 9 figure
Composition dependence of bulk superconductivity in YFe2Ge2
In the layered iron-based superconductor YFe2Ge2, a high Sommerfeld ratio of
~100 mJ/molK^2 and a T^(3/2) temperature dependence of the electrical
resistivity at low temperature T indicate strong electronic correlations and
point towards an unconventional pairing state. We have investigated the role of
composition and annealing conditions in optimizing the growth of high-quality
YFe2Ge2. Our findings confirm that bulk superconductivity is observed in
samples with disorder scattering rates less than 2 k_B T_c/hbar. Fe deficiency
on the Fe site is identified as the dominant source of disorder, which can be
minimised by precipitating from a slightly iron-rich melt, following by
annealing
Clathrin light chain diversity regulates membrane deformation in vitro and synaptic vesicle formation in vivo
Clathrin light chain (CLC) subunits in vertebrates are encoded by paralogous genes CLTA and CLTB, and both gene products are alternatively spliced in neurons. To understand how this CLC diversity influences neuronal clathrin function, we characterized the biophysical properties of clathrin comprising individual CLC variants for correlation with neuronal phenotypes of mice lacking either CLC-encoding gene. CLC splice variants differentially influenced clathrin knee conformation within assemblies, and clathrin with neuronal CLC mixtures was more effective in membrane deformation than clathrin with single neuronal isoforms nCLCa or nCLCb. Correspondingly, electrophysiological recordings revealed that neurons from mice lacking nCLCa or nCLCb were both defective in synaptic vesicle replenishment. Mice with only nCLCb had a reduced synaptic vesicle pool and impaired neurotransmission compared to WT mice, while nCLCa-only mice had increased synaptic vesicle numbers, restoring normal neurotransmission. These findings highlight differences between the CLC isoforms and show that isoform mixing influences tissue-specific clathrin activity in neurons, which requires their functional balance
Extended RDF: Computability and Complexity Issues
ERDF stable model semantics is a recently proposed semantics for
ERDF ontologies and a faithful extension of RDFS semantics on RDF graphs.
In this paper, we elaborate on the computability and complexity issues of the
ERDF stable model semantics. Based on the undecidability result of ERDF
stable model semantics, decidability under this semantics cannot be achieved,
unless ERDF ontologies of restricted syntax are considered. Therefore, we
propose a slightly modified semantics for ERDF ontologies, called ERDF #n-
stable model semantics. We show that entailment under this semantics is, in
general, decidable and also extends RDFS entailment. Equivalence statements
between the two semantics are provided. Additionally, we provide algorithms
that compute the ERDF #n-stable models of syntax-restricted and general
ERDF ontologies. Further, we provide complexity results for the ERDF #nstable
model semantics on syntax-restricted and general ERDF ontologies.
Finally, we provide complexity results for the ERDF stable model semantics
on syntax-restricted ERDF ontologies
X-ray Time Lags in TeV Blazars
We use Monte Carlo/Fokker-Planck simulations to study the X-ray time lags.
Our results show that soft lags will be observed as long as the decay of the
flare is dominated by radiative cooling, even when acceleration and cooling
timescales are similar. Hard lags can be produced in presence of a competitive
achromatic particle energy loss mechanism if the acceleration process operates
on a timescale such that particles are slowly moved towards higher energy while
the flare evolves. In this type of scenario, the {\gamma} -ray/X-ray quadratic
relation is also reproduced.Comment: 4 pages, 6 figures, Proceeding of `Multiwavelength Variability of
Blazars', Guangzhou, Chin
Serotonin and corticosterone rhythms in mice exposed to cigarette smoke and in patients with COPD:implication for COPD-associated neuropathogenesis
The circadian timing system controls daily rhythms of physiology and behavior, and disruption of clock function can trigger stressful life events. Daily exposure to cigarette smoke (CS) can lead to alteration in diverse biological and physiological processes. Smoking is associated with mood disorders, including depression and anxiety. Patients with chronic obstructive pulmonary disease (COPD) have abnormal circadian rhythms, reflected by daily changes in respiratory symptoms and lung function. Corticosterone (CORT) is an adrenal steroid that plays a considerable role in stress and anti-inflammatory responses. Serotonin (5-hydroxytryptamine; 5HT) is a neurohormone, which plays a role in sleep/wake regulation and affective disorders. Secretion of stress hormones (CORT and 5HT) is under the control of the circadian clock in the suprachiasmatic nucleus. Since smoking is a contributing factor in the development of COPD, we hypothesize that CS can affect circadian rhythms of CORT and 5HT secretion leading to sleep and mood disorders in smokers and patients with COPD. We measured the daily rhythms of plasma CORT and 5HT in mice following acute (3 d), sub-chronic (10 d) or chronic (6 mo) CS exposure and in plasma from non-smokers, smokers and patients with COPD. Acute and chronic CS exposure affected both the timing (peak phase) and amplitude of the daily rhythm of plasma CORT and 5HT in mice. Acute CS appeared to have subtle time-dependent effects on CORT levels but more pronounced effects on 5HT. As compared with CORT, plasma 5HT was slightly elevated in smokers but was reduced in patients with COPD. Thus, the effects of CS on plasma 5HT were consistent between mice and patients with COPD. Together, these data reveal a significant impact of CS exposure on rhythms of stress hormone secretion and subsequent detrimental effects on cognitive function, depression-like behavior, mood/anxiety and sleep quality in smokers and patients with COPD
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