Temporary Unavailability Research Articles

Nonlinear Orbit Acquisition and Maintenance of a Lunar Navigation Constellation Using Low-Thrust Propulsion

In this research, a feedback nonlinear control law was designed and tested to perform acquisition and station-keeping maneuvers for a lunar navigation constellation. Each satellite flies an Elliptical Lunar Frozen Orbit (ELFO) and is equipped with a steerable and throttleable low-thrust propulsion system. Lyapunov stability theory was employed to design a real-time feedback control law, capable of tracking all orbital elements (including the true anomaly), expressed in terms of modified equinoctial elements (MEEs). Unlike previous research, control synthesis was developed in the complete nonlinear dynamical model, and allows for driving the spacecraft toward a time-varying desired state, which includes correct phasing. Orbit propagation was performed in a high-fidelity framework, which incorporated several relevant harmonics of the selenopotential, as well as third-body effects due to the gravitational pull of the Earth and Sun. The control strategy at hand was successfully tested through two Monte Carlo campaigns in the presence of nonnominal flight conditions related to estimation errors of orbit perturbations, accompanied by the temporary unavailability and misalignment of the propulsive thrust.

A lexicographic optimization-based approach for efficient task allocation in industrial transportation multi-robot systems

In industrial transportation applications, multi-robot systems (MRS) are assigned to perform transportation tasks until their batteries are depleted, requiring them to move to battery charging stations. This temporary unavailability of the robots during charging decreases system productivity that measures the number of transportation tasks accomplished with the available robot energy. As a result, maximizing task completion becomes crucial, especially with prioritized tasks and increased workload. This can be achieved through an energy management strategy. In this context, the Lexicographic Optimization-based Multi-Robot Task Allocation (LO-MRTA) approach is proposed to maximize the reward in terms of system productivity with a limited energy consumption. The existing multi-robot energy management approaches consider the energy management during the tasks execution and neglect workload scaling issue with increasing tasks, whereas the LO-MRTA approach accounts for the energy consumption in the large-scale tasks allocation process. The main idea of the proposed approach is to consider the global state of the robots in the MRS system before carrying out the tasks execution, enhancing the task allocation decisions in terms of the energy management. The evaluation scenarios show the promising performance of the LO-MRTA approach in comparison with three existing baselines in terms of the system productivity, overall energy consumption and workload scaling effects.

Optimizing pre-copy live virtual machine migration in cloud computing using machine learning-based prediction model

One of the preconditions for efficient cloud computing services is the continuous availability of services to clients. However, there are various reasons for temporary service unavailability due to routine maintenance, load balancing, cyber-attacks, power management, fault tolerance, emergency incident response, and resource usage. Live Virtual Machine Migration (LVM) is an option to address service unavailability by moving virtual machines between hosts without disrupting running services. Pre-copy memory migration is a common LVM approach used in cloud systems, but it faces challenges due to the high rate of frequently updated memory pages known as dirty pages. Transferring these dirty pages during pre-copy migration prolongs the overall migration time. If there are large numbers of remaining memory pages after a predefined iteration of page transfer, the stop-and-copy phase is initiated, which significantly increases downtime and negatively impacts service availability. To mitigate this issue, we introduce a prediction-based approach that optimizes the migration process by dynamically halting the iteration phase when the predicted downtime falls below a predefined threshold. Our proposed machine learning method was rigorously evaluated through experiments conducted on a dedicated testbed using KVM/QEMU technology, involving different VM sizes and memory-intensive workloads. A comparative analysis against proposed pre-copy methods and default migration approach reveals a remarkable improvement, with an average 64.91% reduction in downtime for different RAM configurations in high-write-intensive workloads, along with an average reduction in total migration time of approximately 85.81%. These findings underscore the practical advantages of our method in reducing service disruptions during live virtual machine migration in cloud systems.

