scholarly journals Whistling in the Dark: an Acoustic Study of Little Spotted Kiwi

2021 ◽  
Author(s):  
◽  
Andrew Digby
Keyword(s):  
Microphone Array ◽  
Individual Identification ◽  
Territorial Defence ◽  
Calling Behaviour ◽  
Low Genetic Diversity ◽  
Vocal Behaviour ◽  
Acoustic Study ◽  
Wide Range ◽  
Non Linear ◽  
Threatened Taxa

<p>Song function and evolution are two central topics of avian bioacoustic research. Discerning why birds sing and why they have such diversity of song can yield rich information on behaviour and speciation, and can provide important tools for conservation. Knowledge of vocal behaviour of a wide range of bird groups is necessary, yet avian bioacoustic studies have been hampered by a bias towards male song birds, with many species and even whole groups relatively unstudied. The New Zealand kiwi (Apterygidae) are vocal and threatened taxa, and calls play an important part in their conservation. Yet kiwi acoustic behaviour is poorly understood, and although the five species differ significantly in their ecology, only one has been subject to detailed acoustic study. This thesis addresses this gap in knowledge of kiwi ecology with the first acoustic study of the little spotted kiwi (LSK). The principal aims are to improve understanding of kiwi calling behaviour, and to provide further acoustic tools for kiwi conservation. On a broader scale, enhanced knowledge of the acoustic ecology of the taxonomically and ecologically distinct kiwi will provide insight into song function and signal evolution in all birds. Sexual call dimorphism in LSK is shown to be unrelated to size differences, and instead has likely functional significance, with male calls more suited for territorial defence. There is striking ‘acoustic cooperation’ between the sexes which constrains the function of duets in LSK. Analysis of complex vocal features, the first in any ratite, reveals that two-voicing is unexpectedly rare in this species, but that non-linear phenomena are common. Their association with territorial calls and high frequencies indicates that these features provide acoustic emphasis to enhance resource defence or convey aggression or fitness information. Non-linear phenomena are very common in nestling LSK calls, in accordance with the hypothesis that they add unpredictability to prevent habituation. LSK have surprisingly low inter-individual call variability, suggesting that this species may not use calls for individual identification. This lack of variability may be a result of the low genetic diversity in this species. A long-term dataset reveals significant fluctuations in calling rates with temporal and environmental factors. These trends indicate that calls serve an important function for reproduction and pair contact, and that calls may reflect foraging activity. They also provide evidence that kiwi are adversely affected by light pollution. A comparison of automated acoustic methods with manual call counts shows that while they have a different biases, autonomous techniques are highly effective for kiwi conservation monitoring. Microphone array methods have great potential for enhancing conservation and behavioural information through spatial monitoring of kiwi, but are demonstrated not to be suitable with currently available equipment.</p>

scholarly journals Whistling in the Dark: an Acoustic Study of Little Spotted Kiwi

2021 ◽  
Author(s):  
◽  
Andrew Digby
Keyword(s):  
Microphone Array ◽  
Individual Identification ◽  
Territorial Defence ◽  
Calling Behaviour ◽  
Low Genetic Diversity ◽  
Vocal Behaviour ◽  
Acoustic Study ◽  
Wide Range ◽  
Non Linear ◽  
Threatened Taxa

