Palaeopathology and horse domestication: the case of some Iron Age horses horn the Altai Mountains, Siberia

We discuss the use of palaeopathological indicators in horse skeletons as potential sources I of evidence about the use of horses for riding and traction. We suggest that this type of information can provide an important and perhaps more reliable complement to other indicators of domestication such as morphological changes, kill-off patterns and bit wear, which suffer from various ambiguities of interpretation. We emphasise the importance of studying the skeletons of modern control samples of horses of known life histories as a constraint on the interpretation of palaeopathological evidence and demonstrate the viability of the technique through a comparison of free-living Exmoor ponies with Iron Age Scythian horse remains from Siberia. We demonstrate that stresses caused by riding produce characteristic lesions on the vertebrae which can be distinguished from age-related damage in free-living animals, and in addition that these stresses could have been moderated by changes of saddle design in the Medieval period. These results also throw new light on customs associated with horse burial

Monetary disinflation with inflation inertia: Central bank autonomy in an open economy

This paper draws on the strategic policy literature to model the optimal disinflation trajectory for an economy subject to external shocks and where the inflation process is characterised by a degree of expectational and externally-sourced inertia. In particular, it shows that the optimal inflation rate will converge on an interval bounded by the targetted rate and by the rate of externally-sourced inflation. Moreover, the point of convergence will vary with the openness of the economy, with the degree of wage flexibility, and with the relative weight given to the inflation objective. The policy implications of these results are examined with some reference to the New Zealand institutional environment and the disinflation of the post-1984 period. New Zealand did not adopt a disinflationary policy stance until late 1984, at a time when most other OECD countries were already well down their disinflation paths. As if to compensate for the late start, and in anticipation of the ratifying legislation, the Reserve Bank of New Zealand narrowed its macro-policy focus to a single objective - inflation. The Reserve Bank of New Zealand Act 1989 subsequently set "stability in the general level of prices" (currently defined in terms of maintaining an absolute target for consumer price inflation of O to 2 percent) as the primary macro-objective for monetary policy and freed the Bank from day-to-day political directives on the implementation of policy. The legislation has generated a vigorous Antipodean debate about optimal monetary policy in a small, open economy. This paper provides a theoretical underpinning for the contention that, in general, monetary disinflation under the Reserve Bank Act is a sub-optimal strategy

A Kinematic Analysis of Visual and Haptic Contributions to Precision Grasping in a Patient With Visual Form Agnosia and in Normally-Sighted Populations

Skilled arm and hand movments designed to obtain and manipulate objects (prehension) is one of the defining features of primates. According to the two visual system hypothesis (TVSH) vision can be parsed into two systems: (1) the ventral ‘stream’ of the occipital and inferotemporal cortex which services visual perception and other cognitive functions and (2) the ‘dorsal stream’ of the occipital and posterior parietal cortex which services skilled, goal-directed actions such as prehension. A cornerstone of the TVSH is the ‘perception-action’ dissociation observed in patient DF who suffers from visual form agnosia following bilateral damage to her ventral stream. DF cannot discriminate amongst objects on the basis of their visual form. Remarkably, however, her hand preshapes in-flight to suit the sizes of the goal objects she fails to discriminate amongst when she reaches out to pick them up; That is, unless she is denied the opportunity to touch the object at the end of her reach. This latter finding has led some to question the TVSH, advancing an alternative account that is centered on visuo-haptic calibration. The current work examines this alternative view. First, the validity of the measurements that have underlined this line of investigation is tested, rejecting some measures while affirming others. Next, the visuo-haptic calibration account is tested and ultimately rejected on the basis of four key pieces of evidence: Haptics and vision need not correlate to show DF’s ‘perception-action’ dissociation; Haptic input does not potentiate DF’s deficit in visual form perception; DF’s grasp kinematics are normal as long as she is provided a target proxy; and denying tactile feedback induces a shift in grasp kinematics away from natural grasps and towards pantomimed (simulated) ones in normally-sighted populations

