W. Vanhove - Academia.edu (original) (raw)

Papers by W. Vanhove

In this paper, we introduce the notion of port-Lagrangian systems in nonequilibrium thermodynamic... more In this paper, we introduce the notion of port-Lagrangian systems in nonequilibrium thermodynamics, which is constructed by generalizing the notion of port-Lagrangian systems for nonholonomic mechanics proposed in Yoshimura and Marsden [2006c], where the notion of interconnections is described in terms of Dirac structures. The notion of port-Lagrangian systems in nonequilibrium thermodynamics is deduced from the variational formulation of nonequilibrium thermodynamics developed in Gay-Balmaz and Yoshimura [2017a,b]. It is a type of Lagrange-d'Alembert principle associated to a specific class of nonlinear nonholonomic constraints, called phenomenological constraints, which are associated to the entropy production equation of the system. To these phenomenological constraints are systematically associated variational constraints, which need to be imposed on the variations considered in the principle. In this paper, by specifically focusing on the cases of simple thermodynamic systems with constraints, we show how the interconnections in thermodynamics can be also described by Dirac structures on the Pontryagin bundle as well as on the cotangent bundle of the thermodynamic configuration space. Each of these Dirac structures is induced from the variational constraint. Furthermore, the variational structure associated to this Dirac formulation is presented in the context of the Lagrange-d'Alembert-Pontryagin principle. We illustrate our theory with some examples such as a cylinder-piston with ideal gas as well as an LCR circuit with entropy production due to a resistor.

Forensic science international, Jan 31, 2017

Together, the Netherlands and Belgium are the largest indoor cannabis producing countries in Euro... more Together, the Netherlands and Belgium are the largest indoor cannabis producing countries in Europe. In both countries, legal prosecution procedure of convicted illicit cannabis growers usually includes recovery of the profits gained. However, it is not easy to make a reliable estimation of the latter profits, due to the wide range of factors that determine indoor cannabis yields and eventual selling prices. In the Netherlands, since 2005, a reference model is used that assumes a constant yield (g) per plant for a given indoor cannabis plant density. Later, in 2011, a new model was developed in Belgium for yield estimation of Belgian indoor cannabis plantations that assumes a constant yield per m(2) of growth surface, provided that a number of growth conditions are met. Indoor cannabis plantations in the Netherlands and Belgium share similar technical characteristics. As a result, for indoor cannabis plantations in both countries, both aforementioned yield estimation models should y...

African Journal of Ecology, 2016

The Mbanza-Ngungu region (Kongo-Central province, DRC) currently faces continued forest deteriora... more The Mbanza-Ngungu region (Kongo-Central province, DRC) currently faces continued forest deterioration. Many of these forests were traditionally protected areas of which to date, only traces are left. The aim of this study was to evaluate and compare the importance of forest remnants and other components of the landscape for the collection of medicinal plants in the Mbanza-Ngungu Region, DRC. Between February 2009 and May 2012, semi-structured interviews and participatory observations were conducted in this region with 51 traditional healers selected by means of the ‘snowball method’. Local importance of medicinal plants was determined by the medicinal Use Value parameter. Statistical analyses were carried out with SPSS 20.0 and based on chi-square test, analysis of variance and post hoc comparison of means. Our results show that the forest remnants remain the main medicinal species provider: 68 species against 62 for agro-ecosystems. However, the total number of citations for medicinal species uses is higher for agro-ecosystems (293) than for forest remnants (233), and this difference is significant (P < 0·05). This could be explained, among others, by the fact that some forest remnants are respected or protected by the villagers for religious and ritual purposes (Sangi). This also points to the importance of agro-ecosystems and secondary vegetation as provider of medicinal plants around rural villages, as seen elsewhere in the tropics. Resume La region de Mbanza-Ngungu (Province du Kongo-Central, RDC) subit actuellement une deterioration continue de ses forets. Une grande partie de ces forets etaient traditionnellement des aires protegees mais il n'en reste aujourd'hui que quelques traces. Le but de cette etude etait d’evaluer et de comparer l'importance des vestiges forestiers et d'autres composantes du paysage pour la collecte de plantes medicinales dans la region de Mbanza-Ngungu. Entre fevrier 2009 et mai 2012, nous avons realise des interviews semi-structurees et des observations participatives dans la region avec 51 guerisseurs traditionnels avec la methode « boule de neige ». L'importance locale des plantes medicinales fut determinee au moyen du parametre Valeur d'usage. Les analyses statistiques furent faites avec SPSS 20.0 et basees sur un test de χ², une analyse de la variance et une comparaison post hoc des moyennes. Nos resultats montrent que les vestiges de forets restent les principaux pourvoyeurs d'especes medicinales : 68 especes pour 62 dans les ecosystemes agricoles. Cependant, le nombre total de citations pour l'usage d'especes medicinales est plus eleve pour ces derniers (293) que pour les vestiges de forets (233), et cette difference est significative (P < 0.05). Ceci pourrait s'expliquer notamment par le fait que certains vestiges forestiers sont respectes ou proteges par les villageois pour des raisons religieuses ou rituelles (Sangi). Ceci souligne aussi l'importance des ecosystemes agricoles et de la vegetation secondaire comme sources de plantes medicinales aux environs des villages ruraux, comme ailleurs sous les tropiques.

