5,816 research outputs found

    A Chemistry-Inspired Framework for Achieving Consensus in Wireless Sensor Networks

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    The aim of this paper is to show how simple interaction mechanisms, inspired by chemical systems, can provide the basic tools to design and analyze a mathematical model for achieving consensus in wireless sensor networks, characterized by balanced directed graphs. The convergence and stability of the model are first proven by using new mathematical tools, which are borrowed directly from chemical theory, and then validated by means of simulation results, for different network topologies and number of sensors. The underlying chemical theory is also used to derive simple interaction rules that may account for practical issues, such as the estimation of the number of neighbors and the robustness against perturbations. Finally, the proposed chemical solution is validated under real-world conditions by means of a four-node hardware implementation where the exchange of information among nodes takes place in a distributed manner (with no need for any admission control and synchronism procedure), simply relying on the transmission of a pulse whose rate is proportional to the state of each sensor.Comment: 12 pages, 10 figures, submitted to IEEE Sensors Journa

    Numerical simulations of mountain winds in an alpine valley

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    The meteorological model WRF is used to investigate the wind circulation in Valle Camonica, Italy, an alpine valley that includes a large subalpine lake. The aim was to obtain the information necessary to evaluate the wind potential of this area and, from a methodological point of view, to suggest how numerical modeling can be used to locate the most interesting spots for wind exploitation. Two simulations are carried out in order to analyze typical scenarios occurring in the valley. In the first one, the diurnal cycle of thermally-induced winds generated by the heating-cooling of the mountain range encircling the valley is analyzed. The results show that the mountain slopes strongly affect the low-level winds during both daytime and nighttime, and that the correct setting of the lake temperature improves the quality of the meteorological fields provided by WRF significantly. The second simulation deals with an event of strong downslope winds caused by the passage of a cold front. Comparisons between simulated and measured wind speed, direction and air temperature are also shown

    D-mannose: a promising support for acute urinary tract infections in women. A pilot study

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    Urinary tract infections still represent a significant bother for women and result in high costs to the health system. D-mannose is a simple sugar; it seems able to hinder bacteria adhesion to the urothelium. The present study aimed to determine whether D-mannose alone is effective in treating acute urinary tract infections in women and its possible utility in the management of recurrences

    Characterization of DNA methylation as a function of biological complexity via dinucleotide inter-distances

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    We perform a statistical study of the distances between successive occurrencies of a given dinucleotide in the DNA sequence for a number of organisms of different complexity. Our analysis highlights peculiar features of the dinucleotide CG distribution in mammalian DNA, pointing towards a connection with the role of such dinucleotide in DNA methylation. While the CG distributions of mammals exhibit exponential tails with comparable parameters, the picture for the other organisms studied (e.g., fish, insects, bacteria and viruses) is more heterogeneous, possibly because in these organisms DNA methylation has different functional roles. Our analysis suggests that the distribution of the distances between dinucleotides CG provides useful insights in characterizing and classifying organisms in terms of methylation functionalities.Comment: 13 pages, 5 figures. To be published in the Philosophical Transactions A theme issue "DNA as information

    Oncoplastic central quadrantectomies

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    Tumors localized in the central quadrant (centrally located breast tumors) have always represented a challenge for the surgeon because of the critical aesthetical matters related to the nipple-areola complex (NAC). Many years of experience with breast cancer patients treated by using various oncoplastic techniques, has allowed us to develop the modified hemibatwing for the treatment of central breast tumors, where the NAC is involved. Modified hemibatwing-along with the removal of the NAC-is a useful oncoplastic technique and it represents an ideal option for the treatment of central tumors because it assures oncological safety, a reduced surgical timetable and greater aesthetical results

    The vanishing clone: karyotypic evidence for extensive intraclonal genetic variation in the peach potato aphid, Myzus persicae (Hemiptera:Aphididae)

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    Analysis of holocentric mitotic metaphase chromosomes of the peach-potato aphid Myzus persicae (Sulzer) clone 33H revealed different chromosome numbers, ranging from 12 to 17 within each embryo, in contrast to the standard karyotype of this species (2n=12). Chromosome length measurements revealed that the observed chromosomal mosaicism is due to recurrent fragmentations of chromosomes X, 1 and 3 due to fragile sites or to hot spots of recombination. Fluorescent in situ hybridization experiments showed that X chromosomes were frequently involved in recurrent fragmentations, in particular their telomeric end opposite to the nucleolar organizer region (NORs). Experiments to induce males showed that M. persicae clone 33H is obligately parthenogenetic. The reproduction by apomictic parthenogenesis, together with a high telomerase expression that stabilized the chromosomes involved in the fragmentations observed in the M. persicae clone 33H, appears to favour the stabilization of the observed chromosome instability

    Weekly versus three weeks chemotherapy for advanced ovarian cancer. A meta-analysis

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    Aim: Three weeks paclitaxel and carboplatin has been considered the standard of care for primary treatment of ovarian cancer (OC). Whether weekly therapy will further improve the clinical outcomes or not is still unclear. We conducted a meta-analysis to compare the two regimens. Method: Articles were selected with a systematic approach, using PubMed databases. Trials concerning comparison between carboplatin plus weekly paclitaxel (dose-dense regimen) and carboplatin plus paclitaxel every 3 weeks were considered. Outcomes included overall survival (OS), progression free survival (PFS) and severe acute toxicity. Results: Dose-dense regimen was associated with significant improvement of PFS compared with standard schedule, with HR of 0.73 (95% CI 0.61-0.88, p = 0.001). There was no difference in OS between treatment regimens (HR 0.95, 95% CI 0.77-1.16, p=0.06), as well as in term of severe acute toxicity. Conclusion: Dose-dense regimen is superior to standard schedule in terms of PFS. Further studies are necessary to firmly confirm this evidence in advanced OC treatment

    Survival nomograms after curative neoadjuvant chemotherapy and radical surgery for stage IB2-IIIB cervical cancer

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    PURPOSE: The purpose of this study was to develop nomograms for predicting the probability of overall survival (OS) and progression-free survival (PFS) in locally advanced cervical cancer treated with neoadjuvant chemotherapy and radical surgery. MATERIALS AND METHODS: Nomograms to predict the 5-year OS rates and the 2-year PFS rates were constructed. Calibration plots were constructed, and concordance indices were calculated. Evaluated variableswere body mass index, age, tumor size, tumor histology, grading, lymphovascular space invasion, positive parametria, and positive lymph nodes. RESULTS: In total 245 patients with locally advanced cervical cancer who underwent neoadjuvant chemotherapy and radical surgery were included for the construction of the nomogram. The 5-year OS and PFS were 72.6% and 66%, respectively. Tumor size, grading, and parametria status affected the rate of OS, whereas tumor size and positive parametria were the main independent PFS prognostic factors. CONCLUSION: We constructed a nomogram based on clinicopathological features in order to predict 2-year PFS and 5-year OS in locally advanced cervical cancer primarily treated with neoadjuvant chemotherapy followed by radical surgery. This tool might be particularly helpful for assisting in the follow-up of cervical cancer patients who have not undergone concurrent chemoradiotherapy
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