3,974 research outputs found
Julia M. Brown to James (9 October 1962)
https://egrove.olemiss.edu/mercorr_pro/2076/thumbnail.jp
Some partitions in Figueroa planes
Using Grundhƶfer'sĀ construction of the Figueroa planes from Pappian planesĀ Ā whichĀ Ā have an order planar collineation , we show that anyĀ Ā Figueroa plane (finite or infinite) has a partition of the complement of any proper ()-invariant triangle mostly into subplanes together with a fewĀ Ā collinearĀ Ā point sets (from the point set view) and a few concurrent line sets (from theĀ Ā line setĀ Ā view). Ā The partition shows that each Figueroa line (regarded as a set ofĀ Ā points) isĀ Ā either the same as a Pappian line or consists mostly of a disjoint union ofĀ Ā subplanes of the Pappian plane (most lines are of this latter type) anddually. This last sentence is true with "Figueroa" and "Pappian" interchanged. There are many collinear subsets of Figueroa points which are a subset of the set of points of a Pappian conic and dually
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A solution NMR approach to determine the chemical structures of carbohydrates using the hydroxyl groups as starting points
An efficient NMR approach is described for determining the chemical structures of the monosaccharide glucose and four disaccharides, namely, nigerose, gentiobiose, leucrose and isomaltulose. This approach uses the 1H resonances of the āOH groups, which are observable in the NMR spectrum of a supercooled aqueous solution, as the starting point for further analysis. The 2D-NMR technique, HSQC-TOCSY, is then applied to fully define the covalent structure (i.e., the topological relationship between CāC, CāH, and OāH bonds) that must be established for a novel carbohydrate before proceeding to further conformational studies. This process also leads to complete assignment of all 1H and 13C resonances. The approach is exemplified by analyzing the monosaccharide glucose, which is treated as if it were an āunknownā, and also by fully assigning all the NMR resonances for the four disaccharides that contain glucose. It is proposed that this technique should be equally applicable to the determination of chemical structures for larger carbohydrates of unknown composition, including those that are only available in limited quantities from biological studies. The advantages of commencing the structure elucidation of a carbohydrate at the āOH groups are discussed with reference to the now well-established 2D-/3D-NMR strategy for investigation of peptides/proteins, which employs the āNH resonances as the starting point
Symmetries,Singularities and the De-Emergence of Space
Recent work has revealed intriguing connections between a
Belinsky-Khalatnikov-Lifshitz-type analysis of spacelike singularities in
General Relativity and certain infinite dimensional Lie algebras, and in
particular the `maximally extended' hyperbolic Kac--Moody algebra E10. In this
essay we argue that these results may lead to an entirely new understanding of
the (quantum) nature of space(-time) at the Planck scale, and hence -- via an
effective `de-emergence' of space near a singularity -- to a novel mechanism
for achieving background independence in quantum gravity.Comment: 10 page
Correction to:Easy as (Happiness) Pie? A Critical Evaluation of a Popular Model of the Determinants of Well-Being (Journal of Happiness Studies, (2020), 21, 4, (1285-1301), 10.1007/s10902-019-00128-4)
In the original publication, the text (line 10) under the heading ā3 Reāexamining the Numerical Estimates of the Effect of Genes and Circumstancesā with sub heading ā3.1 How Much Variance in Chronic Happiness Levels can be Explained by Genetic Factors?ā has been published incorrectly
Easy as (Happiness) Pie? A Critical Evaluation of a Popular Model of the Determinants of Well-Being
An underlying principle behind much of the research in positive psychology is that individuals have considerable leeway to increase their levels of happiness. In an influential article that is frequently cited in support of such claims, Lyubomirsky et al. (Rev Gen Psychol 9:111ā131, 2005. https://doi.org/10.1037/1089-2680.9.2.111) put forward a model (subsequently popularized under the name of the āhappiness pieā) in which approximately 50% of individual differences in happiness are due to genetic factors and 10% to life circumstances, leaving 40% available to be changed via volitional activities. We re-examined Lyubomirsky et al.ās claims and found several apparent deficiencies in their chain of arguments on both the empirical and the conceptual level. We conclude that there is little empirical evidence for the variance decomposition suggested by the āhappiness pie,ā and that even if it were valid, it is not necessarily informative with respect to the question of whether individuals can truly exert substantial influence over their own chronic happiness level. We believe that our critical re-examination of Lyubomirsky et al.ās seminal article offers insights into some common misconceptions and pitfalls of scientific inference, and we hope that it might contribute to the construction of a more rigorous and solid empirical basis for the field of positive psychology
Exploring the role of pain as an early predictor of category 2 pressure ulcers: a prospective cohort study
Objective To explore pressure area related pain as a predictor of category ā„2 pressure ulcer (PU) development.
