641 research outputs found
Response to Guttman & Levy's article âon the definition and varieties of attitude and wellbeingâ
Guttman and Levy have prepared an extravagant critique focused mainly on the 1980 Andrews-McKennell article in this journal. The clearly stated purpose of that article was to report a âseries of explorations into the affective and cognitive components of some of the more widely used measures of perceived well-beingâ. Guttman and Levy ignore this. They proceed on the mistaken impression that we were (or perhaps should have been) embarking upon a definitional exercise to relate the concepts of attitude and wellbeing. Yet the reason we did not cite their article on that topic was precisely because it did not address in a direct or focused way the topic that concerned us. Their critique consists of an entirely irrelevant reanalysis of some attitudinal data by Ostrom, together with a tissue of recondite definitional and methodological issues of little consequence either for the objectives or the conclusions of our research. Their dismissal of our work as âscientific retrogressionâ rests on an a priori definition of science that fits their own methodological style but excludes that of many other prominent researchers. Their comments reflect an attempt at methodological imperialism. We defend our independence â and that of other investigators â to use promising new methodologies other than the particular approach advocated by Guttman and Levy. (Their denunciation of the new methods of structural equation modeling is not shared even by the authoritative reviewer they themselves quote.) In addition to Guttman and Levy's specific criticisms, our Response addresses general methodological issues such as the status of structural modeling and the testing of structural models. In a concluding section we identify areas that merit further research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43680/1/11205_2004_Article_BF00302509.pd
Models of cognition and affect in perceptions of well-being
How do people arrive at assessments of their own life quality? A series of models was developed to provide an interpretation of the way the factors of cognition and affect operate along with evaluations of specific life concerns (domains) in the perception of well-being. Following previous research, cognition was defined operationally as a factor which accounts for the covariance among a set of assessments of life-as-a-whole after affect, as measured by Bradburn's scales, is partialled out and after allowance is made for the presence of correlated measurement errors. It was found that loadings on the cognitive factor, and hence the interpretation of this factor, changed little despite quite large changes in the models. Moreover, in all major comparisons, models that contained the cognitive factor fitted the data better than models that did not. Models that included affect as the only variable intervening between the domains and the life-as-a-whole factor led to results that were intuitively difficult to accept. In the preferred model both affect and cognition were positioned as intervening variables. In this model it was found that the domain evaluations had no direct impact on life-as-a-whole assessments â the contribution of the domains was indirect by way of their association with cognition and affect. It was hypothesised that associated with each domain was a domain-specific element of affect and a domain-specific element of cognition. The linear additive relation found by previous researchers between domain evaluations and life-as-a-whole assessments would then be explainable as a statistical result arising from the summing of the domain-specific elements of affect and cognition.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43703/1/11205_2004_Article_BF00292640.pd
Observational diagnostics of gas in protoplanetary disks
Protoplanetary disks are composed primarily of gas (99% of the mass).
Nevertheless, relatively few observational constraints exist for the gas in
disks. In this review, I discuss several observational diagnostics in the UV,
optical, near-IR, mid-IR, and (sub)-mm wavelengths that have been employed to
study the gas in the disks of young stellar objects. I concentrate in
diagnostics that probe the inner 20 AU of the disk, the region where planets
are expected to form. I discuss the potential and limitations of each gas
tracer and present prospects for future research.Comment: Review written for the proceedings of the conference "Origin and
Evolution of Planets 2008", Ascona, Switzerland, June 29 - July 4, 2008. Date
manuscript: October 2008. 17 Pages, 6 graphics, 134 reference
A systematic review of the effects of exercise interventions on body composition in HIV+ adults
Over the years, physical activity and exercise have been used to positively impact the health and quality of life of persons infected with HIV and, more recently, has been associated with a spectrum of body composition changes. The aim of this review was to examine the effects of various exercise interventions on body composition in HIV positive adults, using a search strategy of randomized, controlled trials (RCTs). A systematic review was performed by five independent reviewers using a predetermined protocol adapted from previous research for assessing the articles for inclusion, the extracted data, and methodological quality. Eight RCTs involving 430 (26% female) HIV positive adults performing exercise a minimum of thrice weekly for at least six weeks were finally selected: Four were progressive resistance training (PRT) studies, three were aerobic training (AT) studies, and one involved yoga. In the PRT studies, there were significant increases in three anthropometric measures, namely, body mass, sum of skinfolds and sum of limb girths. In the AT studies, significant decreases were found in seven anthropometric measures, namely, body mass index, waist-hip ratio, body mass, triceps skinfold, waist circumference and sum of skinfolds. With yoga, the changes were nonsignificant. Exercise contributes to improved body composition and, when applied safely, appears to be beneficial for adults living with HIV/AIDS. However, these findings should be interpreted cautiously due to the relatively few RCTs published to date. Future studies would benefit from increased attention to sample size, female participants, participant follow-up, complete statistical analysis and intention-to-treat analysis.Scopu
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 the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV
The Lambda(b) differential production cross section and the cross section
ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum
pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7
TeV using data collected by the CMS experiment at the LHC. The measurements are
based on Lambda(b) decays reconstructed in the exclusive final state J/Psi
Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and
Lambda to proton pion, using a data sample corresponding to an integrated
luminosity of 1.9 inverse femtobarns. The product of the cross section times
the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls
faster than that of b mesons. The measured value of the cross section times the
branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06
+/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for
anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are
statistical and systematic, respectively.Comment: Submitted to Physics Letters
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