Inferential Item-Fit Evaluation in Cognitive Diagnosis Modeling

Research related to the fit evaluation at the item level involving cognitive diagnosis models (CDMs) has been scarce. According to the parsimony principle, balancing goodness of fit against model complexity is necessary. General CDMs require a larger sample size to be estimated reliably, and can lead to worse attribute classification accuracy than the appropriate reduced models when the sample size is small and the item quality is poor, which is typically the case in many empirical applications. The main purpose of this study was to systematically examine the statistical properties of four inferential item-fit statistics: S-X2, the likelihood ratio (LR) test, the Wald (W) test, and the Lagrange multiplier (LM) test. To evaluate the performance of the statistics, a comprehensive set of factors, namely, sample size, correlational structure, test length, item quality, and generating model, is systematically manipulated using Monte Carlo methods. Results show that the S-X2 statistic has unacceptable power. Type I error and power comparisons favor LR and W tests over the LM test. However, all the statistics are highly affected by the item quality. With a few exceptions, their performance is only acceptable when the item quality is high. In some cases, this effect can be ameliorated by an increase in sample size and test length. This implies that using the above statistics to assess item fit in practical settings when the item quality is low remains a challenge

Critical revision of some Myxomycetes deposited in the Buenos Aires HerbariaBAFC, BA and the Tucuman Herbarium LIL. IV

Fifty-seven collections preserved in herbaria BAFC, BA; LIL and Ah representing 26 different species of Myxomycetes are included in this paper. Five species, Comatricha ellae, Didymium megalosporum, Lycogala exiguum, Physarum flavicomum and P. stellatum, are new records from Argentina. Microphotograhs using both optical (LM) and scanning electron microscopy (SEM) are included. these photographs illustrate the most representative characteristics of those species which are rare or not mentioned in Argentina before this work.Cincuenta y siete colecciones conservadas en los herbarios BAFC, BA LIL y AH se incluyen en este trabajo que representan 26 especies diferentes de Myxomycetes. Cinco especies, Comatricha ellae, Didymium megalosporum, Lycogala exiguum, Physarum flavicomum y P. stellatum, son nuevas citas para Argentina. Microfotografias de microscopía óptica y microscopía electrónica de barrido son incluidas. Estas fotografías ilustran las características más representativas de las especies que son raras o no citadas en Argentina

Схиигумен Сергий как маргинальная языковая личность в пространстве религиозно-политической коммуникации

SummaryThaumarchaeota are globally distributed and abundantmicroorganisms occurring in diverse habitats and thusrepresent a major source of archaeal lipids. The scopeof lipids as taxonomic markers in microbial ecologicalstudies is limited by the scarcity of comparative dataon the membrane lipid composition of cultivated representatives,including the phylum Thaumarchaeota.Here, we comprehensively describe the core and intactpolar lipid (IPL) inventory of ten ammonia-oxidisingthaumarchaeal cultures representing all four characterizedphylogenetic clades. IPLs of these thaumarchaealstrains are generally similar and consist of membranespanning,glycerol dibiphytanyl glycerol tetraetherswith monoglycosyl, diglycosyl, phosphohexose andhexose-phosphohexose headgroups. However, the relativeabundances of these IPLs and their core lipidcompositions differ systematically between the phylogeneticsubgroups, indicating high potential forchemotaxonomic distinction of thaumarchaeal clades.Comparative lipidomic analyses of 19 euryarchaeal andcrenarchaeal strains suggested that the lipid methoxyarchaeol is synthesized exclusively by Thaumarchaeotaand may thus represent a diagnostic lipidbiomarker for this phylum. The unprecedented diversityof the thaumarchaeal lipidome with 118 differentlipids suggests that membrane lipid composition andadaptation mechanisms in Thaumarchaeota are morecomplex than previously thought and include uniquelipids with as yet unresolved properties

Dust Lifting Through Surface Albedo Changes at Jezero Crater, Mars

We identify temporal variations in surface albedo at Jezero crater using first-of-their-kind high-cadence in-situ measurements of reflected shortwave radiation during the first 350 sols of the Mars 2020 mission. Simultaneous Mars Environmental Dynamics Analyzer (MEDA) measurements of pressure, radiative fluxes, winds, and sky brightness indicate that these albedo changes are caused by dust devils under typical conditions and by a dust storm at Ls ∼ 155°. The 17% decrease in albedo caused by the dust storm is one order of magnitude larger than the most apparent changes caused during quiescent periods by dust devils. Spectral reflectance measurements from Mastcam-Z images before and after the storm indicate that the decrease in albedo is mainly caused by dust removal. The occurrence of albedo changes is affected by the intensity and proximity of the convective vortex, and the availability and mobility of small particles at the surface. The probability of observing an albedo change increases with the magnitude of the pressure drop (ΔP): changes were detected in 3.5%, 43%, and 100% of the dust devils with ΔP 2.5 Pa and ΔP > 4.5 Pa, respectively. Albedo changes were associated with peak wind speeds above 15 m·s−1. We discuss dust removal estimates, the observed surface temperature changes coincident with albedo changes, and implications for solar-powered missions. These results show synergies between multiple instruments (MEDA, Mastcam-Z, Navcam, and the Supercam microphone) that improve our understanding of aeolian processes on Mars.This research has been funded by the Comunidad de Madrid Project S2018/NMT-4291 (TEC2SPACE-CM), by the Spanish State Research Agency (AEI) Project MDM-2017-0737 Unidad de Excelencia “María de Maeztu”- Centro de Astrobiología (CSIC/INTA), by the Spanish Ministry of Science and Innovation (MCIN)/State Agency of Research (10.13039/501100011033) project RTI2018-098728-B-C31, and by the project PID2021-126719OB-C41, funded by MCIN/AEI/10.13039/501100011033/FEDER, UE. RH, ASL and AM were supported by Grant PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/501100011033/. Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). We want to thank J. Bell for processing Mastcam-Z projections showing the entire TIRS FOV and to S. Navarro and the entire team for generating the processed wind sensor data

Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02