371 research outputs found

    A Multi-Agent Approach to Advanced Persistent Threat Detection in Networked Systems

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    Advanced cyber threats that are well planned, funded and stealthy are an increasing issue facing secure networked systems. As our reliance on protected networked systems continues to grow, the motivation for developing new malicious techniques that cannot be easily detected by traditional signature-based systems, and that make use of previously unseen zero-day vulnerabilities, continues to grow. Lack of adaptivity, extended data-collection and generalised algorithms to detect stealthy attacks is contributing to the insecurity of modern networked systems. To protect these networks, new approaches that can monitor and respond to indicators of compromise in a reflective way that considers all of the available evidence rather than individual points of data is required. This thesis presents a novel approach to intrusion detection and specifically focuses on detecting advanced persistent threats which are characteristically stealthy and evasive attacks. This approach offers a multi-agent model for automatically collecting, analysing and classifying data in a distributed way that considers the context in which the data was found. Using a context-based classification that considers the likelihood of a data-point being a false alarm or legitimate is used to decrease the prevalence of erroneous classifications and regulate continuation of the data collection process. Using this architecture, a detection rate increase of up to 20% is achieved in false alarm environments and an efficiency increase of up to 50% made over traditional monolithic intrusion detection systems. Additionally, the shortcomings of algorithms to detect stealthy attacks are addressed by providing a generalised anomaly detection algorithm for detecting the initial traces of an attack and deploying the proposed multi-agent model to investigate the attack further. The generalised algorithms can detect a wide variety of network-based attacks at an average detection rate of 85% providing an accurate and scalable way to detect the initial traces of compromise. The main novelty of this thesis is providing systems for detecting attacks where the threat model is increasingly stealthy and assumed capable of bypassing traditional signature-based approaches. The multi-agent architecture is unique in its ability, and the generalised anomaly detection algorithm is novel in detecting a variety of different cyber attacks from the network-flow layer. The evidence from this research suggests that context-based evidence gathering can provide a more efficient approach to analysing data and the generalised anomaly detection algorithm can be applied widely to detect attack indicators

    Occurrence of Didymella ascospores in western and southern Poland in 2004–2006

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    The concentration of airborne Didymella spores has been investigated at two monitoring sites situated along the west–south transect in Poland (Szczecin, Kraków), i.e. from a height of 100 to 219 m, respectively, above sea level. The aerobiological monitoring of fungal spores was performed by means of two Lanzoni volumetric spore traps. The high Didymella spore numbers were observed at both cities in June, July and August. Statistically significant correlations have been found mainly between the Didymella spore concentrations in the air and the minimum air temperature and relative air humidity. The spore count of Didymella is determined by the diversity of local flora and weather conditions, especially by the relative air humidity. The identification of factors that influence and shape spore concentrations may significantly improve the current methods of allergy prevention

    Onset of relief of dyspnoea with budesonide/formoterol or salbutamol following methacholine-induced severe bronchoconstriction in adults with asthma: a double-blind, placebo-controlled study

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    BACKGROUND: The long-acting β(2)-agonist (LABA) formoterol has an onset of effect comparable to that of salbutamol. Consequently, the combination of formoterol and budesonide in one inhaler, approved for maintenance use, can potentially be used for reliever therapy. This study compared the onset of relief from induced bronchospasm with a single dose of budesonide/formoterol versus standard salbutamol therapy in patients with asthma. METHODS: In this randomised, double-blind, placebo-controlled, cross-over study, 32 patients with asthma underwent a methacholine provocation test leading to a fall in forced expiratory volume in 1 second (FEV(1)) of ≥30% at enrolment (Visit 1) and three subsequent study visits (Visits 2–4). Immediately after each provocation at Visits 2–4, patients received one of three test treatments: one inhalation of budesonide/formoterol 160/4.5 μg (via Turbuhaler(®)), two inhalations of salbutamol 100 μg (via a pressurised metered-dose inhaler [pMDI]) or placebo. All patients received each of the test treatments in a randomised order, after separate methacholine provocations. The effect of treatment on FEV(1 )and breathlessness (using the Borg scale) was measured at 1, 3, 5, 10, 15, 20, 25 and 30 minutes after test treatment. RESULTS: Following methacholine provocation, Borg score increased from a baseline value of below 0.5 to 3.03, 3.31 and 3.50 before treatment with budesonide/formoterol, salbutamol and placebo, respectively. Budesonide/formoterol and salbutamol reversed methacholine-induced dyspnoea (breathlessness) rapidly. At 1 minute after inhalation, statistically significant decreases in Borg score were observed for budesonide/formoterol and salbutamol (p = 0.0233 and p < 0.0001, respectively, versus placebo), with similar rapid increases in FEV(1 )(both active treatments p < 0.0001 versus placebo). The median time to 50% recovery in Borg score after methacholine provocation was 3 minutes with budesonide/formoterol, 2 minutes with salbutamol and 10 minutes with placebo. All treatments and procedures were well tolerated. CONCLUSION: Single doses of budesonide/formoterol and salbutamol both provided rapid relief of dyspnoea and reversal of severe airway obstruction in patients with asthma with experimentally induced bronchoconstriction. The perception of relief, as confirmed by objective lung function assessment, provides evidence that budesonide/formoterol can be used as reliever medication in asthma

