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1. Synthesis and characterization of modular polyphosphonate homopolymers and copolymers

   https://doi.org/10.1002/pol.20200066  

   Totsch, Timothy R.; Stanford, Victoria L.; Klep, Oleksander; Burdette, Mary K.; Grant, Benjamin; Foulger, Stephen H.; Gray, Gary M. (June 2020, Journal of Polymer Science)

   Abstract Linear polyphosphonates with the generic formula –[P(Ph)(X)OR′O]_n– (X = S or Se) have been synthesized by polycondensations of P(Ph)(NEt₂)₂and a diol (HOR′OH = 1,4‐cyclohexanedimethanol, 1,4‐benzenedimethanol, tetraethylene glycol, or 1,12‐dodecanediol) followed by reaction with a chalcogen. Random copolymers have been synthesized by polycondensations of P(Ph)(NEt₂)₂and mixture of two of the diols in a 2:1:1 mol ratio followed by reaction with a chalcogen. Block copolymers with the generic formula –[P(Ph)(X)OR′O]_(x + 2)–[P(Ph)(X)OR′O]_(x + 3)– (X = S or Se) have been synthesized by the polycondensations of Et₂N[P(Ph)(X)OR′O]_(x + 2)P(Ph)NEt₂oligomers with HOR′O[P(Ph)(X)OR′O]_(x + 3)H oligomers followed by reaction with a chalcogen. The Et₂N[P(Ph)(X)OR′O]_(x + 2)P(Ph)NEt₂oligomers are prepared by the reaction of an excess of P(Ph)(NEt₂)₂with a diol while the HOR′O[P(Ph)(X)OR′O]_(x + 3)H oligomers are prepared by the reaction of P(Ph)(NEt₂)₂with an excess of the diol. In each case the excess, x is the same and determines the average block sizes. All of the polymers were characterized using¹H,¹³C{¹H}, and³¹P{¹H} NMR spectroscopy, TGA, DSC, and SEC.³¹P{¹H} NMR spectroscopy demonstrates that the random and block copolymers have the expected arrangements of monomers and, in the case of block copolymers, verifies the block sizes. All polymers are thermally stable up to ~300°C, and the arrangements of monomers in the copolymers (block vs. random) affect their degradation temperatures andT_gprofiles. The polymers have weight average MWs of up to 3.8 × 10⁴ Da. 

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2. Intraspecific correlations between growth and defence vary with resource availability and differ within and among populations

   https://doi.org/10.1111/1365-2435.13878  

   Hahn, Philip G.; Keefover‐Ring, Ken; Nguyen, Linh M. N.; Maron, John L. (July 2021, Functional Ecology)

   Abstract A paradigm in the plant defence literature is that defending against herbivores comes at a cost to growth, resulting in a growth–defence trade‐off. However, while there is strong evidence for growth–defence trade‐offs across species, evidence is mixed within species.Several mechanisms can account for this equivocal support within species, but teasing them apart requires examining growth–defence relationships both within and among populations, an approach seldom employed.We examined correlations between plant biomass (growth) and terpene production (defence) within and among populations ofMonarda fistulosa, a perennial herb. We sampled populations from Montana and Wisconsin, regions that differ in resource availability characterized by different summer precipitation and associated abiotic conditions that influence plant productivity.We found negative, neutral and positive growth–defence correlations, depending on the scale examined. Negative correlations occurred across populations originating from divergent regions, positive correlations occurred across populations originating from within the high‐resource region and neutral correlations were found within single populations.Collectively, these results challenge the general expectation of ubiquitous trade‐offs and support emerging views that resource availability (as it affects productivity) shapes the evolution of defence at different scales. A freePlain Language Summarycan be found within the Supporting Information of this article. 

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3. Global spectra of plant litter carbon, nitrogen and phosphorus concentrations and returning amounts

   https://doi.org/10.1111/1365-2745.14250  

   Yuan, Ji; Wu, Fuzhong; Peng, Changhui; Peñuelas, Josep; Vallicrosa, Helena; Sardans, Jordi; Peng, Yan; Wu, Qiqian; Li, Zimin; Heděnec, Petr; et al (April 2024, Journal of Ecology)

