668 research outputs found
C3âC4 composition and prior carbon dioxide treatment regulate the response of grassland carbon and water fluxes to carbon dioxide
During May, July and October 2000, we measured the effects of temporarily increasing or decreasing CO2 concentration by 150â200 ÎŒmol molâ1 on daytime net ecosystem CO2 exchange (NEE) and water flux (evapotranspiration, ET) of C3âC4 grassland in central Texas, USA that had been exposed for three growing seasons to a CO2 gradient from 200 to 560 ÎŒmol molâ1. Grassland grown at subambient CO2 (\u3c 365 ÎŒmol molâ1) was exposed for 2 days to an elevated CO2 gradient (\u3e 365 ÎŒmol molâ1). Grassland grown at elevated CO2 was exposed for 2 days to a subambient gradient. Our objective was to determine whether growth CO2 affected the amount by which grassland NEE and ET responded to CO2 switching (sensitivity to CO2)
Torsion pairs and simple-minded systems in triangulated categories
Let T be a Hom-finite triangulated Krull-Schmidt category over a field k.
Inspired by a definition of Koenig and Liu, we say that a family S of pairwise
orthogonal objects in T with trivial endomorphism rings is a simple-minded
system if its closure under extensions is all of T. We construct torsion pairs
in T associated to any subset X of a simple-minded system S, and use these to
define left and right mutations of S relative to X. When T has a Serre functor
\nu, and S and X are invariant under \nu[1], we show that these mutations are
again simple-minded systems. We are particularly interested in the case where T
is the stable module category of a self-injective algebra \Lambda. In this
case, our mutation procedure parallels that introduced by Koenig and Yang for
simple-minded collections in the derived category of \Lambda. It follows that
the mutation of the set of simple \Lambda-modules relative to X yields the
images of the simple \Gamma-modules under a stable equivalence between \Gamma\
and \Lambda, where \Gamma\ is the tilting mutation of \Lambda\ relative to X.Comment: Minor corrections. To appear in Applied Categorical Structures. The
final publication is available at springerlink.com:
http://link.springer.com/article/10.1007%2Fs10485-014-9365-
Performance of the inFLUenza Patient-Reported Outcome (FLU-PRO) diary in patients with influenza-like illness (ILI)
BACKGROUND: The inFLUenza Patient Reported Outcome (FLU-PRO) measure is a daily diary assessing signs/symptoms of influenza across six body systems: Nose, Throat, Eyes, Chest/Respiratory, Gastrointestinal, Body/Systemic, developed and tested in adults with influenza. OBJECTIVES: This study tested the reliability, validity, and responsiveness of FLU-PRO scores in adults with influenza-like illness (ILI). METHODS: Data from the prospective, observational study used to develop and test the FLU-PRO in influenza virus positive patients were analyzed. Adults (â„18 years) presenting with influenza symptoms in outpatient settings in the US, UK, Mexico, and South America were enrolled, tested for influenza virus, and asked to complete the 37-item draft FLU-PRO daily for up to 14-days. Analyses were performed on data from patients testing negative. Reliability of the final, 32-item FLU-PRO was estimated using Cronbach's alpha (α; Day 1) and intraclass correlation coefficients (ICC; 2-day reproducibility). Convergent and known-groups validity were assessed using patient global assessments of influenza severity (PGA). Patient report of return to usual health was used to assess responsiveness (Day 1-7). RESULTS: The analytical sample included 220 ILI patients (mean age = 39.3, 64.1% female, 88.6% white). Sixty-one (28%) were hospitalized at some point in their illness. Internal consistency reliability (α) of FLU-PRO Total score was 0.90 and ranged from 0.72-0.86 for domain scores. Reproducibility (Day 1-2) was 0.64 for Total, ranging from 0.46-0.78 for domain scores. Day 1 FLU-PRO scores correlated (â„0.30) with the PGA (except Gastrointestinal) and were significantly different across PGA severity groups (Total: F = 81.7, p<0.001; subscales: F = 6.9-62.2; p<0.01). Mean score improvements Day 1-7 were significantly greater in patients reporting return to usual health compared with those who did not (p<0.05, Total and subscales, except Gastrointestinal and Eyes). CONCLUSIONS: Results suggest FLU-PRO scores are reliable, valid, and responsive in adults with influenza-like illness
Net grassland carbon flux over a subambient to superambient CO2 gradient
Increasing atmospheric CO2 concentrations may have a profound effect on the structure and function of plant communities. A previously grazed, central Texas grassland was exposed to a 200-”mol mol-1 to 550 ”mol mol-1 CO2 gradient from March to mid-December in 1998 and 1999 using two, 60-m long, polyethylene-covered chambers built directly onto the site. One chamber was operated at subambient CO2 concentrations (200-360 ”mol mol-1 daytime) and the other was regulated at superambient concentrations (360-550 ”mol mol-1). Continuous CO2 gradients were maintained in each chamber by photosynthesis during the day and respiration at night. Net ecosystem CO2 flux and end-of-year biomass were measured in each of 10, 5-m long sections in each chamber. Net CO2 fluxes were maximal in late May (c. day 150) in 1998 and in late August in 1999 (c. day 240). In both years, fluxes were near zero and similar in both chambers