Testing quantised inertia on galactic scales

Galaxies and galaxy clusters have rotational velocities apparently too fast to allow them to be gravitationally bound by their visible matter. This has been attributed to the presence of invisible (dark) matter, but so far this has not been directly detected. Here, it is shown that a new model that modifies inertial mass by assuming it is caused by Unruh radiation, which is subject to a Hubble-scale (Theta) Casimir effect predicts the rotational velocity (v) to be: v^4=2GMc^2/Theta (the Tully-Fisher relation) where G is the gravitational constant, M is the baryonic mass and c is the speed of light. The model predicts the outer rotational velocity of dwarf and disk galaxies, and galaxy clusters, within error bars, without dark matter or adjustable parameters, and makes a prediction that local accelerations should remain above 2c^2/Theta at a galaxy's edge.Comment: 7 pages, 1 figure. Accepted for publication in Astrophysics and Space Science on 27/7/201

Provinciaal natuurbeleid: kwaliteitsdoelen voor de ecologische hoofdstructuur

Ingegaan wordt op 'natuurgebiedsplannen en beheersgebieden', 'gewenste grond- en oppervlaktewaterregime (GGOR). Verslag voor het Natuurplanbureau', ' reconstructie van de varkenshouderij' en 'de habitat- en vogelrichtlijn' . Bevat tevens intervviews met deskundigen in de provincies en het resultaat van hun ronde tafel overleg (31 mei 2001). Verslag voor het Natuurplanburea

Breaking boundaries for biodiversity : expanding the policy agenda to halt biodiversity loss

Our assessment from the perspective of the Netherlands, a country in the temperate zone, showed a slightly positive picture, in line with the overall results for this zone. The loss of biodiversity in the Netherlands has been slowed down, but the European target – halting the loss of biodiversity – could not be met. The picture in the Netherlands is less positive if the average low quality of the remaining Dutch biodiversity is taken into account. If the impacts on biodiversity abroad of imports into the Netherlands are also included, we conclude that the Netherlands is not succeeding in slowing down the loss of biodiversity

A generic problem with purely metric formulations of MOND

We give a simple argument to show that no purely metric-based, relativistic formulation of Milgrom's Modified Newtonian Dynamics (MOND) whose energy functional is stable (in the sense of being quadratic in perturbations) can be consistent with the observed amount of gravitational lensing from galaxies. An important part of the argument is the fact that reproducing the MOND force law requires any completely stable, metric-based theory of gravity to become conformally invariant in the weak field limit. We discuss the prospects for a formulation with a very weak instability.Comment: 4 pages, revtex4, no figure

Modified gravity without dark matter

On an empirical level, the most successful alternative to dark matter in bound gravitational systems is the modified Newtonian dynamics, or MOND, proposed by Milgrom. Here I discuss the attempts to formulate MOND as a modification of General Relativity. I begin with a summary of the phenomenological successes of MOND and then discuss the various covariant theories that have been proposed as a basis for the idea. I show why these proposals have led inevitably to a multi-field theory. I describe in some detail TeVeS, the tensor-vector-scalar theory proposed by Bekenstein, and discuss its successes and shortcomings. This lecture is primarily pedagogical and directed to those with some, but not a deep, background in General RelativityComment: 28 pages, 10 figures, lecture given at Third Aegean Summer School, The Invisible Universe: Dark Matter and Dark Energy, minor errors corrected, references update

The Pioneer anomaly and the holographic scenario

In this paper we discuss the recently obtained relation between the Verlinde's holographic model and the first phenomenological Modified Newtonian dynamics. This gives also a promising possible explanation to the Pioneer anomaly.Comment: 5 pages, Accepted for publication in Astrophysics & Space Scienc

Beleidsevaluatie agrarisch natuurbeheer : voortgang, knelpunten eneffectiviteit

Evaluatie van Natuurplanburea

Voortgang realisatie natuurnetwerk : technische achtergronden bij de digitale Balans van de Leefomgeving 2018

Om de achteruitgang in biodiversiteit en het areaal natuur te stoppen en weer te herstellen, werkt de overheid met haar partners in Nederland aan de realisatie van een samenhangend netwerk van bestaande en nieuw te ontwikkelen grotere natuurgebieden. Het Rijk wil graag op de hoogte blijven van de vorderingen van dit beleid. Het Planbureau voor de Leefomgeving (PBL) heeft daarom indicatoren geselecteerd die een antwoord geven op de vraag: “Wat zijn de vorderingen van het natuurbeleid, met name op het gebied van de realisatie van het natuurnetwerk?” De indicatoren zijn geactualiseerd en geanalyseerd om de voortgang van het natuurbeleid tussentijds te evalueren. Dit rapport beschrijft de resultaten van het beleid aan de hand van de indicatoren, de technische achtergronden van de gebruikte gegevens en methoden voor de actualisatie van deze indicatoren en de betrouwbaarheid en aannemelijkheid daarvan.---The Dutch government and its partners are taking measures to create a coherent network of protected areas in order to halt the decline in biodiversity and in the area of natural habitat and semi-natural habitat, and to improve the conservation status of these areas. The government wants to stay informed of the progress being made. The Netherlands Environmental Assessment Agency (PBL) has selected indicators that should provide answers to the question: ‘What progress is being made with the measures being taken to establish the national ecological network?’ The selected indicators have been updated and analysed in order to assess this progress. This report describes the results of the policy measures taken on the basis of the indicators, the technical background of the data used, the methods used to bring these indicators up to date, and the reliability and plausibility of the results

Deformations of quantum field theories on spacetimes with Killing vector fields

The recent construction and analysis of deformations of quantum field theories by warped convolutions is extended to a class of curved spacetimes. These spacetimes carry a family of wedge-like regions which share the essential causal properties of the Poincare transforms of the Rindler wedge in Minkowski space. In the setting of deformed quantum field theories, they play the role of typical localization regions of quantum fields and observables. As a concrete example of such a procedure, the deformation of the free Dirac field is studied.Comment: 35 pages, 3 figure

Het biodiversiteitsbeleid in Nederland werkt : achtergronddocument bij Balans van de leefomgeving

Dit WOt-werkdocument beschrijft materiaal en methoden van de resultaten uit de beleidsstudie en bevat uitgebreide achtergrondinformatie, theorie en uitleg dan het PBLachtergronddocument van de Balans van de Leefomgeving. Het doel van dit aanvullende WOt-werkdocument is de kwaliteitsborging van de door de WOT Natuur & Milieu, onderdeel van Wageningen UR ingebrachte onderdelen van de volgende drie PBL-documenten: •¿De Balans van de Leefomgeving (hoofdstuk 6: Biodiversiteit); •¿Evaluatie biodiversiteitdoelstelling 2010, achtergronddocument bij de Balans van de Leefomgeving 2010 (hoofdstuk 2: Biodiversiteit in Nederland); •¿Breaking boundaries for biodiversity. Expanding the policy agenda to halt biodiversity loss