192 research outputs found
Population ecology and functioning of Enchytraeidae in some arable farming systems
The population ecology of Enchytraeidae, and their functioning, were studied in some arable farming systems and in laboratory experiments. The systems studied consisted of a 'conventional' (high input of energy and matter) and several 'integrated' (reduced input of energy and matter) systems. Emphasis was given to population dynamics and the role of Enchytraeidae in nutrient cycling and soil structure evolution.Mean yearly enchytraeid abundance and biomass in the systems studied ranged from 11000 ind/m 2to 43000 ind/m 2, and from 0.08 g C/m 2to 0.42 g C/m 2, respectively. It was calculated that 0.5-3.7% of the yearly organic carbon input was respired by the enchytraeid populations. Yearly nitrogen flux from the populations (through storage in enchytraeid tissue) ranged from 0.19 to 0.60 g/m 2.There were no significant differences between the systems studied as regards population dynamical and production ecological parameters. However, vertical distribution of enchytraeid populations differed markedly between the conventional field and the integrated fields, probably related with differences in soil tillage and the resulting distribution of organic fertilizer and plant residues. These differences in vertical distribution may have consequences for the risk of nutrients leaching from the systems.The impact of enchytraeid activity on soil structure evolution was studied in a field experiment with artificial soil cores, in combination with field observations. It was found that enchytraeid activity produced measurable effects on air permeability, pore size distribution, and distribution of aggregate sizes, probably through selective burrowing and transport of organic besides mineral material.Life-history parameters of Enchytraeus buchholzi, the dominant species at the research site, were determined in a laboratory experiment, and predictions based on the laboratory trials were compared with data on population development under more natural conditions. There were significant discrepancies, indicating an influence of the physiological condition of the experimental animals on the length of the life-cycle in this species
Setting up a new team of support staff for people with mild intellectual disability or borderline intellectual functioning and severe challenging behaviour:A concept mapping study
Background Studies about teams of staff supporting people with intellectual disability have focused on team performance of existing teams. This study aimed to examine important factors in the process of setting up a new team of support staff. Specifically, we considered the process for a team that supports service users with mild intellectual disability or borderline intellectual functioning who display severe challenging behaviour from the orthopedagogical perspective (i.e., with a focus on contextual factors). Method Three participant groups (service users, support staff, and professionals supporting a team) participated in a concept mapping procedure, including generating statements in interviews and focus groups, sorting, and rating. An expert group interpreted the results. Results Important factors to one or more groups were: service users and support staff getting acquainted early, team safety, social support, a shared vision, and a positive reputation of the new home. Conclusions Four core outcomes were addressed that may help service organisations to provide an environment matching the needs of service users who show severe challenging behaviour from the start
Psychomotor therapy targeting anger and aggressive behaviour in individuals with mild or borderline intellectual disabilities:A systematic review
Background: Poor anger regulation is considered a risk factor of aggression in individuals with mild or borderline intellectual disabilities. Psychomotor therapy (PMT) targets anger regulation through body- and movement-oriented interventions. This study aims to inform practitioners on efficacy and research-base of PMT in this population. Method: This systematic review evaluated nine studies which met inclusion criteria in terms of participants, intervention procedures, outcomes and certainty of evidence. Results: Seven studies revealed a substantial reduction of aggressive behaviour or anger. Certainty of evidence was rated inconclusive in most cases due to absence of experimental control. Conclusions: We can conclude that body-oriented PMT, involving progressive relaxation and meditation procedure "Soles of the Feet", is a promising approach. However, the paucity of studies and methodological limitations preclude classifying it as an evidence-based practice. This suggests stronger methodological research and research aimed at PMT's mechanisms of action (e.g., improved interoceptive awareness) is warranted.</p
Life support functies van de bodem: operationalisering t.b.v. het biodiversiteitsbeleid
