5,418 research outputs found
PACIAE 2.0: An updated parton and hadron cascade model (program) for the relativistic nuclear collisions
We have updated the parton and hadron cascade model PACIAE for the
relativistic nuclear collisions, from based on JETSET 6.4 and PYTHIA 5.7 to
based on PYTHIA 6.4, and renamed as PACIAE 2.0. The main physics concerning the
stages of the parton initiation, parton rescattering, hadronization, and hadron
rescattering were discussed. The structures of the programs were briefly
explained. In addition, some calculated examples were compared with the
experimental data. It turns out that this model (program) works well.Comment: 23 pages, 7 figure
Hemodynamic and morphological vasculature response to a burn monitored using a combined dual-wavelength laser speckle and optical microangiography imaging system
A multi-functional imaging system capable of determining relative changes in blood flow, hemoglobin concentration, and morphological features of the blood vasculature is demonstrated. The system combines two non-invasive imaging techniques, a dual-wavelength laser speckle contrast imaging (2-LSI) and an optical microangiography (OMAG) system. 2-LSI is used to monitor the changes in the dynamic blood flow and the changes in the concentration of oxygenated (HbO), deoxygenated (Hb) and total hemoglobin (HbT). The OMAG system is used to acquire high resolution images of the functional blood vessel network. The vessel area density (VAD) is used to quantify the blood vessel network morphology, specifically the capillary recruitment. The proposed multi-functional system is employed to assess the blood perfusion status from a mouse pinna before and immediately after a burn injury. To our knowledge, this is the first non-invasive, non-contact and multifunctional imaging modality that can simultaneously measure variations of several blood perfusion parameters
The role of extracellular polymers on Staphylococcus epidermidis biofilm biomass and metabolic activity
Staphylococcus epidermidis is now well established as being a major nosocomial
pathogen, associated with indwelling medical devices. Its major virulence factor is related with
the ability to adhere to indwelling medical devices, with consequent biofilm formation.
The present study aimed to evaluate the role of polysaccharides and proteins on
biofilm biomass and metabolic activity of five S. epidermidis clinical isolates. For this purpose,
S. epidermis biofilms, formed on acrylic coupons, were characterized in terms of total biofilm
biomass, determined through crystal violet assay, cell concentration, established by colony
forming units (CFU) enumeration, and biofilm matrix composition, which was assessed for
polysaccharides and proteins content. Biofilm metabolic activity was evaluated by two distinct
methods: glucose uptake and XTT reduction assays. According to the results, S. epidermidis
strains revealed different abilities for biofilm formation. In fact, some strains were able to form
thicker biofilms than others and this is important because biofilm formation is considered one
of the major virulence factors of S. epidermidis species. S. epidermidis 1457 was the strain that
produced the larger amount of biofilm and strain LE7 was the lowest biofilm producer, and
these were also the highest and the lowest polysaccharides producers, respectively. This
suggests a certain degree of correlation between exopolysaccharides production and total
amount of biomass formed. Besides, comparing the results obtained, in terms of
exopolysaccharides production and biofilm cellular activity, it seems clear that a strong
production of exopolysaccharides can lead to a decrease in the metabolic activity of cells,
which was the case of S. epidermidis 1457. The protein concentration also varied among
strains, with the biofilm matrix of S. epidermidis 9142 presenting a higher concentration of
proteins comparing to the remaining strains. This fact indicates the different levels of
importance that matrix proteins can have on biofilm composition among strains albeit overall,
it is suggested that extracellular protein production it is not a determinant factor for biofilm
total biomass, despite its qualitative value.
In conclusion, this work provided a reliable approach for a better understanding of S.
epidermidis biofilms composition and metabolic activity
When things matter: A survey on data-centric Internet of Things
With the recent advances in radio-frequency identification (RFID), low-cost wireless sensor devices, and Web technologies, the Internet of Things (IoT) approach has gained momentum in connecting everyday objects to the Internet and facilitating machine-to-human and machine-to-machine communication with the physical world. IoT offers the capability to connect and integrate both digital and physical entities, enabling a whole new class of applications and services, but several significant challenges need to be addressed before these applications and services can be fully realized. A fundamental challenge centers around managing IoT data, typically produced in dynamic and volatile environments, which is not only extremely large in scale and volume, but also noisy and continuous. This paper reviews the main techniques and state-of-the-art research efforts in IoT from data-centric perspectives, including data stream processing, data storage models, complex event processing, and searching in IoT. Open research issues for IoT data management are also discussed
Three-loop HTL QCD thermodynamics
The hard-thermal-loop perturbation theory (HTLpt) framework is used to
calculate the thermodynamic functions of a quark-gluon plasma to three-loop
order. This is the highest order accessible by finite temperature perturbation
theory applied to a non-Abelian gauge theory before the high-temperature
infrared catastrophe. All ultraviolet divergences are eliminated by
renormalization of the vacuum, the HTL mass parameters, and the strong coupling
constant. After choosing a prescription for the mass parameters, the three-loop
results for the pressure and trace anomaly are found to be in very good
agreement with recent lattice data down to , which are
temperatures accessible by current and forthcoming heavy-ion collision
experiments.Comment: 27 pages, 11 figures; corresponds with published version in JHE
Regional mitochondrial DNA and cell-type changes in post-mortem brains of non-diabetic Alzheimer’s disease are not present in diabetic Alzheimer’s disease
Background: Mitochondrial dysfunction is implicated in both diabetes and Alzheimer’s disease (AD), and diabetes also increases the risk of AD, however the combined impact of AD and diabetes on brain mitochondria is unknown. The purpose of this study was to test the hypothesis that the combination of both diabetes and AD exacerbates mitochondrial dysfunction.
