Effects of Natura 2000 on nontarget bird and butterfly species based on citizen science data.

The European Union's Natura 2000 (N2000) is among the largest international networks of protected areas. One of its aims is to secure the status of a predetermined set of (targeted) bird and butterfly species. However, nontarget species may also benefit from N2000. We evaluated how the terrestrial component of this network affects the abundance of nontargeted, more common bird and butterfly species based on data from long-term volunteer-based monitoring programs in 9602 sites for birds and 2001 sites for butterflies. In almost half of the 155 bird species assessed, and particularly among woodland specialists, abundance increased (slope estimates ranged from 0.101 [SD 0.042] to 3.51 [SD 1.30]) as the proportion of landscape covered by N2000 sites increased. This positive relationship existed for 27 of the 104 butterfly species (estimates ranged from 0.382 [SD 0.163] to 4.28 [SD 0.768]), although most butterflies were generalists. For most species, when land-cover covariates were accounted for these positive relationships were not evident, meaning land cover may be a determinant of positive effects of the N2000 network. The increase in abundance as N2000 coverage increased correlated with the specialization index for birds, but not for butterflies. Although the N2000 network supports high abundance of a large spectrum of species, the low number of specialist butterflies with a positive association with the N2000 network shows the need to improve the habitat quality of N2000 sites that could harbor open-land butterfly specialists. For a better understanding of the processes involved, we advocate for standardized collection of data at N2000 sites.

Efectos de Natura 2000 sobre las Especies No Focales de Aves y Mariposas con Base en Datos de Ciencia Ciudadana Resumen La red Natura 2000 (N2000) de la Unión Europea está entre las redes internacionales más grandes de áreas protegidas. Uno de sus objetivos es asegurar el estado de un conjunto predeterminado de especies de aves y mariposas (focales). Sin embargo, las especies no focales también pueden beneficiarse con la N2000. Evaluamos cómo el componente terrestre de esta red afecta la abundancia de las especies de aves y mariposas no focales más comunes con base en los datos de programas de monitoreo voluntario a largo plazo en 9,602 sitios para aves y en 2,001 sitios para mariposas. En casi la mitad de las 155 especies de aves evaluadas, particularmente entre aquellas especies especialistas en zonas boscosas, la abundancia incrementó (los estimaciones de la pendiente variaron desde 0.101 [DS 0.042] hasta 3.51 [DS 1.30]) conforme incrementó la proporción del paisaje cubierto por sitios de la N2000. Esta relación positiva existió en 27 de las 104 especies de mariposas (con una variación de estimaciones desde 0.382 [DS 0.163] hasta 4.28 [DS 0.768]), aunque la mayoría de las especies de mariposas fueron generalistas. Cuando se consideraron las covarianzas de cobertura de suelo estas relaciones positivas no fueron evidentes para la mayoría de las especies, lo que significa que la cobertura de suelo puede ser una determinante de los efectos positivos de la red N2000. El incremento en la abundancia conforme aumentó la cobertura de la N2000 estuvo correlacionado con el índice de especialización de las aves, pero no el de las mariposas. Aunque la red N2000 sostiene la abundancia alta de un espectro amplio de especies, el bajo número de mariposas especialistas con una asociación positiva a la red N2000 demuestra la necesidad de mejorar la calidad del hábitat de los sitios N2000 que podrían albergar a mariposas especialistas de campo abierto. Para un mejor entendimiento de los procesos involucrados, promovemos una recolección estandarizada de datos en los sitios de la red N2000.

Incorporating a statistically based shape model into a system for computer-assisted anterior cruciate ligament surgery.

