216 research outputs found
Income Distribution Dynamics and Cross-Region Convergence in Europe. Spatial filtering and novel stochastic kernel representations
This paper suggests an empirical framework for analysing income distribution
dynamics and cross-region convergence in the European Union of 27 member states, 1995-
2003. The framework lies in the research tradition that allows the state income space to be
continuous, puts emphasis on both shape and intra-distribution dynamics and uses stochastic
kernels for studying transition dynamics and implied long-run behaviour. In this paper
stochastic kernels are described by conditional density functions, estimated by a product
kernel estimator of conditional density and represented by means of novel visualisation tools.
The technique of spatial filtering is used to account for spatial effects, in order to avoid
misguided inferences and interpretations caused by the presence of spatial autocorrelation in
the income distributions. The results reveal a slow catching-up of the poorest regions and a
process of polarisation, with a small group of very rich regions shifting away from the rest of
the cross-section. This is well evidenced by both, the unfiltered and the filtered ergodic
density view. Differences exist in detail, and these emphasise the importance to properly deal
with the spatial autocorrelation problem. (authors' abstract
Timescale-invariant representation of acoustic communication signals by a bursting neuron
Acoustic communication often involves complex sound motifs in which the relative durations of individual elements, but not their absolute durations, convey meaning. Decoding such signals requires an explicit or implicit calculation of the ratios between time intervals. Using grasshopper communication as a model, we demonstrate how this seemingly difficult computation can be solved in real time by a small set of auditory neurons. One of these cells, an ascending interneuron, generates bursts of action potentials in response to the rhythmic syllable-pause structure of grasshopper calls. Our data show that these bursts are preferentially triggered at syllable onset; the number of spikes within the burst is linearly correlated with the duration of the preceding pause. Integrating the number of spikes over a fixed time window therefore leads to a total spike count that reflects the characteristic syllable-to-pause ratio of the species while being invariant to playing back the call faster or slower. Such a timescale-invariant recognition is essential under natural conditions, because grasshoppers do not thermoregulate; the call of a sender sitting in the shade will be slower than that of a grasshopper in the sun. Our results show that timescale-invariant stimulus recognition can be implemented at the single-cell level without directly calculating the ratio between pulse and interpulse durations
Dialektaler Wandel in Hellmonsödt (OÖ)
Dialektaler Wandel in Hellmonsödt (OÖ): Eine empirische Analyse anhand zweier Generationen
Diese Arbeit versucht herauszufinden, inwieweit sich der Sprachgebrauch der Men-schen in der Gemeinde Hellmonsödt verändert. Dabei wird untersucht, ob die sozio-demografischen Faktoren Ausbildung, Situation und Alter im Zusammenhang mit ei-nem sprachlichen Wandel stehen. Dazu werden zwei Generationen interviewt, um de-ren Sprachverhalten herauszufiltern. Die Gewährspersonen der älteren Generation befinden sich in einem Alter zwischen 59 und 85 Jahren, diejenigen der jüngeren Ge-neration in einem Alter zwischen 26 und 40 Jahren. Zu Beginn erfolgte eine Analyse von Gründen für Sprachveränderungsprozesse und ein Portrait der Gemeinde Hell-monsödt. Außerdem werden die Gewährspersonen vorgestellt sowie der Fragebogen und das verwendete Transkriptionssystem erklärt. Die Besonderheiten und Merkmale des bairischen, des oberösterreichischen und des mühlviertlerischen Dialektraumes werden gesucht und aufgezeigt. Am Ende zeigen die Ergebnisse, dass der Faktor Ausbildung in der vorliegenden Studie keine entscheidende Rolle spielt und somit in keiner signifikanten Verbindung zu bestimmten Sprachformen oder sprachlichen Ver-änderungen steht. Der situative Aspekt ist sehr wohl entscheidend für die Wahl sprach-licher Formen, vor allem bei Gewährspersonen der jüngeren Generation. Kommunika-tion mit Kindern oder Gespräche in der Öffentlichkeit führen bei den 26-40 Jährigen zum Code-Switching. Der soziodemografische Faktor Alter stellt sich als entscheidend dar und enthüllt einen Sprachwandel innerhalb der Generationen in der Gemeinde Hellmonsödt. Die Mehrheit der jüngeren Generation weist ein differenzierteres Sprach-verhalten auf als die Mehrheit der älteren Generation. Ein Drittel aller befragten Sprachformen lässt markante Unterschiede zwischen den beiden Generationen erken-nen, wodurch ein Sprachwandel in der Gemeinde Hellmonsödt aufgezeigt wird
