Rapid exploration with multi-rotors: A frontier selection method for high speed flight

Exploring and mapping previously unknown environments while avoiding collisions with obstacles is a fundamental task for autonomous robots. In scenarios where this needs to be done rapidly, multi-rotors are a good choice for the task, as they can cover ground at potentially very high velocities. Flying at high velocities, however, implies the ability to rapidly plan trajectories and to react to new information quickly. In this paper, we propose an extension to classical frontier -based exploration that facilitates exploration at high speeds. The extension consists of a reactive mode in which the multi-rotor rapidly selects a goal frontier from its field of view. The goal frontier is selected in a way that minimizes the change in velocity necessary to reach it. While this approach can increase the total path length, it significantly reduces the exploration time, since the multi-rotor can fly at consistently higher speeds

Quantitation of viral RNA levels of H5N1 RNP complexes containing PB2 mutations.

<p>293T cells were co-transfected with expression plasmids of NP, PA, PB1 and either wild type (WT) of indicated PB2 mutants with amino acid substitution of E158G, T271A or E627K, together with pPolI-NA plasmid. Total cellular RNA was isolated after 48 hours post-transfection and subjected to quantitative RT-PCR for segment 6 (NA genes) transcripts. Cells were incubated at (A) 33°C, (B) 37°C. RNA levels were expressed as relative activity to wild-type. Results shown are means with standard deviations from three independent assays. *indicates <i>P</i><0.05 when compared to wild-type.</p

Comparison of <i>in vitro</i> polymerase activity of reconstituted RNP complexes.

<p>Activities of polymerase complexes with a single gene replacement following expression in human 293T cells. (A) H5N1 polymerase complexes substituted with one H3N2 gene, (B) H3N2 polymerase complexes substituted with one H5N1 gene, (C) H5N1 polymerase complexes substituted with one H1N1pdm09 gene, and (D) H1N1pdm09 polymerase complexes substituted with one H5N1 gene, were analyzed in 293T cells transfected with the indicated plasmids of NP, PA, PB1 and PB2 together with pPolI-vNP-Luc and a reporter plasmid pGL4.73. Cells were incubated at 33°C and 37°C. Polymerase activity was normalized with the expression of a reporter plasmid. Relative polymerase activity (%) was expressed as relative activity to the corresponding parental vRNPs. Results shown are means with standard deviations from three independent assays.</p

Comparison of <i>in vitro</i> polymerase activity of H1N1pdm09, seasonal H3N2, avian H5N1, and WSN H1N1.

<p>293T cells were co-transfected with expression plasmids of NP, PA, PB1 and PB2 together with pPolI-vNP-Luc and a reporter plasmid pGL4.73 [hRluc/SV40], encoding a <i>Renilla</i> luciferase gene. Cells were incubated at (A) 33^o and (B) 37°C. Polymerase activity was normalized with the expression of a reporter plasmid. Relative polymerase activity (%) was expressed as relative activity to WSN H1N1 in percentage. Results shown are means with standard deviations from three independent assays. *indicates <i>P</i><0.05 when compared to WSN H1N1, and ***indicates <i>P</i><0.001 when compared to H5N1.</p

Polymerase activity of H5N1 RNP complexes containing mutations E158G, T271A and E627K in PB2.

<p>293T cells were co-transfected with expression plasmids of NP, PA, PB1 and either wild type (WT) or PB2 mutants with the indicated amino acid substitution of E158G, T271A or E627K, together with pPolI-vNP-Luc and a reporter plasmid pGL4.73. Cells were incubated at (A) 33°C, (B) 37°C. Polymerase activity was normalized with the expression of a reporter plasmid. Relative polymerase activity (%) was expressed as relative activity to WT. Results shown are means with standard deviations from three independent assays. *indicates <i>P</i><0.05 when compared to WT.</p

Bayesian Coalescent Analysis for Hepatitis C Virus 6a.