International Journal of Environmental Research and Public Health

Agroforestry

Multistrata agroforests comprise a wide range of agroforestry practices that includes assemblage ... more Multistrata agroforests comprise a wide range of agroforestry practices that includes assemblage of woody and nonwoody plant components, with the wide range of practices on the continuum from using shade trees in perennial plantation to very diversified agroforests that mimic the original forest-like structure. In the humid tropical lowlands, such systems often consist of cocoa (Theobroma cacao) grown under the shade of trees. In this review, we explore the reliability of research on and the feasibility of achieving the environmental and economic benefits of cocoa agroforests, highlighting future opportunities and challenges of cocoa growing. Unsustainable intensification in a form of monocultures with high agricultural inputs reduces ecological resilience of a land-use system, whereas paradoxically, environmental and climate changes require more than ever a higher capacity of land-use systems to cope with increasing global environmental pressure. Over the past decade, a number of new studies focusing on cocoa agroforests have been published. We review current cultivation of cocoa in the world and outline the establishment and management of cocoa agroforests. Further on, we explored the idea that cocoa agroforests could be a solution to prevent phenomenon of boom-and-bust cycle of cocoa cultivation and highlighted the possibilities for improvement of cocoa cultivation using its vast genetic base. Then the benefits of cocoa agroforests for (agro)biodiversity and soil conservation are summarized and economic perspectives of multistrata systems assessed. In final discussion, we performed a SWOT analysis, highlighting future opportunities and challenges and proposing recommendation to improve the extension, adoption and sustainability of cocoa agroforests.

Acta Horticulturae

Abstract: Cherimoya (Annona cherimola Mill.) is an exquisite subtropical fruit, intensively culti... more Abstract: Cherimoya (Annona cherimola Mill.) is an exquisite subtropical fruit, intensively cultivated in Spain, but generally underutilized in the inter-Andean valleys where the species shows high botanical diversity. Economic use of Andean cherimoyas currently remains far below potential levels. In 2006-2007, a cherimoya value chain analysis was performed through a market survey in which structured interviews were made with 172 cherimoya producers and 346 cherimoya traders in Ecuador, Peru, and Bolivia. Two main ...