Assessment Framework for the Evaluation of Organic Food Processing
Processors having no experience in organic food processing may be not aware tha organic principles are not only relevant in organic production but also apply for the processing of organic food. In contrast, if processors are thinking about investments in new processing technologies or are planning to process organic food and want to evaluate whether the new processing technology or their existing processing technologies comply with the organic principles, they are quickly struggling today to come to a meaningful result as the present regulatory framework does not provide conclusive guidance on organic food processing
Encoding of amplitude modulations by auditory neurons of the locust: influence of modulation frequency, rise time, and modulation depth
Using modulation transfer functions (MTF), we investigated how sound patterns are processed within the auditory pathway of grasshoppers. Spike rates of auditory receptors and primary-like local neurons did not depend on modulation frequencies while other local and ascending neurons had lowpass, bandpass or bandstop properties. Local neurons exhibited broader dynamic ranges of their rate MTF that extended to higher modulation frequencies than those of most ascending neurons. We found no indication that a filter bank for modulation frequencies may exist in grasshoppers as has been proposed for the auditory system of mammals. The filter properties of half of the neurons changed to an allpass type with a 50% reduction of modulation depths. Contrasting to reports for mammals, the sensitivity to small modulation depths was not enhanced at higher processing stages. In ascending neurons, a focus on the range of low modulation frequencies was visible in the temporal MTFs, which describe the temporal locking of spikes to the signal envelope. To investigate the influence of stimulus rise time, we used rectangularly modulated stimuli instead of sinusoidally modulated ones. Unexpectedly, steep stimulus onsets had only small influence on the shape of MTF curves of 70% of neurons in our sample
The Role of Cyclooxygenase-1 and -2 in Sevoflurane-Induced Postconditioning Against Myocardial Infarction
Cyclooxygenase (COX)-2 mediates ischemic pre- and postconditioning as well as anesthetic-induced preconditioning. However, the role of COX-1 and -2 in anesthetic-induced postconditioning has not been investigated. We evaluated the role of COX-1 and -2 in sevoflurane-induced postconditioning in vivo. Pentobarbital-anaesthetized male C57BL/6 mice were subjected to 45 minutes of coronary artery occlusion and 3 hours of reperfusion. Animals received either no intervention, the vehicle dimethyl sulfoxide (DMSO, 10 µL/g intraperitoneally), acetylsalicylic acid (ASA, 5 µg/g intraperitoneally), the selective COX-1 inhibitor SC-560 (10 µg/g intraperitoneally), or the selective COX-2 inhibitor NS-398 (5 µg/g intraperitoneally). 1.0 MAC (minimum alveolar concentration) sevoflurane was administered for 18 minutes during early reperfusion either alone or in combination with ASA, SC-560, and NS-398. Infarct size was determined with triphenyltetrazolium chloride. Statistical analysis was performed using 1-way and 2-way analyses of variance with post hoc Duncan testing. The infarct size in the control group was 44% ± 9%. DMSO (42% ± 7%), ASA (36% ± 6%), and NS-398 (44% ± 18%) had no effect on infarct size. Sevoflurane (17% ± 4%; P < .05) and SC-560 (26% ± 10%; P < .05) significantly reduced the infarct size compared with control condition. Sevoflurane-induced postconditioning was not abolished by ASA (16% ± 5%) and SC-560 (22% ± 4%). NS-398 abolished sevoflurane-induced postconditioning (33% ± 14%). It was concluded that sevoflurane induces postconditioning in mice. Inhibition of COX-1 elicits a myocardial infarct size reduction and does not abolish sevoflurane-induced postconditioning. Blockade of COX-2 abolishes sevoflurane-induced postconditioning. These results indicate that sevoflurane-induced postconditioning is mediated by COX-2
Temporal Processing of Vibratory Communication Signals at the Level of Ascending Interneurons in Nezara viridula (Hemiptera: Pentatomidae)
