2,579 research outputs found
Potential of the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor for the monitoring of terrestrial chlorophyll fluorescence
Global monitoring of sun-induced chlorophyll fluorescence (SIF) is improving our knowledge about the photosynthetic functioning of terrestrial ecosystems. The feasibility of SIF retrievals from spaceborne atmospheric spectrometers has been demonstrated by a number of studies in the last years. In this work, we investigate the potential of the upcoming TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor satellite mission for SIF retrieval. TROPOMI will sample the 675–775 nm spectral window with a spectral resolution of 0.5 nm and a pixel size of 7 km × 7 km. We use an extensive set of simulated TROPOMI data in order to assess the uncertainty of single SIF retrievals and subsequent spatio-temporal composites. Our results illustrate the enormous improvement in SIF monitoring achievable with TROPOMI with respect to comparable spectrometers currently in-flight, such as the Global Ozone Monitoring Experiment-2 (GOME-2) instrument. We find that TROPOMI can reduce global uncertainties in SIF mapping by more than a factor of 2 with respect to GOME-2, which comes together with an approximately 5-fold improvement in spatial sampling. Finally, we discuss the potential of TROPOMI to map other important vegetation parameters at a global scale with moderate spatial resolution and short revisit time. Those include leaf photosynthetic pigments and proxies for canopy structure, which will complement SIF retrievals for a self-contained description of vegetation condition and functioning
Giant crystal-electric-field effect and complex magnetic behavior in single-crystalline CeRh3Si2
Single-crystalline CeRh3Si2 was investigated by means of x-ray diffraction,
magnetic susceptibility, magnetization, electrical resistivity, and specific
heat measurements carried out in wide temperature and magnetic field ranges.
Moreover, the electronic structure of the compound was studied at room
temperature by cerium core-level x-ray photoemission spectroscopy (XPS). The
physical properties were analyzed in terms of crystalline electric field and
compared with results of ab-initio band structure calculations performed within
the density functional theory approach. The compound was found to crystallize
in the orthorhombic unit cell of the ErRh3Si2 type (space group Imma -- No.74,
Pearson symbol: oI24) with the lattice parameters: a = 7.1330(14) A, b =
9.7340(19) A, and c = 5.6040(11) A. Analysis of the magnetic and XPS data
revealed the presence of well localized magnetic moments of trivalent cerium
ions. All physical properties were found to be highly anisotropic over the
whole temperature range studied, and influenced by exceptionally strong
crystalline electric field with the overall splitting of the 4f1 ground
multiplet exceeding 5700 K. Antiferromagnetic order of the cerium magnetic
moments at TN = 4.70(1)K and their subsequent spin rearrangement at Tt =
4.48(1) K manifest themselves as distinct anomalies in the temperature
characteristics of all investigated physical properties and exhibit complex
evolution in an external magnetic field. A tentative magnetic B-T phase
diagram, constructed for B parallel to the b-axis being the easy magnetization
direction, shows very complex magnetic behavior of CeRh3Si2, similar to that
recently reported for an isostructural compound CeIr3Si2. The electronic band
structure calculations corroborated the antiferromagnetic ordering of the
cerium magnetic moments and well reproduced the experimental XPS valence band
spectrum.Comment: 32 pages, 12 figures, to appear in Physical Review
Histopathologic parameters as predictors of response to endoscopic sinus surgery in nonallergic patients with chronic rhinosinusitis
OBJECTIVE: To estimate the predictable value of histopathologic parameters in chronic rhinosinusitis (CRS) for response to endoscopic sinus surgery (ESS). - - - - - STUDY DESIGN: Symptomatology was rated in 100 patients prior to as well as 12 and 24 months after surgery. Specimens taken during the procedure were examined and scored for goblet cells, subepithelial thickening, mast cells, and eosinophils. Multiple regression analysis was performed to predict the total score of subjective symptoms before treatment by histopathologic parameters. The correlation between histopathologic parameters and postoperative symptoms was then evaluated. - - - - - RESULTS: Goblet cells were the best predictor correlating with 5 symptoms. Subepithelial thickening correlated with 4 symptoms. Mast cell infiltration correlated with 3 symptoms. Eosinophilic infiltration correlated with only one symptom (P<0.05). - - - - - CONCLUSION: Certain histopathologic parameters in CRS are predictive of favorable response to ESS. - - - - - SIGNIFICANCE: Pathologic evaluation may help the ENT surgeon to predict the persistence of certain CRS symptoms after ESS, even in patients at low risk for surgical failure. - - - - - EBM rating: C-4
Vortex critical behavior at the de-confinement phase transition
The de-confinement phase transition in SU(2) Yang-Mills theory is revisited
in the vortex picture. Defining the world sheets of the confining vortices by
maximal center projection, the percolation properties of the vortex lines in
the hypercube consisting of the time axis and two spatial axis are studied.
