2,526 research outputs found
Policy options for improving regional fertilizer markets in West Africa:
A primary motivation for this study is to identify a key set of policy options for improving fertilizer markets in West Africa (among Economic Community of West African States member countries) in ways that ultimately will help improve the efficiency of regional markets and lower the transaction costs and fiscal burdens of increasing fertilizer use in the region. Guided by the 2008 fertilizer crisis, many governments are tempted to impose fertilizer subsidies to reduce fertilizer prices. Yet, in an environment riddled with inefficiencies that contribute to the high costs of using fertilizers, the introduction of subsidies only adds more fiscal burden.To carry out the study, we undertook four country case studies to review the key constraints and bottlenecks along the fertilizer supply chain. The countries were Ghana, Mali, Nigeria, and Senegal, and the research included field visits in 2009 and 2010. The current paper is based on the country case study results, complemented by a literature review and analysis of secondary data sources.common fertilizer market, fertilizer use and supply, harmonization of products and regulations, improved technology, policy environment, regional market integration, structure and performance of markets, supply chain,
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Draft Genome Sequence of Bacillus safensis RP10, Isolated from Soil in the Atacama Desert, Chile.
Genome analysis of Bacillus safensis RP10, a strain from the soil of Atacama Desert in northern Chile, reflects a bacterium adapted to live in soil containing high levels of heavy metals, high salt conditions, and low carbon and energy sources
Three-Dimensional Analysis of Deep Space Network Antenna Coverage
There is a need to understand NASA s Deep Space Network (DSN) coverage gaps and any limitations to provide redundant communication coverage for future deep space missions, especially for manned missions to Moon and Mars. The DSN antennas are required to provide continuous communication coverage for deep space flights, interplanetary missions, and deep space scientific observations. The DSN consists of ground antennas located at three sites: Goldstone in USA, Canberra in Australia, and Madrid in Spain. These locations are not separated by the exactly 120 degrees and some DSN antennas are located in the bowl-shaped mountainous terrain to shield against radiofrequency interference resulting in a coverage gap in the southern hemisphere for the current DSN architecture. To analyze the extent of this gap and other coverage limitations, simulations of the DSN architecture were performed. In addition to the physical properties of the DSN assets, the simulation incorporated communication forward link calculations and azimuth/elevation masks that constrain the effects of terrain for each DSN antenna. Analysis of the simulation data was performed to create coverage profiles with the receiver settings at a deep space altitudes ranging from 2 million to 10 million km and a spherical grid resolution of 0.25 degrees with respect to longitude and latitude. With the results of these simulations, two- and three-dimensional representations of the area without communication coverage and area with coverage were developed, showing the size and shape of the communication coverage gap projected in space. Also, the significance of this communication coverage gap is analyzed from the simulation data
Novel Bio-Logging Tool for Studying Fine-Scale Behaviors of Marine Turtles in Response to Sound
Increases in the spatial scale and intensity of activities that produce marine anthropogenic sound highlight the importance of understanding the impacts and effects of sound on threatened species such as marine turtles. Marine turtles detect and behaviorally respond to low-frequency sounds, however few studies have directly examined their behavioral responses to specific types or intensities of anthropogenic or natural sounds. Recent advances in the development of bio-logging tools, which combine acoustic and fine-scale movement measurements, have allowed for evaluations of animal responses to sound. Here, we describe these tools and present a case study demonstrating the potential application of a newly developed technology (ROTAG, Loggerhead Instruments, Inc.) to examine behavioral responses of freely swimming marine turtles to sound. The ROTAG incorporates a three-axis accelerometer, gyroscope, and magnetometer to record the turtle\u27s pitch, roll, and heading; a pressure sensor to record turtle depth; a hydrophone to record the turtle\u27s received underwater acoustic sound field; a temperature gauge; and two VHF radio telemetry transmitters and antennas for tag and turtle tracking. Tags can be programmed to automatically release via a timed corrodible link several hours or days after deployment. We describe an example of the data collected with these tags and present a case study of a successful ROTAG deployment on a juvenile green turtle (Chelonia mydas) in the ParanaguĂĄ Estuary Complex, Brazil. The tag was deployed for 221 min, during which several vessels passed closely (\u3c2 km) by the turtle. The concurrent movement and acoustic data collected by the ROTAG were examined during these times to determine if the turtle responded to these anthropogenic sound sources. While fine-scale behavioral responses were not apparent (second-by-second), the turtle did appear to perform dives during which it remained still on or near the sea floor during several of the vessel passes. This case study provides proof of concept that ROTAGs can successfully be applied to free-ranging marine turtles to examine their behavioral response to sound. Finally, we discuss the broad applications that these tools have to study the fine-scale behaviors of marine turtles and highlight their use to aid in marine turtle conservation and management
The Short Rotation Period of Hi'iaka, Haumea's Largest Satellite
Hi'iaka is the larger outer satellite of the dwarf planet Haumea. Using
relative photometry from the Hubble Space Telescope and Magellan and a phase
dispersion minimization analysis, we have identified the rotation period of
Hi'iaka to be ~9.8 hrs (double-peaked). This is ~120 times faster than its
orbital period, creating new questions about the formation of this system and
possible tidal evolution. The rapid rotation suggests that Hi'iaka could have a
significant obliquity and spin precession that could be visible in light curves
within a few years. We then turn to an investigation of what we learn about the
(presently unclear) formation of the Haumea system and family based on this
unexpectedly rapid rotation rate. We explore the importance of the initial
semi-major axis and rotation period in tidal evolution theory and find they
strongly influence the time required to despin to synchronous rotation,
relevant to understanding a wide variety of satellite and binary systems. We
find that despinning tides do not necessarily lead to synchronous spin periods
for Hi'iaka, even if it formed near the Roche limit. Therefore the short
rotation period of Hi'iaka does not rule out significant tidal evolution.
