274 research outputs found
Doctor of Philosophy
dissertationThis dissertation reviews the global status of all avian scavenging birds, including vultures, and synthesizes in-depth fieldwork on the endangered Egyptian vulture Neophron percnopterus in the Middle East and Horn of Africa. Chapter 1 provides a succinct review of the ecology, status, and importance of vultures globally. Chapter 2 evaluates what ecological factors contribute to extinction risk for all 106 avian scavenger species globally. Combined, these chapters show that vultures, which are the only obligate vertebrate scavengers, have experienced the most rapid decline in conservation status of any group of birds over the past decade and comprise the most threatened avian functional guild in the world. By quickly locating and consuming carrion, vultures outcompete and control problematic facultative scavengers (like feral dogs and rats), insects, and microorganisms. When vulture populations decline, carrion becomes increasingly available to other organisms, in a form of terrestrial eutrophication. Furthermore, vultures' highly specialized digestive systems efficiently eradicate diseases when consuming carrion, whereas facultative scavengers are more susceptible to contracting and transmitting diseases among themselves and to humans. Diet, geography, body mass, clutch size, and taxonomy are all strong predictors of extinction risk, but dietary toxins are by far the most important anthropogenic threat to avian scavengers. Chapters 3 and 4 build on extensive fieldwork in the Middle East and the Horn of Africa and satellite-tracking of the endangered Egyptian vulture to illuminate habitat preferences, migration routes, and critical sites to target conservation actions. In Chapter 3, Egyptian vulture habitat use was investigated within home ranges and core use areas. Overall, vultures strongly selected for anthropogenic features, including highways and powerlines in arid areas. In Chapter 4, the most important migratory bottlenecks and stopover sites for the Egyptian vulture on the Red Sea Flyway were identified. Discouragingly, none of the area within the major migratory bottlenecks was protected and only <13% of the area within the major stopovers was protected. This demonstrates a very concerning gap in the protected area network. Combined, Chapters 3 and 4 provide clear guidelines where investment is urgently needed to help conserve endangered vultures in the Middle East and Horn of Africa
Importance of Ethiopian shade coffee farms for forest bird conservation
pre-printCoffee is the most important tropical commodity and is grown in high-priority areas for biological conservation. There is abundant literature on the conservation value of coffee farms internationally, but there has been little research on this topic in Africa. Ethiopia is a diverse and little-studied country with high levels of avian endemism, pressing conservation challenges, and where Coffea arabica originated. We sampled bird communities in shade coffee farms and moist evergreen Afromontane forest in Ethiopia utilizing standard mist netting procedures at seven sites over three years to evaluate bird species richness, diversity and community structure. Although species diversity did not differ between shade coffee and forest, shade coffee farms had over double the species richness of forest sites and all but one of the nine Palearctic migratory species were captured only in shade coffee. There was a greater relative abundance of forest specialists and understory insectivores in forest, demonstrating that little-disturbed forest is critical for sustaining these at-risk groups of birds. Nonetheless, all species recorded in primary forest control sites were also recorded in shade coffee, indicating that Ethiopian shade coffee is perhaps the most "bird-friendly" coffee in the world. This is an important finding 66 for efforts to conserve forest birds in Africa, and for shade coffee farmers that may benefit from avian pest regulation and biodiversity-friendly coffee certifications
Making textile sensors from scratch
This workshop will explore the use of low-cost
materials and tools to build textile-based interfaces.
We will introduce a range of methods for
handcrafting textile sensors and circuitry.
Participants will learn techniques developed by the
workshop leaders and will also be encouraged to
use our material library to design their own custom
sensors. The goal of the workshop is to familiarize
participants with available electronic textile
materials and introduce them to a variety of sensor
and circuitry construction techniques
Priorities for research and action to prevent a New World vulture crisis
Proactive approaches are typically more cost-effective than reactive ones, and this is clearly the case for biodiversity conservation. Research and conservation actions for Old World vultures typically followed large population declines, particularly in Asia and Africa. These are clear examples of reactive intensive conservation management. We here contend that there are signs of a potential upcoming continental vulture crisis in the New World. New Word vultures share many of the threats that have decimated their Old World counterparts, such as toxicosis from poisoning and lead. At the same time, we show that quantitative data on key demographic and conservation action aspects are largely lacking for many New World vultures, particularly those restricted to the Neotropics. This knowledge gap prevents us from quantifying population declines, and in turn, to design effective management actions to mitigate and prevent further declines. Essentially, if the current knowledge gaps are not filled rapidly, we will miss the opportunity to apply proactive conservation. We here propose a set of actions to prevent a potential vulture crisis in the Americas.Peer reviewe
SSBBR-X: Candidate Engine for Concorde
