Capital Tax Competition and Returns to Scale

There is a gap between the predictions of capital tax competition models and the reality they purport to describe. In a standard capital-tax model, with head taxes, capital-importing regions tax capital and capital-exporting regions subsidize capital. In the real-world, competing regions appear to subsidize capital whether or not they are capital importers. We show that by relaxing the standard assumption of constant returns to scale symmetric regions in a Nash equilibrium may all subsidize capital.We also prove that any ine¢ciencies in a non-symmetric Nash equilibria arise entirely from regions’ incentives to manipulate the terms of trade, and not from increasing returns.We also compare our results to those in captial tax competition models without head taxes.

Capital tax competition with heterogeneous firms and agglomeration effects

Our paper extends the capital tax competition literature by incorporating heterogeneous capital and agglomeration. Our model nests the standard tax competition model as well as the special case in which there is agglomeration but no firm/capital heterogeneity and the opposite case, firm heterogeneity with no agglomeration. We build on the existing tax competition literature as well as establish a link between this literature and the more recent work on agglomeration using the new economic geography model. Our main contribution lies in allowing for firm heterogeneity which we show plays a role similar to decreasing returns in regional production

Cryptic complexity in felid vertebral evolution: shape differentiation and allometry of the axial skeleton

Members of the mammalian family Felidae (extant and extinct cats) are grossly phenotypically similar, but display a 300-fold range in body size, from less than 1 kg to more than 300 kg. In addition to differences in body mass, felid species show dietary and locomotory specializations that correlate to skull and limb osteological measurements, such as shape or cross-sectional area. However, ecological correlates to the axial skeleton are yet untested. Here, we build on previous studies of the biomechanical and morphological evolution of the felid appendicular skeleton by conducting a quantitative analysis of morphology and allometry in the presacral vertebral column across extant cats. Our results demonstrate that vertebral columns of arboreal, scansorial and terrestrial felids significantly differ in morphology, specifically in the lumbar region, while no distinction based on dietary specialization was found. Body size significantly influences vertebral morphology, with clear regionalization of allometry along the vertebral column, suggesting that anterior (cervicals and thoracics) and posterior (lumbar) vertebrae may be independently subjected to distinct selection pressures

Anatomically grounded estimation of hindlimb muscle sizes in Archosauria

In vertebrates, active movement is driven by muscle forces acting on bones, either directly or through tendinous insertions. There has been much debate over how muscle size and force are reflected by the muscular attachment areas (AAs). Here we investigate the relationship between the physiological cross-sectional area (PCSA), a proxy for the force production of the muscle, and the AA of hindlimb muscles in Nile crocodiles and five bird species. The limbs were held in a fixed position whilst blunt dissection was carried out to isolate the individual muscles. AAs were digitised using a point digitiser, before the muscle was removed from the bone. Muscles were then further dissected and fibre architecture was measured, and PCSA calculated. The raw measures, as well as the ratio of PCSA to AA, were studied and compared for intra-observer error as well as intra- and interspecies differences. We found large variations in the ratio between AAs and PCSA both within and across species, but muscle fascicle lengths are conserved within individual species, whether this was Nile crocodiles or tinamou. Whilst a discriminant analysis was able to separate crocodylian and avian muscle data, the ratios for AA to cross-sectional area for all species and most muscles can be represented by a single equation. The remaining muscles have specific equations to represent their scaling, but equations often have a relatively high success at predicting the ratio of muscle AA to PCSA. We then digitised the muscle AAs of Coelophysis bauri, a dinosaur, to estimate the PCSAs and therefore maximal isometric muscle forces. The results are somewhat consistent with other methods for estimating force production, and suggest that, at least for some archosaurian muscles, that it is possible to use muscle AA to estimate muscle sizes. This method is complementary to other methods such as digital volumetric modelling

Building, Dwelling, Dying: Architecture and History in Pakistan

There is a long history of scholars finding in architecture tools for thinking, whether this is the relationship between nature and culture in Simmel’s ruins, industrial capitalism in Benjamin’s Parisian arcades, or the rhythms of the primordial in Heidegger’s Black Forest farmhouse. But what does it mean to take seriously the concepts and dispositions articulated by architects themselves? How might processes of designing and making constitute particular forms of thinking? This article considers the words and buildings of Lahore-based architect Kamil Khan Mumtaz (b.1939) as an entry-point to such questions. It outlines how professional architecture in Pakistan has grappled with the unsettled status of the past in a country forged out of two partitions (1947 and 1971). Mumtaz’s work and thought – engaging questions of tradition, authority, craft and the sacred – demonstrates how these predicaments have been productive for conceptualising time, labour and the nature of dwelling in a postcolonial world

Musculoskeletal modelling of the Nile crocodile (Crocodylus niloticus) hindlimb: Effects of limb posture on leverage during terrestrial locomotion.

