Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Sensor based eating time variables of dairy cows in the transition periodrelated to the time to first service
Hut, P.R. ; Mulder, A. ; Broek, J. van den; Hulsen, Jan ; Hooijer, G.A. ; Stassen, E.N. ; Eerdenburg, F.J.C.M. van; Nielen, M. - \ 2019
Preventive Veterinary Medicine 169 (2019). - ISSN 0167-5877 - 8 p.
In dairy cattle, reproductive diseases and infertility are some of the most important reasons for culling, where postpartum negative energy balance (NEB) reduces reproductive performance. This single cohort observational study reports the association between eating time and the interval between calving and first service in 2036 dairy cows on 17 commercial farms in The Netherlands. Cows were equipped with a commercially available neck sensor (Nedap, Groenlo, The Netherlands), that measured the time cows spent eating, from 28 days (d) before until 28 d after parturition. Primiparous cows spent a mean of +45 minutes (min) eating time per day ante partum and +15 min eating time post partum more than multiparous cows. A Cox proportional hazard model was used to analyze eating time variables in relation to the interval between calving and first service. From 4 weeks before until 4 weeks after calving eating time variables per week were used. Weeks -4, -3 + 3 and +4 were used as weeks with stable eating time patterns and therefore the mean eating time per week and the standard deviation of the mean eating time per week were used. Weeks -2, -1, +1 and +2 were addressed as periods with unstable eating patterns and therefore the slope in eating time per week and the residual variance of the slope per week were modeled. Significant results were the mean eating time in week -4 and +3 where in both weeks higher eating time lead to a higher hazard for first service. Difference between primiparous and multiparous cows were also significant with a higher hazard for first service for primiparous cows. Week 4 post partum presented a significant difference between eating time of primiparous cows and multiparous cows. These results display how eating time variables in the transition period could be related to the interval between calving and first service, and that there is a relation between mean eating time in week -4, +3, +4 and the interval between calving and first insemination.
Flooded by jargon: how the interpretation of water-related terms differs between hydrology experts and the general audience
Venhuizen, G.J. ; Hut, Rolf ; Albers, Casper ; Stoof, C.R. ; Smeets, Ionica - \ 2019
Hydrology and Earth System Sciences 23 (2019)1. - ISSN 1027-5606 - p. 393 - 403.
Communication about hydrology-induced hazards is important, in order to keep the impact of floods, droughts et cetera as low as possible. However, sometimes the boundary between specialized and non-specialized language can be vague. Therefore, a close scrutiny of the use of hydrological vocabulary by both experts and laypeople is necessary. In this study, we compare the expert and lay definitions of 12 common water-related terms and 10 water-related pictures to see where misunderstandings might arise both in text and pictures. Our primary objective is to analyze the degree of agreement between experts and laypeople in their definition of the used terms. In this way, we hope to contribute to improving the communication between these groups in the future. Our study was based on a survey completed by 34 experts and 119 laypeople. Especially concerning the definition of water-related words there are some profound differences between experts and laypeople: words like river and river basin turn out to have a thoroughly different interpretation between the two groups. Concerning the pictures, there is much more agreement between the groups.
Taste matters most : Effects of package design on the dynamics of implicit and explicit product evaluations over repeated in-home consumption
Tijssen, Irene O.J.M. ; Zandstra, Elizabeth H. ; Boer, Annick den; Jager, Gerry - \ 2019
Food Quality and Preference 72 (2019). - ISSN 0950-3293 - p. 126 - 135.
Attractiveness - Healthiness - Implicit associations - Package design - Repeated exposure - Sensory evaluation

Package design influences consumers’ expectations of a product's sensory properties and expected healthiness and/or tastiness, and potentially also changes actual product perception during consumption. The robustness of these effects is far from clear, however. This study investigated the influence of package cues signalling either hedonic or healthy product properties on expectations and subsequent product evaluation over repeated consumption. In a between-subjects design, 92 participants evaluated product expectations and taste perceptions of a chocolate-sesame flavoured biscuit with a package emphasizing either its healthy (n = 44) or hedonic (n = 48) aspects, both at a central location (CLT) and during six home use tests (HUT), using both explicit (questionnaires) and implicit (IAT) measures. Package design significantly affected (p < 0.05) consumers’ expectations of the product. They expected the biscuit to be tastier, less attractive and less healthy in the hedonic package condition, and less tasty, more attractive and healthier in the healthy package condition. However, these effects did not transfer to actual product evaluations upon tasting, either blind or tasting in combination with viewing the package during the HUTs. Implicit attitudes did change as a result of repeated exposures, depending on the package consumers were provided with, indicating product-package interactions over time (p < 0.05). In conclusion, package design influences product expectations and associations with its healthiness and attractiveness, which is of relevance in product choice and purchase settings. However, at the stage of (repeated) consumption, intrinsic (sensory) properties become the dominant drivers of products’ sensory and hedonic evaluations, and the impact of package cues seems less potent.

