282 research outputs found
Form and function in hillslope hydrology : in situ imaging and characterization of flow-relevant structures
Thanks to Elly Karle and the Engler-BunteInstitute, KIT, for the IC measurements of bromide. We are grateful to Selina Baldauf, Marcel Delock, Razije Fiden, Barbara Herbstritt, Lisei Köhn, Jonas Lanz, Francois Nyobeu, Marvin Reich and Begona Lorente Sistiaga for their support in the lab and during fieldwork, as well as Markus Morgner and Jean Francois Iffly for technical support and Britta Kattenstroth for hydrometeorological data acquisition. Laurent Pfister and Jean-Francois Iffly from the Luxembourg Institute of Science and Technology (LIST) are acknowledged for organizing the permissions for the experiments. Moreover, we thank Markus Weiler (University of Freiburg) for his strong support during the planning of the hillslope experiment and the preparation of the manuscript. This study is part of the DFG-funded CAOS project âFrom Catchments as Organised Systems to Models based on Dynamic Functional Unitsâ (FOR 1598). The manuscript was substantially improved based on the critical and constructive comments of the anonymous reviewers, Christian Stamm and Alexander Zimmermann, and the editor Ross Woods during the open review process, which is highly appreciated.Peer reviewedPublisher PD
Form and function in hillslope hydrology : Characterization of subsurface ow based on response observations
Acknowledgements. We are grateful to Marcel Delock, Lisei Köhn, and Marvin Reich for their support during fieldwork, as well as Markus Morgner and Jean Francois Iffly for technical support, Britta Kattenstroth for hydrometeorological data acquisition and isotope sampling, and Barbara Herbstritt and Begoña Lorente Sistiaga for laboratory work. Laurent Pfister and Jean-Francois Iffly from the Luxembourg Institute of Science and Technology (LIST) are acknowledged for organizing the permissions for the experiments and providing discharge data for Weierbach 1 and Colpach. We also want to thank Frauke K. Barthold and the two anonymous reviewers, whose thorough remarks greatly helped to improve the manuscript. This study is part of DFG-funded CAOS project âFrom Catchments as Organised Systems to Models based on Dynamic Functional Unitsâ (FOR 1598). The article processing charges for this open-access publication were covered by a Research Centre of the Helmholtz Association.Peer reviewedPublisher PD
Picturing and modeling catchments by representative hillslopes
This study explores the suitability of a single hillslope as a parsimonious representation of a catchment in a physically based model. We test this hypothesis by picturing two distinctly different catchments in perceptual models and translating these pictures into parametric setups of 2-D physically based hillslope models. The model parametrizations are based on a comprehensive field data set, expert knowledge and process-based reasoning. Evaluation against streamflow data highlights that both models predicted the annual pattern of streamflow generation as well as the hydrographs acceptably. However, a look beyond performance measures revealed deficiencies in streamflow simulations during the summer season and during individual rainfallârunoff events as well as a mismatch between observed and simulated soil water dynamics. Some of these shortcomings can be related to our perception of the systems and to the chosen hydrological model, while others point to limitations of the representative hillslope concept itself. Nevertheless, our results confirm that representative hillslope models are a suitable tool to assess the importance of different data sources as well as to challenge our perception of the dominant hydrological processes we want to represent therein. Consequently, these models are a promising step forward in the search for the optimal representation of catchments in physically based models
High efficacy and low toxicity of weekly docetaxel given as first-line treatment for metastatic breast cancer
Background: Docetaxel is one of the most effective antitumor agents currently available for the treatment of metastatic breast cancer (MBC). This phase II multicenter study prospectively analyzed the efficacy and toxicity of docetaxel given on a weekly schedule as first-line treatment of metastatic breast cancer. Patients and Methods: All patients received docetaxel, 35 mg/m(2) weekly for 6 weeks, followed by 2 weeks of rest. Subsequent cycles ( 3 weeks of treatment, 2 weeks of rest) were given until a maximum of 5 cycles or disease progression. Premedication consisted of 8 mg dexamethasone intravenously 30 min prior to the infusion of docetaxel. Results: Fifty-four patients at a median age of 58 years with previously untreated MBC were included in the study. A median of 10 doses ( median cumulative dose 339 mg/m(2)) was administered ( range: 2 - 18). The overall response rate was 48.1% ( 95% CI: 34 - 61%, intent-to-treat). Median survival was 15.8 months and median time to progression was 5.9 months ( intent-to-treat). Hematological toxicity was mild with absence of neutropenia-related complications. Grade 3 neutropenia was observed in 3.7% of patients and grade 3 and 4 anemia was observed in 5.6 and 1.9% of patients, respectively. Conclusion: The weekly administration of docetaxel is highly efficient and safe as first-line treatment for MBC and may serve as an important treatment option specifically in elderly patients and patients with a reduced performance status. Copyright (C) 2005 S. Karger AG, Basel
Soil water retention and hydraulic conductivity measured in a wide saturation range
Soil hydraulic properties (SHPs), particularly soil water retention
capacity and hydraulic conductivity of unsaturated soils, are among the key
properties that determine the hydrological functioning of terrestrial
systems. Some large collections of SHPs, such as the UNSODA and HYPRES
databases, have already existed for more than 2 decades. They have provided an
essential basis for many studies related to the critical zone. Today,
sample-based SHPs can be determined in a wider saturation range and with
higher resolution by combining some recently developed laboratory methods.