We developed a three-dimensional, computational biomechanical model of a juvenile Nile crocodile (Crocodylus niloticus) pelvis and hindlimb, composed of 47 pelvic limb muscles, to investigate muscle function. We tested whether crocodiles, which are known to use a variety of limb postures during movement, use limb orientations (joint angles) that optimise the moment arms (leverages) or moment-generating capacities of their muscles during different limb postures ranging from a high walk to a sprawling motion. We also describe the three-dimensional (3D) kinematics of the crocodylian hindlimb during terrestrial locomotion across an instrumented walkway and a treadmill captured via X-ray Reconstruction of Moving Morphology (biplanar fluoroscopy; 'XROMM'). We reconstructed the 3D positions and orientations of each of the hindlimb bones and used dissection data for muscle lines of action to reconstruct a focal, subject-specific 3D musculoskeletal model. Motion data for different styles of walking (a high, crouched, bended and two types of sprawling motion) were fed into the 3D model to identify whether any joints adopted near-optimal poses for leverage across each of the behaviours. We found that (1) the hip adductors and knee extensors had their largest leverages during sprawling postures and (2) more erect postures typically involved greater peak moment arms about the hip (flexion-extension), knee (flexion) and metatarsophalangeal (flexion) joints. The results did not fully support the hypothesis that optimal poses are present during different locomotory behaviours because the peak capacities were not always reached around mid-stance phase. Furthermore, we obtained few clear trends for isometric moment-generating capacities. Therefore, perhaps peak muscular leverage in Nile crocodiles is instead reached either in early/late stance or possibly during swing phase or other locomotory behaviours that were not studied here, such as non-terrestrial movement. Alternatively, our findings could reflect a trade-off between having to execute different postures, meaning that hindlimb muscle leverage is not optimised for any singular posture or behaviour. Our model, however, provides a comprehensive set of 3D estimates of muscle actions in extant crocodiles which can form a basis for investigating muscle function in extinct archosaurs

A proposed standard for quantifying 3-D hindlimb joint poses in living and extinct archosaurs

The last common ancestor of birds and crocodylians plus all of its descendants (clade Archosauria) dominated terrestrial Mesozoic ecosystems, giving rise to disparate body plans, sizes, and modes of locomotion. As in the fields of vertebrate morphology and paleontology more generally, studies of archosaur skeletal structure have come to depend on tools for acquiring, measuring, and exploring three-dimensional (3-D) digital models. Such models, in turn, form the basis for many analyses of musculoskeletal function. A set of shared conventions for describing 3-D pose (joint or limb configuration) and 3-D kinematics (change in pose through time) is essential for fostering comparison of posture/movement among such varied species, as well as for maximizing communication among scientists. Following researchers in human biomechanics, we propose a standard methodological approach for measuring the relative position and orientation of the major segments of the archosaur pelvis and hindlimb in 3-D. We describe the construction of anatomical and joint coordinate systems using the extant guineafowl and alligator as examples. Our new standards are then applied to three extinct taxa sampled from the wider range of morphological, postural, and kinematic variation that has arisen across >250 million years of archosaur evolution. These proposed conventions, and the founding principles upon which they are based, can also serve as starting points for measuring poses between elements within a hindlimb segment, for establishing coordinate systems in the forelimb and axial skeleton, or for applying our archosaurian system more broadly to different vertebrate clades

Materialising architecture for social care: brick walls and compromises in design for later life.

This article reports on an ethnography of architectural projects for later life social care in the UK. Informed by recent debates in material studies and ‘materialities of care’ we offer an analysis of a care home project that is sensitive to architectural materials that are not normally associated with care and wellbeing. Although the care home design project we focus on in this article was never built, we found that design discussions relating to both a curved brick wall and bricks more generally were significant to its architectural ‘making’. The curved wall and the bricks were used by the architects to encode quality and values of care into their design. This was explicit in the design narrative that was core to a successful tender submitted by a consortium comprising architects, developers, contractors, and a care provider to a local authority who commissioned the care home. However, as the project developed, initial consensus for the design features fractured. Using a materialised analysis, we document the tussles generated by the curved wall and the bricks and argue that mundane building materials can be important to, and yet marginalised within, the relations inherent within an ‘architectural care assemblage.’ During the design process we saw how decisions about materials are contentious and they act as a catalyst of negotiations that compromise ‘materialities of care.