Design Multicentre prospective cohort study.
Setting UK hospital and community settings.
Participants inclusion Consenting acutely ill patients aged ā„18ā
years, defined as high risk (Braden bedfast/chairfast AND completely immobile/very limited mobility; pressure area related pain or; category 1 PU).
Exclusion Patients too unwell, unable to report pain, 2 or more category ā„2 PUs.
Follow-up Twice weekly for 30ā
days.
Primary and secondary outcome measures Development and time to development of one or more category ā„2 PUs.
Results Of 3819 screened, 1266 were eligible, 634 patients were recruited, 32 lost to follow-up, providing a 602 analysis population. 152 (25.2%) developed one or more category ā„2 PUs. 464 (77.1%) patients reported pressure area related pain on a healthy, altered or category 1 skin site of whom 130 (28.0%) developed a category ā„2 PU compared with 22 (15.9%) of those without pain. Full stepwise variable selection was used throughout the analyses. (1) Multivariable logistic regression model to assess 9 a priori factors: presence of category 1 PU (OR=3.25, 95% CI (2.17 to 4.86), p<0.0001), alterations to intact skin (OR=1.98, 95% CI (1.30 to 3.00), p=0.0014), pressure area related pain (OR=1.56, 95% CI (0.93 to 2.63), p=0.0931). (2) Multivariable logistic regression model to account for overdispersion: presence of category 1 PU (OR=3.20, 95% CI (2.11 to 4.85), p<0.0001), alterations to intact skin (OR=1.90, 95% CI (1.24 to 2.91), p=0.0032), pressure area related pain (OR=1.85, 95% CI (1.07 to 3.20), p=0.0271), pre-existing category 2 PU (OR=2.09, 95% CI (1.35 to 3.23), p=0.0009), presence of chronic wound (OR=1.66, 95% CI (1.06 to 2.62), p=0.0277), Braden activity (p=0.0476). (3) Accelerated failure time model: presence of category 1 PU (AF=2.32, 95% CI (1.73 to 3.12), p<0.0001), pressure area related pain (AF=2.28, 95% CI (1.59 to 3.27), p<0.0001). (4) 2-level random-intercept logistic regression model: skin status which comprised 2 levels (versus healthy skin); alterations to intact skin (OR=4.65, 95% CI (3.01 to 7.18), p<0.0001), presence of category 1 PU (OR=17.30, 95% CI (11.09 to 27.00), p<0.0001) and pressure area related pain (OR=2.25, 95% CI (1.53 to 3.29), p<0.0001).
Conclusions This is the first study to assess pain as a predictor of category ā„2 PU development. In all 4 models, pain emerged as a risk factor associated with an increased probability of category ā„2 PU development
The homeodomain protein PAL-1 specifies a lineage-specific regulatory network in the C. elegans embryo
Maternal and zygotic activities of the homeodomain protein PAL-1 specify the identity and maintain the development of the multipotent C blastomere lineage in the C. elegans embryo. To identify PAL-1 regulatory target genes, we used microarrays to compare transcript abundance in wild-type embryos with mutant embryos lacking a C blastomere and to mutant embryos with extra C blastomeres. pal-1-dependent C-lineage expression was verified for select candidate target genes by reporter gene analysis, though many of the target genes are expressed in additional lineages as well. The set of validated target genes includes 12 transcription factors, an uncharacterized wingless ligand and five uncharacterized genes. Phenotypic analysis demonstrates that the identified PAL-1 target genes affect specification, differentiation and morphogenesis of C-lineage cells. In particular, we show that cell fate-specific genes (or tissue identity genes) and a posterior HOX gene are activated in lineage-specific fashion. Transcription of targets is initiated in four temporal phases, which together with their spatial expression patterns leads to a model of the regulatory network specified by PAL-1
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