Tropical Conservation Science

BMC Complementary and Alternative Medicine, 2015

Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen), 2001

Journal of Applied Entomology, 2015

ABSTRACT The cocoa pod borer (CPB), Conopomorpha cramerella (Snellen), sex pheromone was previous... more ABSTRACT The cocoa pod borer (CPB), Conopomorpha cramerella (Snellen), sex pheromone was previously identified as a blend of (E,Z,Z)- and (E,E,Z)-4,6,10-hexadecatrienyl acetates and corresponding alcohols. These pheromone components were synthesized by modification of an existing method and the relative attractiveness of synthetic blends that included different levels of non-target pheromone components and chemical purities was tested in a cocoa field using Delta traps. Male captures were not significantly different among traps baited with pheromone blends containing 5% to 47% (based on four identified pheromone components) of other geometric acetates [(E,Z,E)-, (Z,Z,Z)-, (Z,E,Z)- and (Z,E,E)-4,6,10-hexadecatrienyl acetates], indicating that C. cramerella males did not discriminate among the pheromone components and other geometric isomers in the blends. Therefore, neither antagonistic nor synergistic effects from other pheromone geometric isomers were observed. The modified synthetic pathway offers the prospect of more economical production of CPB sex pheromone. During 17 weeks when C. cramerella monitoring coincided with the main cocoa pod harvest period in 2013–2014, CPB trap catch data from some blends showed a good correlation with the number of pods with C. cramerella infestation symptoms.

Center for Sustainable Development (CDO), Ghent University, 2004

The concept of ecological debt was coined by southern NGOs at the beginning of the 1990s. It usua... more The concept of ecological debt was coined by southern NGOs at the beginning of the 1990s. It usually refers to the ecological damage caused by industrialized countries to the southern hemisphere and/or to the use of ecosystem services at the expense of southern-hemisphere countries. Currently, several NGO networks from north and south are campaigning for the recognition of the concept. In Belgium, the concept made its way into the first Federal Plan for Sustainable Development 2001-2004, which explicitly states that" Belgium will study ...

Executive Summary The aim of the research project 'Elaboration of the Concept of Ecological ... more Executive Summary The aim of the research project 'Elaboration of the Concept of Ecological Debt'was to clarify the concept of ecological debt (state of affairs, definition, methodology, scientific frame of reference) and to study its relevance and applicability in Belgian and international policy. The research project focused on the ecological debt of countries and the consequences of this debt, such as the policy consequences on national level or in international negotiations. The question of ecological debt of companies was ...

The International journal on drug policy, 2014

As a result of increased pressure on cannabis cultivation in The Netherlands, the number of confi... more As a result of increased pressure on cannabis cultivation in The Netherlands, the number of confiscated indoor cannabis plantations in Belgium is rising. Although increases are reported for all plantations sizes, half of the seized plantations contain less than 50 plants. In this study, factors and variables that influence costs and benefits of indoor cannabis cultivation are investigated as well as how these costs and benefits vary between different cannabis grower types. Real-situation data of four growers were used to perform financial analyses. Costs included fixed and variable material costs, as well as opportunity costs. Gross revenue per grow cycle was calculated based on most recent forensic findings for illicit Belgian cannabis plantations and was adjusted for the risk of getting caught. Finally, gross revenues and return on costs (ROC) were calculated over 1 year (4 cycles). Financial analysis shows that in all cases gross revenues as well as ROC are considerable, even aft...

Family Physician Perceptions of Climate Change, Migration, Health, and Healthcare in Sub-Saharan Africa: An Exploratory Study, 2021

Although family physicians (FPs) are community-oriented primary care generalists and should be th... more Although family physicians (FPs) are community-oriented primary care generalists and
should be the entry point for the population’s interaction with the health system, they are underrepresented
in research on the climate change, migration, and health(care) nexus (hereafter referred to as
the nexus). Similarly, FPs can provide valuable insights into building capacity through integrating
health-determining sectors for climate-resilient and migration-inclusive health systems, especially in
Sub-Saharan Africa (SSA). Here, we explore FPs’ perceptions on the nexus in SSA and on intersectoral
capacity building. Three focus groups conducted during the 2019 WONCA-Africa conference in
Uganda were transcribed verbatim and analyzed using an inductive thematic approach. Participants’
perceived interactions related to (1) migration and climate change, (2) migration for better health and
healthcare, (3) health impacts of climate change and the role of healthcare, and (4) health impacts of
migration and the role of healthcare were studied. We coined these complex and reinforcing interactions
as continuous feedback loops intertwined with socio-economic, institutional, and demographic
context. Participants identified five intersectoral capacity-building opportunities on micro, meso,
macro, and supra (international) levels: multi-dimensional and multi-layered governance structures;
improving FP training and primary healthcare working conditions; health advocacy in primary
healthcare; collaboration between the health sector and civil society; and more responsibilities for
high-income countries. This exploratory study presents a unique and novel perspective on the nexus
in SSA which contributes to interdisciplinary research agendas and FP policy responses on national,
regional, and global levels.

