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Sökning: WFRF:(Gaston L)

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  • Bernal, Ximena E., et al. (författare)
  • Empowering Latina scientists
  • 2019
  • Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 363:6429, s. 825-826
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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  • Phillips, M. M., et al. (författare)
  • Carnegie Supernova Project-II : Extending the Near-infrared Hubble Diagram for Type Ia Supernovae to z ∼ 0.1
  • 2019
  • Ingår i: Publications of the Astronomical Society of the Pacific. - : IOP Publishing. - 0004-6280 .- 1538-3873. ; 131:995
  • Tidskriftsartikel (refereegranskat)abstract
    • The Carnegie Supernova Project-II (CSP-II) was an NSF-funded, four-year program to obtain optical and near-infrared observations of a Cosmology sample of similar to 100 Type. Ia supernovae located in the smooth Hubble flow (0.03 less than or similar to z less than or similar to 0.10). Light curves were also obtained of a Physics sample composed of 90 nearby Type. Ia supernovae at z <= 0.04 selected for near-infrared spectroscopic timeseries observations. The primary emphasis of the CSP-II is to use the combination of optical and near-infrared photometry to achieve a distance precision of better than 5%. In this paper, details of the supernova sample, the observational strategy, and the characteristics of the photometric data are provided. In a companion paper, the near-infrared spectroscopy component of the project is presented.
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  • Stritzinger, Maximilian, et al. (författare)
  • THE CARNEGIE SUPERNOVA PROJECT : SECOND PHOTOMETRY DATA RELEASE OF LOW-REDSHIFT TYPE Ia SUPERNOVAE
  • 2011
  • Ingår i: Astronomical Journal. - : American Astronomical Society. - 0004-6256 .- 1538-3881. ; 142:5, s. 156-
  • Tidskriftsartikel (refereegranskat)abstract
    • The Carnegie Supernova Project (CSP) was a five-year observational survey conducted at Las Campanas Observatory that obtained, among other things, high-quality light curves of similar to 100 low-redshift Type Ia supernovae (SNe Ia). Presented here is the second data release of nearby SN Ia photometry consisting of 50 objects, with a subset of 45 having near-infrared follow-up observations. Thirty-three objects have optical pre-maximum coverage with a subset of 15 beginning at least five days before maximum light. In the near-infrared, 27 objects have coverage beginning before the epoch of B-band maximum, with a subset of 13 beginning at least five days before maximum. In addition, we present results of a photometric calibration program to measure the CSP optical (uBgVri) bandpasses with an accuracy of similar to 1%. Finally, we report the discovery of a second SN Ia, SN 2006ot, similar in its characteristics to the peculiar SN 2006bt.
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  • Bassani, Carlos L., et al. (författare)
  • Nanocrystal Assemblies : Current Advances and Open Problems
  • 2024
  • Ingår i: ACS Nano. - 1936-0851. ; 18:23, s. 14791-14840
  • Forskningsöversikt (refereegranskat)abstract
    • We explore the potential of nanocrystals (a term used equivalently to nanoparticles) as building blocks for nanomaterials, and the current advances and open challenges for fundamental science developments and applications. Nanocrystal assemblies are inherently multiscale, and the generation of revolutionary material properties requires a precise understanding of the relationship between structure and function, the former being determined by classical effects and the latter often by quantum effects. With an emphasis on theory and computation, we discuss challenges that hamper current assembly strategies and to what extent nanocrystal assemblies represent thermodynamic equilibrium or kinetically trapped metastable states. We also examine dynamic effects and optimization of assembly protocols. Finally, we discuss promising material functions and examples of their realization with nanocrystal assemblies.
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  • Horvath, I., et al. (författare)
  • Exhaled breath condensate: methodological recommendations and unresolved questions
  • 2005
  • Ingår i: Eur Respir J. ; 26:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Collection of exhaled breath condensate (EBC) is a noninvasive method for obtaining samples from the lungs. EBC contains large number of mediators including adenosine, ammonia, hydrogen peroxide, isoprostanes, leukotrienes, nitrogen oxides, peptides and cytokines. Concentrations of these mediators are influenced by lung diseases and modulated by therapeutic interventions. Similarly EBC pH also changes in respiratory diseases. The aim of the American Thoracic Society/European Respiratory Society Task Force on EBC was to identify the important methodological issues surrounding EBC collection and assay, to provide recommendations for the measurements and to highlight areas where further research is required. Based on the currently available evidence and the consensus of the expert panel for EBC collection, the following general recommendations were put together for oral sample collection: collect during tidal breathing using a noseclip and a saliva trap; define cooling temperature and collection time (10 min is generally sufficient to obtain 1-2 mL of sample and well tolerated by patients); use inert material for condenser; do not use resistor and do not use filter between the subject and the condenser. These are only general recommendations and certain circumstances may dictate variation from them. Important areas for future research involve: ascertaining mechanisms and site of exhaled breath condensate particle formation; determination of dilution markers; improving reproducibility; employment of EBC in longitudinal studies; and determining the utility of exhaled breath condensate measures for the management of individual patients. These studies are required before recommending this technique for use in clinical practice.
