Density‐dependent and density‐independent growth in a population of juvenile sea‐trout,Salmo trutta,assessed using long‐term data from a small stream in Northwest England

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Cholesteryl ester transfer protein in metabolic syndrome

Objective: Low high‐density lipoprotein cholesterol (HDL‐C), hypertriglyceridemia, and small dense‐low density lipoprotein (LDL) are key components of metabolic syndrome (MS). Cholesteryl ester transfer protein (CETP) mediates the transfer of triglycerides (TGs) from TG‐rich lipoproteins to HDL and LDL particles in exchange for cholesteryl esters, leading to low HDL‐C and small dense‐LDL. The aim of this study was to investigate the role of CETP in subjects with MS. Research Methods and Procedures: In a cross‐sectional cohort of 234 middle‐aged men and 252 women randomly selected from the Salzburg Atherosclerosis Prevention Program in Subjects at High Individual Risk (SAPHIR) study, MS was diagnosed according to the National Cholesterol Education Program guidelines. CETP mass was determined by enzyme‐linked immunosorbent assay and LDL size‐by‐gradient polyacrylamide gel electrophoresis. Results: Men and women with MS had lower HDL‐C (45 ± 7 vs. 58 ± 13 and 48 ± 10 vs. 71 ± 14 mg/dL for men and women, respectively; p < 0.001 for all) and higher TG levels (222 ± 71 vs. 98 ± 54 and 167 ± 67 vs. 90 ± 35 mg/dL for men and women, respectively; p < 0.001 for all) than healthy subjects. LDL size was lower in subjects with MS (256 ± 11 Å vs. 267 ± 11 Å and 262 ± 10 Å vs. 273 ± 8 Å for men and women, respectively; p < 0.001 for all). CETP mass was higher in men with MS (1.87 ± 0.78 vs. 1.40 ± 0.65 μg/mL; p < 0.001) but not in women (1.74 ± 0.79 vs. 1.62 ± 0.62 μg/mL). CETP mass correlated inversely with LDL size in both men and women (r = ?0.19, p < 0.01 and r = ?0.13, p < 0.05 in men and women, respectively). Discussion: MS is associated with increased CETP mass in men. Increased CETP mass may be responsible for reduced HDL‐C and reduced LDL particle diameter in MS.     

Obesity in Spanish Schoolchildren: Relationship with Lipid Profile and Insulin Resistance

This article reports cross‐sectional data from a total of 1048 children, 6 to 8 years of age, categorized by presence or absence of obesity, who participated in a voluntary survey of cardiovascular risk factors in Spain over the period of 1998 to 2000, to establish the relationship between obesity and its metabolic consequences at this age. The prevalence of obesity and overweight were 9.4% and 15.7%, respectively, in boys and 10.5% and 18.0%, respectively, in girls. We observed that, in both sexes, obese children had higher triglycerides and lower high‐density lipoprotein‐cholesterol levels than non‐obese children. No differences were found in plasma glucose or low‐density lipoprotein‐cholesterol levels between normal and obese children. However, we observed that insulin levels and the homeostasis model assessment for insulin resistance were significantly (p < 0.001) higher in obese children of both sexes but that free fatty acid levels were lower in obese children than in nonobese children, with a statistical significance in girls (0.72 ± 0.30 vs. 0.61 ± 0.16 mEq/liter). In summary, our survey found some metabolic consequences of obesity similar to those found in adults (elevated triglycerides, insulin, and the homeostasis model assessment for insulin resistance, and lower high‐density lipoprotein‐cholesterol). However, other features (glucose, total cholesterol, low‐density lipoprotein‐cholesterol, and free fatty acid levels) were found to behave differently, indicating that the association of obesity with risk factors seems to change as the children age and may depend on the chronology of sexual maturation.     

Declines in breeding site fidelity in an increasing population of White Storks Ciconia ciconia

Following a steep decline, White Stork Ciconia ciconia populations in Germany are currently increasing, allowing us to examine potential density‐dependent effects on breeding dispersal. Our data suggest that the proportion of breeding dispersers has increased over time, indicating a density‐dependent component in nest‐site fidelity that may be linked to increased competition.     

