147 research outputs found
Effects of SKF-83566 and haloperidol on performance on progressive ratio schedules maintained by sucrose and corn oil reinforcement: quantitative analysis using a new model derived from the Mathematical Principles of Reinforcement (MPR)
RationaleMathematical models can assist the interpretation of the effects of interventions on schedule-controlled behaviour and help to differentiate between processes that may be confounded in traditional performance measures such as response rate and the breakpoint in progressive ratio (PR) schedules.ObjectiveThe effects of a D1-like dopamine receptor antagonist, 8-bromo-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepin-7-ol hydrobromide (SKF-83566), and a D2-like receptor antagonist, haloperidol, on rats’ performance on PR schedules maintained by sucrose and corn oil reinforcers were assessed using a new model derived from Killeen’s (Behav Brain Sci 17:105–172, 1994) Mathematical Principles of Reinforcement.MethodSeparate groups of rats were trained under a PR schedule using sucrose or corn oil reinforcers. SKF-83566 (0.015 and 0.03 mg kg−1) and haloperidol (0.05 and 0.1 mg kg−1) were administered intraperitoneally (five administrations of each treatment). Running and overall response rates in successive ratios were analysed using the new model, and estimates of the model’s parameters were compared between treatments.ResultsHaloperidol reduced a (the parameter expressing incentive value) in the case of both reinforcers, but did not affect the parameters related to response time and post-reinforcement pausing. SKF-83566 reduced a and k (the parameter expressing sensitivity of post-reinforcement pausing to the prior inter-reinforcement interval) in the case of sucrose, but did not affect any of the parameters in the case of corn oil.ConclusionsThe results are consistent with the hypothesis that blockade of both D1-like and D2-like receptors reduces the incentive value of sucrose, whereas the incentive value of corn oil is more sensitive to blockade of D2-like than D1-like receptors
Quantitative analysis of performance on a progressive-ratio schedule: effects of reinforcer type, food deprivation and acute treatment with Δ⁹-tetrahydrocannabinol (THC)
Rats’ performance on a progressive-ratio schedule maintained by sucrose (0.6 M, 50 μl) and corn oil (100%, 25 μl) reinforcers was assessed using a model derived from Killeen’s (1994) theory of scheduled-controlled behaviour, ‘Mathematical Principles of Reinforcement’. When the rats were maintained at 80% of their free-feeding body weights, the parameter expressing incentive value, a, was greater for the corn oil than for the sucrose reinforcer; the response-time parameter, δ, did not differ between the reinforcer types, but a parameter derived from the linear waiting principle (Tₒ), indicated that the minimum post-reinforcement pause was longer for corn oil than for sucrose. When the rats were maintained under free-feeding conditions, a was reduced, indicating a reduction of incentive value, but δ was unaltered. Under the food-deprived condition, the CB1 cannabinoid receptor agonist Δ⁹-tetrahydrocannabinol (THC: 0.3, 1 and 3 mg kg-1) increased the value of sucrose; none of the other parameters was affected by THC. The results provide new information about the sensitivity of the model’s parameters to deprivation and reinforcer quality, and suggest that THC selectively enhances the incentive value of sucrose
Improved constraints on the expansion rate of the Universe up to z~1.1 from the spectroscopic evolution of cosmic chronometers
We present new improved constraints on the Hubble parameter H(z) in the
redshift range 0.15 < z < 1.1, obtained from the differential spectroscopic
evolution of early-type galaxies as a function of redshift. We extract a large
sample of early-type galaxies (\sim11000) from several spectroscopic surveys,
spanning almost 8 billion years of cosmic lookback time (0.15 < z < 1.42). We
select the most massive, red elliptical galaxies, passively evolving and
without signature of ongoing star formation. Those galaxies can be used as
standard cosmic chronometers, as firstly proposed by Jimenez & Loeb (2002),
whose differential age evolution as a function of cosmic time directly probes
H(z). We analyze the 4000 {\AA} break (D4000) as a function of redshift, use
stellar population synthesis models to theoretically calibrate the dependence
of the differential age evolution on the differential D4000, and estimate the
Hubble parameter taking into account both statistical and systematical errors.
We provide 8 new measurements of H(z) (see Tab. 4), and determine its change in
H(z) to a precision of 5-12% mapping homogeneously the redshift range up to z
\sim 1.1; for the first time, we place a constraint on H(z) at z \neq 0 with a
precision comparable with the one achieved for the Hubble constant (about 5-6%
at z \sim 0.2), and covered a redshift range (0.5 < z < 0.8) which is crucial
to distinguish many different quintessence cosmologies. These measurements have
been tested to best match a \Lambda CDM model, clearly providing a
statistically robust indication that the Universe is undergoing an accelerated
expansion. This method shows the potentiality to open a new avenue in constrain
a variety of alternative cosmologies, especially when future surveys (e.g.
Euclid) will open the possibility to extend it up to z \sim 2.Comment: 34 pages, 15 figures, 6 tables, published in JCAP. It is a companion
to Moresco et al. (2012b, http://arxiv.org/abs/1201.6658) and Jimenez et al.