Hi'iaka's spin period is also consistent with formation near its current
location and spin up due to Haumea-centric impactors.Comment: 21 pages with 6 figures, to be published in The Astronomical Journa
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Keys to academic success for under-represented minority young investigators: recommendations from the Research in Academic Pediatrics Initiative on Diversity (RAPID) National Advisory Committee.
BackgroundAlthough Latinos, African-Americans, and American Indians/Alaska Natives comprise 34% of Americans, these under-represented minorities (URMs) account for only 7% of US medical-school faculty. Even when URMs become faculty, they face many substantial challenges to success. Little has been published, however, on keys to academic success for URM young faculty investigators.MethodsThe Research in Academic Pediatrics Initiative on Diversity (RAPID) goal is to enhance the professional advancement of URM junior faculty pursuing research careers in general academic pediatrics. One important RAPID component is the annual mentoring/career-development conference, which targets URM residents, fellows, and junior faculty, and has included 62 URM participants since its 2013 inception. A conference highlight is the panel discussion on keys to academic success for URM young investigators, conducted by the RAPID National Advisory Committee, a diverse group of leading senior researchers. The article aim was to provide a guide to academic success for URM young investigators using the 2018 RAPID Conference panel discussion. A modified Delphi technique was used to provide a systematic approach to obtaining answers to six key questions using an expert panel: the single most important key to success for URM young investigators; ensuring optimal mentorship; how to respond when patients/families say, "I don't want you to see my child because you are ____"; best strategies for maximizing funding success; how to balance serving on time-consuming committees with enough time to advance research/career objectives; and the single thing you wish someone had told you which would have substantially enhanced your success early on.Results/conclusionsThis is the first published practical guide on keys to academic success for URM young investigators. Identified keys to success included having multiple mentors, writing prolifically, being tenaciously persistent, having mentors who are invested in you, dealing with families who do not want you to care for their child because of your race/ethnicity by seeking to understand the reasons and debriefing with colleagues, seeking non-traditional funding streams, balancing committee work with having enough time to advance one's research and career by using these opportunities to generate scholarly products, and asking for all needed resources when negotiating for new jobs
High-pT Signatures in Vector-Leptoquark Models
We present a detailed analysis of the collider signatures of TeV-scale
massive vector bosons motivated by the hints of lepton flavour non-universality
observed in -meson decays. We analyse three representations that necessarily
appear together in a large class of ultraviolet-complete models: a
colour-singlet (), a colour-triplet (the leptoquark), and a colour
octet (). Under general assumptions for the interactions of these exotic
states with Standard Model fields, including in particular possible
right-handed and flavour off-diagonal couplings for the , we derive a
series of stringent bounds on masses and couplings that constrain a wide range
of explicit new-physics models.Comment: 23 pages, 11 figures. v2: Minor modifications and references added.
v3: Matching the journal version. The Feynrules and UFO files used for this
work can be found at https://feynrules.irmp.ucl.ac.be/wiki/LeptoQuar
Fatal Clostridium sordellii-mediated hemorrhagic and necrotizing gastroenteropathy in a dog: case report
Background: Canine hemorrhagic gastroenteritis (also canine gastrointestinal hemorrhagic syndrome) is commonly associated with Clostridium perfringens, although in some cases the etiology remains unclear. This report describes a fatal acute hemorrhagic and necrotizing gastroenteropathy in a dog associated with Clostridium sordellii, a bacterial species never before identified as the etiological agent of hemorrhagic and necrotizing gastroenteropathy in dogs. Case presentation: A fully vaccinated, eight-year-old, female neutered Labrador presented with a history of vomiting without diarrhea. Clinical examination revealed pink mucous membranes, adequate hydration, normothermia, and normocardia. The dog was discovered deceased the following day. Post-mortem examination showed moderate amounts of dark red, non-clotted fluid within the stomach that extended into the jejunum. Discoloration was noted in the gastric mucosa, liver, lungs, and kidneys, with small petechial hemorrhages present in the endocardium over the right heart base and thymic remnants. Histological analysis demonstrated that the gastric fundic mucosa, the pyloric region, small intestine, and large intestine exhibited superficial coagulative necrosis and were lined with a layer of short Gram-positive rods. Anaerobic culture of the gastric content revealed C. sordellii as the dominant bacterial species and neither Salmonella spp., Campylobacter spp., C. perfringens, nor C. difficile were isolated. Unexpectedly, whole genome sequencing of the C. sordellii isolate showed that it lacked the main plasmid-encoded virulence factors typical of the species, indicating that the genetic determinants of pathogenicity of this strain must be chromosomally encoded. Further phylogenetic analysis revealed it to be genetically similar to C. sordellii isolates associated with gastroenteric disease in livestock, indicating that the infection may have been acquired from the environment. Conclusions: This case demonstrates that C. sordellii can associate with a canine hemorrhagic and necrotizing gastroenteropathy in the absence of C. perfringens and illustrates the benefits of using bacterial whole genome sequencing to support pathological investigations in veterinary diagnostics. These data also update the molecular phylogeny of C. sordellii, indicating a possible pathogenic clade in the environment that is distinct from currently identified clades
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