Phenol-crotonaldehyde resins. II. Effect of crotonaldehyde purity on resin properties

Acid-catalyzed polycondensation of phenol and crotonaldehyde results in soluble thermoplastic resins over a broad range of compositions. The thermal and curing behavior of the resins are found to vary markedly with the phenol to crotonaldehyde mole ratio and the purity of crotonaldehyde. Infrared analysis of the resins and their fractions separated by column chromatography indicates that all the resins are structurally similar. The number-average molecular weights of the resins fall in the range of 400 to 600. The resins from distilled crotonaldehyde exhibit higher molecular weights than those from crude crotonaldehyde. The thermal properties of the resins are comparable to the Novolak-type phenol-formaldehyde resins. The thermoplastic nature is retained even at higher fraction of crotonaldehyde, unlike for the conventional Novolak resins

Phenol-crotonaldehyde resins. III. Curing behavior with hexamethylenetetramine

Solid thermoplastic resins were prepared by acid-catalyzed condensation of phenol and crotonaldehyde (both crude and distilled). The thermal and curing properties were compared with the conventional phenol-formaldehyde (PF) novolak resins. Phenol-crotonaldehyde (PC) resins were found to be thermoplastic even after curing with the crosslinking agent hexamethylenetetramine up to 160°C. This curing behavior was observed irrespective of the purity of the crotonaldehyde or the phenol-to-crotonaldehyde mole ratio in the resin. Postcuring of these resins at elevated temperatures yielded insoluble and infusible thermoset products. This unique thermal characteristic could lead to interesting processing possibilities for the resins. The technical feasibility of thermoplastic processing of the PC resins followed by postcure heat treatment for transforming the molded part into a thermoset has been demonstrated

Asymptotic Behavior of the Correlator for Polyakov Loops

The asymptotic behavior of the correlator for Polyakov loop operators separated by a large distance $R$ is determined for high temperature QCD. It is dominated by nonperturbative effects related to the exchange of magnetostatic gluons. To analyze the asymptotic behavior, the problem is formulated in terms of the effective field theory of QCD in 3 space dimensions. The Polyakov loop operator is expanded in terms of local gauge-invariant operators constructed out of the magnetostatic gauge field, with coefficients that can be calculated using resummed perturbation theory. The asymptotic behavior of the correlator is $\exp(-MR)/R$, where $M$ is the mass of the lowest-lying glueball in $(2+1)$-dimensional QCD. This result implies that existing lattice calculations of the Polyakov loop correlator at the highest temperatures available do not probe the true asymptotic region in $R$.Comment: 10 pages, NUHEP-TH-94-2

S^1 \times S^2 as a bag membrane and its Einstein-Weyl geometry

In the hybrid skyrmion in which an Anti-de Sitter bag is imbedded into the skyrmion configuration a S^{1}\times S^{2} membrane is lying on the compactified spatial infinity of the bag [H. Rosu, Nuovo Cimento B 108, 313 (1993)]. The connection between the quark degrees of freedom and the mesonic ones is made through the membrane, in a way that should still be clarified from the standpoint of general relativity and topology. The S^1 \times S^2 membrane as a 3-dimensional manifold is at the same time a Weyl-Einstein space. We make here an excursion through the mathematical body of knowledge in the differential geometry and topology of these spaces which is expected to be useful for hadronic membranesComment: 9pp in latex, minor correction

Covariant derivative expansion of Yang-Mills effective action at high temperatures

Integrating out fast varying quantum fluctuations about Yang--Mills fields A_i and A_4, we arrive at the effective action for those fields at high temperatures. Assuming that the fields A_i and A_4 are slowly varying but that the amplitude of A_4 is arbitrary, we find a non-trivial effective gauge invariant action both in the electric and magnetic sectors. Our results can be used for studying correlation functions at high temperatures beyond the dimensional reduction approximation, as well as for estimating quantum weights of classical static configurations such as dyons.Comment: Minor changes. References added. Paper accepted for publication in Phys.Rev.

The methods and outcomes of cultural adaptations of psychological treatments for depressive disorders: a systematic review.

