79 research outputs found
The evolution of star formation in quasar host galaxies
We have used far-infrared data from IRAS, ISO, SWIRE, SCUBA and MAMBO to
constrain statistically the mean far-infrared luminosities of quasars. Our
quasar compilation at redshifts 0<z<6.5 and I-band luminosities -20<I(AB)<-32
is the first to distinguish evolution from quasar luminosity dependence in such
a study. We carefully cross-calibrate IRAS against Spitzer and ISO, finding
evidence that IRAS 100um fluxes at <1Jy are overestimated by ~30%. We find
evidence for a correlation between star formation in quasar hosts and the
quasar optical luminosities, varying as SFR proportional to L_opt^(0.44+/-0.07)
at any fixed redshift below z=2. We also find evidence for evolution of the
mean star formation rate in quasar host galaxies, scaling as (1+z)^(1.6+/-0.3)
at z<2 for any fixed quasar I-band absolute magnitude fainter than -28. We find
no evidence for any correlation between star formation rate and black hole mass
at 0.5<z<4. Our data are consistent with feedback from black hole accretion
regulating stellar mass assembly at all redshifts.Comment: MNRAS, accepted on 22 Dec 2008. Uses BoxedEPS (included
Biodiversity and ecosystem services science for a sustainable planet: the DIVERSITAS vision for 2012–20
DIVERSITAS, the international programme on biodiversity science, is releasing a strategic vision presenting scientific challenges for the next decade of research on biodiversity and ecosystem services: “Biodiversity and Ecosystem Services Science for a Sustainable Planet”. This new vision is a response of the biodiversity and ecosystem services scientific community to the accelerating loss of the components of biodiversity, as well as to changes in the biodiversity science-policy landscape (establishment of a Biodiversity Observing Network — GEO BON, of an Intergovernmental science-policy Platform on Biodiversity and Ecosystem Services — IPBES, of the new Future Earth initiative; and release of the Strategic Plan for Biodiversity 2011–2020). This article presents the vision and its core scientific challenges.Fil: Larigauderie, Anne. DIVERSITAS. Muséum National d’Histoire Naturelle; FranciaFil: Prieur Richard, Anne Helene. DIVERSITAS. Muséum National d’Histoire Naturelle; FranciaFil: Mace, Georgina. Imperial College London. Center for Population Biology; Reino UnidoFil: Londsdale, Mark. CSIRO Ecosystem Sciences; AustraliaFil: Mooney, Harold A.. Stanford University. Department of Biological Sciences; Estados UnidosFil: Brussaard, Lijbert. Wageningen University, Soil Quality Department; Países BajosFil: Cooper, David. Secretariat of the Convention on Biological Diversity; CanadáFil: Wolfgang, Cramer. Institut Méditerranéen de Biodiversité et d’Ecologie marine et continentale; FranciaFil: Daszak, Peter. EcoHealth Alliance. Wildlife Trust; Estados UnidosFil: Diaz, Sandra Myrna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Duraiappah, Anantha. International Human Dimensions Programme; AlemaniaFil: Elmqvist, Thomas. University of Stockholm. Department of Systems Ecology and Stockholm Resilience Center; SueciaFil: Faith, Daniel. The Australian Museum; AustraliaFil: Jackson, Louise. University of California; Estados UnidosFil: Krug, Cornelia. DIVERSITAS. Muséum National d’Histoire Naturelle; FranciaFil: Leadley, Paul. Université Paris. Laboratoire Ecologie Systématique Evolution, Ecologie des Populations et Communautés; FranciaFil: Le Prestre, Philippe. Laval University; CanadáFil: Matsuda, Hiroyuki. Yokohama National University; JapónFil: Palmer, Margaret. University of Maryland; Estados UnidosFil: Perrings, Charles. Arizona State University; Estados UnidosFil: Pulleman, Mirjam. Wageningen University; Países BajosFil: Reyers, Belinda. Natural Resources and Environment; SudáfricaFil: Rosa, Eugene A.. Washington State University; Estados UnidosFil: Scholes, Robert J.. Natural Resources and Environment; SudáfricaFil: Spehn, Eva. Universidad de Basilea; SuizaFil: Turner II, B. L.. Arizona State University; Estados UnidosFil: Yahara, Tetsukazu. Kyushu University; Japó
Deriving criteria to select arthropod species for laboratory tests to assess the ecological risks from cultivating arthropod-resistant genetically engineered crops
Arthropods form a major part of the biodiversity in agricultural landscapes. Many species are valued because they provide ecosystem services, including biological control, pollination and decomposition, or because they are of conservation interest. Some arthropods reduce crop yield and quality, and conventional chemical pesticides, biological control agents and genetically engineered (GE) crops are used to control them. A common concern addressed in the ecological risk assessment (ERA) that precedes regulatory approval of these pest control methods is their potential to adversely affect valued non-target arthropods (NTAs). A key concept of ERA is early-tier testing using worst-case exposure conditions in the laboratory and surrogate test species that are most likely to reveal an adverse effect. If no adverse effects are observed in those species at high exposures, confidence of negligible ecological risk from the use of the pest control method is increased. From experience with chemical pesticides and biological control agents, an approach is proposed for selecting test species for early-tier ERA of GE arthropod-resistant crops. Surrogate species should be selected that most closely meet three criteria: (i) Potential sensitivity: species should be the most likely to be sensitive to the arthropod-active compound based on the known spectrum of activity of the active ingredient, its mode of action, and the phylogenetic relatedness of the test and target species; (ii) Relevance: species should be representative of valued taxa or functional groups that are most likely to be exposed to the arthropod-active compound in the field; and (iii) Availability and reliability: suitable life-stages of the test species must be obtainable in sufficient quantity and quality, and validated test protocols must be available that allow consistent detection of adverse effects on ecologically relevant parameters. Our proposed approach ensures that the most suitable species are selected for testing and that the resulting data provide the most rigorous test of the risk hypothesis of no adverse effect in order to increase the quality and efficiency of ERAs for cultivation of GE crops
