Suitability of spiders and rove beetles as indicators for assessment of effects of cultivation-rearrangement from conventional to ecological farming

Im Gebiet des Ökohofes Seeben ließen sich im Verlauf von 4 Jahren arten- und individuenreiche Webspinnen- und Kurzflüglerzönosen registrieren (LÜBKE-AL HUSSEIN & AL HUSSEIN 1999; AL HUSSEIN 2002). Zu Beginn der Untersuchungen wurde die Arbeitshypothese formuliert: Die Fauna eines Agrar-Ökosystems wird durch die Intensität der Landbewirtschaftung sowie durch landschaftsräumliche Gliederung des Gebietes entscheidend geprägt. Die Umstellung eines bislang konventionell wirtschaftenden Betriebes auf ökologischen Landbau und die damit einhergehende Strukturierung ausgeräumter Flächen durch Feldraine, Hecken oder auch nur den streifenweisen Anbau mehrerer Kulturen auf einem Großschlag bewirkt eine Erhöhung der Faunendiversität. Die wachsende Diversität der Tierwelt begünstigt selbstregulative Prozesse der Agrozönose und wirkt dadurch stabilisierend auf das Ökosystem. Das Forschungsvorhaben kann als ein "Langzeit-Experiment" aufgefaßt werden, wobei die Anfangsbedingungen vor der Betriebsumstellung als referenzzustand dienen (HÜLSBERGEN & DIEPENBROCK, 2000). Webspinnen und Kurzflügelkäfer zählen zu den arten- und individuenreichsten Tiergruppen der Agrarlandschaft. Sie leben fast ausnahmslos räuberisch und spielen als Regulatoren von Schadinsektenpopulationen besonders im ökologischen Landbau eine bedeutende Rolle. Aufgrund ihrer Sensibilität gegenüber Umwelteinflüssen eignen sie sich als Indikatoren. Insbesondere Webspinnen werden für derartige Untersuchungen herangezogen. Einige können sogar als Zeigerarten angesehen werden. Bei vorliegenden Erhebungen galt es u. a. zu prüfen, inwieweit die weniger untersuchten Kurzflügler im Vergleich zu den Webspinnen zu derartigen Fragestellungen herangezogen werden können.From 1994 to 1997 investigations have been carried out on fields of the “Ökohof Seeben” in the North of Halle (Saale) refering to long-term effects of ecological farming on spiders and rove beetles. Two fields were selected in the northern part of the eco-farm representing different types of landscape. The question was whether ecological farming results in an increasing biodiversity over longer periods. For sampling of these arthropods pitfall traps were used. As a whole the communities of spiders and rove beetles were rich in species and individuals. The rearrangement from conventional to ecological agriculture did not provide the expected increase of biodiversity, but it showed positive tendencies such as the homogeneity of dominance structures and an increase of the number of species larger in size. The investigated parameters were influenced through different factors, e.g. the spiders more by field size and rove beetles especially by crop rotation. The occurrence of rove beetles depends on their high substrate specification and the existence of ecological niches, too. Such as these investigations should be carried out as long-term-experiments, because shorter experiments may lead to misinterpretations

Spontaneous spiking in an autaptic Hodgkin-Huxley set up

The effect of intrinsic channel noise is investigated for the dynamic response of a neuronal cell with a delayed feedback loop. The loop is based on the so-called autapse phenomenon in which dendrites establish not only connections to neighboring cells but as well to its own axon. The biophysical modeling is achieved in terms of a stochastic Hodgkin-Huxley model containing such a built in delayed feedback. The fluctuations stem from intrinsic channel noise, being caused by the stochastic nature of the gating dynamics of ion channels. The influence of the delayed stimulus is systematically analyzed with respect to the coupling parameter and the delay time in terms of the interspike interval histograms and the average interspike interval. The delayed feedback manifests itself in the occurrence of bursting and a rich multimodal interspike interval distribution, exhibiting a delay-induced reduction of the spontaneous spiking activity at characteristic frequencies. Moreover, a specific frequency-locking mechanism is detected for the mean interspike interval.Comment: 8 pages, 10 figure

