44 research outputs found

    Selecting the geology filter wavelengths for the ExoMars Panoramic Camera Instrument

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    The Panoramic Camera (PanCam) instrument will provide surface remote sensing data for the ExoMars mission. A combination of wide-angle stereo, multispectral, and high resolution imagery will generate contextual geological information to help inform which scientific targets should be selected for drilling and analysis. One component of the PanCam dataset is narrowband multispectral imaging in the visible to near infrared, which utilises a dedicated set of 12 “geology” filters of predetermined wavelength and bandwidth to view the terrain, and provide information on composition and putative mineralogy. The centre wavelengths and bandwidths of these filters were optimised to account for the highly diverse mineralogical terrains the ExoMars rover will hopefully encounter. Six new alternative test filter sets were created, each optimised for the detection of either: sulfates, phyllosilicates, ferric oxides, mafic silicates, iron absorptions, and minor hydration absorptions. These six filter sets were cross-tested using database mineral reflectance spectra and Mars analogue rock multispectral data to find the best performing filter set. Once selected, the bandwidths of this filter set were also optimised. The filter set optimised to ferric oxide minerals was able to most accurately represent rock multispectral data, as well as capture subtle spectral features of hydrated minerals, including sulfates, phyllosilicates, and carbonates. These filters differ from those used on past missions (e.g., Pathfinder, Mars Exploration Rover) and represent the next evolutionary stage in PanCam instrument development. When compared to past filter sets, the updated ExoMars filters capture rock and mineral spectral data more effectively, enhancing the ability of the ExoMars PanCam to detect lithological and compositional variation within an outcrop

    Astrobiological Considerations for the Selection of the Geological Filters on the ExoMars PanCam Instrument

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    The Panoramic Camera (PanCam) instrument will provide visible–near IR multispectral imaging of the ExoMars rover's surroundings to identify regions of interest within the nearby terrain. This multispectral capability is dependant upon the 12 preselected “geological” filters that are integrated into two wide-angle cameras. First devised by the Imager for Mars Pathfinder team to detect iron oxides, this baseline filter set has remained largely unchanged for subsequent missions (Mars Exploration Rovers, Beagle 2, Phoenix) despite the advancing knowledge of the mineralogical diversity on Mars. Therefore, the geological filters for the ExoMars PanCam will be redesigned to accommodate the astrobiology focus of ExoMars, where hydrated mineral terrains (evidence of past liquid water) will be priority targets. Here, we conduct an initial investigation into new filter wavelengths for the ExoMars PanCam and present results from tests performed on Mars analog rocks. Two new filter sets were devised: one with filters spaced every 50 nm (“F1-12”) and another that utilizes a novel filter selection method based upon hydrated mineral reflectance spectra (“F2-12”). These new filter sets, along with the Beagle 2 filter set (currently the baseline for the ExoMars PanCam), were tested on their ability to identify hydrated minerals and biosignatures present in Mars analog rocks. The filter sets, with varying degrees of ability, detected the spectral features of minerals jarosite, opaline silica, alunite, nontronite, and siderite present in these rock samples. None of the filter sets, however, were able to detect fossilized biomat structures and small (<2 mm) mineralogical heterogeneities present in silica sinters. Both new filter sets outperformed the Beagle 2 filters, with F2-12 detecting the most spectral features produced by hydrated minerals and providing the best discrimination between samples. Future work involving more extensive testing on Mars analog samples that exhibit a wider range of mineralogies would be the next step in carefully evaluating the new filter sets

    Expression profiling of potato germplasm differentiated in quality traits leads to the identification of candidate flavour and texture genes