Optimization, guidance, and control of low-thrust transfers from the Lunar Gateway to low lunar orbit

The Lunar Gateway will represent a primary space system useful for the Artemis program, Earth–Moon transportation, and deep space exploration. It is expected to serve as a staging location and logistic outpost on the way to the lunar surface. This study focuses on low-thrust transfer dynamics, from the Near-Rectilinear Halo Orbit traveled by Gateway to a specified Low-altitude Lunar Orbit (LLO). More specifically, this research addresses two closely-related problems: (i) determination of the minimum-time low-thrust trajectory and (ii) design, implementation, and testing of a guidance and control architecture, for a space vehicle that travels from Gateway to LLO. Orbit dynamics is described in terms of modified equinoctial elements, with the inclusion of all the relevant perturbations, in the context of a high-fidelity multibody ephemeris model. The minimum-time trajectory from Gateway to a specified lunar orbit is detected through an indirect heuristic approach, which uses the analytical conditions arising in optimal control theory in conjunction with a heuristic technique. However, future missions will pursue a growing level of autonomy, and this circumstance implies the mandatory design and implementation of an efficient feedback guidance scheme, capable of compensating for nonnominal flight conditions. This research proposes nonlinear orbit control as a viable and effective option for autonomous explicit guidance of low-thrust transfers from Gateway to LLO. This approach allows defining a feedback law that enjoys quasi-global stability properties without requiring any offline reference trajectory. The overall spacecraft dynamics is modeled and simulated, including attitude control and actuation. The latter is demanded to an array of reaction wheels, arranged in a pyramidal configuration. Guidance, attitude control, and actuation are implemented in an iterative scheme. Monte Carlo simulations demonstrate that the guidance and control architecture at hand is effective in nonnominal flight conditions, i.e. with random starting point from Gateway as well as in case of temporary unavailability of the propulsion system. The numerical results also point out that only a modest propellant penalty is associated with the use of feedback guidance and control in comparison to the minimum-time optimal trajectory.

Vaccination coverage and adverse events following a reactive vaccination campaign against hepatitis E in Bentiu displaced persons camp, South Sudan.

Hepatitis E (HEV) genotypes 1 and 2 are the common cause of jaundice and acute viral hepatitis that can cause large-scale outbreaks. HEV infection is associated with adverse fetal outcomes and case fatality risks up to 31% among pregnant women. An efficacious three-dose recombinant vaccine (Hecolin) has been licensed in China since 2011 but until 2022, had not been used for outbreak response despite a 2015 WHO recommendation. The first ever mass vaccination campaign against hepatitis E in response to an outbreak was implemented in 2022 in Bentiu internally displaced persons camp in South Sudan targeting 27,000 residents 16-40 years old, including pregnant women. We conducted a vaccination coverage survey using simple random sampling from a sampling frame of all camp shelters following the third round of vaccination. For survey participants vaccinated in the third round in October, we asked about the onset of symptoms experienced within 72 hours of vaccination. During each of the three vaccination rounds, passive surveillance of adverse events following immunisation (AEFI) was put in place at vaccination sites and health facilities in Bentiu IDP camp. We surveyed 1,599 individuals and found that self-reported coverage with one or more dose was 86% (95% CI 84-88%), 73% (95% CI 70-75%) with two or more doses and 58% (95% CI 55-61%) with three doses. Vaccination coverage did not differ significantly by sex or age group. We found no significant difference in coverage of at least one dose between pregnant and non-pregnant women, although coverage of at least two and three doses was 8 and 14 percentage points lower in pregnant women. The most common reasons for non-vaccination were temporary absence or unavailability, reported by 60% of unvaccinated people. Passive AEFI surveillance captured few mild AEFI, and through the survey we found that 91 (7.6%) of the 1,195 individuals reporting to have been vaccinated in October 2022 reported new symptoms starting within 72 hours after vaccination, most commonly fever, headache or fatigue. We found a high coverage of at least one dose of the Hecolin vaccine following three rounds of vaccination, and no severe AEFI. The vaccine was well accepted and well tolerated in the Bentiu IDP camp community and should be considered for use in future outbreak response.