Using the percolation cumulant, the temperature for the percolation transition
is seen to be in good agreement with the critical temperature of the thermal
transition. The finite size scaling function for the cumulant is obtained. The
critical index of the finite size scaling function is consistent with the index
of the 3D Ising model.Comment: 4 pages, 4 PS figures, using revtex4, paragraph and refs added, typo
correcte
Therapy preferences of patients with lung and colon cancer: A discrete choice experiment
Objectives: There is increasing interest in studies that examine patient preferences to measure health-related outcomes. Understanding patients’ preferences can improve the treatment process and is particularly relevant for oncology. In this study, we aimed to identify the subgroup-specific treatment preferences of German patients with lung cancer (LC) or colorectal cancer (CRC). Methods: Six discrete choice experiment (DCE) attributes were established on the basis of a systematic literature review and qualitative interviews. The DCE analyses comprised generalized linear mixed-effects model and latent class mixed logit model. Results: The study cohort comprised 310 patients (194 with LC, 108 with CRC, 8 with both types of cancer) with a median age of 63 (SD =10.66) years. The generalized linear mixed-effects model showed a significant (P<0.05) degree of association for all of the tested attributes. “Strongly increased life expectancy” was the attribute given the greatest weight by all patient groups. Using latent class mixed logit model analysis, we identified three classes of patients. Patients who were better informed tended to prefer a more balanced relationship between length and health-related quality of life (HRQoL) than those who were less informed. Class 2 (LC patients with low HRQoL who had undergone surgery) gave a very strong weighting to increased length of life. We deduced from Class 3 patients that those with a relatively good life expectancy (CRC compared with LC) gave a greater weight to moderate effects on HRQoL than to a longer life. Conclusion: Overall survival was the most important attribute of therapy for patients with LC or CRC. Differences in treatment preferences between subgroups should be considered in regard to treatment and development of guidelines. Patients’ preferences were not affected by sex or age, but were affected by the cancer type, HRQoL, surgery status, and the main source of information on the disease
Processing Succinct Matrices and Vectors
We study the complexity of algorithmic problems for matrices that are
represented by multi-terminal decision diagrams (MTDD). These are a variant of
ordered decision diagrams, where the terminal nodes are labeled with arbitrary
elements of a semiring (instead of 0 and 1). A simple example shows that the
product of two MTDD-represented matrices cannot be represented by an MTDD of
polynomial size. To overcome this deficiency, we extended MTDDs to MTDD_+ by
allowing componentwise symbolic addition of variables (of the same dimension)
in rules. It is shown that accessing an entry, equality checking, matrix
multiplication, and other basic matrix operations can be solved in polynomial
time for MTDD_+-represented matrices. On the other hand, testing whether the
determinant of a MTDD-represented matrix vanishes PSPACE$-complete, and the
same problem is NP-complete for MTDD_+-represented diagonal matrices. Computing
a specific entry in a product of MTDD-represented matrices is #P-complete.Comment: An extended abstract of this paper will appear in the Proceedings of
CSR 201
First Observation of a Stable Highly Dissipative Divertor Plasma Regime on the Wendelstein 7-X Stellarator
On practical problems to compute the ghost propagator in SU(2) lattice gauge theory
In SU(2) lattice pure gauge theory we study numerically the dependence of the
ghost propagator G(p) on the choice of Gribov copies in Lorentz (or Landau)
gauge. We find that the effect of Gribov copies is essential in the scaling
window region, however, it tends to decrease with increasing beta. On the other
hand, we find that at larger beta-values very strong fluctuations appear which
can make problematic the calculation of the ghost propagator.Comment: 15 pages, 5 postscript figures. 2 Figures added Revised version as to
be published in Phys.Rev.
Daily torpor: When heart and brain go cold - Nonlinear cardiac dynamics in the seasonal heterothermic Djungarian hamster
Djungarian hamsters (Phodopus sungorus) acclimated to short photoperiod display episodes of spontaneous daily torpor with metabolic rate depressed by ∼70%, body temperature (
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