2,097 research outputs found

    A methodology for testing virtualisation security

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    There is a growing interest in virtualisation due to its central role in cloud computing, virtual desktop environments and Green IT. Data centres and cloud computing utilise this technology to run multiple operating systems on one physical server, thus reducing hardware costs. However, vulnerabilities in the hypervisor layer have an impact on any virtual machines running on top, making security an important part of virtualisation. In this paper, we evaluate the security of virtualisation, including detection and escaping the environment. We present a methodology to investigate if a virtual machine can be detected and further compromised, based upon previous research. Finally, this methodology is used to evaluate the security of virtual machines. The methods used to evaluate the security include analysis of known vulnerabilities and fuzzing to test the virtual device drivers on three different platforms: VirtualBox, Hyper-V and VMware ESXI. Our results demonstrate that the attack surface of virtualisation is more prone to vulnerabilities than the hypervisor. Comparing our results with previous studies, each platform withstood IOCTL and random fuzzing, demonstrating that the platforms are more robust and secure than previously found. By building on existing research, the results show that security in the hypervisor has been improved. However, using the proposed methodology in this paper it has been shown that an attacker can easily determine that the machine is a virtual machine, which could be used for further exploitation. Finally, our proposed methodology can be utilised to effectively test the security of a virtualised environment

    A Death in Hollywood: F. Scott Fitzgerald Remembered

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    Flocc: From Agent-Based Models to Interactive Simulations on the Web

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    Agent-based modeling (ABM) is a computational technique wherein systems are represented through the actions and interactions of many individual entities (‘agents’) over time. ABM often attempts to elucidate the unpredictable, high-level behavior of systems through the predictable, low-level behavior of actors within the system. There are currently few software or frameworks for ABM that allow modelers to design and build interactive models on the web, for a wide audience as well as a scientifically literate audience well-versed in complexity, models, and simulations. Flocc is a novel framework for agent-based modeling written in JavaScript, the lingua franca programming language of the web (which can also run on servers or one’s machine). In this paper, we present Flocc’s main features and show how it can be used by scientists, data journalists, web developers, and others to create web-based simulations able to be viewed and interacted with by anyone with a modern web browser. By lowering the barrier to entry to complexity science, we contend that Flocc shows promise as a pedagogical tool as well as a software for exploring complex systems

    A new mutation in the promoter region of the PAX8 gene causes true congenital hypothyroidism with thyroid hypoplasia in a girl with Down's syndrome

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    <b>Background:</b> Thyroid dysfunction is common in newborn infants with Down's syndrome (DS), but defects causing classic thyroid dysgenesis (TD) with permanent congenital hypothyroidism (CH) have not been described.<p></p> <b>Objective:</b> We studied a girl with DS and CH who had a mutation in the promoter sequence of the PAX8 gene.<p></p> <b>Results:</b> A female infant was found to have trisomy 21 and CH, with a venous thyrotropin (TSH) of >150 mU/L and a free thyroxine (fT4) of 15.1 pmol/L (day 12). Thyroid peroxidase antibodies and thyroglobulin antibodies were elevated. Scintigraphy showed normal uptake, but ultrasound identified a small gland with heterogenous echotexture and cystic changes. Sequence analysis of the PAX8 gene revealed a new heterozygous maternally inherited mutation (−3C>T) close to the transcription initiation site. Electromobility shift assay studies of the wild type and the mutant PAX8 sequence incubated with nuclear extracts from PCCL3 cells exhibited that the sequence at position −3 is not involved in specific protein binding. However, the mutant PAX8 promoter showed a significantly reduced transcriptional activation of a luciferase reporter gene in vitro tested in HEK, PCCL3, as well as in HeLa cells, indicating that this mutation is very likely to lead to reduced PAX8 expression.<p></p> <b>Conclusions:</b> The persistent CH in this patient with DS is likely to be attributable to the diminished PAX8 expression due to a new heterozygous mutation in the PAX8 promoter sequence. Our case shows that true CH may occur in DS, as in the general population. Furthermore, it is possible that the trisomy 21 itself may have resulted in a more severe phenotypic expression of the PAX8 mutation in the child than the mother

    Symplectic symmetries of 4-manifolds

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    A study of symplectic actions of a finite group GG on smooth 4-manifolds is initiated. The central new idea is the use of GG-equivariant Seiberg-Witten-Taubes theory in studying the structure of the fixed-point set of these symmetries. The main result in this paper is a complete description of the fixed-point set structure (and the action around it) of a symplectic cyclic action of prime order on a minimal symplectic 4-manifold with c12=0c_1^2=0. Comparison of this result with the case of locally linear topological actions is made. As an application of these considerations, the triviality of many such actions on a large class of 4-manifolds is established. In particular, we show the triviality of homologically trivial symplectic symmetries of a K3K3 surface (in analogy with holomorphic automorphisms). Various examples and comments illustrating our considerations are also included.Comment: 28 pages, 1 figure, 1 appendix, publishe

    A Comparison of Chiropractic Students\u27 Learning Styles Based on Admission Status