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  • Burns, Christopher R., et al. (författare)
  • THE CARNEGIE SUPERNOVA PROJECT : LIGHT-CURVE FITTING WITH SNooPy
  • 2011
  • Ingår i: Astronomical Journal. - : American Astronomical Society. - 0004-6256 .- 1538-3881. ; 141:1, s. 19-
  • Tidskriftsartikel (refereegranskat)abstract
    • In providing an independent measure of the expansion history of the universe, the Carnegie Supernova Project (CSP) has observed 71 high-z Type Ia supernovae (SNe Ia) in the near-infrared bands Y and J. These can be used to construct rest-frame i-band light curves which, when compared to a low-z sample, yield distance moduli that are less sensitive to extinction and/or decline-rate corrections than in the optical. However, working with NIR observed and i-band rest-frame photometry presents unique challenges and has necessitated the development of a new set of observational tools in order to reduce and analyze both the low-z and high-z CSP sample. We present in this paper the methods used to generate uBVgriYJH light-curve templates based on a sample of 24 high-quality low-z CSP SNe. We also present two methods for determining the distances to the hosts of SN Ia events. A larger sample of 30 low-z SNe Ia in the Hubble flow is used to calibrate these methods. We then apply the method and derive distances to seven galaxies that are so nearby that their motions are not dominated by the Hubble flow.
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  • Courtade, Gaston, et al. (författare)
  • The carbohydrate-binding module and linker of a modular lytic polysaccharide monooxygenase promote localized cellulose oxidation
  • 2018
  • Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 293:34, s. 13006-13015
  • Tidskriftsartikel (refereegranskat)abstract
    • Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that catalyze the oxidative cleavage of polysaccharides such as cellulose and chitin, a feature that makes them key tools in industrial biomass conversion processes. The catalytic domains of a considerable fraction of LPMOs and other carbohydrate-active enzymes (CAZymes) are tethered to carbohydrate-binding modules (CBMs) by flexible linkers. These linkers preclude X-ray crystallographic studies, and the functional implications of these modular assemblies remain partly unknown. Here, we used NMR spectroscopy to characterize structural and dynamic features of full-length modular ScLPMO10C from Streptomyces coelicolor We observed that the linker is disordered and extended, creating distance between the CBM and the catalytic domain and allowing these domains to move independently of each other. Functional studies with cellulose nanofibrils revealed that most of the substrate-binding affinity of full-length ScLPMO10C resides in the CBM. Comparison of the catalytic performance of full-length ScLPMO10C and its isolated catalytic domain revealed that the CBM is beneficial for LPMO activity at lower substrate concentrations and promotes localized and repeated oxidation of the substrate. Taken together, these results provide a mechanistic basis for understanding the interplay between catalytic domains linked to CBMs in LPMOs and CAZymes in general.
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  • D'Ambro, E. L., et al. (författare)
  • Molecular composition and volatility of isoprene photochemical oxidation secondary organic aerosol under low- and high-NOx conditions
  • 2017
  • Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 17:1, s. 159-174
  • Tidskriftsartikel (refereegranskat)abstract
    • We present measurements of secondary organic aerosol (SOA) formation from isoprene photochemical oxidation in an environmental simulation chamber at a variety of oxidant conditions and using dry neutral seed particles to suppress acid-catalyzed multiphase chemistry. A high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) utilizing iodide-adduct ionization coupled to the Filter Inlet for Gases and Aerosols (FIGAERO) allowed for simultaneous online sampling of the gas and particle composition. Under high-HO2 and low-NO conditions, highly oxygenated (O : C >= 1) C-5 compounds were major components (similar to 50 %) of SOA. The SOA composition and effective volatility evolved both as a function of time and as a function of input NO concentrations. Organic nitrates increased in both the gas and particle phases as input NO increased, but the dominant non-nitrate particle-phase components monotonically decreased. We use comparisons of measured and predicted gas-particle partitioning of individual components to assess the validity of literature-based group-contribution methods for estimating saturation vapor concentrations. While there is evidence for equilibrium partitioning being achieved on the chamber residence timescale (5.2 h) for some individual components, significant errors in group-contribution methods are revealed. In addition, >30% of the SOA mass, detected as low-molecular-weight semivolatile compounds, cannot be reconciled with equilibrium partitioning. These compounds desorb from the FIGAERO at unexpectedly high temperatures given their molecular composition, which is indicative of thermal decomposition of effectively lower-volatility components such as larger molecular weight oligomers.
