Straight Line Orbits in Hamiltonian Flows

We investigate periodic straight-line orbits (SLO) in Hamiltonian force fields using both direct and inverse methods. A general theorem is proven for natural Hamiltonians quadratic in the momenta in arbitrary dimension and specialized to two and three dimension. Next we specialize to homogeneous potentials and their superpositions, including the familiar H\'enon-Heiles problem. It is shown that SLO's can exist for arbitrary finite superpositions of $N$-forms. The results are applied to a family of generalized H\'enon-Heiles potentials having discrete rotational symmetry. SLO's are also found for superpositions of these potentials.Comment: laTeX with 6 figure

Barriers and facilitators to achieving food security during the COVID-19 pandemic

The COVID-19 pandemic has considerably increased food insecurity. To identify where intervention and policy solutions are most needed, we explored barriers to obtaining food and predictors of experiencing food insecurity due to the COVID-19 pandemic. Between May and July 2020, we conducted cross-sectional online surveys with two convenience samples of U.S. adults (Study 1: n = 2,219, Study 2: n = 810). Roughly one-third of participants reported experiencing food insecurity due to the COVID-19 pandemic (Study 1: 32%, Study 2: 35%). Between one-third and half reported using the charitable food system (Study 1: 36%, Study 2: 46%). The majority of participants experienced barriers to getting food (Study 1: 84%, Study 2: 88%), of which the most commonly reported were not having enough money to buy food (Study 1: 48%; Study 2: 53%) and worrying about getting COVID-19 at the store (Study 1: 50%; Study 2: 43%). Higher education was associated with greater risk of food insecurity in both studies (all p < 0.05). Receipt of aid from SNAP buffered against the association between financial struggles and food insecurity in Study 1 (p = 0.03); there was also some evidence of this effect in Study 2 (p = 0.05). Our findings suggest that food insecurity might be reduced by mitigating financial struggles (e.g., by increasing access to SNAP) and by addressing barriers to obtaining food (e.g., by expanding accessibility of food delivery programs)

A reduction theorem for a conjecture on products of two ¿-decomposable groups

[EN] For a set of primes pi, a group X is said to be pi-decomposable if X = X-pi x X-pi' is the direct product of a pi-subgroup X-pi and a pi'-subgroup X-pi', where pi' is the complementary of pi in the set of all prime numbers. The main result of this paper is a reduction theorem for the following conjecture: "Let pi be a set of odd primes. If the finite group G = AB is a product of two pi-decomposable subgroups A = A(pi) x A(pi') and B = B-pi x B-pi', then A(pi)B(pi) = B(pi)A(pi) and this is a Hall pi-subgroup of G." We establish that a minimal counterexample to this conjecture is an almost simple group. The conjecture is then achieved in a forthcoming paper. (C) 2013 Elsevier Inc. All rights reserved.The second and third author have been supported by Proyecto MTM2010-19938-C03-02, Ministerio de Economia y Competitividad, Spain. The first author would like to thank the Universitat de Valencia and the Universitat Politecnica de Valencia for their warm hospitality during the preparation of this paper. He has been also supported by RFBR project 13-01-00469.Kazarin, LS.; Martínez Pastor, A.; Perez Ramos, MD. (2013). A reduction theorem for a conjecture on products of two ¿-decomposable groups. Journal of Algebra. 379:301-313. https://doi.org/10.1016/j.jalgebra.2013.01.017S30131337

Impact of taxes and warning labels on red meat purchases among US consumers: A randomized controlled trial