Diffusion‐Limited C‐Rate: A Fundamental Principle Quantifying the Intrinsic Limits of Li‐Ion Batteries

The critical challenge for the user acceptance of electric vehicles is the simultaneous improvement of the driving range and fast charging capabilities, which are related to the energy and power density of the storage device. Lithium‐ion batteries (LIBs) are currently the most promising candidate to push electric vehicles toward the mass market. However, they suffer from a tradeoff between energy and power density, forbidding arbitrary combinations of high storage capacity and fast charging capability. Herein, a simple electrochemical principle describing the intrinsic limits of LIBs is reported. It is deduced that the tradeoff between energy and power density originates from diffusion limitations in the electrolyte. The electrochemical approach of diffusion‐limited current density is adapted to porous Li‐ion insertion electrodes, resulting in the “diffusion‐limited C‐rate” (DLC). The theoretical considerations are in excellent agreement with experimentally observed rate limitations of a large number of electrodes with different active materials and varying design parameters. While the C‐rate drawn from an LIB cannot be higher than the DLC without significant capacity decline, parameter variations that improve the DLC reduce the nominal specific capacity. This relationship makes the DLC a fundamental quantity revealing the most expedient optimization approaches and promising directions for future battery research and development.     

Density‐dependent and density‐independent drivers of population change in Barton Springs salamanders

Understanding population change is essential for conservation of imperiled species, such as amphibians. Worldwide amphibian declines have provided an impetus for investigating their population dynamics, which can involve both extrinsic (density‐independent) and intrinsic (density‐dependent) drivers acting differentially across multiple life stages or age classes. In this study, we examined the population dynamics of the endangered Barton Springs Salamander (Eurycea sosorum) using data from a long‐term monitoring program. We were interested in understanding both the potential environmental drivers (density‐independent factors) and demographic factors (interactions among size classes, negative density dependence) to better inform conservation and management activities. We used data from three different monitoring regimes and multivariate autoregressive state‐space models to quantify environmental effects (seasonality, discharge, algae, and sediment cover), intraspecific interactions among three size classes, and intra‐class density dependence. Results from our primary data set revealed similar patterns among sites and size classes and were corroborated by our out‐of‐sample data. Cross‐correlation analysis showed juvenile abundance was most strongly correlated with a 9‐month lag in aquifer discharge, which we suspect is related to inputs of organic carbon into the aquifer. However, sedimentation limited juvenile abundance at the surface, emphasizing the importance of continued sediment management. Recruitment from juveniles to the sub‐adult size class was evident, but negative density‐dependent feedback ultimately regulated each size class. Negative density dependence may be an encouraging sign for the conservation of E. sosorum because populations that can reach carrying capacity are less likely to go extinct compared to unregulated populations far below their carrying capacity. However, periodic population declines coupled with apparent migration into the aquifer complicate assessments of species status. Although both density‐dependent and density‐independent drivers of population change are not always apparent in time series of animal populations, both have important implications for conservation and management of E. sosorum.     

A practical approach to the study of spatial structure in simple cases of heterogeneous vegetation

Abstract. Spatial heterogeneity is a characteristic of most natural ecosystems which is difficult to handle analytically, particularly in the absence of knowledge about the exogenous factors responsible for this heterogeneity. While classical methods for analysis of spatial point patterns usually require the hypothesis of homogeneity, we present a practical approach for partitioning heterogeneous vegetation plots into homogeneous subplots in simple cases of heterogeneity without drastically reducing the data. It is based on the detection of endogenous variations of the pattern using local density and second‐order local neighbour density functions that allow delineation of irregularly shaped subplots that could be considered as internally homogeneous. Spatial statistics, such as Ripley's K‐function adapted to analyse plots of irregular shape, can then be computed for each of the homogeneous subplots. Two applications to forest ecological field data demonstrate that the method, addressed to ecologists, can avoid misinterpretations of the spatial structure of heterogeneous vegetation stands.     

