The strong coupling constant
α
s
is determined from inclusive jet and dijet cross sections in neutral-current deep-inelastic
ep
scattering (DIS) measured at HERA by the H1 collaboration using ...next-to-next-to-leading order (NNLO) QCD predictions. The dependence of the NNLO predictions and of the resulting value of
α
s
(
m
Z
)
at the
Z
-boson mass
m
Z
are studied as a function of the choice of the renormalisation and factorisation scales. Using inclusive jet and dijet data together, the strong coupling constant is determined to be
α
s
(
m
Z
)
=
0.1157
(
20
)
exp
(
29
)
th
. Complementary,
α
s
(
m
Z
)
is determined together with parton distribution functions of the proton (PDFs) from jet and inclusive DIS data measured by the H1 experiment. The value
α
s
(
m
Z
)
=
0.1142
(
28
)
tot
obtained is consistent with the determination from jet data alone. The impact of the jet data on the PDFs is studied. The running of the strong coupling is tested at different values of the renormalisation scale and the results are found to be in agreement with expectations.
Charged particle multiplicity distributions in positron-proton deep inelastic scattering at a centre-of-mass energy
s
=
319
GeV are measured. The data are collected with the H1 detector at HERA ...corresponding to an integrated luminosity of 136 pb
-
1
. Charged particle multiplicities are measured as a function of photon virtuality
Q
2
, inelasticity
y
and pseudorapidity
η
in the laboratory and the hadronic centre-of-mass frames. Predictions from different Monte Carlo models are compared to the data. The first and second moments of the multiplicity distributions are determined and the KNO scaling behaviour is investigated. The multiplicity distributions as a function of
Q
2
and the Bjorken variable
x
bj
are converted to the hadron entropy
S
hadron
, and predictions from a quantum entanglement model are tested.
Combined HERA data on charm production in deep-inelastic scattering have previously been used to determine the charm-quark running mass mc(mc) in the MS‾ renormalisation scheme. Here, the same data ...are used as a function of the photon virtuality Q2 to evaluate the charm-quark running mass at different scales to one-loop order, in the context of a next-to-leading order QCD analysis. The scale dependence of the mass is found to be consistent with QCD expectations.
Résumé Introduction Avec l’augmentation du nombre d’internes en formation, la neurochirurgie française est en pleine mutation démographique. L’objectif de cette étude était de dresser un état des ...lieux des conditions de travail et des perspectives des jeunes neurochirurgiens français. Méthode Une enquête informatisée a été adressée à une liste d’internes et jeunes seniors (219 adresses mail obtenue lors de réunions d’enseignement). Le questionnaire comportait des questions sur les perspectives de carrière, la quantité de travail, le salaire, l’ambiance, la qualité de vie, l’encadrement et le travail universitaire. Résultats Au total, 78 réponses ont été obtenues entre janvier et mars 2014. Cinquante-six pour cent des jeunes seniors ont eu des difficultés à obtenir un post-internat mais en sont satisfaits à 78 %. Les seniors étaient plus nombreux à envisager une carrière libérale que les internes. Les jeunes neurochirurgiens semblaient inquiets vis-à-vis de leurs postes futurs et 33 % des sujets avaient un plan de carrière différent de leurs aspirations initiales. Le temps de travail hebdomadaire moyen de 76,8 h était jugé excessif. Le repos de sécurité était absent ou incomplet dans 91 % des cas. Par ailleurs, 81 % des sujets trouvaient leur salaire insuffisant. L’ambiance de travail était globalement bien perçue (3,7/5), de même que la qualité de vie (3,2/5). L’encadrement théorique était jugé insatisfaisant (2,43/5) de même que le temps de travail universitaire de 1,58 demi-journées mensuelle. En revanche, l’encadrement pratique était très bien perçu (3,63/5). Conclusion Ce travail apporte des éléments d’orientation pour les réformes futures, il devra être réitéré pour en évaluer l’efficacité.