Stability and Hermitian-Einstein metrics for vector bundles on framed manifolds

We adapt the notions of stability of holomorphic vector bundles in the sense of Mumford-Takemoto and Hermitian-Einstein metrics in holomorphic vector bundles for canonically polarized framed manifolds, i.e. compact complex manifolds X together with a smooth divisor D such that K_X \otimes [D] is ample. It turns out that the degree of a torsion-free coherent sheaf on X with respect to the polarization K_X \otimes [D] coincides with the degree with respect to the complete K\"ahler-Einstein metric g_{X \setminus D} on X \setminus D. For stable holomorphic vector bundles, we prove the existence of a Hermitian-Einstein metric with respect to g_{X \setminus D} and also the uniqueness in an adapted sense.Comment: 21 pages, International Journal of Mathematics (to appear

Investigations on the influence of conservation tillage strategies on the composition of the soil mesofauna by using the litter-bag-method

Elemente der Bodenmesofauna gehören gerade in pfluglosen Anbausystemen zu den bedeutendsten Primärzersetzern von Ernterückständen. Für den Rotteprozess, der nicht nur für die Pflanzengesundheit von größter Bedeutung ist, spielen sie damit eine entscheidende Rolle. Während Effekte der Bodenbearbeitung auf die mikrobielle Biomasse in den letzten Jahrzehnten Gegenstand zahlreicher Feldstudien waren, sind entsprechende Erhebungen zur Bodenmesofauna vergleichsweise rar und darüber hin in ihren Aussagen teilweise widersprüchlich. Positive Effekte auf Streuabbau durch reduzierte Intensität der Bodenbearbeitung konnten Heiber & Eisenbeis (1999) nachweisen. Vorliegende Untersuchungen sollten klären, welche Auswirkungen die Bodenbearbeitung auf die vielfältigen Zönosen der Bodenmesofauna eines intensiv ackerbaulich genutzten Lößstandortes hat.The soil mesofauna has an important role for the decomposition of organic materials in non-till cultivation systems. The investigations have been carried out on fields of Lüttewitz (Saxony, Germany). There were investigated 4 cultivation variants, which were still used on each plot more than 10 years: plough; mulch sowing with deep loosening; mulch till with shallow loosening and direct drilling. In each variant 20 litterbags (mesh size: 2 mm; litter weight: 20 g); (exposition period: spring till early summer 2006) were placed under the soil surface. To investigate the possible effects of the litter size on the colonization by the soil mesofauna, two litter variants (Maize chopped straw fine/cereals straw rough) were used. The litterbags were controlled at three times. At first a wet-extraction was carried out to estimate the dense of Enchytraeidae (Oligochaeta). Afterwards a dry extraction of the mesofauna with the Tullgren-method followed to find out the amount of mites (Oribatida and Acaridida) and Collembola, which are important for decomposition of the litter. Among the Oribatida the species Tectocepheus velatus and Oppiella nova reached high densities. The predatory Gamasina were dominated by the families Rhodacaridae, Parasitidae, Ascidae, Veigaiaidae, Macrochelidae and Zerconidae. All times the fine litter in all plots was stronger colonized. In rough litter the part of Gamasina as predators was lower than the decomposer groups. With the declining of the intensity of tillage the colonization of the litter-bags increased. In the variant mulch-till (with shallow loosening) the highest densities of individuals were found. The registered numbers often were higher as in the plots with direct drilling

Puerperal influence of bovine uterine health status on the mRNA expression of pro-inflammatory factors

