247 research outputs found

    The design of a common lunar lander

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    The Austin Cynthesis Corporation was formed to respond to a Request for Proposal for the design of a Common Lunar Lander (CLL) capable of carrying lightweight (less than 500 kg), unspecified payload to the moon. This Final Design Report Document includes information on the requirements for the design project; the ideas proposed as solutions to the design problem; the work which has been completed in support of the design effort; justifications, validations, and verifications of decisions made during the project; and suggestions for future work to be done in support of the project. A project schedule, including current status of the items included on the schedule, as well as cost and management summaries is also included

    Invariant Peano curves of expanding Thurston maps

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    We consider Thurston maps, i.e., branched covering maps f ⁣:S2S2f\colon S^2\to S^2 that are postcritically finite. In addition, we assume that ff is expanding in a suitable sense. It is shown that each sufficiently high iterate F=fnF=f^n of ff is semi-conjugate to zd ⁣:S1S1z^d\colon S^1\to S^1, where dd is equal to the degree of FF. More precisely, for such an FF we construct a Peano curve γ ⁣:S1S2\gamma\colon S^1\to S^2 (onto), such that Fγ(z)=γ(zd)F\circ \gamma(z) = \gamma(z^d) (for all zS1z\in S^1).Comment: 63 pages, 12 figure

    Data Linkage for Optimizing Rectal Cancer Care in Alberta

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    Introduction Despite good overall care in Alberta Health Services the local recurrence rates are higher than what is accepted as standard of care for rectal cancer treatment. There are variations in pre-operative staging, application of best surgical techniques and pathological grading, use of neoadjuvant and adjuvant therapies, and in clinical reporting. Objectives and Approach We aimed at reducing the variations through the design and implementation of a provincial clinical pathway for rectal cancer by 2018. Our approaches included: 1) multidisciplinary tumor board consultation together with physician education sessions in reviewing standards of care and quality metrics; 2) data linkage and analysis based on chart reviews and extraction of data from Alberta Cancer Registry; and 3) production of provincial reports and individual feedbacks to physicians. CancerControl Alberta and Cancer Strategic Clinical Network collaborated in the linkage and analysis of data as well as mobilization oncology physicians to the initiative. Results A review of a set of metrics for producing individual and provincial feedback reports to rectal cancer physicians. The set has 24 key quality metrics includes five, four, eight, and six metrics for radiologists, pathologists, oncologists, and surgeons respectively. Thirty-two surgeons have received individual physician feedback reports. Feedback reports for radiologist, pathologist and oncologist are being finalized with input from key opinion leaders in each physician group. Key impacts to the quality of rectal cancer diagnosis, treatment, and care between 2013 and 2015 include increases in use of rectal cancer pre-operative MRIs for curative resections (+23%), completeness of synoptic MRI reports for pre-operative MRIs (+21%), grade 3 TME of curative resections (+4%), and pathologic reporting of TME assessments (+2%). Conclusion/Implications Physician feedback report system will enable the Alberta rectal cancer community to sustain the results and address strategies to continuously enhance the quality of rectal cancer care and survival. We recommend ongoing annual dissemination of feedback reports to support continuous improvement of rectal cancer care

    Changes of the Membrane Lipid Organization Characterized by Means of a New Cholesterol-Pyrene Probe

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    We synthesized 3β-hydroxy-pregn-5-ene-21-(1-methylpyrenyl)-20-methylidene (Py-met-chol), consisting of cholesterol steroid rings connected to a pyrene group via a linker without polar atoms. This compound has interesting spectroscopic properties when probing membranes: 1), The pyrene has hypochromic properties resulting from probe self-association processes in membranes. Using liposomes of various lipid compositions, we determined the association constants of the probe (K): KDOPC ≫ KPOPC ≫ KDMPC > KDMPC/15 mol % Chol > KDMPC/30 mol % Chol. This indicates a better probe solvation in saturated than in unsaturated lipids, and this effect is enhanced as the cholesterol concentration increases. 2), The pyrene fluorophore is characterized by monomer (I1–I5) and excimer (IE) emission bands. In model membranes, I1/I3 and IE/I3 ratios revealed a correlation between the polarity of the lipid core of the membrane and the amount of cholesterol. 3), Using this probe, we monitored the first steps of the signaling pathway of the mouse δ-opioid receptor, a G-protein-coupled receptor. The thickness of the membrane around this receptor is known to change after agonist binding. Fluorescence spectra of living Chinese hamster ovary cells overexpressing mouse δ-opioid receptor specifically revealed the agonist binding. These results indicate that Py-met-chol may be useful for screening ligands of this family of receptors

    A Large Maize (Zea mays L.) SNP Genotyping Array: Development and Germplasm Genotyping, and Genetic Mapping to Compare with the B73 Reference Genome

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    SNP genotyping arrays have been useful for many applications that require a large number of molecular markers such as high-density genetic mapping, genome-wide association studies (GWAS), and genomic selection. We report the establishment of a large maize SNP array and its use for diversity analysis and high density linkage mapping. The markers, taken from more than 800,000 SNPs, were selected to be preferentially located in genes and evenly distributed across the genome. The array was tested with a set of maize germplasm including North American and European inbred lines, parent/F1 combinations, and distantly related teosinte material. A total of 49,585 markers, including 33,417 within 17,520 different genes and 16,168 outside genes, were of good quality for genotyping, with an average failure rate of 4% and rates up to 8% in specific germplasm. To demonstrate this array's use in genetic mapping and for the independent validation of the B73 sequence assembly, two intermated maize recombinant inbred line populations – IBM (B73×Mo17) and LHRF (F2×F252) – were genotyped to establish two high density linkage maps with 20,913 and 14,524 markers respectively. 172 mapped markers were absent in the current B73 assembly and their placement can be used for future improvements of the B73 reference sequence. Colinearity of the genetic and physical maps was mostly conserved with some exceptions that suggest errors in the B73 assembly. Five major regions containing non-colinearities were identified on chromosomes 2, 3, 6, 7 and 9, and are supported by both independent genetic maps. Four additional non-colinear regions were found on the LHRF map only; they may be due to a lower density of IBM markers in those regions or to true structural rearrangements between lines. Given the array's high quality, it will be a valuable resource for maize genetics and many aspects of maize breeding

