Temporal modulation transfer functions in the European Starling (Sturnus vulgaris): II. Responses of auditory-nerve fibres

The temporal resolution of cochlear-nerve fibres in the European starling was determined with sinusoidally amplitude-modulated noise stimuli similar to those previously used in a psychoacoustic study in this species (Klump and Okanoya, 1991). Temporal modulation transfer curves (TMTFs) were constructed for cochlear afferents allowing a direct comparison with the starling's behavioural performance. On average, the neuron's detection of modulation was less sensitive than that obtained in the behavioural experiments, although the most sensitive cells approached the values determined psychophysically. The shapes of the neural TMTFs generally resembled low-pass or band-pass filter functions, and the shapes of the averaged neural functions were very similar to those obtained in the behavioural study for two different types of stimuli (gated and continuous carrier). Minimum integration times calculated from the upper cut-off frequency of the neural TMTFs had a median of 0.97 ms with a range of 0.25 to 15.9 ms. The relations between the minimum integration times and the tuning characteristics of the cells (tuning curve bandwidth, Q10 dB-value, high- and low-frequency slopes of the tuning curves) are discussed. Finally, we compare the TMTF data recorded in the starling auditory nerve with data from neurophysiological and behavioural observations on temporal resolution using other experimental paradigms in this and other vertebrate species

Querying the Guarded Fragment

Evaluating a Boolean conjunctive query Q against a guarded first-order theory F is equivalent to checking whether "F and not Q" is unsatisfiable. This problem is relevant to the areas of database theory and description logic. Since Q may not be guarded, well known results about the decidability, complexity, and finite-model property of the guarded fragment do not obviously carry over to conjunctive query answering over guarded theories, and had been left open in general. By investigating finite guarded bisimilar covers of hypergraphs and relational structures, and by substantially generalising Rosati's finite chase, we prove for guarded theories F and (unions of) conjunctive queries Q that (i) Q is true in each model of F iff Q is true in each finite model of F and (ii) determining whether F implies Q is 2EXPTIME-complete. We further show the following results: (iii) the existence of polynomial-size conformal covers of arbitrary hypergraphs; (iv) a new proof of the finite model property of the clique-guarded fragment; (v) the small model property of the guarded fragment with optimal bounds; (vi) a polynomial-time solution to the canonisation problem modulo guarded bisimulation, which yields (vii) a capturing result for guarded bisimulation invariant PTIME.Comment: This is an improved and extended version of the paper of the same title presented at LICS 201

Investigations on the cause of soil sickness in fruit trees VII. An actinomycete isolated from rootlets of apple seedlings, the probable cause of specific apple replant disease

Aus früheren Untersuchungen ist abgeleitet worden, dass in Aktinomyzeten, die die Faserwurzeln von Apfelgehölzen besiedeln und schädigen, die wahrscheinliche Ursache der Bodenmüdigkeit zu sehen ist. Versuche, diese Aktinomyzeten zu isolieren, blieben lange erfolglos. Erst nach Erkenntnissen, dass pflanzliche Wuchsstoffe eine entscheidende Rolle bei der Besiedlung der Faserwurzeln durch die Aktinomyzeten spielen und dem Einsatz solcher Wuchsstoffe in den Nährböden, ist es gelungen, eine bislang nicht in Erscheinung getretene Aktinomyzeten-Art zu isolieren. In einem gedämpften und mit diesem Isolat beimpften Boden wiesen Apfelsämlinge deutliche Minderungen des Triebzuwachses auf. Ebenso konnte in den Faserwurzeln die Besiedlung durch Aktinomyzeten festgestellt werden. Diese entsprach in der Häufigkeit und im Erscheinungsbild dem, was aus Untersuchungen an Wurzeln aus müden Böden hinlänglich bekannt war. In diesen Ergebnissen wird eine weitere Untermauerung der Vorstellung gesehen, dass wurzelpathogene Aktinomyzeten die Ursache der Bodenmüdigkeit bei Apfel sind.From earlier investigations it has been deduced, that acti­nomycetes, which colonize and damage the rootlets of apple trees, might be the cause of soil sickness. Attempts to isolate these actinomycetes had been without success for a long time. Foremost, recognizing that plant hormones play a decisive role in the colonization of rootlets by actinomycetes and by introducing such plant hormones into culture media it succeeded to isolate a species of acti­nomycetes, which appeared not earlier. Apple seedlings showed clear diminution of growth in a soil that was steamed and inoculated with this isolate. Additionally, a colonization of rootlets by actinomycetes could be observed, which corresponded in frequency and appea­rance to earlier results from investigations with roots in sick soils. The results are considered a further underpinning of the assumption that root pathogenic actinomycetes are the cause of apple replant disease

