17 research outputs found

    Five-year trends in epidemiology and prevention of mother-to-child HIV transmission, St. Petersburg, Russia: results from perinatal HIV surveillance

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    <p>Abstract</p> <p>Background</p> <p>The HIV epidemic in Russia has increasingly involved reproductive-aged women, which may increase perinatal HIV transmission.</p> <p>Methods</p> <p>Standard HIV case-reporting and enhanced perinatal HIV surveillance systems were used for prospective assessment of HIV-infected women giving birth in St. Petersburg, Russia, during 2004-2008. Trends in social, perinatal, and clinical factors influencing mother-to-child HIV transmission stratified by history of injection drug use, and rates of perinatal HIV transmission were assessed using two-sided χ<sup>2 </sup>or Cochran-Armitage tests.</p> <p>Results</p> <p>Among HIV-infected women who gave birth, the proportion of women who self-reported ever using injection drugs (IDUs) decreased from 62% in 2004 to 41% in 2008 (<it>P </it>< 0.0001). Programmatic improvements led to increased uptake of the following clinical services from 2004 to 2008 (all <it>P </it>< 0.01): initiation of antiretroviral prophylaxis at ≤28 weeks gestation (IDUs 44%-54%, non-IDUs 45%-72%), monitoring of immunologic (IDUs 48%-64%, non-IDUs 58%-80%) and virologic status (IDUs 8%-58%, non-IDUs 10%-75%), dual/triple antiretroviral prophylaxis (IDUs 9%-44%, non-IDUs 14%-59%). After initial increase from 5.3% (95% confidence interval [CI] 3.5%-7.8%) in 2004 to 8.5% (CI 6.1%-11.7%) in 2005 (<it>P </it>< 0.05), perinatal HIV transmission decreased to 5.3% (CI 3.4%-8.3%) in 2006, and 3.2% (CI 1.7%-5.8%) in 2007 (<it>P </it>for trend <0.05). However, the proportion of women without prenatal care and without HIV testing before labor and delivery remained unchanged.</p> <p>Conclusions</p> <p>Reduced proportion of IDUs and improved clinical services among HIV-infected women giving birth were accompanied by decreased perinatal HIV transmission, which can be further reduced by increasing outreach and HIV testing of women before and during pregnancy.</p

    Investigation of the motion parameters of technological complexes using a quaternion data fixation apparatus

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    Despite a fairly large range of methods known in the existing branches of technology and used in the industry for detecting possible failures and malfunctions, it is still relevant to study the possibilities of using modern digital tools and instruments that are capable of carrying out in-place diagnostics or fixing workers at a sufficient level of reliability with a minimum research time. Parameters of systems and elements of such a complex restored object as a technological complex used in agriculture. The article substantiates the use of a high-precision inclinometric complex for in-place diagnostics of a technological complex and presents the results of an experimental study of a machine-tractor unit

    IoT Security Mechanisms in the Example of BLE

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    In recent years, a lot of IoT devices, wireless sensors, and smart things contain information that must be transmitted to the server for further processing. Due to the distance between devices, battery power, and the possibility of sudden device failure, the network that connects the devices must be scalable, energy efficient, and flexible. Particular attention must be paid to the protection of the transmitted data. The Bluetooth mesh was chosen as such a network. This network is built on top of Bluetooth Low-Energy devices, which are widespread in the market and whose radio modules are available from several manufacturers. This paper presents an overview of security mechanisms for the Bluetooth mesh network. This network provides encryption at two layers: network and upper transport layers, which increases the level of data security. The network uses sequence numbers for each message to protect against replay attacks. The introduction of devices into the network is provided with an encryption key, and the out-of-band (OOB) mechanism is also supported. At the moment, a comparison has been made between attacks and defense mechanisms that overlap these attacks. The article also suggested ways to improve network resiliency

    IoT Security Mechanisms in the Example of BLE

    No full text
    In recent years, a lot of IoT devices, wireless sensors, and smart things contain information that must be transmitted to the server for further processing. Due to the distance between devices, battery power, and the possibility of sudden device failure, the network that connects the devices must be scalable, energy efficient, and flexible. Particular attention must be paid to the protection of the transmitted data. The Bluetooth mesh was chosen as such a network. This network is built on top of Bluetooth Low-Energy devices, which are widespread in the market and whose radio modules are available from several manufacturers. This paper presents an overview of security mechanisms for the Bluetooth mesh network. This network provides encryption at two layers: network and upper transport layers, which increases the level of data security. The network uses sequence numbers for each message to protect against replay attacks. The introduction of devices into the network is provided with an encryption key, and the out-of-band (OOB) mechanism is also supported. At the moment, a comparison has been made between attacks and defense mechanisms that overlap these attacks. The article also suggested ways to improve network resiliency

    The Influence of Oxygen Activity on Phase Composition, Crystal Structure, and Electrical Conductivity of CaV<sub>1–x</sub>Mo<sub>x</sub>O<sub>3±δ</sub>

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    Perovskite–like vanadate–molybdates are interesting from the point of view of their metal–like conductivity, which combines the correlated and free electron nature. A series of CaV1–xMoxO3–δ solid solutions was considered near the Mo concentration x = 0.4, where a difficult–to–perceive structural transition was previously detected. High-resolution transmission electron microscopy revealed the phase separation of CaV0.6Mo0.4O3–δ into nanoscale regions with different ratios of V and Mo concentrations, despite X–ray diffraction analysis exhibiting a homogeneous perovskite structure. The rest of the compositions from the CaV1–xMoxO3–δ series do not show phase separation. The nonmonotonic behavior of the conductivity and linear expansion of CaV1–xMoxO3±δ was shown when the oxygen activity in the N2-H2-H2O gas mixture was varied, which is mainly determined by the partial decomposition of the perovskite phase. Against this background, the behavior of the electrical properties of the CaV1–xMoxO3±δ individual phase remains unclear

    Designing a Tracked Running Gear of a Radio-Controlled Harvester

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    This work describes a model of a running gear of the designed tracked radio-controlled harvester intended for clean cutting which has been developed in the applied software package “Universal Mechanism” with use of the “Tracked Vehicles” module. It offers basic characteristics, justifies selection of variable parameters of the model. It describes modelling options of a model travel over variable irregularities, presents the obtained tractive effort torques on sprockets and loads acting on the support rollers

    Investigation of the suspension of vehicles moving on stone roads

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    The paper studies the problem of traffic on mountain roads of natural origin. A mathematical model of a natural stone road is presented, the paper demonstrates also diagrams of “floodplain surface vs. support bed slope” correlation function. The calculation of the ride comfort of vehicles utilizes a four-mass model. Calculation results are demonstrated for a GAZ-3308 truck, as well as for a vehicle with half the suspension rate. The result obtained shows 30-50% reduction of the vibration load at a suspension rate reduction by 50%, dependent on the road type. The travel speed can be increased by 45% dependent on the road type and driver’s work time

    Investigation of the suspension of vehicles moving on stone roads

    Get PDF
    The paper studies the problem of traffic on mountain roads of natural origin. A mathematical model of a natural stone road is presented, the paper demonstrates also diagrams of “floodplain surface vs. support bed slope” correlation function. The calculation of the ride comfort of vehicles utilizes a four-mass model. Calculation results are demonstrated for a GAZ-3308 truck, as well as for a vehicle with half the suspension rate. The result obtained shows 30-50% reduction of the vibration load at a suspension rate reduction by 50%, dependent on the road type. The travel speed can be increased by 45% dependent on the road type and driver’s work time
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