Making sense of sensors in transition cow care
Hulsen, Jan ; Vreeburg, N. ; Eerdenburg, F.J.C.M. van; Hooijer, G. ; Hut, P. ; Harbers, Arnold ; Stassen, E.N. - \ 2018
Hoard's Dairyman (2018). - ISSN 0018-2885 - p. 265 - 265.
Ode aan een andere manier van jagen
Boonman-Berson, Susan - \ 2018
De Balie kijkt Het Hut Syndicaat met Maarten Doorman
Boonman-Berson, Susan - \ 2018
HESS Opinions: Science in today's media landscape - Challenges and lessons from hydrologists and journalists
Lutz, Stefanie R. ; Popp, Andrea ; Emmerik, Tim Van; Gleeson, Tom ; Kalaugher, Liz ; Möbius, Karsten ; Mudde, Tonie ; Walton, Brett ; Hut, Rolf ; Savenije, Hubert ; Slater, Louise J. ; Solcerova, Anna ; Stoof, Cathelijne R. ; Zink, Matthias - \ 2018
Hydrology and Earth System Sciences 22 (2018)7. - ISSN 1027-5606 - p. 3589 - 3599.

Media such as television, newspapers and social media play a key role in the communication between scientists and the general public. Communicating your science via the media can be positive and rewarding by providing the inherent joy of sharing your knowledge with a broader audience, promoting science as a fundamental part of culture and society, impacting decision- and policy-makers, and giving you a greater recognition by institutions, colleagues and funders. However, the interaction between scientists and journalists is not always straightforward. For instance, scientists may not always be able to translate their work into a compelling story, and journalists may sometimes misinterpret scientific output. In this paper, we present insights from hydrologists and journalists discussing the advantages and benefits as well as the potential pitfalls and aftermath of science-media interaction. As we perceive interacting with the media as a rewarding and essential part of our work, we aim to encourage scientists to participate in the diverse and evolving media landscape. With this paper, we call on the scientific community to support scientists who actively contribute to a fruitful science-media relationship..

Measurements and Observations in the XXI century (MOXXI) : innovation and multi-disciplinarity to sense the hydrological cycle
Tauro, Flavia ; Selker, John ; Giesen, Nick van de; Abrate, Tommaso ; Uijlenhoet, Remko ; Porfiri, Maurizio ; Manfreda, Salvatore ; Caylor, Kelly ; Moramarco, Tommaso ; Benveniste, Jerome ; Ciraolo, Giuseppe ; Estes, Lyndon ; Domeneghetti, Alessio ; Perks, Matthew T. ; Corbari, Chiara ; Rabiei, Ehsan ; Ravazzani, Giovanni ; Bogena, Heye ; Harfouche, Antoine ; Brocca, Luca ; Maltese, Antonino ; Wickert, Andy ; Tarpanelli, Angelica ; Good, Stephen ; Lopez Alcala, Jose Manuel ; Petroselli, Andrea ; Cudennec, Christophe ; Blume, Theresa ; Hut, Rolf ; Grimaldi, Salvatore - \ 2018
Hydrological Sciences Journal 63 (2018)2. - ISSN 0262-6667 - p. 169 - 196.
experimental hydrology - hydrological measurements - IAHS - innovation - measurements and Observations in the XXI century (MOXXI) - sensors
To promote the advancement of novel observation techniques that may lead to new sources of information to help better understand the hydrological cycle, the International Association of Hydrological Sciences (IAHS) established the Measurements and Observations in the XXI century (MOXXI) Working Group in July 2013. The group comprises a growing community of tech-enthusiastic hydrologists that design and develop their own sensing systems, adopt a multi-disciplinary perspective in tackling complex observations, often use low-cost equipment intended for other applications to build innovative sensors, or perform opportunistic measurements. This paper states the objectives of the group and reviews major advances carried out by MOXXI members toward the advancement of hydrological sciences. Challenges and opportunities are outlined to provide strategic guidance for advancement of measurement, and thus discovery.
Using sensors to monitor behaviour at the dairy farm
Eerdenburg, F.J.C.M. van; Hut, P. ; Hooijer, G. ; Harbers, Arnold ; Stassen, E.N. ; Hulsen, Jan - \ 2017
In: Proceedings of the ISAE Benelux conference 2017 International Society for Applied Ethology (ISAE) - p. 20 - 20.
Using sensors to monitor behaviour at the dairy farm
Eerdenburg, Frank J.C.M. ; Hut, P. ; Hooijer, G. ; Harbers, A. ; Stassen, E.N. ; Hulsen, J. - \ 2017
In: Proceedings of the 7th International Conference on the Assessment of Animal Welfare at Farm and Group Level. - Wageningen : Wageningen Academic Publishers - ISBN 9789086863143 - p. 228 - 228.
Sensors can measure various types of behaviour automatically in a dairy herd. They can,therefore, be used to monitor a herd and the computer can detect deviations of normalbehaviour and give an attention to the farmer. In order to do so, normal baseline values areneeded. Since these may vary due to parity and housing conditions, the aim of this study wasto investigate the effects of parity and freestall bedding (cow matrass vs deep litter) on dailylying time, locomotion, standing and eating time from 42d a.p. – 28d p.p. Sixteen Dutch dairyfarms (3,158 cows) were used in this study and the number of steps per day, time of standingand lying (in sec/2 h period)and time eating (in sec/2 h) were collected by means of Nedapsmart tags (Groenlo, the Netherlands). Furthermore, in the first two weeks post-partum bloodsamples were collected to measure BHB levels. T-tests and timeseries were used for comparison.The results of locomotion revealed that primiparous cows made 833 (SD 132; P<0.001) moresteps on daily basis in comparison with multiparous cows. Animals housed on cow matrassesmade on daily basis on average 621 (SD 30; P<0.001) more steps vs animals in stalls with deeplitter bedding. Primiparous cows spent daily on average 64 minutes (SD 4.8; P<0.001) less timelying down and animals on farms with cow matrasses lie on daily basis around 30 (SD 17.3;P<0.001) minutes less when compared with animals housed on farms with deep litter bedding.The number of lying bouts increased from 6 to 9 per day 1 day before calving and decreased to7 per day after calving. The time lying per day decreased before calving. And the average lyingtime increases again in the first week post-partum. Cows that had a subclinical ketosis postpartumwere eating half an hour less during the dry period. Already 42 days before calving thisdifference could be observed. It became clear that with sensors differences in behaviour duringthe dry period can be detected that could lead to managerial interventions to reduce the riskfor diseases post-partum. This study is ongoing and more data will be obtained.
Erfgoedconstructies in landschapspraktijken van burgers
Braaksma, Patricia - \ 2017
Wageningen University. Promotor(en): Joks Janssen, co-promotor(en): A.N. van der Zande; Maarten Jacobs. - Wageningen : Wageningen University - ISBN 9789462571549 - 231
landschap - erfgoed - cultureel erfgoed - cultuurgeschiedenis - nederland - landscape - heritage areas - cultural heritage - cultural history - netherlands

