Tit for Tat: sticklebacks (Gasterosteus aculeatus) ‘trusting' a cooperating partner

Individual three-spined sticklebacks (Gasterosteus aculeatus) moved closer to a predatory trout when a ‘cooperator' stickleback, which the test fish could see through a one-way mirror, swam up to the predator than when a ‘defector' stickleback appeared to swim only half as close to the predator. After four training runs with both types of partners, the former cooperator also defected. The test fish continued to move closer to the predator in the presence of the former cooperator even though both the former cooperator and the defector now appeared to stop in their approach to the predator at the same distance. This shows that probable partners build up trus

Cadmium Malonate Complexation in Aqueous Sodium Trifluoromethanesulfonate Media to 75°C; Including Dissociation Quotients of Malonic Acid

The molal formation quotients for cadmium-malonate complexes were measured potentiometrically from 5 to 75°C, at ionic strengths of 0.1, 0.3, 0.6 and 1.0 molal in aqueous sodium trifluoromethanesulfonate (NaTf) media. In addition, the stepwise dissociation quotients for malomc acid were measured in the same medium from 5 to 100°C, at ionic strengths of 0.1, 0.3, 0.6, and 1.0 molal by the same method. The dissociation quotients for malonic acid were modeled as a function of temperature and ionic strength with empirical equations formulated such that the equilibrium constants at infinite dilution were consistent, within the error estimates, with the malonic acid dissociation constants obtained in NaCl media. The equilibrium constants calculated for the dissociation of malonic acid at 25°C and infinite dilution are log K1a = -2.86 ± 0.01 and log K2a = -5.71 ± 0.01. A single Cd-malonate species, CdCH2C2O4, was identified from the complexation study and the formation quotients for this species were also modeled as a function of temperature and ionic strength. Thermodynamic parameters obtained by differentiating the equation with respect to temperature for the formation of CdCH2C2O4 at 25°C and infinite dilution are: log K = 3.45 ± 0.09, ΔH° = 7 ± 6 kJ-mol-1, ΔS° = 91 ± 22 J-K-1-mol-1, and ΔC°p = 400 ± 300J-K-1-mol-1

A Population Study of 5 to 15 Year Olds: Full Time Maternal Employment not Associated with High BMI. The Importance of Screen-Based Activity, Reading for Pleasure and Sleep Duration in Children’s BMI

To describe the relationship between maternal full time employment and health-related and demographic variables associated with children aged 5–15 years, and the factors associated with child overweight/obesity. Data from a chronic disease and risk factor surveillance system were limited to children aged 5–15 years whose mothers responded on their behalf (n = 641). Univariate/multivariate analyses described the differences between mothers who did and did not work full time. The same data were analysed comparing children who are overweight/obese against those with a normal BMI. The children of mothers who worked full time are more likely to be older, live in a household with a higher household income, be an only child or have one sibling or other child in the household, have a sole mother family structure and not spend any time reading for pleasure. No relationship was found between maternal employment and BMI. Compared with children of normal weight, those who were overweight/obese were more likely to spend no time studying, spend more than 2 h per day in screen-based activity and sleep less than 10 h per night. Child BMI status was not related to maternal employment. Although this analysis included eight diet related variables none proved to be significant in the final models.This study has shown that mothers’ working status is not related to children’s BMI. The relationship between overweight/obesity of children and high levels of screen-based activity, low levels of studying, and short sleep duration suggests a need for better knowledge and understanding of sedentary behaviours of children

Making sense of thought leadership

Many corporations feel that they should be developing a thought leadership strategy. However, when asked what thought leadership actually means or entails, most managers immediately falter in providing an explanation. So, what is thought leadership, why is it important, and how can companies pursue it

Life and Liesegang: Outcrop-Scale Microbially Induced Diagenetic Structures and Geochemical Self-Organization Phenomena Produced by Oxidation of Reduced Iron

The Kanab Wonderstone is sandstone (Shinarump Member, Chinle Formation) that is cemented and stained with iron oxide. The iron-oxide cementation and staining in these rocks have been considered examples of the Liesegang phenomenon, but we will show that they comprise a microbially induced structure. The spacing of bands of iron-oxide stain follow the Jablczynski spacing law (wherein the spacing between bands of iron-oxide stain increases as one traverses a series of bands) characteristic of Liesegang. Bands of iron-oxide cement exhibit more variable spacing and exhibit a weak but significant correlation between band thickness and distance between bands of cement. The pore-filling cement contains morphotypes that are similar in size and habit to those exhibited by microaerophilic iron-oxidizing bacteria. Other disseminated iron-oxide mineralization occurs as rhombohedra interpreted to be pseudomorphs after siderite. We interpret the cement to be produced by microbially mediated oxidation of siderite (a typical early diagenetic mineral in fluvial sandstones). Iron-oxidizing bacteria colonized the redox interface between siderite-cemented sand and porous sandstone. Microbes oxidized aqueous Fe(II), generating acid that caused siderite dissolution. The iron-oxide cement is the microbial product of a geochemical drive for organization; whereas the iron-oxide stain is true Liesegang. Together, they comprise a distinctive microbially induced structure with high preservation potential. Key Words: Biosignatures—Iron oxides—Diagenesis—Iron-oxidizing bacteria—Shinarump

