1,617 research outputs found
Saturn's Inner Magnetospheric Convection in the View of Zebra Stripe Patterns in Energetic Electron Spectra
No full textBanded structures observed in energetic particle spectrograms in the Earth's inner radiation belt and slot region, that is, “zebra stripes,” have been resolved in the Saturnian magnetosphere with Cassini. This study implements a large-scale statistical analysis of Saturnian zebra stripe properties in association with the noon-to-midnight electric field of the inner magnetosphere to which the stripes' origin was recently established. Cassini has detected zebra stripes extending between L-shells (L) of 5–9 for more than half of the orbits that crossed inward of L = 9. The amplitude of the stripes is 15 - 20% on average above the background differential energy flux, and their age is estimated to be 20–60 hr. The regular observation of zebra stripes suggests that their regeneration and the corresponding electric field enhancements develop over timescales comparable to their estimated lifetime (days), revealing that internal processes contribute to the electric field dynamics, in addition to a solar wind-induced variability indicated by previous investigations. The flux-enhanced stripes are traced back to the dayside, preferentially from postnoon, indicating an electric field orientation from postnoon to postmidnight. Our results further suggest that the electric field's offset from the noon-midnight line is subject to both L-shell and temporal dependencies, confirming the previous inferred variability
Global solvability of the derivative nonlinear Schrödinger equation
No full textThe derivative nonlinear Schrödinger equation
(
DNLS
)
(\text {DNLS})
i
q
t
=
q
x
x
±
(
q
∗
q
2
)
x
,
a
m
p
;
q
=
q
(
x
,
t
)
,
i
=
−
1
,
q
∗
(
z
)
=
q
(
z
)
¯
,
\begin {array}{*{20}{c}} {i{q_t} = {q_{xx}} \pm {{({q^\ast }{q^2})}_x},} & {q = q(x,t), i = \sqrt { - 1} ,{q^\ast }(z) = \overline {q(z)} ,} \\ \end {array}
was first derived by plasma physicists [9,10]. This equation was used to interpret the propagation of circular polarized nonlinear Alfvén waves in plasma. Kaup and Newell obtained the soliton solutions of
DNLS
\text {DNLS}
in 1978 [5]. The author obtained the local solvability of
DNLS
\text {DNLS}
in his dissertation [6]. In this paper we obtain global existence (in time
t
t
) of Schwartz class solutions of
DNLS
\text {DNLS}
if the
L
2
{L^2}
-norm of the generic initial data
q
(
x
,
0
)
q(x,0)
is bounded.</p
Dyspepsia and irritable bowel syndrome in China: a population-based endoscopy study of prevalence and impact
No full textBackground: Dyspepsia and irritable bowel syndrome (IBS) are common in Western populations. Aim: To determine the epidemiology of dyspepsia and IBS in China. Methods: A representative sample of 18 000 adults from five regions of China were asked to complete the modified Rome II questionnaire; 20% were asked to complete the 36-item Short Form Health Survey (SF-36). Participants from Shanghai were invited to provide blood samples and undergo oesophagogastroduodenoscopy. Odds ratios (ORs) and 95% confidence intervals (CIs) were determined using a multivariate logistic regression model. Results: The survey was completed by 16 091 individuals (response rate: 89.4%). Overall, 387 participants (2.4%) had dyspepsia and 735 (4.6%) had IBS. All SF-36 dimension scores were at least five points lower in individuals with than without dyspepsia or IBS (P ≤ 0.001). In Shanghai, 1030 (32.7%) of the 3153 respondents agreed to endoscopy; neither dyspepsia nor IBS was found to be associated with reflux oesophagitis, peptic ulcer disease or Helicobacter pylori infection. Conclusions: Prevalence estimates for dyspepsia and IBS in China are lower than in Western populations. In China, dyspepsia or IBS symptoms are generally not associated with underlying organic disease.Y. Zhao, D. Zou, R. Wang, X. Ma, X. Yan, X. Man, L. Gao, J. Fang, H. Yan, X. Kang, P. Yin, Y. Hao, Q. Li, J. Dent, J. Sung, K. Halling, B. Wernersson, S. Johansson, and J. H
Observation and spin-parity determination of the X(1835) in Jpsi --> gamma K0S K0S eta
No full textWe report an observation of the process Jpsi --> gamma X(1835) -->amma K0S K0S eta at low K0SK0S mass with a statistical significance larger than 12.9 sigma using a data sample of 1.31 x 10^9 Jpsi events collected with the BESIII detector. In this region of phase space the K0SK0S system is dominantly produced through the f0(980). By performing a partial wave analysis, we determine the spin parity of the X(1835) to be JPC= 0-+. The mass and width of the observed X(1835) are 1844 ± 9(stat)+16-25(syst) MeV/c2 and 192+20-17(stat)+62-43(syst) MeV, respectively, which are consistent with the results obtained by BESIII in the channel Jpsi --> gamma pi+pi-eta'