Decisions to cut down monumental trees or demolish historic buildings can always count on civilian protests. Every year, the Dutch tradition of Zwarte Piet (‘Black Pete’) is heavily debated, the protests almost a tradition themselves. There are regular reports about concerned people protesting the disappearance of heritage or the damage about to be done to it. People value traditions, narratives or historic objects, and these are called heritage. Not everyone values these in the same way, though. Where to one person Zwarte Piet is inextricably bound up with the Sinterklaas festivities, to another he is nothing less than an expression of racism. What constitutes heritage depends on the meaning people assign to objects, events, stories and traditions. In the past, experts usually decided what was considered to be heritage. The examples show that civilians also assign heritage meaning and thus construct heritage as well. Policy-makers have expressed a wish to cooperate with citizens to come to a concerted and widely supported valuation of heritage. Since heritage is not an objective and static given, but a product of dynamic assignment of meaning, groups of people can produce multiform heritage values. Insights into what meanings people assign to heritage in their everyday environments could on the one hand help preserve the existing values regarding heritage, sites and landscapes and respect these. On the other hand they can be helpful in the development of policies for heritage and the efforts of the government for more cooperation with citizens. The aim of this study is to obtain these insights.

Theoretical perspective and research questions

In science, the concept of heritage is the subject of lively discussions. Traditionally, heritage was presented as a collection of artefacts, of which the historic characteristics and the ways in which they could be shown were studied. Later, the attention shifted to heritage as a construction of meaning. The study focused primarily on representations; the way old things were linguistically represented by different groups of people. The material artefacts thus disappeared from view. More recently, heritage researchers propose an integrated approach: no longer an exclusive focus on either the artefacts or the representations thereof, but rather the relations between these should be the object of study. This study is consistent with the latter conceptualisation, and departs from the matching theoretical perspective of landscape practices. These are routines shared by groups of interacting people who are involved with landscapes. In these landscape practices, motives, actions, material objects and the meanings assigned to them form a coherent whole. This theoretical approach is ideally suited to study heritage as meaning construction on a micro-level (the level of people's daily lives), and to understand this assignment of meaning against the background of routines in which actions and material objects are also important. In addition to the characterisation of different landscape practices in which heritage is constructed, this research is meant to make four additional contributions to heritage literature. First, heritage studies so far focused on explicit meanings, i.e. meanings in which historical artefacts are explicitly presented as heritage. From practice theory, however, it follows that there can also be implied meanings and that these can be just as relevant. These are meanings assigned to historical artefacts, without presenting these as heritage. Secondly, I focused on the ways experts and people in practices exchange knowledge. In literature, this exchange has mostly been studied as a conflict, but other forms, such as cooperation, are equally conceivable. Thirdly, I looked for changes in heritage constructions resulting from recent or upcoming spatial changes in the surroundings. Studies on the assignment of meaning to places show that these meanings may shift when change is about to come to a place; whether and how this is the case for heritage meanings is still a largely open question. Fourthly, I looked at the willingness of people to cooperate in heritage management. It is because of this perspective of practice theory that this study can add to the studies on representations of heritage, in which the emphasis is often on conflicts between governments and citizens.

On the basis of these considerations, the following research questions were leading for the empirical research:

Which motives, activities, and scenic elements play a role in landscape practices, and what meanings do people in these practices assign to historic artefacts?

To what extent is the distinction between implicit and explicit meanings relevant for understanding the construction of heritage in landscape practices?

What are the roles of external expert knowledge in the construction of scenic heritage in landscape practices?

To what extent do spatial changes influence the heritage constructions in landscape practices?

To what extent are citizens in landscape practices willing to participate with the government in taking care of heritage?

Research design

To answer the research questions, a qualitative research design was chosen. I have collected information about motives, activities and meanings by conducting [aantal] semi-structured interviews with people who are active in landscape practices. These interviews were conducted in four study areas: the Tjongervallei, the Roerstreek, the Amstelland and the IJsselvallei. In two of these areas spatial changes play a prominent role (Amstelland and IJsselvallei), and in the other two they do not. Moreover, historical experts highly value two of these areas (Roerstreek and Amstelland) and not the other two. This combination of study areas was chosen with the research questions about the influence of spatial changes and the roles of expert knowledge in mind. In the phase of qualitative data analysis, the information from the interviews was processed by systematically coding quotes from the interviews, based on similarities and differences in these quotes, and on the concepts that gave direction to the research.