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    Quality traits such as flavour and texture are assuming a greater importance in crop breeding programmes. This study takes advantage of potato germplasm differentiated in tuber flavour and texture traits. A recently developed 44 000-element potato microarray was used to identify tuber gene expression profiles that correspond to differences in tuber flavour and texture as well as carotenoid content and dormancy characteristics. Gene expression was compared in two Solanum tuberosum group Phureja cultivars and two S. tuberosum group Tuberosum cultivars; 309 genes were significantly and consistently up-regulated in Phureja, whereas 555 genes were down-regulated. Approximately 46% of the genes in these lists can be identified from their annotation and amongst these are candidates that may underpin the Phureja/Tuberosum trait differences. For example, a clear difference in the cooked tuber volatile profile is the higher level of the sesquiterpene α-copaene in Phureja compared with Tuberosum. A sesquiterpene synthase gene was identified as being more highly expressed in Phureja tubers and its corresponding full-length cDNA was demonstrated to encode α-copaene synthase. Other potential ‘flavour genes’, identified from their differential expression profiles, include those encoding branched-chain amino acid aminotransferase and a ribonuclease suggesting a mechanism for 5′-ribonucleotide formation in potato tubers on cooking. Major differences in the expression levels of genes involved in cell wall biosynthesis (and potentially texture) were also identified, including genes encoding pectin acetylesterase, xyloglucan endotransglycosylase and pectin methylesterase. Other gene expression differences that may impact tuber carotenoid content and tuber life-cycle phenotypes are discussed

    Why Does Exercise “Triggerâ€? Adaptive Protective Responses in the Heart?

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    Numerous epidemiological studies suggest that individuals who exercise have decreased cardiac morbidity and mortality. Pre-clinical studies in animal models also find clear cardioprotective phenotypes in animals that exercise, specifically characterized by lower myocardial infarction and arrhythmia. Despite the clear benefits, the underlying cellular and molecular mechanisms that are responsible for exercise preconditioning are not fully understood. In particular, the adaptive signaling events that occur during exercise to “trigger� cardioprotection represent emerging paradigms. In this review, we discuss recent studies that have identified several different factors that appear to initiate exercise preconditioning. We summarize the evidence for and against specific cellular factors in triggering exercise adaptations and identify areas for future study

    Diurnal timing of nonmigratory movement by birds: the importance of foraging spatial scales

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    Timing of activity can reveal an organism's efforts to optimize foraging either by minimizing energy loss through passive movement or by maximizing energetic gain through foraging. Here, we assess whether signals of either of these strategies are detectable in the timing of activity of daily, local movements by birds. We compare the similarities of timing of movement activity among species using six temporal variables: start of activity relative to sunrise, end of activity relative to sunset, relative speed at midday, number of movement bouts, bout duration and proportion of active daytime hours. We test for the influence of flight mode and foraging habitat on the timing of movement activity across avian guilds. We used 64 570 days of GPS movement data collected between 2002 and 2019 for local (non‐migratory) movements of 991 birds from 49 species, representing 14 orders. Dissimilarity among daily activity patterns was best explained by flight mode. Terrestrial soaring birds began activity later and stopped activity earlier than pelagic soaring or flapping birds. Broad‐scale foraging habitat explained less of the clustering patterns because of divergent timing of active periods of pelagic surface and diving foragers. Among pelagic birds, surface foragers were active throughout all 24 hrs of the day while diving foragers matched their active hours more closely to daylight hours. Pelagic surface foragers also had the greatest daily foraging distances, which was consistent with their daytime activity patterns. This study demonstrates that flight mode and foraging habitat influence temporal patterns of daily movement activity of birds.We thank the Nature Conservancy, the Bailey Wildlife Foundation, the Bluestone Foundation, the Ocean View Foundation, Biodiversity Research Institute, the Maine Outdoor Heritage Fund, the Davis Conservation Foundation and The U.S. Department of Energy (DE‐EE0005362), and the Darwin Initiative (19-026), EDP S.A. ‘Fundação para a Biodiversidade’ and the Portuguese Foundation for Science and Technology (FCT) (DL57/2019/CP 1440/CT 0021), Enterprise St Helena (ESH), Friends of National Zoo Conservation Research Grant Program and Conservation Nation, ConocoPhillips Global Signature Program, Maryland Department of Natural Resources, Cellular Tracking Technologies and Hawk Mountain Sanctuary for providing funding and in-kind support for the GPS data used in our analyses

    Health outcomes among HIV-positive Latinos initiating antiretroviral therapy in North America versus Central and South America

