Depth Enhancement of an Underwater Towed System using Hydrodynamic Depressor

The underwater towed system described here consists of tow cables, a towed body, an acoustic module and tail rope towed behind a surface ship. The required depth at a particular speed of the towing ship is obtained by paying out specified length of cable from the winch. However the excessive drag forces on the various components of the towed system results in impractically large values of cable length, especially at higher speeds. A hydrodynamic depressor is designed to improve the depth performance. The design is evolved based on numerical analysis and towing tank tests. Estimation of depth attained is carried out based on steady state theory of tow cables. Validation of the numerical analysis results is carried out through field evaluation of depressor performance during sea trial of the towed system

Spatial and temporal variation in foraging of breeding red‐throated divers

Differing environmental conditions can have profound effects on many behaviours in animals, especially where species have large geographic ranges. Seasonal changes or progression through life history stages impose differential constraints, leading to changes in behaviours. Furthermore, species which show flexibility in behaviours, may have a higher capacity to adapt to anthropogenic-induced changes to their environment. The red-throated diver (RTD) is an aquatic bird, that is able to forage in both freshwater and marine environments, though little else is known about its behaviours and its capacity to adapt to different environmental conditions. Here, we use time-depth recorders and saltwater immersion loggers to examine the foraging behaviour of RTDs from three regions across northwest Europe. We found that in the breeding season, birds from two regions (Iceland and Scotland) foraged in the marine environment, while birds from Finland, foraged predominantly in freshwater. Most of the differences in diving characteristics were at least partly explained by differences in foraging habitat. Additionally, while time spent foraging did not change through the breeding season, dives generally became more pelagic and less benthic over the season, suggesting RTDs either switched prey or followed vertical prey movements, rather than increasing foraging effort. There was a preference for foraging in daylight over crepuscular hours, with a stronger effect at two of the three sites. Overall, we provide the first investigation of RTD foraging and diving behaviour from multiple geographic regions and demonstrate variation in foraging strategies in this generalist aquatic predator, most likely due to differences in their local environment.Peer reviewe

Winter locations of red-throated divers from geolocation and feather isotope signatures.

Migratory species have geographically separate distributions during their annual cycle, and these areas can vary between populations and individuals. This can lead to differential stress levels being experienced across a species range. Gathering informa-tion on the areas used during the annual cycle of red- throated divers (RTDs; Gavia stel-lata) has become an increasingly pressing issue, as they are a species of concern when considering the effects of disturbance from offshore wind farms and the associated ship traffic. Here, we use light- based geolocator tags, deployed during the summer breeding season, to determine the non- breeding winter location of RTDs from breed-ing locations in Scotland, Finland, and Iceland. We also use δ15N and δ13C isotope signatures, from feather samples, to link population- level differences in areas used in the molt period to population- level differences in isotope signatures. We found from geolocator data that RTDs from the three different breeding locations did not overlap in their winter distributions. Differences in isotope signatures suggested this spatial separation was also evident in the molting period, when geolocation data were unavailable. We also found that of the three populations, RTDs breeding in Iceland moved the shortest distance from their breeding grounds to their wintering grounds.In contrast, RTDs breeding in Finland moved the furthest, with a westward migration from the Baltic into the southern North Sea. Overall, these results suggest that RTDs breeding in Finland are likely to encounter anthropogenic activity during the win-ter period, where they currently overlap with areas of future planned developments. Icelandic and Scottish birds are less likely to be affected, due to less ship activity and few or no offshore wind farms in their wintering distributions. We also demonstrate that separating the three populations isotopically is possible and suggest further work to allocate breeding individuals to wintering areas based solely on feather samples.Migratory species have geographically separate distributions during their annual cycle, and these areas can vary between populations and individuals. This can lead to differential stress levels being experienced across a species range. Gathering information on the areas used during the annual cycle of red-throated divers (RTDs; Gavia stellata) has become an increasingly pressing issue, as they are a species of concern when considering the effects of disturbance from offshore wind farms and the associated ship traffic. Here, we use light-based geolocator tags, deployed during the summer breeding season, to determine the non-breeding winter location of RTDs from breeding locations in Scotland, Finland, and Iceland. We also use delta N-15 and delta C-13 isotope signatures, from feather samples, to link population-level differences in areas used in the molt period to population-level differences in isotope signatures. We found from geolocator data that RTDs from the three different breeding locations did not overlap in their winter distributions. Differences in isotope signatures suggested this spatial separation was also evident in the molting period, when geolocation data were unavailable. We also found that of the three populations, RTDs breeding in Iceland moved the shortest distance from their breeding grounds to their wintering grounds. In contrast, RTDs breeding in Finland moved the furthest, with a westward migration from the Baltic into the southern North Sea. Overall, these results suggest that RTDs breeding in Finland are likely to encounter anthropogenic activity during the winter period, where they currently overlap with areas of future planned developments. Icelandic and Scottish birds are less likely to be affected, due to less ship activity and few or no offshore wind farms in their wintering distributions. We also demonstrate that separating the three populations isotopically is possible and suggest further work to allocate breeding individuals to wintering areas based solely on feather samples.Peer reviewe