Seven distinctive types of landscape practices were found in the different study areas. In practices centring around the collection of historical information, the activities for the most part consist of visiting archives and libraries, and organising the obtained information. The focus is on the social aspects of history, what the life of our ancestors was like. Within these practices, historic landscape features are assigned meaning as signs of this social history. An old turf hut, for instance, reflects the hard life of peat workers in the past.

Within practices focused on the education of local history, people organise exhibitions and tours and develop teaching materials for schools. These people like to make a contribution to society, to be active and to provide younger generations with knowledge about history. Landscape elements that show an area's history are valuable to these people.

The people in conservation practices focus on legislation, for which they administer and collect data on species and their habitat. They also go out to work on small projects to contribute to nature. That is what they love to do most. Historical elements and features that also have a high ecological value have a special meaning within these practices.

Being active in the landscape characterises the practices of landscape maintenance, activities such as pruning, pollarding and digging. What motivates these people are the social contacts they have during these activities and that these are outdoor activities. The objects of their activities are central to the assignment of meaning to the surroundings. The aesthetic meaning is paramount here, while the historical dimension hardly plays a role.

In practices focused on monument conservation, getting other local residents involved is an important activity. Being active for the community and preserving something for future generations are important motivations for participants. It is not the larger landscape structures, but specific historical objects that are of interest. If there are spatial changes, these historical meanings are strongly articulated and defended, even in court, if necessary.

In the practice of landscape development, found only in the Tjongervallei, people make plans for the area and organise consultations. It is about improving the landscape and using history to this end. Therefore, there is special emphasis on historical artefacts, which become meaningful in new plans such as the development of tourist routes.

Depending on the study area, protest activities or support activities are at the heart of landscape development practices. When protesting proposed plans, this means taking part in participation procedures and court procedures. Support activities involve persuading other locals of their perspectives on the future, in order to prevent administrators of making decisions that are not in line with those perspectives. Historical landscape structures, rather than specific objects, are assigned meaning from the desire to steer spatial developments.

Throughout the practices and study areas, different dominant modes of production of meaning were found, within which heritage is constructed: on the basis of landscape aesthetics, in response to upcoming or recent spatial changes, from the perspective of people's own family history, the wish to make a social contribution, and on the basis of utility value.

This research shows that assigning meanings to historic landscape features and structures is diverse. This diversity does not only exist between study areas but also between practices within an area. Heritage is therefore a social construct. At the same time, heritage is not a completely random construct. Some historical artefacts easily get assigned meaning, and therefore play an important role in different practices. Also, these heritage meanings are often understandable seeing the activities, motives and knowledge in the relevant practices.

The theoretically assumed distinction between explicit and implicit meanings does indeed turn out to be relevant. Some people assign meaning to historical objects in a landscape, while there is not any actual historical connotation. In their view, for instance, the objects are valuable in relation to the aesthetics of the landscape, or as elements with value for nature.

Different ways of knowledge exchange with experts were found in this research. Sometimes participants in practices worked together with experts to gain knowledge. Especially in practices that revolve around collecting historical information amateur archaeologists and professional archaeologists work together to increase historical knowledge. In conservation practices, people consult experts to become familiar with statutory frameworks that are relevant to their activities.

Practice members and experts appreciate each other's work. Within some practices, such as that of monument conservation, expert knowledge and consultation are actively sought out to strengthen the legitimacy of arguments. People think, for example, that the likelihood of success in court cases increases when an expert agrees with them.

The extent to which upcoming and recent spatial changes are of influence varies greatly between landscape practices. In some practices, activities and the assignment of meaning explicitly address these spatial changes. People protest against changes using various means, such as public inquiries and lawsuits, and by accentuating or even newly constructing historical meanings of objects as a strategy to influence changes. Other practices do not react to spatial changes, because the historical artefacts that are important within these practices remain untouched by these changes.

This research shows that many people are prepared to take care of heritage in their own way. We also see cooperation with the government. Sometimes practices execute public tasks through volunteer work, and vice versa the government facilitates some practices through grants and by organising public inquiries. However, this does not mean that we can already see joint assignment of heritage meanings and values. In its wake, a broad willingness to participate in public policies for heritage was not found. The way in which the government frames interaction can be a major obstacle. In the IJsselvallei, there is discontent among citizens about the small extent to which they can share their perspectives within the planning procedures as established by the government.

Conclusion and discussion

Heritage literature often emphasises the importance of heritage for people. This research shows that it is indeed important, but also that we should not exaggerate this importance. The interest in history is usually fragmented and often limited to a specific object that is of interest in a landscape practice. Moreover, this study looked at people who are actively involved in the landscape, and landscape heritage is probably even less important to people that are not actively involved. Heritage researchers also often emphasise that heritage is important for people's identity formation. Although this issue has not been examined directly empirically, the findings do necessitate a nuancing of this idea. The interviewees hardly indicate that historical artefacts are important to their sense of identity. Some measure of identity contribution does seem plausible though, because, for example, people find some objects typical for the region to which they feel connected. The main attraction of landscape practices for the participants lies in the social relations. That is what it is really about for most people, and that is what makes them feel good. In this sense, historical artefacts are often, but not always, a reason for doing things together, and that is what the participants enjoy the most.

Social Relevance

The current heritage policy focuses increasingly on citizens. Policymakers think that shared values ​​should be established in the collaboration between heritage professionals and citizens. This study provides insights into both the conflicts that arise in practice and the current cooperation between citizens and heritage professionals.