After parturition, uterine bacterial infections lead to inflammatory processes such as subclinical/clinical endometritis with high prevalence in dairy cows. Endometrial epithelial cells participate in this immune response with the production of pro-inflammatory factors. The objective of the present study was to evaluate the endometrial mRNA expression pattern of pro inflammatory factors during a selected postpartum (pp) period. Dairy cows with three different uterine health conditions on days 24-30 pp (healthy: n = 11, subclinical endometritis: n = 10, clinical endometritis: n = 10) were sampled using the cytobrush technique. Subsequently, each cow was sampled 3 more times in weekly intervals (days 31-37 pp; days 38-44 pp; days 45-51 pp). Samples were subjected to mRNA analysis performed by RT-qPCR. Additionally, an analysis of cultivable bacteria was performed at the early/late stage of the selected puerperal period. mRNA expression of 16 candidate genes was analyzed by using two different approaches. The first approach referred to the initial grouping on days 24-30 pp to reveal long-term effects of the uterine health on the subsequent puerperal period. The second approach considered the current uterine health status at each sampling to elucidate the impact of different points in time. Long-term effects seem to appear for chemokines, prostacyclin synthase and prostaglandin D2 synthase. If related to the current uterine health, the majority of candidate genes were significantly higher expressed in endometritic cows on days 45-51 pp in contrast to earlier stages of the puerperium. Microbiological analysis revealed the significantly higher prevalence of Trueperella pyogenes findings in cows with clinical endometritis on days 24-30 pp, but no correlations were found on days 45-51 pp. In conclusion, a strong immune response to subclinical/clinical endometritis in the late puerperium may be related to the negative impact of these conditions on reproductive performance in dairy cows

Antenna Setup for Future Joint Radar-Communications – Characteristics and Mounting Positions

The development of millimeter wave systems is driven by the strong trend toward new communications generations and especially by the emerging joint radar and communications design approach. Safety-critical applications like platooning or intersection assistance will significantly benefit from the combination of sensing and communications. While radar performs a channel measurement and thus, needs a wide field of view (especially in city/intersection scenarios), communications aims to minimize the interference for other not addressed receivers (e. g. in a platoon) by a focused antenna design. The proposed work extends the analysis of the influence of various antenna positioning for a typical automotive scene by taking also different characteristics (antenna gain, half power beamwidth, and sidelobe level) into account. Hereby, it is mandatory to investigate the communications and sensing performance simultaneously. The positions at the front bumper – typical for radar sensors – and especially at the left mirror convinced regarding the vehicular communications as well as the sensing behaviour. Applying focused antennas is promising, however, has also limits if the signals are not received out of the main beam but out of the sidelobes, resulting in a critical communications performance. Thus, beam steering is recommended to be applied in the future.</p

Comprehensive Flow Cytometric Characterization of Bronchoalveolar Lavage Cells Indicates Comparable Phenotypes Between Asthmatic and Healthy Horses But Functional Lymphocyte Differences

Equine asthma (EA) is a highly relevant disease, estimated to affect up to 20% of all horses, and compares to human asthma. The pathogenesis of EA is most likely immune-mediated, yet incompletely understood. To study the immune response in the affected lower airways, mixed leukocytes were acquired through bronchoalveolar lavage (BAL) and the cell populations were analyzed on a single-cell basis by flow cytometry (FC). Samples of 38 horses grouped as respiratory healthy or affected by mild to moderate (mEA) or severe EA (sEA) according to their history, clinical signs, and BAL cytology were analyzed. Using FC, BAL cells and PBMC were comprehensively characterized by cell surface markers ex vivo. An increased percentage of DH24A+ polymorphonuclear cells, and decreased percentages of CD14+ macrophages were detected in BAL from horses with sEA compared to healthy horses or horses with mEA, while lymphocyte proportions were similar between all groups. Independently of EA, macrophages in BAL were CD14+CD16+, which contrasts the majority of CD14+CD16- classical monocytes in PBMC. Percentages of CD16-expressing BAL macrophages were reduced in BAL from horses with sEA compared to healthy horses. While PBMC lymphocytes predominantly contain CD4+ T cells, B cells and few CD8+ T cells, BAL lymphocytes comprised mainly CD8+ T cells, fewer CD4+ T cells and hardly any B cells. These lymphocyte subsets' distributions were similar between all groups. After PMA/ionomycin stimulation in vitro, lymphocyte activation (CD154 and T helper cell cytokine expression) was analyzed in BAL cells of 26 of the horses and group differences were observed (p=0.01-0.11). Compared to healthy horses' BAL, CD154+ lymphocytes from horses with mEA, and CD4+IL-17A+ lymphocytes from horses with sEA were increased in frequency. Activated CD4+ T helper cells were more frequent in asthmatics' (mEA, sEA) compared to healthy horses' PBMC lymphocytes. In summary, FC analysis of BAL cells identified increased polymorphonuclear cells frequencies in sEA as established, while macrophage percentages were mildly reduced, and lymphocyte populations remained unaffected by EA. Cytokine production differences of BAL lymphocytes from horses with sEA compared to healthy horses' cells point towards a functional difference, namely increased local type 3 responses in sEA

