284 research outputs found
Complementarity effects through dietary mixing enhance the performance of a generalist insect herbivore
The ontogenetic niche concept predicts that resource use depends on an organism’s developmental stage. This concept has been investigated primarily in animals that show differing resource use strategies as juveniles and as adults, such as amphibians. We studied resource use and performance in the grasshopper Chorthippus parallelus (Orthoptera, Acrididae) provided with food plant mixtures of either one, three or eight plant species throughout their development. C. parallelus survival and fecundity was highest in the food plant mixture with eight plant species and lowest in the treatments where only one single plant species was offered as food. C. parallelus’ consumption throughout its ontogeny depended on sex, and feeding on different plant species was dependent on a grasshopper’s developmental stage. To depict grasshopper foraging in food plant mixtures compared to foraging on single plant species, we introduce the term “relative forage total” (RFT) based on an approach used in biodiversity research by Loreau and Hector (Nature 413:548–274, 2001). RFT of grasshoppers in food plant mixtures was always higher than what would have been expected from foraging in monocultures. The increase in food consumption was due to an overall increase in feeding on plant species in mixtures compared to consumption of the same species offered as a single diet. Thus we argue that grasshopper foraging exhibits complementarity effects. Our results reinforce the necessity to consider development-related changes in insect herbivore feeding. Thorough information on the feeding ontogeny of insect herbivores could not only elucidate their nutritional ecology but also help to shed light on their functional role in plant communities
Associations between MTHFR 1793G>A and plasma total homocysteine, folate, and vitamin B12 in kidney transplant recipients
Associations between MTHFR 1793G>A and plasma total homocysteine, folate, and vitamin B12 in kidney transplant recipients.BackgroundCurrently, no evidence is available on the putative associations between a novel single nucleotide polymorphism of the 5,10-methylenetetrahydrofolate reductase gene MTHFR 1793G>A and plasma levels of vitamin B12, folate, or total homocysteine (tHcy).MethodsIn a cross-sectional study of 730 kidney allograft recipients, patients were categorized by MTHFR 1793G>A genotype. In univariate and multivariate linear regression models that allowed the outcome variables vitamin B12, folate, and tHcy plasma levels to follow a gamma distribution, we tested for possible associations of allelic variants of MTHFR 1793G>A and these three dependent variables. As hypothesized in previous work, we specifically evaluated possible effect modification between the MTHFR 1793G>A and 1298A>C mutations on these outcomes.ResultsThe allele frequency for MTHFR 1793G>A was 0.052. Heterozygosity (N = 72) or homozygosity (N = 2) for MTHFR 1793G>A was not independently associated with plasma levels of vitamin B12 (P = 0.33) or tHcy (P = 0.70), but a borderline association with higher folate concentrations was detected (Δfolate = 1.91 nmol/L) (95% CI -0.03 to 3.86 nmol/L) (P = 0.05). Further, we found strong and significant positive interactions between the MTHFR 1793G>A and 1298A>C mutations on vitamin B12 concentrations.ConclusionHigher folate concentrations in kidney transplant recipients with MTHFR 1793GA or 1793AA and markedly higher concentrations of vitamin B12 in patients with combined MTHFR 1793G>A and 1298A>C mutations may contribute to the survival advantage that has been postulated for such patients showing these genotypes
Heme oxygenase-1 genotype and restenosis after balloon angioplasty: a novel vascular protective factor
AbstractObjectivesWe investigated the association of the heme oxygenase-1 (HO-1) promoter genotype with the inflammatory response and restenosis after balloon angioplasty.BackgroundHeme oxygenase-1, which is induced by balloon angioplasty, can inhibit neointima formation and vascular remodeling. A dinucleotide repeat in the HO-1 gene promoter shows a length polymorphism that modulates HO-1 gene transcription. Short (<25 guanosine thymidine [GT]) repeats are associated with a 10-fold greater up-regulation of HO-1 than are longer repeats.MethodsWe studied 381 consecutive patients who underwent femoropopliteal balloon angioplasty (n = 210) and comparison groups with femoropopliteal stenting (n = 68) and lower limb angiography (n = 103). C-reactive protein (CRP) was measured at baseline, 24, and 48 h. We evaluated patency at six months by duplex sonography and assessed the association of the length of GT repeats in the HO-1 gene promoter with postintervention CRP and restenosis.ResultsRestenosis within six months was found in 74 patients (35%) after balloon angioplasty and in 21 patients (31%) after stenting. After balloon angioplasty, carriers of the short length (<25 GT) dinucleotide repeats had a lower postintervention CRP at 24 h (p = 0.009) and 48 h (p < 0.001) and a reduced risk for restenosis (adjusted relative risk 0.43, 95% confidence interval: 0.24 to 0.71, p < 0.001) compared with patients with longer alleles. After stenting or angiography, we found no association between the HO-1 genotype with CRP or restenosis.ConclusionsThe HO-1 promoter genotype that controls the degree of HO-1 up-regulation in response to stress stimuli is associated with the postintervention inflammatory response and the restenosis risk after balloon angioplasty
Electron Cloud: Observations with LHC-Type Beams in the SPS
In August 1999, strong pressure increases were observed in the SPS in the presence of the new LHC-type beams. This paper reports on observations of the electron cloud phenomenon and the related pressure increase as a function of parameters such as the number of protons per bunch, the number of bunches per batch, the shape of the vacuum chamber and the electron current collected on pick-ups. Results of the observed clean-up, "beam scrubbing" will be presented as well as the consequences of the e-cloud phenomenon on the SPS operation with the LHC nominal beam intensity
Sektoralisierung als Planungsherausforderung im inklusiven Gemeinwesen
2. Hrsg.: Martin F. Reichstein
Förderung durch: Forschungsinstitut für gesellschaftliche Weiterentwicklung (FGW)Seit September 2016 führt das Zentrum für Planung und Evaluation
Sozialer Dienste (ZPE) der Universität Siegen das Forschungsprojekt
„Koordinationspotenziale kommunaler Teilhabepolitik in der Pflege,
Behindertenhilfe und Sozialpsychiatrie (KoKoP)“ durch. Das Projekt wird
im Rahmen des Programms „Vorbeugende Sozialpolitik“ des nordrheinwestfä-
lischen Forschungsinstituts für Gesellschaftliche Weiterentwicklung
(FGW) finanziell gefördert.