FMR1 Genotype with Autoimmunity-Associated Polycystic Ovary-Like Phenotype and Decreased Pregnancy Chance
The FMR1 gene partially appears to control ovarian reserve, with a specific ovarian sub-genotype statistically associated with a polycystic ovary (PCO)- like phenotype. Some forms of PCO have been associated with autoimmunity. We, therefore, investigated in multiple regression analyses associations of ovary-specific FMR1 genotypes with autoimmunity and pregnancy chances (with in vitro fertilization, IVF) in 339 consecutive infertile women (455 IVF cycles), 75 with PCO-like phenotype, adjusted for age, race/ethnicity, medication dosage and number of oocytes retrieved. Patients included 183 (54.0%) with normal (norm) and 156 (46%) with heterozygous (het) FMR1 genotypes; 133 (39.2%) demonstrated laboratory evidence of autoimmunity: 51.1% of het-norm/low, 38.3% of norm and 24.2% het-norm/high genotype and sub-genotypes demonstrated autoimmunity (p = 0.003). Prevalence of autoimmunity increased further in PCO-like phenotype patients with het-norm/low genotype (83.3%), remained unchanged with norm (34.0%) and decreased in het-norm/high women (10.0%; P<0.0001). Pregnancy rates were significantly higher with norm (38.6%) than het-norm/low (22.2%, p = 0.001). FMR1 sub-genotype het-norm/low is strongly associated with autoimmunity and decreased pregnancy chances in IVF, reaffirming the importance of the distal long arm of the X chromosome (FMR1 maps at Xq27.3) for autoimmunity, ovarian function and, likely, pregnancy chance with IVF
Phylogeography of Supralittoral Rocky Intertidal Ligia Isopods in the Pacific Region from Central California to Central Mexico
Ligia isopods are widely distributed in the Pacific rocky intertidal shores from central California to central Mexico, including the Gulf of California. Yet, their biological characteristics restrict them to complete their life cycles in a very narrow range of the rocky intertidal supralittoral. Herein, we examine phylogeographic patterns of Ligia isopods from 122 localities between central California and central Mexico. We expect to find high levels of allopatric diversity. In addition, we expect the phylogeographic patterns to show signatures of past vicariant events that occurred in this geologically dynamic region.We sequenced two mitochondrial genes (Cytochrome Oxidase I and 16S ribosomal DNA). We conducted Maximum Likelihood and Bayesian phylogenetic analyses. We found many divergent clades that, in general, group according to geography. Some of the most striking features of the Ligia phylogeographic pattern include: (1) deep mid-peninsular phylogeographic breaks on the Pacific and Gulf sides of Baja peninsula; (2) within the Gulf lineages, the northern peninsula is most closely related to the northern mainland, while the southern peninsula is most closely related to the central-southern mainland; and, (3) the southernmost portion of the peninsula (Cape Region) is most closely related to the southernmost portion of mainland.Our results shed light on the phylogenetic relationships of Ligia populations in the study area. This study probably represents the finest-scale phylogeographic examination for any organism to date in this region. Presence of highly divergent lineages suggests multiple Ligia species exist in this region. The phylogeographic patterns of Ligia in the Gulf of California and Baja peninsula are incongruent with a widely accepted vicariant scenario among phylogeographers, but consistent with aspects of alternative geological hypotheses and phylo- and biogeographic patterns of several other taxa. Our findings contribute to the ongoing debate regarding the geological origin of this important biogeographic region
4D-Var inversion of European NH3 emissions Using CrIS NH3 measurements and GEOS-Chem adjoint with bi-directional and uni-directional flux schemes
We conduct the first 4D-Var inversion of NH3 accounting for NH3 bi-directional flux, using CrIS satellite NH3 observations over Europe in 2016. We find posterior NH3 emissions peak more in springtime than prior emissions at continental to national scales, and annually they are generally smaller than the prior emissions over central Europe, but larger over most of the rest of Europe. Annual posterior anthropogenic NH3 emissions for 25 European Union members (EU25) are 25% higher than the prior emissions and very close (<2% difference) to other inventories. Our posterior annual anthropogenic emissions for EU25, the UK, the Netherlands, and Switzerland are generally 10%–20% smaller than when treating NH3 fluxes as uni-directional emissions, while the monthly regional difference can be up to 34% (Switzerland in July). Compared to monthly mean in-situ observations, our posterior NH3 emissions from both schemes generally improve the magnitude and seasonality of simulated surface NH3 and bulk NHx wet deposition throughout most of Europe, whereas evaluation against hourly measurements at a background site shows the bi-directional scheme better captures observed diurnal variability of surface NH3. This contrast highlights the need for accurately simulating diurnal variability of NH3 in assimilation of sun-synchronous observations and also the potential value of future geostationary satellite observations. Overall, our top-down ammonia emissions can help to examine the effectiveness of air pollution control policies to facilitate future air pollution management, as well as helping us understand the uncertainty in top-down NH3 emissions estimates associated with treatment of NH3 surface exchange
Disturbance as a factor in breaking dormancy and enhancing invasiveness of African grasses in a Neotropical Savanna
The Role of Plants in the Effects of Global Change on Nutrient Availability and Stoichiometry in the Plant-Soil System
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