31 research outputs found
N-(2,3,4-TrifluoroÂphenÂyl)morpholine-4-carboxamide
In title molÂecule, C11H11F3N2O2, the central –N—C(=O)—N– unit is essentially planar [maximum deviation = 0.013 (2) Å] and forms a dihedral angle of 57.33 (9)° with the benzene ring. The morpholine ring is in a chair conformation. In the crystal, molÂecules are linked into chains along [001] by N—H⋯O hydrogen bonds
L-CAD: Language-based Colorization with Any-level Descriptions using Diffusion Priors
Language-based colorization produces plausible and visually pleasing colors
under the guidance of user-friendly natural language descriptions. Previous
methods implicitly assume that users provide comprehensive color descriptions
for most of the objects in the image, which leads to suboptimal performance. In
this paper, we propose a unified model to perform language-based colorization
with any-level descriptions. We leverage the pretrained cross-modality
generative model for its robust language understanding and rich color priors to
handle the inherent ambiguity of any-level descriptions. We further design
modules to align with input conditions to preserve local spatial structures and
prevent the ghosting effect. With the proposed novel sampling strategy, our
model achieves instance-aware colorization in diverse and complex scenarios.
Extensive experimental results demonstrate our advantages of effectively
handling any-level descriptions and outperforming both language-based and
automatic colorization methods. The code and pretrained models are available
at: https://github.com/changzheng123/L-CAD
N-(2,3,4-TrifluoroÂphenÂyl)pyrrolidine-1-carboxamide
In the title compound, C11H11F3N2O, a urea derivative, the best plane through the pyrrole ring makes a dihedral angle of 9.69 (13)° with the benzene ring. The amino H atom is shielded, so that it is not involved in any hydrogen-bonding interÂactions
Confirmation of the Double Charm Baryon Xi_cc+ via its Decay to p D+ K-
We observes a signal for the double charm baryon Xi_cc+ in the charged decay
mode Xi_cc+ -> p D+ K- to complement the previously reported decay Xi_cc+ ->
Lambda_c K- pi+ in data from SELEX, the charm hadro-production experiment
(E781) at Fermilab. In this new decay mode we observe an excess of 5.62 events
over an expected background estimated by event mixing to be 1.38+/-0.13 events.
The Poisson probability that a background fluctuation can produce the apparent
signal is less than 6.4E-4. The observed mass of this state is
(3518+/-3)MeV/c^2, consistent with the published result. Averaging the two
results gives a mass of (3518.7+/-1.7)MeV/c^2. The observation of this new weak
decay mode confirms the previous SELEX suggestion that this state is a double
charm baryon. The relative branching ratio Gamma(Xi_cc+ -> pD+K-)/Gamma(Xi_cc+
-> Lambda_c K- pi+) = 0.36+/-0.21.Comment: 11 pages, 6 included eps figures. v2 includes improved statistical
method to determine significance of observation. Submitted to PL
First Observation of the Doubly Charmed Baryon Xi_cc^+
We observe a signal for the doubly charmed baryon Xi_cc^+ in the charged
decay mode Xi_cc^+ --> Lambda_c^+ K- pi+ in data from SELEX, the charm
hadro-production experiment at Fermilab. We observe an excess of 15.9 events
over an expected background of 6.1 +/- 0.5 events, a statistical significance
of 6.3sigma. The observed mass of this state is (3519 +/- 1) MeV/c^2. The
Gaussian mass width of this state is 3MeV/c^2, consistent with resolution; its
lifetime is less than 33fsec at 90% confidence.Comment: 5 pages, 3 figures, accepted for publication in Physical Review
Letter
First Measurement of pi e -> pi e gamma Pion Virtual Compton Scattering
Pion Virtual Compton Scattering (VCS) via the reaction pi e --> pi e gamma
was observed in the Fermilab E781 SELEX experiment. SELEX used a 600 GeV/c pi-
beam incident on target atomic electrons, detecting the incident pi- and the
final state pi-, electron and gamma. Theoretical predictions based on chiral
perturbation theory are incorporated into a Monte Carlo simulation of the
experiment and are compared to the data. The number of reconstructed events (9)
and their distribution with respect to the kinematic variables (for the
kinematic region studied) are in reasonable accord with the predictions. The
corresponding pi- VCS experimental cross section is sigma=38.8+-13 nb, in
agreement with the theoretical expectation sigma=34.7 nb.Comment: 10 pages, 12 figures, 4 tables, 25 references, SELEX home page is