Discovery of Calcium‐Metal Alloy Anodes for Reversible Ca‐Ion Batteries

Ca‐ion batteries (CIBs) show promise to achieve the high energy density required by emerging applications like electric vehicles because of their potentially improved capacities and high operating voltages. The development of CIBs is hindered by the failure of traditional graphite and calcium metal anodes due to the intercalation difficulty and the lack of efficient electrolytes. Recently, a high voltage (4.45 V) CIB cell using Sn as the anode has been reported to achieve a remarkable cyclability (>300 cycles). The calciation of Sn is observed to end at Ca₇Sn₆, which is surprising, since higher Ca‐content compounds are known (e.g., Ca₂Sn). Here, the Sn electrochemical calciation reaction process is investigated computationally and the reaction driving force as a function of Ca content is explored using density functional theory (DFT) calculations. This exploration allows the identification of threshold voltages which govern the limits of the calciation process. This information is then used to design a four‐step screening strategy and high‐throughput DFT is utilized to search for anode materials with higher properties. Many metalloids (Si, Sb, Ge), (post‐)transition metals (Al, Pb, Cu, Cd, CdCu₂) are predicted to be promising inexpensive anode candidates and warrant further experimental investigations.     

Proteomic analysis of human very low-density lipoprotein by two-dimensional gel electrophoresis and MALDI-TOF/TOF

Biochemical studies of lipoproteins have shed light on their composition, highly contributing to the comprehension of their function. Due to the complexity of their structure, however, an in-depth structural analysis, in terms of components and PTMs, may still unravel important players in physiological and pathological processes of lipid metabolism. In this study, we performed a protein map of very low-density lipoprotein (VLDL) using a 2-DE MALDI-TOF/TOF proteomic approach. Several VLDL-associated apolipoproteins were identified, including five isoforms of apoE, three isoforms of apoC-IV, and one isoform each of apoC-III, apoM, apoA-I, and apoA-IV. Notably, we also identified seven isoforms of apoL-I and two isoforms of prenylcysteine lyase as new VLDL-associated proteins. Furthermore, we were able to identify PTM of apoE, which was found to be differently O-glycosylated at Thr212 residue, and PTM of apoL-I which we described, for the first time, to be phosphorylated at Ser296. While the physiological relevance of our finding remains to be assessed, we believe that our results will be useful as reference for future studies of VLDL structure in specific physiopathological conditions.     

Analytical quantification of low‐density lipoprotein using europium tetracycline indicator

Low‐density lipoprotein (LDL) is known as ‘bad’ cholesterol. If too much LDL circulates in the blood it can be retained in the walls of the arteries, causing atherosclerosis. In this paper we showed an alternative method to quantify LDL using the europium tetracycline (EuTc) indicator. The optical properties of the EuTc complex were investigated in aqueous solutions containing LDL. An enhancement was observed of the europium luminescence in the solutions with LDL compared those without the lipoprotein. A method to quantify the amount of LDL in a sample, based on EuTc enhanced luminescence, is proposed. The enhancement mechanism is also discussed. Copyright © 2009 John Wiley & Sons, Ltd.     

Controlled Atomic Solubility in Mn‐Rich Composite Material to Achieve Superior Electrochemical Performance for Li‐Ion Batteries

The quest for high energy density and high power density electrode materials for lithium‐ion batteries has been intensified to meet strongly growing demand for powering electric vehicles. Conventional layered oxides such as Co‐rich LiCoO₂ and Ni‐rich Li(Ni_xMn_yCo_z)O₂ that rely on only transition metal redox reaction have been faced with growing constraints due to soaring price on cobalt. Therefore, Mn‐rich electrode materials excluding cobalt would be desirable with respect to available resources and low cost. Here, the strategy of achieving both high energy density and high power density in Mn‐rich electrode materials by controlling the solubility of atoms between phases in a composite is reported. The resulting Mn‐rich material that is composed of defective spinel phase and partially cation‐disordered layered phase can achieve the highest energy density, ≈1100 W h kg^?1 with superior power capability up to 10C rate (3 A g^?1) among other reported Mn‐rich materials. This approach provides new opportunities to design Mn‐rich electrode materials that can achieve high energy density and high power density for Li‐ion batteries.     

