255 research outputs found
Guide to best practices for ocean CO2 measurements
CHAP 1 - Introduction to the Guide
CHAP 2 - Solution chemistry of carbon dioxide in sea water
CHAP 3 - Quality assurance
CHAP 4 - Recommended standard operating procedures (SOPs)
SOP 1 - Water sampling for the parameters of the oceanic carbon dioxide system
SOP 2 - Determination of total dissolved inorganic carbon in sea water
SOP 3a - Determination of total alkalinity in sea water using a closed-cell titration
SOP 3b - Determination of total alkalinity in sea water using an open-cell titration
SOP 4 - Determination of p(CO2) in air that is in equilibrium with a discrete sample of sea water
SOP 5 - Determination of p(CO2) in air that is in equilibrium with a continuous stream of sea water
SOP 6a - Determination of the pH of sea water using a glass/reference electrode cell
SOP 6b - Determination of the pH of sea water using the indicator dye m-cresol purple
SOP 7 - Determination of dissolved organic carbon and total dissolved nitrogen in sea water
SOP 7 en Español - Determinacion de carbono organico disuelto y nitrogeno total disuelto en agua de mar
SOP 11 - Gravimetric calibration of the volume of a gas loop using water
SOP 12 - Gravimetric calibration of volume delivered using water
SOP 13 - Gravimetric calibration of volume contained using water
SOP 14 - Procedure for preparing sodium carbonate solutions for the calibration of coulometric CT measurements
SOP 21 - Applying air buoyancy corrections
SOP 22 - Preparation of control charts
SOP 23 - Statistical techniques used in quality assessment
SOP 24 - Calculation of the fugacity of carbon dioxide in the pure gas or in air
CHAP 5 - Physical and thermodynamic data
Errata - to the hard copy of the Guide to best practices for ocean CO2 measurement
Tillage-induced spatial distribution of surface crusts on a sandy paleustult from Togo
The spatial distribution of crusts in coarse-textured soils and the processes affecting it are poorly documented, despite the potential impact of crusts on water infiltration. This study addresses the influence of tillage-induced microrelief on the morphology and spatial distribution of surface crusts in an oxic paleustult from southern Togo (West Africa). Replicate 1 m2 plots were exposed to 217 mm of natural rainfall during a 6-wk period, during which the surface topography was measured three times. Subsequently, 24 undisturbed crust samples were used for micromorphological analysis. The crusts exhibited a range of morphologies but were nevertheless adequately mapped and characterized according to two main types. Type 1 crusts (= runoff crusts) showed several superposed clay bands, 100 to 500 mm thick, buried within a micromass-depleted sand layer lesser or equal to 12 mm thick. Type 2 crusts (= erosion crusts) had an exposed clay band a few tenths of a millimeter thick. The spatial distribution of crusts at the time of sampling appeared better correlated with the initial than with the final microtopography of the plots. These findings suggest that crust distribution should be regarded as history dependent and that erosion and deposition processes largely governed the development of the crusts. This latter aspect is in agreement with the recent crust genesis model of Valentin and Bresson, as is the fact that clay bands in our plots were laterally continuous at all observational scales lesser or equal to 0.1 m. Other mechanisms proposed in the literature for the developement of clay bands did not seem able to account adequately for the observed pattern. (Résumé d'auteur
HCI and environmental public policy:opportunities for engagement
This note discusses opportunities for the HCI community to engage with environmental public policy. It draws on insights and observations made during the primary author’s recent work for a policy unit at Global Affairs Canada, which is a federal ministry of the Government of Canada. During that work, the primary author identified several domains of environmental public policy that are of direct relevance to the HCI commu- nity. This note contributes a preliminary discussion of how, why, with whom, and in what capacity HCI researchers and practitioners might engage with three types of environmental public policy: climate change, waste electrical and electronic equipment, and green ICT procurement policies. This builds on existing public policy and environmental knowledge within the HCI community and responds directly to calls from some members to engage with environmental public policy
Enhanced Nonperturbative Effects in Z Decays to Hadrons
We use soft collinear effective field theory (SCET) to study nonperturbative
strong interaction effects in Z decays to hadronic final states that are
enhanced in corners of phase space. These occur, for example, in the jet energy
distribution for two jet events near E_J=M_Z/2, the thrust distribution near
unity and the jet invariant mass distribution near zero. The extent to which
such nonperturbative effects for different observables are related is
discussed.Comment: 17 pages. Paper reorganized, and more discussion and results include
Chaotic scalar fields as models for dark energy
We consider stochastically quantized self-interacting scalar fields as
suitable models to generate dark energy in the universe. Second quantization
effects lead to new and unexpected phenomena is the self interaction strength
is strong. The stochastically quantized dynamics can degenerate to a chaotic
dynamics conjugated to a Bernoulli shift in fictitious time, and the right
amount of vacuum energy density can be generated without fine tuning. It is
numerically observed that the scalar field dynamics distinguishes fundamental
parameters such as the electroweak and strong coupling constants as
corresponding to local minima in the dark energy landscape. Chaotic fields can
offer possible solutions to the cosmological coincidence problem, as well as to
the problem of uniqueness of vacua.Comment: 30 pages, 3 figures. Replaced by final version accepted by Phys. Rev.