http://fn781a.fnal.gov/, revised July 21, 2002 in response to journal referee
Comment
China’s internationalized higher education during Covid-19: Collective student autoethnography
This is an accepted manuscript of an article published by Springer in Postdigital Science and Education on 08/05/2020, available online: https://doi.org/10.1007/s42438-020-00128-1
The accepted version of the publication may differ from the final published version.This article presents 15 autoethnographical texts detailing student experiences at Beijing Normal University in the midst of the Covid-19 pandemic. Contributions have been collected over 6 weeks between 15 February and 1 April 2020, edited by Hejia Wang (assisted by Moses Oladele Ogunniran and Yingying Huang), and supervised by Michael Peters. Through shared in-depth empirical feelings and representations from a wide variety of cultural, historical, and social contexts, the article outlines an answer to the question: How do students, connected virtually but separated physically in an internationalized university, deal with disruption brought about by the Covid-19 pandemic? Student testimonies offer reflections on Covid-19 and Chinese international education, experiences of online teaching and learning, reflections on university coping mechanisms, an account of realities and feelings related to changes in academic life, and discussions on coping strategies in Chinese international higher education. Contributors expose their individual feelings, effects, benefits, challenges, and risk management strategies. Collected at the peak of the Covid-19 pandemic, these testimonies are unable to offer systemic answers to challenges facing the whole world. However, these experiences and feelings will provide important inputs to global discussions about the future of the world, after Covid-19.Published onlin
A Search for Light Super Symmetric Baryons
We have searched for the production and decay of light super-symmetric
baryons produced in 800 GeV/c proton copper interactions in a charged hyperon
beam experiment. We observe no evidence for the decays R+(uud \g^~) -> S(uds
\g^~) pi+ and X-(ssd \g^~) -> S(uds \g^~) pi- in the predicted parent mass and
lifetime ranges of 1700-2500 Mev/c2 and 50-500 ps. Production upper limits for
R+ at xF=0.47, Pt=1.4 GeV/c2 and X- at xF=0.48, Pt=0.65 GeV/c2 of less than
10^-3 of all charged secondary particles produced are obtained for all but the
highest masses and shortest lifetimes predicted.Comment: 9 pages, uuencoded postscript 4 figures uuencoded, tar-compressed
file (submitted to PRL
Hadronic Production of Lambda_c from 600 GeV/c pion, sigma and proton beams
We present data from Fermilab experiment E781 (SELEX) on the hadroproduction
asymmetry for anti-Lambda_c compared to Lambda_c+ as a function of xF and pt2
distributions for Lambda_c+. These data were measured in the same apparatus
using incident pi-, sigma- beams at 600 GeV/c and proton beam at 540 GeV/c. The
asymmetry is studied as a function of xF. In the forward hemisphere with xF >=
0.2 both baryon beams exhibit very strong preference for producing charm
baryons rather than charm antibaryons, while the pion beam asymmetry is much
smaller. In this energy regime the results show that beam fragments play a
major role in the kinematics of Lambda_c formation, as suggested by the leading
quark picture.Comment: 6 pages, 5 figures (postscript), RevTeX, submitted to Phy. Rev. Let
First Observation of the Cabibbo-suppressed Decays Xi_c+ -> Sigma+ pi- pi+ and Xi_c+ -> Sigma- pi+ pi+ and Measurement of their Branching Ratios
We report the first observation of two Cabibbo-suppressed decay modes, Xi_c+
-> Sigma+ pi- pi+ and Xi_c+ -> Sigma- pi+ pi+. We observe 59+/-14 over a
background of 87, and 22+/-8 over a background of 13 events, respectively, for
the signals. The data were accumulated using the SELEX spectrometer during the
1996-1997 fixed target run at Fermilab, chiefly from a 600GeV/c Sigma- beam.
The branching ratios of the decays relative to the Cabibbo--favored Xi_c+ ->
Xi- pi+ pi+ are measured to be B(Xi_c+ -> Sigma+ pi- pi+)/B(Xi_c+ -> Xi- pi+
pi+) = 0.48+/-0.20, and B(Xi_c+ -> Sigma- pi+ pi+)/B(Xi_c+ -> Xi- pi+ pi+) =
0.18+/-0.09, respectively. We also report branching ratios for the same decay
modes of the Lambda_c+ relative to Lambda_c+ -> p K- pi+.Comment: 15 pages, 5 figures, version 2 as accepted in PL