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    Introduction: Latinos living with HIV in the Americas share a common ethnic and cultural heritage. In North America, Latinos have a relatively high rate of new HIV infections but lower rates of engagement at all stages of the care continuum, whereas in Latin America antiretroviral therapy (ART) services continue to expand to meet treatment needs. In this analysis, we compare HIV treatment outcomes between Latinos receiving ART in North America versus Latin America. Methods: HIV-positive adults initiating ART at Caribbean, Central and South America Network for HIV (CCASAnet) sites were compared to Latino patients (based on country of origin or ethnic identity) starting treatment at North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) sites in the United States and Canada between 2000 and 2011. Cox proportional hazards models compared mortality, treatment interruption, antiretroviral regimen change, virologic failure and loss to follow-up between cohorts. Results: The study included 8400 CCASAnet and 2786 NA-ACCORD patients initiating ART. CCASAnet patients were younger (median 35 vs. 37 years), more likely to be female (27% vs. 20%) and had lower nadir CD4 count (median 148 vs. 195 cells/µL, p<0.001 for all). In multivariable analyses, CCASAnet patients had a higher risk of mortality after ART initiation (adjusted hazard ratio (AHR) 1.61; 95% confidence interval (CI): 1.32 to 1.96), particularly during the first year, but a lower hazard of treatment interruption (AHR: 0.46; 95% CI: 0.42 to 0.50), change to second-line ART (AHR: 0.56; 95% CI: 0.51 to 0.62) and virologic failure (AHR: 0.52; 95% CI: 0.48 to 0.57). Conclusions: HIV-positive Latinos initiating ART in Latin America have greater continuity of treatment but are at higher risk of death than Latinos in North America. Factors underlying these differences, such as HIV testing, linkage and access to care, warrant further investigation

    Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

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    BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

    The protocol for the Cannabidiol in children with refractory epileptic encephalopathy (CARE-E) study: a phase 1 dosage escalation study

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    Background: Initial studies suggest pharmaceutical grade cannabidiol (CBD) can reduce the frequency of convulsive seizures and lead to improvements in quality of life in children affected by epileptic encephalopathies. With limited access to pharmaceutical CBD, Cannabis extracts in oil are becoming increasingly available. Physicians show reluctance to recommend Cannabis extracts given the lack of high quality safety data especially regarding the potential for harm caused by other cannabinoids, such as Δ9-tetrahydrocannabinol (Δ9-THC). The primary aims of the study presented in this protocol are (i) To determine whether CBD enriched Cannabis extract is safe and well-tolerated for pediatric patients with refractory epilepsy, (ii) To monitor the effects of CBD-enriched Cannabis extract on the frequency and duration of seizure types and on quality of life. Methods: Twenty-eight children with treatment resistant epileptic encephalopathy ranging in age from 1 to 10 years will be recruited in four Canadian cities into an open-label, dose-escalation phase 1 trial. The primary objectives for the study are (i) To determine if the CBD-enriched Cannabis herbal extract is safe and well-tolerated for pediatric patients with treatment resistant epileptic encephalopathy and (ii) To determine the effect of CBD-enriched Cannabis herbal extract on the frequency and duration of seizures. Secondary objectives include (i) To determine if CBD-enriched Cannabis herbal extracts alter steady-state levels of co-administered anticonvulsant medications. (ii) To assess the relation between dose escalation and quality of life measures, (iii) To determine the relation between dose escalation and steady state trough levels of bioactive cannabinoids. (iv) To determine the relation between dose escalation and incidence of adverse effects. Discussion: This paper describes the study design of a phase 1 trial of CBD-enriched Cannabis herbal extract in children with treatment-resistant epileptic encephalopathy. This study will provide the first high quality analysis of safety of CBD-enriched Cannabis herbal extract in pediatric patients in relation to dosage and pharmacokinetics of the active cannabinoids. Trial registration http://clinicaltrials.gov [Internet]. Bethesda (MD): National Library of Medicine (US). 2016 Dec 16. Identifier NCT03024827, Cannabidiol in Children with Refractory Epileptic Encephalopathy: CARE-E; 2017 Jan 19 [cited 2017 Oct]; Available from: http://clinicaltrials.gov/ct2/show/NCT03024827Medicine, Faculty ofNon UBCPediatrics, Department ofReviewedFacult
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