133 research outputs found
The potential of biological soil disinfestation to manage Fusarium foot and root rot in Asparagus
In a field experiment on an abandoned asparagus field we studied the effect of Biological Soil Disinfestation (BSD) on survival of buried inoculum samples of three test pathogens (Fusarium redolens f.sp. asparagi (FRA), Rhizoctonia tuliparum (RT) and Verticillium dahliae (VD)) and on the Fusarium infestation level. The BSD treatments involved incorporation of grass into moist soil and covering the soil with airtight plastic. The amount of grass incorporated was varied (42, 62 or 102 tons of grass/ha) as well as the depth of incorporation (40 or 80 cm). It was found that BSD greatly reduced all three pathogens in buried soil samples and that incorporation of 62 or 102 tons of grass per ha to 80 cm soil depth resulted in a significant decrease in soil infestation in the upper 40 cm; in the deeper layer the decrease was lower. Asparagus plants grown from seed in the field for one year showed a strong decrease in Fusarium root rot severity with all BSD treatments. The results clearly show the potential of BSD to decrease soil infestation levels of Fusarium pathogens and to contribute to an enhanced life span of replanted asparagus crop
Bestrijding Bamboemijt : Een onderzoek naar de chemische en biologische bestrijdingsmogelijkheden van de bamboemijt
De bamboemijten Stigmaeopsis celarius en Stigmaeopsis nanjingensis zorgden, bij de start van dit project, sinds ongeveer 5 jaar in Nederland voor steeds grotere problemen in de bamboeteelt. De schade veroorzaakt door deze bamboemijten neemt dusdanige vormen aan dat kwekers zich zorgen maken over het imago van de bamboeplant als een ‘gezonde’, probleemloze tuinplant. Deze mijtensoorten maken zeer dichte spinsels aan de onderkant van de bladeren. Bij een aantasting neemt de sierwaarde van de planten af. Bij een ernstige aantasting worden de planten onverkoopbaar
High use of SABAs is associated with higher exacerbation rate in Dutch patients with asthma
Funding This study is funded by General Practitioners Research Institute and AstraZeneca Netherlands. The REALISE survey was funded by Mundipharma International Limited (Cambridge, UK). Acknowledgements We would like to thank the core study team, Thys van der Molen, Monica Fletcher, and David Price, the initial researchers of the REALISE study, for their advice on this study. We would like to thank Mundipharma Pharmaceuticals the Netherlands, for providing the data for this study.Peer reviewedPublisher PD
Testing factorization in B -> D(*)X decays
In QCD the amplitude for B0 -> D(*)+pi- factorizes in the large Nc limit or
in the large energy limit Q >> Lambda_QCD where Q = {m_b, m_c, m_b-m_c}. Data
also suggests factorization in exclusive processes B-> D* pi+ pi- pi- pi0 and
B-> D* omega pi-, however by themselves neither large Nc nor large Q can
account for this. Noting that the condition for large energy release in B0-> D+
pi- is enforced by the SV limit, m_b, m_c >> m_b-m_c >> Lambda, we propose that
the combined large Nc and SV limits justify factorization in B -> D(*) X. This
combined limit is tested with the inclusive decay spectrum measured by CLEO. We
also give exact large Nc relations among isospin amplitudes for B -> D(*)X and
B -> D(*) D-bar(*)X, which can be used to test factorization through exclusive
or inclusive measurements. Predictions for the modes B-> D(*) pi pi, B-> D(*)K
K-bar and B-> D(*) D-bar(*) K are discussed using available data.Comment: 15 pages, 3 included .eps figures, minor change
Supersymmetric contributions to B -> D K and the determination of angle \gamma
We analyze supersymmetric contributions to B^- -> D^0 K^- and B^- ->\bar{D}^0
K^- processes. We investigate the possibility that supersymmetric CP violating
phases can affect our determination for the angle \gamma in the unitary
triangle of Cabibbo-Kobayashi-Maskaw mixing matrix. We calculate the gluino and
chargino contributions to b--> u(\bar{c}s) and b-->c(\bar{u}s) transitions in a
model independent way by using the mass insertion approximation method. We also
revise the D^0 - \bar{D}^0 mixing constraints on the mass insertions between
the first and second generations of the up sector. We emphasize that in case of
negligible D^0 -\bar{D}^0 mixing, one should consider simultaneous
contributions from more than one mass insertion in order to be able to obtain
the CP asymmetries of these processes within their 1\sigma experimental range.
However, with a large D^0-\bar{D}^0 mixing, one finds a significant deviation
between the two asymmetries and it becomes natural to have them of order the
central values of their experimental measurements.Comment: 20 page
The transient complex of cytochrome c and cytochrome c peroxidase: insights into the encounter complex from multifrequency EPR and NMR spectroscopy
Biological and Soft Matter Physic
The Meson Lifetime
We investigate the total inclusive decay rate of the (ground state)
meson within the framework of an operator product expansion in inverse powers
of the heavy quark masses and subsequent matching onto nonrelativistic QCD. The
expansion is organized as a series in the strong coupling and in powers of the
heavy quark velocities in the , reflecting the nonrelativistic nature of a
heavy-heavy bound state. In this aspect the character of the expansion differs
from the more familiar case of heavy-light mesons. The framework incorporates
systematically corrections to the leading - and -quark decays due to
binding effects, as well as contributions from weak annihilation and Pauli
interference. Based on this approach we find for the meson lifetime
ps, the dominant mechanism being the decay of the
charm constituent.Comment: 18 pages, revtex, 2 figures as uudecoded fil
Protein dynamics influence the enzymatic activity of phospholipase a/acyltransferases 3 and 4
Phospholipase A/acyltransferase 3 (PLAAT3) and PLAAT4 are enzymes involved in the synthesis of bioactive lipids. Despite sequential and structural similarities, the two enzymes differ in activity and specificity. The relation between the activity and dynamics of the N-terminal domains of PLAAT3 and PLAAT4 was studied. PLAAT3 has a much higher melting temperature and exhibits less nanosecond and millisecond dynamics in the active site, in particular in loop L2(B6), as shown by NMR spectroscopy and molecular dynamics calculations. Swapping the L2(B6) loops between the two PLAAT enzymes results in strongly increased phospholipase activity in PLAAT3 but no reduction in PLAAT4 activity, indicating that this loop contributes to the low activity of PLAAT3. The results show that, despite structural similarity, protein dynamics differ substantially between the PLAAT variants, which can help to explain the activity and specificity differences.Macromolecular BiochemistryMolecular Physiolog
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