<p>Evolutionary rates are represented in a unit of substitution/site/year. MRCA: most recent common ancestor.</p

Evolutionary Relationship of Hepatitis C Virus 6a Isolates.

<p>HCV sequences were denoted in the format “subgenotype.country.strain. GenBank accession number”. VN: Vietnam, HK: Hong Kong, US: United States. “Outgroup” was labeled for 1a outgroup strain HCV-H. Ellipse “A” encloses those Vietnamese HCV 6a strains (except 6a.HK.6a74) that are located more closely to the origin of evolution. Ellipse “B” encloses two Vietnamese strains that were located parallel to Hong Kong strains. “6a.HK.6ann” denoted samples that were sequenced in this study.</p

Endemic History of Hepatitis C Virus 6a in Hong Kong.

<p>Black line: increases in HCV 6a population estimated using BEAST. Carmine line: population of Vietnamese Boat People remaining in Hong Kong. Blue line: new arrival of Vietnamese to Hong Kong. X-axis: year. Y-axis: <i>left</i>: estimated HCV 6a population size, <i>right</i>: Vietnamese population. P1: first peak of Vietnamese Boat people arrival to Hong Kong (1979). P2: second peak of Vietnamese Boat people arrival to Hong Kong (1992). Exponential spread: estimated HCV 6a exponential increase period (1986–1994) by BEAST inference.</p

Uptake of human papillomavirus (HPV) vaccination in Hong Kong: Facilitators and barriers among adolescent girls and their parents

<div><p>The present study is aimed at assessing the feasibility of delivering the HPV (human papillomavirus) vaccine to girls through a school-based program in Hong Kong, as well as to examine the facilitators and barriers associated with their participation. We approached 1,229 eligible girls aged 9 to 14 at eight schools in Hong Kong to join the program and then delivered the bivalent HPV vaccine at 0 and 6 months over the course of one school year. The students and their parents completed separate questionnaires to indicate their decision on whether or not to participate, and to assess their knowledge of cervical cancer and the HPV vaccine. The overall vaccine uptake was 81.4% (1,000/1,229) for the first dose and 80.8% (993/1,229) for the second dose. Parents and students were given separate questionnaires and asked whether or not they would like to participate in the vaccination program. 87.1% (1,010/1,160) of parents and 84.9% (974/1,147) of students indicated that they would join the program. The reasons associated with parents’ decision not to vaccinate their daughters primarily included concerns around side effects and safety. Multivariate regression analysis showed that parents who thought that the vaccine would protect their daughter from getting cervical cancer (OR = 3.16, 95% CI = 1.39–7.15, <i>p</i> < .01), and those who reported having a doctor’s recommendation (OR = 4.54, 95% CI = 1.05–19.57, p < .05) were more likely to join the program. In contrast, parents who had never heard of the vaccine (OR = .15, 95% CI = .03–.71, <i>p</i> < .02), those who were willing to pay more than HK$2,000 for the vaccine (OR = .39, 95% CI = .19–.81, <i>p</i> < .05), or had a preference to access it through a private clinic (OR = .44, 95% CI = .26–.75, <i>p</i> < .01) were significantly less likely to allow their daughter to join the program. Delivery of the HPV vaccine with high uptake rate in a school setting is feasible in Hong Kong. Engaging key stakeholders including school administrators, teachers and community physicians, and providing relevant information on safety and vaccine effectiveness to parents were important to the success of the program.</p></div

The assoication between preferred vaccine (Cervarix® vs. Gardasil® vs. no preference) and the reasons to choose vaccines (A to N).

<p>(A: Stronger protection; B: Safety; C: Lower price; D: More HPV types; E: Protect against genital warts; F: Better antibody response; G: Long-lasting immunity; H: Cross-protection for other cancer-associated HPV types; I: Better adjuvant; J: Patients think it’s better; K: Practice management; L: Selected by the Government; M: Credibility of manufacturer; N: Comprehensive service of manufacturer). All comparisons among vaccine preference groups across reasons to choose vaccine categories (A to N) were statistically significant (p<0.05).</p