Ontogenic patterns of scent marking in red foxes, Vulpes vulpes (Carnivora: Canidae)

Scent marking is widely recognised to have a crucial function in many species. Most research has focussed on adults and very little is known about scent marking patterns during juvenile development. Using video records of juvenile red fox Vulpes vulpes across 6 years, we tested whether scent marking rates varied with age or sex, or whether juveniles remaining on the natal territory (philopatry) marked more frequently than those that disappeared. Our data show that male juvenile red foxes scent marked more than females during early development, but rates rapidly declined as they aged. In contrast, females showed a significantly later and slower rate of decline. Within females, individuals that remained in the natal area had higher scent marking rates than those that disappeared, suggesting that scent marking has a role in social group affiliation within litters. These results demonstrate that scent marking plays an important role in juveniles, including their intra-litter social interactions

Three-Dimensional Ray Tracing and Geophysical Inversion in Layered Media

In this paper the problem of finding seismic rays in a three-dimensional layered medium is examined. The "layers" are separated by arbitrary smooth interfaces that can vary in three dimensions. The endpoints of each ray and the sequence of interfaces it encounters are specified. The problem is formulated as a nonlinear system of equations and efficient, accurate methods of solution are discussed. An important application of ray tracing methods, which is discussed, is the nonlinear least squares estimation of medium parameters from observed travel times. In addition the "type" of each ray is also determined by the least squares process—this is in effect a deconvolution procedure similar to that desired in seismic exploration. It enables more of the measured data to be used without filtering out the multiple reflections that are not pure P-waves

Diffusion of hydrogen through metals in the presence of sodium

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Seasonal and sex-specific differences in feeding site attendance by red foxes Vulpes vulpes

Food provided by householders represents a key resource for urban red foxes Vulpes vulpes. Using long-term video footage, we examined how patterns of feeding site attendance varied with season, sex and likely residence status. For foxes attending frequently (>15%) we found feeding site attendance highest for females in spring, probably because of feeding dependent young, and lowest for both sexes in autumn because of changes in seasonal food abundance or in time spent in other activities. For infrequent attenders (<15%), females attended most often in autumn and winter, coinciding with the dispersal period. Male attendance was not higher during the breeding season. Our combined results show how feeding site attendance changes throughout the year relative to potential intrinsic and extrinsic factors

Tomographic reconstruction of velocity anomalies

An approximate inversion formula is proposed for the reconstruction of slowness anomalies in a known depth varying background field. The data are observed travel-time perturbations for reflections from a known planar reflector. The limitations of the formula are discussed and numerical examples are given

Highly-functionalised difluorinated cyclohexane polyols via the Diels–Alder reaction : regiochemical control via the phenylsulfonyl group

A difluorinated dienophile underwent cycloaddition reactions with a range of furans to afford cycloadducts whichcould be processed regio- and stereoselectively via episulfonium ions, generated by the reaction between their alkenyl groups and phenylsulfenyl chloride. The oxabicyclic products were oxidised to the phenylsulfonyl level and ring opened via E1CB or reductive desulfonative pathways to afford, ultimately, difluorinated cyclohexene or cyclohexane polyols

Requirements and Benefits of Implementing Just-In-Time Manufacturing for Small-Firm Manufacturers

This study explores the applicability of Just-In-Time (/IT ) manufacturing elements for small-firm manufacturers.  A survey of small-firm electronic firms  was undertaken  to identify  and  document  the level of /IT implementation alread y underway. Integrating concepts necessary for  successful  /IT  implemen­ tation along with the benefits of /IT are also discussed . It is suggested that /IT  manufacturing  is a viable and  useful strategy  to enhance the competitive  position  of small  manufacturing  firms

A Longitudinal Study of the Utilization of Production Management Techniques by Small Electronics Firms

This study is a longitudinal examination of the changes that have taken place in the utilization of production management tools and techniques through the 1981-1988 time period. Results suggest that small electronic manufacturing firms are actively attempting to improve the efficiency and effectiveness of their manufacturing  process. Of particular interest is the apparent emphasis on seeking  to contain costs while simplifying  the manufacturing process.