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  • Denoyes-Rothan, B., et al. (författare)
  • Use of a Reference Octoploid Map for Detecting Homoeologous QTLs Potentially Involved in Viability in the Cultivated Strawberry
  • 2009
  • Ingår i: VI INTERNATIONAL STRAWBERRY SYMPOSIUM. - : INT SOC HORTICULTURAL SCIENCE. ; , s. 537-540
  • Konferensbidrag (refereegranskat)abstract
    • The construction of a reference map of the complex octoploid cultivated strawberry was optimized by comparative mapping between Fragaria showing different levels of ploidy. In addition, this approach is a powerful tool for improving the detection of QTLs, and for a better understanding of the organization of these QTLs. By identifying the homoeologous linkage groups in the complex octoploid cultivated strawberry, potential homoeologous QTLs in Fragaria can be detected. The comparative mapping was based on two populations belonging to two different levels of Fragaria. The linkage map of the complex octoploid cultivated strawberry (Fragaria x ananassa Duch., 2n=8x=56) was based on a segregating population of 213 individuals of a cross between ‘Capitola’ and ‘CF1116’, two genotypes with many contrasting traits. This genetic map was compared to the diploid one, obtained from an interspecific cross between F. vesca and F. bucharica (Sargent et al., 2006). Based on 56 SSR markers common to both diploid and octoploid genetic maps, almost all linkage groups of the genetic octoploid map were arranged into the seven homoeologous groups (HGs) expected for the genus Fragaria, which belongs to the tribe Rosoideae. For each trait, QTLs can potentially be detected on each linkage group belonging to the same HG. Results showed detection of homoeologous chromosomal regions potentially involved in viability of the plant.
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  • Finlayson, L., et al. (författare)
  • The head shaft angle is associated with hip displacement in children at GMFCS levels III-V - A population based study
  • 2018
  • Ingår i: BMC Musculoskeletal Disorders. - : Springer Science and Business Media LLC. - 1471-2474. ; 19:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: An increased Head Shaft Angle (HSA) has been reported as a risk factor for hip displacement in children with cerebral palsy (CP) but opinions differ in the literature. The purpose of this study was to re-evaluate the relationship between HSA and hip displacement in a different population of children with CP. Methods: The Cerebral Palsy Integrated Pathway Scotland surveillance programme includes 95% of all children with CP in Scotland. The pelvic radiographs from 640 children in GMFCS levels III-V were chosen. The most displaced hip was analysed and the radiographs used were those taken at the child's first registration in the database to avoid the potential effects of surveillance on subsequent hip centration. A logistic regression model was used with hip displacement (migration percentage [MP] ≥40%) as outcome and HSA, GMFCS, age and sex as covariates. Results: The MP was ≥40% in 118 hips with a mean HSA of 164° (range 121-180°) and < 40% in 522 hips with a mean HSA of 160° (range 111-180°). The logistic regression analysis showed no significant influence of age and sex on MP in this population but a high GMFCS level was strongly associated with hip displacement. An increased HSA was also associated with hip displacement, a 10° difference in HSA for children adjusted for age, sex, and GMFCS gave an odds ratio of 1.26 for hip displacement equal or above 40% (p = 0.009) and hips with HSA above 164.5 degrees had an odds ratio of 1.96 compared with hips with HSA below 164.5 degrees (p = 0.002). Conclusion: These findings confirm that HSA is associated with hip displacement in children in GMFCS levels III-V.