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    Due to recent regulation, Chiropractic Colleges admit students with less than standard science courses and less than standard GPA. These students require tracking and support. How these students learn compared to standard admissions students is not understood. Researchers have demonstrated that students\u27 learning approaches, strategies, and preferences vary based on educational background and culture and are related to performance. The purpose of this study was to better understand chiropractic students learning styles based on admissions status informing supportive efforts. The theoretical framework was based on Curry\u27s work describing elements of learning on a spectrum from stable to flexible. In this cross-sectional quantative study, data were collected using 3 validated instruments (Approaches and Study Skills Inventory for Students (ASSIST), Learning and Study Strategies Inventory (LASSI), and the Visual, Aural, Read/Write, and Kinesthetic (VARK) questionaire). The sample included all incoming students over 4 consecutive terms;195 entrants with 165 participants. Consistent with prior studies, analysis utilizing Pearson chi-square test of independence, revealed students with less science tend toward some surface learning approaches including: a significant difference in ASSIST subscale unrelated memorizing (p =.023) and a difference approaching significance for subscale syllabus boundness (p = .058). For students with a lower GPA, report frequencies of significance or approaching significance as a relative strength include: LASSI scale self-regulation (p =.029), and subscales concentration (p =.023) and use of study aids (p =.051). Admitting students from varying educational backgrounds, enables chiropractic colleges to include more underrepresented students. This study provided needed information to support these students

    First North American case of Hemoglobin Shepherds Bush (β 74[E18] Gly → Asp) in a central Pennsylvania family

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    BACKGROUND: Hemoglobin Shepherds Bush (Human Genome Variation Society name: HBB:c.224G > A) is an unstable hemoglobin variant resulting from a β 74 GGC to GAC mutation (Gly to Asp) that manifests clinically as hemolytic anemia or gall bladder disease due to chronic subclinical hemolysis. CASE PRESENTATION: We report a Pennsylvania family of English descent with this condition, first noticed in a 6-year-old female. The proband presented with splenomegaly, fatigue, dark urine and an elevated indirect bilirubin. Hemoglobin identification studies and subsequent genetic testing performed according to a systematic algorithm elucidated the diagnosis of Hb Shepherds Bush. CONCLUSIONS: This is the first case of this rare hemoglobin variant identified in North America to our knowledge. It was identified using a systematic algorithm of diagnostic tests that should be followed whenever considering a rare hemoglobinopathy as part of the differential diagnosis

    Hydrator Therapies for Chronic Bronchitis. Lessons from Cystic Fibrosis

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    Patients with the chronic bronchitis form of chronic obstructive pulmonary disease and cystic fibrosis share similar clinical features, including mucus obstruction of airways and the development of chronic/recurrent airways infections that often manifest as disease exacerbations. There is growing evidence that these diseases may have parallels in disease pathogenesis as well, including cystic fibrosis transmembrane conductance regulator dysfunction, mucus dehydration, and defective mucociliary clearance. As progress is made in the development of therapies that target the basic defects that lead to cystic fibrosis lung disease, it is possible that similar approaches could also benefit patients with chronic bronchitis. A deeper understanding of how tobacco smoke and other triggers of chronic bronchitis actually lead to disease, and exploration of the concept that therapies that restore cystic fibrosis transmembrane conductance regulator function, mucus hydration, and/or mucociliary clearance may benefit patients with chronic bronchitis, hold the prospect of significant progress in treating this prevalent disease

    Soluble Mediators, Not Cilia, Determine Airway Surface Liquid Volume in Normal and Cystic Fibrosis Superficial Airway Epithelia

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    A key aspect of the lung's innate defense system is the ability of the superficial epithelium to regulate airway surface liquid (ASL) volume to maintain a 7-μm periciliary liquid layer (PCL), which is required for cilia to beat and produce mucus flow. The mechanisms whereby airway epithelia regulate ASL height to ≥7 μm are poorly understood. Using bumetanide as an inhibitor of Cl− secretion, and nystatin as an activator of Na+ absorption, we found that a coordinated “blending” of both Cl− secretion and Na+ absorption must occur to effect ASL volume homeostasis. We then investigated how ASL volume status is regulated by the underlying epithelia. Cilia were not critical to this process as (a) ASL volume was normal in cultures from patients with primary ciliary dyskinesia with immotile cilia, and (b) in normal cultures that had not yet undergone ciliogenesis. However, we found that maneuvers that mimic deposition of excess ASL onto the proximal airways, which occurs during mucociliary clearance and after glandular secretion, acutely stimulated Na+ absorption, suggesting that volume regulation was sensitive to changes in concentrations of soluble mediators in the ASL rather than alterations in ciliary beating. To investigate this hypothesis further, we added potential “soluble mediators” to the ASL. ASL volume regulation was sensitive to a channel-activating protein (CAP; trypsin) and a CAP inhibitor (aprotinin), which regulated Na+ absorption via changes in epithelial Na+ channel (ENaC) activity in both normal and cystic fibrosis cultures. ATP was also found to acutely regulate ASL volume by inducing secretion in normal and cystic fibrosis (CF) cultures, while its metabolite adenosine (ADO) evoked secretion in normal cultures but stimulated absorption in CF cultures. Interestingly, the amount of ASL/Cl− secretion elicited by ATP/ADO was influenced by the level of CAP-induced Na+ absorption, suggesting that there are important interactions between the soluble regulators which finely tune ASL volume
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