at the beginning and end of the growing season. Average daily CO2 flux in 1998 was 13 g CO2 m-2 day-1 in the subambient chamber and 20 g CO2 m-2 day-1 in the superambient chamber; comparable averages were 15 and 26 g CO2 m-2 day-1 in 1999. Flux was positively and linearly correlated with end-of-year above-ground biomass but flux was not linearly correlated with CO2 concentration; a finding likely to be explained by inherent differences in vegetation. Because C3 plants were the dominant functional group, we adjusted average daily flux in each section by dividing the flux by the average percentage C3 cover. Adjusted fluxes were better correlated with CO2 concentration, although scatter remained. Our results indicate that after accounting for vegetation differences, CO2 flux increased linearly with CO2 concentration. This trend was more evident at subambient than superambient CO2 concentrations
Colouration in amphibians as a reflection of nutritional status : the case of tree frogs in Costa Rica
Colouration has been considered a cue for mating success in many species; ornaments in males often are related to carotenoid mobilization towards feathers and/or skin and can signal general health and nutrition status. However, there are several factors that can also link with status, such as physiological blood parameters and body condition, but there is not substantial evidence which supports the existence of these relationships and interactions in anurans. This study evaluated how body score and blood values interact with colouration in free-range Agalychnis callidryas and Agalychnis annae males. We found significant associations between body condition and plasmatic proteins and haematocrit, as well as between body condition and colour values from the chromaticity diagram. We also demonstrated that there is a significant relation between the glucose and plasmatic protein values that were reflected in the ventral colours of the animals, and haematocrit inversely affected most of those colour values. Significant differences were found between species as well as between populations of A. callidryas, suggesting that despite colour variation, there are also biochemical differences within animals from the same species located in different regions. These data provide information on underlying factors for colouration of male tree frogs in nature, provide insights about the dynamics of several nutrients in the amphibian model and how this could affect the reproductive output of the animals
The Shadows of the Past
We examined associations between two orientations based on historical group trauma, a form of enduring group victimhood (Perpetual Ingroup Victimhood Orientation [PIVO]) and the belief that oneâs group might itself become a victimizer (Fear of Victimizing [FOV]), and attitudes, cognitions, and emotions related to intergroup conflicts. PIVO was positively and FOV was negatively related to aggressive attitudes and emotions toward the outgroup (Studies 1a-1c, IsraeliâPalestinian conflict), and to the attribution of responsibility for a series of hostilities to the outgroup (Study 3, IsraeliâPalestinian conflict). PIVO was negatively and FOV positively related to support for forgiveness and reconciliation (Study 2, Northern Ireland conflict). In Experimental Study 4, FOV predicted greater accuracy in remembering harm, regardless of victimsâ group identity, whereas PIVO was associated with reduced accuracy only when victims were Palestinians (outgroup members). Taken together, these findings indicate that both orientations have a significant impact on intergroup conflicts and their resolution
The Hydrogen-Poor Superluminous Supernovae from the Zwicky Transient Facility Phase-I Survey: I. Light Curves and Measurements
During the Zwicky Transient Facility (ZTF) Phase-I operation, 78
hydrogen-poor superluminous supernovae (SLSNe-I) were discovered in less than
three years, making up the largest sample from a single survey. This paper
(Paper I) presents the data, including the optical/ultraviolet light curves and
classification spectra, while Paper II in this series will focus on the
detailed analysis of the light curves and modeling. Our photometry is primarily
taken by the ZTF in the bands, and with additional data from other
ground-based facilities and Swift. The events of our sample cover a redshift
range of , with a median and error (16\% and 84\%
percentiles) . The peak luminosity
covers \,mag, with a median
value of \,mag. Their light curves evolve slowly with
the mean rest-frame rise time of \,days. The
luminosity and time scale distributions suggest that low luminosity SLSNe-I
with peak luminosity \,mag or extremely fast rising events
(\,days) exist but are rare. We confirm previous findings that slowly
rising SLSNe-I also tend to fade slowly. The rest-frame color and temperature
evolution show large scatters, suggesting that the SLSN-I population may have
diverse spectral energy distributions. The peak rest-frame color shows a
moderate correlation with the peak absolute magnitude, i.e. brighter SLSNe-I
tend to have bluer colors. With optical and ultraviolet photometry, we
construct bolometric luminosity and derive a bolometric correction relation
generally applicable for converting -band photometry to bolometric
luminosity for SLSNe-I.Comment: 38 pages, 25 figures, Accepted by AP
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