Information Flow Control for Secure Cloud Computing Bacon, Jean; Eyers, David; Pasquier, Thomas F. J-M ...
IEEE eTransactions on network and service management,
03/2014, Volume:
11, Issue:
1
Journal Article
Peer reviewed
Open access
Security concerns are widely seen as an obstacle to the adoption of cloud computing solutions. Information Flow Control (IFC) is a well understood Mandatory Access Control methodology. The earliest ...IFC models targeted security in a centralised environment, but decentralised forms of IFC have been designed and implemented, often within academic research projects. As a result, there is potential for decentralised IFC to achieve better cloud security than is available today. In this paper we describe the properties of cloud computing-Platform-as-a-Service clouds in particular-and review a range of IFC models and implementations to identify opportunities for using IFC within a cloud computing context. Since IFC security is linked to the data that it protects, both tenants and providers of cloud services can agree on security policy, in a manner that does not require them to understand and rely on the particulars of the cloud software stack in order to effect enforcement.
A model of cloud services is emerging whereby a few trusted providers manage the underlying hardware and communications whereas many companies build on this infrastructure to offer higher level, ...cloud-hosted PaaS services and/or SaaS applications. From the start, strong isolation between cloud tenants was seen to be of paramount importance, provided first by virtual machines (VM) and later by containers, which share the operating system (OS) kernel. Increasingly it is the case that applications also require facilities to effect isolation and protection of data managed bythose applications. They also require flexible data sharingwith other applications, often across the traditional cloud-isolation boundaries; for example, when government, consisting of different departments, provides services to its citizens through a common platform. These concerns relate to the management of data. Traditional access control is application and principal/role specific, applied at policy enforcement points, after which there is no subsequent control over where data flows;a crucial issue once data has left its owner's control by cloud-hosted applications andwithin cloud-services. Information Flow Control (IFC), in addition, offers system-wide, end-to-end, flow control based on the properties of the data. We discuss the potential of clouddeployed IFC for enforcingowners' data flow policy with regard to protection and sharing, aswell as safeguarding against malicious or buggy software. In addition, the audit log associated with IFC provides transparency and offers system-wide visibility over data flows. This helps those responsible to meet their data management obligations, providing evidence of compliance, and aids in the identification ofpolicy errors and misconfigurations. We present our IFC model and describe and evaluate our IFC architecture and implementation (CamFlow). This comprises an OS level implementation of IFC with support for application management, together with an IFC-enabled middleware.
Abstract Aim Patients with diabetes have shown lower performance in tests of cognitive function especially those testing memory, executive functions, and psychomotor efficiency. They also have an ...elevated risk of both vascular dementia and Alzheimer's disease. Cognitive impairment may have consequence on treatment compliance. Methods and results This article provides indication for holding an interview, and reports a few screening bedside tests to detect a cognitive impairment. Some neuropsychological tests useful for characterizing the cognitive profile of a patient are described, as well as the main cognitive profiles expected in patients with diabetes and cognitive decline. Conclusion A systematic assessment of cognition with a rapid interview and screening tests in patients with diabetes, especially the oldest, with a long history of diabetes, co-morbidities, or with unexplained poor metabolic control would be a good clinical practice. Patients with cognitive decline may be referred to memory clinics for identifying the cause of the decline and contribute to provide appropriate medical and medicosocial management.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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Sleep disorders in aging and dementia Bombois, S.; Derambure, P.; Pasquier, F. ...