PRESERVED GRIP SCALING TO UNSEEN OBJECTS FOLLOWING A UNILATERAL LESION TO V1 FOR IMMEDIATE BUT NOT DELAYED GRASPING

Patients with damage to V1 can sometimes direct actions towards ‘unseen’ targets located in areas of the visual field that are deemed ‘blind’ on the basis of static perimetry tests. Here, we show that a patient with a complete right homonymous hemianopia after a V1 lesion remains sensitive to the width of objects presented in her blind field but only when reaching out to grasp them in ‘real-time’. A subsequent fMRI experiment indicated that these preserved abilities are likely mediated by spared extra-geniculostriate pathways, while a small “tag” of occipital cortex located at the occipital pole remained unresponsive. Taken together, the results support the view that visually guided movements can be mediated by pathways that do not support visual consciousness

Achieving hip fracture surgery within 36 hours: an investigation of risk factors to surgical delay and recommendations for practice

BACKGROUND: The UK hip fracture best practice tariff (BPT) aims to deliver hip fracture surgery within 36 h of admission. Ensuring that delays are reserved for conditions which compromise survival, but are responsive to medical optimisation, would help to achieve this target. We aimed to identify medical risk factors of surgical delay, and assess their impact on mortality. MATERIALS AND METHODS: Prospectively collected patient data was obtained from the National Hip Fracture Database (NHFD). Medical determinants of surgical delay were identified and analysed using a multivariate regression analysis. The mortality risk associated with each factor contributing to surgical delay was then calculated. RESULTS: A total 1361 patients underwent hip fracture surgery, of which 537 patients (39.5 %) received surgery within 36 h of admission. Following multivariate analyses, only hyponatraemia was deduced to be a significant risk factor for delay RR = 1.24 (95 % CI 1.06-1.44). However, following a validated propensity score matching process, a Pearson chi-square test failed to demonstrate a statistical difference in mortality incidence between the hypo- and normonatraemic patients [χ (2) (1, N = 512) = 0.10, p = 0.757]. CONCLUSIONS: Hip fracture surgery should not be delayed in the presence of non-severe and isolated hyponatraemia. Instead, surgical delay may only be warranted in the presence of medical conditions which contribute to mortality and are optimisable. LEVEL OF EVIDENCE: III

Parenclitic and Synolytic Networks Revisited

© 2021 Nazarenko, Whitwell, Blyuss and Zaikin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). https://creativecommons.org/licenses/by/4.0/Parenclitic networks provide a powerful and relatively new way to coerce multidimensional data into a graph form, enabling the application of graph theory to evaluate features. Different algorithms have been published for constructing parenclitic networks, leading to the question—which algorithm should be chosen? Initially, it was suggested to calculate the weight of an edge between two nodes of the network as a deviation from a linear regression, calculated for a dependence of one of these features on the other. This method works well, but not when features do not have a linear relationship. To overcome this, it was suggested to calculate edge weights as the distance from the area of most probable values by using a kernel density estimation. In these two approaches only one class (typically controls or healthy population) is used to construct a model. To take account of a second class, we have introduced synolytic networks, using a boundary between two classes on the feature-feature plane to estimate the weight of the edge between these features. Common to all these approaches is that topological indices can be used to evaluate the structure represented by the graphs. To compare these network approaches alongside more traditional machine-learning algorithms, we performed a substantial analysis using both synthetic data with a priori known structure and publicly available datasets used for the benchmarking of ML-algorithms. Such a comparison has shown that the main advantage of parenclitic and synolytic networks is their resistance to over-fitting (occurring when the number of features is greater than the number of subjects) compared to other ML approaches. Secondly, the capability to visualise data in a structured form, even when this structure is not a priori available allows for visual inspection and the application of well-established graph theory to their interpretation/application, eliminating the “black-box” nature of other ML approaches.Peer reviewedFinal Published versio