(2012, http://arxiv.org/abs/1201.3608). The H(z) data can be downloaded at
http://www.physics-astronomy.unibo.it/en/research/areas/astrophysics/cosmology-with-cosmic-chronometer
DIFFERENTIAL TOLERANCE OF PUMPKIN SPECIES TO BENTAZON, METRIBUZIN, TRIFLURALIN, AND OXYFLUORFEN
Fungal Planet description sheets: 1436–1477
Novel species of fungi described in this study include those from various countries as follows: Argentina, Colletotrichum araujiae on leaves, stems and fruits of Araujia hortorum. Australia, Agaricus pateritonsus on soil, Curvularia fraserae on dying leaf of Bothriochloa insculpta, Curvularia millisiae from yellowing leaf tips of Cyperus aromaticus, Marasmius brunneolorobustus on well-rotted wood, Nigrospora cooperae from necrotic leaf of Heteropogon contortus, Penicillium tealii from the body of a dead spider, Pseudocercospora robertsiorum from leaf spots of Senna tora, Talaromyces atkinsoniae from gills of Marasmius crinis-equi and Zasmidium pearceae from leaf spots of Smilax glyciphylla. Brazil, Preussia bezerrensis from air. Chile, Paraconiothyrium kelleni from the rhizosphere of Fragaria chiloensis subsp. chiloensis f. chiloensis. Finland, Inocybe udicola on soil in mixed forest with Betula pendula, Populus tremula, Picea abies and Alnus incana. France, Myrmecridium normannianum on dead culm of unidentified Poaceae. Germany, Vexillomyces fraxinicola from symptomless stem wood of Fraxinus excelsior. India, Diaporthe limoniae on infected fruit of Limonia acidissima, Didymella naikii on leaves of Cajanus cajan, and Fulvifomes mangroviensis on basal trunk of Aegiceras corniculatum. Indonesia, Penicillium ezekielii from Zea mays kernels. Namibia, Neocamarosporium calicoremae and Neocladosporium calicoremae on stems of Calicorema capitata, and Pleiochaeta adenolobi on symptomatic leaves of Adenolobus pechuelii. Netherlands, Chalara pteridii on stems of Pteridium aquilinum, Neomackenziella juncicola (incl. Neomackenziella gen. nov.) and Sporidesmiella junci from dead culms of Juncus effusus. Pakistan, Inocybe longistipitata on soil in a Quercus forest. Poland, Phytophthora viadrina from rhizosphere soil of Quercus robur, and Septoria krystynae on leaf spots of Viscum album. Portugal (Azores), Acrogenospora stellata on dead wood or bark. South Africa, Phyllactinia greyiae on leaves of Greyia sutherlandii and Punctelia anae on bark of Vachellia karroo. Spain, Anteaglonium lusitanicum on decaying wood of Prunus lusitanica subsp. lusitanica, Hawksworthiomyces riparius from fluvial sediments, Lophiostoma carabassense endophytic in roots of Limbarda crithmoides, and Tuber mohedanoi from calcareus soils. Spain (Canary Islands), Mycena laurisilvae on stumps and woody debris. Sweden, Elaphomyces geminus from soil under Quercus robur. Thailand, Lactifluus chiangraiensis on soil under Pinus merkusii, Lactifluus nakhonphanomensis and Xerocomus sisongkhramensis on soil under Dipterocarpus trees. Ukraine, Valsonectria robiniae on dead twigs of Robinia hispida. USA, Spiralomyces americanus (incl. Spiralomyces gen. nov.) from office air. Morphological and culture characteristics are supported by DNA barcodes
Plastic inducible morphologies are not always adaptive: The importance of time delays in a stochastic environment
Planck early results. II. The thermal performance of Planck
The performance of the Planck instruments in space is enabled by their low operating temperatures, 20 K for LFI and 0.1 K for HFI, achieved
through a combination of passive radiative cooling and three active mechanical coolers. The scientific requirement for very broad frequency
coverage led to two detector technologies with widely different temperature and cooling needs. Active coolers could satisfy these needs; a helium
cryostat, as used by previous cryogenic space missions (IRAS, COBE, ISO, Spitzer, AKARI), could not. Radiative cooling is provided by three
V-groove radiators and a large telescope baffle. The active coolers are a hydrogen sorption cooler (<20 K), a 4He Joule-Thomson cooler (4.7 K),
and a 3He-4He dilution cooler (1.4 K and 0.1 K). The flight system was at ambient temperature at launch and cooled in space to operating
conditions. The HFI bolometer plate reached 93 mK on 3 July 2009, 50 days after launch. The solar panel always faces the Sun, shadowing the
rest of Planck, and operates at a mean temperature of 384 K. At the other end of the spacecraft, the telescope baffle operates at 42.3 K and the
telescope primary mirror operates at 35.9 K. The temperatures of key parts of the instruments are stabilized by both active and passive methods.
Temperature fluctuations are driven by changes in the distance from the Sun, sorption cooler cycling and fluctuations in gas-liquid flow, and
fluctuations in cosmic ray flux on the dilution and bolometer plates. These fluctuations do not compromise the science data
Genome-Wide Association Study in BRCA1 Mutation Carriers Identifies Novel Loci Associated with Breast and Ovarian Cancer Risk
BRCA1-associated breast and ovarian cancer risks can be modified by common genetic variants. To identify further cancer risk-modifying loci, we performed a multi-stage GWAS of 11,705 BRCA1 carriers (of whom 5,920 were diagnosed with breast and 1,839 were diagnosed with ovarian cancer), with a further replication in an additional sample of 2,646 BRCA1 carriers. We identified a novel breast cancer risk modifier locus at 1q32 for BRCA1 carriers (rs2290854, P = 2.7×10-8, HR = 1.14, 95% CI: 1.09-1.20). In addition, we identified two novel ovarian cancer risk modifier loci: 17q21.31 (rs17631303, P = 1.4×10-8, HR = 1.27, 95% CI: 1.17-1.38) and 4q32.3 (rs4691139, P = 3.4×10-8, HR = 1.20, 95% CI: 1.17-1.38). The 4q32.3 locus was not associated with ovarian cancer risk in the general population or BRCA2 carriers, suggesting a BRCA1-specific associat
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
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