Ter uitvoering van actiepunt NMW1a uit het Strategisch Plan van Aanpak biodiversiteit (SPA; LNV, VROM, V&W, OCW, EZ, BZ, 1995) en als onderdeel van actie N59 uit het NMP-2, is eerder een studie uitgevoerd naar de mogelijkheden om een indicatorsysteem op te stellen voor biodiversiteit van de bodem in relatie tot Life support functies (LSF). In een pilotproject is het indicatorsysteem vervolgens getest binnen de infrastructuur van het Landelijk Meetnet Bodemkwaliteit (LMB). Het indicatorsysteem, en de daaruit af te leiden bodembiologische indicator, bestaat uit een aantal deelindicatoren. De vragen van het onderzoek waren.- kan de gekozen indicatorset worden toegepast in een meetnet; hebben de deelindicatoren van de set voldoende onderscheidend vermogen; kunnen de resultaten worden ingepast in de huidige diagnostische en prognostische gereedschappen van het RIVM (Natuurplanner en EKI).De resultaten en conclusies uit de pilot zijn in dit beleidsgerichte rapport kort beschreven. Een meer gedetailleerde uitwerking van de onderzoeksresultaten verschijnt in het achtergrond-rapport. De pilot heeft aangetoond dat de geselecteerde deelindicatoren gevoelig en onderscheidend zijn voor verschillende combinaties van bodemtype en landgebruik. Als een mogelijke vorm voor het weergeven van de resultaten behaald met de bodembiologische indicator, is een AMOEBE gemaakt voor graslanden op zeeklei. Hierbij is gebruik gemaakt van een gekozen (voorlopige) referentie. De gegevens zijn verder geaggregeerd tot een Bodemkwaliteitsindex (BKX). Op deze wijze zou aan een ecologische bodembeoordeling vorm gegeven kunnen worden. Door systematisch onderzoek aan LSF-deelindicatoren in het Landelijk Meetnet Bodemkwaliteit (40 locaties per jaar) kan in 5 jaar een database opgebouwd worden waarmee responsrelaties voor bodemeigenschappen, systeemeigen- en systeemvreemde stoffen zijn af te leiden. Hiermee kan een LSF-module (prognostisch instrument) worden opgenomen in een decision support systeem als de Natuurplanne
Deep currents and the eastward salinity tongue in the equatorial Atlantic: Results from an eddy-resolving, primitive equation model
The high-resolution model of the wind-driven and thermohaline circulation in the Atlantic Ocean developed in recent years as a “community modeling effort” for the World Ocean Circulation Experiment is examined for the temporal and spatial structure of the deep equatorial current field and its effect on the spreading of North Atlantic Deep Water (NADW). Under seasonally varying wind forcing, the model reveals a system of basin-wide zonal currents of O(5 cm s−1), alternating east-west, and oscillating at an annual period. The current fluctuations are induced by the seasonal cycle of the wind stress in the equatorial Atlantic and show characteristics of long equatorial Rossby waves with westward phase propagation of about 15 cm s−1. The mean flow in the deep western tropical Atlantic is governed by a deep western boundary current (DWBC) with core velocities of more than 10 cm s−1. Only a small fraction of the DWBC branches off at the equator, with correspondingly low mean eastward currents of only about 1 cm s−1. Despite this weak advection along the equator, a well-developed salinity tongue is observed in the model, which is reminiscent of observed property distributions at the upper NADW level. The model evaluation indicates the salinity pattern to be a result of a balance between mean zonal advection and meridional diffusion of salt. The presence of the zonal current oscillations appears to have no significance for the existence of the salinity tongue
The prevalence and incidence of mental ill-health in adults with autism and intellectual disabilities
The prevalence, and incidence, of mental ill-health in adults with intellectual disabilities and autism were compared with the whole population with intellectual disabilities, and with controls, matched individually for age, gender, ability-level, and Down syndrome. Although the adults with autism had a higher point prevalence of problem behaviours compared with the whole adult population with intellectual disabilities, compared with individually matched controls there was no difference in prevalence, or incidence of either problem behaviours or other mental ill-health. Adults with autism who had problem behaviours were less likely to recover over a two-year period than were their matched controls. Apparent differences in rates of mental ill-health are accounted for by factors other than autism, including Down syndrome and ability level
Predicting procedure duration of colorectal endoscopic submucosal dissection at Western endoscopy centers
