Jahn-Teller versus quantum effects in the spin-orbital material LuVO3

We report on combined neutron and resonant x-ray scattering results, identifying the nature of the spin-orbital ground state and magnetic excitations in LuVO3 as driven by the orbital parameter. In particular, we distinguish between models based on orbital Peierls dimerization, taken as a signature of quantum effects in orbitals, and Jahn-Teller distortions, in favor of the latter. In order to solve this long-standing puzzle, polarized neutron beams were employed as a prerequisite in order to solve details of the magnetic structure, which allowed quantitative intensity-analysis of extended magnetic excitation data sets. The results of this detailed study enabled us to draw definite conclusions about classical vs quantum behavior of orbitals in this system and to discard the previous claims about quantum effects dominating the orbital physics of LuVO3 and similar systems.Comment: Phys. Rev. B 91, 161104(R) (2015

Towards understanding the magnetic properties of the breathing pyrochlore compound Ba3Yb2Zn5O11: A single crystal study

Ba3Yb2Zn5O11 is unique among breathing pyrochlore compounds for being in the nearly decoupled limit where inter-tetrahedron interactions are weak, hosting isolated clusters or "molecular magnet" like tetrahedra of magnetic ytterbium (Yb3+) ions. In this work, we present the first study carried out on single-crystal samples of the breathing pyrochlore Ba3Yb2Zn5O11, using a variety of magnetometry and neutron scattering techniques along with theoretical modeling. We employ inelastic neutron scattering to investigate the magnetic dynamics as a function of applied field (with respect to both magnitude and direction) down to a temperature of 70 mK, where inelastic scattering reveals dispersionless bands of excitations as found in earlier powder sample studies, in good agreement with a single-tetrahedron model. However, diffuse neutron scattering at zero field and dc-susceptibility at finite field exhibit features suggesting the presence of excitations at low-energy that are not captured by the single tetrahedron model. Analysis of the local structure down to 2 K via pair distribution function analysis finds no evidence of structural disorder. We conclude that effects beyond the single tetrahedron model are important in describing the low-energy, low temperature physics of Ba3Yb2Zn5O11, but their nature remains undetermined

Reply to "Comment on: 'Case for a U(1)π_\pi Quantum Spin Liquid Ground State in the Dipole-Octupole Pyrochlore Ce2Zr2O7\mathrm{Ce}_2\mathrm{Zr}_2\mathrm{O}_7' "

In his comment [arXiv:2209.03235], S. W. Lovesey argues that our analysis of neutron scattering experiments performed on Ce$_2$Zr$_2$O$_7$ is invalid. Lovesey argues that we have not properly accounted for the higher-order multipolar contributions to the magnetic scattering and that our use of pseudospin-$1/2$ operators to describe the scattering is inappropriate. In this reply, we show that the multipolar corrections discussed by Lovesey only become significant at scattering wavevectors exceeding those accessed in our experiments. This in no way contradicts or undermines our work, which never claimed a direct observation of scattering from higher-order multipoles. We further show that Lovesey's objections to our use of pseudospins are unfounded, and that the pseudospin operators are able to describe all magnetic scattering processes at the energy scale of our experiments, far below the crystal field gap. Finally, we comment on certain assumptions in Lovesey's calculations of the scattering amplitude which are inconsistent with experiment.Comment: 6 pages, 1 figur

Children's very low food security is associated with increased dietary intakes in energy, fat, and added sugar among Mexican-origin children (6-11 y) in Texas border Colonias

<p>Abstract</p> <p>Background</p> <p>Food insecurity among Mexican-origin and Hispanic households is a critical nutritional health issue of national importance. At the same time, nutrition-related health conditions, such as obesity and type 2 diabetes, are increasing in Mexican-origin youth. Risk factors for obesity and type 2 diabetes are more common in Mexican-origin children and include increased intakes of energy-dense and nutrient-poor foods. This study assessed the relationship between children's experience of food insecurity and nutrient intake from food and beverages among Mexican-origin children (age 6-11 y) who resided in Texas border <it>colonias</it>.</p> <p>Methods</p> <p>Baseline data from 50 Mexican-origin children were collected in the home by trained <it>promotora</it>-researchers. All survey (demographics and nine-item child food security measure) and 24-hour dietary recall data were collected in Spanish. Dietary data were collected in person on three occasions using a multiple-pass approach; nutrient intakes were calculated with NDS-R software. Separate multiple regression models were individually fitted for total energy, protein, dietary fiber, calcium, vitamin D, potassium, sodium, Vitamin C, and percentage of calories from fat and added sugars.</p> <p>Results</p> <p>Thirty-two children (64%) reported low or very low food security. Few children met the recommendations for calcium, dietary fiber, and sodium; and none for potassium or vitamin D. Weekend intake was lower than weekday for calcium, vitamin D, potassium, and vitamin C; and higher for percent of calories from fat. Three-day average dietary intakes of total calories, protein, and percent of calories from added sugars increased with declining food security status. Very low food security was associated with greater intakes of total energy, calcium, and percentage of calories from fat and added sugar.</p> <p>Conclusions</p> <p>This paper not only emphasizes the alarming rates of food insecurity for this Hispanic subgroup, but describes the associations for food insecurity and diet among this sample of Mexican-origin children. Child-reported food insecurity situations could serve as a screen for nutrition problems in children. Further, the National School Lunch and School Breakfast Programs, which play a major beneficial role in children's weekday intakes, may not be enough to keep pace with the nutritional needs of low and very low food secure Mexican-origin children.</p

Global Use of Traditional and Complementary Medicine in Childhood Cancer: A Systematic Review

Purpose: Traditional and complementary medicine (T&CM) strategies are commonly used in pediatric oncology. Patterns may vary based on country income. We systematically reviewed published studies describing T&CM use among pediatric oncology patients in low-income countries (LIC/LMIC), middle-income countries (UMIC), and high-income countries (HIC). Objectives included describing estimated prevalence of use, reasons for use, perceived effectiveness, modalities used, rates of disclosure, and reporting of delayed or abandoned treatment. Methods: MEDLINE, EMBASE, Global Health, CINAHL, PsycINFO, Allied and Complementary Medicine Database, Cochrane Database of Systematic Reviews, and ProceedingsFirst were searched. Inclusion criteria were primary studies involving children younger than the age of 18 years, undergoing active treatment of cancer, and any T&CM use. Exclusion criteria included no pediatric oncology–specific outcomes and studies involving only children off active treatment. Data were extracted by two reviewers using a systematic data extraction form determined a priori. Results: Sixty-five studies published between 1977 and 2015 were included, representing 61 unique data sets and 7,219 children from 34 countries. The prevalence of T&CM use ranged from 6% to 100%. Median rates of use were significantly different in LIC/LMIC (66.7% ± 19%), UMIC (60% ± 26%), and HIC (47.2% ± 20%; P = .02). Rates of disclosure differed significantly by country income, with higher median rates in HIC. Seven studies reported on treatment abandonment or delays. Conclusion: The use of T&CM in pediatric oncology is common worldwide, with higher median prevalence of use reported in LIC/LMIC. Further research is warranted to examine the impact on treatment abandonment and delay