During mating, males and females of N. viridula (Heteroptera: Pentatomidae) produce sex- and species-specific calling and courtship substrate-borne vibratory signals, grouped into songs. Recognition and localization of these signals are fundamental for successful mating. The recognition is mainly based on the temporal pattern, i.e. the amplitude modulation, while the frequency spectrum of the signals usually only plays a minor role. We examined the temporal selectivity for vibratory signals in four types of ascending vibratory interneurons in N. viridula. Using intracellular recording and labelling technique, we analyzed the neurons' responses to 30 pulse duration/interval duration (PD/ID) combinations. Two response arrays were created for each neuron type, showing the intensity of the responses either as time-averaged spike counts or as peak instantaneous spike rates. The mean spike rate response arrays showed preference of the neurons for short PDs (below 600 ms) and no selectivity towards interval duration; while the peak spike rate response arrays exhibited either short PD/long ID selectivity or no selectivity at all. The long PD/short ID combinations elicited the weakest responses in all neurons tested. No response arrays showed the receiver preference for either constant period or duty cycle. The vibratory song pattern selectivity matched the PD of N. viridula male vibratory signals, thus pointing to temporal filtering for the conspecific vibratory signals already at level of the ascending interneurons. In some neurons the responses elicited by the vibratory stimuli were followed by distinct, regular oscillations of the membrane potential. The distance between the oscillation peaks matched the temporal structure of the male calling song, indicating a possible resonance based mechanism for signal recognition
Neuronal precision and the limits for acoustic signal recognition in a small neuronal network
Recognition of acoustic signals may be impeded by two factors: extrinsic noise, which degrades sounds before they arrive at the receiver’s ears, and intrinsic neuronal noise, which reveals itself in the trial-to-trial variability of the responses to identical sounds. Here we analyzed how these two noise sources affect the recognition of acoustic signals from potential mates in grasshoppers. By progressively corrupting the envelope of a female song, we determined the critical degradation level at which males failed to recognize a courtship call in behavioral experiments. Using the same stimuli, we recorded intracellularly from auditory neurons at three different processing levels, and quantified the corresponding changes in spike train patterns by a spike train metric, which assigns a distance between spike trains. Unexpectedly, for most neurons, intrinsic variability accounted for the main part of the metric distance between spike trains, even at the strongest degradation levels. At consecutive levels of processing, intrinsic variability increased, while the sensitivity to external noise decreased. We followed two approaches to determine critical degradation levels from spike train dissimilarities, and compared the results with the limits of signal recognition measured in behaving animals
Desflurane-induced and ischaemic postconditioning against myocardial infarction are mediated by Pim-1 kinase
BackgroundAnaesthetic-induced (APOST) and ischaemic postconditioning (IPOST) against myocardial infarction are mediated via phosphatidylinositol-3-kinase/Akt. Pim-1 kinase is acting downstream of Akt and has recently been demonstrated to enhance cardiomyocyte survival. We tested the hypothesis that both APOST and IPOST are mediated by Pim-1 kinase.MethodsPentobarbital-anaesthetized male C57BL/6 mice were subjected to 45-min coronary artery occlusion (CAO) and 3-h reperfusion. Animals received either no intervention, the Pim-1 kinase inhibitor II (10??g/g intraperitoneally) or its vehicle dimethy sulfoxide (10??l/g intraperitoneally). Three minutes prior to the end of CAO, 1.0 minimum alveolar concentration desflurane was administered for 18?min alone or in combination with Pim-1 kinase inhibitor II. IPOST was induced by three cycles of each 10-s ischaemia/reperfusion, and animals received either IPOST alone or in combination with Pim-1 kinase inhibitor II. Infarct size was determined with triphenyltetrazolium chloride and area at risk with Evans blue. Protein expression of Pim-1 kinase, Bad, phospho-BadSer112 and B-cell lymphoma 2 was determined using Western immunoblotting analysis.ResultsInfarct size in control animals (CON) was 46?±?3%. Dimethylsulfoxide (47?±?3%) and Pim-1 kinase inhibitor II (44?±?5%) did not significantly reduce infarct size. Desflurane (16?±?2%*; *P?<?0.05 vs. CON) and IPOST (21?±?2%*) significantly reduced infarct size compared with CON. Inhibition of Pim-1 kinase abolished desflurane-induced postconditioning (46?±?4%) and IPOST (44?±?5%). Western blot analysis revealed that only desflurane enhances phosphorylation of Bad at serine 112 that was abrogated by Pim-1 kinase inhibitor II.ConclusionThese data suggest that Pim-1 kinase mediates both desflurane-induced postconditioning and IPOST in mice
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