6,390 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
Outcome of renal grafts after simultaneous kidney/ pancreas transplantation
Nineteen patients with endstage renal failure due to Type 1 (insulin-dependent) diabetes mellitus received simultaneous pancreas/kidney transplants using bladder drainage technique. Another group of 25 Type 1 diabetic patients received pancreas/kidney transplants by the duct occlusion technique. We observed a higher incidence of rejection episodes in the patients of the bladder drainage group than those in the duct occlusion group, 14 of 19 patients (74%) vs 7 of 25 (28%) respectively. Anti CD3 antibodies (Orthoclone, OKT3) as a part of induction treatment was used more often in the bladder drainage group (58%) than in the control group (20%)
Estudo preliminar do vermicomposto produzido a partir de lodo de esgoto doméstico e solo
O lodo de esgoto doméstico é um resíduo gerado durante os processos de tratamento de esgoto, podendo ser estabilizado por diversos processos químicos, físicos e biológicos. O lodo de esgoto estabilizado (biossólido) não possui um destino final adequado e gera diversos problemas no sentido de sua disposição final. Dentre os muitos processos que visam à disposição do biossólido, destaca-se a reciclagem agrícola. A utilização da vermicompostagem como meio de estabilização do lodo de esgoto mostra-se como uma ferramenta útil na estabilização deste resíduo. O processo de vermicompostagem apresentou características físico-químicas satisfatórias para ser utilizado como técnica de estabilização do lodo de esgoto doméstico. O produto final apresentou potencial para ser utilizado na agricultura como fertilizante ou condicionador de solos.Domestic waste, a residue generated during sewage treatments, can be stabilized by many chemical, physical and biological processes. However, the stabilized waste (biosoil) currently lacks proper disposal alternatives. A new and promising disposal method is called farm recycling. The use of vermicomposting has shown to be useful as a mean to stabilize domestic waste. The biosoil achieved through this method exhibits high humidity-retaining capacity, good C/N relationship, as well as a satisfactory percentage of humic acid, thus being able to be incorporated into the soil as a conditioner and fertilizer
Quality of life in Type 1 (insulin-dependent) diabetic patients prior to and after pancreas and kidney transplantation in relation to organ function
Improvement of the quality of life in Type 1 (insulin-dependent) diabetic patients with severe late complications is one of the main goals of pancreas and/or kidney grafting. To assess the influences of these treatment modalities on the different aspects of the quality of life a cross-sectional study in 157 patients was conducted. They were categorized into patients pre-transplant without dialysis (n=29; Group A), pre-transplant under dialysis (n=44; Group B), post-transplant with pancreas and kidney functioning (n=31; Group C), post-transplant with functioning kidney, but insulin therapy (n=29; Group D), post-transplant under dialysis and insulin therapy again (n=15; Group E) and patients after single pancreas transplantation and rejection, with good renal function, but insulin therapy (n=9; Group F). All patients answered a mailed, self-administered questionnaire (217 questions) consisting of a broad spectrum of rehabilitation criteria. The results indicate a better quality of life in Groups C and D as compared to the other groups. In general the scores are highest in C, but without any significant difference to D. Impressive significant differences between C or D and the other groups were found especially in their satisfaction with physical capacity, leisure-time activities or the overall quality of life. The satisfaction with the latter is highest in C (mean±SEM: 4.0±0.2 on a 1 to 5-rating scale; significantly different from A: 3.1±0.1, B: 2.7±0.2 and E: 2.6±0.3; p<0.01), followed by D (3.8±0.2; significantly different from B and E; p<0.01). Group F shows a mean of 3.1±0.4, which is not significantly different from C. The percentages of patients in each group, who are not working: A: 38 %, B: 64 %, C: 74 %, D: 66 %, E: 87 % and F: 78 % indicate that there is no marked improvement in the vocational situation after successful grafting
Well-posedness of minimal time problems with constant dynamics in Banach spaces
This paper concerns the study of a general minimal time problem with a