A striking finding in the studied landscape practices is that there are no conflicts between practices themselves. Many meanings assigned to heritage, although different, are not inherently conflicting in the sense that they are mutually exclusive. The importance of social relations for those involved in a landscape practice means that they do not easily start a conflict. While conflicts between practices were not found in this study, there are many conflicts between landscape practices and governments. Spatial change is a major driver of conflict. Especially in those situations, governments should therefore focus on interactive participation processes in a planning context.

In addition to the negatively oriented cooperation between citizens and governments, this research also identified a positively oriented cooperation. These forms of cooperation are not very interactive yet. It is therefore questionable whether they will lead to shared heritage values. For governments and other heritage professionals, landscape practices are interesting contacts. They are organized and often already actively involved in heritage, so they are easier to approach than individual citizens. To give new meaning to heritage policy with the shared values ​​of governments and citizens at the centre, a change is required in the way professionals work. More than they do now, participatory processes should focus on the actions of people and the diversity of the meanings they assign to heritage. If they do, the results from this study indicate that it might well be possible to share the care for heritage.

Geoscience on television : A review of science communication literature in the context of geosciences
Hut, Rolf ; Land-Zandstra, Anne M. ; Smeets, Ionica ; Stoof, Cathelijne R. - \ 2016
Hydrology and Earth System Sciences 20 (2016)6. - ISSN 1027-5606 - p. 2507 - 2518.

Geoscience communication is becoming increasingly important as climate change increases the occurrence of natural hazards around the world. Few geoscientists are trained in effective science communication, and awareness of the formal science communication literature is also low. This can be challenging when interacting with journalists on a powerful medium like TV. To provide geoscience communicators with background knowledge on effective science communication on television, we reviewed relevant theory in the context of geosciences and discuss six major themes: scientist motivation, target audience, narratives and storytelling, jargon and information transfer, relationship between scientists and journalists, and stereotypes of scientists on TV. We illustrate each theme with a case study of geosciences on TV and discuss relevant science communication literature. We then highlight how this literature applies to the geosciences and identify knowledge gaps related to science communication in the geosciences. As TV offers a unique opportunity to reach many viewers, we hope this review can not only positively contribute to effective geoscience communication but also to the wider geoscience debate in society.

