486 research outputs found
Pak door met natuurinclusieve landbouw
No full textAls we op de huidige manier door blijven gaan met het agrarisch natuurbeheer, zal de natuur er te weinig mee opschieten. En is alle moeite voor niets. Hoogleraar ‘Beheer van biodiversiteit en agrarisch landschap’ Hens Runhaar pleit daarom voor natuurinclusieve landbouw, maar wel eentje die niet meer vrijblijvend is. En met een royale beloning voor de boeren en veel minder bureaucratie
Pak door met natuurinclusieve landbouw
No full textAls we op de huidige manier door blijven gaan met het agrarisch natuurbeheer, zal de natuur er te weinig mee opschieten. En is alle moeite voor niets. Hoogleraar ‘Beheer van biodiversiteit en agrarisch landschap’ Hens Runhaar pleit daarom voor natuurinclusieve landbouw, maar wel eentje die niet meer vrijblijvend is. En met een royale beloning voor de boeren en veel minder bureaucratie
Data for: The effectiveness of Environmental Assessment in Flanders
No full textSupplementary materia
The effect of optimized lighting conditions on feather pecking and production of laying hens
No full textFeather pecking is one of the major problems in commercially kept laying hens. The current research considers the relevance of colour of light in the feather pecking problem
Reinforcer magnitude and demand under fixed-ratio schedules with domestic hens
No full textThis study compared three methods of normalizing demand functions to allow comparison of demand for different commodities and examined how varying reinforcer magnitudes affected these analyses. Hens responded under fixed-ratio schedules in 40-min sessions with response requirement doubling each session and with 2-s, 8-s, and 12-s access to wheat. Over the smaller fixed ratios overall response rates generally increased and were higher the shorter the magazine duration. The logarithms of the number of reinforcers obtained (consumption) and the fixed ratio (price) were well fitted by curvilinear demand functions (Hursh et al., 1988. Journal of the Experimental Analysis of Behavior 50, 419–440) that were inelastic (b negative) over small fixed-ratios. The fixed ratio with maximal response rate (Pmax) increased, and the rate of change of elasticity (a) and initial consumption (L) decreased with increased magazine duration. Normalizing consumption using measures of preference for various magazine durations (3-s vs. 3-s, 2-s vs. 8-s, and 2-s vs. 12-s), obtained using concurrent schedules, gave useful results as it removed the differences in L. Normalizing consumption and price (Hursh and Winger, 1995. Journal of the Experimental Analysis of Behavior 64, 373–384) unified the data functions as intended by that analysis. The exponential function (Hursh and Silberberg, 2008. Psychological Review, 115, 186–198) gave an essential value that increased (i.e., α decreased significantly) as magazine duration decreased. This was not as predicted, since α should be constant over variations in magazine duration, but is similar to previous findings using a similar procedure with different food qualities (hens) and food quantities (rats)
On the necessity of connectivity: linking key characteristics of environmental problems with governance modes
No full textEnvironmental problems are often multi-faceted and complex by nature, consisting of diverse, intertwined dimensions. In this article, we argue that environmental problem characteristics have consequences for the selection of appropriate governance modes, and finally on policy effectiveness. We rely on an in-depth literature review to proceed in two steps. First, we outline three key environmental problem characteristics: uncertainties, cause–effect mismatches and norm plurality. We then outline six different governance modes capable of producing policies and solutions to tackle challenges arising from the three problem characteristics. Next, through empirical illustrations, we demonstrate the relevance of linking governance modes to these characteristics via the introduction and articulation of the concept of ‘connectivity’, i.e., linking actors, issues, sectors and scale levels towards realizing effective policy solutions for complex environmental problems
Efficient Pricing in Transport
No full textThe Gap between Theory and Practice
Many transport economists agree on the need for ‘efficient pricing’ in transport, as this would improve allocative efficiency and raise social welfare. Although the principle of efficient pricing is gaining ground in many countries, up to now it has been applied only rarely because of strong social resistance. But how can so many people be opposed to a principle which aims to increase social welfare? In this paper, I explore the major reasons underlying this paradox and examine the validity of arguments for and against efficient pricing. It appears that most arguments against efficient pricing can be refuted easily. However, everything stands or falls on the basic assumption that efficient pricing will increase social welfare, the validity of which appears to be practically impossible to prove. The main cause of this difficulty is the lack of complete information on the welfare effects of efficient pricing
Efficient pricing in transport: the gap between theory and practice
No full textMany transport economists agree on the need for ‘efficient pricing’ in transport, as this
would improve allocative efficiency and raise social welfare. Although the principle of
efficient pricing is gaining ground in many countries, up to now it has been applied only
rarely because of strong social resistance. But how can so many people be opposed to a
principle which aims to increase social welfare? In this paper, I explore the major reasons
underlying this paradox and examine the validity of arguments for and against efficient
pricing. It appears that most arguments against efficient pricing can be refuted easily.
However, everything stands or falls on the basic assumption that efficient pricing will
increase social welfare, the validity of which appears to be practically impossible to prove.
The main cause of this difficulty is the lack of complete information on the welfare effects of
efficient pricing
Immunomodulation by diet : individual differences in sensitivity in layer hens
No full textEnhancing relevant immunity of production animals to achieve more robust animals is receiving more and more attention. Several epidemics have hit production animals recently and with devastating consequences, but enhancing diseases resistance increasingly provides new opportunities. Furthermore, welfare and health of production animals is becoming a more and more consumer driven topic. Several routes are being used to approach the possibility of enhancing immunity such as selective breeding, enriched and altered housing conditions, vaccination programs, diet supplementation with immune stimulating components, and other management procedures. Disease susceptibility has been shown to be related to stress reactivity, which in turn is related to differences in HPA axis reactivity. Interestingly, independent of selection criteria used, the extremes of various selection procedures result in a recurrent dichotomy in HPA axis reactivity, either being hyperresponsive or hyporesponsive to stress. Animals with a hyperresponsive HPA axis show greater environmental sensitivity, while the hyporeactive animals are more intrinsically regulated. Often, research on immunomodulation is performed with compromised animals and/or exaggerated supplementation of dietary components in one generation of animals, but epigenetics by definition seems to be the mechanism for mothers to prepare their offspring for the environment they will be born into. Enhancing immunity through normal diet in uncompromised animals is rarely investigated, let alone over generations. In this thesis the aim was to induce immunomodulation through diet in selection lines of chicken that have previously been selected on their antibody response to sheep red blood cells over two generations of chicken. First, potential HPA axis differences were examined in these selection lines to establish their environmental sensitivity, whereafter immunomodulation through normal diet was investigated in humoral and cellular parameters of immunity. As humoral immunocompentence was not easily modulated, an immune trigger was used to detect potential differences in humoral reactivity. The selection lines showed differential sensitivity to immunomodulation by diet in both generations, suggesting that adaptation to environmental factors may be a line-specific (genetically based) process, with differential neuroendocrine regulation. Most interestingly, the second generation showed effects of the diets in all the selection lines, albeit in different manners. It is concluded that normal diet can cause immunomodulation, mainly in animals with hyper HPA axis reactivity, and that introducing such practices may be more beneficial when mothers are treated, as all offspring showed immunomodulation, irrespective of selection line. While genetic background and/or epigenetic processes on neuroendocrine and immune regulation of the individual form the framework wherein individual immunomodulation by diet can take place, environmental conditions determine if the modulation is beneficial or not. <br/
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