Conflicts of Interest in Sell-side Research and The Moderating Role of Institutional Investors

Because sell-side analysts are dependent on institutional investors for performance ratings and trading commissions, we argue that analysts are less likely to succumb to investment banking or brokerage pressure in stocks highly visible to institutional investors. Examining a comprehensive sample of analyst recommendations over the 1994-2000 period, we find that analysts’ recommendations relative to consensus are positively associated with investment banking relationships and brokerage pressure, but negatively associated with the presence of institutional investor owners. The presence of institutional investors is also associated with more accurate earnings forecasts and more timely re-ratings following severe share price falls

The Artist in the Library

Through the course of this paper I seek to intertwine a story of my own creative relationship with libraries with accounts of artists’ work, including the work of my students. My goal is to articulate the ways in which artists work with, in, and on libraries and in doing this to define features of a library aesthetic. It is impossible, writing in London in 2016, to ignore the dire context for UK public libraries. Reductions in local government funding have resulted in widespread disregard by local authorities to their responsibilities under the 1964 Public Libraries and Museums Act – their statutory duty to provide a ‘comprehensive and efficient library service for all persons to make use thereof’. (Culture, Media and Sport Committee 2012, online) Cuts to library services continue apace [{note}]1. Writers, poets, artists and authors add their pleas to the protests against closures [{note}]2, but go largely unheeded. The idea of defining a library aesthetic might seem futile in the face of this austerity drive, but through my analysis of such an aesthetic, I hope to explore the potential of artworks to highlight and extend our understanding of its possibilities

The Helicobacter pylori Genome Project : insights into H. pylori population structure from analysis of a worldwide collection of complete genomes

Helicobacter pylori, a dominant member of the gastric microbiota, shares co-evolutionary history with humans. This has led to the development of genetically distinct H. pylori subpopulations associated with the geographic origin of the host and with differential gastric disease risk. Here, we provide insights into H. pylori population structure as a part of the Helicobacter pylori Genome Project (HpGP), a multi-disciplinary initiative aimed at elucidating H. pylori pathogenesis and identifying new therapeutic targets. We collected 1011 well-characterized clinical strains from 50 countries and generated high-quality genome sequences. We analysed core genome diversity and population structure of the HpGP dataset and 255 worldwide reference genomes to outline the ancestral contribution to Eurasian, African, and American populations. We found evidence of substantial contribution of population hpNorthAsia and subpopulation hspUral in Northern European H. pylori. The genomes of H. pylori isolated from northern and southern Indigenous Americans differed in that bacteria isolated in northern Indigenous communities were more similar to North Asian H. pylori while the southern had higher relatedness to hpEastAsia. Notably, we also found a highly clonal yet geographically dispersed North American subpopulation, which is negative for the cag pathogenicity island, and present in 7% of sequenced US genomes. We expect the HpGP dataset and the corresponding strains to become a major asset for H. pylori genomics

First biologging record of a foraging Red-Throated Loon Gavia stellata shows shallow and efficient diving in freshwater environments

Recently, Red-throated Loons Gavia stellata (RTL) have been the subject of increased interest due to their negative interactions with shipping, offshore wind farms, and other marine industry activities. This has driven a desire to quantify the behaviour and ecology of this understudied species, particularly during the non-breeding season. To achieve this, Time Depth Recorder (TDR) and Global Location Sensor (GLS) tags were deployed on individuals from several European locations. Due to an incidental mortality, one set of tags was retrieved early. The single set of tags recorded activity from June to August 2018. The TDR collected records for 14 d, providing the first ever biologging data on RTL foraging in Europe. The bird was tagged 90 km from the coast; therefore, it only used freshwater lakes and was never recorded entering saltwater. The individual mostly undertook shallow dives, with maximum and mean depths of 20 m and 5.4 m, respectively. Foraging constituted 22.9% of total activity during the sampling period. The RTL had diel foraging patterns. with dives being shallower and more frequent at times of "twilight" compared to "daylight." These results provide novel information on an RTL's diurnal patterns of water depth usage and foraging effort during the summer, demonstrating the potential of data loggers to provide key insights into the foraging ecology of this speciesPeer reviewe

UM PROTOCOLO PARA A ALOCAÇÃO DE RECURSOS E CONTROLE DE ACESSO EM REDES EM MALHA SEM FIO

This paper presents a protocol for resource allocation and access control in wireless mesh networks. Resource allocation allows select a different channel in order to reduce the interference in the transmission of data between neighboring devices. Moreover, the use of different channels allows multiple devices to transmit data simultaneously, increasing the total throughput in the network. The access control notifies neighbors which channel the communication will occur and control access to the channel. The experiments are performed on scenarios of wireless networks using NS-3 simulator. The results show that the use of two channels has similar values to the use a single channel, but according the number of channels increases, the network throughput also increases