The effects of anxiety and expertise on visual search strategy in karate were examined. Expert and novice karate performers moved in response to taped karate offensive sequences presented under low (LA) and high anxiety (HA). Expert performers exhibited superior anticipation under LA and HA. No differences were observed between groups in number of fixations, mean fixation duration, or total number of fixation locations per trial. Participants displayed scan paths ascending and descending the centerline of the body, with primary fixations on head and chest regions. Participants demonstrated better performance under HA than under LA. Anxiety had a significant effect on search strategy, highlighted by changes in mean fixation duration and an increase in number of fixations and total number of fixation locations per trial. Increased search activity was more pronounced in novices, with fixations moving from central to peripheral body locations. These changes in search strategy with anxiety might be caused by peripheral narrowing or increased susceptibility to peripheral distractors.

SummaryCannula cricothyroidotomy is recommended for emergency transtracheal ventilation by all current airway guidelines. Success with this technique depends on the accurate and rapid identification of percutaneous anatomical landmarks. Six healthy subjects underwent neck ultrasound to delineate the borders of the cricothyroid membrane. The midline and bisecting transverse planes through the membrane were marked with an invisible ink pen which could be revealed with an ultraviolet light. Eighteen anaesthetists were then invited to mark an entry point for cricothyroid membrane puncture. Only 32 (30%) attempts by anaesthetists accurately marked the skin area over the cricothyroid membrane. Of these only 11 (10%) marked over the centre point of the membrane. Entry point accuracy was not significantly affected by subjects' weight, height, body mass index, neck circumference or cricothyroid dimensions. Consultant and registrar anaesthetists were significantly more accurate than senior house officers at correctly identifying the cricothyroid membrane. Accuracy of percutaneously identifying the cricothyroid membrane was poor. Ultrasound may assist in identifying anatomical landmarks for cricothyroidotomy.

This article presents a unified clinical theory that links established facts about the physiology of bone and homeostasis, with those involved in the healing of fractures and the development of nonunion. The key to this theory is the concept that the tissue that forms in and around a fracture should be considered a specific functional entity. This 'bone-healing unit' produces a physiological response to its biological and mechanical environment, which leads to the normal healing of bone. This tissue responds to mechanical forces and functions according to Wolff's law, Perren's strain theory and Frost's concept of the "mechanostat". In response to the local mechanical environment, the bone-healing unit normally changes with time, producing different tissues that can tolerate various levels of strain. The normal result is the formation of bone that bridges the fracture - healing by callus. Nonunion occurs when the bone-healing unit fails either due to mechanical or biological problems or a combination of both. In clinical practice, the majority of nonunions are due to mechanical problems with instability, resulting in too much strain at the fracture site. In most nonunions, there is an intact bone-healing unit. We suggest that this maintains its biological potential to heal, but fails to function due to the mechanical conditions. The theory predicts the healing pattern of multifragmentary fractures and the observed morphological characteristics of different nonunions. It suggests that the majority of nonunions will heal if the correct mechanical environment is produced by surgery, without the need for biological adjuncts such as autologous bone graft. Cite this article: Bone Joint J 2016;98-B:884-91.

We compared the outcome of patients treated for an intertrochanteric fracture of the femoral neck with a locked, long intramedullary nail with those treated with a dynamic hip screw (DHS) in a prospective randomised study. Each patient who presented with an extra-capsular hip fracture was randomised to operative stabilisation with either a long intramedullary Holland nail or a DHS. We treated 92 patients with a Holland nail and 98 with a DHS. Pre-operative variables included the Mini Mental test score, patient mobility, fracture pattern and American Society of Anesthesiologists grading. Peri-operative variables were anaesthetic time, operating time, radiation time and blood loss. Post-operative variables were time to mobilising with a frame, wound infection, time to discharge, time to fracture union, and mortality. We found no significant difference in the pre-operative variables. The mean anaesthetic and operation times were shorter in the DHS group than in the Holland nail group (29.7 vs 40.4 minutes, p < 0.001; and 40.3 vs 54 minutes, p < 0.001, respectively). There was an increased mean blood loss within the DHS group versus the Holland nail group (160 ml vs 78 ml, respectively, p < 0.001). The mean time to mobilisation with a frame was shorter in the Holland nail group (DHS 4.3 days, Holland nail 3.6 days, p = 0.012). More patients needed a post-operative blood transfusion in the DHS group (23 vs seven, p = 0.003) and the mean radiation time was shorter in this group (DHS 0.9 minutes vs Holland nail 1.56 minutes, p < 0.001). The screw of the DHS cut out in two patients, one of whom underwent revision to a Holland nail. There were no revisions in the Holland nail group. All fractures in both groups were united when followed up after one year. We conclude that the DHS can be implanted more quickly and with less exposure to radiation than the Holland nail. However, the resultant blood loss and need for transfusion is greater. The Holland nail allows patients to mobilise faster and to a greater extent. We have therefore adopted the Holland nail as our preferred method of treating intertrochanteric fractures of the hip.

