341 research outputs found
Schema Bodemplagen als hulpmiddel : Na aaltjesschema nu ook overzicht voor andere bodemplagen in ontwikkeling
Bij welke gewassen moet je als teler op je hoede zijn voor bodemplagen? Welke gewassen zijn het beste te telen als je een bepaald plaaginsect verwacht? Het Schema Bodemplagen is een eenvoudig hulpmiddel
Meereizende insecten duurzamer bestreden
Insecten die meereizen met internationaal verhandeld plantaardig materiaal kunnen de economie flink schaden. Wageningen UR ontwikkelde samen met de sector een milieuvriendelijke bestrijding van de beestjes, die hard nodig is in de handel
Begeleidende rapportage Schema Bodemplagen
De bodem is een reservoir van insecten, waarvan een deel verantwoordelijk is voor economische schade in akkerbouw- en vollegrondsgroentegewassen. Bij de meeste zogenaamde bodeminsecten leeft alleen het volwassen stadium bovengronds; andere stadia leven voornamelijk in de bodem. Daarnaast zijn er veel plaaginsecten die de bodem gebruiken als schuilplaats om een ongunstige periode van het jaar (zoals de winter) door te brengen. Daardoor functioneert de bodem voor veel bodemplagen als een brug van het ene teeltseizoen naar het andere. Doordat de plagen zich kunnen verbergen in de bodem of in het ondergrondse plantenweefsel zijn ze in die levensfase moeilijk te bestrijden. Inzicht in biologische en ecologische aspecten van deze insectenplagen is noodzakelijk om ze doelgericht te beheersen of te bestrijden. Een overzichtelijk bodemplagenschema biedt een degelijke basis voor een milieuvriendelijke en duurzame aanpak van bodemgerelateerde plagen
Why humans are attractive to malaria mosquitoes
Malaria mosquitoes use host odours to find their blood sources, but little is known about the semiochemicals that mediate this behaviour. A combined study is undertaken to identify the volatile human-specific compounds that are used in the host-seeking behaviour of the females of Anopheles gambia
Schwinger boson theory of anisotropic ferromagnetic ultrathin films
Ferromagnetic thin films with magnetic single-ion anisotropies are studied
within the framework of Schwinger bosonization of a quantum Heisenberg model.
Two alternative bosonizations are discussed. We show that qualitatively correct
results are obtained even at the mean-field level of the theory, similar to
Schwinger boson results for other magnetic systems. In particular, the
Mermin-Wagner theorem is satisfied: a spontaneous magnetization at finite
temperatures is not found if the ground state of the anisotropic system
exhibits a continuous degeneracy. We calculate the magnetization and effective
anisotropies as functions of exchange interaction, magnetic anisotropies,
external magnetic field, and temperature for arbitrary values of the spin
quantum number. Magnetic reorientation transitions and effective anisotropies
are discussed. The results obtained by Schwinger boson mean-field theory are
compared with the many-body Green's function technique.Comment: 14 pages, including 7 EPS figures, minor changes, final version as
publishe
Recalibration of the limiting antigen avidity EIA to determine mean duration of recent infection in divergent HIV-1 subtypes.
ArticleBackground: Mean duration of recent infection (MDRI) and misclassification of long-term HIV-1 infections, as proportion false recent (PFR), are critical parameters for laboratory-based assays for estimating HIV-1 incidence. Recent review of the data by us and others indicated that MDRI of LAg-Avidity EIA estimated previously required recalibration. We present here results of recalibration efforts using >250 seroconversion panels and multiple statistical methods to ensure accuracy and consensus. Methods: A total of 2737 longitudinal specimens collected from 259 seroconverting individuals infected with diverse HIV-1 subtypes were tested with the LAg-Avidity EIA as previously described. Data were analyzed for determination of MDRI at ODn cutoffs of 1.0 to 2.0 using 7 statistical approaches and sub-analyzed by HIV-1 subtypes. In addition, 3740 specimens from individuals with infection >1 year, including 488 from patients with AIDS, were tested for PFR at varying cutoffs. Results: Using different statistical methods,MDRI values ranged from 88-94 days at cutoff ODn = 1.0 to 177-183 days at ODn = 2.0. The MDRI values were similar by different methods suggesting coherence of different approaches. Testing formisclassification among long-terminfections indicated that overall PFRs were 0.6%to 2.5%at increasing cutoffs of 1.0 to 2.0, respectively. Balancing the need for a longer MDRI and smaller PFR (<2.0%) suggests that a cutoff ODn = 1.5, corresponding to an MDRI of 130 days should be used for cross-sectional application. The MDRI varied among subtypes from 109 days (subtype A&D) to 152 days (subtype C). Conclusions: Based on the new data and revised analysis, we recommend an ODn cutoff = 1.5 to classify recent and long-term infections, corresponding to an MDRI of 130 days (118-142). Determination of revised parameters for estimation of HIV-1 incidence should facilitate application of the LAg-Avidity EIA for worldwide use.This research has been supported by the President’s Emergency Plan for AIDS Relief
(PEPFAR) through the Centers for Disease Control and Prevention (CDC)
Measurements of the observed cross sections for exclusive light hadrons containing at , 3.650 and 3.6648 GeV
By analyzing the data sets of 17.3, 6.5 and 1.0 pb taken,
respectively, at , 3.650 and 3.6648 GeV with the BES-II
detector at the BEPC collider, we measure the observed cross sections for
, , ,
and at the three energy
points. Based on these cross sections we set the upper limits on the observed
cross sections and the branching fractions for decay into these
final states at 90% C.L..Comment: 7 pages, 2 figure
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