<p>Song function and evolution are two central topics of avian bioacoustic research. Discerning why birds sing and why they have such diversity of song can yield rich information on behaviour and speciation, and can provide important tools for conservation. Knowledge of vocal behaviour of a wide range of bird groups is necessary, yet avian bioacoustic studies have been hampered by a bias towards male song birds, with many species and even whole groups relatively unstudied. The New Zealand kiwi (Apterygidae) are vocal and threatened taxa, and calls play an important part in their conservation. Yet kiwi acoustic behaviour is poorly understood, and although the five species differ significantly in their ecology, only one has been subject to detailed acoustic study. This thesis addresses this gap in knowledge of kiwi ecology with the first acoustic study of the little spotted kiwi (LSK). The principal aims are to improve understanding of kiwi calling behaviour, and to provide further acoustic tools for kiwi conservation. On a broader scale, enhanced knowledge of the acoustic ecology of the taxonomically and ecologically distinct kiwi will provide insight into song function and signal evolution in all birds. Sexual call dimorphism in LSK is shown to be unrelated to size differences, and instead has likely functional significance, with male calls more suited for territorial defence. There is striking ‘acoustic cooperation’ between the sexes which constrains the function of duets in LSK. Analysis of complex vocal features, the first in any ratite, reveals that two-voicing is unexpectedly rare in this species, but that non-linear phenomena are common. Their association with territorial calls and high frequencies indicates that these features provide acoustic emphasis to enhance resource defence or convey aggression or fitness information. Non-linear phenomena are very common in nestling LSK calls, in accordance with the hypothesis that they add unpredictability to prevent habituation. LSK have surprisingly low inter-individual call variability, suggesting that this species may not use calls for individual identification. This lack of variability may be a result of the low genetic diversity in this species. A long-term dataset reveals significant fluctuations in calling rates with temporal and environmental factors. These trends indicate that calls serve an important function for reproduction and pair contact, and that calls may reflect foraging activity. They also provide evidence that kiwi are adversely affected by light pollution. A comparison of automated acoustic methods with manual call counts shows that while they have a different biases, autonomous techniques are highly effective for kiwi conservation monitoring. Microphone array methods have great potential for enhancing conservation and behavioural information through spatial monitoring of kiwi, but are demonstrated not to be suitable with currently available equipment.</p>

Vocal behaviour of the squirrel glider (Petaurus norfolcensis)

2009 ◽  
Vol 57 (1) ◽  
pp. 55 ◽  
Author(s):  
David J. Sharpe ◽  
Ross L. Goldingay
Keyword(s):  
Vocal Communication ◽  
New South ◽  
Territorial Defence ◽  
North East ◽  
Calling Behaviour ◽  
Vocal Behaviour ◽  
South Wales ◽  
Squirrel Glider ◽  
Animal Handling ◽  
Frequent Call

We describe the vocal behaviour of the squirrel glider (Petaurus norfolcensis) from 465 h of observation across five sites in north-east New South Wales and south-east Queensland. A monosyllabic or polysyllabic nasal grunt was the most frequent call (56% of 208 calls); it ranged from single calls to sequences of up to 20-min duration (mean 2.1 min ± 0.6, s.e.) and was heard on 34% of nights (n = 83) at two sites. The rate of the nasal grunt showed a positive relationship with population density at one site. The nasal grunt was typically made when conspecifics were near the caller, but responses were infrequent (7% of observations). Call playback produced no discernable change in call response. The nasal grunt appears to regulate individual spacing by facilitating mutual avoidance, a function hypothesised to be an evolutionary precursor to the use of calls in territorial defence. Threatening calls were the next most common vocalisation (17% of calls) and were accompanied by scuffles and/or chases. They were also used when gliders were preyed upon and during animal handling. The calling behaviour of the squirrel glider confirms the importance of vocal communication among petaurid gliders.

scholarly journals The many functions of vocal learning

2021 ◽  
Vol 376 (1836) ◽  
pp. 20200235
Author(s):  
Samantha Carouso-Peck ◽  
Michael H. Goldstein ◽  
W. Tecumseh Fitch
Keyword(s):  
Vocal Learning ◽  
Individual Identification ◽  
Theme Issue ◽  
Ecological Traits ◽  
Territorial Defence ◽  
Alarm Calling ◽  
Pair Bonds ◽  
Wide Range ◽  
Selection For ◽  
The Many