Ziel des Projektes ist es, anhand empirischer Untersuchungen Erkenntnisse
darüber zu gewinnen, welche Möglichkeiten für Kommunen bestehen,
durch Planung und Koordination die Wirkungen von Teilhabeleistungen in
den Leistungsbereichen der Pflege, Behindertenhilfe und Sozialpsychiatrie
zu optimieren. Zudem soll der Frage nachgegangen werden, wie
professionelle Hilfen stärker mit informellen Ressourcen im Vor- und
Umfeld des Leistungsgeschehens verknüpft werden können. Mögliche
Problemquellen werden u.a. in einer ausgeprägten Sektoralisierung des
Leistungsgeschehens, mangelnder Kooperation sowie in einer geringen
Sozialraumorientierung vermutet.
Im Rahmen eines eintägigen Expertenworkshops am 14. November
2017 wurden zum einen Zwischenergebnisse bisheriger Untersuchungen
vorgestellt und diskutiert. Zum anderen wurden in drei Arbeitsgruppen
zentrale Fragestellungen des Projekts erörtert. Der vorliegende Band ist
eine Zusammenschau von Beiträgen einzelner Teilnehmer*innen dieses
Workshops
Electron Cloud Effects in the CERN SPS and LHC
Electron cloud effects have been recently observed in the CERN SPS in the presence of LHC type proton beams with 25 ns bunch spacing. Above a threshold intensity of about 4 X 10^12 protons in 81 consecutive bunches, corresponding to half of the nomina
Non-target screening with high-resolution mass spectrometry: critical review using a collaborative trial on water analysis
In this article, a dataset from a collaborative nontarget
screening trial organised by the NORMAN Association
is used to review the state-of-the-art and discuss future perspectives
of non-target screening using high-resolution mass
spectrometry in water analysis. A total of 18 institutes from
12 European countries analysed an extract of the same water
sample collected from the River Danube with either one or both
of liquid and gas chromatography coupled with mass spectrometry detection. This article focuses mainly on the
use of high resolution screening techniques with target, suspect,
and non-target workflows to identify substances in environmental
samples. Specific examples are given to emphasise major
challenges including isobaric and co-eluting substances, dependence
on target and suspect lists, formula assignment, the
use of retention information, and the confidence of identification.
Approaches and methods applicable to unit resolution data
are also discussed. Although most substances were identified
using high resolution data with target and suspect-screening
approaches, some participants proposed tentative non-target
identifications. This comprehensive dataset revealed that nontarget
analytical techniques are already substantially
harmonised between the participants, but the data processing
remains time-consuming. Although the objective of a Bfullyautomated
identification workflow^ remains elusive in the
short term, important steps in this direction have been taken,
exemplified by the growing popularity of suspect screening
approaches. Major recommendations to improve non-target
screening include better integration and connection of desired
features into software packages, the exchange of target and
suspect lists, and the contribution of more spectra from standard
substances into (openly accessible) databases.This work was supported in part by the SOLUTIONS project, which received
funding from the European Union’s Seventh Framework Programme for
research, technological development and demonstration under Grant
Agreement No. 603437
The rotation-coupled sliding of EcoRV
It has been proposed that certain type II restriction enzymes (REs), such as EcoRV, track the helical pitch of DNA as they diffuse along DNA, a so-called rotation-coupled sliding. As of yet, there is no direct experimental observation of this phenomenon, but mounting indirect evidence gained from single-molecule imaging of RE–DNA complexes support the hypothesis. We address this issue by conjugating fluorescent labels of varying size (organic dyes, proteins and quantum dots) to EcoRV, and by fusing it to the engineered Rop protein scRM6. Single-molecule imaging of these modified EcoRVs sliding along DNA provides us with their linear diffusion constant (D1), revealing a significant size dependency. To account for the dependence of D1 on the size of the EcoRV label, we have developed four theoretical models describing different types of motion along DNA and find that our experimental results are best described by rotation-coupled sliding of the protein. The similarity of EcoRV to other type II REs and DNA binding proteins suggests that this type of motion could be widely preserved in other biological contexts
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