El papel de la OTAN y su evolución en la era de la globalización

Discurso del secretario general de la OTAN pronunciado en Madrid el 10 de septiembre de 2010, en un acto organizado por el Real Instituto Elcano

ret2spec: Speculative Execution Using Return Stack Buffers

Speculative execution is an optimization technique that has been part of CPUs for over a decade. It predicts the outcome and target of branch instructions to avoid stalling the execution pipeline. However, until recently, the security implications of speculative code execution have not been studied. In this paper, we investigate a special type of branch predictor that is responsible for predicting return addresses. To the best of our knowledge, we are the first to study return address predictors and their consequences for the security of modern software. In our work, we show how return stack buffers (RSBs), the core unit of return address predictors, can be used to trigger misspeculations. Based on this knowledge, we propose two new attack variants using RSBs that give attackers similar capabilities as the documented Spectre attacks. We show how local attackers can gain arbitrary speculative code execution across processes, e.g., to leak passwords another user enters on a shared system. Our evaluation showed that the recent Spectre countermeasures deployed in operating systems can also cover such RSB-based cross-process attacks. Yet we then demonstrate that attackers can trigger misspeculation in JIT environments in order to leak arbitrary memory content of browser processes. Reading outside the sandboxed memory region with JIT-compiled code is still possible with 80\% accuracy on average.Comment: Updating to the cam-ready version and adding reference to the original pape

Efficiency of Lift Production in Flapping and Gliding Flight of Swifts

Many flying animals use both flapping and gliding flight as part of their routine behaviour. These two kinematic patterns impose conflicting requirements on wing design for aerodynamic efficiency and, in the absence of extreme morphing, wings cannot be optimised for both flight modes. In gliding flight, the wing experiences uniform incident flow and the optimal shape is a high aspect ratio wing with an elliptical planform. In flapping flight, on the other hand, the wing tip travels faster than the root, creating a spanwise velocity gradient. To compensate, the optimal wing shape should taper towards the tip (reducing the local chord) and/or twist from root to tip (reducing local angle of attack). We hypothesised that, if a bird is limited in its ability to morph its wings and adapt its wing shape to suit both flight modes, then a preference towards flapping flight optimization will be expected since this is the most energetically demanding flight mode. We tested this by studying a well-known flap-gliding species, the common swift, by measuring the wakes generated by two birds, one in gliding and one in flapping flight in a wind tunnel. We calculated span efficiency, the efficiency of lift production, and found that the flapping swift had consistently higher span efficiency than the gliding swift. This supports our hypothesis and suggests that even though swifts have been shown previously to increase their lift-to-drag ratio substantially when gliding, the wing morphology is tuned to be more aerodynamically efficient in generating lift during flapping. Since body drag can be assumed to be similar for both flapping and gliding, it follows that the higher total drag in flapping flight compared with gliding flight is primarily a consequence of an increase in wing profile drag due to the flapping motion, exceeding the reduction in induced drag

Variations in pathways and resource use in follow-up after abnormal mammography screening:a nationwide register-based study

Purpose: Mammography screening reduces breast cancer mortality, but a successful screening programme depends on both high participation and a sufficient follow-up of abnormalities. This study investigated patterns of follow-up after abnormal screening mammography in Denmark, and whether the variation was associated with health care resource use. Methods: We included 19,458 women aged 50–69 years with an abnormal screening mammography during a 3-year period of 2014–2016. Women were followed until the end of 2018. Their follow-up pathway was categorized in terms of the timeliness, appropriateness (i.e. whether all recommended diagnostic tests were utilized), and the ratio of benign vs. malignant surgeries. Further, we estimated health care resource use including post-diagnostic imaging and surgery procedures. Results: Ninety-seven percent of women had a diagnostic follow-up test within 6 months and 94% of those had diagnostic procedures in accordance with the recommendations. The proportion with timely follow-up (i.e. within 1 month) was 83%, but varied significantly between administrative regions (p &lt; 0.001), and also between women with a screen-detected cancer and those with a false-positive mammogram (87% vs. 81%, p &lt; 0.001). The ratio between having a benign versus a malignant surgery was 1:8, but it varied depending on which tests were used for diagnosis. The average number of procedures was, generally, in accordance with the recommendations. Conclusion: In most cases, follow-up after abnormal screening mammography followed national recommendations. We nevertheless found that this was not always the case in certain subgroups and administrative regions.</p