The Journal of nutrition, health & aging,
03/2010, Volume:
14, Issue:
3
Journal Article
Peer reviewed
Open access
This paper reviews the characteristics of sleep disorders found in people at a greater risk of dementia: the elderly adult, patients with mild cognitive impairment (MCI) and those with ...neurodegenerative diseases. The frequency of sleep architecture modifications and circadian rhythm sleep disturbances increases with age. Although around 40% of older adults complain of poor sleep, true sleep disorders are far less prevalent in healthy older adults and are frequently associated with comorbidities. The sleep disorders observed in Alzheimer’s disease (AD) patients are often similar to (but more intense than) those found in non-demented elderly people. Poor sleep results in an increased risk of significant morbidities and even mortality in demented patients and constitutes a major source of stress for caregivers. The prevalence of primary sleep disorders such as rapid eye movement (REM) sleep behavior disorders (RBDs), restless legs syndrome (RLS), periodic limb movements (PLMs) and sleep-disordered breathing increases with age. There are no published data on RLS and PLMs in demented persons but RBDs and sleep apnea syndrome have been studied more extensively. In fact, RBDs are suggestive of Lewy body dementia (LBD) and are predictive for neurodegeneration in Parkinson’s disease. Obstructive sleep apnea (OSA) shares common risk factors with AD and may even be an integral part of the pathological process in AD. In MCI patients, the hypotheses in which (i) sleep disorders may represent early predictive factors for progression to dementia and (ii) MCI is symptomatic of a non-diagnosed sleep disorder remain to be elucidated. Guidelines for drug and non-drug treatments of sleep disorders in the elderly and in demented patients are also considered in this review. In healthy but frail elderly people and in early-stage AD patients, sleep should be more thoroughly characterized (notably by using standardized interviews and polysomnographic recording).
Frontotemporal lobar degeneration (FTLD) encompasses a variety of clinicopathologic entities. The antemortem prediction of the underlying pathologic lesions is reputed to be difficult. This study ...sought to characterize correlations between 1) the different clinical variants of primary progressive language and speech disorders and 2) the pathologic diagnosis.
The latter was available for 18 patients having been prospectively monitored in the Lille Memory Clinic (France) between 1993 and 2008.
The patients were diagnosed with progressive anarthria (n = 5), agrammatic progressive aphasia (n = 6), logopenic progressive aphasia (n = 1), progressive jargon aphasia (n = 2), typical semantic dementia (n = 2), and atypical semantic dementia (n = 2). All patients with progressive anarthria had a tau pathology at postmortem evaluation: progressive supranuclear palsy (n = 2), Pick disease (n = 2), and corticobasal degeneration (n = 1). All patients with agrammatic primary progressive aphasia had TDP-43-positive FTLD (FTLD-TDP). The patients with logopenic progressive aphasia and progressive jargon aphasia had Alzheimer disease. Both cases of typical semantic dementia had FTLD-TDP. The patients with atypical semantic dementia had tau pathologies: argyrophilic grain disease and corticobasal degeneration.
The different anatomic distribution of the pathologic lesions could explain these results: opercular and subcortical regions in tau pathologies with progressive anarthria, the left frontotemporal cortex in TDP-43-positive frontotemporal lobar degeneration (FTLD-TDP) with agrammatic progressive aphasia, the bilateral lateral and anterior temporal cortex in FTLD-TDP or argyrophilic grain disease with semantic dementia, and the left parietotemporal cortex in Alzheimer disease with logopenic progressive aphasia or jargon aphasia. These correlations have to be confirmed in larger series.
Since the first descriptions of circumscribed frontotemporal atrophies, and the first statement published by the Lund and Manchester groups, consensus clinical and pathological criteria for ...frontotemporal dementia (FTD) have been increasingly refined. The last international behavioural variant FTD criteria (FTDC) (Rascovsky et al., 2011) are the most sensitive, operational and reliable, for the clinical syndrome. Previously exclusion features, like early and severe amnestic syndrome or spatial disorientation, which turn out to be not so rare, are taken into account, as well as imaging, and biomarkers suggestive of other pathologies like Alzheimer's disease. So far, clinical features do not seem very helpful in predicting the underlying histopathology, although there are some clues, mainly related to neurological features (e.g. motor neuron disease, extra-pyramidal symptoms or language disorders), or associated disorders (e.g. Paget disease of bone) or genetics. BvFTD remains a difficult diagnosis at very early stage, which accounts for the delay of diagnosis, especially in late onset, where the frontotemporal atrophy may not be striking. At very young onset, psychiatric diseases must be ruled out. More systematic assessment of social cognition could be helpful. Further biomarkers are expected. Systematic use of recent criteria, for BvFTD and other neurodegenerative diseases especially AD, will contribute to make early and correct diagnoses in excluding or suggesting alternative diagnoses. Post-mortem assessment, with detailed recording of clinical information, is essential to progress.
