1,160 research outputs found
Impact of different Agricultural Systems and Patterns of Consumption on Greenhouse-Gas Emissions in Austria
Agricultural systems as well as consumer patterns influence the green house gas emissions. Therefore, we analysed different farming systems, consumption patterns and seasonal oriented food consumption. Whereas conventional production and the current meat oriented nutrition patterns lead to high green house gas emissions, there is a tremendous reduction potential, if products are organically produced and if there is a shift to vegetarian-based diets.. Nevertheless, there is a need for research in terms of data quality, and a differentiation of farming systems as well as nutrition patterns
Potentials of Organic Farming in the Region of Marchfeld (Austria)
Marchfeld is one of the most important crop production regions in Austria. High input agriculture causes environmental problems, especially groundwater pollution by nitrate and pesticides, decline of soil fertility and ecosystem diversity. While Austria has about 8.3 % certified organic farms, Marchfeld has only 1.5 %. The presented study was carried out in order to investigate the potentials of organic farming for solving environmental problems. The main interest of this work is the present economic and social situation of organic agriculture, its environmental effects and the identification of factors that support or hamper the further increase of organic farming in this regio
Human Capacity Development for Income Generation and Organic Market Linkages in Uganda
Rapid economic growth in Uganda has resulted from the strong emphasis on the market liberalization policies tied to export promotion. Commercialization of smallholder farmers’ products has been at the heart of the country’s development program since the year 2000. This study describes how the organic farming sector links farmers to markets through community empowerment, resource development and market linkage intervention strategies using a qualitative analysis of the institutional support provided by the organic sector. The private sector assures technical commodity related support, organic export linkage, and higher incomes while the civil service society emphasizes facilitation to a wide range of market linkages and builds capacities along aspects of the market chain. They both contribute to the empowerment of the communities to make decisions on various aspects of their farm lives. Further studies to assess the impact of the respective farmer market interventions on the livelihoods of the rural population are required
Potenziale der biologischen Landwirtschaft zur Entlastung des Natur- und Landschaftshaushaltes im Marchfeld
Das Marchfeld unterliegt heute einer überwiegend intensiven landwirtschaftlichen Nutzung, die maßgeblich über eine konventionelle bzw. Integrierte Produktion erfolgt. Die unter ökonomischen Gesichtspunkten aus der Sicht der Landwirte erforderliche intensive Produktion wirkt sich belastend auf das Grundwasser (Stoffeintrag), die Bodenkrume (Erosion) und die Arten und Lebensraumvielfalt aus. Die Anwendung und Umsetzung der Prinzipien des ökologischen Landbaus lässt eine Reihe ökologischer Leistungen erwarten, die insbesondere auch zur Entlastung oben genannter, durch die Landwirtschaft verursachter Probleme im Marchfeld beitragen können
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Child Sexual Abuse Prevention Programs: What Makes Them Effective in Protecting Children?
Child sexual abuse prevention programs have proliferated over the past several years. Many of these program approaches, which include plays, games and videos, are visually appealing and highly entertaining, and parents and teachers have widely embraced them. However, despite the popularity of such programs, little effort has been made to evaluate their effectiveness in changing children's behavior. As a result of participation in a sexual abuse prevention program, has a child's vulnerability to abuse been reduced, for example, or has his or her sense of personal safety been enhanced
Investigating the prevalence and causes of prescribing errors in general practice : the PRACtICe Study
Report prepared by the University of Nottingham, University of Reading and University of Hertfordshir
Tumor growth instability and the onset of invasion
Motivated by experimental observations, we develop a mathematical model of
chemotactically directed tumor growth. We present an analytical study of the
model as well as a numerical one. The mathematical analysis shows that: (i)
tumor cell proliferation by itself cannot generate the invasive branching
behaviour observed experimentally, (ii) heterotype chemotaxis provides an
instability mechanism that leads to the onset of tumor invasion and (iii)
homotype chemotaxis does not provide such an instability mechanism but enhances
the mean speed of the tumor surface. The numerical results not only support the
assumptions needed to perform the mathematical analysis but they also provide
evidence of (i), (ii) and (iii). Finally, both the analytical study and the
numerical work agree with the experimental phenomena.Comment: 12 pages, 8 figures, revtex
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
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
The radio and IR counterparts of the ring nebula around HD211564
We report the detection of the radio and infrared counterparts of the ring
nebula around the WN3(h) star HD211564 (WR152), located to the southwest of the
HII region Sh2132. Using radio continuum data from the Canadian Galactic Plane
Survey, we identified the radio counterparts of the two concentric rings, of
about 9' and 16' in radius, related to the star. After applying a filling
factor f = 0.05-0.12, electron densities and ionized masses are in the range
10-16 cm^-3 and 450-700 Mo, respectively. The analysis of the HI gas emission
distribution allowed the identification of 5900 Mo of neutral atomic gas with
velocities between -52 and -43 km/s probably linked to the nebula. The region
of the nebula is almost free of molecular gas. Only four small clumps were
detected, with a total molecular mass of 790 Mo. About 310 Mo are related to a
small infrared shell-like source linked to the inner ring, which is also
detected in the MSX band A. An IRAS YSO candidate is detected in coincidence
with the shell-like IR source.
We suggest that the optical nebula and its neutral counterparts originated
from the stellar winds from the WR star and its massive progenitor, and are
evolving in the envelope of a slowly expanding shell centered at (l,b) = (102
30, -0 50), of about 31 pc in radius. The bubble's energy conversion efficiency
is in agreement with recent numerical analysis and with observational results.Comment: 11 pages, 7 figures, accepted in MNRA
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