On- and Off-Responses in the Inferior Colliculus of the Greater Horseshoe Bat to Pure Tones

1. The auditory threshold curve of averaged evoked potentials of the colliculus inferior in Rhinolophus /errum equinum to pure tone stimulation from 1 to 100 kHz is presented (Fig. 1). For pure tone frequencies lower than 14 ktIz thresholds steeply rise from 20 to 110 db. The steepness of the acoustical filter for 83.3 kHz signals and the frequency of the echoes heard by Greater Horseshoe Bats is accentuated by averaging methods. Because of averaging, evoked potentials thresholds are lowered by about 20 db compared to those obtained by non-averaging methods. 2. Prominent off-responses in evoked potentials appear for three stimulus frequency ranges: 3-10 kHz with a peak at 5 ktIz, 20-40 kHz with a peak at 20 kHz and 80.0-82.6 kHz with a peak at 81.5 kHz (Fig. 2). 3. It is unlikely that beat note frequencies play any role for echolocation. 4. The relevance of these results to echolocation in Horseshoe Bats is discussed, especially as to Doppler shift information contained in the constant frequency part of echoes

die Herausforderung lokaler Vielfalt jenseits der westlichen Welt

Der SFB 700 befasst sich vorwiegend mit Räumen begrenzter Staatlichkeit in Postkolonien. Schon aus diesem Grund ist eine Auseinandersetzung mit postkolonialer Theorie angeraten, beschäftigt sich diese doch mit den Problemen, die entstehen, wenn westliche Denk- und Wahrnehmungsmuster auf nicht-westliche Räume übertragen werden. Solche eurozentristischen Beschreibungen erheben die westliche Moderne zur normativen Vergleichsfolie für gesellschaftliche Entwicklungen in der nicht-westlichen Welt. Auch der SFB 700 läuft Gefahr, die Vielfalt lokaler Konfigurationen des Regierens zu übersehen, weil das Governance- Konzept eine europäisch geprägte Geschichte hat. Wir wollen uns in diesem Arbeitspapier der postkolonialen Kritik stellen, um den Blick der Governance-Forschung für alternative Entwicklungen zu schärfen. In forschungspraktischer Absicht suchen wir bei den Autor/inn/ en des Postkolonialismus-Diskurses nach Hinweisen auf konkrete Governance- Phänomene, die die Kontingenz der westlichen Governance-Vorstellungen sichtbar machen einfach dadurch, dass sie anders sind. Inwieweit tragen postkoloniale Ansätze in den Geistes- und Sozialwissenschaften dazu bei, die räumliche, institutionelle und soziale Diversität von Governance in postkolonialen Räumen begrenzter Staatlichkeit adäquat und konkret zu erfassen?In this paper we intend to examine how postcolonial approaches can be used productively for governance research. The research of the research center (SFB) 700 focuses mainly on areas of limited statehood in postcolonial settings. Postcolonial theories are relevant to this research because they critique the application of Western categories to non-Western contexts. Eurocentric conceptions of governance tend to see the development of Western modernity as a norm by which social phenomena in the non-Western world are measured. By employing such a conception, SFB 700 risks overlooking the diversity of local governance configurations. In this paper we explore the potential of postcolonial critique, when applied to governance research, to better capture these alternative developments in non-Western contexts. The postcolonial discourse focuses on a variety of social, cultural and political developments in postcolonial settings. As a result, it seems particularly qualified to provide insights into concrete governance phenomena in the postcolonial world and to reveal the contingency of Western ideas about governance. To what extent can postcolonial approaches in the humanities and social sciences help us understand the geographical, institutional, and social diversity of governance in postcolonial areas of limited statehood

Foraging behavior and Doppler shift compensation in echolocating hipposiderid bats, I-Iipposideros bicolor and I-Iipposideros speoris

1. Two hipposiderid bats,H. bicolor andH. speoris, were observed in their natural foraging areas in Madurai (South India). Both species hunt close together near the foliage of trees and bushes but they differ in fine structure of preferred hunting space:H. bicolor hunts within the foliage, especially whenH. speoris is active at the same time, whereasH. speoris never flies in dense vegetation but rather in the more open area (Fig. 1, Table 1). 2. Both species emit CF/FM-sounds containing only one harmonic component in almost all echolocation situations. The CF-parts of CF/FM-sounds are species specific within a band of 127–138 kHz forH. speoris and 147–159 kHz forH. bicolor (Tables 2 and 3). 3. H. speoris additionally uses a complex harmonic sound during obstacle avoidance and during laboratory tests for Doppler shift compensation.H. bicolor consistently emits CF/FM-sounds in these same situations (Fig. 2). 4. Both hipposiderid bats respond to Doppler shifts in the returning echoes by lowering the frequency of the emitted sounds (Fig. 3). However, Doppler compensations are incomplete as the emitted frequencies are decreased by only 55% and 56% (mean values) of the full frequency shifts byH. speoris andH, bicolor, respectively. 5. The differences in Doppler shift compensation, echolocating and hunting behavior suggest thatH. speoris is less specialized on echolocation with CF/FM-sounds thanH. bicolor

The use of acoustical cues for prey detection by the Indian false vampire bat, Megaderma lyra