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  • Folatelli, Gaston, et al. (författare)
  • UNBURNED MATERIAL IN THE EJECTA OF TYPE Ia SUPERNOVAE
  • 2012
  • Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 745:1, s. 74-
  • Tidskriftsartikel (refereegranskat)abstract
    • The presence of unburned material in the ejecta of normal Type Ia supernovae (SNe Ia) is investigated using early-time spectroscopy obtained by the Carnegie Supernova Project. The tell-tale signature of pristine material from a C+O white dwarf progenitor star is the presence of carbon, as oxygen is also a product of carbon burning. The most prominent carbon lines in optical spectra of SNe Ia are expected to arise from C II. We find that at least 30% of the objects in the sample show an absorption at approximate to 6300 angstrom which is attributed to C II lambda 6580. An alternative identification of this absorption as Ha is considered to be unlikely. These findings imply a larger incidence of carbon in SNe Ia ejecta than previously noted. We show how observational biases and physical conditions may hide the presence of weak C II lines, and account for the scarcity of previous carbon detections in the literature. This relatively large frequency of carbon detections has crucial implications on our understanding of the explosive process. Furthermore, the identification of the 6300 angstrom absorptions as carbon would imply that unburned material is present at very low expansion velocities, merely approximate to 1000 km s(-1) above the bulk of Si II. Based on spectral modeling, it is found that the detections are consistent with a mass of carbon of 10(-3) to 10(-2) M-circle dot. The presence of this material so deep in the ejecta would imply substantial mixing, which may be related to asymmetries of the flame propagation. Another possible explanation for the carbon absorptions may be the existence of clumps of unburned material along the line of sight. However, the uniformity of the relation between C II and Si II velocities is not consistent with such small-scale asymmetries. The spectroscopic and photometric properties of SNe Ia with and without carbon signatures are compared. A trend toward bluer color and lower luminosity at maximum light is found for objects which show carbon.
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  • Guex, Leonard Gaston, et al. (författare)
  • Experimental review : chemical reduction of graphene oxide (GO) to reduced graphene oxide (rGO) by aqueous chemistry
  • 2017
  • Ingår i: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; 9:27, s. 9562-9571
  • Forskningsöversikt (refereegranskat)abstract
    • The electrical conductivity of reduced graphene oxide (rGO) obtained from graphene oxide (GO) using sodium borohydride (NaBH4) as a reducing agent has been investigated as a function of time (2 min to 24 h) and temperature (20 degrees C to 80 degrees C). Using a 300 mM aqueous NaBH4 solution at 80 degrees C, reduction of GO occurred to a large extent during the first 10 min, which yielded a conductivity increase of 5 orders of magnitude to 10 S m(-1). During the residual 1400 min of reaction, the reduction rate decreased significantly, eventually resulting in a rGO conductivity of 1500 S m(-1). High resolution XPS measurements showed that C/O increased from 2.2 for the GO to 6.9 for the rGO at the longest reaction times, due to the elimination of oxygen. The steep increase in conductivity recorded during the first 8-12 min of reaction was mainly due to the reduction of C-O (e.g., hydroxyl and epoxy) groups, suggesting the preferential attack of the reducing agent on C-O rather than C=O groups. In addition, the specular variation of the percentage content of C-O bond functionalities with the sum of Csp(2) and Csp(3) indicated that the reduction of epoxy or hydroxyl groups had a greater impact on the restoration of the conductive nature of the graphite structure in rGO. These findings were reflected in the dramatic change in the structural stability of the rGO nanofoams produced by freeze-drying. The reduction protocol in this study allowed to achieve the highest conductivity values reported so far for the aqueous reduction of graphene oxide mediated by sodium borohydride. The 4-probe sheet resistivity approach used to measure the electrical conductivity is also, for the first time, presented in detail for filtrate sheet assemblies' of stacked GO/rGO sheets.
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  • Hollung, Sandra Julsen, et al. (författare)
  • Point prevalence and motor function of children and adolescents with cerebral palsy in Scandinavia and Scotland : a CP-North study
  • 2021
  • Ingår i: Developmental Medicine and Child Neurology. - : Wiley. - 0012-1622 .- 1469-8749. ; 63:6, s. 721-728
  • Tidskriftsartikel (refereegranskat)abstract
    • AIM: To describe the point prevalence of cerebral palsy (CP) and distribution of gross and fine motor function in individuals registered in a CP-North surveillance programme.METHOD: Aggregate data of individuals with CP aged 6 to 19 years, sex, CP subtype, and gross and fine motor function levels were collected from each programme. Overall and age-specific point prevalence of CP was calculated for each programme using 95% confidence intervals. Logistic regression was used to estimate prevalence and CP subtypes with age as the covariate variable. Pearson χ2 tests were used to compare the distributions of CP subtypes, Gross Motor Function Classification System (GMFCS) levels, and Manual Ability Classification System (MACS) levels by age and between programmes.RESULTS: Among 3 759 138 individuals residing in Scandinavia and Scotland, 8278 had a diagnosis of CP (57-59% were males). The overall point prevalence of CP ranged from 2.13 to 2.32 per 1000 residents. Age-specific prevalence in each programme varied with the exception of Denmark. While the proportions of bilateral spastic CP were similar between programmes, there were variations in all other CP subtypes and in GMFCS and MACS levels.INTERPRETATION: While the results of this study may reflect real differences in CP populations between countries, they may not be clinically relevant. The variations may be attributable to differences in the year when each programme was first established, different data collection methods, and country-specific governmental policies.
