Stream Productivity by Outermost Termination

Streams are infinite sequences over a given data type. A stream specification is a set of equations intended to define a stream. A core property is productivity: unfolding the equations produces the intended stream in the limit. In this paper we show that productivity is equivalent to termination with respect to the balanced outermost strategy of a TRS obtained by adding an additional rule. For specifications not involving branching symbols balancedness is obtained for free, by which tools for proving outermost termination can be used to prove productivity fully automatically

Understanding the Role of Nature in Urban-Rural Linkages: Identifying the Potential Role of Rural Nature-Based Attractive Clusters That Serve Human Well-Being

Rural areas provide unique amenities for recreational purposes which are highly appreciated by urban inhabitants. This generates an important but often hidden relationship between the urban and the rural. The aim of our study is first to provide empirical evidence for this linkage and then to identify for Italy, at the municipal level, those rural areas which actually function as nature-based attractive clusters. We used the data coming from a participatory webGIS survey that asked 1632 Italian respondents to mark attractive nature related places locally, regionally, nationally and world-wide to explain quantitatively and qualitatively the relationship between urban and rural. From the survey, indicators were developed to rank the nature-based attractive clusters. Our results pointed out a major (almost double) flow from urban to rural for natural amenities, which increased with the spatial level at which attractive nature areas were marked. This analysis allowed for the identification rural clusters of Italian municipalities that form nodal points for nature-based urban well-being; shedding light on an often neglected urban-rural relationship. The method is applicable in other countries and may stimulate better planning and management strategies for improving rural areas, taking an urban-rural perspective

Psychometric properties of an instrument to measure the clinical learning environment

Objectives: The clinical learning environment is an influential factor in work-based learning. Evaluation of this environment gives insight into the educational functioning of clinical departments. The Postgraduate Hospital Educational Environment Measure (PHEEM) is an evaluation tool consisting of a validated questionnaire with 3 subscales. In this paper we further investigate the psychometric properties of the PHEEM. We set out to validate the 3 subscales and test the reliability of the PHEEM for both clerks (clinical medical students) and registrars (specialists in training). Methods: Clerks and registrars from different hospitals and specialties filled out the PHEEM. To investigate the construct validity of the 3 subscales, we used an exploratory factor analysis followed by varimax rotation, and a cluster analysis known as Mokken scale analysis. We estimated the reliability of the questionnaire by means of variance components according to generalisability theory. Results: A total of 256 clerks and 339 registrars filled out the questionnaire. The exploratory factor analysis plus varimax rotation suggested a 1-dimensional scale. The Mokken scale analysis confirmed this result. The reliability analysis showed a reliable outcome for 1 department with 14 clerks or 11 registrars. For multiple departments 3 respondents combined with 10 departments provide a reliable outcome for both groups. Discussion: The PHEEM is a questionnaire measuring 1 dimension instead of the hypothesised 3 dimensions. The sample size required to achieve a reliable outcome is feasible. The instrument can be used to evaluate both single and multiple departments for both clerks and registrars. © 2007 Blackwell Publishing Ltd

Tracked to protect - Spatiotemporal dynamics of recreational boating in sensitive marine natural areas

In many coastal areas, high numbers of recreationists may exceed ecological capacities. Careful monitoring of visitor flows is a first prerequisite for coastal area management. We show how AIS ship data can be translated into interpretable information on recreational boats and investigate whether AIS can provide monitoring information when compared to nature conservation policy targets. In the Wadden Sea UNESCO World Heritage Site we used nearly 9 million data points to create spatiotemporal patterns for the 2018 recreation season. We combined this with shipping lanes and bathymetry data and compared the resulting patterns with nature protection regulations. Our results show that most of the traffic is concentrated around tidal channels. We also show that exceeding speed limits is not predominant behaviour, but the effect of speeding on birds and seals might be more severe than the data suggests. We mapped favourite tidal flat moor activities, and observed where this occurs in Marine Protected Areas. We conclude that AIS analysis can provide valuable recreational boating monitoring, relevant to sensitive coastal area management in the entire Dutch Wadden Sea for the full recreational season. Broader integration of AIS with radar data and ecological data can add to the power of using AIS