ЛЕОНИД БРЕЖНЕВТІҢ ДЕНСАУЛЫҒЫ МЕМЛЕКЕТТІК МЕХАНИЗМНІҢ ЭЛЕМЕНТІ РЕТІНДЕ

The article analyzes the role of health status of Leonid Brezhnev, General Secretary of the Central Committee of Communist Party of the Soviet Union and the Chairmen of the Presidium of the Supreme Soviet of the USSR, as a major element of the state apparatus in the USSR. Using numerous sources, including notes and diaries of Brezhnev himself, notes of Brezhnev’s secretaries, memories of Brezhnev’s political companions, doctors and family members, the authors have reconstructed the dynamic changes in the health status of Brezhnev, and in which way these changes have impacted his work efficiency. Despite the fact that Brezhnev came to power already burdened by diseases and bad habits, his first decade as a leader of Soviet Union was very fruitful. This conclusion contradicts an established historiographical opinion that Brezhnev belonged to a type of a quite healthy, but lazy leader, who could not and did not like to perform the duties of the state and party leader, trying to evade them at every opportunity. The last seven years of Brezhnev’s rule are characterized by a sharp deterioration in health status that led to the alternating periods of decline and rise of Brezhnev’s work efficiency, which severely affected entire state apparatus. Despite the efforts of Brezhnev himself and the fact that Soviet bureaucracy managed to mostly compensate the periods of “stalling” and even the temporary unavailability of the leader, the USSR’s specific power mechanism started to malfunction during the second half of 1970s. Another consequence of Brezhnev’s decreased performance was the delegation of significant political power to the group of companions, led by Yuri Andropov and Konstantin Chernenko. Having occupied the post of head of state almost for life, being the leader of socio-political system, which actually did not have mechanism for a legal change of power, except for the death of a predecessor, sick and decrepit Brezhnev had to work hard and remain “a leader” until his death, including at the cost of drug addiction.

Models and algorithms for the preventive maintenance optimization of railway vehicles

The motivation of this paper follows strictly from industrial needs to improve competitiveness in railway companies by the efficient rolling stock utilization affected by the obligatory preventive maintenances of vehicles, which cause their temporary unavailability. Nevertheless, it is economically essential to minimize the total time on maintenances of vehicles, which can be achieved in a certain range by the scheduling of transport tasks taking into account maintenance policies of the vehicles, their mileage and date since the last maintenance, and the workload related to the tasks. Therefore, to face the problem, we model the consider issue as the job scheduling problem to maximize the availability of railway vehicles under preventive maintenances. We prove that the problem is strongly NP-hard and we propose efficient heuristic and metaheuristic algorithms that are characterized by a low computational complexity and they are able to find solutions satisfying from the perspective of industrial practice. The simulations based on real-life data reveal that our approach can provide schedules, which significantly improve availability of locomotives resulting in high potential financial benefits for railway companies.

Low-Thrust Transfer to Quasi-Synchronous Martian Elliptic Orbit via Nonlinear Feedback Control

This study considers the problem of injecting a spacecraft into an elliptic, repeating-ground-track orbit about Mars, starting from a 4-sol highly elliptical orbit, which is a typical Martian capture orbit, entered at the end of the interplanetary transfer. The final operational orbit has apoares corresponding to the maximum (or minimum) latitude, and nine nodal periods are flown in 5 Martian nodal days. The orbit at hand is proven to guarantee coverage properties similar to the Molniya orbit about Earth; therefore, it is especially suitable for satellites that form constellations. Low-thrust nonlinear orbit control is proposed as an affordable and effective option for orbit injection, capable of attaining significant propellant reduction if compared to alternative strategies based on chemical propulsion. This work introduces a new, saturated feedback law for the low-thrust direction and magnitude that is capable of driving the spacecraft of interest toward the operational orbit. Remarkable stability properties are proven to hold using the Lyapunov stability theory. Because no reference path is to be identified a priori, this technique represents a viable autonomous guidance strategy, even in the case of temporary unavailability of the low-thrust propulsion system or in the presence of widely dispersed initial conditions and errors on estimating orbit perturbations. Monte Carlo simulations prove that the feedback guidance strategy at hand is effective and accurate for injecting a spacecraft into the desired, repeating-ground-track operational orbit without requiring any reference transfer path.