    Systemic Maternal Inflammation and Neonatal Hyperoxia Induces Remodeling and Left Ventricular Dysfunction in Mice

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    The impact of the neonatal environment on the development of adult cardiovascular disease is poorly understood. Systemic maternal inflammation is linked to growth retardation, preterm birth, and maturation deficits in the developing fetus. Often preterm or small-for-gestational age infants require medical interventions such as oxygen therapy. The long-term pathological consequences of medical interventions on an immature physiology remain unknown. In the present study, we hypothesized that systemic maternal inflammation and neonatal hyperoxia exposure compromise cardiac structure, resulting in LV dysfunction during adulthood.Pregnant C3H/HeN mice were injected on embryonic day 16 (E16) with LPS (80 µg/kg; i.p.) or saline. Offspring were placed in room air (RA) or 85% O(2) for 14 days and subsequently maintained in RA. Cardiac echocardiography, cardiomyocyte contractility, and molecular analyses were performed. Echocardiography revealed persistent lower left ventricular fractional shortening with greater left ventricular end systolic diameter at 8 weeks in LPS/O(2) than in saline/RA mice. Isolated cardiomyocytes from LPS/O(2) mice had slower rates of contraction and relaxation, and a slower return to baseline length than cardiomyocytes isolated from saline/RA controls. α-/β-MHC ratio was increased and Connexin-43 levels decreased in LPS/O(2) mice at 8 weeks. Nox4 was reduced between day 3 and 14 and capillary density was lower at 8 weeks of life in LPS/O(2) mice.These results demonstrate that systemic maternal inflammation combined with neonatal hyperoxia exposure induces alterations in cardiac structure and function leading to cardiac failure in adulthood and supports the importance of the intrauterine and neonatal milieu on adult health

    Early Left-Hemispheric Dysfunction of Face Processing in Congenital Prosopagnosia: An MEG Study

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    Electrophysiological research has demonstrated the relevance to face processing of a negative deflection peaking around 170 ms, labelled accordingly as N170 in the electroencephalogram (EEG) and M170 in magnetoencephalography (MEG). The M170 was shown to be sensitive to the inversion of faces and to familiarity-two factors that are assumed to be crucial for congenital prosopagnosia. In order to locate the cognitive dysfunction and its neural correlates, we investigated the time course of neural activity in response to these manipulations.Seven individuals with congenital prosopagnosia and seven matched controls participated in the experiment. To explore brain activity with high accuracy in time, we recorded evoked magnetic fields (275 channel whole head MEG) while participants were looking at faces differing in familiarity (famous vs. unknown) and orientation (upright vs. inverted). The underlying neural sources were estimated by means of the least square minimum-norm-estimation (L2-MNE) approach.The behavioural data corroborate earlier findings on impaired configural processing in congenital prosopagnosia. For the M170, the overall results replicated earlier findings, with larger occipito-temporal brain responses to inverted than upright faces, and more right- than left-hemispheric activity. Compared to controls, participants with congenital prosopagnosia displayed a general decrease in brain activity, primarily over left occipitotemporal areas. This attenuation did not interact with familiarity or orientation.The study substantiates the finding of an early involvement of the left hemisphere in symptoms of prosopagnosia. This might be related to an efficient and overused featural processing strategy which serves as a compensation of impaired configural processing

    Maize Production in a Changing Climate

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    Plant breeding and improved management options have made remarkable progress in increasing crop yields during the past century. However, climate change projections suggest that large yield losses will be occurring in many regions, particularly within sub-Saharan Africa. The development of climate-ready germplasm to offset these losses is of the upmost importance. Given the time lag between the development of improved germplasm and adoption in farmers’ fields, the development of improved breeding pipelines needs to be a high priority. Recent advances in molecular breeding provide powerful tools to accelerate breeding gains and dissect stress adaptation. This review focuses on achievements in stress tolerance breeding and physiology and presents future tools for quick and efficient germplasm development. Sustainable agronomic and resource management practices can effectively contribute to climate change mitigation. Management options to increase maize system resilience to climate-related stresses and mitigate the effects of future climate change are also discussed

    Benthic and Hyporheic Macroinvertebrate Distribution Within the Heads and Tails of Riffles During Baseflow Conditions

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    The distribution of lotic fauna is widely acknowledged to be patchy reflecting the interaction between biotic and abiotic factors. In an in-situ field study, the distribution of benthic and hyporheic invertebrates in the heads (downwelling) and tails (upwelling) of riffles were examined during stable baseflow conditions. Riffle heads were found to contain a greater proportion of interstitial fine sediment than riffle tails. Significant differences in the composition of benthic communities were associated with the amount of fine sediment. Riffle tail habitats supported a greater abundance and diversity of invertebrates sensitive to fine sediment such as EPT taxa. Shredder feeding taxa were more abundant in riffle heads suggesting greater availability of organic matter. In contrast, no significant differences in the hyporheic community were recorded between riffle heads and tails. We hypothesise that clogging of hyporheic interstices with fine sediments may have resulted in the homogenization of the invertebrate community by limiting faunal movement into the hyporheic zone at both the riffle head and tail. The results suggest that vertical hydrological exchange significantly influences the distribution of fine sediment and macroinvertebrate communities at the riffle scale
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