Investigation of the Reduction of Nitric Oxides by CO and H2 on Pt-Mo Catalysts under Oxidizing Conditions

The reduction of NO by CO on Pt has been extensively investigated in the past since it helps to eliminate NO of the exhaust gas of cars. However, the dissociation of NO in this reaction and the deactivation of the NO/CO reaction on Pt-supported catalysts still need to be discussed. In this work, the reduction of NO with CO is examined on a 0.5 % Pt-3.4 % MoO3/alpha-Al2O3 catalyst. The results of a kinetic modeling are presented and a new proposition concerning the mechanism of the observed deactivation is made. To the authors knowledge, this is the first study where the kinetics of the N2O formation on a Pt-catalyst is established

Approximate Hermitian-Yang-Mills structures and semistability for Higgs bundles. II: Higgs sheaves and admissible structures

We study the basic properties of Higgs sheaves over compact K\"ahler manifolds and we establish some results concerning the notion of semistability; in particular, we show that any extension of semistable Higgs sheaves with equal slopes is semistable. Then, we use the flattening theorem to construct a regularization of any torsion-free Higgs sheaf and we show that it is in fact a Higgs bundle. Using this, we prove that any Hermitian metric on a regularization of a torsion-free Higgs sheaf induces an admissible structure on the Higgs sheaf. Finally, using admissible structures we proved some properties of semistable Higgs sheaves.Comment: 18 pages; some typos correcte

How to survive pig farming: Mechanism of SCCmec element deletion and metabolic stress adaptation in livestock-associated MRSA

Previous research on methicillin susceptible Staphylococcus aureus (MSSA) belonging to livestock-associated (LA-) sequence type (ST) 398, isolated from pigs and their local surroundings, indicated that differences between these MSSA and their methicillin resistant predecessors (MRSA) are often limited to the absence of the staphylococcal cassette chromosome mec (SCCmec) and few single nucleotide polymorphisms. So far, our understanding on how LA-MRSA endure the environmental conditions associated with pig-farming as well as the putative impact of this particular environment on the mobilisation of SCCmec elements is limited. Thus, we performed in-depth genomic and transcriptomic analyses using the LA-MRSA ST398 strain IMT38951 and its methicillin susceptible descendant. We identified a mosaic-structured SCCmec region including a putative replicative SCCmecVc which is absent from the MSSA chromosome through homologous recombination. Based on our data, such events occur between short repetitive sequences identified within and adjacent to two distinct alleles of the large cassette recombinase genes C (ccrC). We further evaluated the global transcriptomic response of MRSA ST398 to particular pig-farm associated conditions, i.e., contact with host proteins (porcine serum) and a high ammonia concentration. Differential expression of global regulators involved in stress response control were identified, i.e., ammonia-induced alternative sigma factor B-depending activation of genes for the alkaline shock protein 23, the heat shock response and the accessory gene regulator (agr)-controlled transcription of virulence factors. Exposure to serum transiently induced the transcription of distinct virulence factor encoding genes. Transcription of genes reported for mediating the loss of methicillin resistance, especially ccrC, was not significantly different compared to the unchallenged controls. We concluded that, from an evolutionary perspective, bacteria may save energy by incidentally dismissing a fully replicative SCCmec element in contrast to the induction of ccr genes on a population scale. Since the genomic SCCmec integration site is a hot-spot of recombination, occasional losses of elements of 16 kb size may restore capacities for the uptake of foreign genetic material. Subsequent spread of resistance, on the other hand, might depend on the autonomous replication machinery of the deleted SCCmec elements that probably enhance chances for reintegration of SCCmec into susceptible genomes by mere multiplication