We provide 572 high-quality SHP data sets from undisturbed, mostly central
European samples covering a wide range of soil texture, bulk density and
organic carbon content. A consistent and rigorous quality filtering ensures
that only trustworthy data sets are included. The data collection contains
(i)Â SHP data, which consist of soil water retention and hydraulic conductivity data,
determined by the evaporation method and supplemented by retention data
obtained by the dewpoint method and saturated conductivity measurements;
(ii)Â basic soil data, which consist of particle size distribution determined by sedimentation
analysis and wet sieving, bulk density and organic carbon content; and (iii)Â metadata, which include the coordinates of the sampling locations. In
addition, for each data set, we provide soil hydraulic parameters for the
widely used van GenuchtenâMualem model and for the more advanced
PetersâDurnerâIden model. The data were originally collected to develop and
test SHP models and associated pedotransfer functions. However, we expect
that they will be very valuable for various other purposes such as
simulation studies or correlation analyses of different soil properties to
study their causal relationships. The data are available at
https://doi.org/10.5880/fidgeo.2023.012 (Hohenbrink et al.,
2023).</p
HESS Opinions: Functional units: a novel framework to explore the link between spatial organization and hydrological functioning of intermediate scale catchments
This opinion paper proposes a novel framework for exploring how spatial organization alongside
with spatial heterogeneity controls functioning of intermediate scale catchments of organized
complexity. Key idea is that spatial organization in landscapes implies that functioning of
intermediate scale catchments is controlled by a hierarchy of functional units: hillslope scale
lead topologies and embedded elementary functional units (EFUs). We argue that similar soils and
vegetation communities and thus also soil structures "co-developed" within EFUs in an adaptive,
self-organizing manner as they have been exposed to similar flows of energy, water and nutrients
from the past to the present. Class members of the same EFU (class) are thus deemed to belong to
the same ensemble with respect to controls of the energy balance and related vertical flows of
capillary bounded soil water and heat. Class members of superordinate lead topologies are
characterized by the same spatially organized arrangement of EFUs along the gradient driving
lateral flows of free water as well as a similar surface and bedrock topography. We hence
postulate that they belong to the same ensemble with respect to controls on rainfall runoff
transformation and related vertical and lateral fluxes of free water. We expect class members of
these functional units to have a distinct way how their architecture controls the interplay of
state dynamics and integral flows, which is typical for all members of one class but dissimilar
among the classes. This implies that we might infer on the typical dynamic behavior of the most
important classes of EFU and lead topologies in a catchment, by thoroughly characterizing a few
members of each class. A major asset of the proposed framework, which steps beyond the concept of
hydrological response units, is that it can be tested experimentally. In this respect, we reflect
on suitable strategies based on stratified observations drawing from process hydrology, soil
physics, geophysics, ecology and remote sensing which are currently conducted in replicates of
candidate functional units in the Attert basin (Luxembourg), to search for typical and similar
functional and structural characteristics. A second asset of this framework is that it blueprints
a way towards a structurally more adequate model concept for water and energy cycles in
intermediate scale catchments, which balances necessary complexity with falsifiability. This is
because EFU and lead topologies are deemed to mark a hierarchy of "scale breaks" where
simplicity with respect to the energy balance and stream flow generation emerges from spatially organized
process-structure interactions. This offers the opportunity for simplified descriptions of these
processes that are nevertheless physically and thermodynamically consistent. In this respect we
reflect on a candidate model structure that (a) may accommodate distributed observations of states
and especially terrestrial controls on driving gradients to constrain the space of feasible model
structures and (b) allows testing the possible added value of organizing principles to understand
the role of spatial organization from an optimality perspective
Pegfilgrastimâ±âciprofloxacin for primary prophylaxis with TAC (docetaxel/doxorubicin/cyclophosphamide) chemotherapy for breast cancer. Results from the GEPARTRIO study