The capacity to learn novel vocalizations has evolved convergently in a wide range of species. Courtship songs of male birds or whales are often treated as prototypical examples, implying a sexually selected context for the evolution of this ability. However, functions of learned vocalizations in different species are far more diverse than courtship, spanning a range of socio-positive contexts from individual identification, social cohesion, or advertising pair bonds, as well as agonistic contexts such as territorial defence, deceptive alarm calling or luring prey. Here, we survey the diverse usages and proposed functions of learned novel signals, to build a framework for considering the evolution of vocal learning capacities that extends beyond sexual selection. For each function that can be identified for learned signals, we provide examples of species using unlearned signals to accomplish the same goals. We use such comparisons to generate hypotheses concerning when vocal learning is adaptive, given a particular suite of socio-ecological traits. Finally, we identify areas of uncertainty where improved understanding would allow us to better test these hypotheses. Considering the broad range of potential functions of vocal learning will yield a richer appreciation of its evolution than a narrow focus on a few prototypical species. This article is part of the theme issue ‘Vocal learning in animals and humans’.

scholarly journals On differential operators and unifying relations for 1-loop Feynman integrands

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Kang Zhou
Keyword(s):  
Sigma Model ◽  
Differential Operators ◽  
Linear Sigma Model ◽  
Tree Level ◽  
Maxwell Theory ◽  
Scalar Theory ◽  
Yang Mills ◽  
Loop Level ◽  
Wide Range ◽  
Non Linear

Abstract We generalize the unifying relations for tree amplitudes to the 1-loop Feynman integrands. By employing the 1-loop CHY formula, we construct differential operators which transmute the 1-loop gravitational Feynman integrand to Feynman integrands for a wide range of theories, including Einstein-Yang-Mills theory, Einstein-Maxwell theory, pure Yang-Mills theory, Yang-Mills-scalar theory, Born-Infeld theory, Dirac-Born-Infeld theory, bi-adjoint scalar theory, non-linear sigma model, as well as special Galileon theory. The unified web at 1-loop level is established. Under the well known unitarity cut, the 1-loop level operators will factorize into two tree level operators. Such factorization is also discussed.

scholarly journals Deformation of rockfill in bodies of rockfill dams

2019 ◽  
pp. 5-5
Author(s):  
Mikhail Sainov
Keyword(s):  
Reinforced Concrete ◽  
Deformation Modulus ◽  
Deformation Model ◽  
Observation Data ◽  
Linear Deformation ◽  
Laboratory Test Results ◽  
Wide Range ◽  
Deformation Properties ◽  
Non Linear ◽  
The Impact

Introduction. The main factor determining the stress-strain state (SSS) of rockfill dam with reinforced concrete faces is deformability of the dam body material, mostly rockfill. However, the deformation properties of rockfill have not been sufficiently studied yet for the time being due to technical complexity of the matter, Materials and methods. To determine the deformation parameters of rockfill, scientific and technical information on the results of rockfill laboratory tests in stabilometers were collected and analyzed, as well as field data on deformations in the existing rockfill dams. After that, the values of rockfill linear deformation modulus obtained in the laboratory and in the field were compared. The laboratory test results were processed and analyzed to determine the parameters of the non-linear rockfill deformation model. Results. Analyses of the field observation data demonstrates that the deformation of the rockfill in the existing dams varies in a wide range: its linear deformation modulus may vary from 30 to 500 МPа. It was found out that the results of the most rockfill tests conducted in the laboratory, as a rule, approximately correspond to the lower limit of the rockfill deformation modulus variation range in the bodies of the existing dams. This can be explained by the discrepancy in density and particle sizes of model and natural soils. Only recently, results of rockfill experimental tests were obtained which were comparable with the results of the field measurements. They demonstrate that depending on the stress state the rockfill linear deformation modulus may reach 700 МPа. The processing of the results of those experiments made it possible to determine the parameters on the non-linear model describing the deformation of rockfill in the dam body. Conclusions. The obtained data allows for enhancement of the validity of rockfill dams SSS analyses, as well as for studying of the impact of the non-linear character of the rockfill deformation on the SSS of reinforced concrete faces of rockfill dams.