This paper addresses the problem of extrapolating very sparse three-dimensional (3-D) data to obtain a complete surface representation. A new method that uses statistical shape models is proposed and its application to computer-assisted anterior cruciate ligament (ACL) reconstruction is detailed. The rupture of the ACL has become one of the most common knee injuries. One problem during reconstruction is to find the optimal attachment points for the graft. Therefore a system for computer-assisted reconstruction of the ACL has been proposed by TIMC laboratory. During surgery the surgeon collects several data points on the tibial and femoral joint surface with a 3-D localizer system. These 3-D data are used to find those attachment points resulting in a low anisometry of the graft, while preventing impingement between the graft and the femoral notch. As the collected data points only cover a small surface patch of the femur, it is desirable to extrapolate these data to also have a visualization in those areas where no data points are available. A sufficiently good approximation of the actual femur by the model would further allow us to better deal with the notch impingement problem of the graft. The chosen approach is to fit a deformable model to the data points, it can be subdivided into two steps, constructing the model and fitting this model to the data. To incorporate a priori knowledge into the model, the allowed deformations are determined by the statistics of the shape variation of a set of training objects. Matching the training objects together is obtained by elastic registration of surface points using octree splines. The fitting process of the sparse intra-operative data with the statistical model results in a non-linear multi-dimensional function minimization. A hybrid search strategy combining local and global methods is used to avoid local minima. First experimental results with a model generated from 10 femurs are presented, including fitting of the model with both simulated and real intra-operative data.

[Major dysplasia of the trochlea. Contribution to the measurement of A.T. T.G. Proposal of a x-ray computed tomographic protocol]. / Dysplasie trochléenne majeure. Contribution à la mesure de la T.A. G.T. Proposition d'un protocole scanographique.

The A.T. T.G.'s scanographic measure sets problems in the major dysplasic trochlear groove because point G.T. is quite impossible to determine. We purpose to define it by an original procedure based on bidimensional reconstruction of A.T. T.G. system. Point G.T. is defined by extrapolation: it is situated at the junction of proximal trochlear scan section with the line representing distal trochlear groove.

[The tibial slope. Proposal for a measurement method]. / La pente tibiale. Proposition pour une méthode de mesure.

The posterior inclination of the tibial plateaus relative to the longitudinal axis of the bone, also called tibial slope, is important to know for the pathology of the cruciate ligaments and to lay some knee prostheses. We have chosen a reproducible method to measure it, on the basis of a large radiograph of the lower limb. A radio-anatomical analysis of the morphology of the tibia has first been carried out to properly choose axes that are easy to find and useful in practice. The accuracy of the measurement is to within one degree. In adults, the slope ranges from 0 to 18 degrees, according to the subjects, with variations form one knee to the other.

[A simple technique of removal of femoral cement plug in total hip prosthesis revision]. / Une technique simple d'ablation du bouchon de ciment fémoral au cours des révisions des prothèses de hanche.

During replacement of loosened or painful cemented femoral prosthetic stem, the extraction of a large size distal cement plug is rarely an easy matter. To make it simple, quick and safe (no wide surgical exposure, no X-ray exposure) we propose a new technique based upon the perforation of the cement plug by a drill which crosses a jig inserted into the cavity where the femoral stem had been removed. Correctly used the procedure can help the surgeon to solve the difficult problem of removing the femoral cement plug and consequently it can allow the placement of a biomechanically ideal conventional length femoral component into a femur not weakened by a perforation, a fenestration or an osteotomy.

[The median functional slope of the tibia. Principle. Technique of measurement. Value. Interest]. / La pente tibiale fonctionnelle médiane. Principe. Technique de mesure. Valeur. Intérêt.

The tibial slope is an important datum in knee surgery; the levelling by a uni- or bicompartmental prosthesis preserving both cruciate ligaments requires to maintain this slope. The postoperative rehabilitation of the A.C.L. plasties, especially those performed with a patellar tendon and the surgical cure of a genu recurvatum, must integrate this notion. Even if the anatomical slopes are usable in prosthetic surgery, they do not seem precise enough in the field of A.C.L. and tibia recurvatum surgery. In these indications, the authors propose to determine the functional tibial slope defined as being the complement of the angle formed by the tangent to the tibial medial plateau and the lateral mechanical axis of the leg. Measured to an average of 7 degrees on 238 knees, the average median functional slope cannot be deduced from anatomical slopes; it must be measured on a lateral teleradiographic view of the lower limb, the knee being in full extension and X-rayed in true posterior and inferior lateral view.

[X-ray diagnosis of the patellar instability. Incidences in external rotation]. / Diagnostic radiographique de l'instabilité rotulienne.

