135 research outputs found
On Pure Spinor Superfield Formalism
We show that a certain superfield formalism can be used to find an off-shell
supersymmetric description for some supersymmetric field theories where
conventional superfield formalism does not work. This "new" formalism contains
even auxiliary variables in addition to conventional odd super-coordinates. The
idea of this construction is similar to the pure spinor formalism developed by
N.Berkovits. It is demonstrated that using this formalism it is possible to
prove that the certain Chern-Simons-like (Witten's OSFT-like) theory can be
considered as an off-shell version for some on-shell supersymmetric field
theories. We use the simplest non-trivial model found in [2] to illustrate the
power of this pure spinor superfield formalism. Then we redo all the
calculations for the case of 10-dimensional Super-Yang-Mills theory. The
construction of off-shell description for this theory is more subtle in
comparison with the model of [2] and requires additional Z_2 projection. We
discover experimentally (through a direct explicit calculation) a non-trivial
Z_2 duality at the level of Feynman diagrams. The nature of this duality
requires a better investigation
A manual for large-scale sample collection, preservation, tracking, DNA extraction, and variety identification analysis
Several alternative options have been used for varietal identification. However most of the traditional methods have inherent uncertainty levels and estimates often have wide confidence intervals. In an attempt to circumvent traditional survey-based measurement errors in varietal identification, DNA-based varietal identification has been implemented in the Cassava Monitoring Survey (CMS) of Nigeria — a large adoption study involving 2500 cassava farming households. The DNA fingerprinting technique offers a reliable
method to accurately identify varieties grown by farmers and increases accuracy and credibility in the interpretation of adoption rates and associated economic and policy analyses. Unlike phenotype-based methods, DNA is not affected by environmental conditions or plant growth stage and is more abundant than morphological descriptors. However, undertaking a credible DNA-based varietal identification is not a trivial matter because of the logistical challenges involving sample collection and tracking by a large team of field enumerators. This manual presents the detailed steps required for undertaking reliable DNA-fingerprinting-based identification of cassava varieties. In particular, the manual gives detailed information on the establishment of a sample tracking system, preparation of a readily available and cheap sample collection kit, field sample collection methodology, preparation of samples for DNA isolation, and
development of a pipeline for variety identification analysis. This manual is part of the outputs of the CMS project funded by the CGIAR Research Program on Roots, Tubers and Bananas (RTB), the Bill & Melinda Gates Foundation, and the International Institute of Tropical Agriculture (IITA)
Electronic transport through domain walls in ferromagnetic nanowires: Co-existence of adiabatic and non-adiabatic spin dynamics
We study the effect of a domain wall on the electronic transport in
ferromagnetic quantum wires. Due to the transverse confinement, conduction
channels arise. In the presence of a domain wall, spin up and spin down
electrons in these channels become coupled. For very short domain walls or at
high longitudinal kinetic energy, this coupling is weak, leads to very few spin
flips, and a perturbative treatment is possible. For very long domain wall
structures, the spin follows adiabatically the local magnetization orientation,
suppressing the effect of the domain wall on the total transmission, but
reversing the spin of the electrons. In the intermediate regime, we numerically
investigate the spin-dependent transport behavior for different shapes of the
domain wall. We find that the knowledge of the precise shape of the domain wall
is not crucial for determining the qualitative behavior. For parameters
appropriate for experiments, electrons with low longitudinal energy are
transmitted adiabatically while the electrons at high longitudinal energy are
essentially unaffected by the domain wall. Taking this co-existence of
different regimes into account is important for the understanding of recent
experiments.Comment: 10 pages, 6 figure
Het managen van incidenten in het onderwijs. Praktische governance-lessen op basis van een vergelijkende case analyse
Bij iedere onderwijsorganisatie doen zich incidenten voor. Deze incidenten lopen soms ernstig uit de hand. Er zijn echter ook incidenten die tijdig en effectief worden aangepakt en niet uitgroeien tot echte ongelukken of zelfs misstanden. Aan de hand van zes concrete incidenten binnen het onderwijsdomein is onderzocht hoe dankzij adequaat optreden ongelukken zijn voorkomen en welke mechanismen daarbij een rol spelen
Cassava farmers' preferences for varieties and seed dissemination system in Nigeria: gender and regional perspectives
The Cassava Monitoring Survey (CMS) project was funded by the CGIAR-RTB
Program and the Bill & Melinda Gates Foundation. The main goal was to carry out a
study on cassava adoption and diffusion patterns in Nigeria. This includes explaining
why farmers are adopting certain varieties and describing preference differences across
