Dietary studies in birds: testing a non-invasive method using digital photography in seabirds

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Dietary studies give vital insights into foraging behaviour, with implications for understanding changing environmental conditions and the anthropogenic impacts on natural resources. Traditional diet sampling methods may be invasive or subject to biases, so developing non-invasive and unbiased methods applicable to a diversity of species is essential. We used digital photography to investigate the diet fed to chicks of a prey-carrying seabird and compared our approach (photo-sampling) to a traditional method (regurgitations) for the greater crested tern Thalasseus bergii. Over three breeding seasons, we identified >24 000 prey items of at least 48 different species, more than doubling the known diversity of prey taken by this population of terns. We present a method to estimate the length of the main prey species (anchovy Engraulis encrasicolus) from photographs, with an accuracy <1 mm and precision ~ 0·5 mm. Compared to regurgitations at two colonies, photo-sampling produced similar estimates of prey composition and size, at a faster species accumulation rate. The prey compositions collected by two researchers photo-sampling concurrently were also similar. Photo-sampling offers a non-invasive tool to accurately and efficiently investigate the diet composition and prey size of prey-carrying birds. It reduces biases associated with observer-based studies and is simple to use. This methodology provides a novel tool to aid conservation and management decision-making in the light of the growing need to assess environmental and anthropogenic change in natural ecosystems.Department of Science and Technology, South Afric

Dietary studies in birds: testing a non-invasive method using digital photography in seabirds

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.© 2016 The Authors. Methods in Ecology and Evolution © 2016 British Ecological Society Dietary studies give vital insights into foraging behaviour, with implications for understanding changing environmental conditions and the anthropogenic impacts on natural resources. Traditional diet sampling methods may be invasive or subject to biases, so developing non-invasive and unbiased methods applicable to a diversity of species is essential. We used digital photography to investigate the diet fed to chicks of a prey-carrying seabird and compared our approach (photo-sampling) to a traditional method (regurgitations) for the greater crested tern Thalasseus bergii. Over three breeding seasons, we identified > 24 000 prey items of at least 48 different species, more than doubling the known diversity of prey taken by this population of terns. We present a method to estimate the length of the main prey species (anchovy Engraulis encrasicolus) from photographs, with an accuracy < 1 mm and precision ~ 0·5 mm. Compared to regurgitations at two colonies, photo-sampling produced similar estimates of prey composition and size, at a faster species accumulation rate. The prey compositions collected by two researchers photo-sampling concurrently were also similar. Photo-sampling offers a non-invasive tool to accurately and efficiently investigate the diet composition and prey size of prey-carrying birds. It reduces biases associated with observer-based studies and is simple to use. This methodology provides a novel tool to aid conservation and management decision-making in the light of the growing need to assess environmental and anthropogenic change in natural ecosystems.Department of Science and Technology-Centre of Excellence Gran

Calvino’s posthuman journey : a posthuman and ecocritical analysis of three works by Italo Calvino

This dissertation offers a posthuman and ecocritical analysis of three works – Marcovaldo, Palomar, and Le cosmicomiche by Italian writer Italo Calvino. It explores the potential of moving beyond anthropocentricism and into a hybrid space in which human and nonhuman life coexist and collaborate. The urban center is a significant place of this convergence. Underlying these novels is Calvino’s prescient concern for global industrialization, consumerism, and climate change. Posthumanism and ecocriticism overlap in their desire to combat these ongoing environmental crises onset by rapid human development in the 20th century. The omnipresence of animals in these stories also highlight Calvino’s resistance to see humans as an exceptional planetary species. By giving voice, thoughts, and agency to these animals, Calvino’s novels shift the hierarchy into a decentered space in which humans are not considered special or unique. Posthumanism reinforces this position.French and Italia

A non-invasive approach to estimate the energetic requirements of an increasing seabird population in a perturbed marine ecosystem