Analisis Keamanan Infrastruktur Jaringan Berdasarkan Cyber Kill Chain Framework

This study concentrates on examining the security of network infrastructure using the cyber kill chain framework approach. The research is conducted within a company operating in network security services. In its operations, it offers a Virtual Private Cloud (VPC) containing various crucial information such as applications, internal data, client data, and product demos. Despite the attractive features of cloud computing, there are significant threats as well. Handling attacks cannot be swiftly and efficiently executed, resulting in temporary operational unavailability until the attacks are resolved. This research delves into the security of the company's infrastructure by testing several points of vulnerability exploited by malicious parties. The cyber kill chain framework approach is employed to systematically assess the company's infrastructure. The study reveals that certain issues have been adequately detected; however, security gaps persist, as evidenced by the testing conducted and the inadequate response from the company's security systems.

Memory sharing for handling memory overload on physical machines in cloud data centers

Over-committing computing resources is a widely adopted strategy for increased cluster utilization in Infrastructure as a Service (IaaS) cloud data centers. A potential consequence of over-committing computing resources is memory overload of physical machines (PMs). Memory overload occurs if memory usage exceeds a defined alarm threshold, exposing running computation tasks at a risk of being terminated by the operating system. A prevailing measure to handle memory overload of a PM is live migration of virtual machines (VMs). However, this not only consumes network bandwidth, CPU, and other resources, but also compels a temporary unavailability of the VMs being migrated. To handle memory overload, we present a memory sharing system in this paper for PMs in cloud data centers. With memory sharing, a PM automatically borrows memory from a remote PM when necessary, and releases the borrowed memory when memory overload disappears. This is implemented through swapping inactive memory pages to remote memory resource. Experimental studies conducted on InfiniBand-networked PMs show that the memory sharing system is fully functional. The measured throughput and latency are around 929 Mbps and 1.3 mus, respectively, on average for remote memory access. They are similar to those from accessing a local-volatile memory express solid-state drive, and thus are promising in real applications.

Routine Lupus Anticoagulant Sensitive aPTT Testing Can Prevent Unnecessary LA Testing.

Even though routine screening of the general hospital population is discouraged, medical laboratories may use a "lupus sensitive" activated partial thromboplastin time test (aPTT) with phospholipid concentrations that are susceptible to inhibition by lupus anticoagulant (LA), to screen for the presence of LA. If deemed necessary, follow-up testing according to ISTH guidelines may be performed. However, LA testing is a laborious and time-consuming effort that is often not readily available due to a lack of automation and/or temporary unavailability of experienced staff. In contrast, the aPTT is a fully automated test that is available 24/7 in almost all medical laboratories and is easily interpreted with the use of reference ranges. In addition to clinical signs, the result of an LA sensitive aPTT may thus be used to lower the suspicion of the presence of LA and reduce costly follow-up testing. In this study, we show that a normal LA sensitive aPTT result may be safely used to refrain from LA testing in the absence of strong clinical suspicion.

Cabergoline treatment promotes myocardial recovery in peripartum cardiomyopathy.

Peripartum cardiomyopathy (PPCM) is a rare heart disease, occurring in previously heart-healthy women during the last month of pregnancy or the first months after delivery due to left ventricular (LV) systolic dysfunction. A common pathomechanistic pathway of PPCM includes increased oxidative stress and the subsequent generation of a cleaved prolactin fragment (16kDa PRL), which promotes the onset of heart failure (HF) in a microRNA (miR)-146a-dependent manner. Inhibition of prolactin secretion with the dopamine D2 receptor (D2R) agonist bromocriptine combined with standard HF therapy supports cardiac recovery. This study examined whether treatment with the more selective D2R agonist cabergoline prevents HF development in an experimental PPCM mouse model and might be used as an alternative treatment regime for PPCM. Postpartum (PP) female PPCM-prone mice with a cardiomyocyte restricted STAT3-deficiency (αMHC-Cretg/+ ; Stat3fl/fl ; CKO) were treated over two consecutive nursing periods with cabergoline (CKO Cab, 0.5mg/kg/day) and were compared with bromocriptine treated CKO (CKO Br) and postpartum-matched WT and CKO mice. Cabergoline treatment in CKO PP mice preserved cardiac function [fractional shortening (FS): CKO Cab: 34.5±9.4% vs. CKO: 22.1±9%, P<0.05] and prevented the development of cardiac hypertrophy, fibrosis, and inflammation as effective as bromocriptine therapy (FS: CKO Br: 33.4±5.6%). The myocardial up-regulation of the PPCM biomarkers plasminogen inhibitor activator 1 (PAI-1) and miR-146a were prevented by both cabergoline and bromocriptine therapy. A small cohort of three PPCM patients from the German PPCM Registry was treated with cabergoline (1mg per week for 2weeks, followed by 0.5mg per week for another 6weeks) due to a temporary unavailability of bromocriptine. All PPCM patients initially presented with a severely reduced LV ejection fraction (LVEF: 26±2%). However, at 6months of follow-up, LV function (LVEF: 56±2%) fully recovered in all three PPCM patients, and no adverse events were detected. In the experimental PPCM mouse model, the selective D2R agonist cabergoline prevents the onset of postpartum HF similar to bromocriptine. In PPCM patients, cabergoline treatment was safe and effective as all patients fully recovered. Cabergoline might serve as a promising alternative to bromocriptine. However, these findings are based on experimental data and a small case series and thus have to be interpreted with caution and should be validated in a larger clinical trial.