BACKGROUND: Cultural adaptations of evidence-based psychological treatments (PTs) are important to enhance their universal applicability. The aim of this study was to review systematically the literature on adaptations of PTs for depressive disorders for ethnic minorities in Western countries and for any population in non-Western countries to describe the process, extent and nature of the adaptations and the effectiveness of the adapted treatments. METHOD: Controlled trials were identified using database searches, key informants, previous reviews and reference lists. Data on the process and details of the adaptations were analyzed using qualitative methods and meta-analysis was used to assess treatment effectiveness. RESULTS: Twenty studies were included in this review, of which 16 were included in the meta-analysis. The process of adaptation was reported in two-thirds of the studies. Most adaptations were found in the dimensions of language, context and therapist delivering the treatment. The meta-analysis revealed a statistically significant benefit in favor of the adapted treatment [standardized mean difference (SMD) -0.72, 95% confidence interval (CI) -0.94 to -0.49]. CONCLUSIONS: Cultural adaptations of PTs follow a systematic procedure and lead primarily to adaptations in the implementation of the treatments rather than their content. Such PTs are effective in the treatment of depressive disorders in populations other than those for whom they were originally developed

A simple method of estimating folic acid absorption (a modified faecal excretion method)

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Non-perturbative Debye mass in finite T QCD

Employing a non-perturbative gauge invariant definition of the Debye screening mass m_D in the effective field theory approach to finite T QCD, we use 3d lattice simulations to determine the leading O(g^2) and to estimate the next-to-leading O(g^3) corrections to m_D in the high temperature region. The O(g^2) correction is large and modifies qualitatively the standard power-counting hierarchy picture of correlation lengths in high temperature QCD.Comment: 4 pages, Late

The Finite Temperature SU(2) Savvidy Model with a Non-trivial Polyakov Loop

We calculate the complete one-loop effective potential for SU(2) gauge bosons at temperature T as a function of two variables: phi, the angle associated with a non-trivial Polyakov loop, and H, a constant background chromomagnetic field. Using techniques broadly applicable to finite temperature field theories, we develop both low and high temperature expansions. At low temperatures, the real part of the effective potential V_R indicates a rich phase structure, with a discontinuous alternation between confined (phi=pi) and deconfined phases (phi=0). The background field H moves slowly upward from its zero-temperature value as T increases, in such a way that sqrt(gH)/(pi T) is approximately an integer. Beyond a certain temperature on the order of sqrt(gH), the deconfined phase is always preferred. At high temperatures, where asymptotic freedom applies, the deconfined phase phi=0 is always preferred, and sqrt(gH) is of order g^2(T)T. The imaginary part of the effective potential is non-zero at the global minimum of V_R for all temperatures. A non-perturbative magnetic screening mass of the form M_m = cg^2(T)T with a sufficiently large coefficient c removes this instability at high temperature, leading to a stable high-temperature phase with phi=0 and H=0, characteristic of a weakly-interacting gas of gauge particles. The value of M_m obtained is comparable with lattice estimates.Comment: 28 pages, 5 eps figures; RevTeX 3 with graphic

Long-Term Neurobehavioral and Quality of Life Outcomes of Critically Ill Children after Glycemic Control

© 2019 Elsevier Inc. Objectives: To investigate adaptive skills, behavior, and quality health-related quality of life in children from 32 centers enrolling in the Heart And Lung Failure-Pediatric INsulin Titration randomized controlled trial. Study design: This prospective longitudinal cohort study compared the effect of 2 tight glycemic control ranges (lower target, 80-100 mg/dL vs higher target, 150-180 mg/dL) 1-year neurobehavioral and health-related quality of life outcomes. Subjects had confirmed hyperglycemia and cardiac and/or respiratory failure. Patients aged 2-16 years old enrolled between April 2012 and September 2016 were studied at 1 year after intensive care discharge. The primary outcome, adaptive skills, was assessed using the Vineland Adaptive Behavior Scale. Behavior and health-related quality of life outcomes were assessed as secondary outcomes using the Pediatric Quality of Life and Child Behavior Checklist at baseline and 1-year follow-up. Group differences were evaluated using regression models adjusting for age category, baseline overall performance, and risk of mortality. Results: Of 369 eligible children, 358 survived after hospital discharge and 214 (60%) completed follow-up. One-year Vineland Adaptive Behavior Scale-II composite scores were not different (mean ± SD, 79.9 ± 25.5 vs 79.4 ± 26.9, lower vs higher target; P =.20). Improvement in Pediatric Quality of Life total health from baseline was greater in the higher target group (adjusted mean difference, 8.2; 95% CI, 1.1-15.3; P =.02). Conclusions: One-year adaptive behavior in critically ill children with lower vs higher target glycemic control did not differ. The higher target group demonstrated improvement from baseline in overall health. This study affirms the lack of benefit of lower glucose targeting. Trial registration: ClinicalTrials.gov: NCT01565941