Analytical Approach for Optimal Deployment of Drone Base Stations in Cellular Networks

Reliable mobile communications is of critical importance, and should be maintained even in case of extremely crowded events or emergency scenarios. In such scenarios the deployment of drone-mounted base stations offers an agile and cost-efficient way to sustain coverage and/or provide capacity relief. In this paper we develop an analytical method to estimate the blocking and coverage probabilities of drone-assisted cellular networks using information that is readily available from network planning tools. We demonstrate how this method can be used to determine the minimum required number of drones and their corresponding locations for a given target performance level.</p

Dietary fibre and fatty acids in chronic obstructive pulmonary disease risk and progression: a systematic review.

Dietary intake attracts increasing interest in the risk for and chronic obstructive pulmonary disease (COPD). In particular, dietary fatty acids have drawn specific attention for their immunomodulating The study aimed to review the current evidence on the potential roles of fibre or fatty acid intake in the risk and progression of COPD. Pubmed, Cochrane Collaboration Database and conference databases for original adults addressing the association between fibre or fatty acid intake and terms of risk, lung function and respiratory symptoms were searched. articles were included of which four reported on dietary fibre and five acids. Data of studies could not be pooled because of methodological Greater intake of dietary fibre has been consistently associated with COPD risk, better lung function and reduced respiratory symptoms. associations between fatty acids and COPD are inconsistent. Dietary deserves further attention in developing COPD prevention and managemen

Online Positioning of a Drone-Mounted Base Station in Emergency Scenarios

Wireless communication networks provide a critical infrastructure, particularly in emergency situations due to disruptive events such as natural disasters or terrorist attacks. However, in these kinds of scenarios part of the network may no longer be operational and a traffic hotspot may emerge, which may result in coverage and/or capacity issues. Deploying self-steering drone-mounted base stations offers a potential method to quickly restore coverage and/or provide capacity relief in such situations, but appropriate positioning is crucial in order for a drone base station to be truly effective. Motivated by that challenge, we propose a data-driven algorithm to optimize the position of a drone base station in a scenario with a site failure and emergence of a traffic hotspot. We demonstrate that the use of a drone, when properly positioned, yields significant performance gains, and that our algorithm outperforms benchmark mechanisms in a wide range of scenarios. In addition, we show that our algorithm is able to find a near-optimal position for the drone in a reasonable amount of time, and even has the ability to track the optimal position in case of a moving hotspot

The isolation of plasmids containing DNA complementary to messenger RNA for variant surface glycoproteins of Trypanosoma brucei.

We have isolated poly(A)+ RNA from four antigenic variants (117, 118, 121, 221) of one clone of Trypanosoma brucei. Translation of these poly(A)+ RNAs in a rabbit reticulocyte lysate gave rise to proteins that could be precipitated with antisera against homologous variant surface glycoprotein, the protein responsible for antigenic variation in trypanosomes. From the electrophoretic mobility of these in vitro products in sodium dodecyl sulphate (SDS) gels we infer that variant surface glycoproteins (VSGs) are made as pre-proteins, which require trimming to yield mature VSGs. The total translation products from the four poly(A)+ RNAs produced a complex set of bands on SDS gels, which only differed in the region where the variant pre-glycoproteins migrated. The only detectable variation in the messenger RNA populations of these variants is, therefore, in the messenger RNA for variant pre-glycoproteins. We have made duplex DNA copies of these poly(A)+ RNAs, linked the complementary DNA to plasmid pBR322 by GC tailing and cloned this recombinant DNA in Escherichia coli. Colony hybridization with complementary DNA made on poly(A)+ RNA showed that 7--10% of the colonies contained DNA that hybridized only with the homologous probe. Plasmid DNA was isolated from ten such colonies (two or three of each variant complementary DNA), bound to diazobenzyloxymethyl-cellulose (DBM) paper and used to select complementary messenger RNA from total poly(A)+ RNA by hybridization. In eight cases the RNA recovered from the filter gave variant pre-glycoprotein as the predominant product of in vitro translation. Poly(A)+ RNA from each of the variants only hydridized to the homologous complementary DNA in filter hybridizations. Each trypanosome variant, therefore, contains no detectable messenger RNAs for the three heterologous variant-specific glycoproteins tested. We conclude from this lack of cross-hybridization that antigenic diversity in trypanosomes, unlike antibody diversity in mammals, does not involve the linkage of a repertoire of genes for the variable N-terminal half to a single gene for the C-termina

Muscle Quality is More Impaired in Sarcopenic Patients With Chronic Obstructive Pulmonary Disease

BACKGROUND: Quadriceps muscle fiber atrophy and a loss of oxidative type I muscle fibers and mitochondrial content often occur in chronic obstructive pulmonary disease (COPD), which adversely affects exercise performance. Sarcopenia is an age-related syndrome characterized by wasting and weakness of muscle mass. We recently showed in a large cohort of patients that COPD-related sarcopenia, in particular in male patients, was not only associated with impaired quadriceps muscle strength but also with decreased exercise performance endurance, which could imply involvement of altered muscle fiber type composition. Hence, we hypothesized that both the fiber atrophy and loss of oxidative muscle fibers are more pronounced in sarcopenic compared with nonsarcopenic patients with COPD. OBJECTIVE: The objective of this study was to investigate quadriceps muscle fiber-type characteristics in relation to presence of sarcopenia in patients with COPD and in healthy age-matched controls. DESIGN: For this retrospective cross-sectional study, body composition (assessed by dual-energy x-ray absorptiometry) and quadriceps muscle biopsy (fiber type distribution and sizes) data were collected from 45 patients with COPDs (aged 42-77 years) and 52 healthy controls (aged 50-77 years). Sarcopenia was based on assessment of appendicular skeletal muscle mass index. RESULTS: Sarcopenia was found in 5.8% of healthy controls and in 31.1% of patients with COPD (P < .01). The proportion of oxidative type I fibers and size of type IIx muscle fibers were decreased in patients with COPD, and the sarcopenic subgroup showed a further decreased proportion as well as a lower size of type I fibers. CONCLUSIONS: Type I muscle fiber proportion is lower in sarcopenic compared with nonsarcopenic patients with COPD. Longitudinal studies may elucidate if the loss of muscle oxidative phenotype drives or accelerates the process of muscle wasting

Sodium salicylate improves detection of amplitude-modulated sound in mice

Salicylate is commonly used to induce tinnitus in animals, but its underlying mechanism of action is still debated. We therefore tested its effects on the firing properties of neurons in the mouse inferior colliculus (IC). Salicylate induced a large decrease in the spontaneous activity and an increase of ∼20 dB SPL in the minimum threshold of single units. In response to sinusoidally modulated noise (SAM noise) single units showed both an increase in phase locking and improved rate coding. Mice also became better at detecting amplitude modulations, and a simple threshold model based on the IC population response could reproduce this improvement. The responses to dynamic random chords (DRCs) suggested that the improved AM encoding was due to a linearization of the cochlear output, resulting in larger contrasts during SAM noise. These effects of salicylate are not consistent with the presence of tinnitus, but should be taken into account when studying hyperacusis.</p