International review of natural family planning

. Linear constraint databases (LCDBs) extend relational databases to include linear arithmetic constraints in both relations and queries. A LCDB can also be viewed as a powerful extension of linear programming (LP) where the system of constraints is generalized to a database containing constraints and the objective function is generalized to a relational query containing constraints. Our major concern is query optimization in LCDBs. Traditional database approaches are not adequate for combination with LP technology. Instead, we propose a new query optimization approach, based on statistical estimations and iterated trials of potentially better evaluation plans. The resulting algorithms are not only effective on LCDBs, but also applicable to existing query languages. A number of specific constraint algebra algorithms are also developed: select-project-join for two relations, constraint sortjoin and constraint multi-join. 1. Introduction Linear programming/linear constraints is a tech..

Carbon sequestration in clay and silt fractions of Brazilian soils under conventional and no-tillage systems

The capacity of soils to sequestrate carbon (C) is mainly related to the formation of organo-mineral complexes. In this study, we investigated the influence of soil management systems on the C retention capacity of soil with an emphasis on the silt and clay fractions of two subtropical soils with different mineralogy and climate. Samples from a Humic Hapludox and a Rhodic Hapludox, clayey soils cultivated for approximately 30 years under no-tillage (NT) and conventional tillage (CT) were collected from six layers distributed within 100-cm soil depth from each site and from an adjacent native forest. After the removal of particulate organic matter (POM), the suspension (<53 μm) was sonicated, the silt and clay fractions were separated in accordance with Stokes' law and the carbon content of whole soil and physical fractions was determined. In the Humic Hapludox, the clay and silt fractions under NT showed a higher maximum C retention (72 and 52 g kg−1, respectively) in comparison to those under CT (54 and 38 g kg−1, respectively). Moreover, the C concentration increase in both fractions under NT occurred mainly in the topsoil (up to 5 cm). The C retention in physical fractions of Rhodic Hapludox varied from 25 to 32 g kg−1, and no difference was observed whether under an NT or a CT management system. The predominance of goethite and gibbsite in the Humic Hapludox, as well as its exposure to a colder climate, may have contributed to its greater C retention capacity. In addition to the organo-mineral interaction, a mechanism of organic matter self-assemblage, enhanced by longer periods of soil non-disturbance, seems to have contributed to the carbon stabilization in both soils

Effect of Using the HEART Score in Patients With Chest Pain in the Emergency Department: A Stepped-Wedge, Cluster Randomized Trial

Item does not contain fulltextBackground: The HEART (History, Electrocardiogram, Age, Risk factors, and initial Troponin) score is an easy-to-apply instrument to stratify patients with chest pain according to their short-term risk for major adverse cardiac events (MACEs), but its effect on daily practice is unknown. Objective: To measure the effect of use of the HEART score on patient outcomes and use of health care resources. Design: Stepped-wedge, cluster randomized trial. (ClinicalTrials.gov: NCT01756846). Setting: Emergency departments in 9 Dutch hospitals. Patients: Unselected patients with chest pain presenting at emergency departments in 2013 and 2014. Intervention: All hospitals started with usual care. Every 6 weeks, 1 hospital was randomly assigned to switch to "HEART care," during which physicians calculated the HEART score to guide patient management. Measurements: For safety, a noninferiority margin of a 3.0% absolute increase in MACEs within 6 weeks was set. Other outcomes included use of health care resources, quality of life, and cost-effectiveness. Results: A total of 3648 patients were included (1827 receiving usual care and 1821 receiving HEART care). Six-week incidence of MACEs during HEART care was 1.3% lower than during usual care (upper limit of the 1-sided 95% CI, 2.1% [within the noninferiority margin of 3.0%]). In low-risk patients, incidence of MACEs was 2.0% (95% CI, 1.2% to 3.3%). No statistically significant differences in early discharge, readmissions, recurrent emergency department visits, outpatient visits, or visits to general practitioners were observed. Limitation: Physicians were hesitant to refrain from admission and diagnostic tests in patients classified as low risk by the HEART score. Conclusion: Using the HEART score during initial assessment of patients with chest pain is safe, but the effect on health care resources is limited, possibly due to nonadherence to management recommendations. Primary Funding Source: Netherlands Organisation for Health Research and Development

Applying the aboveground-belowground interaction concept in agriculture: Spatio-temporal scales matter

Interactions between aboveground and belowground organisms are important drivers of plant growth and performance in natural ecosystems. Making practical use of such above-belowground biotic interactions offers important opportunities for enhancing the sustainability of agriculture, as it could favor crop growth, nutrient supply, and defense against biotic and abiotic stresses. However, the operation of above-and belowground organisms at different spatial and temporal scales provides important challenges for application in agriculture. Aboveground organisms, such as herbivores and pollinators, operate at spatial scales that exceed individual fields and are highly variable in abundance within growing seasons. In contrast, pathogenic, symbiotic, and decomposer soil biota operate at more localized spatial scales from individual plants to patches of square meters, however, they generate legacy effects on plant performance that may last from single to multiple years. The challenge is to promote pollinators and suppress pests at the landscape and field scale, while creating positive legacy effects of local plant-soil interactions for next generations of plants. Here, we explore the possibilities to improve utilization of above-belowground interactions in agro-ecosystems by considering spatio-temporal scales at which aboveground and belowground organisms operate. We identified that successful integration of above-belowground biotic interactions initially requires developing crop rotations and intercropping systems that create positive local soil legacy effects for neighboring as well subsequent crops. These configurations may then be used as building blocks to design landscapes that accommodate beneficial aboveground communities with respect to their required resources. For successful adoption of above-belowground interactions in agriculture there is a need for context-specific solutions, as well as sound socio-economic embedding.</p