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  • Hägglund, Gunnar, et al. (författare)
  • Treatment of spasticity in children and adolescents with cerebral palsy in Northern Europe : a CP-North registry study
  • 2021
  • Ingår i: BMC Neurology. - : Springer Science and Business Media LLC. - 1471-2377. ; 21:1
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Spasticity is present in more than 80% of the population with cerebral palsy (CP). The aim of this study was to describe and compare the use of three spasticity reducing methods; Botulinum toxin-A therapy (BTX-A), Selective dorsal rhizotomy (SDR) and Intrathecal baclofen therapy (ITB) among children and adolescents with CP in six northern European countries.METHODS: This registry-based study included population-based data in children and adolescents with CP born 2002 to 2017 and recorded in the follow-up programs for CP in Sweden, Norway, Denmark, Iceland and Scotland, and a defined cohort in Finland.RESULTS: A total of 8,817 individuals were included. The proportion of individuals treated with SDR and ITB was significantly different between the countries. SDR treatment ranged from 0% ( Finland and Iceland) to 3.4% (Scotland) and ITB treatment from 2.2% (Sweden) to 3.7% (Denmark and Scotland). BTX-A treatment in the lower extremities reported 2017-2018 ranged from 8.6% in Denmark to 20% in Norway (p < 0.01). Mean age for undergoing SDR ranged from 4.5 years in Norway to 7.3 years in Denmark (p < 0.01). Mean age at ITB surgery ranged from 6.3 years in Norway to 10.1 years in Finland (p < 0.01). Mean age for BTX-A treatment ranged from 7.1 years in Denmark to 10.3 years in Iceland (p < 0.01). Treatment with SDR was most common in Gross Motor Function Classification System (GMFCS) level III, ITB in level V, and BTX-A in level I. The most common muscle treated with BTX-A was the calf muscle, with the highest proportion in GMFCS level I. BTX-A treatment of hamstring and hip muscles was most common in GMFCS levels IV-V in all countries.CONCLUSION: There were statistically significant differences between countries regarding the proportion of children and adolescents with CP treated with the three spasticity reducing methods, mean age for treatment and treatment related to GMFCS level. This is likely due to differences in the availability of these treatment methods and/or differences in preferences of treatment methods among professionals and possibly patients across countries.
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26.
  • Kattner, ShiAnne, et al. (författare)
  • The Standardizability of Type Ia Supernovae in the Near-Infrared : Evidence for a Peak-Luminosity Versus Decline-Rate Relation in the Near-Infrared
  • 2012
  • Ingår i: Publications of the Astronomical Society of the Pacific. - : IOP Publishing. - 0004-6280 .- 1538-3873. ; 124:912, s. 114-127
  • Tidskriftsartikel (refereegranskat)abstract
    • We analyze the standardizability of Type Ia supernovae (SNe Ia) in the near-infrared (NIR) by investigating the correlation between observed peak NIR (Y JH) absolute magnitude and postmaximum B-band decline rate [Delta m(15)(B)]. A sample of 27 low-redshift SNe Ia with well-observed NIR light curves observed by the Carnegie Supernova Project (CSP) between 2004 and 2007 is used. All 27 objects have premaximum coverage in optical bands, with a subset of 13 having premaximum NIR observations as well; coverage of the other 14 begins shortly after NIR maximum brightness. We describe the methods used to derive light-curve parameters (absolute peak magnitudes and decline rates) from both spline-and template-fitting procedures, and we confirm prior findings that fitting templates to SNe Ia light curves in the NIR is problematic due to the diversity of postmaximum behavior of objects that are characterized by similar Delta m(15)(B) values, especially at high decline rates. Nevertheless, we show that NIR light curves can be reasonably fit with a template, especially if the observations begin within 5 days after NIR maximum. SNe Ia appear to be better standardizable candles in the NIR bands than in the optical bands. For the subset of 13 objects in our data set that excludes the highly reddened and fast-declining SNe Ia and includes only those objects for which NIR observations began prior to 5 days after maximum light, we find modest (1.7 sigma) evidence for a peak-luminosity versus decline-rate relation in Y, and stronger evidence (2.8 sigma) in J and H. Using R-V values differing from the canonical value (R-V = 3.1) is shown to have little effect on the results. A Hubble diagram is presented for the NIR bands and the B band. The resulting scatter for the combined NIR bands is 0.13 mag, while the B band produces a scatter of 0.22 mag. Finally, we find evidence for a bimodal distribution in the NIR absolute magnitudes of fast-declining SNe Ia [Delta m(15)(B) > 1.7]. These data suggest that applying a correction to SNe Ia peak luminosities for decline rate is likely to be beneficial in the J and H bands to make SNe Ia more precise distance indicators, but of only marginal importance in the Y band.