Background and study aims Overcoming logistical obstacles for the implementation of colorectal endoscopic submucosal dissection (ESD) requires accurate prediction of procedure times. We aimed to evaluate existing and new prediction models for ESD duration.Patients and methods Records of all consecutive patients who underwent single, non-hybrid colorectal ESDs before 2020 at three Dutch centers were reviewed. The performance of an Eastern prediction model [GIE 2021;94(1):133–144] was assessed in the Dutch cohort. A prediction model for procedure duration was built using multivariable linear regression. The model’s performance was validated using internal validation by bootstrap resampling, internal-external cross-validation and external validation in an independent Swedish ESD cohort.Results A total of 435 colorectal ESDs were analyzed (92% en bloc resections, mean duration 139 minutes, mean tumor size 39 mm). The performance of current unstandardized time scheduling practice was suboptimal (explained variance: R2=27%). We successfully validated the Eastern prediction model for colorectal ESD duration <60 minutes (c-statistic 0.70, 95% CI 0.62–0.77), but this model was limited due to dichotomization of the outcome and a relatively low frequency (14%) of ESDs completed <60 minutes in the Dutch centers. The model was more useful with a dichotomization cut-off of 120 minutes (c-statistic: 0.75; 88% and 17% of “easy” and “very difficult” ESDs completed <120 minutes, respectively). To predict ESD duration as continuous outcome, we developed and validated the six-variable cESD-TIME formula (https://cesdtimeformula.shinyapps.io/calculator/; optimism-corrected R2=61%; R2=66% after recalibration of the slope).Conclusions We provided two useful tools for predicting colorectal ESD duration at Western centers. Further improvements and validations are encouraged with potential local adaptation to optimize time planning
Solving Nonlinear Parabolic Equations by a Strongly Implicit Finite-Difference Scheme
We discuss the numerical solution of nonlinear parabolic partial differential
equations, exhibiting finite speed of propagation, via a strongly implicit
finite-difference scheme with formal truncation error . Our application of interest is the spreading of
viscous gravity currents in the study of which these type of differential
equations arise. Viscous gravity currents are low Reynolds number (viscous
forces dominate inertial forces) flow phenomena in which a dense, viscous fluid
displaces a lighter (usually immiscible) fluid. The fluids may be confined by
the sidewalls of a channel or propagate in an unconfined two-dimensional (or
axisymmetric three-dimensional) geometry. Under the lubrication approximation,
the mathematical description of the spreading of these fluids reduces to
solving the so-called thin-film equation for the current's shape . To
solve such nonlinear parabolic equations we propose a finite-difference scheme
based on the Crank--Nicolson idea. We implement the scheme for problems
involving a single spatial coordinate (i.e., two-dimensional, axisymmetric or
spherically-symmetric three-dimensional currents) on an equispaced but
staggered grid. We benchmark the scheme against analytical solutions and
highlight its strong numerical stability by specifically considering the
spreading of non-Newtonian power-law fluids in a variable-width confined
channel-like geometry (a "Hele-Shaw cell") subject to a given mass
conservation/balance constraint. We show that this constraint can be
implemented by re-expressing it as nonlinear flux boundary conditions on the
domain's endpoints. Then, we show numerically that the scheme achieves its full
second-order accuracy in space and time. We also highlight through numerical
simulations how the proposed scheme accurately respects the mass
conservation/balance constraint.Comment: 36 pages, 9 figures, Springer book class; v2 includes improvements
and corrections; to appear as a contribution in "Applied Wave Mathematics II
Perpetrators, victims, bystanders and up standers: cyber bullying in a special school context.
This study offers a multi-dimensional analysis of ‘real world’ cyberbullying between members of a special school community. The purpose of this article is to analyse the social and educational contexts within which interactions of this nature are embedded.The interview both illuminated a number of themes pertinent to the current literature and extended those related to the call for further analysis of the contextual determinants of cyberbullying.The influence of the conditions experienced by the children involved (Attention Deficit Hyperactivity Disorder (ADHD) and Autistic Spectrum Condition (ASC)) is discussed and demonstrated. This use of natural observation provides a current and ‘real world’ illustration of teacher perceptions of the complex behaviours and interactions occurring in cyberspace, which hold potential for grave consequences. A hopeful tone is maintained as the potential for selfless upstander behaviour and resolution via the involvement of supportive and knowledgeable pastoral staff is realised in the article’s conclusion.<br/
On-line detection and quantification of trace impurities in vaporisable samples by direct liquid introduction process mass spectrometry
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