1. The response of the echolocating bat, Megaderma lyra, was tested to different kinds of prey in an outdoor cage. The bats caught larger flying insects (moths, beetles, grasshoppers, and cockroaches) on the wing and also picked up arthropods (solifugid spiders, beetles and cockroaches) and small vertebrates (mice, fishes, frogs and geckoes) from the ground. After touching the prey with the muzzle, the bats were able to differentiate between species. Scorpions and toads were not taken by M. lyra. 2. In lighted and in dark conditions, M. lyra detected and caught prey only when it moved. Dead frogs briskly pulled over the floor were also detected and caught, whereas stationary dead frogs were disregarded by the bats (Table 1). 3. When dead frogs were pulled over the watered surface of a glass plate to eliminate noises by motion, the motion no longer alarmed the bats. From the results of these experiments it was concluded that M. lyra detects prey on the ground by listening to the noise of the moving target only, and not by echolocation (Table 1 C, Fig. 1). Furthermore, M. lyra were not attracted by frog calls. 4. M. lyra differentiated between palatable frogs and non-palatable toads only after touching the prey with the muzzle. 5. Experiments with freshly killed frogs coated with toad secretions or covered with toad skins indicate that M. lyra differentiates between frogs and toads by chemical means. There was no evidence that these prey were differentiated by means of echolocation

Influence of heterogeneous air entry pressure on large scale unsaturated flow in porous media

The paper presents numerical simulations of water infiltration in unsaturated porous media containing coarse-textured inclusions embedded in fine-textured background material. The calculations are performed using the two-phase model for water and air flow and a simplified model known as the Richards equation. It is shown that the Richards equation cannot correctly describe flow in the presence of heterogeneities. However, its performance can be improved by introducing appropriately defined effective capillary and permeability functions, representing largescale behaviour of the heterogeneous medium

An ensemble neural network model for real-time prediction of urban floods

The real-time forecasting of urban flooding is a challenging task for the following two reasons: (1) urban flooding is often characterized by short lead times, (2) the uncertainty in precipitation forecasting is usually high. Standard physically based numerical models are often too slow for the use in real-time forecasting systems. Data driven models have small computational costs and fast computation times and may be useful to overcome this problem. The present study presents an artificial neural network based model for the prediction of maximum water levels during a flash flood event. The challenge of finding a suitable structure for the neural network was solved with a new growing algorithm. The model is successfully tested for spatially uniformly distributed synthetic rain events in two real but slightly modified urban catchments with different surface slopes. The computation time of the model in the order of seconds and the accuracy of the results are convincing, which suggest that the method may be useful for real-time forecasts.Bundesministerium für Bildung und Forschung/Sonderprogramm GEOTECHNOLOGIEN/03G0846A/E

A spatially stabilized TDG based finite element framework for modeling biofilm growth with a multi-dimensional multi-species continuum biofilm model

We consider a model for biofilm growth in the continuum mechanics framework, where the growth of different components of biomass is governed by a time dependent advection–reaction equation. The recently developed time-discontinuous Galerkin (TDG) method combined with two different stabilization techniques, namely the Streamline Upwind Petrov Galerkin (SUPG) method and the finite increment calculus (FIC) method, are discussed as solution strategies for a multi-dimensional multi-species biofilm growth model. The biofilm interface in the model is described by a convective movement following a potential flow coupled to the reaction inside of the biofilm. Growth limiting substrates diffuse through a boundary layer on top of the biofilm interface. A rolling ball method is applied to obtain a boundary layer of constant height. We compare different measures of the numerical dissipation and dispersion of the simulation results in particular for those with non-trivial patterns. By using these measures, a comparative study of the TDG–SUPG and TDG–FIC schemes as well as sensitivity studies on the time step size, the spatial element size and temporal accuracy are presented. The final publication is available at Springer via http://dx.doi.org/10.1007/s00466-017-1388-1State of Lower Saxon

Ontogenesis of tonotopy in inferior colliculus of a hipposiderid bat reveals postnatal shift in frequency-place code

The postnatal development of midbrain tonotopy was investigated in the inferior colliculus (IC) of the south Indian CF-FM bat Hipposideros speoris. The developmental progress of the three-dimensional frequency representation was determined by systematic stereotaxic recordings of multiunit clusters from the 1st up to the 7th postnatal week. Additional developmental measures included the tuning characteristics of single units (Figs. 3f; 4f; 5f), the analysis of the vocalised pulse repertoire (Figs. 3e, 4e, 5e), and morphometric reconstructions of the brains of all experimental animals (Fig. 1). The maturation of auditory processing could be divided into two distinct, possibly overlapping developmental periods: First, up to the 5th week, the orderly tonotopy in the IC developed, beginning with the low frequency representation and progressively adding the high frequency representation. With regard to the topology of isofrequency sheets within the IC, maturation progresses from dorsolateral to ventromedial (Figs. 3c, 4c). At the end of this phase the entire IC becomes specialised for narrowly tuned and sensitive frequency processing. This includes the establishment of the 'auditory fovea', i.e. the extensive spatial representation of a narrow band of behaviorally relevant frequencies in the ventromedial part of the IC. In the 5th postnatal week the auditory fovea is concerned with frequencies from 100-118 kHz (Fig. 4c, d). During subsequent development, the frequency tuning of the auditory fovea increases by 20-25 kHz and finally attains the adult range of ca. 125-140 kHz. During this process, neither the bandwidth of the auditory fovea (15-20 kHz) nor the absolute sensitivity of its units (ca. 50 dB SPL) were changed. Further maturation occurred at the single unit level : the sharpness of frequency tuning increased from the 5th to the 7th postnatal weeks (Q-10-dB-values up to 30-60), and upper thresholds emerged (Figs. 4f, 5f). Although in the adult the frequency of the auditory fovea matches that of the vocalised pulses, none of the juvenile bats tested from the 5th to the 7th weeks showed such a frequency match between vocalisation and audition (Figs. 4e, 5e). The results show that postnatal maturation of audition in hipposiderid bats cannot be described by a model based on a single developmental parameter