   Abstract Litter decomposition is a key ecological process that determines carbon (C) and nutrient cycling in terrestrial ecosystems. The initial concentrations of C and nutrients in litter play a critical role in this process, yet the global patterns of litter initial concentrations of C, nitrogen (N) and phosphorus (P) are poorly understood.We employed machine learning with a global database to quantitatively assess the global patterns and drivers of leaf litter initial C, N and P concentrations, as well as their returning amounts (i.e. amounts returned to soils).The medians of litter C, N and P concentrations were 46.7, 1.1, and 0.1%, respectively, and the medians of litter C, N and P returning amounts were 1.436, 0.038 and 0.004 Mg ha⁻¹ year⁻¹, respectively. Soil and climate emerged as the key predictors of leaf litter C, N and P concentrations. Predicted global maps showed that leaf litter N and P concentrations decreased with latitude, while C concentration exhibited an opposite pattern. Additionally, the returning amounts of leaf litter C, N and P all declined from the equator to the poles in both hemispheres.Synthesis: Our results provide a quantitative assessment of the global concentrations and returning amounts of leaf litter C, N and P, which showed new light on the role of leaf litter in global C and nutrients cycling. 

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4. Fruit and Vegetable Consumption, Food Acquisition Behavior, and Food Insecurity Before and After the COVID-19 Vaccine Rollout

   https://doi.org/10.1097/PHH.0000000000001946  

   Hosler, Akiko S; Chen, Jiacheng; Arroyo, Mariana Torres; Neff, Roni A; Bozlak, Christine T; Romeiko, Xiaobo X; Feingold, Beth J (January 2024, Journal of Public Health Management & Practice)

   Objectives:To assess changes in food acquisition behavior, food insecurity, and dietary behavior and identify factors associated with fruit and vegetable (FV) consumption during the transitional period (before and after the initial vaccine rollout for all adults) of the COVID-19 pandemic. Design:Successive independent samples design. Online surveys were conducted from October 2020 to February 2021 (time 1, before the vaccine rollout) and from October 2021 to December 2021 (time 2, after the vaccine rollout). Descriptive analysis examined changes in food sources, food security, and daily FV consumption in cup equivalents (CEs) from time 1 to time 2. A multivariable logistic regression analysis examined factors associated with FV consumption. Setting:The Capital Region of New York State. Participants:1553 adults 18 years of age and older. Main Outcome Measure:Meeting the 2020-2025 MyPlate daily FV consumption recommendations. Results:There were statistically significant (P< .05) increases in the use of supermarkets, eat-in restaurants, farmers’ markets, and convenience stores from time 1 to time 2. Food insecurity (40.1% vs 39.4%) and FV consumption (2.6 CE vs 2.4 CE) slightly declined but not significantly. Home food procurement such as gardening and foraging (OR, 1.61; 95% CI, 1.08-2.37) and shopping at food co-op/health food stores (OR, 1.64; 95% CI, 1.07-2.49) were significantly associated with the FV outcome, and these relationships were not modified by food security status. Conclusions:The present study highlights the importance of food sources in understanding adult dietary behavior during the transitional period of the pandemic. Continuing efforts to monitor access to food sources, food insecurity, and dietary behavior are warranted as various COVID-related emergency food assistance measures have expired. 

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5. Assessing Postural Instability and Cybersickness Through Linear and Angular Displacement

   https://doi.org/10.1177/0018720819881254  

   Widdowson, Christopher; Becerra, Israel; Merrill, Cameron; Wang, Ranxiao_Frances; LaValle, Steven (October 2019, Human Factors: The Journal of the Human Factors and Ergonomics Society)

   ObjectiveTo examine the hypothesis that constant speed is more comfortable than variable speed profiles and may minimize cybersickness. BackgroundCurrent best practices for virtual reality (VR) content creation suggest keeping any form of acceleration as short and infrequent as possible to mitigate cybersickness. MethodsIn Experiment 1, participants experienced repetitions of simulated linear motion, and in Experiment 2, they experienced repetitions of a circular motion. Three speed profiles were tested in each experiment. Each trial lasted 2 min while standing. Cybersickness was measured using the Simulator Sickness Questionnaire (SSQ) and operationally defined in terms of total severity scores. Postural stability was measured using a Wii Balance Board and operationally defined in terms of center of pressure (COP) path length. Postural measures were decomposed into anterior-posterior and medial-lateral axes and subjected to detrended fluctuation analysis. ResultsFor both experiments, no significant differences were observed between the three speed profiles in terms of cybersickness or postural stability, and none of the baseline postural measures could predict SSQ scores for the speed profile conditions. An axis effect was observed in both experiments such that normalized COP movement was significantly greater along the anterior-posterior axis than the medial-lateral axis. ConclusionResults showed no convincing evidence to support the common belief that constant speed is more comfortable than variable speed profiles for scenarios typical of VR applications. ApplicationThe present findings offer guidelines for the design of locomotion techniques involving traversal in VR environments. 

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