Modelgebruik in de Natuurverkenning 2010-2040

Modellen spelen in de Natuurverkenning 2010-2040 een belangrijke rol bij het uitwerken en doorrekenen van toekomstscenario’s. Waar eerdere verkenningen gebruik maakten van procesmodellen om effecten van omgevingsscenario's door te rekenen, zijn nu met eenvoudige modellen de gevolgen van normatieve opvattingen of wensbeelden ten aanzien van natuur in beeld gebracht. Dit artikel beschrijft deze nieuwe toepassing van modellen en evalueert de meerwaarde ten opzichte van de aanpak in eerdere verdenningen

An aeroacoustic investigation into the effect of self-oscillating trailing edge flaplets

The aeroacoustics of a NACA 0012 aerofoil with an array of self-oscillating flexible flaplets attached on the trailing edge has been investigated at low to moderate chord based Reynolds number (50,000 -- 350,000) and at geometric angles of attack from $\alpha_g = 0^\circ$ -- $20^\circ$. When the aerofoil is untripped, tonal peaks are observed on the baseline aerofoil. When the passive flaplets are attached to the pressure side of the aerofoil, the tonal peak is removed. If the flaplets are then placed on the suction side, the tonal peak is reduced, but not removed. It is therefore hypothesised that the flaplets on the pressure side modifies the laminar separation bubble situated on the pressure side of the aerofoil, a key mechanism for tonal noise. Throughout all cases, both tripped and untripped, a low frequency (0.1 kHz -- 0.6 kHz) noise reduction and a slight increase at higher frequencies (>2 kHz) is seen. This gives an average overall sound pressure level (OSPL) reduction of 1.5 -- 2 dB for the flaplets affixed to the pressure side. The cases where the tonal noise component is removed an OSPL reduction of up to 20 dB can be seen

Maintaining natural and traditional cultural green infrastructures across Europe: learning from historic and current landscape transformations

CONTEXT: Maintaining functional green infrastructures (GIs) require evidence-based knowledge about historic and current states and trends of representative land cover types. OBJECTIVES: We address: (1) the long-term loss and transformation of potential natural forest vegetation; (2) the effects of site productivity on permanent forest loss and emergence of traditional cultural landscapes; (3) the current management intensity; and (4) the social-ecological contexts conducive to GI maintenance. METHODS: We selected 16 case study regions, each with a local hotspot landscape, ranging from intact forest landscapes, via contiguous and fragmented forest covers, to severe forest loss. Quantitative open access data were used to estimate (i) the historic change and (ii) transformation of land covers, and (iii) compare the forest canopy loss from 2000 to 2018. Qualitative narratives about each hotspot landscape were analysed for similarities (iv). RESULTS: While the potential natural forest vegetation cover in the 16 case study regions had a mean of 86%, historically it has been reduced to 34%. Higher site productivity coincided with transformation to non-forest land covers. The mean annual forest canopy loss for 2000–2018 ranged from 0.01 to 1.08%. The 16 case studies represented five distinct social-ecological contexts (1) radical transformation of landscapes, (2) abuse of protected area concepts, (3) ancient cultural landscapes (4) multi-functional forests, and (5) intensive even-aged forest management, of which 1 and 4 was most common. CONCLUSIONS: GIs encompass both forest naturalness and traditional cultural landscapes. Our review of Pan-European regions and landscapes revealed similarities in seemingly different contexts, which can support knowledge production and learning about how to sustain GIs

Natuurverkenning 2010-2040 : visies op de ontwikkeling van natuur en landschap

De Natuurverkenning verschijnt in een turbulente tijd waarin natuur en landschap sterk gepolitiseerd zijn. Met de verkenning wil het PBL een bijdrage leveren aan het structureren van het debat over de vernieuwing van het langetermijnbeleid en een impuls geven aan de politieke afwegingen. Nieuw is het gebruik van normatieve toekomstscenario’s als hulpmiddel om de achterliggende drijfveren voor natuurbeleid te verhelderen