68 research outputs found
Collective responsibility and mutual coercion in IoT botnets: a tragedy of the commons problem
In recent years, several cases of DDoS attacks using IoT botnets have been reported, including the largest DDoS known, caused by the malware Mirai in 2016. The infection of the IoT devices could have been prevented with basic security hygiene, but as the actors responsible to apply these preventative measures are not the main target but just âenablersâ of the attack their incentive is little. In most cases they will even be unaware of the situation. Internet, as a common and shared space allows also some costs to be absorbed by the community rather than being a direct consequence suffered by those that behave insecurely. This paper analyses the long term effects of the prevalence of a system where individual decision-making systematically causes net harm. An analogy with âthe tragedy of the commonsâ problem is done under the understanding that rational individuals seek the maximization of their own utility, even when this damages shared resources.
Four areas of solution are proposed based on the review of this problem in different contexts. It was found necessary to include non-technical solutions and consider human behaviour. This opens a discussion about a multidisciplinary focus in IoT cyber security
JMFit : A SAS Macro for Joint Models of Longitudinal and Survival Data
Joint models for longitudinal and survival data now have a long history of being used in clinical trials or other studies in which the goal is to assess a treatment effect while accounting for a longitudinal biomarker such as patient-reported outcomes or immune responses. Although software has been developed for fitting the joint model, no software packages are currently available for simultaneously fitting the joint model and assessing the fit of the longitudinal component and the survival component of the model separately as well as the contribution of the longitudinal data to the fit of the survival model. To fulfill this need, we develop a SAS macro, called JMFit. JMFit implements a variety of popular joint models and provides several model assessment measures including the decomposition of AIC and BIC as well as ÎAIC and ÎBIC recently developed in Zhang et al. (2014). Examples with real and simulated data are provided to illustrate the use of JMFit
An Indicators-of-Risk Library for Industrial Network Security
This paper introduces an âIndicator of Risk (IoR) Library" that leverages the MITRE ATT&CK for Industrial Control Systems (ICS) knowledge base to support continuous risk monitoring. This allows also making use of variables that are already being monitored to analyse risks in a continuous basis. IoRs broaden the concept of Indicators of Compromise by combining detection strategies with probabilistic inference as a tool for quantifying cyber-security risks. The latest version of the Library has 95 IoRs and has been reviewed by professionals from three major companies and cross-referenced against detection use-cases implemented by other researchers to validate its potential to identify variables for monitoring cyber-risks in ICS
Assessing model fit in joint models of longitudinal and survival data with applications to cancer clinical trials
Joint models for longitudinaland survival data now have along history of being used in clinical trials or other studies in which the goal is to assess a treatment effect while accounting for longitudinal assessments such as patient-reported outcomes or tumor response. Compared to using survival data alone,the joint modeling of survival and longitudinal data allows for estimation of direct and indirect treatment effects, thereby resulting in improved efficacy assessment. Although global fit indices such as AIC or BIC can be used to rank joint models, these measures do not provide separate assessments of each component of the joint model. In this paper, we develop a novel decomposition of AIC and BIC (i.e., AIC = AICLong + AICSurv|Long and BIC = BICLong + BICSurv|Long) that allows us to assess the fit of each component of the joint model, and in particular to assess the fit of the longitudinal component of the model and the survival component separately. Based on this decomposition, we then propose ÎAICSurv and ÎBICSurv to determine the importance and contribution of the longitudinal data to the model fit of the survival data. Moreover, this decomposition, along with ÎAICSurv and ÎBICSurv, is also quite useful in comparing, for example, trajectory-based joint models and shared parameter joint models and deciding which type of model best fits the survival data. We examine a detailed case study in mesothelioma to apply our proposed methodology along with an extensive set of simulation studies
GLPâ1 Promotes Cortical and Medullary Perfusion in the Human Kidney and Maintains Renal Oxygenation During NaCl Loading
BackgroundGLPâ1 (glucagonâlike peptideâ1) receptor agonists exert beneficial longâterm effects on cardiovascular and renal outcomes. In humans, the natriuretic effect of GLPâ1 depends on GLPâ1 receptor interaction, is accompanied by suppression of angiotensin II, and is independent of changes in renal plasma flow. In rodents, angiotensin II constricts vasa recta and lowers medullary perfusion. The current randomized, controlled, crossover study was designed to test the hypothesis that GLPâ1 increases renal medullary perfusion in healthy humans.Methods and ResultsHealthy male participants (n=10, aged 27Âą4âyears) ingested a fixed sodium intake for 4âdays and were examined twice during a 1âhour infusion of either GLPâ1 (1.5âpmol/kg per minute) or placebo together with infusion of 0.9% NaCl (750âmL/h). Interleaved measurements of renal arterial blood flow, oxygenation (R2*), and