Methods: Post-mortem human brains (n=74), were used to determine mitochondrial DNA (mtDNA) content of cerebellum, frontal cortex and parietal cortex by quantifying absolute mtDNA copy number/cell using real time qPCR. mtDNA content was compared between diabetic and non-diabetic cases representing non-cognitively impaired controls (NCI), mildly cognitively impaired (MCI) and AD. A subset of parietal cortex samples was used to quantify mRNAs corresponding to cell types and mitochondrial function. Immune-staining of parietal cortex sections followed by semi-automated stereological assessment was performed to assess cell types.
Results. Using mtDNA as an indicator of mitochondrial content, we observed significant regional variation, being highest in the parietal cortex, and lowest in the cerebellum. In the absence of diabetes, AD cases had decreased parietal cortex mtDNA, reduced MAP2 (neuronal) mRNA and increased GFAP (astrocyte) mRNA, relative to NCI. However, in the presence of both diabetes and AD, we did not observe these changes in the parietal cortex. Irrespective of cognitive status, all 3 brain regions in diabetic cases had significantly higher mtDNA than the non-diabetic cases.
Conclusion. Our data show that the parietal cortex has the highest mitochondrial content but is also the most vulnerable to changes in AD, as shown by reduced mtDNA and neurones in this region. In contrast, when patients have both diabetes and AD, the AD associated parietal cortex changes are no longer seen, suggesting that the pathology observed in diabetic AD may be different to that seen in non-diabetic AD. The lack of clear functional changes in mitochondrial parameters in diabetic AD suggest that there may be different mechanisms contributing to cognitive impairment in diabetes and their impact on the respective disease neuro-pathologies remain to be fully understood
Tri-bimaximal-Cabibbo Mixing
Recent measurements of the lepton mixing angle by the Daya Bay
and RENO reactor experiments are consistent with the relationship
where is the Cabibbo angle.
We propose Tri-bimaximal-Cabibbo (TBC) mixing, in which , and . We show that TBC mixing may arise approximately from
Tri-bimaximal, Bi-maximal or Golden Ratio neutrino mixing, together with
Cabibbo-like charged lepton corrections arising from a Pati-Salam gauge group,
leading to predictions for the CP-violating phase of , respectively. Alternatively, we show that TBC neutrino
mixing may realised accurately using the type I see-saw mechanism with
partially constrained sequential right-handed neutrino dominance, assuming a
family symmetry which is broken by a flavon common to quarks and neutrinos.Comment: 16 pages. References added, minor change
Search for C-parity violation in and
Using events recorded in
collisions at 3.686 GeV with the BESIII at the BEPCII collider, we
present searches for C-parity violation in and decays via . No significant
signals are observed in either channel. Upper limits on the branching fractions
are set to be and
at the 90\%
confidence level. The former is one order of magnitude more stringent than the
previous upper limit, and the latter represents the first limit on this decay
channel.Comment: 7 pages, 2 figure
Observation of at BESIII
Using events collected with the BESIII detector
at the BEPCII storage rings, we observe for the first time the process
,
with a significance of ( including systematic
uncertainties). The product branching fraction of is measured to be
, where the first error is statistical and the
second is systematic. This measurement provides information on the
production near threshold coupling to and improves the understanding
of the dynamics of decays to four body processes.Comment: 8 pages, 7 figure
Observation of the state in at BESIII
We report the observation of the in the process with a statistical
significance of , in data samples at center-of-mass energies
4.230, 4.260, 4.360, 4.420 and 4.600~GeV collected with the BESIII
detector at the BEPCII electron positron collider. The measured mass of the
is ~MeV/, where the first error is
statistical and the second systematic, and the width is less than ~MeV at
the 90\% confidence level. The products of the Born cross sections for
and the branching ratio are also measured. These measurements are in good
agreement with the assignment of the as the charmonium
state.Comment: 7 pages, 3 figures, version to appear in Phys. Rev. Let
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