Development and optimization of the Suna trap as a tool for mosquito monitoring and control
Hiscox, A.F. ; Otieno, B. ; Kibet, A. ; Mweresa, C.K. ; Omusula, P. ; Geier, M. ; Rose, A. ; Mukabana, W.R. ; Takken, W. - \ 2014
Malaria Journal 13 (2014). - ISSN 1475-2875 - 14 p.
human-landing catches - cdc light-trap - anopheles-gambiae - carbon-dioxide - malaria transmission - field-evaluation - diptera-culicidae - equatorial-guinea - vector control - western kenya
Background Monitoring of malaria vector populations provides information about disease transmission risk, as well as measures of the effectiveness of vector control. The Suna trap is introduced and evaluated with regard to its potential as a new, standardized, odour-baited tool for mosquito monitoring and control. Methods Dual-choice experiments with female Anopheles gambiae sensu lato in a laboratory room and semi-field enclosure, were used to compare catch rates of odour-baited Suna traps and MM-X traps. The relative performance of the Suna trap, CDC light trap and MM-X trap as monitoring tools was assessed inside a human-occupied experimental hut in a semi-field enclosure. Use of the Suna trap as a tool to prevent mosquito house entry was also evaluated in the semi-field enclosure. The optimal hanging height of Suna traps was determined by placing traps at heights ranging from 15 to 105 cm above ground outside houses in western Kenya. Results In the laboratory the mean proportion of An. gambiae s.l. caught in the Suna trap was 3.2 times greater than the MM-X trap (P <0.001), but the traps performed equally in semi-field conditions (P = 0.615). As a monitoring tool , the Suna trap outperformed an unlit CDC light trap (P <0.001), but trap performance was equal when the CDC light trap was illuminated (P = 0.127). Suspending a Suna trap outside an experimental hut reduced entry rates by 32.8% (P <0.001). Under field conditions, suspending the trap at 30 cm above ground resulted in the greatest catch sizes (mean 25.8 An. gambiae s.l. per trap night). Conclusions The performance of the Suna trap equals that of the CDC light trap and MM-X trap when used to sample An. gambiae inside a human-occupied house under semi-field conditions. The trap is effective in sampling mosquitoes outside houses in the field, and the use of a synthetic blend of attractants negates the requirement of a human bait. Hanging a Suna trap outside a house can reduce An. gambiae house entry and its use as a novel tool for reducing malaria transmission risk will be evaluated in peri-domestic settings in sub-Saharan Africa.
Absence of Close-Range Excitorepellent Effects in Malaria Mosquitoes Exposed to Deltamethrin-Treated Bed Nets
Spitzen, J. ; Ponzio, C.A.M. ; Koenraadt, C.J.M. ; Pates Jamet, H.V. ; Takken, W. - \ 2014
American Journal of Tropical Medicine and Hygiene 90 (2014)6. - ISSN 0002-9637 - p. 1124 - 1132.
resistant anopheles-gambiae - culex-quinquefasciatus mosquitos - experimental hut trials - piperonyl butoxide - diptera-culicidae - permanet(r) 3.0 - helicoverpa-armigera - impregnated bednets - exiting behavior - child-mortality
Flight behavior of insecticide-resistant and susceptible malaria mosquitoes approaching deltamethrin-treated nets was examined using a wind tunnel. Behavior was linked to health status (dead or alive) using comparisons between outcomes from free-flight assays and standard World Health Organization (WHO) bioassays. There was no difference in response time, latency time to reach the net, or spatial distribution in the wind tunnel between treatments. Unaffected resistant mosquitoes spent less time close to (<30 cm) treated nets. Nettings that caused high knockdown or mortality in standard WHO assays evoked significantly less mortality in the wind tunnel; there was no excitorepellent effect in mosquitoes making contact with the nettings in free flight. This study shows a new approach to understanding mosquito behavior near insecticidal nets. The methodology links free-flight behavior to mosquito health status on exposure to nets. The results suggest that behavioral assays can provide important insights for evaluation of insecticidal effects on disease vectors
De ongehoorzame overheid, een verkenning van de discoursen van de gemeentelijke overheden over burgerinitiatieven [in ontwikkeling]
Coninx, I. ; Kruit, J. ; During, R. - \ 2012
Wageningen : Alterra (Zo doen wij dat hier! [4]) - 35
sociale participatie - publieke participatie - burgers - overheid - communicatie - rechtspositie - governance - social participation - public participation - citizens - public authorities - communication - legal status
Kinderen uit de wijk Welten in Heerlen bouwden een boomhut op een diffuus stuk bos langs de autobaan. Een onbeduidend gebiedje tussen openbaar groen en het verkeerstalud. De politie maande hen echter aan de hut af te breken, wegens het ontbreken van een bouwvergunning. Ook kregen ze te horen dat het 400 euro zou kosten als ze door zouden bouwen. Ouders stapten naar de gemeente. Ambtenaren beaamden dat huttenbouwen mogelijk moest worden binnen hun gemeente en onderzochten hoe een spontane actie binnen de gemeente kon worden gefaciliteerd. Toen begon het probleem pas echt. Er moest beleid worden gemaakt voor een tijdelijke invulling van de openbare ruimte. Welke bosjes zijn wel geschikt en welke niet? Hoe moest een hut geconstrueerd worden om aan veiligheidseisen te voldoen? Wat is een hut: permanente bewoning of semi permanente bewoning. Als je daarin wilt verblijven, hoe lang mag dat dan? Hoe hoog mogen de hutten zijn en hoe hoog in de boom mogen de hutten worden gebouwd? Een werkgroep werd in het leven geroepen. Deze groep werd belast met het ontwerpen van regels voor een dergelijke openbare ruimteclaim. Dat duurde even.... Burgerinitiatieven verhouden zich altijd tot een bestuurlijke context. Het succes van een burgerinitiatief wordt in enige mate dan ook beïnvloed door die bestuurlijke context. Concreet gaat het om de beschikbaar gestelde (bestuurlijke/juridische/planologische) ruimte voor burgers om het initiatief op poten te zetten. Soms biedt een overheid weerstand, maakt ze het de burgers moeilijk en soms zelfs onmogelijk om tot actie over te gaan. Soms ondersteunt een overheid burgerinitiatieven met geld, toelating en steun. Mogelijk is een overheid zodanig enthousiast over een burgerinitiatief dat ze het wenst over te nemen. Voor burgers in een burgerinitiatief kan het erg frustrerend zijn dat een overheid niet die rol op zich neemt die deze burgers verwachten. Om hier als burgerinitiatief beter mee om te kunnen gaan, is het handig om meer inzicht te krijgen in de discoursen die overheden hanteren ten aanzien van burgerinitiatieven.
Aaltjes verdrinken : Onderzoek PPO te Lelystad
Hut, Hans ; PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2012
Boerderij 98 (2012)4. - ISSN 0006-5617 - p. 4 - 5.
Evaluation of farmed cod products by a trained sensory panel and consumers in different test settings
Sveinsdottir, K. ; Martinsdottir, E. ; Thorsdottir, F. ; Schelvis-Smit, A.A.M. ; Kole, A. ; Thorsdottir, I. - \ 2010
Journal of Sensory Studies 25 (2010)2. - ISSN 0887-8250 - p. 280 - 293.
central location test - home-use test - food acceptability - liking ratings - acceptance - environment - attitudes - choice - fish
Sensory characteristics of farmed cod exposed to low or conventional stress levels prior to slaughter were evaluated by a trained sensory panel. Consumers in two different settings, central location test (CLT) and home-use test (HUT), also tasted the products and rated them according to overall liking on a 9-point hedonic scale and sensory attributes on a 9-point intensity scale. Differences were observed in texture attributes of the two cod groups by the trained sensory panel. Consumers in the CLT distinguished between the two cod groups whereas consumers in the HUT setting did not. Consumers in the CLT scored the products lower with regard to liking, and evaluated sensory attributes differently from consumers in the HUT setting. The results indicated that the cooking method chosen by consumers in the HUT setting influenced the consumer evaluation of cod. Similar cooking methods used in CLT and HUT produced similar results of liking. PRACTICAL APPLICATIONS This paper presents a comparison of sensory evaluation carried out by a trained sensory panel and consumer evaluation of farmed fish. Cod produced with conventional and reduced stress prior to slaughter differed in texture attributes according to sensory evaluation. Information about consumer liking of the end-product when changing production systems of farmed fish is very important. The sensory evaluation by a trained panel provides good product knowledge, but to be able to estimate the actual consumer liking of the fish products, consumer studies are needed. The results indicated that a central location test (CLT) could be used to predict consumer acceptance in a real-life setting, given that similar cooking methods are used in both settings. Fish is a very perishable product, and its sensory quality depends very much on factors such as storage time and preparation. Therefore, CLT may be well suited for consumer testing of fish products.
The entomopathogenic fungus Beauveria bassiana reduces instantaneous blood feeding in wild multi-insecticide-resistant Culex quinquefasciatus mosquitoes in Benin, West Africa
Howard, A.F.V. ; N'Guessan, R. ; Koenraadt, C.J.M. ; Asidi, A. ; Farenhorst, M. ; Akogbéto, M. ; Thomas, M.B. ; Knols, B.G.J. ; Takken, W. - \ 2010
Parasites & Vectors 3 (2010). - ISSN 1756-3305 - 11 p.
anopheles-gambiae-s.s. - metarhizium-anisopliae - pyrethroid resistance - malaria mosquitos - treated nets - infection - culicidae - diptera - vectors - thermotolerance
Background Mosquito-borne diseases are still a major health risk in many developing countries, and the emergence of multi-insecticide-resistant mosquitoes is threatening the future of vector control. Therefore, new tools that can manage resistant mosquitoes are required. Laboratory studies show that entomopathogenic fungi can kill insecticide-resistant malaria vectors but this needs to be verified in the field. Methods The present study investigated whether these fungi will be effective at infecting, killing and/or modifying the behaviour of wild multi-insecticide-resistant West African mosquitoes. The entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were separately applied to white polyester window netting and used in combination with either a permethrin-treated or untreated bednet in an experimental hut trial. Untreated nets were used because we wanted to test the effect of fungus alone and in combination with an insecticide to examine any potential additive or synergistic effects. Results In total, 1125 female mosquitoes were collected during the hut trial, mainly Culex quinquefasciatus Say. Unfortunately, not enough wild Anopheles gambiae Giles were collected to allow the effect the fungi may have on this malaria vector to be analysed. None of the treatment combinations caused significantly increased mortality of Cx. quinquefasciatus when compared to the control hut. The only significant behaviour modification found was a reduction in blood feeding by Cx. quinquefasciatus, caused by the permethrin and B. bassiana treatments, although no additive effect was seen in the B. bassiana and permethrin combination treatment. Beauveria bassiana did not repel blood foraging mosquitoes either in the laboratory or field. Conclusions This is the first time that an entomopathogenic fungus has been shown to reduce blood feeding of wild mosquitoes. This behaviour modification indicates that B. bassiana could potentially be a new mosquito control tool effective at reducing disease transmission, although further field work in areas with filariasis transmission should be carried out to verify this. In addition, work targeting malaria vector mosquitoes should be carried out to see if these mosquitoes manifest the same behaviour modification after infection with B. bassiana conidia
Impact of promoting longer-lasting insecticide treatment of bed nets upon malaria transmission in a rural Tanzanian setting with pre-existing high coverage of untreated nets
Russell, T.L. ; Lwetoijera, D.W. ; Maliti, D. ; Chipwaza, B. ; Kihonda, J. ; Charlwood, J.D. ; Smith, T.A. ; Lengeler, C. ; Mwanyangala, M.A. ; Nathan, R. ; Knols, B.G.J. ; Takken, W. ; Killeen, G.F. - \ 2010
Malaria Journal 9 (2010). - ISSN 1475-2875 - 14 p.
anopheles-gambiae complex - papua-new-guinea - plasmodium-falciparum infection - entomologic inoculation rates - experimental hut trials - blood-feeding behavior - treated nets - mosquito nets - impregnated bednets - arabiensis diptera
Background The communities of Namawala and Idete villages in southern Tanzania experienced extremely high malaria transmission in the 1990s. By 2001-03, following high usage rates (75% of all age groups) of untreated bed nets, a 4.2-fold reduction in malaria transmission intensity was achieved. Since 2006, a national-scale programme has promoted the use of longer-lasting insecticide treatment kits (consisting of an insecticide plus binder) co-packaged with all bed nets manufactured in the country. Methods The entomological inoculation rate (EIR) was estimated through monthly surveys in 72 houses randomly selected in each of the two villages. Mosquitoes were caught using CDC light traps placed beside occupied bed nets between January and December 2008 (n = 1,648 trap nights). Sub-samples of mosquitoes were taken from each trap to determine parity status, sporozoite infection and Anopheles gambiae complex sibling species identity. Results Compared with a historical mean EIR of ~1400 infectious bites/person/year (ib/p/y) in 1990-94; the 2008 estimate of 81 ib/p/y represents an 18-fold reduction for an unprotected person without a net. The combined impact of longer-lasting insecticide treatments as well as high bed net coverage was associated with a 4.6-fold reduction in EIR, on top of the impact from the use of untreated nets alone. The scale-up of bed nets and subsequent insecticidal treatment has reduced the density of the anthropophagic, endophagic primary vector species, Anopheles gambiae sensu stricto, by 79%. In contrast, the reduction in density of the zoophagic, exophagic sibling species Anopheles arabiensis was only 38%. Conclusion Insecticide treatment of nets reduced the intensity of malaria transmission in addition to that achieved by the untreated nets alone. Impacts were most pronounced against the highly anthropophagic, endophagic primary vector, leading to a shift in the sibling species composition of the A. gambiae complex
Optimization of formulation and delivery technology of entomopathogenic fungi for malaria vector control
Mnyone, L.L. - \ 2010
Wageningen University. Promotor(en): Willem Takken; Marcel Dicke. - [S.l.] : S.n. - ISBN 9789085857877 - 125
culicidae - vectoren, ziekten - malaria - vectorbestrijding - entomopathogene schimmels - biologische bestrijding - toepassing - formuleringen - culicidae - disease vectors - malaria - vector control - entomogenous fungi - biological control - application - formulations
Vector control is one of the most effective means of controlling mosquito-borne diseases such as malaria. The broad goal of this strategy is to protect individuals against infective mosquito bites and, at the community level, to reduce the intensity of disease transmission. With the deployment of mainly insecticide-treated nets (ITN) and indoor residual spraying (IRS), aided by effective drug treatment, certain countries particularly those within the low endemic zones have documented more than 50% reduction in malaria cases over the past decade. To keep up the pace and expand effective malaria control, in line with the global effort to eliminate malaria, IRS and ITN need to be complemented with alternative control methods. Indeed, neither long lasting insecticide nets (LLINs) nor IRS alone will be sufficient to achieve and maintain interruption of transmission in malaria holoendemic and hyperendemic areas. Besides, the sustainability of both methods is inescapably threatened by mosquito resistance to insecticides. Scientific evidence indicates that biological control based on entomopathogenic fungi has the potential to complement existing vector control methods. Two species of entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana, have demonstrated ability to infect and kill adult malaria vectors.