The interferon response circuit: Induction and suppression by pathogenic viruses

AbstractType I interferons (IFN-α/β) are potent antiviral cytokines and modulators of the adaptive immune system. They are induced by viral infection or by double-stranded RNA (dsRNA), a by-product of viral replication, and lead to the production of a broad range of antiviral proteins and immunoactive cytokines. Viruses, in turn, have evolved multiple strategies to counter the IFN system which would otherwise stop virus growth early in infection. Here we discuss the current view on the balancing act between virus-induced IFN responses and the viral counterplayers

Does an Analysis of the Pulsatile Secretion Pattern of Adrenocorticotropin and Cortisol Predict the Result of Transsphenoidal Surgery in Cushing’s Disease.

The endocrinological, surgical, and histological findings of patients with ACTH-dependent Cushing's disease were correlated with the pulsatile secretion pattern of ACTH and cortisol and the outcome after transsphenoidal pituitary surgery. A total of 28 patients were studied. The preoperative pulsatile secretion of ACTH and cortisol was assessed by sampling blood at 20-min intervals over 24 h. The pulsatile pattern of secretion was analyzed by the Cluster program. In 21 patients, an ACTH-secreting pituitary adenoma was identified and resected. Of these patients, 18 underwent clinical remission, and their cortisol secretion was suppressed to a normal level by low dose dexamethasone. Histological examinations in the patients with persistent disease revealed normal pituitary in 6 cases, nodular hyperplasia in 1, and ACTH-secreting pituitary adenoma in 3 cases. Analysis of the pulsatile pattern of ACTH and cortisol secretion did not reveal significant differences in timing, frequency, and/or amplitude of ACTH and cortisol pulses in normalized patients and those with persistent disease after surgery. It is concluded that analysis of the secretory pattern is not a suitable method for predicting the outcome of ranssphenoidal surgery in patients with ACTH-dependent Cushing's disease

Endotrophic Mycorrhiza – the cause for the phenomenon of the “Johannis-sprout” of apple trees?