Buffer-Aided Relaying Strategies for Two-Way Wireless Networks

The energy and time efficiency of wireless sensor networks (WSNs) is frequently affected by the low reliability of their links. To mitigate the outage probability, cooperation topologies are used. However, these topologies have particular challenges since the relay consumes energy in assisting a foreign communication, and the successful transmission in each direction is conditioned to the availability of the two segments involved in the communication. To overcome the temporary unavailability of a link, the use of buffers in the relay has been proposed, but energy and time efficiency remain a challenge for basic configurations. We propose two-way buffer-aided relaying strategies that exploit the presence of buffers in the different nodes that participate in the communication, as well as the efficient use of buffer capacity. The proposed strategies make the decision to forward the messages in one of the communication directions or broadcast coded messages based on buffer and channel state information. Firstly, we evaluate the impact of considering the use of buffers in the transmitter nodes. Then, we propose and evaluate the impact of the full and joint use of the entire buffer capacity to assist communication in both directions. Finally, we evaluate the performance of a system that exploits both the use of full and joint buffering and the presence of buffering in the transmitter. The results show that better performance, in terms of outage probability, is obtained by the third strategy; since it allows the buffer capacity to be exploited to a greater extent in the most urgent direction at each moment, as well as to select the start of each transmission to a viable communication opportunity. This represents a notable benefit in terms of energy and time efficiency for WSNs since unnecessary transmission of information is avoided, the number of idle slots decreases, and the amount of information per unit of time and energy increases.

Defibrotide Protects Endothelium from Radiation Induced Injury: A Potential New Strategy in the Armamentarium against Radiation Toxicity