This is the author accepted manuscript. The final version is available from Springer Nature via the DOI in this record.There is a growing desire to integrate the food requirements of predators living in marine ecosystems impacted by humans into sustainable fisheries management. We used non- invasive video-recording, photography and focal observations to build time-energy budget models and to directly estimate the fish mass delivered to chicks by adult greater crested terns Thalasseus bergii breeding in the Benguela ecosystem. Mean modelled adult daily food intake increased from 140.9 g·d−1 of anchovy Engraulis capensis during incubation to 171.7g·d−1 and 189.2 g·d−1 when provisioning small and large chicks, respectively. Modelled prey intake expected to be returned to chicks was 58.3 g·d−1 (95% credible intervals: 44.9–75.8 g·d−1) over the entire growth period. Based on our observations, chicks were fed 19.9 g·d−1 (17.2–23.0 g·d−1) to 45.1 g·d−1 (34.6–58.7 g·d−1 25 ) of anchovy during early and late provisioning, respectively. Greater crested terns have lower energetic requirements at the individual (range: 15–34%) and population level (range: 1–7%) than the other Benguela endemic seabirds that feed on forage fish. These modest requirements – based on a small body size and low flight costs – coupled with foraging plasticity have allowed greater crested terns to cope with changing prey availability, unlike the other seabirds species using the same exploited prey base.Our research was supported by a Department of Science and Technology-National Research Foundation Centre of Excellence grant to the FitzPatrick Institute of African Ornithology, the Leiden Conservation Foundation (RBS) and our institutes. Robben Island Museum provided logistical support and access to the tern colonies

How many can you catch? Factors influencing the occurrence of multi-prey loading in provisioning Greater Crested Terns

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Seabirds use several methods to transport food to their chicks; most species carry food in their stomachs or crops, but some terns and auks carry prey in their bills. Terns usually only carry one prey item at a time, limiting the rate at which they can provision their chicks, and restricting their effective foraging range. However, some terns do occasionally carry multiple prey, which should offer a selective advantage, but there are very few studies investigating the factors influencing the occurrence of multi-prey loading. We investigated the occurrence of multi-prey loads in provisioning Greater Crested Terns (Swift Tern) Thalasseus bergii bergii breeding on Robben Island, South Africa. Of 24 173 loads photographed, 1.3% comprised multiple prey items. Up to 11 fish were carried at once, but most multi-prey loads contained two Anchovies Engraulis encrasicolus, the most common prey item for this population of terns. Mixed species prey were recorded for the first time in a tern. Multi-prey loads occurred more frequently during mid- and late-provisioning, presumably because large chicks can cope with multiple prey, and have higher energetic requirements than small chicks. Mean standard length of Anchovies in multi-prey prey loads was less than Anchovies in single loads, possibly suggesting terns compensate for smaller prey sizes by bringing multiple prey back to their chick. The orientation of multiple Anchovies in a tern’s bill tended to be the same, suggesting that they were captured from polarised fish schools. At least some multi-prey loads were caught in a single dive.Our research was supported by a Department of Science and Technology–National Research Foundation grant to the Centre of Excellence at the FitzPatrick Institute of African Ornithology, the Leiden Conservation Foundation (RBS) and our institutes. SANParks and Robben Island Museum provided logistical support and access to the tern colonies. This research was approved by SANParks (CONM1182), the Department of Environmental Affairs (RES2013/24, RES2014/83 and RES2015/65) and the animal ethics committee of the University of Cape Town (2013/V3/TC)

Simulation and Test of UAV Tasks with Resource-Constrained Hardware in the Loop

Simulations are indispensable to reduce costs and risks when developing and testing algorithms for unmanned aerial vehicles (UAV) especially for applications in high risk scenarios like search and rescue (SAR) operations and post-disaster damage assessment. Many UAV applications require real-time tasks for which the timeliness of computations is fundamental. However, standard simulation tools are not guaranteed to run in sync with real-time events, leading to unreliable assessments of the ability of the target hardware to perform specific tasks. In this work we present a simulation and test system able to run UAV tasks on resource-constrained target hardware possibly adopted in these applications. The system allows for hardware-in-the-loop simulations in which a virtual UAV provided with virtual sensors is controlled by the software under test (SUT) running on the target hardware, while simulated and real time are kept in sync. We provide experimental results from the execution of several increasingly difficult tasks in the system

The costs of kleptoparasitism: a study of mixed-species seabird breeding colonies