Background: TAC (docetaxel/doxorubicin/cyclophosphamide) is associated with high incidences of grade 4 neutropenia and febrile neutropenia (FN). This analysis compared the efficacies of four regimens for primary prophylaxis of FN and related toxic effects in breast cancer patients receiving neoadjuvant TAC. Patients and methods: Patients with stage T2-T4 primary breast cancer were scheduled to receive 6-8 cycles of TAC. Primary prophylaxis was: ciprofloxacin 500 mg orally twice daily on days 5-14 (nâ=â253 patients; 1478 cycles), daily granulocyte colony-stimulating factor (G-CSF) (filgrastim 5 ÎŒg/kg/day or lenograstim 150 ÎŒg/m2/day) on days 5-10 (nâ=â377; 2400 cycles), pegfilgrastim 6 mg on day 2 (nâ=â305; 1930 cycles), or pegfilgrastim plus ciprofloxacin (nâ=â321; 1890 cycles). Results: Pegfilgrastim with/without ciprofloxacin was significantly more effective than daily G-CSF or ciprofloxacin in preventing FN (5% and 7% versus 18% and 22% of patients; all Pâ<â0.001), grade 4 neutropenia, and leukopenia. Pegfilgrastim plus ciprofloxacin completely prevented first cycle FN (Pâ<â0.01 versus pegfilgrastim alone) and fatal neutropenic events. Conclusion: Ciprofloxacin alone, or daily G-CSF from day 5-10 (as in common practice), provided suboptimal protection against FN and related toxic effects in patients receiving TAC. Pegfilgrastim was significantly more effective in this setting, especially if given with ciprofloxaci
Picturing and modeling catchments by representative hillslopes
This study explores the suitability of a single hillslope as a parsimonious
representation of a catchment in a physically based model. We test this
hypothesis by picturing two distinctly different catchments in perceptual
models and translating these pictures into parametric setups of 2-D
physically based hillslope models. The model parametrizations are based on a
comprehensive field data set, expert knowledge and process-based reasoning.
Evaluation against streamflow data highlights that both models predicted the
annual pattern of streamflow generation as well as the hydrographs
acceptably. However, a look beyond performance measures revealed deficiencies
in streamflow simulations during the summer season and during individual
rainfall–runoff events as well as a mismatch between observed and simulated soil water dynamics. Some of these shortcomings can be related to our
perception of the systems and to the chosen hydrological model, while others
point to limitations of the representative hillslope concept itself.
Nevertheless, our results confirm that representative hillslope models are a
suitable tool to assess the importance of different data sources as well as
to challenge our perception of the dominant hydrological processes we want to
represent therein. Consequently, these models are a promising step forward in
the search for the optimal representation of catchments in physically based
models
Cardiac safety of adjuvant pegylated liposomal doxorubicin with concurrent trastuzumab: a randomized phase II trial
Background The cardiac safety of trastuzumab concurrent with pegylated liposomal doxorubicin (PLD) in an adjuvant breast cancer treatment regimen is unknown. Patients and methods Women with resected node-positive or intermediate-risk node-negative HER2 overexpressing breast cancer and baseline left ventricular ejection fraction (LVEF) â„55% were randomized (1:2) to doxorubicin 60 mg/m2 (A)+cyclophosphamide 600 mg/m2 (C) every 21 days (q21d) for four cycles or PLD 35 mg/m2+C q21d+trastuzumab 2 mg/kg weekly (H) for 12 weeks. Both groups then received paclitaxel (Taxol, T) 80 mg/m2 with H for 12 weeks followed by H to complete 1 year. The primary end point was cardiac event rate or inability to administer 1 year of trastuzumab. Results Of 181 randomized patients, 179 underwent cardiac analysis. The incidence of cardiac toxicity or inability to administer trastuzumab due to cardiotoxicity was 18.6% [n=11; 95% confidence interval (CI) 9.7% to 30.9%] with A+C â T+H and 4.2% (n=5; 95% CI 1.4% to 9.5%) with PLD+C+H â T+H (P=0.0036). All events, except one, were asymptomatic systolic dysfunction or mildly symptomatic heart failure. Mean absolute LVEF reduction at cycle 8 was greater with doxorubicin (5.6% versus 2.1%; P=0.0014). Conclusion PLD+C+H â T+H is feasible and results in lower early cardiotoxicity rates compared with A+C â T+
Soil moisture and matric potential-an open field comparison of sensor systems
Soil water content and matric potential are central hydrological state variables. A large variety of automated probes and sensor systems for state monitoring exist and are frequently applied. Most applications solely rely on the calibration by the manufacturers. Until now, there has been no commonly agreed-upon calibration procedure. Moreover, several opinions about the capabilities and reliabilities of specific sensing methods or sensor systems exist and compete. A consortium of several institutions conducted a comparison study of currently available sensor systems for soil water content and matric potential under field conditions. All probes were installed at 0.2mb.s. (metres below surface), following best-practice procedures. We present the set-up and the recorded data of 58 probes of 15 different systems measuring soil moisture and 50 further probes of 14 different systems for matric potential. We briefly discuss the limited coherence of the measurements in a cross-correlation analysis. The measuring campaign was conducted during the growing period of 2016. The monitoring data, results from pedophysical analyses of the soil and laboratory reference measurements for calibration are published in Jackisch et al. (2018, https://doi.org/10.1594/PANGAEA.892319)
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