Addressing the yield by density interaction is a prerequisite to bridge the yield gap of rain‐fed wheat

Environmental variability induced by climate change is connected with inter‐annual variation in grain yield of rain‐fed wheat. Density‐dependent cultivars, relying on high populations, usually vary in optimum population. The optimum population is primarily affected by the water regime, while sowing date, heat, terminal drought, frost and type of soil are also indicators. These forces make it difficult to estimate optimum population on the basis of the expected yield level. Furthermore, accounting for the difficulty in foreseeing long‐term weather by variation in the planting versus seeding ratio, an appropriate population might be hard to establish and thus, harvested yield lags behind the highest possible yield. The greater the reliance on high populations, the larger the potential level of this gap and poor yield performance of individual plants is the root cause. Thus, while for drought‐prone environments cultivation at lower populations is prudent, cultivars that fall short of efficient resource capture at the single‐plant level demand much higher populations for seasons with adequate rainfalls. Therefore, flexible density‐independent cultivars performing well at wide range of populations are imperative to meet the future demands in the matter of sustainability and food adequacy. The goal appears attainable through improvement of the single‐plant performance, and the implementation of breeding for yield compensation components offers such a possibility.     

Polyoxometalate‐Derived Ultrasmall Pt2W/WO3 Heterostructure Outperforms Platinum for Large‐Current‐Density H2 Evolution

Platinum (Pt)‐based catalysts with high Pt utilization efficiency for efficient H₂ evolution are attracting extensive attention to meet the issues of energy exhaustion and environmental pollution. Herein, a one‐step electrochemical method is demonstrated to construct ultrafine heterostructure Pt₂W/WO₃ on reduced graphene oxide (RGO) by injecting multielectrons into the Preyssler anion [NaP₅W₃₀O₁₁₀]^14? to codeposit with anodic deliquescent Pt cations. The resulting Pt₂W/WO₃/RGO shows much higher performance than that of commercial Pt catalysts for large‐current‐density H₂ evolution, which can deliver a large current density of 500 mA cm^?2 with an overpotential of only 394 mV, much lower than that of 20% Pt/C (578 mV). Comparisons with control experiments and density functional theory (DFT) calculations both suggest that the much enhanced activity can be mainly attributed to the synergistic cooperation of different components to drive fast and continuous hydrogen desorption on Pt₂W/WO₃/RGO, while it could not run normally for 20% Pt/C under similar conditions due to the formation of huge bubbles on the electrode surface. The effective integration of high catalytic activity and hydrogen desorption ability into a single material can yield advanced materials for large‐current‐density H₂ evolution with remarkable stability.     

Activity of free‐living subterranean blind mole rats Spalax galili (Rodentia: Spalacidae) in an area of supposed sympatric speciation

Subterranean rodents forage underground, which is energetically costly. Therefore, they can be expected to economize burrowing activity in response to food supply and soil characteristics. We analyzed the activity of radio‐tracked blind mole rats, Spalax galili, on a locality sharply subdivided into harder but relatively food‐rich, basaltic soil and softer, relatively food‐poor rendzina. It was recently proposed that the mole rats in this locality are undergoing sympatric ecological speciation. We predicted that mole rats from basaltic soil would be less active than those from rendzina as a result of the reduced need for burrowing to reach food. By contrast to our predictions, mole rats from basaltic soil were more frequently located outside the nest and observed pushing soil above ground. We suggest that this is a result of territorial behaviour due to high population density. All mole rats exhibited a unimodal daily activity pattern likely related to temperature. Large males had large but gradually decreasing home‐ranges, likely indicating the end of the mating season. We conclude that the ecological differences between the habitats cause behavioural differences in the mole rats, which indicates different selection pressures. The genetic divergence previously found between the populations might have arisen via density‐dependent selection.     

