Duurzaam bodembeheer maïs : projectresultaten uit 2013

Hoe kunnen veetelers met minder input meer resultaten halen bij snijmaïsteelt? Wageningen UR en het Louis Bolk Instituut onderzoeken van 2012 tot 2014 in opdracht van het ministerie van EZ duurzame en praktisch haalbare verbeteringen en vernieuwingen. Teeltsystemen die zorgen voor een gezonde bodem worden daarbij gezien als sleutel tot duurzame teelt. Op drie locaties worden diverse teeltsystemen vergeleken in meerjarige proeven uitgevoerd op zand- en kleigrond. Daarbij wordt onder andere gekeken naar opbrengst, onkruiddruk, bodemstructuur, aanwezigheid van regenwormen, indringingsweerstand, waterinfiltratie, stikstofdynamiek en economische aspecten. De resultaten uit het tweede projectjaar (2013) worden in deze rapportage beschreven. Onderstaande paragrafen geven eerst per proeflocatie een korte samenvatting van de bevindingen en de afsluitende paragraaf geeft tot slot de overkoepelende eindconclusies van 2013 en aanbevelingen voor 2014

Schwinger-Dyson approach to non-equilibrium classical field theory

In this paper we discuss a Schwinger-Dyson [SD] approach for determining the time evolution of the unequal time correlation functions of a non-equilibrium classical field theory, where the classical system is described by an initial density matrix at time $t=0$. We focus on $\lambda \phi^4$ field theory in 1+1 space time dimensions where we can perform exact numerical simulations by sampling an ensemble of initial conditions specified by the initial density matrix. We discuss two approaches. The first, the bare vertex approximation [BVA], is based on ignoring vertex corrections to the SD equations in the auxiliary field formalism relevant for 1/N expansions. The second approximation is a related approximation made to the SD equations of the original formulation in terms of $\phi$ alone. We compare these SD approximations as well as a Hartree approximation with exact numerical simulations. We find that both approximations based on the SD equations yield good agreement with exact numerical simulations and cure the late time oscillation problem of the Hartree approximation. We also discuss the relationship between the quantum and classical SD equations.Comment: 36 pages, 5 figure

Duurzaam bodembeheer maïs

Hoe kunnen veetelers met minder input meer resultaten halen bij snijmaïsteelt? Dat is de centrale vraag van het project “Duurzaam bodembeheer maïs”. De maïsteelt kan echter nadelige effecten hebben voor de bodem door gewasbeschermingsmiddelen en het uit- en afspoelen van nutriënten. Wageningen UR en het Louis Bolk Instituut onderzoeken van 2012 tot 2014 in opdracht van het ministerie van EZ duurzame en praktisch haalbare verbeteringen en vernieuwingen. Teeltsystemen die zorgen voor een gezonde bodem worden daarbij gezien als sleutel tot duurzame teelt. Op drie locaties worden diverse teeltsystemen vergeleken in meerjarige proeven uitgevoerd op zand- en kleigrond. Daarbij wordt onder andere gekeken naar opbrengst, onkruiddruk, bodemstructuur, aanwezigheid van regenwormen, indringingsweerstand, waterinfiltratie, stikstofdynamiek en economische aspecten. De resultaten uit het eerste projectjaar (2012) worden in deze rapportage beschreven

Transport coefficients and resonances for a meson gas in Chiral Perturbation Theory

We present recent results on a systematic method to calculate transport coefficients for a meson gas (in particular, we analyze a pion gas) at low temperatures in the context of Chiral Perturbation Theory (ChPT). Our method is based on the study of Feynman diagrams taking into account collisions in the plasma by means of the non-zero particle width. This implies a modification of the standard ChPT power counting scheme. We discuss the importance of unitarity, which allows for an accurate high energy description of scattering amplitudes, generating dynamically the $\rho (770)$ and $f_0(600)$ mesons. Our results are compatible with analyses of kinetic theory, both in the non-relativistic very low-$T$ regime and near the transition. We show the behavior with temperature of the electrical and thermal conductivities as well as of the shear and bulk viscosities. We obtain that bulk viscosity is negligible against shear viscosity, except near the chiral phase transition where the conformal anomaly might induce larger bulk effects. Different asymptotic limits for transport coefficients, large-$N_c$ scaling and some applications to heavy-ion collisions are studied.Comment: Invited talk given at the international workshop Hot Quarks 2008, Estes Park, Colorado, USA, August 18-23 2008. Accepted as a regular article in Eur.Phys.J.C. 18 pages EPJC style, 23 figure

Design-for-testability of PLA's using statistical cooling

A method for designing easily testable PLA's with low overhead is presented. The method is based on a reduction of product lines and the addition of a small number of inputs. The required additional hardware is calculated using a statistical cooling algorithm. The presented design-for-testability method guarantees a 100 percent fault coverage with respect to multiple stuck-at faults and multiple missing/extra crosspoint faults

Classroom bullying norms and peer status: Effects on victim-oriented and bully-oriented defending

Defending a victimized peer is a socially risky behavior that may require high peer status and may depend on how popular or disliked bullies are in the classroom (i.e., within-classroom correlations between bullying and status). Past research has investigated defending as a unidimensional construct, though it can involve confronting the bully (bully-oriented defending) or supporting the victim (victim-oriented defending). This study used multilevel modeling to examine the effects of individual peer status, gender, and bullying as well as two indicators of classroom norms—the bullying-popularity norm and the bullying-rejection norm—on both types of defending. Our sample included 1,460 Dutch adolescents (50% girls; M age 11 years) from 59 classrooms in 50 schools. Likability and popularity were positively associated with both types of defending. Being female and lower in bullying was associated with victim-oriented defending, whereas being male and higher in bullying was associated with bully-oriented defending. In classrooms where bullies were more rejected, both types of defending were more prevalent, and the positive associations of likability and popularity with victim-oriented defending were stronger. The positive effect of the bullying-rejection norm on victim-oriented defending was stronger for girls. Moreover, the effect of popularity on bully-oriented defending was stronger in classrooms where bullies were less popular

Remarkable differences between three evidence-based guidelines on management of obstructive sleep apnea-hypopnea syndrome

Item does not contain fulltextOBJECTIVES/HYPOTHESIS: The aim of this study was to compare available guidelines for the diagnosis and treatment of patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) regarding their content, conclusions on the available evidence, and recommendations. STUDY DESIGN: Literature review/systematic review. METHODS: We retrieved guidelines from Embase, PubMed, Web of Science, and Web sites of several health care improvement centers and with a Google Scholar search. We appraised the quality of selected guidelines according to the Appraisal of Guidelines for Research and Evaluation instrument. For similar clinical questions we compared the conclusions, the attached levels of evidence, and the references used. If differences were found, we checked search strategies, appraisal criteria, and publication date as possible sources for these differences. RESULTS: We selected the guidelines on diagnosis and treatment of OSAHS of the Scottish Scottish Intercollegiate Guidelines Network, the Dutch Institute for Healthcare Improvement, and the Institute for Clinical Systems Improvement in the United States for this comparison. For similar clinical questions these three guidelines showed conflicting conclusions (11%-18%), differences in attached levels of evidence (32%-62%), and remarkable discrepancies in cited studies. A plausible reason for these differences is the citation preference for articles from members of the guidelines workgroup and from their own country. Despite different publication dates, more recent guidelines fail to cite earlier published guidelines. CONCLUSIONS: Despite the generally accepted approach regarding the development of evidence-based guidelines, remarkable differences exist between guidelines from different countries on the same clinical subject

Response to "Routine testing of Borrelia serology in sudden sensorineural hearing loss" from James E. Saunders

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