Clinical procedures used to diagnose inflammatory bowel disease:real-world evidence from a Danish nationwide population-based study

OBJECTIVE: Although clinical guidelines exist, the diagnostic work-up for diagnosing inflammatory bowel disease (IBD) is complex and varies in clinical practice. This study used real-life data to characterise the current diagnostic procedures used to establish IBD diagnoses in a Danish nationwide setting. DESIGN: Person-level data on patients diagnosed with IBD between 1 January 2014 and 30 June 2018 were linked between Danish health registers. Information on age, sex, registration of other gastrointestinal diseases, and diagnostic procedures (endoscopies, biopsies, and imaging) performed in relation to the first IBD hospital admission was analysed for the total study population and was stratified by IBD type, sex, and age. RESULTS: The majority of the 12 871 patients with IBD included underwent endoscopy (84%), had a biopsy taken (84%), and/or underwent imaging procedures (44%). In total, 7.5% of the population (6% for Crohn’s disease and 8% for ulcerative colitis) were diagnosed with IBD despite not undergoing any of these diagnostic procedures. Patients with Crohn’s disease underwent more procedures than patients with ulcerative colitis (94% vs 92%, p<0.001). Children underwent slightly fewer diagnostic procedures than adults (92% vs 93%, p=0.004). Slightly more men underwent at least one procedure than women (92% vs 94%, p<0.001). CONCLUSION: For 7.5% of patients with IBD, this study did not detect any registrations of the recommended diagnostic procedures for establishing an IBD diagnosis. Further research is needed to examine whether these findings are mainly explained by limitations of the register data or also indicate shortcomings of the general approach to IBD

Impact of sex and socioeconomic status on the likelihood of surgery, hospitalization, and use of medications in inflammatory bowel disease: a systematic review and meta-analysis

BACKGROUND: Inflammatory bowel diseases (IBDs) are associated with high healthcare utilization. This systematic review aimed to summarize what is known about the impact of sex, income, and education on the likelihood of bowel surgery, hospitalization, and use of corticosteroids and biologics among patients with IBD.METHODS: We used EMBASE, MEDLINE, CINAHL, and Web of Science to perform a systematic literature search. Pooled hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random effects meta-analysis for the impact of sex on the likelihood of surgery and hospitalization. In addition, we performed subgroup analyses of the effect of IBD type (Crohn's disease or ulcerative colitis) and age. Finally, meta-regression was undertaken for the year of publication.RESULTS: In total, 67 studies were included, of which 23 studies were eligible for meta-analysis. In the main meta-analysis, male sex was associated with an increased likelihood of bowel surgery (HR 1.42 (95% CI 1.13;1.78), which was consistent with the subgroup analysis for UC only (HR 1.78, 95% CI 1.16; 2.72). Sex did not impact the likelihood of hospitalization (OR 1.05 (95% CI 0.86;1.30), although the subgroup analysis revealed an increased likelihood of hospitalization in CD patients (OR 1.42, 95% CI 1.28;1.58). In 9 of 10 studies, no significant sex-based differences in the use of biologics were reported, although in 6 of 6 studies, female patients had lower adherence to biologics. In 11 of 13 studies, no significant sex-based difference in the use of corticosteroids was reported. The evidence of the impact of income and education on healthcare utilization was sparse and pointed in different directions. The substantial heterogeneity between studies was explained, in part, by differences in IBD type and age.CONCLUSIONS: The results of this systematic review indicate that male patients with IBD are significantly more likely to have surgery than female patients with IBD but are not, overall, more likely to be hospitalized, whereas female patients appear to have statistically significantly lower adherence to biologics compared to male patients. Thus, clinicians should not underestimate the impact of sex on healthcare utilization. Evidence for income- and education-based differences remains sparse.SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022315788.</p