Observation of the Decay X (3872) →π0χc1 (1P)
No full textUsing a total of 9.0 fb-1 of e+e- collision data with center-of-mass energies between 4.15 and 4.30 GeV collected by the BESIII detector, we search for the processes e+e-→γX(3872) with X(3872)→π0χcJ for J=0, 1, 2. We report the first observation of X(3872)→π0χc1, a new decay mode of the X(3872), with a statistical significance of more than 5σ for all systematic fit variations. Normalizing to the previously established process e+e-→γX(3872) with X(3872)→π+π-J/ψ, we find B(X(3872)→π0χc1)/B(X(3872)→π+π-J/ψ)=0.88-0.27+0.33±0.10, where the first error is statistical and the second is systematic. We set 90% confidence level upper limits on the corresponding ratios for the decays to π0χc0 and π0χc2 of 19 and 1.1, respectively
Rotated Half-Mode Substrate Integrated Waveguide and other Planar Integrated Structures
No full textHigh data rate communication channels are becoming more and more integrated into our increasingly technological society. Substrate Integrated Waveguides (SIW) are one planar solution available to the microwave engineer, offering a low-loss and low dispersion means of propagating these high speed, high bandwidth signals.
In this thesis, a brief synopsis of SIW structures and components is presented covering the basic waveguide propagating modes and cut-off frequencies. The main analysis techniques associated with SIWs including full wave electromagnetic modelling methods are overviewed, and the associated loss mechanisms of conduction, dielectric and radiation defined, leading to the design rules and guidelines on how best to mitigate them.
SIW antennas as both leaky-wave and radiating slots are discussed and an example of a single and dual resonating slot antenna design is presented, along with a detailed review of a novel switch beam antenna developed for use within the current WiFi bands.
The Slot SIW (or SSIW), which has a small longitudinal gap in one of the main conducting surfaces, allows easy integration of lumped elements or active devices, enabling the waveguide to be loaded with impedances or to be shorted. When the slot is shorted, the waveguide reverts back to the full SIW mode, and when partially loaded an intermediate state results. This is discussed, and the SSIW analysed with the transverse resonance technique, leading to the development of a travelling wave attenuator with the SSIW being periodically loaded with pin diodes. The application of the pin diodes required the use of a capacitive overlay, a development of flexi circuit design to allow capacitive coupling of impedances to connect to the waveguide. The overlay concept is extended further, to form novel passive bandpass filters, with the introduction of virtual vias.
A limitation of the SSIW is that the majority of the field resides within the dielectric; this allows only a limited interaction with the field at the slot. The rotated Half Mode SIW (rHMSIW), a new variant of the SIW family, places the maximum of the electric field directly on the top dielectric surface, allowing for direct interaction. The waveguide width a is now defined by the dielectric thickness, allowing for the waveguide height b to be adjustable, in normal SIWs this is the other way round; the dielectric thickness fixing the waveguide height and the waveguide width being adjustable. The rHMSIW is characterised with regard to the height and width ratios b/a and the dielectric exposed width (which is adjustable). These parameters effect the modal cut-off frequency, this is investigated and a new equation describing the fundamental mode cut-off frequency is empirically derived. Finally a test coupon which spans the Ku band is designed and measured, which required the development of a novel waveguide transition
Observation of a state in the system in the process
No full textBased on events collected with the BESIII
detector, the process is studied
using two dominant decay channels of the meson,
and
. The
is observed with a statistical significance larger than 20 in the
invariant mass spectrum, and it has a strong correlation
to a structure around 1.5/{\it c} in the
invariant mass spectrum. A simultaneous fit on the and
