420 research outputs found
The quality of life improvement in patients administered cytotoxic drugs as the result of new supportive methods of therapy application
In recent years new anti-emetic agents have been developed. These drugs greatly reduee or eliminate chemotherapy -related nausea and vomiting.Introduction of new drugs as G-CSF (Neupogen), rHuGM-CSF (Leucomax) and Eprex (rHu-EPO) gave the possibility to prevent serious chemotherapy side-effects like leucopenia and anaemia.Supportive treatment in cancer patients enormous influence the quality of life and reduce therapy- related anxiety.In our Oncological Clinic this supportive treatment has been used for 3 years allowing more aggresive therapy
Beyond convergence rates: Exact recovery with Tikhonov regularization with sparsity constraints
The Tikhonov regularization of linear ill-posed problems with an
penalty is considered. We recall results for linear convergence rates and
results on exact recovery of the support. Moreover, we derive conditions for
exact support recovery which are especially applicable in the case of ill-posed
problems, where other conditions, e.g. based on the so-called coherence or the
restricted isometry property are usually not applicable. The obtained results
also show that the regularized solutions do not only converge in the
-norm but also in the vector space (when considered as the
strict inductive limit of the spaces as tends to infinity).
Additionally, the relations between different conditions for exact support
recovery and linear convergence rates are investigated.
With an imaging example from digital holography the applicability of the
obtained results is illustrated, i.e. that one may check a priori if the
experimental setup guarantees exact recovery with Tikhonov regularization with
sparsity constraints
Accelerated photosynthesis routine in LPJmL4
The increasing impacts of climate change require strategies for climate adaptation. Dynamic global vegetation models (DGVMs) are one type of multi-sectorial impact model with which the effects of multiple interacting processes in the terrestrial biosphere under climate change can be studied.
The complexity of DGVMs is increasing as more and more processes, especially for plant physiology, are implemented. Therefore, there is a growing demand for increasing the computational performance of the underlying algorithms as well as ensuring their numerical accuracy. One way to approach this issue is to analyse the routines which have the potential for improved computational efficiency and/or increased accuracy when applying sophisticated mathematical methods.
In this paper, the FarquharâCollatz photosynthesis model under water stress as implemented in the LundâPotsdamâJena managed Land DGVM (4.0.002) was examined.
We additionally tested the uncertainty of most important parameter of photosynthesis as an additional approach to improve model quality. We found that the numerical solution of a nonlinear equation, so far solved with the bisection method, could be significantly improved by using Newton's method instead. The latter requires the computation of the derivative of the underlying function which is presented. Model simulations show a significantly lower number of iterations to solve the equation numerically and an overall run time
reduction of the model of about 16â% depending on the chosen accuracy.
Increasing the parameters Ξ and αC3 by 10â%, respectively, while keeping all other parameters at their original value, increased global gross primary production (GPP) by 2.384 and 9.542âGtCâyrâ1, respectively. The FarquharâCollatz photosynthesis model forms the core component in many DGVMs and land surface models. An update in the numerical solution of the nonlinear equation
in connection with adjusting globally important parameters to best known values can therefore be applied to similar photosynthesis models. Furthermore, this exercise can serve as an example for improving computationally costly routines while improving their mathematical accuracy.</p
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