452 research outputs found
CDDT: Fast Approximate 2D Ray Casting for Accelerated Localization
Localization is an essential component for autonomous robots. A
well-established localization approach combines ray casting with a particle
filter, leading to a computationally expensive algorithm that is difficult to
run on resource-constrained mobile robots. We present a novel data structure
called the Compressed Directional Distance Transform for accelerating ray
casting in two dimensional occupancy grid maps. Our approach allows online map
updates, and near constant time ray casting performance for a fixed size map,
in contrast with other methods which exhibit poor worst case performance. Our
experimental results show that the proposed algorithm approximates the
performance characteristics of reading from a three dimensional lookup table of
ray cast solutions while requiring two orders of magnitude less memory and
precomputation. This results in a particle filter algorithm which can maintain
2500 particles with 61 ray casts per particle at 40Hz, using a single CPU
thread onboard a mobile robot.Comment: 8 pages, 14 figures, ICRA versio
Investigating the Role of the Annular Ligament in Zebrafish Cone Mosaic Formation and Maintenance
Honors (Bachelor's)NeuroscienceUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/112078/1/cfwalsh.pd
What is the state of children\u27s participation in qualitative research on health interventions?: A scoping study
BACKGROUND: Children are the focus of numerous health interventions throughout the world, yet the extent of children\u27s meaningful participation in research that informs the adaptation, implementation, and evaluation of health interventions is not known. We examine the type, extent, and meaningfulness of children\u27s participation in research in qualitative health intervention research.
METHOD: A scoping study was conducted of qualitative published research with children (ages 6-11âyears) carried out as part of health intervention research. Following Arksey and O\u27Malley\u27s scoping study methodology and aligned with the PRISMA-ScR guidelines on the reporting of scoping reviews, the authors searched, charted, collated, and summarized the data, and used descriptive and content analysis techniques. Ovid MEDLINE was searched from 1 January 2007 to 2 July 2018 using the keywords children, health intervention, participation, and qualitative research. Study selection and data extraction were carried out by two reviewers independently.
RESULTS: Of 14,799 articles screened, 114 met inclusion criteria and were included. The study identified trends in when children were engaged in research (e.g., post-implementation rather than pre-implementation), in topical (e.g., focus on lifestyle interventions to prevent adult disease) and geographical (e.g., high-income countries) focuses, and in qualitative methods used (e.g., focus group). While 78 studies demonstrated meaningful engagement of children according to our criteria, there were substantial reporting gaps and there was an emphasis on older age (rather than experience) as a marker of capability and expertise.
CONCLUSIONS: Despite evidence of children\u27s meaningful participation, topical, geographical, and methodological gaps were identified, as was the need to strengthen researchers\u27 skills in interpreting and representing children\u27s perspectives and experiences. Based on these findings, the authors present a summary reflective guide to support researchers toward more meaningful child participation in intervention research
Secreted metabolome of porcine blastocysts encapsulated with in \u3ci\u3ein vitro\u3c/i\u3e 3D alginate hydrogel culture systems under going morphological changes provides insights into specific mechanisms involved in the initiation of porcine conceptus elongation
Context. The exact mechanisms regulating the initiation of porcine conceptus elongation are not known due to the complexity of the uterine environment. Aims. To identify contributing factors for initiation of conceptus elongation in vitro, this study evaluated differential metabolite abundance within media following culture of blastocysts within unmodified alginate (ALG) or Arg-Gly-Asp (RGD)-modified alginate hydrogel culture systems. Methods. Blastocysts were harvested from pregnant gilts, encapsulated within ALG or RGD or as non-encapsulated control blastocysts (CONT), and cultured. At the termination of 96 h culture, media were separated into blastocyst media groups: non-encapsulated control blastocysts (CONT); ALG and RGD blastocysts with no morphological change (ALGâ and RGDâ); ALG and RGD blastocysts with morphological changes (ALG+ and RGD+) and evaluated for non-targeted metabolomic profiling by liquid chromatography (LC)âmass spectrometry (MS) techniques and gas chromatographyâ (GCâMS). Key results. Analysis of variance identified 280 (LCâMS) and 1 (GCâMS) compounds that differed (P \u3c 0.05), of which 134 (LCâMS) and 1 (GCâMS) were annotated. Metabolites abundance between ALG+ vs ALGâ, RGD+ vs RGDâ, and RGD+ vs ALG+ were further investigated to identify potential differences in metabolic processes during the initiation of elongation. Conclusions. This study identified changes in phospholipid, glycosphingolipid, lipid signalling, and amino acid metabolic processes as potential RGD-independent mechanisms of elongation and identified changes in lysophosphatidylcholine and sphingolipid secretions during RGD-mediated elongation. Implications. These results illustrate changes in phospholipid and sphingolipid metabolic processes and secretions may act as mediators of the RGD-integrin adhesion that promotes porcine conceptus elongation