SUMMARYAn implementation of the boundary element method requires the accurate evaluation of many integrals. When the source point is far from the boundary element under consideration, a straightforward application of Gaussian quadrature suffices to evaluate such integrals. When the source point is on the element, the integrand becomes singular and accurate evaluation can be obtained using the same Gaussian points transformed under a polynomial transformation which has zero Jacobian at the singular point.A class of integrals which lies between these two extremes is that of 'nearly singular' integrals. Here, the source point is close to, but not on, the element and the integrand remains finite at all points. However, instead of remaining flat, the integrand develops a sharp peak as the source point moves closer to the element, thus rendering accurate evaluation of the integral difficult. This paper presents a transformation, based on the sinh function, which automatically takes into account the position of the projection of the source point onto the element, which we call the 'nearly singular point', and the distance from the source point to the element. The transformation again clusters the points towards the nearly singular point, but does not have a zero Jacobian. Implementation of the transformation is straightforward and could easily be included in existing boundary element method software.It is shown that, for the two-dimensional boundary element method, several orders of magnitude improvement in relative error can be obtained using this transformation compared to a conventional implementation of Gaussian quadrature. Asymptotic estimates for the truncation errors are also quoted.

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It is well known that the finite HILBERT transform T is a NOETHER (FREDHOLM) operator when considered as a map from Y p into itself if 1 < p < 2 or 2 < p c co. When p = 2, the map T is not a NOETHER operator. We present two theorems which characterize the range of T in Y 2 and, as immediate consequences, give simple expressions for its inverse. IntroductionWe consider the finite HILBERT transform T over the open arc 1-1, l[. A well known result of M. RIESZ [12] tells us that the restriction Tp of T to the BANACH space Y p := YPa-1, 10 defines a continuous linear operator from Y p into Y p for every p €11, a[. Unless p = 2, the map T, is a NOETHER operator (for the definition of NOETHER operators, see section 2). The purpose of this paper is to investigate the operator T, : Y z + Y 2 whose range is a proper dense subspace of Y 2 . This we do in sections 3 and 4, after summarizing some basic results in section 2.Our principal result which characterizes the range of T, is given in Theorem 3.2. This is then followed by a simple inversion formula for T2 which is valid for all functions in the range of T2. These results are derived essentially by considering those operators T,, 1 < p < 2, whose restrictions to Y p are 7''.In section4, on the other hand, the properties of the operators T, , 2 < p c 00, are applied to the study of T2. In Theorem 4.2, the subspace of the range of T2, which consists of all functions f such that (1 -x2)-lI2 f is LEBESGUE integrable, is characterized and the restriction of T;' to that subspace is shown to have the same form as T i ' , 2 c p < m.From Theorem 4.2, the question naturally arises as to whether or not there exist functions 4 E Y 2 for which (1 -x2)-'"

SUMMARYA new transformation technique is introduced for evaluating the two-dimensional nearly singular integrals, which arise in the solution of Laplace's equation in three dimensions, using the boundary element method, when the source point is very close to the element of integration. The integrals are evaluated using (in a product fashion) a transformation which has recently been used to evaluate one-dimensional near singular integrals. This sinh transformation method automatically takes into account the position of the projection of the source point onto the element and also the distance b between the source point and the element. The method is straightforward to implement and, when it is compared with a number of existing techniques for evaluating two-dimensional near singular integrals, it is found that the sinh method is superior to the existing methods considered, both for potential integrals across the full range of b values considered (00.01. For smaller values of b, the use of the L −1/5 1 method is recommended for flux integrals.