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Brock O.,Netherlands Institute for Neuroscience | Brock O.,Group 47 | Bakker J.,Netherlands Institute for Neuroscience | Bakker J.,VU University Amsterdam | Bakker J.,University of Liege
Endocrinology | Year: 2013

In rodents, kisspeptin-expressing neurons are localized in 2 hypothalamic brain nuclei (anteroventral periventricular nucleus/periventricular nucleus continuum [AVPv/PeN] and arcuate nucleus [ARC]) and modulated by sex steroids. By using wild-type (WT) and aromatase knockout (ArKO) mice (which cannot convert testosterone into estradiol) and immunohistochemistry, we observed that WT females showed a continuous increase in kisspeptin peptide expression in the ARC across postnatal ages (postnatal day 5 [P5] to P25), whereasWTmales did not show any expression before P25. Kisspeptin peptide expression was also present in ArKO females but did not increase over this early postnatal period, suggesting that kisspeptin peptide expression in the ARC is organized by estradiol-dependent and -independent mechanisms. We also compared kisspeptin peptide expression between groups of adult male and female mice that were left gonadally intact or gonadectomized and treated or not with estradiol (E2) or DHT. In the ARC, kisspeptin peptide expression decreased after gonadectomy but was completely rescued by either E2 or DHT treatment in each sex/genotype. However, kisspeptin peptide expression was lower in ArKO compared withWT subjects. In the AVPv/PeN, ArKO females showed a male-typical kisspeptin peptide expression, and adult E2 treatment partially restored kisspeptin peptide expression. Finally, we showed that, after E2 treatment ofWTand ArKO mice between either P5 and P15 or P15 and P25, AVPv/PeN kisspeptin peptide expression could be still masculinized at P5, but was feminized from P15 onward. In conclusion, the 2 kisspeptin neuronal populations (AVPv/PeN vs ARC) seem to be differentially organized and activated by E2. © 2013 by The Endocrine Society. Source


Vaessen C.,Group 47
Journal of visceral surgery | Year: 2011

The advent of robot-assisted surgery is a surgical revolution. However, the costs of installing and using a da Vinci system are impediments to the proliferation of this technology. This article reviews the locations of robotic surgical systems worldwide and in France, in 2010. Copyright © 2011. Published by Elsevier Masson SAS. Source


Arnouts R.,Wageningen University | van der Zouwen M.,KWR Watercycle Research Institute | Arts B.,Group 47
Forest Policy and Economics | Year: 2012

Governance is one of the most frequently discussed issues in contemporary policy science literature, and this has led to a wide variety of conceptualisations. However, few of these offer a typology that can be used to actually analyse governance. In this paper, we present such a typology. We distinguish governance modes and governance shifts and use Kooiman's governance conception as our main inspiration, elaborated with the help of the policy arrangement approach. This results in four ideal-type governance modes - hierarchical, closed co-, open co- and self governance - that are operationalised into four ideal-type governance arrangements. These arrangements differ from one another in terms of actors, power and interaction rules. In explaining governance shifts, we distinguish between old and new modes of governance and introduce three external change factors (adjacent policy arrangements, socio-political trends and shock events) and one internal factor (policy entrepreneurs) that can account for governance change. To prove the value of our framework, we apply it to a case, i.e. the rise of nature policy in the Dutch region Utrechtse Heuvelrug in the 1970s and 1980s. Besides providing insight into how to work with our framework, the results also reveal a rather paradoxical governance shift, i.e. from a new to an old mode, thus putting the much heralded shift "from government to governance" into perspective. © 2011 Elsevier B.V. Source


Van Atteveldt N.,Group 47 | Van Atteveldt N.,VU University Amsterdam | Van Atteveldt N.,Maastricht University | Murray M.M.,University of Lausanne | And 4 more authors.
Neuron | Year: 2014

Research into the anatomical substrates and "principles" for integrating inputs from separate sensory surfaces has yielded divergent findings. This suggests that multisensory integration is flexible and context dependent and underlines the need for dynamically adaptive neuronal integration mechanisms. We propose that flexible multisensory integration can be explained by a combination of canonical, population-level integrative operations, such as oscillatory phase resetting and divisive normalization. These canonical operations subsume multisensory integration into a fundamental set of principles as to how the brain integrates all sorts of information, and they are being used proactively and adaptively. We illustrate this proposition by unifying recent findings from different research themes such as timing, behavioral goal, and experience-related differences in integration. van Atteveldt etal. discuss how the flexible, context-dependent manifestations of multisensory integration can be explained by adaptive and proactive interplay of canonical neural operations for cue integration, such as oscillatory phase resetting and divisive normalization. © 2014 Elsevier Inc. Source


Population genetic studies focus on natural dispersal and isolation by landscape barriers as the main drivers of genetic population structure. However, anthropogenic factors such as reintroductions, translocations and wild x domestic hybridization may also have strong effects on genetic population structure. In this study we genotyped 351 Single Nucleotide Polymorphism markers evenly spread across the genome in 645 wild boar (Sus scrofa) from Northwest Europe to evaluate determinants of genetic population structure. We show that wild boar genetic population structure is influenced by historical reintroductions and by genetic introgression from domestic pigs. Six genetically distinct and geographically coherent wild boar clusters were identified in the Netherlands and Western Germany. The Dutch Veluwe cluster is known to be reintroduced, and three adjacent Dutch and German clusters are suspected to be a result of reintroduction, based on clustering results, low levels of heterozygosity and relatively high genetic distances to nearby populations. Recent wild x domestic hybrids were found geographically widespread across clusters and at low frequencies (average 3.9%). The relationship between pairwise kinship coefficients and geographic distance showed male-biased dispersal at the population genetic level. Our results demonstrate that wildlife and landscape management by humans are shaping the genetic diversity of an iconic wildlife species. Historical reintroductions, translocation and recent restocking activities with farmed wild boar have all influenced wild boar genetic population structure. The current trend of wild boar population growth and range expansion has recently led to a number of contact zones between clusters, and further admixture between the different wild boar clusters is to be expected. Source

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