In der Literatur gibt es zahlreiche Angaben über Faktoren, die den Johannistrieb von Apfelgehölzen beeinflussen. Es finden sich aber keine Erklärungen dafür, warum das Triebwachstum der Apfelgehölze 4 bis 5 Wochen nach der Blüte durch Bildung einer terminalen Endknospe eingestellt wird, um nach einer Ruhepause erneut eine zweite, aber vergleichsweise sehr geringe Wachstumsphase einzuleiten. Bei der Besiedlung der Faserwurzeln durch die endotrophe Mykorrhiza sind Schäden an den Faserwurzeln in ihrer aktiven Wachstumsphase zunächst nicht erkennbar. Das trifft auch dann zu, wenn Hyphen, Arbuskel und Vesikel in der gesamten Wurzelrinde vorgefunden werden. Mit der Größenzunahme der Vesikel sind allerdings Veränderungen ihrer sonst ovalen Form festgestellt worden. Es handelt sich dabei meist um Einschnürungen, die sehr wahrscheinlich dadurch entstehen, dass das Wurzelrindengewebe mit der Volumenzunahme der Vesikel aufreißt und die entstehenden Hohlräume von ihnen ausgefüllt werden. Diese Erscheinungen gehen mit einer erkennbaren Verringerung des Vitalitätszustandes der Faserwurzeln einher. Somit besteht die Möglichkeit, dass durch diese rein mechanische Schädigung der Faserwurzeln Störungen in der Wasser-und Nährstoffaufnahme sowie im Wuchsstoffhaushalt des Gehölzes ausgelöst werden, die zur Beendigung der ersten Wachstumsphase führen. Deshalb wird die Frage aufgeworfen, ob darin die Ursache für den Abschluss der ersten Wachstumsphase der Apfelgehölze und damit für den nachfolgenden Johannistrieb zu suchen sein könnte.In the literature there are many explanations for the factors which influence the midsummer sprout, the so called “Johannis-sprout“. However there are no explanations for the fact that the shoot growth of apple trees stops 4 to 5 weeks after blossoming by developing terminal final buds. After a resting time they start a new but very unimportant shoot growth. With respect to root colonizing by arbuscular mycorrhiza, damages in the rootlets are first of all not visible in the period of active root growth. This is also true if hypha, arbuscules and vesicles are occupying the whole root cortex. But with extending of the volume of vesicles there take place variations in their normal oval shape. These are mostly constrictions which occur if the root cortex is bursting by the enlargement of the vesicles and their occupying the holow spaces. These symptoms correspond mostly with a decreasing vitality of the rootlets. Consequently there exists the possibility that these mechanical damages of the rootlets may be the cause for disturbances in water and nutrient uptake and in the balance of plant hormones in the trees. Therefore the question arises, whether these processes may be responsible for terminating the first shoot growth period and accordingly for the succeeding second growth period, called Johannis-sprout

Integrated knowledge utilization and evolution for the conservation of corporate know-how

Insufficient consideration of knowledge evolution is a frequent cause for the failure of knowledge-based systems (KBSs) in industrial practice. Corporate know-how about the design and manufacturing of a particular product is subject to rather rapid changes, and it is hard to specify in advance exactly what information will be requested by various users. Keeping a KBS for the conservation of corporate know-how up-to-date or even enhancing its utility, thus requires the continuous monitoring of its performance, noting deficiencies, and suggestions for improvements. In the current paper, we discuss different ways in which information collected during knowledge utilization can be exploited for system evolution. We present structure-based rule and concept editors which allow for an immediate integration and formalization of new information, even by rather inexperienced users. A prototypical knowledge conservation system for crankshaft design which was developed in cooperation between the DFKI and a German company is used to illustrate and evaluate our approach

The Calcineurin-FoxO-MuRF1 signaling pathway regulates myofibril integrity in cardiomyocytes.

Altered Ca2+ handling is often present in diseased hearts undergoing structural remodeling and functional deterioration. However, whether Ca2+ directly regulates sarcomere structure has remained elusive. Using a zebrafish ncx1 mutant, we explored the impacts of impaired Ca2+ homeostasis on myofibril integrity. We found that the E3 ubiquitin ligase murf1 is upregulated in ncx1-deficient hearts. Intriguingly, knocking down murf1 activity or inhibiting proteasome activity preserved myofibril integrity, revealing a MuRF1-mediated proteasome degradation mechanism that is activated in response to abnormal Ca2+ homeostasis. Furthermore, we detected an accumulation of the murf1 regulator FoxO in the nuclei of ncx1-deficient cardiomyocytes. Overexpression of FoxO in wild type cardiomyocytes induced murf1 expression and caused myofibril disarray, whereas inhibiting Calcineurin activity attenuated FoxO-mediated murf1 expression and protected sarcomeres from degradation in ncx1-deficient hearts. Together, our findings reveal a novel mechanism by which Ca2+ overload disrupts myofibril integrity by activating a Calcineurin-FoxO-MuRF1-proteosome signaling pathway