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27.
  • Lopez-Hilfiker, F D, et al. (författare)
  • Molecular Composition and Volatility of Organic Aerosol in the Southeastern U.S.: Implications for IEPOX Derived SOA.
  • 2016
  • Ingår i: Environmental science & technology. - : American Chemical Society (ACS). - 1520-5851 .- 0013-936X. ; 50:5, s. 2200-2209
  • Tidskriftsartikel (refereegranskat)abstract
    • We present measurements as part of the Southern Oxidant and Aerosol Study (SOAS) during which atmospheric aerosol particles were comprehensively characterized. We present results utilizing a Filter Inlet for Gases and AEROsol coupled to a chemical ionization mass spectrometer (CIMS). We focus on the volatility and composition of isoprene derived organic aerosol tracers and of the bulk organic aerosol. By utilizing the online volatility and molecular composition information provided by the FIGAERO-CIMS, we show that the vast majority of commonly reported molecular tracers of isoprene epoxydiol (IEPOX) derived secondary organic aerosol (SOA) is derived from thermal decomposition of accretion products or other low volatility organics having effective saturation vapor concentrations <10(-3) μg m(-3). In addition, while accounting for up to 30% of total submicrometer organic aerosol mass, the IEPOX-derived SOA has a higher volatility than the remaining bulk. That IEPOX-SOA, and more generally bulk organic aerosol in the Southeastern U.S. is comprised of effectively nonvolatile material has important implications for modeling SOA derived from isoprene, and for mechanistic interpretations of molecular tracer measurements. Our results show that partitioning theory performs well for 2-methyltetrols, once accretion product decomposition is taken into account. No significant partitioning delays due to aerosol phase or viscosity are observed, and no partitioning to particle-phase water or other unexplained mechanisms are needed to explain our results.
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28.
  • O'Neil, Lauren Vega, et al. (författare)
  • Creating Connections Between Researchers and Educators
  • 2019
  • Ingår i: Journal of Cognition and Development. - : Informa UK Limited. - 1524-8372 .- 1532-7647. ; 20:2, s. 110-133
  • Tidskriftsartikel (refereegranskat)abstract
    • Translational research involving the development, implementation, and assessment of evidence-based interventions has shown promise in improving outcomes for children from lower socioeconomic-status backgrounds. One such approach involves 2-generation interventions, which target both children and their parents/caregivers. Here we traced the evolution of a 15-year partnership between researchers from the University of Oregon Brain Development Lab and educators from Head Start of Lane County, with a primary goal of developing, implementing, and evaluating a 2-generation intervention. The partnership has produced a successful 2-generation intervention, with current efforts focused on the development of a scaled-up delivery model that can be implemented by Head Start staff and integrated into existing Head Start structure classrooms. Taking a lessons-learned approach and including the perspectives of researchers and educators, we highlight 4 key themes that emerged from this partnership and may be useful to other researchers collaborating with educators to develop evidence-based interventions: 1) employ smaller-scale studies that trade ecological validity for experimental control to establish a proof of concept, 2) adapt to real-world constraints when scaling for broader implementation, 3) consider theoretical insights from smaller-scale studies when developing scalable delivery models, and 4) work together to find novel solutions to common problems. We close with results from a survey of teachers involved in the project, a broad reflection on successes of the collaboration, and a discussion on focusing efforts to sustain the intervention in the future.
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30.
  • Patterson, Allison, et al. (författare)
  • Foraging range scales with colony size in high-latitude seabirds
  • 2022
  • Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 32:17, s. 3800-3807
  • Tidskriftsartikel (refereegranskat)abstract
    • Density-dependent prey depletion around breeding colonies has long been considered an important factor controlling the population dynamics of colonial animals.1, 2, 3, 4 Ashmole proposed that as seabird colony size increases, intraspecific competition leads to declines in reproductive success, as breeding adults must spend more time and energy to find prey farther from the colony.1 Seabird colony size often varies over several orders of magnitude within the same species and can include millions of individuals per colony.5,6 As such, colony size likely plays an important role in determining the individual behavior of its members and how the colony interacts with the surrounding environment.6 Using tracking data from murres (Uria spp.), the world’s most densely breeding seabirds, we show that the distribution of foraging-trip distances scales to colony size0.33 during the chick-rearing stage, consistent with Ashmole’s halo theory.1,2 This pattern occurred across colonies varying in size over three orders of magnitude and distributed throughout the North Atlantic region. The strong relationship between colony size and foraging range means that the foraging areas of some colonial species can be estimated from colony sizes, which is more practical to measure over a large geographic scale. Two-thirds of the North Atlantic murre population breed at the 16 largest colonies; by extrapolating the predicted foraging ranges to sites without tracking data, we show that only two of these large colonies have significant coverage as marine protected areas. Our results are an important example of how theoretical models, in this case, Ashmole’s version of central-place-foraging theory, can be applied to inform conservation and management in colonial breeding species.