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Peritrophic matrix of Phlebotomus duboscqi and its kinetics during Leishmania major development

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    Light microscopy of native preparations, histology, and electron microscopy have revealed that Phlebotomus duboscqi belongs to a class of sand fly species with prompt development of the peritrophic matrix (PM). Secretion of electron-lucent fibrils, presumably chitin, starts immediately after the ingestion of a blood meal and, about 6 h later, is followed by secretion of amorphous electron-dense components, presumably proteins and glycoproteins. The PM matures in less than 12 h and consists of a thin laminar outer layer and a thick amorphous inner layer. No differences have been found in the timing of the disintegration of the PM in females infected with Leishmania major. In both groups of females (infected and uninfected), the disintegration of the PM is initiated at the posterior end. Although parasites are present at high densities in the anterior part of the blood meal bolus, they escape from the PM at the posterior end only. These results suggest that L. major chitinase does not have an important role in parasite escape from the PM. Promastigotes remain in the intraperitrophic space until the PM is broken down by sand-fly-derived chitinases and only then migrate anteriorly. Disintegration of the PM occurs simultaneously with the morphological transformation of parasites from procyclic forms to long nectomonads. A novel role is ascribed to the anterior plug, a component of the PM secreted by the thoracic midgut; this plug functions as a temporary barrier to stop the forward migration of nectomonads to the thoracic midgut

    First Detection of Leishmania major DNA in Sergentomyia (Spelaeomyia) darlingi from Cutaneous Leishmaniasis Foci in Mali

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    Leishmania major complex is the main causative agent of zoonotic cutaneous leishmaniasis (ZCL) in the Old World. Phlebotomus papatasi and Phlebotomus duboscqi are recognized vectors of L. major complex in Northern and Southern Sahara, respectively. In Mali, ZCL due to L. major is an emerging public health problem, with several cases reported from different parts of the country. The main objective of the present study was to identify the vectors of Leishmania major in the Bandiagara area, in Mali. Methodology/Principal Findings: An entomological survey was carried out in the ZCL foci of Bandiagara area. Sandflies were collected using CDC miniature light traps and sticky papers. In the field, live female Phlebotomine sandflies were identified and examined for the presence of promastigotes. The remaining sandflies were identified morphologically and tested for Leishmania by PCR in the ITS2 gene. The source of blood meal of the engorged females was determined using the cyt-b sequence. Out of the 3,259 collected sandflies, 1,324 were identified morphologically, and consisted of 20 species, of which four belonged to the genus Phlebotomus and 16 to the genus Sergentomyia. Leishmania major DNA was detected by PCR in 7 of the 446 females (1.6%), specifically 2 out of 115 Phlebotomus duboscqi specimens, and 5 from 198 Sergentomyia darlingi specimens. Human DNA was detected in one blood-fed female S. darlingi positive for L. major DNA. Conclusion: Our data suggest the possible involvement of P. duboscqi and potentially S. darlingi in the transmission of ZCL in Mali

    Can oral corticosteroids reduce the severity or duration of an acute cough, and the associated National Health Service and societal costs, in adults presenting to primary care?: study protocol for a randomised controlled trial

