1,344 research outputs found
PHP104 THE BUDGET IMPACT OF ORAL NUTRITIONAL SUPPLEMENTS IN THE COMMUNITY SETTING IN THE NETHERLANDS
Ernährungssicherung durch Ökologischen Landbau am Beispiel der Region Mostviertel- Eisenwurzen
Ein nachhaltiges Agrar- und Ernährungssystem verfolgt zumindest zwei Ziele: Bereitstellung hochwertiger Lebensmittel und Gewährleistung gesunder Ernährung bei gleichzeitiger größtmöglicher Schonung natürlicher Ressourcen. Zur komplementären Erreichung beider Zielsetzungen wird der Ökologische Landbau als Lösungsmodell diskutiert. Ziel der vorliegenden Arbeit ist es, am Beispiel der Region Mostviertel-Eisenwurzen (A) die Folgen einer großflächigen Umstellung für die Lebensmittelproduktionsmengen abzuschätzen. Darüber hinaus soll auf Seiten des Bedarfs eine konkrete Alternative in Form veränderter Verzehrsgewohnheiten entwickelt und deren Rückwirkung auf die Produktion bewertet werden
Auswirkungen acker- und pflanzenbaulicher Massnahmen auf die arbuskuläre Mykorrhiza im Ökologischen Landbau
Der oekologische Landbau laesst aufgrund der systemeigenen spezifischen Fruchtfolgen, Duengemassnahmen und Bodenbearbeitung positive Auswirkungen auf die Entwicklung d arbuskulaeren Mykorrhiza und die Kolonisierung der Kulturpflanzen erwarten. Diese positiven Auswirkungen wurden in vergleichenden Untersuchungen ueber die Auswirkungen einzelner Kulturmassnahmen auf die arbuskulaere Mykorrhiza in konventionell und nachhaltig bewirtschafteten Standorten nachgewiesen. Wenn in der Zukunft eine Verringerung des Eintrages an Agrochemikalien in die Kulturlandschaften angestrebt wird, muss der Bedeutung der arbuskulaeren Mykorrhiza eine hoehere Aufmerksamkeit gewidmet werden. Um die positiven Auswirkungen der arbuskulaeren Mykorrhiza in landwirtschaftlichen Produktionssystemen optimal zu nutzen, ist die Verwendung von geeigneten Duengemitteln in adaequater Menge, ein groesstmoeglicher Verzicht auf einen Pestizideinsatz und eine entsprechende Fruchtfolgegestaltung mit einem Minimum an Bodenbearbeitung und der Vermeidung von Schwarzbrache sicherzustellen. Ziel dieses Projektes ist die Optimierung der Lebensbedingungen und Leistungen der arbuskulaeren Mykorrhiza im oekologischen Landbau zur Optimierung des Pflanzenwachstums und der Sicherung der Ertraege. Dabei wird im Rahmen von Feldversuchen der Einfluss von acker- und pflanzenbaulichen Massnahmen (Fruchtfolge, Duengung, Bodenbearbeitung) sowie der Dauer der oekologischen Bewirtschaftung auf die arbuskulaere Mykorrhiza untersucht
When the optimal is not the best: parameter estimation in complex biological models
Background: The vast computational resources that became available during the
past decade enabled the development and simulation of increasingly complex
mathematical models of cancer growth. These models typically involve many free
parameters whose determination is a substantial obstacle to model development.
Direct measurement of biochemical parameters in vivo is often difficult and
sometimes impracticable, while fitting them under data-poor conditions may
result in biologically implausible values.
Results: We discuss different methodological approaches to estimate
parameters in complex biological models. We make use of the high computational
power of the Blue Gene technology to perform an extensive study of the
parameter space in a model of avascular tumor growth. We explicitly show that
the landscape of the cost function used to optimize the model to the data has a
very rugged surface in parameter space. This cost function has many local
minima with unrealistic solutions, including the global minimum corresponding
to the best fit.
Conclusions: The case studied in this paper shows one example in which model
parameters that optimally fit the data are not necessarily the best ones from a
biological point of view. To avoid force-fitting a model to a dataset, we
propose that the best model parameters should be found by choosing, among
suboptimal parameters, those that match criteria other than the ones used to
fit the model. We also conclude that the model, data and optimization approach
form a new complex system, and point to the need of a theory that addresses
this problem more generally
Auswirkungen unterschiedlicher Düngungssysteme im Ökologischen Landbau auf Bodenparameter und Entwicklung der Pflanzen
Auf dem landwirtschaftlichen Betrieb Rutzendorf soll ein umfassendes Langzeitmonitoring zur Entwicklung des biologischen Landbaus eingerichtet werden. Ein wissenschaftliches Konzepts soll erarbeitet und zum Teil schon umgesetzt werden. Die Wirkungen der Umstellung auf Ökologischen Landbau auf Boden, Wasser, Flora und Fauna soll anhand ausgewählter Eigenschaften erfasst werden. Entsprechend der Konzeption des Betriebs (vgl. ¿Konzept Biobetrieb Rutzendorf¿, Bericht an das BMLFUW, IfÖL, BOKU, März 2002) sollen drei Düngungsvarianten verglichen werden. Die Bedeutung verschiedener vorhandener Biotope (Gehölzstreifen, Hecken, ...) soll charakterisiert und neue, ergänzende Biotope geplant und angelegt werden. Versuchsort und -gegenstand ist der landwirtschaftliche Betrieb Rutzendorf der Bundesversuchswirtschaft Ges.m.b.H. Durchgeführt wird ein Monitoring der Auswirkungen von Düngungsvarianten unter Beibehaltung der Fruchtfolge sowie der Umstellung des Betriebes auf die Umwelt, Produktion und Wirtschaftlichkei
Monitoring der Umstellung auf den Ökologischen Landbau