Measurements of normalised cross sections for the production of photons and neutrons at very small angles with respect to the proton beam direction in deep-inelastic
e
p
scattering at HERA are ...presented as a function of the Feynman variable
x
F
and of the centre-of-mass energy of the virtual photon-proton system
W
. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of
131
pb
-
1
. The measurement is restricted to photons and neutrons in the pseudorapidity range
η
>
7.9
and covers the range of negative four momentum transfer squared at the positron vertex
6
<
Q
2
<
100
GeV
2
, of inelasticity
0.05
<
y
<
0.6
and of
70
<
W
<
245
GeV. To test the Feynman scaling hypothesis the
W
dependence of the
x
F
dependent cross sections is investigated. Predictions of deep-inelastic scattering models and of models for hadronic interactions of high energy cosmic rays are compared to the measured cross sections.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A combination is presented of all inclusive deep inelastic cross sections previously published by the H1 and ZEUS ...collaborations at HERA for neutral and charged current ... scattering for zero beam polarisation. The data were taken at proton beam energies of 920, 820, 575 and 460 GeV and an electron beam energy of 27.5 GeV. The data correspond to an integrated luminosity of about 1 fb... and span six orders of magnitude in negative four-momentum-transfer squared, ..., and Bjorken x. The correlations of the systematic uncertainties were evaluated and taken into account for the combination. The combined cross sections were input to QCD analyses at leading order, next-to-leading order and at next-to-next-to-leading order, providing a new set of parton distribution functions, called HERAPDF2.0. In addition to the experimental uncertainties, model and parameterisation uncertainties were assessed for these parton distribution functions. Variants of HERAPDF2.0 with an alternative gluon parameterisation, HERAPDF2.0AG, and using fixed-flavour-number schemes, HERAPDF2.0FF, are presented. The analysis was extended by including HERA data on charm and jet production, resulting in the variant HERAPDF2.0Jets. The inclusion of jet-production cross sections made a simultaneous determination of these parton distributions and the strong coupling constant possible, resulting in ... An extraction of ... and results on electroweak unification and scaling violations are also presented.
Streaming rendering, e.g., rendering in the cloud and streaming via a mobile connection, suffers from increased latency and unreliable connections. High quality framerate upsampling can hide these ...issues, especially when capturing shading into an atlas and transmitting it alongside geometric information. The captured shading information must consider triangle footprints and temporal stability to ensure efficient video encoding. Previous approaches only consider either temporal stability or sample distributions, but none focuses on both. With SnakeBinning, we present an efficient triangle packing approach that adjusts sample distributions and caters for temporal coherence. Using a multi‐dimensional binning approach, we enforce tight packing among triangles while creating optimal sample distributions. Our binning is built on top of hardware supported real‐time rendering where bins are mapped to individual pixels in a virtual framebuffer. Fragment shader interlock and atomic operations enforce global ordering of triangles within each bin, and thus temporal coherence according to the primitive order is achieved. Resampling the bin distribution guarantees high occupancy among all bins and a dense atlas packing. Shading samples are directly captured into the atlas using a rasterization pass, adjusting samples for perspective effects and creating a tight packing. Comparison to previous atlas packing approaches shows that our approach is faster than previous work and achieves the best sample distributions while maintaining temporal coherence. In this way, SnakeBinning achieves the highest rendering quality under equal atlas memory requirements. At the same time, its temporal coherence ensures that we require equal or less bandwidth than previous state‐of‐the‐art. As SnakeBinning outperforms previous approach in all relevant aspects, it is the preferred choice for texture‐based streaming rendering.
Tessellated Shading Streaming Hladky, J.; Seidel, H. P.; Steinberger, M.
Computer graphics forum,
July 2019, 2019-07-00, 20190701, Volume:
38, Issue:
4
Journal Article
Peer reviewed
Presenting high‐fidelity 3D content on compact portable devices with low computational power is challenging. Smartphones, tablets and head‐mounted displays (HMDs) suffer from thermal and battery‐life ...constraints and thus cannot match the render quality of desktop PCs and laptops. Streaming rendering enables to show high‐quality content but can suffer from potentially high latency. We propose an approach to efficiently capture shading samples in object space and packing them into a texture. Streaming this texture to the client, we support temporal frame up‐sampling with high fidelity, low latency and high mobility. We introduce two novel sample distribution strategies and a novel triangle representation in the shading atlas space. Since such a system requires dynamic parallelism, we propose an implementation exploiting the power of hardware‐accelerated tessellation stages. Our approach allows fast de‐coding and rendering of extrapolated views on a client device by using hardware‐accelerated interpolation between shading samples and a set of potentially visible geometry. A comparison to existing shading methods shows that our sample distributions allow better client shading quality than previous atlas streaming approaches and outperforms image‐based methods in all relevant aspects.
A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities
5.5
<
Q
2
<
80
GeV
2
and inelasticities
0.2
<
y
<
0.6
is presented, using data taken ...with the H1 detector at HERA, corresponding to an integrated luminosity of
290
pb
-
1
. Double-differential inclusive jet, dijet and trijet cross sections are measured simultaneously and are presented as a function of jet transverse momentum observables and as a function of
Q
2
. Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective
Q
2
-interval are also determined. Previous results of inclusive jet cross sections in the range
150
<
Q
2
<
15
,
000
GeV
2
are extended to low transverse jet momenta
5
<
P
T
jet
<
7
GeV
. The data are compared to predictions from perturbative QCD in next-to-leading order in the strong coupling, in approximate next-to-next-to-leading order and in full next-to-next-to-leading order. Using also the recently published H1 jet data at high values of
Q
2
, the strong coupling constant
α
s
(
M
Z
)
is determined in next-to-leading order.
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