Differences in hip bone mineral density may explain the hip fracture pattern in osteoarthritic hips

Introduction In patients with osteoarthritis of the hip (OAH), trochanteric fractures are much more common than femoral neck fractures. One reason may be altered bone composition in the proximal femurs. OAH often leads to a fixed external rotation of the hip, leading to difficulties in positioning during DXA measurements. We compared BMD in OAH-affected legs and healthy legs

Progressive vertebral deformities despite unchanged bone mineral density in patients with sarcoidosis: a 4-year follow-up study

To evaluate the incidence of new and/or progressive vertebral deformities and changes in bone mineral density, we re-examined 66 patients with sarcoidosis after a follow-up period of four years. In 17 subjects (26%) new and/or progressive vertebral deformities were found, though BMD did not change significantly. INTRODUCTION: Previous studies from our group have shown that morphometric vertebral deformities suggestive of fractures can be found in 20% of patients with sarcoidosis, despite a normal bone mineral density (BMD). The aim of this study was to determine the incidence of new and/or progressive vertebral deformities and the evolution of BMD during the course of this disease. METHODS: BMD of the hip (DXA) and vertebral fracture assessment (VFA) with lateral single energy densitometry was performed at baseline and after 45 months in 66 patients with sarcoidosis. Potential predictors of new/ progressive vertebral deformities were assessed using logistic regression analysis. RESULTS: The BMD of the total group was unchanged after follow-up. The prevalence of vertebral deformities increased from 20 to 32% (p < 0.05); in 17 subjects (26%) new or progressive vertebral deformities were diagnosed. A lower T-score of the femoral neck [(OR = 2.5 (CI: 1.0-5.9), p < 0.05)] and mother with a hip fracture [(OR = 14.1 (CI: 1.4-142.6), p < 0.05)] were independent predictors of new/progressive deformities. CONCLUSIONS: In subjects with sarcoidosis the number of vertebral deformities increases in the course of this disease, despite unchanged BMD. The combination of low normal BMD and family history of fragility fractures confers an increased risk of the incidence of these deformities

A Controlled in-situ Fault Activation Experiment at Meter-scale Shows that High-pressure Fluid Injections Mostly Drive Aseismic Motion

International audienceUnderstanding how fluids pressure produce seismic or aseismic motion along faults is an important goal for seismic hazard assessment and for geological reservoir monitoring. Seismicity rate increase in fluid injection areas where some events may reach magnitude greater than 5. Besides, the microseismicity is one the few tools used to follow fluid migration at depth. In-situ experiments were performed in limestones similar to those observed in the Middle-East. By injecting fluids at high-pressure in the damaged zone of an inactive fault at 280m depth, we study the seismological and hydromechanical responses (recorded by 31 sensors) of different fracture types to a fluid perturbation. Only a few tests have generated seismicity even if ruptures are observed with a displacement sensor at the injection point. Detected earthquakes are characterized by high frequency content (0.6 to 3 KHz) and weak magnitude (-4). The relative and absolute locations (1.5m accuracy) indicate a lack of events in the vicinity of injection borehole. Results show that about 96% of the deformation is aseismic. Finally, our experiment showed that fluid injection mainly drives aseismic motion and the seismicity might be only an indirect effect related to stress transferred from the volume deformed by fluid pressurization

Aseismic Motions Drive a Sparse Seismicity During Fluid Injections Into a Fractured Zone in a Carbonate Reservoir

An increase in fluid pressure in faults can trigger seismicity and large aseismic motions. Understanding how fluid and faults interact is an essential goal for seismic hazard and reservoir monitoring, but this key relation remains unclear. We developed an in situ experiment of fluid injections at a 10&nbsp;meter scale. Water was injected at high pressure in different geological structures inside a fault damaged zone, in limestone at 280&nbsp;m depth in the Low Noise Underground Laboratory (France). Induced seismicity, as well as strains, pressure, and flow rate, was continuously monitored during the injections. Although nonreversible deformations related to fracture reactivations were observed for all injections, only a few tests generated seismicity. Events are characterized by a 0.5-to-4&nbsp;kHz content and a small magnitude (approximately −3.5). They are located within 1.5&nbsp;m accuracy between 1 and 12&nbsp;m from the injections. Comparing strain measurements and seismicity shows that more than 96% of the deformation is aseismic. The seismic moment is also small compared to the one expected from the injected volume. Moreover, a dual seismic behavior is observed as (1) the spatiotemporal distribution of some cluster of events is clearly independent from the fluid diffusion (2) while a diffusion-type pattern can be observed for some others clusters. The seismicity might therefore appear as an indirect effect to the fluid pressure, driven by aseismic motion and related stress perturbation transferred through failure

Internacionalización del capital y proceso productivo: análisis critico

Esta investigación trata de la manera de analizar la lógica de reproducción del capital, como relación social, enfocándola bajo el ángulo de su internacionalización. Se realiza un análisis crítico de los autores más importantes y de las implicaciones políticas de sus teorías. El objetivo es analizar estos enfoques teóricos para entenderlos y contribuir al estudio de la reproducción del capital.This research deals with the way of analysing the logic of capital reproduction, as a social relationship, focused on its internationalization. It presents a critical analysis of the most important authors and the political implications of their theories. The goal is to analyze these theoretical approaches to understand them and to contribute to the study of capital reproduction

Internationalization of capital and productive process: critical analysis

Esta investigación trata de la manera de analizar la lógica de reproducción del capital, como relación social, enfocándola bajo el ángulo de su internacionalización. Se realiza un análisis crítico de los autores más importantes y de las implicaciones políticas de sus teorías. El objetivo es analizar estos enfoques teóricos para entenderlos y contribuir al estudio de la reproducción del capital.This research deals with the way of analysing the logic of capital reproduction, as a social relationship, focused on its internationalization. It presents a critical analysis of the most important authors and the political implications of their theories. The goal is to analyze these theoretical approaches to understand them and to contribute to the study of capital reproduction