convex constant dynamics and a closed target set in Banach spaces. We pay the main
attention to deriving sufficient conditions for the major well-posedness properties that include the existence and uniqueness of optimal solutions as well as certain regularity of the optimal value function with respect to state variables. Most of the results obtained are new even in finite-dimensional spaces. Our approach is based on advanced tools of variational analysis and generalized differentiation
Опухоли с невыявленным первичным очагом: современные подходы к лечению
Представлены современные методы и схемы лечения разных видов рака с невыясненным очагом и получаемые результаты.Contemporary methods of treatment of various types of cancer with unrevealed focus as well as the obtained results are described
Double Spin Asymmetries A_NN and A_SS at sqrt{s}=200 GeV in Polarized Proton-Proton Elastic Scattering at RHIC
We present the first measurements of the double spin asymmetries A_NN and
A_SS at sqrt{s}=200 GeV, obtained by the pp2pp experiment using polarized
proton beams at the Relativistic Heavy Ion Collider (RHIC). The data were
collected in the four momentum transfer t range 0.01<|t|<0.03 (GeV/c)^2. The
measured asymmetries, which are consistent with zero, allow us to estimate
upper limits on the double helicity-flip amplitudes phi_2 and phi_4 at small t
as well as on the difference Delta(sigma_T) between the total cross sections
for transversely polarized protons with antiparallel or parallel spin
orientations.Comment: 13 pages with 3 figures. Final version accepted by Phys. Lett.
Exciton swapping in a twisted graphene bilayer as a solid-state realization of a two-brane model
It is shown that exciton swapping between two graphene sheets may occur under
specific conditions. A magnetically tunable optical filter is described to
demonstrate this new effect. Mathematically, it is shown that two turbostratic
graphene layers can be described as a "noncommutative" two-sheeted
(2+1)-spacetime thanks to a formalism previously introduced for the study of
braneworlds in high energy physics. The Hamiltonian of the model contains a
coupling term connecting the two layers which is similar to the coupling
existing between two braneworlds at a quantum level. In the present case, this
term is related to a K-K' intervalley coupling. In addition, the experimental
observation of this effect could be a way to assess the relevance of some
theoretical concepts of the braneworld hypothesis.Comment: 15 pages, 3 figures, final version published in European Physical
Journal
The impact of spectral resolution on satellite retrieval accuracy of CO_2 and CH_4
The Fourier-transform spectrometer on board the Japanese GOSAT (Greenhouse gases Observing SATellite) satellite offers an excellent opportunity to study the impact of instrument resolution on retrieval accuracy of CO_2 and CH_4. This is relevant to further improve retrieval accuracy and to optimize the cost–benefit ratio of future satellite missions for the remote sensing of greenhouse gases. To address this question, we degrade GOSAT measurements with a spectral resolution of ≈ 0.24 cm^(−1) step by step to a resolution of 1.5 cm^(−1). We examine the results by comparing relative differences at various resolutions, by referring the results to reference values from the Total Carbon Column Observing Network (TCCON), and by calculating and inverting synthetic spectra for which the true CO_2 and CH_4 columns are known. The main impacts of degrading the spectral resolution are reproduced for all approaches based on GOSAT measurements; pure forward model errors identified with simulated measurements are much smaller.
For GOSAT spectra, the most notable effect on CO_2 retrieval accuracy is the increase of the standard deviation of retrieval errors from 0.7 to 1.0% when the spectral resolution is reduced by a factor of six. The retrieval biases against atmospheric water abundance and air mass become stronger with decreasing resolution. The error scatter increase for CH_4 columns is less pronounced. The selective degradation of single spectral windows demonstrates that the retrieval accuracy of CO_2 and CH_4 is dominated by the spectral range where the absorption lines of the target molecule are located. For both GOSAT and synthetic measurements, retrieval accuracy decreases with lower spectral resolution for a given signal-to-noise ratio, suggesting increasing interference errors
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