A long term field monitoring concerning the development of organic farming is performed at the bio-farm "Rutzendorf" of the BVW GmbH in the Marchfeld region East of Vienna. It is an interdisciplinary project of eleven scientific institutes which started in 2003. The aims of the project are: examination of changes concerning soil and plant parameters with the conversion to organic farming; investigation of the effects of different organic fertilisation systems (green manure, communal green forage compost, farmyard manure) on soil properties and on the development of crops; analysis of existing biotops (hedges and field stripes) on the farm and planning and selective realization of new biotops with the aim of enhancing the biodiversity of the area
An HST Search for Lyman Continuum Emission From Galaxies at z=1.1--1.4
If enough of their Lyman limit continuum escapes, star-forming galaxies could
be significant contributors to the cosmic background of ionizing photons. To
investigate this possibility, we obtained the first deep imaging in the far
ultraviolet of eleven bright blue galaxies at intermediate redshift
(z=1.1--1.4). NO Lyman continuum emission was detected. Sensitive,
model-independent, upper limits of typically 2 x 10**-19 erg/sec/cm2/Ang were
obtained for the ionizing flux escaping from these normal galaxies. This
corresponds to lower limits on the observed ratio of 1500 to 700Ang flux of 150
up to 1000. Based on a wide range of stellar synthesis models, this suggests
that less than 6%, down to less than 1%, of the available ionizing flux emitted
by hot stars is escaping these galaxies. The magnitude of this spectral break
at the Lyman l imit confirms that the basic premise of `Lyman break' searches
for galaxies at high redshift can also be applied at intermediate redshifts.
This implies that the integrated contribution of galaxies to the UV cosmic
background at z around 1.2 is less than 15%, and may be less than 2%.Comment: 20 manuscript pages, which includes two tables and two figures. To be
published in 1 December 2003 issue of The Astrophysical Journa
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Enrollment of adolescents and young adults onto SWOG cancer research network clinical trials: A comparative analysis by treatment site and era.
BackgroundFew adolescents and young adults (AYAs, 15-39 years old) enroll onto cancer clinical trials, which hinders research otherwise having the potential to improve outcomes in this unique population. Prior studies have reported that AYAs are more likely to receive cancer care in community settings. The National Cancer Institute (NCI) has led efforts to increase trial enrollment through its network of NCI-designated cancer centers (NCICC) combined with community outreach through its Community Clinical Oncology Program (CCOP; replaced by the NCI Community Oncology Research Program in 2014).MethodsUsing AYA proportional enrollment (the proportion of total enrollments who were AYAs) as the primary outcome, we examined enrollment of AYAs onto SWOG therapeutic trials at NCICC, CCOP, and non-NCICC/non-CCOP sites from 2004 to 2013 by type of site, study period (2004-08 vs 2009-13), and patient demographics.ResultsOverall, AYA proportional enrollment was 10.1%. AYA proportional enrollment decreased between 2004-2008 and 2009-2013 (13.1% vs 8.5%, P < .001), and was higher at NCICCs than at CCOPs and non-NCICC/non-CCOPs (14.1% vs 8.3% and 9.2%, respectively; P < .001). AYA proportional enrollment declined significantly at all three site types. Proportional enrollment of AYAs who were Black or Hispanic was significantly higher at NCICCs compared with CCOPs or non-NCICC/non-CCOPs (11.5% vs 8.8, P = .048 and 11.5% vs 8.6%, P = .03, respectively).ConclusionNot only did community sites enroll a lower proportion of AYAs onto cancer clinical trials, but AYA enrollment decreased in all study settings. Initiatives aimed at increasing AYA enrollment, particularly in the community setting with attention to minority status, are needed
preclinical evidence from C57BL/6 mice
Chemotherapy-induced central nervous system (CNS) neurotoxicity presents an
unmet medical need. Patients often report a cognitive decline in temporal
correlation to chemotherapy, particularly for hippocampus-dependent verbal and
visuo-spatial abilities. We treated adult C57Bl/6 mice with 12 × 20 mg kg−1
paclitaxel (PTX), mimicking clinical conditions of dose-dense chemotherapy,
followed by a pulse of bromodesoxyuridine (BrdU) to label dividing cells. In
this model, mice developed visuo-spatial memory impairments, and we measured
peak PTX concentrations in the hippocampus of 230 nm l−1, which was sevenfold
higher compared with the neocortex. Histologic analysis revealed a reduced
hippocampal cell proliferation. In vitro, we observed severe toxicity in
slowly proliferating neural stem cells (NSC) as well as human neuronal
progenitor cells after 2 h exposure to low nanomolar concentrations of PTX. In
comparison, mature post-mitotic hippocampal neurons and cell lines of
malignant cells were less vulnerable. In PTX-treated NSC, we observed an
increase of intracellular calcium levels, as well as an increased activity of
calpain- and caspase 3/7, suggesting a calcium-dependent mechanism. This cell
death pathway could be specifically inhibited with lithium, but not glycogen
synthase kinase 3 inhibitors, which protected NSC in vitro. In vivo,
preemptive treatment of mice with lithium prevented PTX-induced memory
deficits and abnormal adult hippocampal neurogenesis. In summary, we
identified a molecular pathomechanism, which invokes PTX-induced cytotoxicity
in NSC independent of cell cycle status. This pathway could be
pharmacologically inhibited with lithium without impairing paclitaxel’s
tubulin-dependent cytostatic mode of action, enabling a potential
translational clinical approach
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