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31.
  • Servetto, N., et al. (författare)
  • Molecular responses to ocean acidification in an Antarctic bivalve and an ascidian
  • 2023
  • Ingår i: Science of the Total Environment. - 0048-9697 .- 1879-1026. ; 903
  • Tidskriftsartikel (refereegranskat)abstract
    • Southern Ocean organisms are considered particularly vulnerable to Ocean acidification (OA), as they inhabit cold waters where calcite-aragonite saturation states are naturally low. It is also generally assumed that OA would affect calcifying animals more than non-calcifying animals. In this context, we aimed to study the impact of reduced pH on both types of species: the ascidian Cnemidocarpa verrucosa sp. A, and the bivalve Aequiyoldia eightsii, from an Antarctic fjord. We used gene expression profiling and enzyme activity to study the responses of these two Antarctic benthic species to OA. We report the results of an experiment lasting 66 days, comparing the molecular mechanisms underlying responses under two pCO2 treatments (ambient and elevated pCO2). We observed 224 up-regulated and 111 down-regulated genes (FC >= 2; p-value <= 0.05) in the ascidian. In particular, the decrease in pH caused an upregulation of genes involved in the immune system and antioxidant response. While fewer differentially expressed (DE) genes were observed in the infaunal bivalve, 34 genes were up -regulated, and 69 genes were downregulated (FC >= 2; p-value <= 0.05) in response to OA. We found down -regulated genes involved in the oxidoreductase pathway (such as glucose dehydrogenase and trimethyl lysine dioxygenase), while the heat shock protein 70 was up-regulated. This work addresses the effect of OA in two common, widely distributed Antarctic species, showing striking results. Our major finding highlights the impact of OA on the non-calcifying species, a result that differ from the general trend, which describes a higher impact on calcifying species. This calls for discussion of potential effects on non-calcifying species, such as ascidians, a diverse and abundant group that form extended three-dimensional clusters in shallow waters and shelf areas in the Southern Ocean.
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32.
  • Stritzinger, Maximilian, et al. (författare)
  • THE DISTANCE TO NGC 1316 (FORNAX A) FROM OBSERVATIONS OF FOUR TYPE Ia SUPERNOVAE
  • 2010
  • Ingår i: Astronomical Journal. - : American Astronomical Society. - 0004-6256 .- 1538-3881. ; 140:6, s. 2036-2051
  • Tidskriftsartikel (refereegranskat)abstract
    • The giant elliptical galaxy NGC 1316 (Fornax A) is a well-studied member of the Fornax Cluster and a prolific producer of Type Ia supernovae (SNe Ia), having hosted four observed events since 1980. Here, we present detailed optical-and near-infrared light curves of the spectroscopically normal SN 2006dd. These data are used, along with previously published photometry of the normal SN 1980N and SN 1981D, and the fast-declining, low-luminosity SN 2006mr, to compute independent estimates of the host reddening for each SN, and the distance to NGC 1316. From the three normal SNe, we find a distance of 17.8 +/- 0.3 (random) +/- 0.3 (systematic) Mpc for H-o = 72. Distance moduli derived from the "EBV" and Tripp methods give the values that are mutually consistent with 4%-8%. Moreover, the weighted means of the distance moduli for these three SNe for three methods agree to within 3%. This consistency is encouraging and supports the premise that Type Ia SNe are reliable distance indicators at the 5% precision level or better. On the other hand, the two methods used to estimate the distance of the fast-declining SN 2006mr both yield a distance to NGC 1316 which is 25%-30% larger. This disparity casts doubt on the suitability of fast-declining events for estimating extragalactic distances. Modest-to-negligible host galaxy reddening values are derived for all four SNe. Nevertheless, two of them (SN 2006dd and SN 2006mr) show strong Na I D interstellar lines in the host galaxy system. The strength of this absorption is completely inconsistent with the small reddening values derived from the SN light curves if the gas in NGC 1316 is typical of that found in the interstellar medium of the Milky Way. In addition, the equivalent width of the Na lines in SN 2006dd appears to have weakened significantly some 100-150 days after explosion.
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33.