<h3>Purpose/Objective(s)</h3> Radiation induced toxicity (RIT) has long been a notorious limit of radiotherapy. RIT can only be circumvented by patient selection or dose de-escalation. No effective treatment of RIT is available. Endothelium injury (EnI) has been recognized as the key pathogenesis in radiotoxicity. EnI initiates the vicious cascade and propagates to various RIT. Defibrotide (DF), a mixture of oligonucleotides, is a potent endothelium protector and is the only medication approved for the treatment of post-HSCT severe hepatic sinusoid obstructive syndrome (SOS), with survival benefits and minimal toxicity. The protective effect of DF has been exhibited in chemo-toxicity, hypoxia, physical injury and infection, but not yet in radiation (RT). We hypothesize that DF alleviates RIT through a similar mechanism. Here, we present the first report and primitive results of an in vitro study of DF in RT setting. <h3>Materials/Methods</h3> Primary human hepatic sinusoidal endothelial cells (HHSEC) and human umbilical vein endothelial cells (HUVEC) were cultured and RT for a single 4Gy or 8Gy with or without DF at the final concentration of 300ug/ml. Assays for cell viability, survival and proliferation were evaluated. Molecule expression pattern was analyzed by rt-PCR. All the assays were replicated 3 times. <h3>Results</h3> After RT, HHSECs became sparse and deformed under the microscope. In contrast, HHSECs cultured with DF before RT generally appeared normal. In accordance, a cell counting kit assay showed that viability of HHSECs was preserved after RT at the presence of DF, while it was dramatically reduced by RT alone (p<0.001). Flow cytometry analysis of programed cell death 48h post-RT confirmed that DF significantly reduced both early and late apoptosis (8.9% vs 14.6%, p<0.05). In the proliferation assay, RT alone almost quartered the number of HUVEC clones, while DF co-treatment partially prevented the extermination. DF alone had no deleterious effect compared with control groups, in concordance with published studies. RT-PCR revealed elevated expression of pro-inflammatory and pro-coagulant molecules. In detail, raised mRNA levels of von Willebrand factor (vWF), ICAM-1, VCAM-1, IL-1a, IL-1b, IL-6, TNF-a and eNOS were detected after RT, which were down regulated by DF. DNA break assay by γ-H2AX formation was performed, which showed no drastic difference of γ-H2AX staining after RT with or without DF, implicating other mechanisms. Besides, DF prophylaxis before RT rather than salvage after RT revealed better endothelium protection. We then built a rat model of radiation induced endothelium injury (RIEI) by whole liver exposure. However, due to the COVID-19 outbreak and temporary un-availability of DF, further study is in waiting. <h3>Conclusion</h3> Effective therapy of RIT is a huge unmet medical need. DF, an approved, well-tolerated orphan drug for post-HSCT SOS, exhibited definitive protective effect in RIEI as well. Further studies, not only pre-clinically but also in clinical scenarios are warranted and in eager expectation.

Forbidden fruit or soured grapes? Long-term effects of the temporary unavailability and rationing of US news websites on their consumption from the European Union

In May 2018, hundreds of websites located outside the European Union (EU), including USAToday.com, became completely or partially unavailable to EU citizens as a number of publishers decided to comply with an EU data protection regulation (GDPR) by blocking access. Several of the sites that started to exclude EU users continued to do so for months or years, even though some of their competitors, like the New York Times, never adopted a policy of exclusion. These differing strategies allowed us to conduct a quasi-experimental study on the effects of temporary product unavailability and temporary rationing. We find that both temporary product withdrawal and temporary rationing can have long-term effects. In our case, monthly unique visitors in the months and even years after full access was restored were between 44% and 61% lower than they had been before the restrictions were imposed, with a wider market contraction explaining only part of these falls. We also find distinct differences between the effects of temporarily rationing and temporarily withdrawing websites. Although both strategies lead to a long-term loss in visitors, rationing appears to increase a website's desirability for some consumers. After rationing was lifted, USAToday.com's reduced audience consumed the title more deeply and frequently than had been the case before rationing was imposed.

КУРОРТНО-ОЗДОРОВЧІ ТЕРИТОРІЇ СХІДНИХ РЕГІОНІВ УКРАЇНИ ЯК ОСНОВА РОЗВИТКУ ЛІКУВАЛЬНОГО ТУРИЗМУ

The article deals with the possibility of developing health tourism on the basis of existing resort and recreational territories in eastern Ukraine. It is established that the eastern territories of Ukraine are considered exclusively as an industrial component of our state, so they have a low level of development of medical tourism. The resort and resource base of the eastern territories, which can be used for the development of health tourism in the region, is studied. The analysis of the current state of Sanatorium-resort enterprises in the region is carried out. The problems of development of health tourism in the region are identified, including: military instability, which causes a feeling of fear of tourists about travel; stereotypical information and ideas about the Donbass; inconsistency of pricing policy with the quality of services; neglect and low competitiveness of accommodation facilities; lack of information interaction with other regions of the country and advertising of resort enterprises in the tourism market. It is established that in the region there was a sharp decrease in the number of Sanatorium-resort institutions due to long-term instability and temporary unavailability of some Resort and recreational facilities. Possible ways to overcome the problems of developing medical tourism in the resort and recreational territories of the region are proposed. It is recommended to use more intensively the existing resort and recreational potential in the form of therapeutic mineral waters and therapeutic mud used in balneology, natural and climatic features, such as access to the sea, significant forest stands, steppe expanses. It is noted that a special feature of the region is the presence in Solidar of a unique speleosanatorium, which is located underground and specializes in the treatment of diseases of the respiratory system and thyroid gland. Treatment and recovery take place in special salt rooms. The territory of our state has a unique natural and recreational potential, and the population (both local and foreign) is becoming more and more interested in the services of Sanatorium-resort enterprises.