Depuis les premières descriptions des atrophies lobaires fronto-temporales et les premiers critères établis par les groupes de Lund et Manchester, les critères de démence fronto-temporales (DFT) ne cessent de s’améliorer. Les derniers critères du consensus international de variante frontale (vf) de DFT (Rascovsky et al., 2011) ont une meilleure sensibilité, fiabilité inter-observateur et sont plus opérationnels que les précédents pour le syndrome clinique. Les critères d’exclusions antérieurs comme le syndrome amnésique précoce et sévère ou la désorientation spatiale, qui ne s’avèrent pas si rares, sont maintenant pris en compte, comme l’imagerie et les biomarqueurs évocateurs d’autres pathologies comme la maladie d’Alzheimer. Les signes cliniques ne semblent pas très utiles pour orienter vers la neuropathologie sous-jacente, bien qu’il existe quelques indices, principalement neurologiques (comme l’atteinte du motoneurone, les symptômes extrapyramidaux ou les troubles du langage), ou des pathologies associées (comme une maladie de Paget) ou génétiques. La vf-DFT reste un diagnostic difficile au stade très précoce, ce qui explique le retard de diagnostic, en particulier, en cas de survenue tardive, où l’atrophie fronto-temporale peut ne pas être notable. Quand quelle survient chez les sujets jeunes, les maladies psychiatriques doivent être écartées. Une évaluation plus systématique de la cognition sociale pourrait être utile. D’autres biomarqueurs sont attendus. L’utilisation systématique des critères récents, non seulement de vf-DFT mais aussi d’autres démences et notamment de la maladie d’Alzheimer, contribuera au diagnostic précoce et précis des vf-DFT en excluant ou en suggérant d’autres diagnostics. L’examen post-mortem et le recueil précis des informations cliniques sont essentiels pour progresser.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
To compare the power of tests assessing different cognitive domains for the identification of prodromal Alzheimer disease (AD) among patients with mild cognitive impairment (MCI).
Given the early ...involvement of the medial temporal lobe, a precocious and specific pattern of memory disorders might be expected for the identification of prodromal AD.
A total of 251 patients with MCI were tested at baseline by a standardized neuropsychological battery, which included the Free and Cued Selective Recall Reminding Test (FCSRT) for verbal episodic memory; the Benton Visual Retention Test for visual memory; the Deno 100 and verbal fluency for language; a serial digit learning test and the double task of Baddeley for working memory; Wechsler Adult Intelligence Scale (WAIS) similarities for conceptual elaboration; and the Stroop test, the Trail Making test, and the WAIS digit symbol test for executive functions. The patients were followed at 6-month intervals for up to 3 years in order to identify those who converted to AD vs those who remained stable over time. Statistical analyses were based on receiver operating characteristic curve and Cox proportional hazards models.
A total of 59 subjects converted to AD dementia. The most sensitive and specific test for diagnosis of prodromal AD was the FCSRT. Significant cutoff for the diagnosis was 17/48 for free recall, 40/48 for total recall, and below 71% for index of sensitivity of cueing (% of efficacy of semantic cues for retrieval).
The amnestic syndrome of the medial temporal type, defined by the Free and Cued Selective Recall Reminding Test, is able to distinguish patients at an early stage of Alzheimer disease from mild cognitive impairment non-converters.