3D macro- and microfabric analyses of Neoproterozoic diamictites from the Valjean Hills, California (United States)

The Cryogenian interval (720–635 Ma) is famous for a rich archive of diamictites, many of which were deposited during glaciations. Classic examples are exposed in the Kingston Peak Formation of the Valjean Hills, near Death Valley (United States), with previous work pointing to multiple glacial cycles in other outcrop belts. Within any glacial period, diamictites are widespread, and in addition, their mechanics of deposition are highly variable. Some are massive in appearance at outcrop or in hand specimens and apparently lack any information that allows their mode of emplacement to be elucidated. Yet, the correct interpretation for deep-time successions in this area is especially important, since it is debated whether the diamictites are either associated with a tectonically driven origin, associated with rifting at the south-western Laurentian margin alongside slope-controlled gravitational mass movement, or predominantly deposited as (sub)glacial diamictites. In this paper, we demonstrate how diamictite texture can be objectively quantified based on clast orientations, at both macroscale and microscale (micromorphology), guiding interpretations. Our method is based on a technique used for Quaternary sediments, by mapping the apparent longest axes of skeleton grains (ranging from fine-grained sand to fine-grained pebbles) in oriented thin sections and reconstructing their microfabric in a 3D space coupled with macrofabric data for each diamictite. In this way, we could identify a bimodal signal in the orientation of the longest axes for each sample. Evidence for shearing and soft sediment deformation supports either subaqueous or subglacial deposition with deformation induced by basal sliding with a paleoflow directed toward the southeast. Our combined approach of micro- and macrofabric analyses can also encourage acquiring accurate fabric data for seemingly structureless diamictites from other deep-time rock archives in an objective manner

Context-Aware Interaction Approach to Handle Users Local Contexts in Web 2.0

International audienceUsers sharing and authoring of Web contents via different Web sites is the main idea of the Web 2.0. However, Web users belong to different communities and follow their own semantics (referred to as contexts) to represent and interpret Web contents. Therefore, they encounter discrepancies when they have to interpret Web contents authored by different persons. This paper proposes a context-aware interaction approach that helps Web authors annotate Web contents with their local context information, so that it becomes possible for Web browsers to personalize these contents according to different users’ local contexts

The Composition of Cosmic Rays at the Knee

The observation of a small change in spectral slope, or 'knee' in the fluxes of cosmic rays near energies 10^15 eV has caused much speculation since its discovery over 40 years ago. The origin of this feature remains unknown. A small workshop to review some modern experimental measurements of this region was held at the Adler Planetarium in Chicago, USA in June 2000. This paper summarizes the results presented at this workshop and the discussion of their interpretation in the context of hadronic models of atmospheric airshowers.Comment: 36 pages, 10 figure

Simultaneous X-Ray and TeV Gamma-Ray Observations of the TeV Blazar Markarian 421 during February and May 2000

In this paper we present the results of simultaneous observations of the TeV blazar Markarian 421 (Mrk 421) at X-ray and TeV Gamma-ray energies with the Rossi X-Ray Timing Explorer (RXTE) and the stereoscopic Cherenkov Telescope system of the HEGRA (High Energy Gamma Ray Astronomy) experiment, respectively. The source was monitored from February 2nd to February 16th and from May 3rd to May 8th, 2000. We discuss in detail the temporal and spectral properties of the source. Remarkably, the TeV observations of February 7th/8th showed statistically significant evidence for substantial TeV flux variability on 30 min time scale. We show the results of modeling the data with a time dependent homogeneous Synchrotron Self-Compton (SSC) model. The X-ray and TeV gamma-ray emission strengths and energy spectra together with the rapid flux variability strongly suggest that the emission volume is approaching the observer with a Doppler factor of 50 or higher. The different flux variability time scales observed at X-rays and TeV Gamma-rays indicate that a more detailed analysis will require inhomogeneous models with several emission zones.Comment: Accepted for Publication in ApJ, 21 Pages, 5 Figure