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    Background: Acute lower respiratory tract infection (LRTI) is one of the most common conditions managed internationally and is costly to health services and patients. Despite good evidence that antibiotics are not effective for improving the symptoms of uncomplicated LRTI, they are widely prescribed, contributing to antimicrobial resistance. Many of the symptoms observed in LRTI are mediated by inflammatory processes also observed in exacerbations of asthma, for which there is strong evidence of corticosteroid effectiveness. The primary aim of the OSAC (Oral Steroids for Acute Cough) Trial is to determine whether oral prednisolone (40 mg daily for 5 days) can reduce the duration of moderately bad (or worse) cough and the severity of all its associated symptoms on days 2 to 4 post-randomisation (day 1 is trial entry) by at least 20% in adults ≥18 years with acute LRTI presenting to primary care. Methods/design: OSAC is a two-arm, multi-centre, placebo-controlled, randomised superiority trial. The target sample size is 436 patients, which allows for a 20% dropout rate. Patients will be recruited from primary care sites (General Practitioner surgeries) across England and followed up until symptom resolution. The two primary clinical outcomes are the duration of moderately bad (or worse) cough, and the severity of all its associated symptoms on days 2 to 4 post-randomisation. Secondary outcomes include: antibiotic consumption; symptom burden; adverse events; participant satisfaction with treatment and intention to consult for future similar illnesses. A parallel economic evaluation will investigate the cost-effectiveness of the intervention. Discussion: Results from the OSAC trial will increase knowledge regarding the clinical and cost-effectiveness of corticosteroids for LRTI, and will establish the potential of a new treatment option that could substantially improve patient health. We have chosen a relatively high ‘efficacy dose’ as this will enable us to decide on the potential for further research into lower dose oral and/or inhaled corticosteroids. This trial will also contribute to a growing body of research investigating the natural course of this very common illness, as well as the effects of steroids on the undesirable inflammatory symptoms associated with infection. Trial registration: Current Controlled Trials ISRCTN57309858 (31 January 2013)

    First Molecular Epidemiological Study of Cutaneous Leishmaniasis in Libya

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    Cutaneous leishmaniasis (CL) is caused by protozoan parasites of the genus Leishmania. The disease is characterized by the formation of chronic skin lesions followed by permanent scars and deformation of the infected area. It is distributed in many tropical and subtropical countries with more than 2 million cases every year. During the past few years CL has emerged as a major public health problem in Libya. So far, diagnosis was based on clinical symptoms and microscopic observation of parasites. Disease outbreaks were not investigated and the causative leishmanial species of CL were not identified so far. Our study indicates the presence of two coexisting species: Leishmania major and Leishmania tropica. These results are crucial in order to provide accurate treatment, precise prognosis and appropriate public health control measures. The recent armed conflict in Libya that ended with the Gadhafi regime collapse on October 2011 has affected all aspects of the life in the country. In this study we discussed multiple risk factors that could be associated with this conflict and present major challenges that should be considered by local and national health authorities for evaluating the CL burden and highlighting priority actions for disease control

    Seasonality and Prevalence of Leishmania major Infection in Phlebotomus duboscqi Neveu-Lemaire from Two Neighboring Villages in Central Mali

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    Phlebotomus duboscqi is the principle vector of Leishmania major, the causative agent of cutaneous leishmaniasis (CL), in West Africa and is the suspected vector in Mali. Although found throughout the country the seasonality and infection prevalence of P. duboscqi has not been established in Mali. We conducted a three year study in two neighboring villages, Kemena and Sougoula, in Central Mali, an area with a leishmanin skin test positivity of up to 45%. During the first year, we evaluated the overall diversity of sand flies. Of 18,595 flies collected, 12,952 (69%) belonged to 12 species of Sergentomyia and 5,643 (31%) to two species of the genus Phlebotomus, P. duboscqi and P. rodhaini. Of those, P. duboscqi was the most abundant, representing 99% of the collected Phlebotomus species. P. duboscqi was the primary sand fly collected inside dwellings, mostly by resting site collection. The seasonality and infection prevalence of P. duboscqi was monitored over two consecutive years. P. dubsocqi were collected throughout the year. Using a quasi-Poisson model we observed a significant annual (year 1 to year 2), seasonal (monthly) and village effect (Kemena versus Sougoula) on the number of collected P. duboscqi. The significant seasonal effect of the quasi-Poisson model reflects two seasonal collection peaks in May-July and October-November. The infection status of pooled P. duboscqi females was determined by PCR. The infection prevalence of pooled females, estimated using the maximum likelihood estimate of prevalence, was 2.7% in Kemena and Sougoula. Based on the PCR product size, L. major was identified as the only species found in flies from the two villages. This was confirmed by sequence alignment of a subset of PCR products from infected flies to known Leishmania species, incriminating P. duboscqi as the vector of CL in Mali
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