Background AU Policies: Pleaseconfirmthatallheadinglevelsarerepresentedcorrectly to reduce red meat intake are important for mitigating : climate change and improving public health. We tested the impact of taxes and warning labels on red meat purchases in the United States. The main study question was, will taxes and warning labels reduce red meat purchases? Methods and findings We recruited 3,518 US adults to participate in a shopping task in a naturalistic online grocery store from October 18, 2021 to October 28, 2021. Participants were randomized to one of 4 conditions: control (no tax or warning labels, n = 887), warning labels (health and environmental warning labels appeared next to products containing red meat, n = 891), tax (products containing red meat were subject to a 30% price increase, n = 874), or combined warning labels + tax (n = 866). We used fractional probit and Poisson regression models to assess the co-primary outcomes, percent, and count of red meat purchases, and linear regression to assess the secondary outcomes of nutrients purchased. Most participants identified as women, consumed red meat 2 or more times per week, and reported doing all of their household's grocery shopping. The warning, tax, and combined conditions led to lower percent of red meat-containing items purchased, with 39% (95% confidence interval (CI) [38%, 40%]) of control participants' purchases containing red meat, compared to 36% (95% CI [35%, 37%], p = 0.001) of warning participants, 34% (95% CI [33%, 35%], p < 0.001) of tax participants, and 31% (95% CI [30%, 32%], p < 0.001) of combined participants. A similar pattern was observed for count of red meat items. Compared to the control, the combined condition reduced calories purchased (−312.0 kcals, 95% CI [−590.3 kcals, −33.6 kcals], p = 0.027), while the tax (−10.4 g, 95% CI [−18.2 g, −2.5 g], p = 0.01) and combined (−12.8 g, 95% CI [−20.7 g, −4.9 g], p = 0.001) conditions reduced saturated fat purchases; no condition affected sodium purchases. Warning labels decreased the perceived healthfulness and environmental sustainability of red meat, while taxes increased perceived cost. The main limitations were that the study differed in sociodemographic characteristics from the US population, and only about 30% to 40% of the US population shops for groceries online. Conclusions Warning labels and taxes reduced red meat purchases in a naturalistic online grocery store. Trial Registration: http://www.clinicaltrials.gov/NCT04716010

The impact of pictorial health warnings on purchases of sugary drinks for children: A randomized controlled trial

Background Pictorial warnings on tobacco products are promising for motivating behavior change, but few studies have examined pictorial warnings for sugary drinks, especially in naturalistic environments. This study aimed to examine the impact of pictorial warnings on parents' purchases of sugary drinks for their children in a naturalistic store laboratory. Methods and findings Parents of children ages 2 to 12 (n = 325, 25% identifying as Black, 20% Hispanic) completed a shopping task in a naturalistic store laboratory in North Carolina. Participants were randomly assigned to a pictorial warnings arm (sugary drinks displayed pictorial health warnings about type 2 diabetes and heart damage) or a control arm (sugary drinks displayed a barcode label). Parents selected 1 beverage and 1 snack for their child, as well as 1 household good; one of these items was selected for them to purchase and take home. The primary outcome was whether parents purchased a sugary drink for their child. Secondary outcomes included reactions to the trial labels, attitudes toward sugary drinks, and intentions to serve their child sugary drinks. Pictorial warnings led to a 17-percentage point reduction in purchases of sugary drinks (95% CI for reduction: 7% to 27%), with 45% of parents in the control arm buying a sugary drink for their child compared to 28% in the pictorial warning arm (p = 0.002). The impact of pictorial warnings on purchases did not differ by any of the 13 participant characteristics examined (e.g., race/ethnicity, income, education, and age of child). Pictorial warnings also led to lower calories (kcal), purchased from sugary drinks (82 kcal in the control arm versus 52 kcal in the pictorial warnings arm, p = 0.003). Moreover, pictorial warnings led to lower intentions to serve sugary drinks to their child, feeling more in control of healthy eating decisions, greater thinking about the harms of sugary drinks, stronger negative emotional reactions, greater anticipated social interactions, lower perceived healthfulness of sugary drinks for their child, and greater injunctive norms to limit sugary drinks for their child (all p 0.05). Conclusions Pictorial warnings reduced parents' purchases of sugary drinks for their children in this naturalistic trial. Warnings on sugary drinks are a promising policy approach to reduce sugary drink purchasing in the US