This thesis describes the results of a series of laboratory investigations followed by small scale field trials in Tanzania in an area of high malaria endemicity, with abundant populations of the malaria vector Anopheles gambiae sensu lato. The overall aim was to optimize fungal formulations, develop delivery techniques that maximize fungus infection rates in wild malaria populations, evaluate impact on survival of these mosquitoes and asses the impact on malaria transmission levels. A series of variables that we hypothesized affect the efficacy and persistence of the fungal isolates Metarhizium anisopliae ICIPE-30, M. anisopliae IP 46 and Beauveria bassiana I93-825 against adult An. gambiae were assessed. These included a) conidia concentration (1×107- 4×1010 conidia m-2), b) exposure time (15 min - 6 h), c) delivery substrates (netting, cotton cloth & mud wall), d) mosquito age (2 - 12 d), e) time since blood meal (3 - 72 h) as well as f) mosquito behaviour (repellency by conidial formulations). Co-formulations of M. anisopliae ICIPE-30 and B. bassiana I93-825 in ratios of 4:1, 2:1 & 1:1 were also tested. Metarhizium anisopliae IP 46 was exposed to An. gambiae and An. arabiensis to determine its pathogenicity on these mosquito species before being used for the field trials. Mosquitoes were exposed to fungal formulations applied on paper inside holding tubes, except when different delivery substrates were assessed. For the delivery substrates, sections of netting and black cotton cloth were joined using Velcro strips to fit over 20 × 20 × 20 cm wire frame cages; and mud-lined plywood panels were similarly assembled into 20 × 20 × 20 cm cages. Laboratory experiments were performed using laboratory reared mosquitoes at the Ifakara Health Institute, Ifakara, Tanzania. Following the laboratory experiments, fungal formulations were assayed in experimental hut trials in a field setting at Lupiro village (Ulanga District, Tanzania), a rural hamlet 30 km south of Ifakara. Five different techniques that each exploited the behaviour of mosquitoes when entering (eave netting, eave curtains, eave baffles), host-seeking (cloth strips hung next to bed nets) or resting (cloth panels) were assessed.

