Symmetry Breaking, Duality and Fine-Tuning in Hierarchical Spin Models

We discuss three questions related to the critical behavior of hierarchical spin models: 1) the hyperscaling relations in the broken symmetry phase; 2) the combined use of dual expansions to calculate the non-universal quantities; 3) the fine-tuning issue in approximately supersymmetric models.Comment: 3 pages, 1 figure, Lattice99 (spin

Penetration of human skin by the cercariae of Schistosoma mansoni : an investigation of the effect of multiple cercarial applications

It has previously been postulated that L-arginine emitted by penetrating Schistosoma mansoni cercariae serves as an intraspecific signal guiding other cercariae to the penetration site. It was suggested that penetrating in groups offers a selective advantage. If this hypothesis is correct and group penetration at one site on the host offers an advantage, it would follow that at such a site, successive groups of cercariae would be able to penetrate skin in either greater numbers or at a faster rate. This prediction was tested by the use of an in vitro model of cercarial penetration based on the Franz cell and using human skin. It was demonstrated that there was no increase in the percentage of cercariae able to penetrate the skin with subsequent exposures. Consequently, it seems unlikely that the release of L-arginine by cercariae during penetration could have evolved as a specific orientation system based on a selective advantage offered by group penetration.Peer reviewe

A More Improved Lattice Action for Heavy Quarks

We extend the Fermilab formalism for heavy quarks to develop a more improved action. We give results of matching calculations of the improvement couplings at tree level. Finally, we estimate the discretization errors associated with the new action.Comment: 3 pages, 1 figure, Lattice 2003 Tsukuba Japa

Universality, Scaling and Triviality in a Hierarchical Field Theory

Using polynomial truncations of the Fourier transform of the RG transformation of Dyson's hierarchical model, we show that it is possible to calculate very accurately the renormalized quantities in the symmetric phase. Numerical results regarding the corrections to the scaling laws, (i.e finite cut-off dependence) triviality, hyperscaling, universality and high-accuracy determinations of the critical exponents are discussed.Comment: LATTICE98(spin

On the spatial Markov property of soups of unoriented and oriented loops

We describe simple properties of some soups of unoriented Markov loops and of some soups of oriented Markov loops that can be interpreted as a spatial Markov property of these loop-soups. This property of the latter soup is related to well-known features of the uniform spanning trees (such as Wilson's algorithm) while the Markov property of the former soup is related to the Gaussian Free Field and to identities used in the foundational papers of Symanzik, Nelson, and of Brydges, Fr\"ohlich and Spencer or Dynkin, or more recently by Le Jan

Reading and reflecting on experiential accounts of hospital patients to foster a person-centered care approach: A novel educational method

Background Innovative teaching methods are needed to ensure end-of-life care is provided by nurses through a person-centered approach. Aims This study was designed to (a) explore the self-identified impact of reading dying patient experiential narrative accounts on undergraduate nursing students; and (b) explore the teaching usefulness of patient experiential narrative accounts for enhanced undergraduate nursing student awareness of the need to provide person-centered end-of-life care. Methods Qualitative descriptive study, with 31 undergraduate nursing students reading experiential narrative accounts of dying patients and reflecting on them. A thematic analysis was carried out on the written student reflections. Descriptive statistics were used to summarize student socio-demographic data and their answers to questions on a reaction response sheet designed to assess how useful this activity had been from their perspective. Findings Three main themes were identified: (1) gaining an insightful understanding of the relationship between the nurse and the person with advanced-terminal illness; (2) gaining awareness of themselves as nurses in their clinical practice; (3) pointing out how nurses should behave and what they should do to place the person living with advanced-terminal illness at the center of nursing practice. Among all respondents, 87.09% of students thought this was a useful learning activity. Conclusions Reflecting on patient experiential accounts is an innovative teaching method, which help with nursing students value and gain insight into person-centered end-of-life care

Fragility of randomized trials supporting cancer drug approvals stratified by approval pathway and review designations

Background: It has been suggested that the results from fragile trials are less likely to translate into benefit in routine clinical practice. Methods: We searched the Food and Drug Administration (FDA) archives to identify drug approvals for solid organ malignancies between 2010 and 2019. We calculated the Fragility Index (FI) supporting each approval, using methods to account for time-to-event. We compared FI and trial and approval characteristics using Mann-Whitney U and Kruskal-Wallis test. Using logistic regression, we examined study characteristics associated with withdrawal of consent or lost to follow-up (WCLFU) exceeding the calculated FI. Results: The median FI among 125 included studies was 23 (range 1-322). The FI was ≤10 in 35 studies (28%), 11-20 in 21 (17%), and >20 in 69 (55%). The median FI/Nexp was 7.7% (range 0.1-51.7%). The median FI was significantly lower among approvals processed through the accelerated vs regular pathway (5.5 vs 25, p = 0.001), but there was no difference in median FI/Nexp. The WCLFU exceeded FI in 42% of studies. Overall survival endpoints were more likely to have a WCLFU exceeding FI (OR 3.16, p = 0.003). WCLFU exceeding FI was also associated with a lesser magnitude of effect (median HR 0.69 vs 0.55, p FI. Conclusion: The median FI among all trials was 23, and WCLFU exceeded FI in 42%. Comparative trials in solid tumors supporting approval through the accelerated pathway are more fragile compared to trials approved through the regular pathway, an observation likely explained by a lower sample size in the experimental arm