Great Artesian Basin authigenic carbonates as natural analogues for mineralisation trapping

This project is the first to comprehensively investigate the controls on the formation of authigenic carbonates in low salinity, siliciclastic aquifers of the Great Artesian Basin. These processes are\ua0natural analogues for mineralisation trapping of CO2 during geo-sequestration. Calcite is the main carbonate present. Analyses included elemental composition, C and O stable isotopes, fluid inclusion analyses including\ua0gas isotopes, SEM-EDS and QEMSCAN, and X-ray micro-CT scanning.\ua0The samples reflect\ua0a variety of fluid origins, compositions, and temperatures of precipitation.\ua0Differentiating between carbonate formed via different mechanisms, and determining controls on the extent of authigenic carbonate formation, could lead to options for engineered accelerated mineralisation in reservoirs

Traçando mapas: a teoria histórico-cultural e as contribuições para a pesquisa com crianças e suas espacialidades

Este texto busca fazer uma reflexão sobre as pesquisas sistematizadas no campo da infância, tendo como enfoque principal as estratégias de pesquisas “com crianças”. O recorte ao qual nos dedicamos são as relações que as crianças estabelecem com o meio, tendo como foco principal as suas espacialidades. A partir das contribuições de pesquisas que se aportam em estratégias de natureza qualitativas e fundamentadas nos aportes da teoria históricas cultural, elege-se o conceito de vivência (perejivanie) como mote em torno do qual nossos trabalhos são desenvolvidos. Para isso, traça-se, inicialmente, a origem da pesquisa com base em paradigmas positivistas e evidenciam-se alguns caminhos que buscaram romper com essa perspectiva: os postulados etnográficos de Malinovky e Boas; o Interacionismo simbólico, cujo precursor é George Herbert Mead; a Etnometodologia de Harold Garfinkel; as contribuições de Marx e os princípios estabelecidos por Vigotski e seus colaboradores.</p

Improved tests of extra-dimensional physics and thermal quantum field theory from new Casimir force measurements

We report new constraints on extra-dimensional models and other physics beyond the Standard Model based on measurements of the Casimir force between two dissimilar metals for separations in the range 0.2--1.2 $\mu$m. The Casimir force between an Au-coated sphere and a Cu-coated plate of a microelectromechanical torsional oscillator was measured statically with an absolute error of 0.3 pN. In addition, the Casimir pressure between two parallel plates was determined dynamically with an absolute error of $\approx 0.6$ mPa. Within the limits of experimental and theoretical errors, the results are in agreement with a theory that takes into account the finite conductivity and roughness of the two metals. The level of agreement between experiment and theory was then used to set limits on the predictions of extra-dimensional physics and thermal quantum field theory. It is shown that two theoretical approaches to the thermal Casimir force which predict effects linear in temperture are ruled out by these experiments. Finally, constraints on Yukawa corrections to Newton's law of gravity are strengthened by more than an order of magnitude in the range 56 nm to 330 nm.Comment: Revtex 4, 35 pages, 14 figures in .gif format, accepted for publication in Phys. Rev.

Bats of Bako National Park, Sarawak, Malaysian Borneo

Two separate assessments on bats diversity were conducted in Bako National Park for about 12 trapping-nights. Our first assessment was conducted from 8th to 12th February 2005 followed by the second assessment on the 28th August to 3rd September 2005. A total of 295 individuals from 22 species of bats were captured using mist-nets and harp traps during the survey, which accumulated to 226 trapping-nights. Hipposideros cervinus was recorded as the most abundance species with 30.85% of total captures. Total of eight new geographic records have been added to this park: Emballonura monticola, Rhinolophus luctus, Hipposideros ater, Hipposideros bicolor, Myotis muricola, Myotis ater, Pipistrellus vondermanni and Kerivoula pellucida. With this additional record, now there are at least 34 species of bats known to occur in Bako National Park. A complete and long term study covering other areas not included in this study would definitely increase bat diversity found in these park