The degree at which mosquito survival was reduced varied with conidia concentration; 2×1010 conidia m-2 was the optimum concentration above which no further reductions in survival were detectable. Co-formulations exerted neither synergistic nor additive effect in reducing mosquito survival. The exposure of mosquitoes to fungal formulations for time periods as short as 15 and 30 min was adequate to achieve 100% mortality of mosquitoes within 14 d post exposure. Longer exposure times did not result in a more rapid killing effect. Conidia impregnated on papers remained infective up to 28 d post application, and such trait did not seem to be influenced by the conidia concentration. Mosquitoes of the age between 2-12 d equally succumbed to fungus infection, with them, however, being relative more susceptible when non-blood fed. Oil-formulations of the fungi did not exhibit any repellency to mosquitoes. Metarhizium anisopliae IP 46 was pathogenic to both An. gambiae and An. arabiensis. Conidia were more effective when applied on mud panels and cotton cloth compared with polyester netting. Cotton cloth and mud, therefore, represent potential surfaces for delivering fungi to mosquitoes in the field.
Two delivery techniques, cotton cloth eave baffles and strips hung next to the bed net were successful in exploiting the behaviour of wild anopheline mosquitoes. Up to 75% of house-entering mosquitoes became infected with fungus applied with either technique. By contrast, eave netting, eave curtains and cotton panels placed next to the bed net were ineffective in infecting mosquitoes with sufficiently high doses of fungi to affect their survival. Based on the survival data of the mosquitoes infected with fungus by means of eave baffles, model estimates indicated that fungus alone can reduce EIR by more than 75%.

In conclusion, these findings indicate that with well-optimized fungal formulations and correctly-designed delivery techniques, a high proportion of house-entering wild malaria mosquitoes can be infected with entomopathogenic fungi to achieve considerable reduction in their survival and possibly malaria transmission. More importantly, these findings provide baseline information that is highly relevant for designing and conducting large-scale field trials to validate the projected impact of fungal infection under realistic field situations.

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