High‐density Lipoprotein Apolipoprotein A‐I Kinetics in Obesity

Objective: Low plasma concentrations of high‐density lipoprotein (HDL)‐cholesterol and apolipoprotein A‐I (apoA‐I) are independent predictors of coronary artery disease and are often associated with obesity and the metabolic syndrome. However, the underlying kinetic determinants of HDL metabolism are not well understood. Research Methods and Procedures: We pooled data from 13 stable isotope studies to investigate the kinetic determinants of apoA‐I concentrations in lean and overweight—obese individuals. We also examined the associations of HDL kinetics with age, sex, BMI, fasting plasma glucose, fasting insulin, Homeostasis Model Assessment score, and concentrations of apoA‐I, triglycerides, HDL‐cholesterol and low‐density lipoprotein‐cholesterol. Results: Compared with lean individuals, overweight—obese individuals had significantly higher HDL apoA‐I fractional catabolic rate (0.21 ± 0.01 vs. 0.33 ± 0.01 pools/d; p < 0.001) and production rate (PR; 11.3 ± 4.4 vs. 15.8 ± 2.77 mg/kg per day; p = 0.001). In the lean group, HDL apoA‐I PR was significantly associated with apoA‐I concentration (r = 0.455, p = 0.004), whereas in the overweight—obese group, both HDL apoA‐I fractional catabolic rate (r = ?0.396, p = 0.050) and HDL apoA‐I PR (r = 0.399, p = 0.048) were significantly associated with apoA‐I concentration. After adjustment for fasting insulin or Homeostasis Model Assessment score, HDL apoA‐I PR was an independent predictor of apoA‐I concentration. Discussion: In overweight—obese subjects, hypercatabolism of apoA‐I is paralleled by an increased production of apoA‐I, with HDL apoA‐I PR being the stronger determinant of apoA‐I concentration. This could have therapeutic implications for the management of dyslipidemia in individuals with low plasma HDL‐cholesterol.     

Spatial distribution of nests constrains the strength of sexual selection in a warbler

In socially monogamous species, extra‐pair paternity may increase the strength of intersexual selection by allowing males with preferred phenotypes to monopolize matings. Several studies have found relationships between male signals and extra‐pair mating, but many others fail to explain variation in extra‐pair mating success. A greater appreciation for the role that ecological contingencies play in structuring behavioural processes may help to reconcile contradictory results. We studied extra‐pair mating in a spatial context in the common yellowthroat (Geothlypis trichas), a territorial wood warbler. Over the course of 6 years, we observed 158 breeding attempts by 99 males, resulting in a total of 369 nests and 520 sampled nestlings. The spatial distribution of territories varied greatly, with males having between 0 and 10 close neighbours and between three and 39 neighbouring nestlings close enough to represent extra‐pair siring opportunities. Both within‐pair and extra‐pair reproductive success increased with breeding density, but the opportunity for sexual selection and strength of selection varied with density. Total variance in reproductive success was highest at low density and was mostly explained by variation in within‐pair success. In contrast, at high density, both within‐pair and extra‐pair successes contributed substantially to variance in reproductive success. The relationships between plumage and extra‐pair mating also varied by density; plumage was under strong sexual selection via extra‐pair mating success at high density, but no selection was detected at low density. Thus, ecological factors that structure social interactions can drive patterns of sexual selection by facilitating or constraining the expression of mating preferences.     

Condition‐dependent movement and dispersal in experimental metacommunities

Dispersal and the underlying movement behaviour are processes of pivotal importance for understanding and predicting metapopulation and metacommunity dynamics. Generally, dispersal decisions are condition‐dependent and rely on information in the broad sense, like the presence of conspecifics. However, studies on metacommunities that include interspecific interactions generally disregard condition‐dependence. Therefore, it remains unclear whether and how dispersal in metacommunities is condition‐dependent and whether rules derived from single‐species contexts can be scaled up to (meta)communities. Using experimental protist metacommunities, we show how dispersal and movement depend on and are adjusted by the strength of interspecific interactions. We found that the predicting movement and dispersal in metacommunities requires knowledge on behavioural responses to intra‐ and interspecific interaction strengths. Consequently, metacommunity dynamics inferred directly from single‐species metapopulations without taking interspecific interactions into account are likely flawed. Our work identifies the significance of condition‐dependence for understanding metacommunity dynamics, stability and the coexistence and distribution of species.