invariant mass spectra with the two decay modes
indicates that the mass and width of the state are /{\it c} and
, respectively. The corresponding branching
fractions are measured to be =
( and =
(, where the first uncertainties are
statistical, and the second systematic.Comment: 8 pages, 2 figure
BFAR coordinates TGFβ signaling to modulate Th9-mediated cancer immunotherapy
No full textTGFβ is essential for the generation of anti-tumor Th9 cells; on the other hand, it causes resistance against anti-tumor immunity. Despite recent progress, the underlying mechanism reconciling the double-edged effect of TGFβ signaling in Th9- mediated cancer immunotherapy remains elusive. Here, we find that TGFβ-induced down-regulation of bifunctional apoptosis regulator (BFAR) represents the key mechanism preventing the sustained activation of TGFβ signaling and thus impairing Th9 inducibility. Mechanistically, BFAR mediates K63-linked ubiquitination of TGFβR1 at K268, which is critical to activate TGFβ signaling. Thus, BFAR deficiency or K268R knock-in mutation suppresses TGFβR1 ubiquitination and Th9 differentiation, thereby inhibiting Th9-mediated cancer immunotherapy. More interestingly, BFAR-overexpressed Th9 cells exhibit promising therapeutic efficacy to curtail tumor growth and metastasis and promote the sensitivity of anti–PD-1–mediated checkpoint immunotherapy. Thus, our findings establish BFAR as a key TGFβ-regulated gene to fine-tune TGFβ signaling that causes Th9 induction insensitivity, and they highlight the translational potential of BFAR in promoting Th9-mediated cancer immunotherapy
Observation and spin-parity determination of the X(1835) in J/ψ → γK0SK0Sη
No full textWe report an observation of the process J/psi -> gamma X(1835) -> gamma(KSKS0)-K-0 eta at low (KSKS0)-K-0 mass with a statistical significance larger than 12.9s using a data sample of 1.31 x 109 J/psi events collected with the BESIII detector. In this region of phase space the (KSKS0)-K-0 system is dominantly produced through the f (0)(980). By performing a partial wave analysis, we determine the spin parity of the Xd1835_ to be J(PC) = 0(-+). The mass and width of the observed X(1835) are 1844 +/- 9(stat)(-25)(+16)(syst) MeV/c(2) and 192(-17)(+20)(sta)(-43)(+62)(syst) MeV, respectively, which are consistent with the results obtained by BESIII in the channel J/psi -> gamma pi(+)pi(-)eta'.National Basic Research Program of China 2015CB856700National Natural Science Foundation of China (NSFC) 11125525
11235011
11322544
11335008
11425524Chinese Academy of SciencesCAS Center for Excellence in Particle Physics (CCEPP)Collaborative Innovation Center for Particles and Interactions (CICPI)National Natural Science Foundation of China (NSFC)Chinese Academy of Sciences 11179007
U1232201
U1332201
KJCX2-YW-N29
KJCX2-YW-N45INPACGerman Research Foundation (DFG) Collaborative Research Center CRC-1044Istituto Nazionale di Fisica Nucleare (INFN)Turkiye Cumhuriyeti Kalkinma Bakanligi DPT2006K-120470Russian Foundation for Basic Research (RFBR)
Spanish Government 14-07-91152United States Department of Energy (DOE) DE-FG02-04ER41291
DE-FG02-05ER41374
DE-FG02-94ER40823
DESC0010118National Science Foundation (NSF)University of Groningen (RuG)Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI), DarmstadtNational Research Foundation of Korea R32-2008-000-10155-0Shanghai Key Laboratory for Particle Physics and Cosmolog
Liquid crystal seed nucleates liquid–solid phase change in ceria nanoparticles
No full textMolecular dynamics (MD) simulation was used to explore the liquid–solid (crystal) phase change of a ceria
nanoparticle. The simulations reveal that the crystalline seed, which spontaneously evolves and nucleates
crystallisation, is a liquid rather than a solid. Evidence supporting this concept includes: (a) only 3% of the
total latent heat of solidification had been liberated after 25% of the nanoparticle had (visibly) crystallised.
(b) Cerium ions, comprising the (liquid) crystal seed had the same mobility as cerium ions comprising the
amorphous regions. (c) Cerium ion mobility only started to reduce (indicative of solidification) after 25% of
the nanoparticle had crystallised. (d) Calculated radial distribution functions (RDF) revealed no long-range
structure when 25% of the nanoparticle had (visibly) crystallised. We present evidence that the concept of
a liquid crystal seed is more general phenomenon rather than applicable only to nanoceria
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