  • Stritzinger, Maximilian, et al. (författare)
  • The He-Rich Core-Collapse Supernova 2007Y : Observations from X-Ray to Radio Wavelengths
  • 2009
  • Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 696:1, s. 713-728
  • Tidskriftsartikel (refereegranskat)abstract
    • A detailed study spanning approximately a year has been conducted on the Type Ib supernova (SN) 2007Y. Imaging was obtained from X-ray to radio wavelengths, and a comprehensive set of multi-band (w2m2w1u'g'r'i'UBVYJHKs ) light curves and optical spectroscopy is presented. A virtually complete bolometric light curve is derived, from which we infer a 56Ni mass of 0.06 M sun. The early spectrum strongly resembles SN 2005bf and exhibits high-velocity features of Ca II and Hα during late epochs the spectrum shows evidence of an ejecta-wind interaction. Nebular emission lines have similar widths and exhibit profiles that indicate a lack of major asymmetry in the ejecta. Late phase spectra are modeled with a non-LTE code, from which we find 56Ni, O, and total-ejecta masses (excluding He) to be 0.06, 0.2, and 0.42 M sun, respectively, below 4500 km s-1. The 56Ni mass confirms results obtained from the bolometric light curve. The oxygen abundance suggests that the progenitor was most likely a ≈3.3 M sun He core star that evolved from a zero-age-main-sequence mass of 10-13 M sun. The explosion energy is determined to be ≈1050 erg, and the mass-loss rate of the progenitor is constrained from X-ray and radio observations to be lsim10-6 M sun yr-1. SN 2007Y is among the least energetic normal Type Ib SNe ever studied. Partly based on observations collected at the European Southern Observatory, La Silla and Paranal Observatories, Chile (ESO Programme 078.D-0048 and 380.D-0272).
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34.
  • Tsagkozis, Panagiotis, et al. (författare)
  • Intralesional margin after excision of a high-grade osteosarcoma : Is it a catastrophe?
  • 2022
  • Ingår i: Journal of Surgical Oncology. - : Wiley. - 0022-4790 .- 1096-9098. ; 126:4, s. 787-792
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and Objectives: Treatment of high-grade osteosarcoma (OS) relies on a combination of systemic chemotherapy and radical surgical excision of the tumor. Little is known on what happens in case of an irrefutably inadequate (intralesional) margin. We aimed to describe the outcome of patients with high-grade OSs of the trunk and the extremities where planned wide resection resulted in an intralesional margin. Methods: A retrospective study from the Scandinavian Sarcoma Group registry and the Royal Orthopaedic Hospital databases including data from 53 patients surgically treated between the years 1990 and 2017. Results: Local recurrence was observed in 13/53 patients. All patients with local recurrence where the neoadjuvant chemotherapy response could be retrieved (n = 9) were shown to be poor responders. None of the patients with good response to chemotherapy relapsed. Postoperative radiotherapy was not associated with improved local control of the disease. Re-excision surgery was performed in only seven patients, and two of them had tumor relapse. Conclusions: Good response to chemotherapy salvages the outcome of surgical excision with a poor margin in patients with high-grade OSs and a watchful waiting strategy may be justified in these cases. Poor responders have a higher recurrence risk and their approach should be individualized.
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35.
  • Yin, Yuqing, et al. (författare)
  • Unraveling the Bonding Complexity of Polyhalogen Anions: High-Pressure Synthesis of Unpredicted Sodium Chlorides Na2Cl3 and Na4Cl5 and Bromide Na4Br5
  • 2023
  • Ingår i: JACS Au. - : AMER CHEMICAL SOC. - 2691-3704. ; 3:6, s. 1634-1641
  • Tidskriftsartikel (refereegranskat)abstract
    • The field of polyhalogen chemistry, specifically polyhalogenanions(polyhalides), is rapidly evolving. Here, we present the synthesisof three sodium halides with unpredicted chemical compositions andstructures (tP10-Na2Cl3, hP18-Na4Cl5, and hP18-Na4Br5), a series of isostructural cubic cP8-AX(3) halides (NaCl3, KCl3, NaBr3, and KBr3), and a trigonal potassiumchloride (hP24-KCl3). The high-pressuresyntheses were realized at 41-80 GPa in diamond anvil cellslaser-heated at about 2000 K. Single-crystal synchrotron X-ray diffraction(XRD) provided the first accurate structural data for the symmetrictrichloride Cl-3 (-) anion in hP24-KCl3 and revealed the existence of two different typesof infinite linear polyhalogen chains, [Cl]( infinity ) ( n-) and [Br]( infinity ) ( n-), in the structures of cP8-AX(3) compounds and in hP18-Na4Cl5 and hP18-Na4Br5. In Na4Cl5 and Na4Br5, we found unusually short, likely pressure-stabilized, contactsbetween sodium cations. Ab initio calculations support the analysisof structures, bonding, and properties of the studied halogenides.
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