Evaluation of Fat-free Mass Characteristics at Different Adiposity Levels: Impact of Weight Status Stratification Method

The method used to stratify weight status when evaluating fat-free mass (FFM) characteristics has primarily been based upon body mass index (BMI) and not body fat percent (BF%). As a result, it is unknown whether deviations in FFM characteristics are similar when stratifying weight status based upon BMI or BF%. Purpose: The purpose of this study was to evaluate FFM characteristics at different adiposity levels when stratifying weight status via BMI and BF%. Methods: 150 adults (50% males) participated in this study. 3-compartment (3C) model body composition was based upon body density (Db) via air displacement plethysmography (ADP) and total body water via bioimpedance analysis. FFM density (DFFM), residual (RFFM), and hydration (HFFM)were evaluated in all subjects. The Db obtained from a stand-alone assessment of ADP (2C-Db) and 3C model (3C-Db)were also compared between groups. Subjects were stratified based upon weight status (BMI and BF%). First, subjects were divided into a normal weight (NW-BMI), overweight (OW-BMI) or obese (OB-BMI) group, which were based upon BMI values of 18.5-24.99 kg/m2 (n=50), 25.0-29.99 kg/m2 (n=50), and ³ 30.0 kg/m2 (n=50), respectively. Next, subjects were divided into groups based upon BF% where normal weight BF% values (NW-BF%) for males and females were \u3c 25 and 35% (n=81), respectively, and obese BF% values (OB-BF%) were ³25 and 35% (n=69), respectively. Results: The DFFM ranged from 1.096 – 1.097 g/cm3 for all groups in both weight status stratification methods (all p \u3e 0.05). HFFM and RFFM were similar for all comparisons and ranged from 73.99 – 74.33% and 25.67 – 26.01%, respectively, for BMI groups and 74.02 – 74.26% and 25.74 – 25.98%, respectively, for BF% groups (all p \u3e 0.05). In contrast, the 3C-Db (1.050, 1.036, and 1.013 g/cm3) and 2C-Db (1.051, 1.036, and 1.014 g/cm3) were statistically significant for all comparisons between NW-BMI, OW-BMI, and OB-BMI respectively (all p \u3c 0.05). Furthermore, 3C-Db (1.051 and 1.011 g/cm3) and 2C-Db (1.052 and 1.012 g/cm3) were significantly different when comparing NW-BF% and OB-BF% (both p \u3c 0.05). CONCLUSIONS: Previous research has reported the FFM characteristics when stratifying weight status via BMI classification. As a result, it was unknown whether deviations in FFM characteristics existed when stratifying by BF%. Uniquely, the current study findings revealed that FFM characteristics are similar between groups regardless of the weight status stratification method (BMI or BF%)

Unlocking the potential of polymeric desalination membranes by understanding molecular-level interactions and transport mechanisms

Polyamide reverse osmosis (PA-RO) membranes achieve remarkably high water permeability and salt rejection, making them a key technology for addressing water shortages through processes including seawater desalination and wastewater reuse. However, current state-of-the-art membranes suffer from challenges related to inadequate selectivity, fouling, and a poor ability of existing models to predict performance. In this Perspective, we assert that a molecular understanding of the mechanisms that govern selectivity and transport of PA-RO and other polymer membranes is crucial to both guide future membrane development efforts and improve the predictive capability of transport models. We summarize the current understanding of ion, water, and polymer interactions in PA-RO membranes, drawing insights from nanofiltration and ion exchange membranes. Building on this knowledge, we explore how these interactions impact the transport properties of membranes, highlighting assumptions of transport models that warrant further investigation to improve predictive capabilities and elucidate underlying transport mechanisms. We then underscore recent advances in in situ characterization techniques that allow for direct measurements of previously difficult-to-obtain information on hydrated polymer membrane properties, hydrated ion properties, and ion&ndash;water&ndash;membrane interactions as well as powerful computational and electrochemical methods that facilitate systematic studies of transport phenomena. &nbsp;</p

Oxidative Alteration of Ferrous Smectites: A Formation Pathway for Martian Nontronite?