Non-Linear Dynamic Magneto Electric Effects in Ferromagnetic-Ferroelectric Layered Composites

2013 ◽  
Author(s):  
Satenik Harutyunyan ◽  
Davresh Hasanyan
Keyword(s):  
Vibration Frequency ◽  
Strain Distribution ◽  
Longitudinal Vibration ◽  
Three Dimensional ◽  
Low Frequency ◽  
Structure Design ◽  
Experimental Results ◽  
Physical Parameters ◽  
Wide Range ◽  
Non Linear

A non-linear theoretical model including bending and longitudinal vibration effects was developed for predicting the magneto electric (ME) effects in a laminate bar composite structure consisting of magnetostrictive and piezoelectric multi-layers. If the magnitude of the applied field increases, the deflection rapidly increases and the difference between experimental results and linear predictions becomes large. However, the nonlinear predictions based on the present model well agree with the experimental results within a wide range of applied electric field. The results of the analysis are believed to be useful for materials selection and actuator structure design of actuator in actuator fabrication. It is shown that the problem for bars of symmetrical structure is not divided into a plane problem and a bending problem. A way of simplifying the solution of the problem is found by an asymptotic method. After solving the problem for a laminated bar, formula that enable one to change from one-dimensional required quantities to three dimensional quantities are obtained. The derived analytical expression for ME coefficients depend on vibration frequency and other geometrical and physical parameters of laminated composites. Parametric studies are presented to evaluate the influences of material properties and geometries on strain distribution and the ME coefficient. Analytical expressions indicate that the vibration frequency strongly influences the strain distribution in the laminates, and that these effects strongly influence the ME coefficients. It is shown that for certain values of vibration frequency (resonance frequency), the ME coefficient becomes infinity; as a particular case, low frequency ME coefficient were derived as well.

Rotorcraft control response using linearised and non-linear flight dynamic models with different inflow models

2017 ◽  
Vol 121 (1238) ◽  
pp. 553-575 ◽  
Author(s):  
T. Sakthivel ◽  
C. Venkatesan
Keyword(s):  
Dynamic Model ◽  
Dynamic Models ◽  
Model Identification ◽  
Flight Test ◽  
Step Size ◽  
Response Characteristics ◽  
Wide Range ◽  
Non Linear ◽  
Steady Level ◽  
Control Response

ABSTRACTThe aim of the present study is to develop a relatively simple flight dynamic model which should have the ability to analyse trim, stability and response characteristics of a rotorcraft under various manoeuvring conditions. This study further addresses the influence of numerical aspects of perturbation step size in linearised model identification and integration timestep on non-linear model response. In addition, the effects of inflow models on the non-linear response are analysed. A new updated Drees inflow model is proposed in this study and the applicability of this model in rotorcraft flight dynamics is studied. It is noted that the updated Drees inflow model predicts the control response characteristics fairly close to control response characteristics obtained using dynamic inflow for a wide range of flight conditions such as hover, forward flight and recovery from steady level turn. A comparison is shown between flight test data, the control response obtained from the simple flight dynamic model, and the response obtained using a more detailed aeroelastic and flight dynamic model.

Convergence

2018 ◽  
Author(s):  
Daithí Mac Síthigh
Keyword(s):  
Human Rights ◽  
Public Service ◽  
Audiovisual Media ◽  
On Demand ◽  
European Court ◽  
Wide Range ◽  
Media Services ◽  
Non Linear ◽  
Telecommunications Law

The purpose of this chapter is to explain, in the context of telecommunications law and regulation, the regulation by EU and UK law of audiovisual and radio media services. Overarching principles are found in the Audiovisual Media Services Directive, which takes an approach described as technologically neutral, but established two top-level categories of regulation, for television (or linear) services and on-demand (or non-linear) services. In the case of television services, a wide range of standalone works and comprehensive Sections or chapters on the regulation of broadcasting are available. As such, the focus here (with a view to the interests of readers) is on licensing of content and multiplex services by Ofcom and the handling of complaints about those services, with a bias towards the standard licences for services on cable, satellite, internet, and digital terrestrial platforms, and the regulation of DTT multiplexes and of on-demand services, as opposed to detailed description of the BBC and the commercial public service broadcasters. Indeed, the European Court of Human Rights has regularly found that the regulation of communications infrastructure can have a real impact on the receiving and imparting of information.