A B S T R A C T Together, the Netherlands and Belgium are the largest indoor cannabis producing c... more A B S T R A C T Together, the Netherlands and Belgium are the largest indoor cannabis producing countries in Europe. In both countries, legal prosecution procedure of convicted illicit cannabis growers usually includes recovery of the profits gained. However, it is not easy to make a reliable estimation of the latter profits, due to the wide range of factors that determine indoor cannabis yields and eventual selling prices. In the Netherlands, since 2005, a reference model is used that assumes a constant yield (g) per plant for a given indoor cannabis plant density. Later, in 2011, a new model was developed in Belgium for yield estimation of Belgian indoor cannabis plantations that assumes a constant yield per m 2 of growth surface, provided that a number of growth conditions are met. Indoor cannabis plantations in the Netherlands and Belgium share similar technical characteristics. As a result, for indoor cannabis plantations in both countries, both aforementioned yield estimation models should yield similar yield estimations. By means of a real-case study from the Netherlands, we show that the reliability of both models is hampered by a number of flaws and unmet preconditions. The Dutch model is based on a regression equation that makes use of ill-defined plant development stages, assumes a linear plant growth, does not discriminate between different plantation size categories and does not include other important yield determining factors (such as fertilization). The Belgian model addresses some of the latter shortcomings, but its applicability is constrained by a number of preconditions including plantation size between 50 and 1000 plants; cultivation in individual pots with peat soil; 600 W (electrical power) assimilation lamps; constant temperature between 20 C and 30 C; adequate fertilizer application and plants unaffected by pests and diseases. Judiciary in both the Netherlands and Belgium require robust indoor cannabis yield models for adequate legal prosecution of illicit indoor cannabis growth operations. To that aim, the current models should be optimized whereas the validity of their application should be examined case by case.

Vascular streak dieback (VSD), caused by Ceratobasidium theobromae (P.H.B. Talbot & Keane), has a... more Vascular streak dieback (VSD), caused by Ceratobasidium theobromae (P.H.B. Talbot & Keane), has a considerable impact on cacao (Theobroma cacao L.) production in Southeast Asia. Two biocontrol experiments were set up to explore alternatives to ineffective chemical control of VSD. The effects on VSD development of (i) Trichoderma harzianum, superficially applied to leaves of mature cacao plants, and (ii) an inoculation with fungal (Trichoderma asperellum) and bacterial (Bacillus sp., Pseudomonas sp. and Enterobacter spp.) elicitors of systemic resistance in young cacao plants, were tested. After three months, cacao leaves treated with T. harzianum exhibited a significantly (p < .05) lower disease score compared to the untreated control leaves, with no significant differences or interaction effects between three cacao clones tested. Six months after inoculation of cacao seedlings with elicitors, a significant (p < .05) effect on the number of VSDaffected leaves per plant was evidenced on seedlings treated with Bacillus sp. and Enterobacter spp. After transplanting to the field (8 months after inoculation), both number of VSD-affected leaves per plant and number of VSD-affected leaves per branch per plant were significantly (p < .05) lower as compared to control plants following inoculation by all bacterial elicitors tested, with no significant differences in the VSD controlling effect observed between the different bacterial elicitors tested. T. asperellum did not show potential as an elicitor of systemic resistance in our experiment. More research is needed on the lasting effect of biocontrol treatments, as well as on their economic and ecological sustainability.