regions and gender. This specific study and report is part of Component IV of the
broader CMS Project, and it covered gender-differentiated, end-user surveys on varietal
and trait preferences. The objective of this component was to use qualitative methods to
probe deeper into some of the information that was obtained in the quantitative survey
on gender-based trait preferences and seed dissemination pathways
The clustering instability of inertial particles spatial distribution in turbulent flows
A theory of clustering of inertial particles advected by a turbulent velocity
field caused by an instability of their spatial distribution is suggested. The
reason for the clustering instability is a combined effect of the particles
inertia and a finite correlation time of the velocity field. The crucial
parameter for the clustering instability is a size of the particles. The
critical size is estimated for a strong clustering (with a finite fraction of
particles in clusters) associated with the growth of the mean absolute value of
the particles number density and for a weak clustering associated with the
growth of the second and higher moments. A new concept of compressibility of
the turbulent diffusion tensor caused by a finite correlation time of an
incompressible velocity field is introduced. In this model of the velocity
field, the field of Lagrangian trajectories is not divergence-free. A mechanism
of saturation of the clustering instability associated with the particles
collisions in the clusters is suggested. Applications of the analyzed effects
to the dynamics of droplets in the turbulent atmosphere are discussed. An
estimated nonlinear level of the saturation of the droplets number density in
clouds exceeds by the orders of magnitude their mean number density. The
critical size of cloud droplets required for clusters formation is more than
m.Comment: REVTeX 4, 15 pages, 2 figures(included), PRE submitte
Diagnostic yield of a proactive strategy for early detection of cardiovascular disease versus usual care in adults with type 2 diabetes or chronic obstructive pulmonary disease in primary care in the Netherlands (RED-CVD):a multicentre, pragmatic, cluster-randomised, controlled trial
Background: Progressive cardiovascular diseases (eg, heart failure, atrial fibrillation, and coronary artery disease) are often diagnosed late in high-risk individuals with common comorbidities that might mimic or mask symptoms, such as chronic obstructive pulmonary disease (COPD) and type 2 diabetes. We aimed to assess whether a proactive diagnostic strategy consisting of a symptom and risk factor questionnaire and low-cost and accessible tests could increase diagnosis of progressive cardiovascular diseases in patients with COPD or type 2 diabetes in primary care. Methods:In this multicentre, pragmatic, cluster-randomised, controlled trial (RED-CVD), 25 primary care practices in the Netherlands were randomly assigned to usual care or a proactive diagnostic strategy conducted during routine consultations and consisting of a validated symptom questionnaire, followed by physical examination, N-terminal-pro-B-type natriuretic peptide measurement, and electrocardiography. We included adults (≥18 years) with type 2 diabetes, COPD, or both, who participated in a disease management programme. Patients with an established triple diagnosis of heart failure, atrial fibrillation, and coronary artery disease were excluded. In the case of abnormal findings, further work-up or treatment was done at the discretion of the general practitioner. The primary endpoint was the number of newly diagnosed cases of heart failure, atrial fibrillation, and coronary artery disease, adjudicated by an expert clinical outcome committee using international guidelines, at 1-year follow-up, in the intention-to-treat population. Findings: Between Jan 31, 2019, and Oct 7, 2021, we randomly assigned 25 primary care centres: 11 to usual care and 14 to the intervention. We included patients between June 21, 2019, and Jan 31, 2022. Following exclusion of ineligible patients and those who did not give informed consent, 1216 participants were included: 624 (51%) in the intervention group and 592 (49%) in the usual care group. The mean age of participants was 68·4 years (SD 9·4), 482 (40%) participants were female, and 734 (60%) were male. During 1 year of follow-up, 50 (8%) of 624 participants in the intervention group and 18 (3%) of 592 in the control group were newly diagnosed with heart failure, atrial fibrillation, or coronary artery disease (adjusted odds ratio 2·97 [95% CI 1·66–5·33]). This trial is registered with the Netherlands Trial Registry, NTR7360, and was completed on Jan 31, 2023. Interpretation: An easy-to-use, proactive, diagnostic strategy more than doubled the number of new diagnoses of heart failure, atrial fibrillation, and coronary artery disease in patients with type 2 diabetes or COPD in primary care compared with usual care. Although the effect on patient outcomes remains to be studied, our diagnostic strategy might contribute to improved early detection and timely initiation of treatment in individuals with cardiovascular disease. Funding: Dutch Heart Foundation.</p
Behoorlijk Bestuur van Onderwijsinstellingen
Het doel van dit onderzoek luidt:
- Het conceptualiseren van behoorlijk bestuur als een levende en lerende bestuurspraktijk die verder gaat dan alleen maar een set van principes die verwoord zijn in een governance code.