Equivalence between Bell inequalities and quantum Minority game
We show that, for a continuous set of entangled four-partite states, the task
of maximizing the payoff in the symmetric-strategy four-player quantum Minority
game is equivalent to maximizing the violation of a four-particle Bell
inequality with each observer choosing the same set of two dichotomic
observables. We conclude the existence of direct correspondences between (i)
the payoff rule and Bell inequalities, and (ii) the strategy and the choice of
measured observables in evaluating these Bell inequalities. We also show that
such a correspondence between Bell polynomials (in a single plane) and
four-player, symmetric, binary-choice quantum games is unique to the
four-player quantum Minority game and its "anti-Minority" version. This
indicates that the four-player Minority game not only plays a special role
among quantum games but also in studies of Bell-type quantum nonlocality.Comment: v1 4 pages ReTeX, 2 figures (1 EPS); v2 11 pages LateX, 2 figures,
changes to format, minor changes to wording (including title) and one new
finding added on uniqueness of resul
Extreme Ultra-Violet Spectroscopy of the Lower Solar Atmosphere During Solar Flares
The extreme ultraviolet portion of the solar spectrum contains a wealth of
diagnostic tools for probing the lower solar atmosphere in response to an
injection of energy, particularly during the impulsive phase of solar flares.
These include temperature and density sensitive line ratios, Doppler shifted
emission lines and nonthermal broadening, abundance measurements, differential
emission measure profiles, and continuum temperatures and energetics, among
others. In this paper I shall review some of the advances made in recent years
using these techniques, focusing primarily on studies that have utilized data
from Hinode/EIS and SDO/EVE, while also providing some historical background
and a summary of future spectroscopic instrumentation.Comment: 34 pages, 8 figures. Submitted to Solar Physics as part of the
Topical Issue on Solar and Stellar Flare
Acculturation Influences Postpartum Eating, Activity, and Weight Retention in Low-Income Hispanic Women
Background: Low-income Hispanic women experience elevated rates of high postpartum weight retention (PPWR), which is an independent risk factor for lifetime obesity. Sociocultural factors might play an important role among Hispanic women; however, very few studies have examined this association. Objective: The purpose of our study was to examine the associations between acculturation and maternal diet, physical activity, and PPWR. Design: This is a cross-sectional study of baseline data from 282 Hispanic women participating in the FitMoms/Mamás Activas study, a randomized controlled trial examining the impact of primarily an internet-based weight control program, in reducing PPWR among low-income women. We performed multivariable linear regression to examine the association of acculturation with diet quality, physical activity, and PPWR at study entry. Results: A total of 213 (76%) women had acculturation scores reflecting Mexican orientation or bicultural orientation, whereas 69 (24%) had scores that represented assimilation to Anglo culture. Women who were more acculturated had lower intakes of fruits and vegetables, lower HEI scores, and lower physical activity levels than women who were less acculturated (p < 0.05). We found an association between acculturation and PPWR in that for every 1-unit increase in acculturation score, PPWR increased, on average, by 0.80 kg. Conclusion: Higher acculturation was associated with poorer diet and physical activity behaviors and greater PPWR
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