perfusion were acquired in the renal cortex and medulla during infusions, using magnetic resonance imaging. GLPâ1 infusion increased medullary perfusion (32Âą7%, P<0.001) and cortical perfusion (13Âą4%, P<0.001) compared with placebo. Here, NaCl infusion decreased medullary perfusion (â5Âą2%, P=0.007), whereas cortical perfusion remained unchanged. R2* values increased by 3Âą2% (P=0.025) in the medulla and 4Âą1% (P=0.008) in the cortex during placebo, indicative of decreased oxygenation, but remained unchanged during GLPâ1. Blood flow in the renal artery was not altered significantly by either intervention.ConclusionsGLPâ1 increases predominantly medullary but also cortical perfusion in the healthy human kidney and maintains renal oxygenation during NaCl loading. In perspective, suppression of angiotensin II by GLPâ1 may account for the increase in regional perfusion
Ab-Externo AAV-Mediated Gene Delivery to the Suprachoroidal Space Using a 250 Micron Flexible Microcatheter
The current method of delivering gene replacement to the posterior segment of the eye involves a three-port pars plana vitrectomy followed by injection of the agent through a 37-gauge cannula, which is potentially wrought with retinal complications. In this paper we investigate the safety and efficacy of delivering adeno-associated viral (AAV) vector to the suprachoroidal space using an ab externo approach that utilizes an illuminated microcatheter.6 New Zealand White rabbits and 2 Dutch Belted rabbits were used to evaluate the ab externo delivery method. sc-AAV5-smCBA-hGFP vector was delivered into the suprachoroidal space using an illuminated iTrackTM 250A microcatheter. Six weeks after surgery, the rabbits were sacrificed and their eyes evaluated for AAV transfection using immunofluorescent antibody staining of GFP.Immunostaining of sectioned and whole-mounted eyes demonstrated robust transfection in all treated eyes, with no fluorescence in untreated control eyes. Transfection occurred diffusely and involved both the choroid and the retina. No apparent adverse effects caused by either the viral vector or the procedure itself could be seen either clinically or histologically.The ab externo method of delivery using a microcatheter was successful in safely and effectively delivering a gene therapy agent to the suprachoroidal space. This method presents a less invasive alternative to the current method of virally vectored gene delivery
Joint modeling of longitudinal outcomes and survival using latent growth modeling approach in a mesothelioma trial
Joint modeling of longitudinal and survival data can provide more efficient and less biased estimates of treatment effects through accounting for the associations between these two data types. Sponsors of oncology clinical trials routinely and increasingly include patient-reported outcome (PRO) instruments to evaluate the effect of treatment on symptoms, functioning, and quality of life. Known publications of these trials typically do not include jointly modeled analyses and results. We formulated several joint models based on a latent growth model for longitudinal PRO data and a Cox proportional hazards model for survival data. The longitudinal and survival components were linked through either a latent growth trajectory or shared random effects. We applied these models to data from a randomized phase III oncology clinical trial in mesothelioma. We compared the results derived under different model specifications and showed that the use of joint modeling may result in improved estimates of the overall treatment effect
Goal-directed haemodynamic therapy during general anaesthesia for noncardiac surgery:a systematic review and meta-analysis
BACKGROUND: During general anaesthesia for noncardiac surgery, there remain knowledge gaps regarding the effect of goal-directed haemodynamic therapy on patient-centred outcomes. METHODS: Included clinical trials investigated goal-directed haemodynamic therapy during general anaesthesia in adults undergoing noncardiac surgery and reported at least one patient-centred postoperative outcome. PubMed and Embase were searched for relevant articles on March 8, 2021. Two investigators performed abstract screening, full-text review, data extraction, and bias assessment. The primary outcomes were mortality and hospital length of stay, whereas 15 postoperative complications were included based on availability. From a main pool of comparable trials, meta-analyses were performed on trials with homogenous outcome definitions. Certainty of evidence was evaluated using Grading of Recommendations, Assessment, Development, and Evaluations (GRADE). RESULTS: The main pool consisted of 76 trials with intermediate risk of bias for most outcomes. Overall, goal-directed haemodynamic therapy might reduce mortality (odds ratio=0.84; 95% confidence interval [CI], 0.64 to 1.09) and shorten length of stay (mean difference=â0.72 days; 95% CI, â1.10 to â0.35) but with low certainty in the evidence. For both outcomes, larger effects favouring goal-directed haemodynamic therapy were seen in abdominal surgery, very high-risk surgery, and using targets based on preload variation by the respiratory cycle. However, formal tests for subgroup differences were not statistically significant. Goal-directed haemodynamic therapy decreased risk of several postoperative outcomes, but only infectious outcomes and anastomotic leakage reached moderate certainty of evidence. CONCLUSIONS: Goal-directed haemodynamic therapy during general anaesthesia might decrease mortality, hospital length of stay, and several postoperative complications. Only infectious postoperative complications and anastomotic leakage reached moderate certainty in the evidence
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