- Het beschrijven van praktijken van duurzaam behoorlijk bestuur op het niveau van gedrag en cultuur in onderwijsinstellingen waar corrigerende mechanismen aantoonbaar hebben gewerkt;
- het analyseren van de condities waaronder deze mechanismen werken; en
- het formuleren van uitgangspunten voor de versterking van het corrigerende vermoge
Cohort profile of BIOMArCS: The BIOMarker study to identify the Acute risk of a Coronary Syndrome-a prospective multicentre biomarker study conducted in the Netherlands
__Purpose:__ Progression of stable coronary artery disease (CAD) towards acute coronary syndrome (ACS) is a dynamic and heterogeneous process with many intertwined constituents, in which a plaque destabilising sequence could lead to ACS within short time frames. Current CAD risk assessment models, however, are not designed to identify increased vulnerability for the occurrence of coronary events within a precise, short time frame at the individual patient level. The BIOMarker study to identify the Acute risk of a Coronary Syndrome (BIOMArCS) was designed to evaluate whether repeated measurements of multiple biomarkers can predict such 'vulnerable periods'.
__Participants:__ BIOMArCS is a multicentre, prospective, observational study of 844 patients presenting with ACS, either with or without ST-elevation and at least one additional cardiovascular risk factor.
__Methods and analysis:__ We hypothesised that patterns of circulating biomarkers that reflect the various pathophysiological components of CAD, such as distorted lipid metabolism, vascular inflammation, endothelial dysfunction, increased thrombogenicity and ischaemia, diverge in the days to weeks before a coronary event. Divergent biomarker patterns, identified by serial biomarker measurements during 1-year follow-up might then indicate 'vulnerable periods' during which patients with CAD are at high short-Term risk of developing an ACS. Venepuncture was performed every fortnight during the first half-year and monthly thereafter. As prespecified, patient enrolment was terminated after the primary end point of cardiovascular death or hospital admission for nonfatal ACS had occurred in 50 patients. A case-cohort design will explore differences in temporal patterns of circulating biomarkers prior to the repeat ACS
High prevalence of non-accidental trauma among deceased children presenting at Level I trauma centers in the Netherlands
PURPOSE: Between 0.1—3% of injured children who present at a hospital emergency department ultimately die as a result of their injuries. These events are typically reported as unnatural causes of death and may result from either accidental or non-accidental trauma (NAT). Examples of the latter include trauma that is inflicted directly or resulting from neglect. Although consultation with a forensic physician is mandatory for all deceased children, the prevalence of fatal inflicted trauma or neglect among children is currently unclear. METHODS: This is a retrospective study that included children (0–18 years) who presented and died at one of the 11 Level I trauma centers in the Netherlands between January 1, 2014, and January 1, 2019. Outcomes were classified based on the conclusions of the Child Abuse and Neglect team or those of forensic pathologists and/or the court in cases referred for legally mandated autopsies. Cases in which conclusions were unavailable and there was no clear accidental cause of death were reviewed by an expert panel. RESULTS: The study included 175 cases of childhood death. Seventeen (9.7%) of these children died due to inflicted trauma (9.7%), 18 (10.3%) due to neglect, and 140 (80%) due to accidents. Preschool children (< 5 years old) were significantly more likely to present with injuries due to inflicted trauma and neglect compared to older children (44% versus 6%, p < 0.001, odds ratio [OR] 5.80, 95% confidence interval [CI] 2.66–12.65). Drowning accounted for 14 of the 18 (78%) pediatric deaths due to neglect, representing 8% of the total cases. Postmortem radiological studies and autopsies were performed on 37 (21%) of all cases of childhood death. CONCLUSION: One of every five pediatric deaths in our nationwide Level I trauma center study was attributed to NAT; 44% of these deaths were the result of trauma experienced by preschool-aged children. A remarkable number of fatal drownings were due to neglect. Postmortem radiological studies and autopsies were performed in only one-fifth of all deceased children. The limited use of postmortem investigations may have resulted in missed cases of NAT, which will result in an overall underestimation of fatal NAT experienced by children. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12024-021-00416-7
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