291 research outputs found
Reliability of an âAt-Homeâ Method for Monitoring Resting and Reactive Autonomic Nervous System Activity in Children:A Pilot Study
Background: Heart rate variability (HRV), an index of the functional status of the autonomic nervous system (ANS), provides an opportunity for early detection of ANS dysfunction. Lower resting, vagally related HRV parameters are associated with increased risk of physical and mental illness. External factors influencing the ANS, such as the testing environment, may impact the interpretation of HRV. This studyâs main aim was to determine the reliability of HRV resting and reactivity tests performed at home with children aged 4â9 years. Methods: Fourteen healthy children (female n = 8) aged 6.8 ± 1.5 years participated. Two HRV tests were performed at home via online supervision 7 days apart using a Polar H10 heart rate monitor. The absolute and relative reliability of the pre-exercise resting (5 min) and sub-maximal exercise step test recovery (4 Ă 30 s segments) HRV time and frequency domains were calculated. Results: The Pearson correlation coefficients for day 1 versus day 7 for the vagal activity HRV domains (RMSSD log) at rest and in the first 30 s and 30â60 s of recovery indicated good-to-excellent relative reliability (r > 0.8, p < 0.01). Absolute reliability was moderate for the resting RMSSD log, with a coefficient of variation (CV) of 5.2% (90% CI: 3.9, 7.8%), high for the first 30 s of standing recovery, with a CV of 10.7% (90% CI: 8.2, 15.7%), and moderate for 30â60 s of recovery, with a CV of 8.7% (90% CI: 6.6, 12.9%). Conclusions: The findings of this pilot study indicate that the resting and exercise recovery HRV measures of vagal activity can be measured reliably at home in children. This represents a novel âat-homeâ protocol for monitoring ANS health and development in children.</p
Physical activity and cognitive function in middle-aged adults: a cross-sectional analysis of the PATH through life study
ObjectivesInvestigate the independent associations of objectively measured or self-reported physical activity at different intensities with cognitive performance in middle-aged adults.DesignCross-sectional.Methods156 middle-aged adults (age: 40.6â±â1.5, 58.3% female) participated in the physical activity sub-study of the Personality and Total Health through life (PATH) project. Physical activity was measured objectively with the SenseWearâą armband (SWA), worn for seven consecutive days, and measured via self-report with a Physical Activity Recall survey (PAR). Cognitive performance was assessed with the Symbol Digit Modalities Test, the Digit Span Backwards, and an Immediate and Delayed Recall task. Associations between physical activity intensity and cognitive function were investigated in general linear models, controlling for age, sex, and education.ResultsNeither objectively measured nor self-reported physical activity were associated with cognitive function at light-, moderate-, vigorous-, or combined moderate-to-vigorous intensity in this cohort of well educated, healthy middle-aged adults. Sensitivity analyses with additional moderators (e.g., body mass index, hypertension, alcohol intake) and the use of composite cognitive measures did not alter the results.ConclusionIn this cohort of middle-aged adults, objectively measured and self-reported physical activity do not appear to be associated with cognitive function. Longitudinal follow-ups utilising objective physical activity measures may be important in determining the impact of mid-life behaviours on the trajectory of cognitive changes into older age
A deuterium nuclear magnetic resonance study of chain disorder in lamellar potassium palmitate: The effect of long and short chain guests
The deuterium magnetic resonance spectra of lamellar phases of host perdeuterated potassium palmitate mixed with varying amounts of guest protiated potassium octanoate and behenate and 86.3âmol% D2O are reported. At higher temperatures, the short chain guests give rise to more fluidity and the long chain guests give rise to less fluidity towards the end of the host chain. At low temperatures there are changes in the interaction between the polar head group and the water which depend on sample composition. The transition from the lamellar phase to the low temperature gel phase is investigated and in some cases the gel phase is found to be a complicated many-phase region, at least for the water. The spectral results are presented in detail but compact and empirical methods of analysis are also investigated
A deuterium nuclear magnetic resonance study of chain disorder in lamellar potassium palmitate: The effect of long and short chain guests