Metabolic compounds within the porcine uterine environment are unique to the type of conceptus present during the early stages of blastocyst elongation
The objective of this study was to identify metabolites within the porcine uterine milieu during the early stages of blastocyst elongation. At Days 9, 10, or 11 of gestation, reproductive tracts of White crossâbred gilts (n = 38) were collected immediately following harvest and flushed with Roswell Park Memorial Instituteâ1640 medium. Conceptus morphologies were assessed from each pregnancy and corresponding uterine flushings were assigned to one of five treatment groups based on these morphologies: (a) uniform spherical (n = 8); (b) heterogeneous spherical and ovoid (n = 8); (c) uniform ovoid (n = 8); (d) heterogeneous ovoid and tubular (n = 8); and (e) uniform tubular (n = 6). Uterine flushings from these pregnancies were submitted for nontargeted profiling by gas chromatographyâmass spectrometry (GCâMS) and ultra performance liquid chromatography (UPLC)âMS techniques. Unsupervised multivariate principal component analysis (PCA) was performed using pcaMethods and univariate analysis of variance was performed in R with false discovery rate (FDR) adjustment. PCA analysis of the GCâMS and UPLCâMS data identified 153 and 104 metabolites, respectively. After FDR adjustment of the GCâMS and UPLCâMS data, 38 and 59 metabolites, respectively, differed (p \u3c .05) in uterine flushings from pregnancies across the five conceptus stages. Some metabolites were greater (p \u3c .05) in abundance for uterine flushings containing earlier stage conceptuses (i.e., spherical), such as uric acid, tryptophan, and tyrosine. In contrast, some metabolites were greater (
A line confusion limited millimeter survey of Orion KL (I): sulfur carbon chains
We perform a sensitive (line confusion limited), single-side band spectral
survey towards Orion KL with the IRAM 30m telescope, covering the following
frequency ranges: 80-115.5 GHz, 130-178 GHz, and 197-281 GHz. We detect more
than 14 400 spectral features of which 10 040 have been identified up to date
and attributed to 43 different molecules, including 148 isotopologues and lines
from vibrationally excited states. In this paper, we focus on the study of OCS,
HCS+, H2CS, CS, CCS, C3S, and their isotopologues. In addition, we map the OCS
J=18-17 line and complete complementary observations of several OCS lines at
selected positions around Orion IRc2 (the position selected for the survey). We
report the first detection of OCS v2 = 1 and v3 = 1 vibrationally excited
states in space and the first detection of C3S in warm clouds. Most of CCS, and
almost all C3S, line emission arises from the hot core indicating an
enhancement of their abundances in warm and dense gas. Column densities and
isotopic ratios have been calculated using a large velocity gradient (LVG)
excitation and radiative transfer code (for the low density gas components) and
a local thermal equilibrium (LTE) code (appropriate for the warm and dense hot
core component), which takes into account the different cloud components known
to exist towards Orion KL, the extended ridge, compact ridge, plateau, and hot
core. The vibrational temperature derived from OCS v2 = 1 and v3 = 1 levels is
about 210 K, similar to the gas kinetic temperature in the hot core. These OCS
high energy levels are probably pumped by absorption of IR dust photons. We
derive an upper limit to the OC3S, H2CCS, HNCS, HOCS+, and NCS column
densities. Finally, we discuss the D/H abundance ratio and infer the following
isotopic abundances: 12C/13C=45+-20, 32S/34S=20+-6, 32S/33S=75+-29, and
16O/18O=250+-135.Comment: Accepted for publication in A&
Vancomycin Heteroresistance Is Associated with Reduced Mortality in ST239 Methicillin-Resistant Staphylococcus aureus Blood Stream Infections
Background: Despite hVISA infections being associated with vancomycin treatment failure, no previous study has been able to detect a mortality difference between heteroresistant vancomycin intermediate Staphylococcus aureus (hVISA) and vancomycin susceptible Staphylococcus aureus (VSSA) bloodstream infections (BSI)
Risk of COVID-19 after natural infection or vaccination
BACKGROUND: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection.
METHODS: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 \u3e7-15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures.
FINDINGS: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05-0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01-0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease.
INTERPRETATION: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection.
FUNDING: National Institutes of Health
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