Beyond walking and cycling: scoping small-wheel modes

Active travel beyond walking and cycling – by small-wheel modes such as inline skating, skateboarding and push scooting, among others – needs more understanding in terms of the design, maintenance and management issues it may present in the future. These modes – especially their use for travel rather than leisure pursuits – are rarely quantified outside of accident statistics and the focus of qualitative study in the governance of public space conflict or the sociology of childhood activities. This paper reports on a scoping study exploring the potential for small-wheel modes among other means of ‘human locomotion’. The study first recruited local transport officers and people using these modes, as well as academic experts. The study found that there are differences between the views of planning officers and users of these modes that need to be investigated further to arrive at solid conclusions and advice for the design, maintenance and management issues needed both now and in a future that allows more variety and choice in human locomotion for active travel. The use of user-generated digital data for data capture, analysis and mapping was also explored

Modelling and validation techniques for bottom-up housing stock modelling of non-heating end-use energy in England

This thesis engages with different methods and validation techniques for bottom-up stock modelling of non-heating end-use energy of the residential sector. These end-uses are not the primary focus of current domestic energy models, and there is a unique opportunity to use actual electricity use data to build and validate models as electricity becomes exclusively used for these end-uses in England. The first contribution to knowledge is the creation of a validation set from aggregated electricity use data that has become available from small census areas of around 600 households using only areas with minimal estimated rates of electric heating. The second contribution is a method for using partial data from recent housing and energy surveys to update complete, but dated surveys by using household size and seasonal distributions. This enables a yearly updated model validated against actual aggregate energy use. This led to an annually updateable single-level model of non-heating end-use energy based on the predictors of household size measured by the number of rooms and the number of occupants. This uses linear regression on a square-root transformation of energy instead of the current natural logarithm transformation. The model is found to have a slight over-prediction (1.5%) of energy use when validated. The final contribution is an alternative approach where the model was allowed to vary on the household’s area. A hierarchical linear model of domestic energy was built based on 20 area classifications. There is a weak, but significant effect of additional energy use in households located inside area classifications with higher mean household sizes. This effect is highly significant when building age is taken into account. Although validation was difficult because building age data is limited, this result points to a neighbourhood-level influence that explains energy use beyond individual household size if precise location data can be made available

Large-scale synchrony of gap dynamics and the distribution of understory tree species in maple-beech forests

Large-scale synchronous variations in community dynamics are well documented for a vast array of organisms, but are considerably less understood for forest trees. Because of temporal variations in canopy gap dynamics, forest communities—even old-growth ones—are never at equilibrium at the stand scale. This paucity of equilibrium may also be true at the regional scale. Our objectives were to determine (1) if nonequilibrium dynamics caused by temporal variations in the formation of canopy gaps are regionally synchronized, and (2) if spatiotemporal variations in canopy gap formation aVect the relative abundance of tree species in the understory. We examined these questions by analyzing variations in the suppression and release history of Acer saccharum Marsh. and Fagus grandifolia Ehrh. from 481 growth series of understory saplings taken from 34 mature stands. We observed that (1) the proportion of stems in release as a function of time exhibited a U-shaped pattern over the last 35 years, with the lowest levels occurring during 1975–1985, and that (2) the response to this in terms of species composition was that A. saccharum became more abundant at sites that had the highest proportion of stems in release during 1975–1985. We concluded that the understory dynamics, typically thought of as a stand-scale process, may be regionally synchronized

Patterns and drivers of tree Mortality in Iberian Forests: climatic effects are modified by competition

Tree mortality is a key process underlying forest dynamics and community assembly. Understanding how tree mortality is driven by simultaneous drivers is needed to evaluate potential effects of climate change on forest composition. Using repeat-measure information fromc.400,000 trees from the Spanish Forest Inventory, we quantified the relative importance of tree size, competition, climate and edaphic conditions on tree mortality of 11 species, and explored the combined effect of climate and competition. Tree mortality was affected by all of these multiple drivers, especially tree size and asymmetric competition, and strong interactions between climate and competition were found. All species showed L-shaped mortality patterns (i.e. showed decreasing mortality with tree size), but pines were more sensitive to asymmetric competition than broadleaved species. Among climatic variables, the negative effect of temperature on tree mortality was much larger than the effect of precipitation. Moreover, the effect of climate (mean annual temperature and annual precipitation) on tree mortality was aggravated at high competition levels for all species, but especially for broadleaved species. The significant interaction between climate and competition on tree mortality indicated that global change in Mediterranean regions, causing hotter and drier conditions and denser stands, could lead to profound effects on forest structure and composition. Therefore, to evaluate the potential effects of climatic change on tree mortality, forest structure must be considered, since two systems of similar composition but different structure could radically differ in their response to climatic conditions

The Confrontation between General Relativity and Experiment

The status of experimental tests of general relativity and of theoretical frameworks for analysing them are reviewed. Einstein's equivalence principle (EEP) is well supported by experiments such as the E\"otv\"os experiment, tests of special relativity, and the gravitational redshift experiment. Future tests of EEP and of the inverse square law will search for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, and the Nordtvedt effect in lunar motion. Gravitational wave damping has been detected to half a percent using the binary pulsar, and new binary pulsar systems may yield further improvements. When direct observation of gravitational radiation from astrophysical sources begins, new tests of general relativity will be possible.Comment: 103 pages, 10 figures, accepted for publication in Living Reviews in Relativit

Impacts of soil conditions and light availability on natural regeneration of Norway spruce Picea abies (L.) H. Karst. in low-elevation mountain forests

& Key message Natural regeneration of P. abies (L.) H. Karst. may reach high densities in lower mountain elevations. The highest densities were found in sites with moderate light availability, with low pH, and not near the riverbank. However, age-height classes differed in the predicted magnitude of response, but were consistent in response directions. Mosses and understory species typical of coniferous forests were positively correlated with regeneration density. & Context Norway spruce Picea abies (L.) H. Karst. in Central Europe is at risk under climate change scenarios, particularly in mountain regions. Little is known about the impact of environmental factors on the natural regeneration of P. abies in lowelevation mountain forests. & Aims We aimed to assess impacts of distance from the riverbank, soil pH, and light availability on natural P. abies regeneration. We hypothesized that (1) natural P. abiesregeneration would depend on light availability and soil pH and (2) there are understory plant species which may indicate the microsites suitable for natural regeneration of P. abies. & Methods The study was conducted in the Stołowe Mountains National Park (SW Poland, 600–800 m a.s.l.). We established 160 study plots (25 m2 ) for natural regeneration, light availability, soil pH, and understory vegetation assessment

The Role of Binary Pulsars in Testing Gravity Theories

Radio pulsars are neutron stars (NSs) which emit collimated beams of radio waves, observed as pulses, once per rotation of the NS. A subgroup of the radio pulsars behave as highly stable clocks and monitoring the times of arrival of their radio pulses can provide an accurate determination of their positional, rotational, and orbital parameters, as well as indications on the properties of their space-time environment. In this chapter, we focus on the so-called relativistic binary pulsars, recycled NSs orbiting around a compact companion star. Some of them can be used as unique tools to test general relativity and other gravitational theories. The methodology for exploiting these sources as laboratories for gravity theories is first explained and then some of the most relevant recent results are reviewed. <P /