The deuterium magnetic resonance spectra of lamellar phases of host perdeuterated potassium palmitate mixed with varying amounts of guest protiated potassium octanoate and behenate and 86.3âmol% D2O are reported. At higher temperatures, the short chain guests give rise to more fluidity and the long chain guests give rise to less fluidity towards the end of the host chain. At low temperatures there are changes in the interaction between the polar head group and the water which depend on sample composition. The transition from the lamellar phase to the low temperature gel phase is investigated and in some cases the gel phase is found to be a complicated many-phase region, at least for the water. The spectral results are presented in detail but compact and empirical methods of analysis are also investigated
Bluecap: A geospatial model to assess regional economic-viability for mineral resource development
© 2020 Frontier mineral exploration is often exclusively focused on assessing geological potential without consideration for the economic viability of resource development. This strategy may overlook potentially prosperous zones for more geologically-favoured but financially-disadvantageous regions, or conversely, may introduce implicit biases against potential developments without due regard to underlying economies of scale or proximity to infrastructure. Accordingly, in this paper, we introduce a numerical model aimed at identifying economic fairways, i.e. areas permissive to mineral development from an economic perspective. The model, Bluecap, combines large-scale infrastructure and geological datasets to conduct geospatial analysis of the economic-viability of mining operations across Australia. We provide a detailed description of the inputs and assumptions that underlie the cost models employed in Bluecap, outlining the methods used to evaluate mining, processing, administrative and infrastructure expenses. We also describe the databases used by the model to evaluate available infrastructure, transportation distances and depth of cover. Finally, we present examples that demonstrate the use of the Bluecap model on regions around Mount Isa and the Murray Basin to verify its ability to evaluate commercially feasible mineral prospects. While the immediate utility of this model stands to benefit mineral explorers, its ability to map mineral economic fairways also provides an objective, evidence base to underpin government decision making with respect to position of new infrastructure and consideration of competing land use claims
âChance allâ â A Simple 3D6 Dice Stopping Game to Explore Probability and Risk vs Reward
âChance allâ is a simple 3D6 dice game that explores a playerâs attitude to risk vs reward. Strategies for playing the game are explored ranging from zero risk to more complex forms of risk, based on an appreciation of the odds; those strategies more likely to win are identified. In addition, the game may be an indirect measure of an individualâs bias towards risk vs reward and how that bias alters through the game as the likelihood of winning and losing changes. It can be used as a simple introductory teaching tool for the Gaussian distribution to examine chance and probability, in evolution and computing science, together with psychological aspects of gameplay
Defining freshwater as a natural resource: a framework linking water use to the area of protection natural resources
© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Purpose: While many examples have shown unsustainable use of freshwater resources, existing LCIA methods for water use do not comprehensively address impacts to natural resources for future generations. This framework aims to (1) define freshwater resource as an item to protect within the Area of Protection (AoP) natural resources, (2) identify relevant impact pathways affecting freshwater resources, and (3) outline methodological choices for impact characterization model development. Methods: Considering the current scope of the AoP natural resources, the complex nature of freshwater resources and its important dimensions to safeguard safe future supply, a definition of freshwater resource is proposed, including water quality aspects. In order to clearly define what is to be protected, the freshwater resource is put in perspective through the lens of the three main safeguard subjects defined by Dewulf et al. (2015). In addition, an extensive literature review identifies a wide range of possible impact pathways to freshwater resources, establishing the link between different inventory elementary flows (water consumption, emissions, and land use) and their potential to cause long-term freshwater depletion or degradation. Results and discussion: Freshwater as a resource has a particular status in LCA resource assessment. First, it exists in the form of three types of resources: flow, fund, or stock. Then, in addition to being a resource for human economic activities (e.g., hydropower), it is above all a non-substitutable support for life that can be affected by both consumption (source function) and pollution (sink function). Therefore, both types of elementary flows (water consumption and emissions) should be linked to a damage indicator for freshwater as a resource. Land use is also identified as a potential stressor to freshwater resources by altering runoff, infiltration, and erosion processes as well as evapotranspiration. It is suggested to use the concept of recovery period to operationalize this framework: when the recovery period lasts longer than a given period of time, impacts are considered to be irreversible and fall into the concern of freshwater resources protection (i.e., affecting future generations), while short-term impacts effect the AoP ecosystem quality and human health directly. It is shown that it is relevant to include this concept in the impact assessment stage in order to discriminate the long-term from the short-term impacts, as some dynamic fate models already do. Conclusions: This framework provides a solid basis for the consistent development of future LCIA methods for freshwater resources, thereby capturing the potential long-term impacts that could warn decision makers about potential safe water supply issues in the future
Ironâcatalyzed borrowing hydrogen CâAlkylation of oxindoles with alcohols
A general and efficient iron-catalyzed C-alkylation of oxindoles has been developed. This borrowing hydrogen approach employs a (cyclopentadienone)iron carbonyl complex (2 mol %) and exhibits a broad reaction scope, allowing benzylic and simple primary and secondary aliphatic alcohols to be employed as alkylating agents. A variety of oxindoles undergo selective monoC(3)-alkylation in good to excellent isolated yields (28 examples, 50- 92% yield, 79% average yield)
The synthesis of the rhamnogalacturonan II component 3-deoxy-D-manno-2-octulosonic acid (Kdo) is required for pollen tube growth and elongation
Despite a very complex structure, the sugar composition of the rhamnogalacturonan II (RG-II) pectic fraction is extremely conserved. Among its constituting monosaccharides is the seldom-observed eight-carbon sugar 3-deoxy-D-manno-octulosonic acid (Kdo), whose phosphorylated precursor is synthesized by Kdo-8-P synthase. As an attempt to alter specifically the RG-II structure in its sugar composition and assess the consequences on the function of RG-II in cell wall and its relationship with growth, Arabidopsis null mutants were sought in the genes encoding Kdo-8-P synthase. Here, the isolation and characterization of one null mutant for the isoform 1 (AtkdsA1-S) and two distinct null mutants for the isoform 2 of Arabidopsis Kdo-8-P synthase (AtkdsA2-V and AtkdsA2-S) are described. Evidence is provided that AtkdsA2 gene expression is preferentially associated with plantlet organs displaying a meristematic activity, and that it accounts for 75% of the mRNAs to be translated into Kdo-8-P synthase. Furthermore, this predominant expression of AtKDSA2 over AtKDSA1 was confirmed by quantification of the cytosolic Kdo content in the mutants, in a variety of ecotypes. The inability to identify a double knockout mutant originated from pollen abortions, due to the inability of haploid pollen of the AtkdsA1- AtkdsA2- genotype to form an elongated pollen tube properly and perform fertilization
Multiple Folding Pathways of the SH3 domain
Experimental observations suggest that proteins follow different pathways
under different environmental conditions. We perform molecular dynamics
simulations of a model of the SH3 domain over a broad range of temperatures,
and identify distinct pathways in the folding transition. We determine the
kinetic partition temperature --the temperature for which the SH3 domain
undergoes a rapid folding transition with minimal kinetic barriers-- and
observe that below this temperature the model protein may undergo a folding
transition via multiple folding pathways. The folding kinetics is characterized
by slow and fast pathways and the presence of only one or two intermediates.
Our findings suggest the hypothesis that the SH3 domain, a protein for which
only two-state folding kinetics was observed in previous experiments, may
exhibit intermediates states under extreme experimental conditions, such as
very low temperatures. A very recent report (Viguera et al., Proc. Natl. Acad.
Sci. USA, 100:5730--5735, 2003) of an intermediate in the folding transition of
the Bergerac mutant of the alpha-spectrin SH3 domain protein supports this
hypothesis.Comment: 16 pages, 4 figures To be published in the "Journal of Molecular
Biology
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