An Information-Theoretic Approach for Reliable Distributed Storage Systems

Nowadays exponential growth of the total amount of data stored by humanity leads to the expansion of distributed storage systems. Such systems have a huge amount of geographically distributed servers that give good scalability. The main challenges with such systems are the temporary unavailability of servers due to features of hardware inside them as well as confidentiality issues. In this paper we consider the information-theoretic approach to solve these issues and give possible further research direction in this area.

Alternative antimicrobials for prophylaxis of the Group B Streptococcus maternal-fetal disease.

GBS colonization is an important risk factor for maternal and neonatal infection morbidity and mortality. Intrapartum antibiotics may prevent vertical transmission of GBS from colonized mothers to their babies. The objective of this study was to evaluate the effectiveness of cefazolin prophylactic regimen for GBS disease, comparing it to the established penicillin-based protocols, given the opportunity provided by the temporary unavailability of first-choice antibiotics in Brazil. A retrospective analysis was conducted at the Hospital Femina Obstetrics Service between January and December 2015. Ninety-eight pregnant women received standard penicillin (70 patients) or ampicillin (28 patients) antibiotic prophylaxis, and 251 pregnant women received an alternative prophylaxis with cefazolin during the study period. Risk factor, Maternal and neonatal outcomes were evaluated and compared between groups. No significant difference was found in maternal (RR = 0.71; IC 95%:0.30-1.68; p = 0.709) and neonatal (RR = 0.84; IC 95%:0.61-1.15; p = 0.271) outcomes between those patients using the alternative antibiotic prophylaxis in comparison to the standard antibiotics, with the dependent variable of maternal and neonatal outcomes grouped and controlled for potential confounding variables. The antibiotics used as alternatives to penicillin and ampicillin for the prevention of maternal-fetal GBS disease are poorly studied, and this study indicate that cefazolin can be an optimal choice, offering safety in the use of this antibiotic in situations where penicillins are contraindicated or unavailable.

Basic principles of blind write protocol

The current approach to handle interleaved write operation and preserve consistency in relational database system still relies on the locking protocol. If any entity is locked by any transaction, then it becomes temporary unavailable to other transaction until the lock is released. The temporary unavailability can be more often if the number of write operation increases as happens in the application systems that utilize IoT technology or smartphone devices to collect the data. To solve this problem, this research is proposed blind write protocol which does not lock the entity while the transaction is performing a write operation. This paper presents the basic principles of blind write protocol implementation in a relational database system

Smart routing: Towards proactive fault handling of software-defined networks

In recent years, the emerging paradigm of software-defined networking has become a hot and thriving topic in both the industrial and academic sectors. Software-defined networking offers numerous benefits against legacy networking systems by simplifying the process of network management through reducing the cost of network configurations. Currently, data plane fault management is limited to two mechanisms: proactive and reactive. These fault management and recovery techniques are activated only after a failure occurrence and hence packet loss is highly likely to occur. This is due to convergence time where new network paths will need to be allocated in order to forward the affected traffic rather than drop it. Such convergence leads to temporary service disruption and unavailability. Practically, not only the speed of recovery mechanisms affects the convergence, but also the delay caused by the process of failure detection. In this paper, we define a new approach for data plane fault management in software-defined networks where the goal is to eliminate the convergence process altogether rather than accelerate the failure detection and recovery. We propose a new framework, called Smart Routing, which allows the network controller to receive forewarning signs on failures and hence avoid risky paths before the failure incidents occur. The proposed approach aims to decrease service disruption, which in turn increases network service availability. We validate our framework through a set of experiments that demonstrate how the underlying model runs and its impact on improving service availability. We take as example of the applicability of the new framework three types of topologies covering real and simulated networks.