Alzheimer's disease (AD) and diabetes mellitus (DM) are two of the most common and devastating health problems in the elderly. They share a number of common features amongst which high prevalence ...after 65 years, important impact of patient's quality of life, substantial health care costs. Reviews on the epidemiological studies on cognitive impairment in patients with DM found evidence of cross-sectional and prospective associations between type 2 DM and moderate cognitive impairment, on memory and executive functions. There is also evidence for an elevated risk of both vascular dementia and AD in patients with type 2 DM, albeit with strong interaction of other factors such as hypertension, dyslipidaemia and ApoE genotype. DM is an independent predictor of post-stroke dementia. DM being an atherogenic risk factor, it may increase the risk of dementia through associations with stroke, causing vascular dementia. In addition, vascular reactivity may be adversely affected by advanced glycosylation end products resulting in more subtle perfusion abnormalities. Cerebrovascular disease may exacerbate AD through direct interactions between the two pathological processes or through cognitive impairment secondary to cerebrovascular disease “unmasking” AD at an earlier stage than it would otherwise become apparent. The increased risk of AD may also be mediated by the exacerbation of β-amyloid neurotoxicity by advanced glycosyla-tion end products identified in the matrix of neurofibrillary tangles and amyloid plaques in AD brains, or associations with insulin functions. Decreased cholinergic transport across the blood-brain barrier observed in diabetic animals may exacerbate cognitive impairment in AD. Many interventions could reduce the cognitive decline associated with DM, yet not enough are taken into account so far.
Démences et diabète sucré
La maladie d'Alzheimer (MA) et le diabète (DM) sont deux affections chroniques fréquentes chez les sujets âgés. Elles ont toutes deux une prévalence élevée après 65 ans, un fort retentissement sur la qualité de vie des patients et ont un impact médico-économique majeur. La revue des études épidémiologiques sur les altérations cognitives des patients diabétiques suggère l'existence d'une association entre diabète de type 2 et troubles cognitifs modérés. Une telle relation existe aussi entre diabète de type 2, démence vasculaire et MA mais avec une forte influence d'autres facteurs comme l'hypertension artérielle, la dyslipémie ou le polymorphisme de l'ApoE. Le diabète est un facteur de risque indépendant de démence survenant après un accident vasculaire cérébral. Le diabète agit comme agent athérogène et entraîne des anomalies de la réactivité vasculaire par l'action des produits de la glycation avancée sur la paroi des vaisseaux. La maladie cérébro-vasculaire peut favoriser l'expression de la MA soit par interaction directe entre les deux affections, soit en démasquant plus précocement les troubles cognitifs. Le risque de MA peut aussi être médié par l'accentuation par les produits de la glycation avancée de la neurotoxicité des dépôts amyloïdes dans les cerveaux de MA. La baisse du transport cholinergique à travers la barrière hématocérébrale, observée chez l'animal diabétique, pourrait influencer les troubles cognitifs de la MA. Certaines interventions, insuffisamment utilisées, pourraient ralentir le déclin cognitif du sujet diabétique.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
MRI is more sensitive than CT for detection of age-related white matter changes (ARWMC). Most rating scales estimate the degree and distribution of ARWMC either on CT or on MRI, and they differ in ...many aspects. This makes it difficult to compare CT and MRI studies. To be able to study the evolution and possible effect of drug treatment on ARWMC in large patient samples, it is necessary to have a rating scale constructed for both MRI and CT. We have developed and evaluated a new scale and studied ARWMC in a large number of patients examined with both MRI and CT.
Seventy-seven patients with ARWMC on either CT or MRI were recruited and a complementary examination (MRI or CT) performed. The patients came from 4 centers in Europe, and the scans were rated by 4 raters on 1 occasion with the new ARWMC rating scale. The interrater reliability was evaluated by using kappa statistics. The degree and distribution of ARWMC in CT and MRI scans were compared in different brain areas.
Interrater reliability was good for MRI (kappa=0.67) and moderate for CT (kappa=0.48). MRI was superior in detection of small ARWMC, whereas larger lesions were detected equally well with both CT and MRI. In the parieto-occipital and infratentorial areas, MRI detected significantly more ARWMC than did CT. In the frontal area and basal ganglia, no differences between modalities were found. When a fluid-attenuated inversion recovery sequence was used, MRI detected significantly more lesions than CT in frontal and parieto-occipital areas. No differences were found in basal ganglia and infratentorial areas.
We present a new ARWMC scale applicable to both CT and MRI that has almost equal sensitivity, except for certain regions. The interrater reliability was slightly better for MRI, as was the detectability of small lesions.
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