This is the author accepted manuscript. The final version is available from OUP via the DOI in this record.Mixed-species assemblages are common in nature, providing mutual benefits to associating species including anti-predator advantages or resource facilitation. However, associating with other species may also impose costs through kleptoparasitism (food theft). Identification of these costs, and how they vary when different species breed alongside one another, is essential to understand the payoffs of mixed-species assemblages. We explore the costs of kleptoparasitism for greater crested terns Thalasseus bergii provisioning offspring at a single-species colony, where individuals suffer kleptoparasitism from conspecifics, and at a mixed colony where terns breed alongside Hartlaub’s gulls Chroicocephalus hartlaubii and are vulnerable to both intra and interspecific kleptoparasitism. Gull presence likely contributes to increases in both kleptoparasitic attacks and the proportion of prey lost or stolen during provisioning, relative to the single-species colony. Provisioning adults suffered additional energetic costs in response to gull kleptoparasitism, requiring more attempts to deliver prey, taking longer to do so, and swallowing more prey (to the detriment of their offspring). Gulls also appear to increase the duration of tern vulnerability to kleptoparasitism, because they continued to steal food from adults and chicks after precocial chicks left the nest, when intraspecific kleptoparasitism is negligible. Terns breeding in a mixed colony, therefore, suffer direct and indirect costs through decreased provisioning and increased provisioning effort, which may ultimately affect reproductive success, resulting in colony decline where kleptoparasitism is frequent. This study illustrates how forming a mixed-species seabird breeding assemblage has costs as well as benefits, potentially fluctuating between a parasitic and a mutualistic relationship.This work was supported by a Department of Science and TechnologyCentre of Excellence grant to the FitzPatrick Institute of African Ornithology. R.B.S.  was supported by a fellowship from the Leiden Conservation Foundation. This research was approved by SANParks (CONM1182), the Department of Environmental Affairs (RES2013/24, RES2014/83, and RES2015/65) and the animal ethics committee of the University of Cape Town (2013/V3/TC)

Co-evolution, opportunity seeking and institutional change: Entrepreneurship and the Indian telecommunications industry 1923-2009

"This is an Author's Original Manuscript of an article submitted for consideration in Business History [copyright Taylor & Francis]; Business History is available online at http://www.tandfonline.com/." 10.1080/00076791.2012.687538In this paper, we demonstrate the importance for entrepreneurship of historical contexts and processes, and the co-evolution of institutions, practices, discourses and cultural norms. Drawing on discourse and institutional theories, we develop a model of the entrepreneurial field, and apply this in analysing the rise to global prominence of the Indian telecommunications industry. We draw on entrepreneurial life histories to show how various discourses and discursive processes ultimately worked to generate change and the creation of new business opportunities. We propose that entrepreneurship involves more than individual acts of business creation, but also implies collective endeavours to shape the future direction of the entrepreneurial field

A 3D Human Posture Approach for Activity Recognition Based on Depth Camera

Human activity recognition plays an important role in the context of Ambient Assisted Living (AAL), providing useful tools to improve people quality of life. This work presents an activity recognition algorithm based on the extraction of skeleton joints from a depth camera. The system describes an activity using a set of few and basic postures extracted by means of the X-means clustering algorithm. A multi-class Support Vector Machine, trained with the Sequential Minimal Optimization is employed to perform the classification. The system is evaluated on two public datasets for activity recognition which have different skeleton models, the CAD-60 with 15 joints and the TST with 25 joints. The proposed approach achieves precision/recall performances of 99.8 % on CAD-60 and 97.2 %/91.7 % on TST. The results are promising for an applied use in the context of AAL

The BioDICE Taverna plugin for clustering and visualization of biological data: a workflow for molecular compounds exploration

Background: In many experimental pipelines, clustering of multidimensional biological datasets is used to detect hidden structures in unlabelled input data. Taverna is a popular workflow management system that is used to design and execute scientific workflows and aid in silico experimentation. The availability of fast unsupervised methods for clustering and visualization in the Taverna platform is important to support a data-driven scientific discovery in complex and explorative bioinformatics applications. Results: This work presents a Taverna plugin, the Biological Data Interactive Clustering Explorer (BioDICE), that performs clustering of high-dimensional biological data and provides a nonlinear, topology preserving projection for the visualization of the input data and their similarities. The core algorithm in the BioDICE plugin is Fast Learning Self Organizing Map (FLSOM), which is an improved variant of the Self Organizing Map (SOM) algorithm. The plugin generates an interactive 2D map that allows the visual exploration of multidimensional data and the identification of groups of similar objects. The effectiveness of the plugin is demonstrated on a case study related to chemical compounds. Conclusions: The number and variety of available tools and its extensibility have made Taverna a popular choice for the development of scientific data workflows. This work presents a novel plugin, BioDICE, which adds a data-driven knowledge discovery component to Taverna. BioDICE provides an effective and powerful clustering tool, which can be adopted for the explorative analysis of biological datasets