Ferric (Fe3+-bearing) smectites, including nontronite, constitute the majority of hydrous mineral exposures observed on Mars. These smectite exposures are commonly interpreted as weathering products of Martian basaltic crust. However, ferrous (Fe2+-dominated) smectites, not ferric, are the thermo-dynamically predicted products of weathering in anoxic conditions, as predicted for early Mars. Earth was anoxic until the Proterozoic Great Oxidation Event; Mars likely experienced an analogous oxidative evolution to its present oxidized state, but the timing of this evolution is unresolved. We hypothesize that Fe3+-smectites observed by orbital spectroscopy are not the initial products of Noachian-era chemical weathering, but are instead the oxidative products of primary Fe2+-smectites. To test this hypothesis experimentally, we synthesized ferrous smectites and exposed them to Mars-relevant oxidants

Effects of Heat Exposure on Body Water Assessed using Single-Frequency Bioelectrical Impedance Analysis and Bioimpedance Spectroscopy

International Journal of Exercise Science 10(7): 1085-1093, 2017. The purpose of this study was to determine if heat exposure alters the measures of total body water (TBW), extracellular water (ECW), and intracellular water (ICW) in both single-frequency bioelectrical impedance analysis (BIA) and bioimpedance spectroscopy (BIS). Additionally, we sought to determine if any differences exist between the BIA and BIS techniques before and after brief exposure to heat. Body water was evaluated for twenty men (age=24±4 years) in a thermoneutral environment (22°C) before (PRE) and immediately after (POST) 15 min of passive heating (35°C) in an environmental chamber. The mean difference and 95% limits of agreement at PRE demonstrated that BIS yielded significantly higher body water values than BIA (all p0.05; 0.2±1.5kg). Additionally, the ES of the mean differences at POST were trivial to small and the r-values were high (r≥0.96). When analyzing the changes in body water before and after heat exposure, POST values for BIS were significantly higher than PRE (all

A dual process account of creative thinking

This article explicates the potential role played by type 1 thinking (automatic, fast) and type 2 thinking (effortful, logical) in creative thinking. The relevance of Evans's (2007) models of conflict of dual processes in thinking is discussed with regards to creative thinking. The role played by type 1 thinking and type 2 thinking during the different stages of creativity (problem finding and conceptualization, incubation, illumination, verification and dissemination) is discussed. It is proposed that although both types of thinking are active in creativity, the extent to which they are active and the nature of their contribution to creativity will vary between stages of the creative process. Directions for future research to test this proposal are outlined; differing methodologies and the investigation of different stages of creative thinking are discussed. © Taylor & Francis Group, LLC

Churn, Baby, Churn: Strategic Dynamics Among Dominant and Fringe Firms in a Segmented Industry

This paper integrates and extends the literatures on industry evolution and dominant firms to develop a dynamic theory of dominant and fringe competitive interaction in a segmented industry. It argues that a dominant firm, seeing contraction of growth in its current segment(s), enters new segments in which it can exploit its technological strengths, but that are sufficiently distant to avoid cannibalization. The dominant firm acts as a low-cost Stackelberg leader, driving down prices and triggering a sales takeoff in the new segment. We identify a “churn” effect associated with dominant firm entry: fringe firms that precede the dominant firm into the segment tend to exit the segment, while new fringe firms enter, causing a net increase in the number of firms in the segment. As the segment matures and sales decline in the segment, the process repeats itself. We examine the predictions of the theory with a study of price, quantity, entry, and exit across 24 product classes in the desktop laser printer industry from 1984 to 1996. Using descriptive statistics, hazard rate models, and panel data methods, we find empirical support for the theoretical predictions

Algorithmic Complexity for Short Binary Strings Applied to Psychology: A Primer

Since human randomness production has been studied and widely used to assess executive functions (especially inhibition), many measures have been suggested to assess the degree to which a sequence is random-like. However, each of them focuses on one feature of randomness, leading authors to have to use multiple measures. Here we describe and advocate for the use of the accepted universal measure for randomness based on algorithmic complexity, by means of a novel previously presented technique using the the definition of algorithmic probability. A re-analysis of the classical Radio Zenith data in the light of the proposed measure and methodology is provided as a study case of an application.Comment: To appear in Behavior Research Method