Advances in each component of a low bypass ratio turbofan were considered to improve the performance for Concorde’s mission. The bypass fan will feature a multi-stage design intended to increase pressure ratio and exit velocity of the bypass air to speeds exceeding cruising speed. The multi-stage fan will allow a variable bypass design to be utilized for optimization in different flight regimes. Preliminary research suggests that using a bypass ratio of around 1.0 will be feasible to implement in the design. The exit nozzle will be a variable converging-diverging nozzle to allow for necessary mass flow at different velocities, which is now an industry standard. Compressors of the past have been high in weight with limited pressure ratios, but by using new technologies currently available and new materials proposed to be available, compressors can be lighter and have higher-pressure ratios per stage. Using a bladed disk (or blisk) alone can lead to a weight savings up to 30% and new materials have been proven to have higher operating temperatures, allowing for higher efficiency and thrust for the entire system. New research has proposed a redesign of the burner-turbine system which would reduce the turbine inlet temperatures as well as increase efficiency and thrust. This new system is the Inter-Turbine Burner (ITB) which adds a second combustion chamber in between the high and low-pressure turbine stages. The effect of an ITB is to burn the fuel from the first burner and use all the remaining oxygen in the system. The ITB system eliminates the need for cooling channels in the turbine blades, which subsequently eliminates the need for a cooling system and bleed valves. This reduces the high complexity and weight of turbines while simultaneously reducing the cost of manufacturing traditional blades. Traditional blades are made of superalloys that are manufactured by casting a one direction crystal structure in the metal. New methods for manufacturing blades have been proposed, consisting of using additive manufacturing and advancements in composite materials. Using composites and additive manufacturing, turbine blades can be made with a high tolerance to temperature, which will decrease the TSFC as well as cost. These systems were tested using parametric cycle analysis implemented in MATLAB, VuCalc, GasTurb13, and AxSTREAM to effectively compare their impact on the entire engine and gauge whether any combination of the new component technologies will be ready for a 2028 entry-into-service date. This analysis is a precursor to a different AIAA design competition with the purpose of designing engines to replace those on the Concorde aircraft. The results of this engine will be compared to Concorde’s original Olympus 593 engines to determine if better performance was achieved
Importance of complementary approaches for efficient vulture conservation : reply to Efrat et al
Non peer reviewe
Global raptor research and conservation priorities : Tropical raptors fall prey to knowledge gaps
Abstract Aim Raptors serve critical ecological functions, are particularly extinction-prone and are often used as environmental indicators and flagship species. Yet, there is no global framework to prioritize research and conservation actions on them. We identify for the first time the factors driving extinction risk and scientific attention on raptors and develop a novel research and conservation priority index (RCPI) to identify global research and conservation priorities. Location Global. Methods We use random forest models based on ecological traits and extrinsic data to identify the drivers of risk and scientific attention in all raptors. We then map global research and conservation priorities. Lastly, we model where priorities fall relative to country-level human social indicators. Results Raptors with small geographic ranges, scavengers, forest-dependent species and those with slow life histories are particularly extinction-prone. Research is extremely biased towards a small fraction of raptor species: 10 species (1.8% of all raptors) account for one-third of all research, while one-fifth of species have no publications. Species with small geographic ranges and those inhabiting less developed countries are greatly understudied. Regions of Latin America, Africa and Southeast Asia are identified as particularly high priority for raptor research and conservation. These priorities are highly concentrated in developing countries, indicating a global mismatch between priorities and capacity for research and conservation. Main conclusions A redistribution of scientific attention and conservation efforts towards developing tropical countries and the least-studied, extinction-prone species is critical to conserve raptors and their ecological functions worldwide. We identify clear taxonomic and geographic research and conservation priorities for all raptors, and our methodology can be applied across other taxa to prioritize scientific investment.Peer reviewe
Radiotelemetry reveals key data for the conservation of Sheppardia gabela (Rand, 1957) in the Angolan Escarpment forest
Biodiversity information in Angola is limited or nonexistent, hindering the design and implementation of conservation strategies. The Escarpment forest is one of the most important areas for bird diversity in the country. However, there is almost no information about the territorial needs and habitat preferences of its threatened endemic birds. This study evaluated these needs and preferences in Gabela akalat Sheppardia gabela, a range-restricted endemic to the Central Escarpment. Eighteen individuals of Gabela akalat were captured and radio-tracked with the objectives of establishing their territory size (through home-range size estimates) and habitat preferences using compositional analysis. Home-range sizes were slightly larger than other Sheppardia species and Gabela akalat evidently avoided clearings and preferred forest habitat, although it was also able to use farmland areas and secondary growth to a lesser extent. Conservation measures should focus on the preservation of remaining old-growth forest through the establishment of a nature reserve in Kumbira. To assure the success of such an initiative, the local population should participate in planning, administration and enforcement. We outline some measures that could help address the economic needs of the local community while maintaining forest cover
Paper mechanisms for sonic interaction
ABSTRACT Introducing continuous sonic interaction in augmented popup books enhances the expressive and performative qualities of movables, making the whole narrative experience more engaging and personal. The SaMPL Spring School on Sounding Popables explored the specific topic of paper-driven sonic narratives. Working groups produced several sketches of sonic interactions with movables. The most significant sketches of sounding popables are presented and analyzed
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