The classical X-Ray exploration of the patellar instability is done through incidences performed with knees in a 30 degrees flexion and a 0 degrees rotation. To this basic investigation the authors propose to add original, more physiological incidences performed with knees in external rotation. Because of their extreme sensitiveness, these incidences with a 30 degrees external rotation allow a more accurate diagnosis of the patellar instability (and thereby a better breaking up of the still too nebulous chapter of patellar chrondropathies) and a more critical checking of the surgical centering of the patella. Technically easy to perform they should enter into the usual practice of X-Ray exploration of any mechanical knee.

Analysis of anatomic positioning in computer-assisted and conventional anterior cruciate ligament reconstruction.

INTRODUCTION: Anterior cruciate ligament (ACL) reconstruction should be anatomic while achieving favorable anisometric behavior to avoid impingement with the femoral notch. Computerization enables these biomechanical conditions to be optimally fulfilled; but what of anatomic positioning? The present study compared the positioning of tibial and femoral tunnels, drilled using either a conventional ACL guide or a navigation system, using the anatomic foot-print areas of the native ACL. MATERIAL AND METHODS: This cadaver study used computerized recording to compare tibial and femoral ACL attachment areas to the positioning of tunnels created either conventionally or under computer-guided navigation. RESULTS: Computer guidance enabled the tibial and femoral tunnels to be systematically positioned within the anatomic area and, as regards the tibial area, within the anterior third near to the medial tibial spine, without femoral notch impingement. Anisometry was in all cases favorable, at a mean 3.3 ± 0.7 mm; using a conventional guide, anisometry was favorable in only 50% of cases, at a mean 5.4 ± 1.2 mm. CONCLUSION: Computer-guided navigation ensured implant positioning within the so-called anatomometric area of the native ACL attachment, avoiding impingement with the femoral notch. LEVEL OF EVIDENCE: Level 2.

Evolution of habitat-dependent sex allocation in plants: superficially similar to, but intrinsically different from animals.

Because pollen disperses and ovules do not, a basic difference in dispersal abilities of male and female gametes exists in plants. With an analytical model, we show that the combination of such sex-biased dispersal of gametes and variation of habitat quality results in two opposite selective forces acting on the evolution of sex allocation in plants: (i) a plant should overproduce pollen in good patches and overproduce ovules in poor patches in order to equilibrate secondary sex ratios of gametes after pollen dispersal; (ii) a plant should overproduce ovules in good patches and overproduce pollen in poor patches in order to increase the likelihood that its progeny establishes in good patches. Our theoretical results indicate that the evolution of habitat-dependent sex allocation should be favoured in plants, in a direction that depends on the relative dispersal ability of pollen and seeds. We also show that superficially similar predictions obtained for habitat-dependent evolutionarily stable sex allocation in animals actually result from a completely different balance between the two underlying evolutionary forces.

Mathematical determination of the tibial insertion of the patellar tendon using computed tomography images.

Misalignment of the extensor apparatus is an essential factor in impairment of the patellar-femoral joint. This may be partly or entirely responsible for patellar dislocation or lateral patellar-femoral arthrosis. One surgical method to correct the pathology is medial transposition of the patellar ligament on the tibial tuberosity (anteriorly or posteriorly, distally or ventrally). These interventions correct misalignment of the extensor apparatus relative to statistical norms. We propose a mathematical method based on the use of computed tomography (CT) images to determine the ideal tibial insertion for the patellar tendon. This method is based on biomechanical modeling and the use of equipressure criteria. It is the first step in allowing the use of mathematics to model correctly tibial insertion of the patellar ligament, an entirely new development. This is important because it will allow surgeons greater accuracy in distal correction of extensor apparatus misalignments.

Computer-assisted knee anterior cruciate ligament reconstruction: first clinical tests.

Anterior cruciate ligament reconstruction is a delicate task. The procedure of choice is the patellar tendon bone autograft, but an anisometric position of this tendon often leads to failure. We allows positioning of the central part of the ligament graft at the least anisometric sites. The system uses a workstation and a three-dimensional optical localizer to create images that represent knee kinematics. The surgeon uses these images to guide the surgery. This technique has been validated on eight cadavers and 12 patients.