Comparative mitochondrial phylogeography of two legless lizards (Pygopodidae) from Queensland’s fragmented woodlands

2020 ◽  
Vol 66 (3-4) ◽  
pp. 142-150
Author(s):  
Jessica Worthington Wilmer ◽  
Andrew P. Amey ◽  
Carmel McDougall ◽  
Melanie Venz ◽  
Stephen Peck ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Evolutionary History ◽  
The West ◽  
European Settlement ◽  
Low Genetic Diversity ◽  
Eastern Australia ◽  
Wide Range ◽  
History Of ◽  
Open Forests ◽  
Fossorial Species

Sclerophyll woodlands and open forests once covered vast areas of eastern Australia, but have been greatly fragmented and reduced in extent since European settlement. The biogeographic and evolutionary history of the biota of eastern Australia’s woodlands also remains poorly known, especially when compared to rainforests to the east, or the arid biome to the west. Here we present an analysis of patterns of mitochondrial genetic diversity in two species of Pygopodid geckos with distributions centred on the Brigalow Belt Bioregion of eastern Queensland. One moderately large and semi-arboreal species, Paradelma orientalis, shows low genetic diversity and no clear geographic structuring across its wide range. In contrast a small and semi-fossorial species, Delma torquata, consists of two moderately divergent clades, one from the ranges and upland of coastal areas of south-east Queensland, and other centred in upland areas further inland. These data point to varying histories of geneflow and refugial persistance in eastern Australia’s vast but now fragmented open woodlands. The Carnarvon Ranges of central Queensland are also highlighted as a zone of persistence for cool and/or wet-adapted taxa, however the evolutionary history and divergence of most outlying populations in these mountains remains unstudied.

On Categorization of Seismic Load As Primary or Secondary for Piping Systems With Hardening Capacity

2018 ◽  
Author(s):  
Pierre B. Labbé
Keyword(s):  
Natural Frequency ◽  
Response Spectrum ◽  
A Priori ◽  
Effective Stiffness ◽  
Linear Oscillator ◽  
Seismic Load ◽  
Wide Range ◽  
Non Linear ◽  
Piping Systems ◽  
Non Linear Oscillator

The concept of primary/secondary categorization is first reviewed and generalized for its application to a non-linear oscillator subjected to a seismic load. Categorizing the seismic load requires calculating the input level associated with the oscillator ultimate capacity and comparing it to the level associated with the plastic yield. To resolve this problem, it is assumed that the non-linear oscillator behaves like a linear equivalent oscillator, with an effective stiffness (or frequency) and an effective damping. However, as it is not a priori possible to predict the equivalent stiffness and damping, a wide range of possibilities is systematically considered. The input motion is represented by its conventional response spectrum. It turns out that key parameters for categorization are i) the “effective stiffness factor” (varying from 0 for perfect damage behaviour to 1 for elastic-perfectly plastic) and the slope of the response spectrum in the vicinity of the natural frequency of the oscillator. Effective damping and spectrum sensitivity to damping play a second order role. A formula is presented that enables the calculation of the primary part of a seismically induced stress as a function of both the oscillator and input spectrum features. The formula is also presented in the form of a diagram. This paper follows-up on a similar paper presented by the author at the PVP 2017 Conference [1]. The new development introduced here is that the oscillator exhibits hardening capacity, while no hardening was assumed in [1]. It appears that the conclusions are slightly modified but the trend is very similar to the non-hardening case. Regarding piping systems, it appears that even when experiencing large plastic strains under beyond design input motions, their observed effective frequency is very close to their natural frequency, decreasing only by a few percents (experimental data from USA, Japan and India are processed). These observations lead to the conclusion that the seismic load, or the seismically induced inertial seismic strains, should basically be regarded as secondary.

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